Device for three-dimensional orthopaedic alignment of surgical implements

Abstract

Provided herein is a system (1000) for assisting a surgical intervention on a bone of a subject comprising: - a jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises: - a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A'), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A'); - a JH passageway (116, 146) disposed in the JH bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention; - a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein: - each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b); - the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (114DASM, 144DASM), co-operate to form the assembled state (114ASM, 144ASM) for a form-fit coupling by the JH passageway (116, 146) to the target region of the bone of the subject for the surgical intervention; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144).

Description

[0001] Device for three-dimensional orthopaedic alignment of surgical implements

[0002] Field

[0003] The invention is broadly in the field of orthopaedic interventions, and in particular relates to a holder for a jig for support one or more surgical implements.

[0004] Background

[0005] Malignant bone tumors represent a significant clinical concern, with osteosarcoma (OS) ranking as the third most prevalent cancer in adolescents. Current therapy comprises chemotherapy and Limb-Salvage Surgery (LSS) utilizing reconstruction prostheses or reconstruction bone. As patient survival rates increase, optimal prosthetic alignment becomes of major importance for ensuring joint functionality and implant longevity. Anatomical variation, tumor-induced loss of important surgical landmarks and the current free-hand surgical methods pose significant challenges in achieving optimal prosthetic or bone alignment.

[0006] Technical problems include:

[0007] - Performing precise osteotomy (surgical bone-cut) perpendicular to the bone while considering tumor margins;

[0008] - Precise endomedullar reaming of the femur;

[0009] - Precise rotational (axial) alignment of the reconstruction prosthesis or host-graft bone construct;

[0010] - Precise coronal (left-right) and sagittal (anterior-posterior) alignment of the reconstruction prosthesis or of the host-graft bone construct;

[0011] - Safeguarding important soft tissue (vessels / nerves / tendons / muscles);

[0012] - Avoidance of drill holes close to the surgical bone-cut.

[0013] The currently described devices aim to overcome the problems in the prior art.

[0014] Summary

[0015] Provided herein is a system (1000) for assisting a surgical intervention on a bone of a subject comprising: - a jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:

[0016] - a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);

[0017] - a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;

[0018] - a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein:

[0019] - each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);

[0020] - the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (1 14DASM, 144DASM), co-operate to form the assembled state (1 14ASM, 144ASM) for a form-fit coupling by the JH passageway (116, 146) to the target region of the bone of the subject for the surgical intervention; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144).

[0021] Also provided herein is a system (1000) for assisting a surgical intervention on a bone of a subject comprising:

[0022] - a jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:

[0023] - a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’); - a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;

[0024] - a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) configured for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein:

[0025] - each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);

[0026] - the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (1 14DASM, 144DASM), are configured to co-operate to form the assembled state (1 14ASM, 144ASM) and the JH passageway (116, 146) for a form-fit coupling to the target region of the bone of the subject for the surgical intervention;

[0027] - the JH bracelet body (114, 144) in the assembled state (1 14ASM, 144ASM) is a circumferentially closed annular ring; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144).

[0028] Preferably, each JH bracelet body segment (114a, 114b; 144a, 144b) contains a segment gap (114a’) configured to allow access to the JH passageway (116, 146) in a peripheral to central direction, wherein the segment gap (114a’) has a geometry of missing JH bracelet body segment(s) (114a, 114b; 144a, 144b) that constitute the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM), and for each and every JH bracelet body segment (114a, 114b; 144a, 144b), the segment gap (114a’) has a minimum outer circumference (Gcircum) that is at least 50% of the total outer circumference (Tcircum) of the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM).

[0029] The system (1000) may further comprise: - a jig (200) configured for dismountable attachment to the jig holder (100), wherein the jig (200) comprises at least one jig bracelet (212, 242), wherein each jig bracelet (212, 242) comprises:

[0030] - a jig bracelet body (214, 244) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);

[0031] - a jig passageway (216, 246) disposed in the jig bracelet body (214, 244) between the proximal end and the distal end;

[0032] - a jig coupling region (218, 248) comprising at least a part of an interior annular circumferential surface of the jig passageway (216, 246) (configured) for dismountable coupling to and alignment with the JH coupling region (218, 248) of the JH bracelet body (114, 144); wherein each jig bracelet body (214, 244) has an assembled state (214ASM, 244ASM) and a disassembled state (214DASM ,244DASM), wherein:

[0033] - each jig bracelet body (214, 244) comprising a plurality (two or more) of CJ bracelet body segments (214a, 214b; 244a, 244b);

[0034] - the plurality of jig bracelet body segments (214a, 214b; 244a, 244b) of each jig bracelet body (214, 244) in the disassembled state (214DASM ,244DASM), (is configured to) co-operate to form the assembled state (214ASM, 244ASM) for

[0035] - coupling to the JH coupling region (118, 148) of the JH bracelet body (114, 144); and

[0036] - retention of the JH bracelet body segments (114a, 114b; 144a, 144b) by the jig bracelet (212, 242) such that JH bracelet body segments (114a, 114b; 144a, 144b) maintain the assembled state (114ASM, 144ASM); wherein each jig bracelet body segment (214a, 214b; 244a, 244b) is a longitudinal segment of the jig bracelet body (214, 244).

[0037] The jig bracelet (212, 242) may be disposed with a placement element (300) that is an element useful during the surgical intervention whose pose with respect to the bone of the subject needs to be known or is readable, wherein the placement element (300) is disposed in known or readable relation with the jig bracelet (212, 242). The jig bracelet (212, 242) may be disposed with a coupling element for a placement element, a jig PE coupling element (226), wherein the placement element (300) is an element useful during the surgical intervention whose pose with respect to the bone of the subject needs to be known or is readable, wherein the placement element (300) is disposed in known or readable relation with the jig bracelet (212, 242).

[0038] The placement element (300) may be:

[0039] - a guide such as a blade guide (310, 310’), a drill guide (330), a slotted guide (340), or an implant guide;

[0040] - a support, such as a rod (350, 350’) or scaffold (352); or

[0041] - a navigation landmark, such as a body having a camera-readable three- dimensional geometry or a transponder that emits an electromagnetic signal that is detectable by a transponder reader.

[0042] The jig holder (100) may comprise a pair of the JH bracelets (112, 142) wherein each JH passageway (116 or 146) of the pair of JH passageways (116, 146) is configured for attachment to a different target region of the same bone of the subject for the intervention.

[0043] The jig (200) may comprises a pair of the jig bracelets (212, 242), wherein each jig bracelet (212, 242) of the pair of jig bracelet (212, 242) is configured for attachment to a different JH bracelet (112, 142) of the pair of the JH bracelets (112, 142).

[0044] Each jig bracelet body segment (214a, 214b; 244a, 244b) preferably comprises one or more fixture elements for attaching the respective jig bracelet body segment (214a, 214b or 244a, 244b) to each other using one or more fasteners, thereby retaining jig bracelet body segments (214a, 214b; 244a, 244b) in the assembled state (214ASM, 244ASM) and retaining the JH bracelet body segments (114a, 114b; 144a, 144b) in the assembled state (1 14ASM, 144ASM).

[0045] The system (1000) may be configured such that the attaching of the respective jig bracelet body segment (214a, 214b or 244a, 244b) is adjustable, such that an adjustment changes a force of clamping applied by the respective jig bracelet body segments (214a, 214b; 244a, 244b) to JH coupling region (118, 148) of the JH bracelet (112, 142).

[0046] The system (1000) may be configured such that the force of clamping applied by the respective jig bracelet body segments (214a, 214b; 244a, 244b) to JH coupling region (118, 148) of the JH bracelet (112, 142) is transmitted to the target region of the bone of the subject.

[0047] Further provided is a computer-implemented method for designing a jig holder (100) as defined herein comprising:

[0048] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;

[0049] - identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0050] - for each target region:

[0051] - determining from the three-dimensional medical image:

[0052] - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;

[0053] - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the J H bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial (pose) relation to the target region;

[0054] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146); wherein the design of the jig holder (100) comprises the three-dimensional structure of the JH bracelet (112, 142) determined for each target region.

[0055] Further provided is a computer-implemented method for designing a jig holder (100) comprised in a system (1000) for assisting a surgical intervention on a bone of a subject comprising wherein:- the jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:

[0056] - a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’); - a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;

[0057] - a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein:

[0058] - each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);

[0059] - the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (1 14DASM, 144DASM), co-operate to form the assembled state (1 14ASM, 144ASM) for a form-fit coupling by the JH passageway (116, 146) to the target region of the bone of the subject for the surgical intervention;

[0060] - the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) forms a circumferentially closed annular ring; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144);the method comprises:

[0061] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;

[0062] - identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0063] - for each target region:

[0064] - determining from the three-dimensional medical image:

[0065] - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region, thereby allowing a form-fitting attachment to the target region of the bone of the subject; - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial (pose) relation to the target region;

[0066] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146); wherein the design of the jig holder (100) comprises the three-dimensional structure of the JH bracelet (112, 142) determined for each target region.

[0067] Further provided is a method for preparing a jig holder (100) as defined herein comprising:

[0068] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;

[0069] - identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0070] - for each target region:

[0071] - determining from the three-dimensional medical image:

[0072] - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;

[0073] - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the J H bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial relation to the target region;

[0074] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146);

[0075] - constructing for each target region:

[0076] - a JH bracelet (112, 142) from the three-dimensional structure of a JH bracelet (112, 142); wherein the jig holder (100) comprises the JH bracelet (112, 142) constructed for each target region. Further provided is a method for preparing a jig holder (100) comprised in a system (1000) for assisting a surgical intervention on a bone of a subject comprising wherein:

[0077] - the jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:

[0078] - a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);

[0079] - a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;

[0080] - a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein:

[0081] - each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);

[0082] - the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (1 14DASM, 144DASM), co-operate to form the assembled state (1 14ASM, 144ASM) for a form-fit coupling by the JH passageway (116, 146) to the target region of the bone of the subject for the surgical intervention;

[0083] - the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) forms a circumferentially closed annular ring; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144);the method comprises: the method comprises:

[0084] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon; - identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0085] - for each target region:

[0086] - determining from the three-dimensional medical image:

[0087] - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;

[0088] - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial relation to the target region;

[0089] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146);

[0090] - constructing for each target region:

[0091] - a JH bracelet (112, 142) from the three-dimensional structure of a JH bracelet (112, 142); wherein the jig holder (100) comprises the JH bracelet (112, 142) constructed for each target region.

[0092] Further provided is a jig holder (100) obtained by a method for preparing a jig holder (100) as described herein.

[0093] Brief description of the drawings

[0094] The following description of the figures of specific embodiments of the invention is merely exemplary in nature and is not intended to limit the present teachings, their application or uses.

[0095] Fig. 1 illustrates a longitudinal cross-section through an exemplary jig holder (JH) bracelet as described herein.

[0096] Fig. 2A illustrates directions of the JH bracelet of FIG. 1 (Dis - distal; Prox - proximal). Fig. 2B illustrates further directions of the JH bracelet of FIG. 1 (Dis - distal; Prox - proximal; Ant - anterior; Post - posterior; Latieft - lateral left; Latnght - lateral right).

[0097] Fig. 3A illustrates a transverse cross-section through the JH bracelet of FIG. 1 at position B-B, wherein the JH bracelet body is in an assembled state.

[0098] Fig. 3B illustrates a transverse cross-section through the JH bracelet of FIG. 1 at position B-B, wherein the JH bracelet body is in a disassembled state.

[0099] Fig. 4A illustrates directions of the JH bracelet of FIGs. 3A / 3B (Dis - distal; Prox - proximal; peri - peripheral; c - central).

[0100] Fig. 4B illustrates further directions of the JH bracelet of FIGs. 3A / 3B (Dis - distal; Prox - proximal; Ant - anterior; Post - posterior; Latieft - lateral left; Latnght - lateral right).

[0101] Fig. 5 illustrates a JH bracelet of Fig. 1 further provided with a JH anti-rotation element.

[0102] Fig. 6 illustrates a longitudinal cross-section through an exemplary jig bracelet as described herein.

[0103] Fig. 7A illustrates directions of the jig bracelet of FIG. 6 (Dis - distal; Prox - proximal).

[0104] Fig. 7B illustrates further directions of the jig bracelet of FIG. 6 (Dis - distal; Prox - proximal;

[0105] Ant - anterior; Post - posterior; Latieft - lateral left; Latnght - lateral right).

[0106] Fig. 8A illustrates a transverse cross-section through the jig bracelet of FIG. 6 at position C-C, wherein the jig bracelet body is in an assembled state.

[0107] Fig. 8A illustrates a transverse cross-section through the jig bracelet of FIG. 6 at position C-C, wherein the jig bracelet body is in an disassembled state.

[0108] Fig. 9A illustrates directions of the jig bracelet of FIGs. 8A / 8B (Dis - distal; Prox - proximal; peri - peripheral; c - central).

[0109] Fig. 9B illustrates further directions of the jig bracelet of FIGs. 8A / 8B (Dis - distal; Prox - proximal; Ant - anterior; Post - posterior; Latieft - lateral left; Latnght - lateral right).

[0110] Fig. 10 illustrates a jig bracelet of Fig. 6 further provided with a jig-PE coupling element.

[0111] Fig. 11 illustrates a jig bracelet of Fig. 10 further provided with a JH anti-rotation element.

[0112] Fig. 12 illustrates a system comprising the jig bracelet of Fig. 10 coupled to the JH bracelet of Fig. 1. Fig. 13 illustrates a system comprising the jig bracelet of Fig. 11 coupled to the JH bracelet of Fig. 1.

[0113] Fig. 14 illustrates a system comprising a jig bracelet similar to that of Fig. 10 - wherein the jig-PE coupling element contains a bore - fixed spatial relation to the JH bracelet of Fig. 1.

[0114] Fig. 15 illustrates the system of Fig. 12 coupled to a dismountable prosthesis positioning tool.

[0115] Fig. 15A illustrates the prosthesis positioning tool of Fig. 15.

[0116] Fig. 16 illustrates the system of Fig. 12 coupled to a dismountable blade guide.

[0117] Fig. 16A illustrates the blade guide of Fig. 16.

[0118] Fig. 17 illustrates the system of Fig. 12 coupled to dismountable drill guide.

[0119] Fig. 17A illustrates the drill guide of Fig. 17.

[0120] Fig. 18 illustrates a longitudinal cross-section through an exemplary jig comprising a pair of JH bracelets.

[0121] Fig. 19A illustrates a transverse cross-section through the JH bracelet of FIG. 18 at position B2-B2, wherein the JH bracelet body is in an assembled state.

[0122] Fig. 19B illustrates a transverse cross-section through the JH bracelet of FIG. 18 at position B2-B2, wherein the JH bracelet body is in a disassembled state.

[0123] Fig. 20A illustrates a transverse cross-section through the JH bracelet of FIG. 18 at position B1-B1, wherein the JH bracelet body is in an assembled state.

[0124] Fig. 20B illustrates a transverse cross-section through the JH bracelet of FIG. 18 at position B1-B1, wherein the JH bracelet body is in a disassembled state.

[0125] Fig. 21 illustrates a longitudinal cross-section through an exemplary jig comprising a pair of jig bracelets.

[0126] Fig. 22A illustrates a transverse cross-section through the jig bracelet of FIG. 21 at position C2-C2, wherein the jig bracelet body is in an assembled state.

[0127] Fig. 22B illustrates a transverse cross-section through the jig bracelet of FIG. 21 at position C2-C2, wherein the jig bracelet body is in a disassembled state. Fig. 23A illustrates a transverse cross-section through the jig bracelet of FIG. 21 at position C1-C1, wherein the jig bracelet body is in an assembled state.

[0128] Fig. 24 illustrates a transverse cross-section through a system comprising a pair of jig bracelets coupled to a pair of JH bracelets, both jig bracelets mutually coupled with a gap between them.

[0129] Fig. 25 illustrates the system of Fig. 24, provided with a jig-PE coupling element, and a placement element that is a demountable blade guide.

[0130] Fig. 26 illustrates the system of Fig. 24, provided with a placement element that is a non- dismountable blade guide.

[0131] Fig. 27 illustrates a transverse cross-section through a system comprising a pair of jig bracelets coupled to a pair of JH bracelets, provided with a placement element that is a non-dismountable slotted guide.

[0132] Fig. 27A illustrates an anterior-posterior view of the slotted guide of Fig. 27.

[0133] Fig. 28 illustrates a transverse cross-section through a system comprising a pair of jig bracelets coupled to a pair of J H bracelets, each jig bracelet provided with a jig-PE coupling element for a placement element that is a support rod.

[0134] Fig. 29 illustrates the system of Fig. 28, wherein a placement element that is a support scaffold is disposed in the jig-PE coupling elements.

[0135] Fig. 30 illustrates a segment gap in a JH bracelet body segment and dimensional indicators.

[0136] Fig. 31 show boxplots of angular deviation (left) and height deviation (right) of a prosthesis implanted using the presently-described jig holder compared with a planned pose of the prosthesis. The directions set out in Figs. 2A, 2B, 4A, 4B, 7A, 7B, 9A and 9B apply mutatis mutandis to other figures disclosed herein. For example, the directions set out in Figs. 2A and 2B apply to Figs. 1 , 5, 12 to 18, 24 to 29. For example, the directions set out in Figs. 4A and 4B apply to Figs. 3A, 3B, 19A, 19B, 20A, 20B, 30. For example, the directions set out in Figs. 7A and 7B apply to Figs. 6, 10 to 17A, 21 , 24 to 29. The directions set out in Figs. 9A and 9B apply to Figs. 8A, 8B, 22, 22B, 23A, 23B. Description of embodiments

[0137] As used herein, the singular forms “a”, “an”, and “the” include both singular and plural referents unless the context clearly dictates otherwise.

[0138] The terms “comprising”, “comprises” and “comprised of” as used herein are synonymous with “including”, “includes”, “containing”, or “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms also encompass “constituted of”, “consists in”, “consisting of”, and “consists of’, and also the terms “consisting essentially of”, “consisting essentially in” and “consists essentially of’, which enjoy well-established meanings in patent terminology.

[0139] The recitation of numerical ranges by endpoints includes all intervening values between the lower and upper endpoints, as well as the recited endpoints. Intervening values may be integers or, where applicable, fractions, i.e., more broadly any real numbers such as any rational numbers. This applies to numerical ranges irrespective of whether they are introduced by the expression “from... to...” or the expression “between... and...” or another expression. Any numerical range recited herein is intended to include all subranges subsumed therein. For example, each sub-range between any stated value in a stated range and any other stated value in that stated range is also specifically disclosed. Each sub-range between any stated value in a stated range and either the lower endpoint or the upper endpoint of the stated range is also specifically disclosed. The stated value may be an isolated value or an endpoint of a range subsumed by or overlapping with the stated range. For example, for a stated range with lower endpoint L1 and upper endpoint U1 (i.e., stated range L1-LI1) and a stated sub-range nested within the stated range with lower endpoint L2 and upper endpoint U2 (i.e., stated sub-range L2-LI2), also specifically disclosed are the subranges L1-L2, L1-LI2, L2-U1 , and U2-LI1.

[0140] The terms “about” or “approximately” as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, are meant to encompass variations of and from the specified value, such as variations of + / -10% or less, preferably + / -5% or less, more preferably + / -1 % or less, and still more preferably + / -0.1 % or less of and from the specified value, insofar such variations are appropriate to perform in the disclosed invention. It is to be understood that the value to which the modifier “about” or “approximately” refers is itself also specifically, and preferably, disclosed.

[0141] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0142] Whereas the terms “one or more” or “at least one”, such as one or more members or at least one member of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members. In another example, “one or more” or “at least one” may refer to 1 , 2, 3, 4, 5, 6, 7 or more.

[0143] As used herein, the term “and / or” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone, B alone, C alone, A and B in combination, A and C in combination, B and C in combination, or A, B, and C in combination.

[0144] The discussion of the background to the invention herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge in any country as of the priority date of any of the claims.

[0145] Throughout this disclosure, various publications, patents and published patent specifications are referenced by an identifying citation. All documents cited in the present specification are hereby incorporated by reference in their entirety. In particular, the teachings or sections of such documents herein specifically referred to are incorporated by reference.

[0146] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the invention. When specific terms are defined in connection with a particular aspect of the invention or a particular embodiment of the invention, such connotation or meaning is meant to apply throughout this specification, i.e., also in the context of other aspects or embodiments of the invention, unless otherwise defined. In the following passages, different aspects or embodiments of the invention are defined in more detail. Each aspect or embodiment so defined may be combined with any other aspect(s) or embodiment(s) unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0147] Reference throughout this specification to “one embodiment”, “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0148] Similarly, it should be appreciated that in the description of illustrative embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects.

[0149] In the present description of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration only of specific embodiments in which the invention may be practiced. Parenthesized or emboldened reference numerals affixed to respective elements merely exemplify the elements by way of example, with which it is not intended to limit the respective elements. Unless otherwise indicated, all figures and drawings in this document are not to scale and are chosen for the purpose of illustrating different embodiments of the invention. In particular the dimensions of the various components are depicted in illustrative terms only, and no relationship between the dimensions of the various components should be inferred from the drawings, unless so indicated. The term “pose” as used herein in relation to an element (e.g. jig holder, jig bracelet, jig, jig bracelet, placement element) refers to a position and orientation of the element.

[0150] The term “readable” as used herein in relation to a position and / or orientation of an element with respect to another element means that the position and / or orientation of a first element with respect to a second element can be read by any means such as by reading-off a scale, by reading-off markings, and the like. The reading may be performed by optically e.g. by eye with or without magnification, and / or using a camera such as a digital camera.

[0151] The term ’’longitudinal” as used herein in relation to an element refers to a direction of the element along the longer side of the element. A central longitudinal axis (A-A’) is longitudinal axis along a midline of the element. For instance, central longitudinal axis (A- A’) of the JH bracelet may be coincide with a central longitudinal axis of the JH coupling region (which may be based in a cylindrical shape). A central longitudinal axis of the jig may coincide with a rotational axis of the jig when it is rotatable around the jig holder.

[0152] The term “transverse” as used herein refers to a direction perpendicular to the central longitudinal axis (A-A’).

[0153] The terms "distal", “distally” or "distal to" and "proximal", “proximally” or " proximal to" are used throughout the specification to refer to a direction of an element, and are terms generally understood in the field. Thus, "proximal", “proximally” or "proximal to" in relation to an element means towards the subject’s trunk. Conversely, "distal", “distally” or "distal to" in relation to an element means away from the subject’s trunk. For instance, a proximal end of a JH bracelet for a femur means an end of the JH bracelet towards the subject’s hip, and a distal end of the JH bracelet for the femur means an end of the JH bracelet the subject’s foot.

[0154] The “subject” as used herein refers to a person receiving the system i.e. in need of the surgical intervention. The “user” refers to a person or persons applying the system. The user may be a surgeon, in particular orthopedic surgeon, clinician, physician, or medical assistant.

[0155] The term “central” as used herein in relation to an element refers a direction towards a central longitudinal axis (A-A’) of the element. The direction is preferably perpendicular to the central longitudinal axis of the element. The term “peripheral” as used herein in relation to an element refers a direction away from a central longitudinal axis (A-A’) of the element. The direction is preferably perpendicular to the central longitudinal axis of the element.

[0156] The “anterior “(Ant) as used herein in relation to an element is a direction is a term known in the art, and refers to a direction of the element which when deployed in the subject is directed to the front of the subject. As explained elsewhere herein, the elements are definable in relation to a JH passageway having a shape complementary to a uniquely- shaped target region of the subject; consequently, the anterior direction of the element can be determined without being deployed in the subject.

[0157] The “posterior” (Post) as used herein in relation to an element is a direction is a term known in the art, and refers to a direction of the element which when deployed in the subject is directed to the rear of the subject. As explained elsewhere herein, the elements are definable in relation to a JH passageway having a shape complementary to a uniquely- shaped target region of the subject; consequently, the posterior direction of the element can be determined without being deployed in the subject.

[0158] The “Lateral” (Latieft, Latright) as used herein in relation to an element is a direction is a term known in the art, and refers to a direction of the element which when deployed in the subject is directed to side (left to right, or vice versa) of the subject. As explained elsewhere herein, the elements are definable in relation to a JH passageway having a shape complementary to a uniquely-shaped target region of the subject; consequently, the lateral direction of the element can be determined without being deployed in the subject.

[0159] Where a shape is described as being complementary to a uniquely-shaped target region of the subject, it is meant that the shape has a (three-dimension) surface contoured to reciprocally match contours of the target region. In other words, the shape is configured for a form-fitting attachment to the target region of the subject. In other words, the shape is configured for a form-fitting seating to the target region of the subject. Examples of directions are shown in FIGs. 2A, 2B, 4A, 4B, 7A, 7B, 9A, and 9B.

[0160] Provided herein is a system (1000) for assisting a surgical intervention on a bone of a subject.

[0161] The system (1000) comprises a jig holder (100), JH, comprising at least one JH bracelet (112, 142). Each JH bracelet (112, 142) comprises a longitudinal JH bracelet body (114, 144) (JH bracelet body (114, 144)). The JH bracelet body (114, 144) has a central longitudinal axis (A-A’). JH bracelet body (114, 144) has a proximal end at one longitudinal end, a distal end at an opposing longitudinal end. JH bracelet body (114, 144) has a central direction (radially) towards the central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’) (and having a ring shape).

[0162] Each JH bracelet (112, 142) further comprises a JH passageway (116, 146) disposed in the JH bracelet body (114, 144) between the proximal end and the distal end. JH passageway (116, 146) is a void space having a (three dimensional) shape complementary to a target region of the bone of the subject for the surgical intervention (thereby giving the JH bracelet body (114, 144) a closed ring shape).

[0163] Each JH bracelet (112, 142) further comprises a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for (repeatable) dismountable coupling to and alignment with a jig (200). The JH coupling region (118, 148) further comprises one or more JH anti-displacement elements (120, 120’; 150, 150’) to prevent displacement (e.g. by axial sliding) of the jig (200) coupled to the JH bracelet body (114, 144), relative to the JH bracelet body (114, 144).

[0164] Each JH bracelet body (114, 144) has an assembled state (1 14ASM , 144ASM) and disassembled state (1 14DASM, 144DASM).

[0165] Each JH bracelet body (114, 144) comprises a plurality (two or more) of JH bracelet body segments (114a, 114b; 144a, 144b).

[0166] The plurality of JH bracelet body segments (114a, 114b; 144a, 144b) of each JH bracelet body (114, 144) in the disassembled state (1 14DASM, 144DASM), co-operate to form the assembled state (114ASM, 144ASM) for a form-fit coupling by the JH passageway (116, 146) to the target region of the bone of the subject for the surgical intervention.

[0167] Each JH bracelet body segments (114a, 114b; 144a, 144b) is a longitudinal segment of the JH bracelet body (144).

[0168] Because the JH bracelet body (114, 144) has a disassembled state (1 14DASM, 144DASM) and an assembled state (1 14ASM, 144ASM) formed from longitudinal segments, it can access the target region in situ in disassembled state (1 14DASM, 144DASM) and subsequently attach (secured by coupling to the jig bracelet (212, 242)) to the target region in the assembled state (114ASM, 144ASM).

[0169] The bone of the subject does not have a uniform profile shape or position along its axial length i.e. is not cylindrical. Thus, the target region has a unique three-dimensional shape, wherever along an axial position of the bone the target is located. The JH passageway (116, 146) having a (three dimensional) shape complementary to the unique three- dimensional shape of the target region can locate uniquely along an axial length of the bone specifically at the target region. In other words, it can locate uniquely at only one pose along an axial length of the bone specifically at the target region. This allows the JH bracelet (112, 142) to be locked in both axial and rotational position at the target region using the natural geometry of bone as a motion stop, preventing sliding and rotation of the jig holder. This means that, using a stored medical image of the bone, the JH passageway (116, 146) can be shaped so that the JH bracelet (112, 142) form fits to the target region thereby preventing sliding and rotation of the JH bracelet (112, 142).

[0170] Because of the unique three-dimensional shape of the target region, the JH bracelet (112, 142) attached to the target region is accurately located on the bone i.e. at only one unique position and orientation. Hence it can be used as a pose-specific support, in particular for a jig bracelet (212, 242). The jig bracelet (212, 242) dismountably attached to the JH bracelet (112, 142) adopts one unique pose with respect to the bone, and (the JH bracelet (112, 142)) can support one or more placement elements (300) having a known pose in relation to the bone. The JH bracelet (112, 142) is hence a core element for surgical interventions requiring accurate placement of tools, instruments, implants (a plate, a screw, a prosthesis) and the like, e.g. for accurate bone cuts or for navigation markers.

[0171] The jig bracelet (212, 242) attached to the JH bracelet (112, 142) can hence be accurately positioned, allowing for placement of one or more placement elements (300) in known spatial (pose) relation to the bone. The JH bracelet (112, 142) is particularly useful where a bone is to be cut (in an osteometry procedure), and a location of the cut and an angle of the cut need to be planned and executed in order to complement an implant whose geometry is not necessarily patient specific. In such case, the JH bracelet (112, 142) may be used to align a blade guide with the required cutting location and angles.

[0172] Because the JH bracelet (112, 142) is locked in both axial and rotational position at the target region using the natural geometry of bone, there is an avoidance of drilling in order to mount a jig. Drilling is detrimental where the jig is located adjacent to a tumor to be resected. The adjacent bone, while free of tumor tissue, is commonly too close to the site of the cut to provide a sufficient volume of adjacent bone to support screws. It is known in the art that loads placed on a screw-mounted jig can cause the adjacent bone to fracture or split. Drilling can also increase a risk of a spreading of the cancer. The present JH bracelet (112, 142), by contrast, embraces the adjacent bone, thereby having an protective effect while simultaneously being locked in precise positional and rotational alignment with the bone for accurate alignment of a tool, instrument, or implant.

[0173] The jig holder (100), JH, comprises at least one JH bracelet (112, 142) configured for dismountable attachment to the target region of the bone of the subject. It has a longitudinal shape.

[0174] The JH bracelet (112, 142) dismountably attached to the target region of the bone of the subject, circumferentially surrounds the bone of the subject in the target region. Each JH bracelet has a ring shape.

[0175] The JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and a disassembled state (1 14DASM , 144DASM). The JH bracelet body (114, 144) comprises a JH passageway (146) and a JH coupling region (148) which are disposed in mutually fixed and non-adjustable spatial (pose) relation with each other in the assembled state (114ASM, 144ASM). The JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) is an annular ring, configured to encompass a circumference of the target region of the bone. The JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) has a longitudinal shape.

[0176] The JH bracelet body (114, 144) is divided along its length into the JH bracelet body segments (114a, 114b; 144a, 144b), wherein each the JH bracelet body segment (114a, 114b; 144a, 144b) is a longitudinal segment. Each JH bracelet body segment (114a, 114b; 144a, 144b) is longitudinal. Each JH bracelet body segments (114a, 114b; 144a, 144b) is a portion of the JH bracelet body (114, 144) running in a distal-proximal direction.

[0177] Each longitudinal segment is circumferentially incomplete. By circumferentially incomplete, it is meant that a transverse cross-section of the longitudinal segment is not a closed loop at any axial position.

[0178] The JH bracelet body segments (114a, 114b; 144a, 144b) in the disassembled state (114ASM, 144DASM) are configured to provide access to the JH passageway (116, 146) in a central direction for placement of the JH bracelet body segments (114a, 114b; 144a, 144b) around the target region to form the assembled state (114ASM, 144ASM).

[0179] Each and every JH bracelet body segments (144a; 144b) is (separately) dismountable from the JH bracelet body (114, 144).

[0180] The JH bracelet body segments (114a, 114b; 144a, 144b) in the assembled state (144ASM) form the JH passageway (116, 146) and also form the JH coupling region (118, 148).

[0181] Each JH bracelet body segment (144a; 144b) may be an essentially (±10 % by weight) equal portion of the JH bracelet body (114, 144), e.g. halve, third, quarter. It is within the scope of the invention that the JH bracelet body segments (114a, 114b; 144a, 144b) are unequal portions of the JH bracelet body (114, 144).

[0182] Where the JH bracelet body segments (114a, 114b; 144a, 144b) mutually interface, the interfacing surfaces may contact without interlocking, or may contact with interlocking. The interlocking where present restricts sliding of adjacent JH bracelet body segments (114a, 114b; 144a, 144b). The interlocking may be realized by complementary locating elements. Such elements are typically known in the art e.g. protrusions-recesses; castellated edges.

[0183] As mentioned elsewhere herein, the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) is an annular ring, configured to encompass a circumference of the target region of the bone.

[0184] The annular ring is divided into the JH bracelet body segments (114a, 114b; 144a, 144b), each JH bracelet body segment (114a, 114b; 144a, 144b) being a segment of the ring annulus. The JH bracelet body segments (114a, 114b; 144a, 144b) in the assembled state (114ASM, 144ASM) form the annular ring of the JH bracelet body (114, 144). JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) precludes access to the access to the JH passageway (116, 146) at least in a peripheral to central direction. The annular ring is preferably circumferentially complete. In other words, it is preferably circumferentially closed. By circumferentially complete or circumferentially closed in the assembled state (1 14ASM, 144ASM), it is meant that it is devoid of gaps, apertures, or windows. It is appreciated that interfaces between circumferentially adjacent JH bracelet body segment (114a, 114b; 144a, 144b) may include minimal gaps caused by manufacturing tolerances.

[0185] The JH passageway (116, 146) is contoured fully around its complete circumferential internal surface, thereby providing a circumferentially closed surface for a form-fit coupling to the target region of the bone of the subject for the surgical intervention. The circumferentially closed surface provides larger area for form-fit coupling to the target region. A longitudinal span (proximal-distal) of the JH passageway (116, 146) is preferably fully contoured for at least 75% of a total length of the JH passageway (116, 146)

[0186] Each JH bracelet body segment (114a, 114b; 144a, 144b) in the disassembled state (114DASM, 144DASM) contains a segment gap (114a’) allowing access to the JH passageway (116, 146) in a peripheral to central direction. For instance, the bone of the subject for the surgical intervention can be inserted and seated in the JH bracelet body segment (114a, 114b; 144a, 144b) ( / .e. JH passageway segment therein) by an approach of the bone in a peripheral to central direction or by an approach of the JH bracelet body segment in a peripheral to central direction. An exemplary segment gap (114a’) is shown in FIG. 30.

[0187] The segment gap (114a’) has a geometry of the missing JH bracelet body segment(s) (114a) that constitute(s) the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM). For each and every (all) JH bracelet body segment (114a, 114b; 144a, 144b), the segment gap (114a’) has a minimum outer circumference (Gcircum) that is at least 50% of the total outer circumference (Tcircum) of the JH bracelet body (114) in the assembled state (1 14ASM, 144ASM). The dimensions Gcircum and Tcircum are exemplarily set out in FIG. 30. The outer circumference size (Gcircum and Tcircum) is considered at any (all possible) longitudinal locations along the JH bracelet body segment (114a, 114b; 144a, 144b). The outer circumference size (Gcircum and Tcircum) is considered across a plane perpendicular to the JH central longitudinal axis (A-A’).

[0188] The segment gap (114a’) of defined size allows a mounting of the JH bracelet body (114, 144) segment-by-segment with a minimal disturbance to soft-tissue surrounding the target region of the bone of the subject. Because the segment gap (114a’) is at least 50% of the total outer circumference (Tcircum) of the JH bracelet body (114), each JH bracelet body segment (114a, 114b; 144a, 144b) can approach and be seating in the target region in a peripheral to central direction without obstruction caused by a too-narrow opening in the

[0189] JH bracelet body (114, 144). The segment-wise seating of each and every JH bracelet body segment (114a, 114b; 144a, 144b) allows a form-fitting attachment to an entire circumference of the target region of the bone in the assembled state (114ASM 144ASM). The inventors have found there is sufficient uniqueness and asymmetry in a bone region that the form-fitting attachment ( / .e. not requiring securing pins or bolts) using the entire circumference of the bone region / JH passageway does not present sufficient backlash for rotation or displacement. There is sufficient locking that the JH bracelet (112, 142) can be used to support one or more placement elements (300). By contrast, a U-shaped bone plate cannot be form-fitted to a target along the parallel edges of the “U” otherwise it could not slidably mounted to the bone in a peripheral to central direction. As a consequence, the U-shaped bone plate requires introduction of bone bolts or pins by drilling to prevent rotation / displacement.

[0190] The JH passageway (116, 146) has a (three dimensional) shape complementary to a target region of the bone of the subject. More in particular, when the JH bracelet body (114, 144) is in the assembled state (114ASM, 144ASM), the JH passageway (116, 146) has a (three dimensional) shape complementary to that of the target region of the bone of the subject. In other words, the JH passageway (116, 146) is configured for a form-fitting attachment to the target region of the bone of the subject. It is understood that the three dimensional shape of the target region refers to an exterior surface of the target region.

[0191] The JH passageway (116, 146) is a through-passageway. It is open both at its distal end and at its proximal end. The JH passageway (116, 146) is circumferentially closed. The circumferentially closed JH passageway (116, 146) is configured to provide a form-fit coupling to the target region of the bone of the subject for the surgical intervention.

[0192] A geometry of the passageway (116, 146) of the JH bracelet (112, 142) is preferably determined from one or more stored (3D) medical images comprising the target region of the bone of the subject.

[0193] The JH bracelet (112, 142) is configured such a pose (position and orientation) of JH passageway (116, 146) and a pose (position and orientation) of the JH coupling region (148) with respect to each other are known.

[0194] The JH bracelet (112, 142) is configured such a pose (position and orientation) of JH passageway (116, 146) and a pose (position and orientation) of the JH coupling region (148) with respect to each other cause a known or readable spatial (pose) alignment of a placement element (300) (e.g. blade guide, drill guide) with the target region of the bone of the subject. The JH passageway (116, 146) may have a pose (position and orientation) such that a distal end of a JH bracelet (112, 142) locates on the target region and causes a center of gravity of a transverse cross-section of a distal end of the co-operating JH bracelet (112, 142) to become aligned with a center of gravity of a transverse cross-section of the bone at a cutting location of the bone.

[0195] Alternatively, the JH passageway (116, 146) may have a pose (position and orientation) such that a distal end of a JH bracelet (112, 142) locates on the target region and causes a center of gravity of a transverse cross-section of a distal end of the co-operating JH bracelet (112, 142) to become offset with a center of gravity of a transverse cross-section of the bone at a cutting location of the bone.

[0196] The JH coupling region (118, 148) is a region of the J H bracelet body (114, 144) configured for dismountable coupling to or by a jig bracelet (212, 242) (more in particular of a jig coupling region (218, 248)) of a jig (200). The dismountable coupling is repeatable. The jig bracelet (212, 242) dismountably coupled to the JH bracelet body (114, 144) is disposed in fixed positional alignment with JH bracelet body (114, 144).

[0197] The jig bracelet (212, 242) dismountably coupled to the JH bracelet body (114, 144) may further be disposed in fixed (axial) rotational alignment with the JH bracelet body (114, 144). The jig bracelet (212, 242) dismountably coupled to the JH bracelet body (114, 144) may further be axially rotatable with respect to the JH bracelet body (114, 144).

[0198] The JH coupling region (118, 148) is at least a part of (preferably all of) an exterior annular circumferential surface of the JH bracelet body (114, 144). The JH coupling region (148) may or may not include at least a part of a distal end surface of the JH bracelet body (114, 144). The JH coupling region (118, 148) may or may not include at least a part of a proximal end surface of the JH bracelet body (114, 144).

[0199] The JH coupling region (118, 148) is preferably complementary to the jig coupling region (218, 248).

[0200] The JH coupling region (118, 148) comprises one or more JH anti-displacement elements (120, 120’) configured to prevent displacement (e.g. by axial sliding) of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), relative to the JH bracelet body (114, 144). The JH anti-displacement element may or may not further prevent rotation of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), for instance, around the JH central longitudinal axis (A-A’). Examples of a JH anti-displacement element (120, 120’) include a protrusion, a recess, a rail, at least a part of a distal end surface, at least a part of a proximal end surface. The JH anti-displacement element (120, 120’) is disposed in fixed (pose) relationship with the JH bracelet body (114, 144).

[0201] The JH coupling region (118, 148) may comprise one or more JH anti-rotation elements (124) configured to prevent rotation of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), relative to the JH bracelet body (114, 144), for instance, around the JH central longitudinal axis (A-A’). The JH anti-rotation element (124) may or may not further prevent displacement of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144). Examples of JH anti-rotation elements (124) include, a protrusion, a recess, exterior transverse profile of a polygon (e.g. pentagon, hexagon). The JH anti-rotation element (124) is disposed in fixed (pose) relationship with the JH bracelet body (114, 144)

[0202] The JH coupling region (118, 148) preferably comprises a shape of cylindrical outer surface. The JH coupling region (118, 148) preferably comprises a shape of cylindrical outer surface particularly when the JH bracelet body (114, 144) is axially rotatable with respect to the JH bracelet body (114, 144).

[0203] The JH bracelet (112, 142) is preferably produced in a patient-specific manner (e.g. milled or 3D printed) such that:

[0204] - the JH passageway (116, 146) is complementary to the target region; and

[0205] - the JH coupling region (118, 148) is in known spatial (pose) alignment with respect to the bone of the subject. More in particular, the JH coupling region (118, 148) is in known spatial alignment with respect to the bone of the subject when the JH bracelet (112, 142) is attached to the target region of the bone of the subject.

[0206] The JH bracelet (112, 142) is preferably produced in a patient-specific manner (e.g. milled, machined, molded, 3D printed) such that:

[0207] - the JH passageway (116, 146) is complementary to the target region; and

[0208] - the JH coupling region (118, 148) is complementary to a standard (non-subject- specific) jig passageway (216, 246);

[0209] - the at least one jig PE coupling element (226, 256) is in known spatial (pose) alignment with respect to the bone of the subject when the system (100) is in the super-assembled state and is attached to the target region of the bone.

[0210] The JH bracelet (112, 142), more in particular the JH bracelet body segments (114a, 114b; 144a, 144b), may be made from any suitable biocompatible material having requisite strength and stiffness. The material is sterilisable for instance by heat sterilisation, or chemical sterilisation (e.g. liquid or gas), or by irradiation, or by any other known technique, or a combination of two or more of these. The material is ideally resistant to deformation under sterilisation. Where material is deformed by sterilisation (e.g. shrinkage), the deformation is preferably minimised and / or predicable (e.g. by generating a calibration curve for the material). Examples of suitable materials include, stainless steel, chrome cobalt alloy, titanium, polymers based on polymethyl methacrylate (PMMA), polyetheretherketone (PEEK), polycarbonate (PC), Ultra-high-molecular-weight polyethylene (UHMWPE), polypropylene, polylactic acid, polyethylene terephthalate glycol. The JH bracelet (112, 142) multiple segments may be made from the same material or from different materials.

[0211] The JH bracelet (112, 142) and JH bracelet body segments (114a, 114b; 144a, 144b), more in particular the JH bracelet body segments (114a, 114b; 144a, 144b), are typically rigid (resistant to deformation under stress). The JH bracelet (112, 142) and JH bracelet body segments (114a, 114b; 144a, 144b) typically have a hard surface.

[0212] The system (1000) may further comprise a jig (200), wherein the jig (200) comprises at least one jig bracelet (212, 242).

[0213] The jig bracelet (212, 242) is configured for dismountable (repeatable) coupling to the JH bracelet (112, 142), in particular to the JH bracelet body (114, 144), in particular to the JH coupling region (118, 148).

[0214] Each jig bracelet (212, 242) comprises a jig bracelet body (214, 244) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A- A’) (and having a ring shape).

[0215] Each jig bracelet (212, 242) further comprises a jig passageway (216, 246) disposed in the jig bracelet body (214, 244) between the proximal end and the distal end (thereby giving the jig bracelet body (214, 244) a ring shape).

[0216] Each jig bracelet (212, 242) further comprises a jig coupling region (218, 248) comprising an interior annular circumferential surface of the jig passageway (216, 246) for (repeatable) dismountable coupling to and alignment with the JH coupling region (148) of the JH bracelet (112, 142).

[0217] The jig coupling region (218, 248) further comprises one or more jig anti-displacement elements (220, 220’; 250, 250’;) configured to prevent displacement (e.g. by axial sliding) of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), relative to the JH bracelet body (114, 144). The one or more jig anti-displacement elements (220, 220’) couple with the one or more JH anti-displacement elements (120, 120’) to effect prevention of displacement.

[0218] The jig coupling region (218, 248) is preferably complementary to the JH coupling region (118, 148).

[0219] Each jig bracelet body (214, 244) has an assembled state (244ASM) and a disassembled state (244DASM).

[0220] Each jig bracelet body (214, 244) comprises a plurality (two or more) of jig bracelet body segments (244a, 244b).

[0221] The plurality of jig bracelet body segments (214a, 214b; 244a, 244b) of each jig bracelet body (214, 244) in the disassembled state (214DASM, 244DASM), co-operate to form the assembled state (214ASM, 244ASM) for coupling to the JH coupling region (118, 148) of the JH bracelet (112, 142).

[0222] Further, the plurality of jig bracelet body segments (214a, 214b; 244a, 244b) of each jig bracelet body (214, 244) in the disassembled state (214DASM, 244DASM), co-operate to form the jig coupling region (218, 248) for coupling to the JH coupling region (118, 148) of the JH bracelet (112, 142).

[0223] Further, plurality of jig bracelet body segments (214a, 214b; 244a, 244b) of each jig bracelet body (214, 244) in the disassembled state (214DASM, 244DASM), co-operate to form the jig passageway (216, 246) for coupling to the JH coupling region (118, 148) of the JH bracelet (112, 142).

[0224] Further, the jig bracelet body segments (214a, 214b; 244a, 244b) in the assembled state (214ASM, 244ASM) cause retention of the JH bracelet body segments (114a, 114b; 144a, 144b) such that JH bracelet body segments (114a, 114b; 144a, 144b) maintain (are in) the assembled state (1 14ASM, 144ASM).

[0225] Each jig bracelet body segment (214a, 214b; 244a, 244b) is a longitudinal segment.

[0226] The jig bracelet body (214, 244) has an assembled state (214ASM, 244ASM) and a disassembled state (214DASM ,244DASM). The jig bracelet body (214, 244) comprises a jig passageway (246) and a JH coupling region (248) which are disposed in mutually fixed and non-adjustable spatial (pose) relation with each other in the assembled state (214ASM, 244ASM). The jig bracelet body (214, 244) in the assembled state (214ASM, 244ASM) is an annular ring, configured to encompass a circumference of the JH coupling region (148) of the JH bracelet body (114, 144).

[0227] The jig bracelet body (214, 244) is divided along its length into the jig bracelet body segments (214a, 214b; 244a, 244b), wherein each jig bracelet body segments (214a, 214b; 244a, 244b) is a longitudinal segment. Each longitudinal segment runs in a distal- proximal direction. Each longitudinal segment is circumferentially incomplete. By circumferentially incomplete it is meant that a transverse cross-section of the longitudinal segment is not a closed loop at any axial position.

[0228] The jig bracelet body segments (214a, 214b; 244a, 244b) in the disassembled state (214DASM, 244DASM) are configured to provide access to the jig passageway (216, 246) in a central direction for placement of the jig bracelet body segments (214a, 214b; 244a, 244b) around JH coupling region (118, 148) to form the assembled state (214ASM, 144ASM).

[0229] The jig bracelet body segments (214a, 214b; 244a, 244b) in the assembled state (244ASM) form the jig passageway (216, 446) and also form the jig coupling region (218, 248).

[0230] Each jig bracelet body segment (214a, 214b; 244a, 244b) may be an essentially (±10 % by weight) equal portion of the jig bracelet body (214, 244), e.g. halve, third, quarter. It is within the scope of the invention that the jig bracelet body segment (214a, 214b; 244a, 244b) are unequal portions of the jig bracelet body (214, 244).

[0231] Where the jig bracelet body segments (214a, 214b; 244a, 244b) mutually interface, the interfacing surfaces may contact without interlocking, or may contact with interlocking. The interlocking where present restricts sliding of adjacent jig bracelet body segments (214a, 214b; 244a, 244b). The interlocking may be realized by complementary locating elements. Such elements are typically known in the art e.g. protrusions-recesses; castellated edges.

[0232] The jig passageway (216, 246) has a (three dimensional) shape complementary to the JH coupling region (218, 148) of the JH bracelet body (114, 144). More in particular, when the jig bracelet body (214, 244) is in the assembled state (214ASM, 244ASM), the jig passageway (216, 246) has a (three dimensional) shape complementary to JH coupling region (118,148).

[0233] A geometry of the passageway (216, 246) of the JH bracelet (112, 142) is preferably determined from one or more stored (3D) medical images comprising the target region of the bone of the subject. The jig bracelet (212, 242) is configured such a pose (position and orientation) of jig passageway (216, 246) cause a known spatial (pose) alignment of a placement element (300) with respect to the target region of the bone of the subject.

[0234] The JH passageway (146) may have a pose (position and orientation) such that a distal end of a JH bracelet (112, 142) locates on the target region and causes a center of gravity of a transverse cross-section of a distal end of the co-operating JH bracelet (112, 142) to become align with a center of gravity of a transverse cross-section of the bone at a cutting location of the bone.

[0235] The jig bracelet (212, 242) is configured for dismountable coupling to the JH bracelet (112, 142) such that the jig bracelet (212, 242) disposed in fixed positional (but not necessarily rotational) alignment with respect the JH bracelet (112, 142). The dismountable coupling is repeatable.

[0236] By coupling the jig bracelet (212, 242) to the JH bracelet (112, 142) the JH bracelet body segments (114a, 114b; 144a, 144b) are retained by the jig bracelet (212, 242) such that JH bracelet body segments (114a, 114b; 144a, 144b) are in the assembled state (114ASM, 144ASM).

[0237] The jig bracelet (212, 242) dismountably coupled to the JH bracelet body (114, 144) may further be disposed in fixed (axial) rotational alignment with the JH bracelet body (114, 144).

[0238] The jig bracelet (212, 242) dismountably coupled to the JH bracelet body (114, 144) may further be axially rotatable with respect to the JH bracelet body (114, 144).

[0239] The system (1000) in a super-assembled state comprises the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) and jig bracelet body (214, 244) in the assembled state (214ASM, 244ASM), wherein JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) is nested (in a central direction) within the jig bracelet body (214, 244) in the assembled state (214ASM, 244ASM).

[0240] In super-assembled state is in practice typically realised when the system is deployed i.e. attached to the bone. However, the super-assembled state may be realized ex-vivo, e.g. for testing using a mimetic. The jig coupling region (218, 248) is a region of the jig bracelet body (114, 144) configured for dismountable coupling to the JH bracelet (112, 142), more in particular to the JH coupling region (118, 148). The dismountable coupling is repeatable.

[0241] The jig coupling region (218, 248) dismountably coupled to the JH coupling region (118, 148) is disposed in fixed positional (but not necessarily rotational) alignment with respect the JH coupling region (118, 148).

[0242] The jig coupling region (218, 248) comprises at least a part of (preferably all of) an interior annular circumferential surface of the jig passageway (216, 246). The jig coupling region (218, 248) may or may not include at least a part of a distal end surface of the jig passageway (216, 246). The jig coupling region (218, 248) may or may not include at least a part of a proximal end surface of the jig passageway (216, 246).

[0243] The jig coupling region (218, 248) is preferably complementary to the JH coupling region (118, 148).

[0244] The jig coupling region (218, 248) comprises one or more jig anti-displacement elements (220, 220’; 250, 250’) configured to prevent displacement (e.g. by axial sliding) of jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), relative to the JH bracelet body (114, 144). The jig anti-displacement element may or may not further prevent rotation of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), for instance, around the JH central longitudinal axis (A-A’). Examples of a jig anti-displacement element (220, 220’; 250, 250’) include a protrusion, a recess, a rail, at least a part of a distal end surface, at least a part of a proximal end surface. The jig anti-displacement element (220, 220’; 250, 250’) is disposed in fixed (pose) relationship with the jig bracelet body (114, 144)

[0245] The jig coupling region (218, 248) may comprise one or more JH anti-rotation elements (224, 254) configured to prevent rotation of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144), relative to the JH bracelet body (224, 254), for instance, around the JH central longitudinal axis (A-A’). The jig anti-rotation element (224, 254) may or may not further prevent displacement of the jig bracelet (212, 242) coupled to the JH bracelet body (114, 144). Examples of jig anti-rotation elements (224, 254) include, a protrusion, a recess, exterior transverse profile of a polygon (e.g. pentagon, hexagon). The jig antirotation element (224, 254) is disposed in fixed (pose) relationship with the jig bracelet body (114, 144). The jig coupling region (218, 248) preferably comprises a shape complementary to a cylinder. The jig coupling region (218, 248) preferably comprises a shape complementary to a cylinder particularly when the JH bracelet body (114, 144) is axially rotatable with respect to the JH bracelet body (114, 144).

[0246] Where the jig bracelet (212, 242) dismountably coupled to the JH bracelet body (114, 144) is axially rotatable with respect to the JH bracelet body (114, 144), a locking mechanism may be provided for lockable rotatable adjustment the jig bracelet (212, 242) with respect to the JH bracelet body (114, 144). The locking mechanism is preferably disposed on the jig bracelet (212, 242). The locking mechanism may utilize friction and / or co-operating stop members (e.g. lockable indexed angles).

[0247] The jig bracelet (212, 242) may comprise one or more elements for coupling to a placement element (300), i.e. one or more jig-PE coupling elements (226, 256). As explained elsewhere herein, a placement element (300) such as a tool guide, a drill guide, a support guide is useful during the surgical intervention whose pose with respect to the bone needs to be known, and whose pose with respect to the bone is determined by the JH bracelet (112, 142) and jig bracelet (212, 242).

[0248] The jig-PE coupling element (226, 256) co-operates with the placement element (300) such that the position and / or orientation of the placement element (300) is in known or readable relation to the jig bracelet body (214, 244), or jig bracelet (212, 242) and ultimately to the target region and to the bone.

[0249] A jig-PE coupling element (226, 256) is typically disposed in fixed relation to the jig bracelet body (214, 244) (in the assembled state (214ASM, 144ASM)). An example of jig-PE coupling element (226, 256) includes a protrusion, a threaded protrusion, an indentation, an aperture, a notch, a rail, a groove, a slot, a bore, a threaded bore.

[0250] The jig-PE coupling element (226, 256) co-operates with a complementary coupling element (326) on the placement element (300) i.e. with a PE-jig coupling element (326). An example of PE-jig coupling element (326) includes protrusion, a threaded protrusion, an indentation, an aperture, a notch, a rail, a groove, a slot, a bore, a threaded bore.

[0251] The mutual coupling between the jig-PE coupling element (226, 256) and the PE-jig coupling element (326) may result in a fixed (non-adjustable) alignment of the jig-PE coupling element (226, 256) and the PE-jig coupling element (326). This typically rises when both PE-jig coupling element (326) and jig-PE coupling element (226, 256) locate at only one pose. For example, a pair of protrusions may couple with a pair of an indentations, thereby prevent movement both displacement and rotation.

[0252] The mutual coupling between the jig-PE coupling element (226, 256) and the PE-jig coupling element (326) may result in adjustable alignment of the jig-PE coupling element (226, 256) and the PE-jig coupling element (326). For instance, the jig-PE coupling element (226, 256) and the PE-jig coupling element (326) may be mutually rotatable with respect to each other (but not mutually slidable). A scale may be provided to read off an extent of the adjustment. For example, a circumferential rail may be disposed on an exterior circumferential surface of the jig bracelet body (214, 244) that couples with a groove provided in an inner cylindrical surface of the placement element. The coupling of the rail-groove allows rotational movement but prevents displacement.

[0253] The jig bracelet (212) may comprise one or more elements for coupling to a second jig bracelet (242), i.e. one or more jig-SJ coupling element (228). Exemplary jig-SJ coupling element (228) is shown in FIGs. 24 to 26.

[0254] The jig-SJ coupling element (228) co-operates with the second jig bracelet (242) in order to increase stability of the system (1000).

[0255] A jig-SJ coupling element (228) is typically disposed in fixed relation to the jig bracelet body (214) (in the assembled state (214ASM). An example of jig-SJ coupling element (228) includes a protrusion, a threaded protrusion, an indentation, an aperture, a notch, a rail, a groove, a slot, a bore, a threaded bore.

[0256] The jig-SJ coupling element (228) co-operates with a complementary coupling element (326) on the second jig bracelet (242) i.e. with a SJ-jig coupling element (258). An example of a SJ-jig coupling element (258) includes protrusion, a threaded protrusion, an indentation, an aperture, a notch, a rail, a groove, a slot, a bore, a threaded bore. SJ-jig coupling element (258) is shown in FIGs. 24 to 26.

[0257] The mutual coupling between the jig-SJ coupling element (228) and the SJ-jig coupling element (258) may result in a fixed (non-adjustable) alignment of jig-SJ coupling element (228) and the SJ-jig coupling element (258). This typically rises when both jig-SJ coupling element (228) and the SJ-jig coupling element (258) locate at only one pose. For example, a pair of protrusions may couple with a pair of an indentations, thereby prevent movement both displacement and rotation. The mutual coupling between the jig-SJ coupling element (228) and the SJ-jig coupling element (258) may result in adjustable alignment of the jig-SJ coupling element (228) and the SJ-jig coupling element (258). For instance, jig-SJ coupling element (228) and the SJ- jig coupling element (258) may be mutually rotatable with respect to each other (but not mutually slidable). A scale may be provided to read off an extent of the adjustment. For example, a circumferential rail may be disposed on an exterior circumferential surface of the jig bracelet body (214) that couples with a groove provided in an inner cylindrical surface of the second jig (244). The coupling of the rail-groove allows rotational movement but prevents displacement.

[0258] The jig-SJ coupling element (228) of a jig bracelet (212) may also function as a jig-PE coupling element (226). For example, when a second jig bracelet (242) is not attached via a jig-SJ coupling element (228) - SJ-jig coupling element (258) mutual coupling to the jig bracelet (212), the jig-PE coupling element (226) of the jig bracelet (212) may function as a jig-PE coupling element (226) for coupling to a placement element (300).

[0259] By coupling the jig bracelet (212, 242) to the JH bracelet (112, 142), the JH bracelet body segments (114a, 114b; 144a, 144b) are retained by the jig bracelet (212, 242) such that JH bracelet body segments (114a, 114b; 144a, 144b) are in the assembled state (114ASM, 144ASM).

[0260] The coupling of the jig bracelet (212, 242) to the JH bracelet (112, 142) may or may not be accompanied by a clamping force in a central direction, introducing by the jig bracelet (212, 242) which and which is transferred to the JH bracelet body segments (114a, 114b; 144a, 144b).

[0261] The coupling the jig bracelet (212, 242) to the JH bracelet (112, 142) may be accompanied by a clamping force in a central direction, introducing by the jig bracelet (212, 242) which and which is transferred to the JH bracelet body segments (114a, 114b; 144a, 144b). The clamping force by the jig bracelet (212, 242) may apply a force in a central direction from the JH bracelet body segments (114a, 114b; 144a, 144b) to the target region; the clamping force increases frictional contact between the JH bracelet (112, 142) and the target region, thereby increasing security of fit.

[0262] Each jig bracelet body segment (214a, 214b; 244a, 244b)) may comprise one or more fixture elements (e.g. open bore, threaded bore) for attaching the respective jig bracelet body segments (214a, 214b or 244a, 244b) to each other using one or more fasteners. The fasteners may be threaded fasteners (e.g. bolt, screw). Adjustment (e.g. by rotation) of one or more threaded fasteners may not or may change (increases or decreases) a force of clamping applied by the respective jig bracelet body segments (214a, 214b or 244a, 244b) to JH coupling region (118, 148) of the JH bracelet (112, 142).

[0263] The coupling of the jig bracelet (212, 242) to the JH bracelet (112, 142) may not be accompanied by a significant clamping force in a central direction, introducing by the jig bracelet (212, 242) which and which is transferred to the JH bracelet body segments (114a, 114b; 144a, 144b) and to the bone of the target region; in such case the J H bracelet body segments (114a, 114b; 144a, 144b) are retained by the jig bracelet (212, 242) such that JH bracelet body segments (114a, 114b; 144a, 144b) are in the assembled state (1 14ASM, 144ASM).

[0264] The jig bracelet (212, 242), more in particular the jig bracelet body segments (214a, 214b; 244a, 244b), may be made manufactured by an suitable process, for instance, additive manufacturing (3D printing), moulding, milling, laser cutting, metal forming (bending, punching, flanging, blanking).

[0265] The jig bracelet (212, 242), more in particular the jig bracelet body segments (214a, 214b; 244a, 244b), may be made from any suitable biocompatible material having requisite strength and stiffness. The material is sterilisable for instance by heat sterilisation, or chemical sterilisation (e.g. liquid or gas), or by irradiation, or by any other known technique, or a combination of two or more of these. The material is ideally resistant to deformation under sterilisation. Where material is deformed by sterilisation (e.g. shrinkage), the deformation is preferably minimised and / or predicable (e.g. by generating a calibration curve for the material). Examples of suitable materials include stainless steel, chrome cobalt alloy, titanium, polymers based on polymethyl methacrylate (PMMA), polyetheretherketone (PEEK), polycarbonate (PC), Ultra-high-molecular-weight polyethylene (UHMWPE), polypropylene, polylactic acid, polyethylene terephthalate glycol. Where the jig bracelet (212, 242) comprises multiple parts, the multiple parts may be made from the same material or from different materials.

[0266] The jig bracelet (212, 242) and jig bracelet body segments (214a, 214b; 244a, 244b), more in particular the jig bracelet body segments (214a, 214b; 244a, 244b), are typically rigid (resistant to deformation under stress). The jig bracelet (212, 242) and jig bracelet body segments (214a, 214b; 244a, 244b), typically have a hard surface. A placement element (300) is an (mechanical or electronic or electromechanical) element useful during the surgical intervention whose pose with respect to the bone needs to be known or is readable, and whose pose with respect to the bone is determined by the JH bracelet (112, 142) and jig bracelet (212, 242).

[0267] The placement element (300) is disposed in known or readable relation with the jig bracelet (212, 242) such that the position and / or orientation of the placement element (300) is in known or readable relation to the jig bracelet (212, 242) or jig bracelet body (214, 244), and ultimately to the target region and to the bone.

[0268] The placement element (300) may be (repeatably) detachable from the jig bracelet (212, 242). Where the placement element is detachable from the jig bracelet (212, 242), placement element (300) detachably couples to a coupling element for a placement element, jig PE coupling element (226), disposed on the JH bracelet body (114, 144). The jig-PE coupling element (226, 256) is disposed in fixed relation to the JH bracelet body (114, 144). The facility for repeatably detachable may be achieved, using any suitable means. For instance, the jig PE coupling element (226) may be multi-segmented; disassembly of the multi-segments allows the jig PE coupling element (226) to be dismounted from the jig bracelet (212, 242); assembly of the multi-segments allows the jig PE coupling element (226) to be mounted on the jig bracelet (212, 242).

[0269] The placement element (300) may be non-detachable ( / .e. is formed part of or is permanently attached to) from the jig bracelet (212, 242).

[0270] The placement element (300) may be adjustable with respect to the jig bracelet (212, 242). For instance, the placement element (300) may be rotatable (around the central longitudinal axis (A-A’)) with respect to the jig bracelet (212, 242).

[0271] The placement element (300) may be non-adjustable with respect to the jig bracelet (212, 242). For instance, the placement element (300) may be in fixed rotational and positional (displaceable) with respect to the jig bracelet (212, 242).

[0272] The placement element (300) may comprise one or more elements for coupling to the jig (200), i.e. one or more PE-jig coupling elements (326).

[0273] The placement element (300) co-operates with the jig-PE coupling element (226, 256) such that the position and / or orientation of the placement element (300) is in known or readable relation to the jig bracelet body (214, 244), or jig bracelet (212, 242) and ultimately to the target region and to the bone. A PE-jig coupling element (326) is typically disposed in fixed relation to the placement element (300). An example of PE-jig coupling element (326) includes a protrusion, a threaded protrusion, an indentation, an aperture, a notch, a rail, a groove, a slot, a bore, a threaded bore.

[0274] The PE-jig coupling element (326) co-operates with a complementary coupling element (226, 256) on the jig bracelet (212, 242) i.e. with a jig-PE coupling element (226, 256). An example of jig-PE coupling element (226, 256) includes a protrusion, a threaded protrusion, an indentation, an aperture, a notch, a rail, a groove, a slot, a bore, a threaded bore..

[0275] The mutual coupling between the PE-jig coupling element (326) and the jig-PE coupling element (226, 256) may result in the fixed (non-adjustable) alignment of the jig-PE coupling element (226, 256) and the PE-jig coupling element (326). This typically rises when both PE-jig coupling element (326) and jig-PE coupling element (226, 256) locate at only one pose. For example, a pair of protrusions may couple with a pair of an indentations, thereby prevent movement both displacement and rotation.

[0276] The mutual coupling between the PE-jig coupling element (326) and the jig-PE coupling element (226, 256) may result in the adjustable alignment of the jig-PE coupling element (226, 256) and the PE-jig coupling element (326). For instance, the jig-PE coupling element (226, 256) and the PE-jig coupling element (326) may be mutually rotatable with respect to each other (but not mutually slidable). A scale may be provided to read off an extent of the adjustment. For example, a circumferential rail may be disposed on an exterior circumferential surface of the jig bracelet body (214, 244) that couples with a groove provided in an inner cylindrical surface of the placement element. The couple of the rail-groove allows rotational movement but prevent displacement.

[0277] The placement element (300) may be made manufactured by an suitable process, for instance, involving additive manufacturing (3D printing), moulding, milling, laser cutting, metal forming (bending, punching, flanging, blanking).

[0278] The placement element (300) may be made from any suitable biocompatible material having requisite strength and stiffness. The material is sterilisable for instance by heat sterilisation, or chemical sterilisation (e.g. liquid or gas), or by irradiation, or by any other known technique, or a combination of two or more of these. The material is ideally resistant to deformation under sterilisation. Where material is deformed by sterilisation (e.g. shrinkage), the deformation is preferably minimised and / or predicable (e.g. by generating a calibration curve for the material). Examples of suitable materials include stainless steel, chrome cobalt alloy, titanium, polymers based on polymethyl methacrylate (PMMA), polyetheretherketone (PEEK), polycarbonate (PC), Ultra-high-molecular-weight polyethylene (UHMWPE), polypropylene, polylactic acid, polyethylene terephthalate glycol. Where the placement element (300) comprises multiple parts, the multiple parts may be made from the same material or from different materials.

[0279] The placement element may be a guide for a tool - such as a cutting blade, drill, router, or laser.

[0280] The placement element may be a guide for an implant - such as a screw, plate or pin.

[0281] The placement element may be a part of a support scaffold - such as a rod, an extension rod.

[0282] The placement element may be a blade shield.

[0283] The placement element may be a navigation marker (e.g. a body having a camera- readable three-dimensional geometry such as sphere, cube, diamond, pyramid; having a transponder that emits an electromagnetic signal that is detectable by a transponder reader)

[0284] The placement element (300) may be a prosthesis positioning tool (320, e.g. FIGs. 15, 15A), blade guide (310, 310’ e.g. FIGs. 16, 16A, 25, 26), a drill guide, a drill guide for introduction of an axial (longitudinal) bore along the medulla of the bone, a drill guide (330 e.g. FIG. 17 and 17A) for introduction of a transverse bore into the compact bone layer of the bone, an implant guide, a blade shield guide (320 e.g. FIG. 16A), a slotted guide (340 e.g. FIG. 27, FIG. 27A), a support rod (350, 350’ e.g. FIG. 29), a support scaffold (352 e.g. FIG. 29).

[0285] The placement element (300) may be a blade guide (310, 310’). Exemplary blade guides are shown in FIGs. 16, 16A, 25 and 26.

[0286] The blade guide (310) may be dismountable (e.g. FIGs. 16, 16A, 25) from a jig bracelet body (214, 244). The dismountable blade guide (300) co-operates with the at least one jig- PE coupling element (226, 256). More in particular, the at least one blade guide (310) PE- jig coupling element (326) co-operates with the at least one jig-PE coupling element (226, 256). The blade guide (310) may be non-dismountable (e.g. FIG. 26) from a jig bracelet body (214, 244) i.e. non-dismountable in the assembled state (214ASM, 244ASM) of the jig bracelet body (214, 244).

[0287] The blade guide (310) may rotatable (and not displaceable) around the central longitudinal axis (A-A’).

[0288] The blade guide (310) may have a fixed (non-adjustable) pose in relation to the jig bracelet body (214, 244).

[0289] The drill guide (330) typically comprises a drill guide body (332) disposed proximal of or distal of the JH bracelet body (114, 144). The drill guide body (332) is disposed with a plurality of open-ended guide holes (334). Each guide hole (334) is configured to guide a drill bit into a space axially proximal or distal of the JH bracelet body (144). In other words, the blade

[0290] The blade guide (310, 310’) typically comprises a blade guide body disposed proximal of or distal of the JH bracelet body (114, 144). The blade guide body is disposed with a blade passage (312) with The blade passage (312) is configured to guide a blade into a space axially proximal or distal of the JH bracelet body (144). In other words, the blade passage disposed is configured to guide a blade into a space axially clear (devoid) of the J H bracelet body (144).

[0291] The blade guide (310, 310’) may be configured to introduce a cut into the bone perpendicular to the bone longitudinal axis. The blade guide (310, 310’) may be configured to introduce a cut into the bone oblique to the bone longitudinal axis.

[0292] The pose of the blade passage (312) is known (e.g. fixed or readable) with respect to the blade guide (310) PE-jig coupling element (326).

[0293] The blade (for insertion into the blade guide) is longitudinal and has a leading end (towards the practitioner) end and trailing end (away from the practitioner).

[0294] The placement element (300) that is a blade guide (310) may include a blade shield (320, e.g. FIGs. 16A).

[0295] The blade shield (320) is configured to protect soft tissue damage by the blade leading end.

[0296] The blade shield (320) is configured to limit (stop) movement of the blade leading end. The blade shield (320) is preferably configured to limit (stop) movement of the blade leading end such that movement of the blade past the jig bracelet body (214, 244) is prevented. The blade shield (320) is preferably configured to limit (stop) movement of the blade leading end such that movement of the blade into soft tissue is prevented. The blade shield (320) typically has a body positioned for striking contact with the blade leading end of the blade, and of sufficient strength to withstand impact of the blade leading without deformation.

[0297] According to one aspect, the blade shield (320) is disposed on a fictive cylinder centred on and perpendicular to the central longitudinal axis (A-A’), and wherein diametrically opposed to the blade shield on the fictive cylinder is the blade passage of the blade guide.

[0298] The placement element (300) may be a prosthesis positioning tool (320). An exemplary prosthesis positioning tool is shown in FIGs. 15 and 15A .

[0299] The prosthesis positioning tool (320) is a prosthesis alignment guide. It is configured to place the prosthesis in known spatial relation to the jig bracelet (212, 244) (and hence target, and hence bone of the subject). The known spatial relation (pose) is one that ensures that the prosthesis is placed in an optimum anatomical pose with respect to the bone (e.g. is oriented in optimum axial, coronal, sagittal, and rotational planes). The known spatial relation I optimum anatomical pose may be determined from the three-dimensional medical image of the bone of the subject.

[0300] The prosthesis positioning tool (320) comprises a prosthesis positioning tool coupling, a PPT coupling element (324) configured for coupling to the prosthesis. The PPT coupling element (324) preferably restricts movement (e.g. pitch and yaw) of the prosthesis coupled to the PPT coupling element (324) with respect to the PPT coupling element (324), while allowing sliding only (and optionally axial rotation (roll) only) of the prosthesis with respect to the PPT coupling element (324). With the coupling tool, the user (e.g. surgeon) can guide the prosthesis approach (by sliding motion) to the cut bone at a known angle (e.g. pitch and yaw). The surgical outcome is improved (e.g. less post-operative adjustment) because the implanted prosthesis pose as determined during the surgical planning is more accurately transferred to the actual bone of the subject.

[0301] The prosthesis positioning tool (320) may be dismountable (e.g. FIGs. 15, 15A) from a jig bracelet body (214, 244). The dismountable prosthesis positioning tool (320) co-operates with the at least one jig-PE coupling element (226, 256). More in particular, the at least one prosthesis positioning tool (320) PE-jig coupling element (326) co-operates with the at least one jig-PE coupling element (226, 256). The prosthesis positioning tool (320) may be non-dismountable from a jig bracelet body (214, 244) i.e. non-dismountable in the assembled state (214ASM, 244ASM) of the jig bracelet body (214, 244).

[0302] The prosthesis positioning tool (320) may rotatable (and not displaceable) around the central longitudinal axis (A-A’).

[0303] The prosthesis positioning tool (320) may have a fixed (non-adjustable) pose in relation to the jig bracelet body (214, 244).

[0304] The prosthesis positioning tool (320) typically comprises a prosthesis positioning tool body (322) disposed proximal of or distal of the JH bracelet body (114, 144). The prosthesis positioning tool body (322) is disposed with the PPT coupling element (324). The PPT coupling element (324) may be, for instance, a bore of the prosthesis positioning tool body (322)

[0305] The pose of PPT coupling element (324) is known (e.g. fixed or readable) with respect to the prosthesis positioning tool (320) PE-jig coupling element (326).

[0306] The placement element (300) may be a drill guide (330). An exemplary drill guide (330) is shown in FIGs. 17 and 17A configured for introducing transverse bore holes. It is understood that a drill guide may alternatively be configured for introducing a bore hole along a medulla of the bone.

[0307] The drill guide (330) may be dismountable (e.g. FIGs. 17, 17A) from a jig bracelet body (214, 244). The dismountable drill guide (330) co-operates with the at least one jig-PE coupling element (226, 256). More in particular, the at least one drill guide (330) PE-jig coupling element (326) co-operates with the at least one jig-PE coupling element (226, 256).

[0308] The drill guide (330) may be non-dismountable from a jig bracelet body (214, 244) i.e. non- dismountable in the assembled state (214ASM, 244ASM) of the jig bracelet body (214, 244).

[0309] The drill guide (330) may rotatable (and not displaceable) around the central longitudinal axis (A-A’).

[0310] The drill guide (330) may have a fixed (non-adjustable) pose in relation to the jig bracelet body (214, 244).

[0311] The drill guide (330) typically comprises a drill guide body (322) disposed proximal of or distal of the JH bracelet body (114, 144). The drill guide body (322) is disposed with a plurality of open-ended guide holes (324). Each guide hole (324) is configured to guide a drill bit into a space axially proximal or distal of the JH bracelet body (144). In other words, the blade passage disposed is configured to guide a drill bit into a space axially clear (devoid) of the JH bracelet body (144).

[0312] The pose of each guide hole (324) is known (e.g. fixed or readable) with respect to the drill guide (330) PE-jig coupling element (326).

[0313] The target region of the bone is a portion of a bone extending around a circumference of the bone having an axial length. The axial length of the target region is typically greater than ~1 cm, and typically less than -20% of a full axial length of the bone. The target region is typically within a diaphysis of the bone, however, it may equally be within a metaphysis or epiphysis of the bone.

[0314] The target region is disposed next to (e.g. adjacent to, separated by a spacing gap from) a position on the bone where a surgical intervention is to take place in the subject, such as a cut or an excavation.

[0315] The target region is typically identified by the medical practitioner based on one or more three dimensional medical images of the bone of the subject.

[0316] The bone may be any bone of the subject in need of the surgical intervention. Examples include, but are not limited to femur, tibia, fibula, humerus, radius, ulna.

[0317] The surgical intervention may be any performed on the bone of the subject. Typically, the surgical intervention is one that requires a placement of a tool, instrument, implant (prosthetic or bone), support, scaffold or the like in known positional relation to the bone. Examples of surgical interventions include single or double osteotomy of a bone; alignment of a reconstruction prosthesis or bone, alignment of an implant.

[0318] The three-dimensional medical image may be any that shows a three-dimensional shape of an outer surface of at least a part of the bone of the subject that includes the target region. Examples of suitable medical imaging methods include CT (computed tomography) scan, MRI (magnetic resonance imaging) scan, PET (positron emission tomography) scan. A scan resolution is ideally 1.5 mm or better.

[0319] From the stored three dimensional image, a three dimensional shape of the JH passageway (116, 146) can be determined which has a shape complementary to that of the target region of the bone of the subject. The pose of the JH coupling region (118, 148) can be determined, based on a knowledge of the pose of the placement element (300). For instance, if the placement element (300) is a blade required to introduce a transverse cut, a pose of JH coupling region (118, 148) with respect to a pose of the JH passageway (116, 146) can be selected which provides a pose of the placement element (300) such that the cut is at a desired angle and location.

[0320] Methods to determine the shape and pose of the JH passageway (116, 146) relative to the JH coupling region (118, 148) are known in the art, for instance, Marc-Olivier Gauci, Patient-specific guides in orthopedic surgery, 2022, Orthopaedics and Traumatology: Surgery&Research. DOI Methods to determine the shape and pose of the JH passageway (116, 146) relative to the JH coupling region (118, 148) are performed offline e.g. using one or more stored medical images.

[0321] Once the desired pose of the JH coupling region (118, 148) and the desired pose of the JH passageway (116, 146) are known, a three dimensional model (e.g. CAD model) may be created of the JH bracelet (112, 142). The JH bracelet (112, 142) three dimensional model is divided into two or more JH bracelet body segments (114a, 114b; 144a, 144b) that are longitudinal to allow access to the JH passageway (116, 146) in a central direction for placement of the JH bracelet body segments (114a, 114b; 144a, 144b) around the target region to form the assembled state (114ASM, 144ASM).

[0322] The JH bracelet (112, 142) three dimensional model is turned into a work piece e.g. by additive manufacturing (3D printing), by machining, by milling, and the like.

[0323] The jig holder (100) may comprises more than one (e.g. 2, 3, 4) of the JH bracelets (112, 142) described herein, each configured for attachment to different target regions of the same bone of the subject for the intervention. More than one JH bracelet (112, 142) allows support of placement elements at different target regions. For instance, where a tumor is to be excised by removal of a portion of bone, the distance and pose of the bone portions flanking the removed bone portion can be maintained by a scaffold supported by a pair of the JH bracelets (112, 142) flanking the site of the bone removal allowing, the scaffold to span the site of the bone removal.

[0324] According to one aspect, the jig holder (100), JH, comprises a pair of the JH bracelets (112, 142) wherein each JH passageway (116 or 146) of the pair of JH passageways (116, 146) is configured for attachment to a different target region of the same bone of the subject for the intervention. According to one aspect, the jig holder (100), JH, comprises a pair of the JH bracelets (112, 142) wherein each JH bracelet (112, 142) comprises:

[0325] - the longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’) (and having a ring shape);

[0326] - the JH passageway (116, 146) disposed in the JH bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the intervention (thereby giving each JH bracelet body (114, 144) a ring shape);

[0327] - the JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144). The JH coupling region (118, 148) further comprises one or more JH anti-displacement elements (120, 120’; 150, 150’) to prevent displacement (e.g. by axial sliding) of the JH bracelet body (114, 144) relative to the jig bracelet body (214, 244) coupled to the JH bracelet body (114, 144). wherein each JH bracelet body (114, 144) has the assembled state (144ASM) and the disassembled state (144DASM), wherein:

[0328] - each JH bracelet body (114, 144) comprising the plurality (two or more) of JH bracelet body segments (114a, 144b; 114a, 144b);

[0329] - the plurality of JH bracelet body segments (114a, 144b; 114a, 144b) of each JH bracelet body (114, 144) in the disassembled state (1 14DASM; 144DASM), co-operate to form the assembled state (1 14ASM; 144ASM) for coupling to the target region of the bone of the subject for the surgical intervention.

[0330] - each JH bracelet body segment (114a, 144b; 114a, 144b) is a longitudinal segment.

[0331] Each JH bracelet (112, 142) of the pair of JH bracelets (112, 142) is configured for attachment to a different target region of the same bone of the subject for the intervention.

[0332] More in particular, each JH passageway (116 or 146) of the pair of JH passageways (116, 146) is configured for attachment to a different target region of the same bone of the subject for the intervention. The jig (200) may comprise more than one (e.g. 2, 3, 4) jig bracelets (212, 242) described herein, each configured for attachment to a different JH bracelet (112, 142) at a different target region of the same bone of the subject for the intervention. More than one jig bracelet (212, 242) allows support of placement elements at different target regions. For instance, where a tumor is to be excised by removal of a portion of bone, the distance and pose of the bone portions flanking the removed bone portion can be maintained by a scaffold supported by the pair of the jig bracelets (212, 242) - JH bracelets (112, 142) flanking the site of the bone removal allowing, the scaffold to span the site of the bone removal.

[0333] According to one aspect, the jig (200) comprises a pair of the jig bracelets (212, 242), wherein each jig bracelet (212, 242) of the pair of jig bracelet (212, 242) is configured for attachment to a different J H bracelet (112, 142) of the pair of the JH bracelets (112, 142).

[0334] According to one aspect, the jig (200) comprises a pair of the jig bracelets (212, 242), wherein each jig bracelet (212, 242) comprises:

[0335] - the jig bracelet body (214, 244) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’) (and having a ring shape);

[0336] - the jig passageway (216, 246) disposed in the (ring shape of the) jig bracelet body (214, 244) between the proximal end and the distal end (thereby giving the jig bracelet body (214, 244) a ring shape);

[0337] - the jig coupling region (218, 248) comprising at least a part of (preferably all of) an interior annular circumferential surface of the jig passageway (216, 246). The jig coupling region (218, 248) further comprises one or more jig anti-displacement elements (220, 220’; 250, 250’) to prevent displacement (e.g. by axial sliding) of the jig bracelet body (214, 244) relative to the JH bracelet body (114, 144) coupled to the jig bracelet body (214, 244). wherein each jig bracelet body (214, 244) has an assembled state (214ASM; 244ASM) and disassembled state (214DASM; 244DASM), wherein:

[0338] - each jig bracelet body (214, 244) comprising a plurality (two or more) of jig bracelet body segments (214a, 214b; 244a, 244b); - the plurality of jig bracelet body segments (214a, 214b or 244a, 244b) of each jig bracelet body (214, 244) in the disassembled state (214DASM; 244DASM), co-operate to form the assembled state (214ASM; 244ASM) for clamping to the JH coupling region (118, 148) of the jig holder (100);

[0339] - wherein each jig bracelet body segment (214a, 214b or 244a, 244b) is a longitudinal segment.

[0340] Each jig bracelet (212, 242) of the pair of jig bracelet (212, 242) is configured for attachment to a different JH bracelet (112, 142) at a different target region of the same bone of the subject for the intervention.

[0341] Each and every jig bracelet body segment (214a, 214b or 244a, 244b) may comprise one or more jig-PE coupling elements (226, 256).

[0342] Each jig bracelet body segment (214a, 214b or 244a, 244b) may or may not be identical in shape and size.

[0343] The different target regions may be disposed on the same bone of the subject for the intervention separated by a separation gap (402).

[0344] The different target regions may be disposed side-by-side on the same bone of the subject for the intervention. In the side-by-side arrangement the separation gap (402) is dimensioned for insertion of a tool such as a blade.

[0345] The different target regions are disposed spaced apart on the same bone of the subject for the intervention. In the spaced apart arrangement, the separation gap (402) is dimensioned to contain a portion of the bone to be removed.

[0346] Further provided is a method for preparing a jig holder (100) as described herein comprising:

[0347] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;

[0348] - identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0349] - for each target region:

[0350] - determining from the three-dimensional medical image: - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;

[0351] - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial (pose) relation to the target region;

[0352] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146);

[0353] - constructing for each target region:

[0354] - a JH bracelet (112, 142) from the three-dimensional structure of a JH bracelet (112, 142), wherein the jig holder (100) comprises the JH bracelet (112, 142) constructed for each target region.

[0355] The three-dimensional structure of a JH bracelet may be provided as a 3D data file. Different 3D data formats are known in the art such as, for instance, STEP, PLY, OBJ, FBX, STL, AMG, IGES.

[0356] The method for preparing is typically performed offline. By offline, it is meant the step

[0357] - receiving a three dimensional medical image; is performed wherein the three dimensional medical image is received from a data storage device (e.g. hard-drive, cloud storage). The method for preparing is not performed on the human or animal body.

[0358] At least the method steps:

[0359] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;

[0360] - identifying one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0361] - for each target region:

[0362] - determining from the three-dimensional medical image:

[0363] - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;

[0364] - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial (pose) relation to the target region;

[0365] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146); are computer-implemented method steps.

[0366] The step of construction may be performed by any construction technique such as, for example, additive manufacturing (3D printing), machining, milling, and the like.

[0367] Further provided is a jig holder (100) obtainable by, directly obtained by, or obtained by a method for preparing a jig holder (100) as described herein.

[0368] Further provided is a method for designing a jig holder (100) as described herein comprising:

[0369] - receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;

[0370] - identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;

[0371] - for each target region:

[0372] - determining from the three-dimensional medical image:

[0373] - a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;

[0374] - a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial (pose) relation to the target region;

[0375] - determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146); wherein the design of the jig holder (100) comprises the three-dimensional structure of the JH bracelet (112, 142) determined for each target region.

[0376] The method for designing is typically performed offline. By offline, it is meant that the step receiving a three dimensional medical image is performed wherein the three dimensional medical image is received from a data storage device (e.g. hard-drive, cloud storage). The three-dimensional structure of a JH bracelet may be provided as a 3D data file. Different 3D data formats are known in the art such as, for instance, STEP, PLY, OBJ, FBX, STL, AMG, IGES.

[0377] The method for designing is a computer-implemented method.

[0378] Further provided is a computing device or system configured for performing the computer implemented method as described herein.

[0379] The system comprises circuitry configured to perform the computer implemented method of the invention. Typically the circuitry comprises a processor and a memory.

[0380] Further provided is a computer program or computer program product having instructions which when executed by a computing device or system cause the computing device or system to perform the computer implemented method as described herein.

[0381] Further provided is a computer readable medium having stored thereon instructions which when executed by a computing device or system cause the computing device or system to perform the computer implemented method as described herein.

[0382] Further provided is a data stream which is representative of a computer program or computer program product having instructions which when executed by a computing device or system cause the computing device or system to perform (each of the steps of) the computer implemented method as described herein.

[0383] The computer implemented method may be performed using a standard computer system such as an Intel Architecture IA-32 based computer system 2, and implemented as programming instructions of one or more software modules stored on non-volatile (e.g., hard disk or solid-state drive) storage associated with the corresponding computer system. However, it will be apparent that at least some of the steps of any of the described processes could alternatively be implemented, either in part or in its entirety, as one or more dedicated hardware components, such as gate configuration data for one or more field programmable gate arrays (FPGAs), or as application-specific integrated circuits (ASICs), for example.

[0384] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as follows in the spirit and scope of the appended claims.

[0385] Example 1

[0386] The herein disclosed aspects and embodiments of the invention are further supported by the following non-limiting example.

[0387] A patient presented with a malignant bone tumor in the left distal femur requiring a surgical intervention that was an osteotomy (surgical bone-cut) to remove the tumor and whole bone distal of the tumor, and implanting of a standard (non-patient specific) replacement femur (distal portion) implant. The standard replacement femur required precise surgical cuts so that when implanted, the resulting hybrid femur had the same length as the original femur, and the articulating surface of the implant coincided with the articulating surface of the original femur - this required accurate drilling of an axial bore.

[0388] From a three-dimensional CT scan of the femur of the subject, a target region was identified, and a cutting site just proximal of the target region was also identified. A distance between the cutting site and the articulating surface of the original femur was such that when a blade guide was attached to the presently-described system and the femur was cut at the cutting site, the resulting hybrid femur would have the same length as the original femur. This distance was determined using a measuring tool in the PACS system of the hospital. The cutting site was at least 3 cm proximal of a proximal end of the tumor to ensure a high chance of sufficient healthy bone devoid of cancer cells. The standard replacement femur size was selected that would the result in the hybrid femur would have the same length as the original femur.

[0389] Further, from the three-dimensional CT scan, the three dimensional shape of the target region of the femur was determined. The shape was used to determine the three dimensional shape of the JH passageway of the JH bracelet for a form-fitting coupling between the JH bracelet and the target region. This shape was determined using software package Materialise Mimics for segmentation of the bone and creation of the 3D model of the bone. A negative of the target region of the bone was created in the jig holder bracelet a Boolean operation function in a CAD environment (Fusion 360).

[0390] Further, from the three-dimensional CT scan, a pose of the JH passageway relative to the JH coupling region of the JH bracelet was determined that would provide a cut, using a blade guide attached to the jig bracelet, perpendicular to the femur at the cutting site. This pose was determined using measurements from the PACS system.

[0391] A JH bracelet body was prepared based on the three dimensional shape of the JH passageway and on the pose of the JH passageway relative to the JH coupling region, using additive manufacturing (3D printing). The JH coupling region had a standard size and shape for coupling with a jig of standard size and shape. Longitudinal cuts were introduced into the JH bracelet body so as to form JH bracelet body segments.

[0392] A mimetic of the femur of the subject (femur memetic) was designed in a 3D modelling environment and prepared by additive manufacturing from the three-dimensional CT scan.

[0393] The JH bracelet body in the disassembled state was applied to the target region of the femur mimetic. The form-fitting shape allowed the JH bracelet to locate uniquely to the target region in only one pose. The jig was coupled to the JH bracelet thereby retaining the JH bracelet body in the assembled state. The JH bracelet and jig were stably coupled to the target region.

[0394] A removeable blade guide was coupled to the jig - more in particular to the jig-PE coupling elements on the jig bracelet body.

[0395] The blade guide slot had a pose such that the surgical bone cut would result in the remainder of the femur mimetic having the correct length, and such that the angle of the cut would be perpendicular to the femur mimetic. After the femur mimetic was cut, a removeable drill guide was coupled to the jig more in particular to the more jig-PE coupling elements on the jig bracelet body. The drill guide slot had an orientation such that the axial bore created by the drill bit resulted in the articulating surface of the implant (prothesis) coinciding with the articulating surface of the original femur mimetic.

[0396] The drill guide was removed and the prosthesis positioning tool was attached to the jig, more in particular to the jig-PE coupling elements on the jig bracelet body. The prosthesis attached to the prosthesis positioning tool placed the prosthesis in a precise pose relative to the mimetic such that the prosthesis articulating surface had an optimal position in all planes of movement (axial, coronal and sagittal). Example 2

[0397] The herein disclosed aspects and embodiments of the invention are further supported by the following non-limiting example.

[0398] Following ethical approval from Ghent University, a proof-of-concept (POC) study was conducted using ten cadaver femurs. CT imaging was performed for each specimen and a virtual preoperative plan was generated in a 3D environment using 3D Slicer. Based on these plans, patient-specific jig holders as presently described herein were fabricated for each specimen via 3D printing, while the jig (reusable, universal) as described herein was manufactured in metal using CNC machining. The placement elements as described herein (saw guiding slot, drill guide, prosthesis positioning guide) were produced either using 3D printing or CNC machining. For the proof of concept, 3D printed surrogate / dummy reconstruction prosthesis were used.

[0399] The system (jig holder, jig and placement elements as presently described herein) was sequentially applied to perform the osteotomy and distal femur prosthesis placement on the 10 specimens. The system’s accuracy was assessed by quantifying the delta between preoperative and postoperative CT scans. Eight reference points were used to ensure a consistent comparison between the planned and achieved positions. Linear and angular deviations were calculated with respect to the axial, coronal, and sagittal planes within a locally defined coordinate system. Statistical analyses were conducted using R software.

[0400] The use of the jig holder demonstrated high precision in cadaveric trials as set out in Table 1. The jig holder achieved median angular deviations of 0.38° (SD 0.63) in the coronal plane and 0.40° (SD 0.38) in the sagittal plane. Median deviations in osteotomy height and rotation were 2.32 mm (SD 2.26) and 1.84° (SD 1.23), respectively. The results are presented as box plots in FIG. 31. These minimal deviations indicate that the guide accurately replicates the preoperative plan and substantially reduces intraoperative variability, suggesting strong potential for clinical translation. The height deviation was found to be independent of the angular parameters - a distinct advantage over freehand techniques where errors often correlate and compound. This precise alignment enhances implant stability and load distribution, safeguards adequate oncological margins, and contributes to improved functional outcomes and long-term prosthesis survival.

[0401] Table 1 : Deviations between planned and achieved positions for the reconstruction prosthesis implanted using the present jig holder in Example 2. SD - standard deviation; IQR - interquartile range.

Claims

1. 54Claims1. A system (1000) for assisting a surgical intervention on a bone of a subject comprising:- a jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:- a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);- a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;- a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) configured for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein:- each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);- the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (114DASM, 144DASM), are configured to co-operate to form the assembled state (114ASM, 144ASM) and the JH passageway (116, 146) for a form-fit coupling to the target region of the bone of the subject for the surgical intervention;- the JH bracelet body (114, 144) in the assembled state (1 14ASM, 144ASM) is a circumferentially closed annular ring; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144).

2. A system (1000) according to claim 1 , wherein each JH bracelet body segment (114a, 114b; 144a, 144b) contains a segment gap (114a’) configured to allow access to the JH passageway (116, 146) in a peripheral to central direction, wherein the segment gap (114a’) has a geometry of missing JH bracelet body segment(s) (114a, 114b; 144a, 144b)55 that constitute the JH bracelet body (114, 144) in the assembled state (1 14ASM, 144ASM), and for each and every JH bracelet body segment (114a, 114b; 144a, 144b), the segment gap (114a’) has a minimum outer circumference (Gcircum) that is at least 50% of the total outer circumference (Tcircum) of the JH bracelet body (114, 144) in the assembled state (1 14ASM, 144ASM).

3. The system (1000) according to any one of the previous claims, further comprising:- a jig (200) configured for dismountable attachment to the jig holder (100), wherein the jig (200) comprises at least one jig bracelet (212, 242), wherein each jig bracelet (212, 242) comprises:- a jig bracelet body (214, 244) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);- a jig passageway (216, 246) disposed in the jig bracelet body (214, 244) between the proximal end and the distal end;- a jig coupling region (218, 248) comprising at least a part of an interior annular circumferential surface of the jig passageway (216, 246) configured for dismountable coupling to and alignment with the JH coupling region (118, 148) of the JH bracelet body (114, 144); wherein each jig bracelet body (214, 244) has an assembled state (214ASM, 244ASM) and a disassembled state (214DASM ,244DASM), wherein:- each jig bracelet body (214, 244) comprising a plurality (two or more) of CJ bracelet body segments (214a, 214b; 244a, 244b);- the plurality of jig bracelet body segments (214a, 214b; 244a, 244b) of each jig bracelet body (214, 244) in the disassembled state (214DASM ,244DASM), is configured to co-operate to form the assembled state (214ASM, 244ASM) for- coupling to the JH coupling region (118, 148) of the JH bracelet body (114, 144); and- retention of the JH bracelet body segments (114a, 114b; 144a, 144b) by the jig bracelet (212, 242) such that JH bracelet body segments (114a, 114b; 144a, 144b) maintain the assembled state (114ASM, 144ASM);56 wherein each jig bracelet body segment (214a, 214b; 244a, 244b) is a longitudinal segment of the jig bracelet body (214, 244).

4. The system (1000) according to claim 3, wherein the jig bracelet (212, 242) is disposed with a placement element (300) that is an element useful during the surgical intervention whose pose with respect to the bone of the subject needs to be known or is readable, wherein the placement element (300) is disposed in known or readable relation with the jig bracelet (212, 242).

5. The system (1000) according to claim 3, wherein the jig bracelet (212, 242) is disposed with a coupling element for a placement element, a jig PE coupling element (226), wherein the placement element (300) is an element useful during the surgical intervention whose pose with respect to the bone of the subject needs to be known or is readable, wherein the placement element (300) is disposed in known or readable relation with the jig bracelet (212, 242).

6. The system (1000) according to claim 4 or 5, wherein the placement element (300) is:- a guide such as a blade guide (310, 310’), a drill guide (330), a slotted guide (340), an implant guide;- a support, such as a rod (350, 350’) or scaffold (352); or- a navigation landmark, such as a body having a camera-readable three-dimensional geometry or a transponder that emits an electromagnetic signal that is detectable by a transponder reader.

7. The system (1000) according to any one of the previous claims, wherein the jig holder (100) comprises a pair of the JH bracelets (112, 142) wherein each JH passageway (116 or 146) of the pair of JH passageways (116, 146) is configured for attachment to a different target region of the same bone of the subject for the intervention.

578. The system (1000) according to claim 7, wherein the jig (200) comprises a pair of the jig bracelets (212, 242), wherein each jig bracelet (212, 242) of the pair of jig bracelet (212, 242) is configured for attachment to a different JH bracelet (112, 142) of the pair of the JH bracelets (112, 142).

9. The system (1000) according to any one of claims 3 to 8, wherein each jig bracelet body segment (214a, 214b; 244a, 244b) comprises one or more fixture elements configured for attaching the respective jig bracelet body segment (214a, 214b or 244a, 244b) to each other using one or more fasteners, thereby retaining jig bracelet body segments (214a, 214b; 244a, 244b) in the assembled state (214ASM, 244ASM) and retaining the JH bracelet body segments (114a, 114b; 144a, 144b) in the assembled state (114ASM, 144ASM).

10. The system (1000) according to claim 9, configured such that the attaching of the respective jig bracelet body segment (214a, 214b or 244a, 244b) is adjustable, such that an adjustment changes a force of clamping applied by the respective jig bracelet body segments (214a, 214b; 244a, 244b) to JH coupling region (118, 148) of the JH bracelet (112, 142).

11. The system (1000) according to claim 10, configured such that the force of clamping applied by the respective jig bracelet body segments (214a, 214b; 244a, 244b) to JH coupling region (118, 148) of the JH bracelet (112, 142) is transmitted to the target region of the bone of the subject.

12. A computer-implemented method for designing a jig holder (100) comprised in a system (1000) for assisting a surgical intervention on a bone of a subject comprising wherein:- the jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:- a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);- a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;- a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (114DASM, 144DASM), wherein:- each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);- the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (1 14DASM, 144DASM), co-operate to form the assembled state (1 14ASM, 144ASM) for a form-fit coupling by the JH passageway (116, 146) to the target region of the bone of the subject for the surgical intervention;- the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) forms a circumferentially closed annular ring; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144);the method comprises:- receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;- identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;- for each target region:- determining from the three-dimensional medical image:- a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region, thereby allowing a form-fitting attachment to the target region of the bone of the subject;- a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial (pose) relation to the target region;- determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146); wherein the design of the jig holder (100) comprises the three-dimensional structure of the JH bracelet (112, 142) determined for each target region.

13. A method for preparing a jig holder (100) comprised in a system (1000) for assisting a surgical intervention on a bone of a subject comprising wherein:- the jig holder (100), JH, comprising at least one JH bracelet (112, 142) wherein each JH bracelet (112, 142) comprises:- a longitudinal JH bracelet body (114, 144) having a proximal end, a distal end, a central direction towards a central longitudinal axis (A-A’), and a peripheral direction away in a perpendicular direction from the central longitudinal axis (A-A’);- a JH passageway (116, 146) disposed in the J H bracelet body (114, 144) between the proximal end and the distal end, and having a shape complementary to a target region of the bone of the subject for the surgical intervention;- a JH coupling region (118, 148) comprising a ring of exterior surface of the JH bracelet body (114, 144) for repeatable dismountable coupling to and alignment with a jig (200); wherein each JH bracelet body (114, 144) has an assembled state (114ASM, 144ASM) and disassembled state (1 14DASM, 144DASM), wherein:- each JH bracelet body (114, 144) comprises a plurality of JH bracelet body segments (144a; 144b);- the plurality of JH bracelet body segments (144a; 144b) of each JH bracelet body (144) in the disassembled state (1 14DASM, 144DASM), co-operate to form the assembled state (1 14ASM, 144ASM) for a form-fit coupling by the JH passageway(116, 146) to the target region of the bone of the subject for the surgical intervention;- the JH bracelet body (114, 144) in the assembled state (114ASM, 144ASM) forms a circumferentially closed annular ring; wherein each JH bracelet body segment (144a; 144b) is a longitudinal segment of the JH bracelet body (114, 144);the method comprises: the method comprises:- receiving a three dimensional medical image of a bone of a subject for a surgical intervention thereon;- identifying from the three dimensional medical image one or more target regions of the bone, wherein a target region is adjacent to a tumor present in the bone;- for each target region:- determining from the three-dimensional medical image:- a shape of a JH passageway (116, 146) of a JH bracelet (112, 142), wherein the shape of a JH passageway (116, 146) is complementary to the shape of the bone in the target region;- a pose of the JH passageway (116, 146) within a JH bracelet body (114, 144) of the JH bracelet (112, 142), wherein the pose of the JH passageway (116, 146) causes the JH coupling region (118, 148) to align in known spatial relation to the target region;- determining a three-dimensional structure of a JH bracelet (112, 142) from the shape and pose of the JH passageway (116, 146);- constructing for each target region:- a JH bracelet (112, 142) from the three-dimensional structure of a JH bracelet (112, 142); wherein the jig holder (100) comprises the JH bracelet (112, 142) constructed for each target region.6114. A jig holder (100) obtained by a method for preparing a jig holder (100) according to claim 13.

Images