Tibial guide for arthroplastic surgery of a tibio-femoral joint and kit for arthroplastic surgery of a tibio-femoral joint

Abstract

A tibial guide (1) for arthroplastic surgery of a tibio-femoral joint comprises a main body (2) provided with a plurality of anchoring portions (5) with a proximal end of a tibia (T) and at least one guide slot (6) crossable by a bone resection instrument along a cutting direction. A first connecting arm (3) of the main body (2) with a first zone (Z1) of a tibial plateau (TP) extends along its own first main direction (B) to a connecting end (3a) with the tibial plateau (TP) and a second connecting arm (4) of the main body (2) with a second zone (Z2) of the tibial plateau (TP) extends along its own second main direction (C) to a connecting end (4a) with the tibial plateau (TP). There are also two fasteners (7, 8) removably graftable within the respective first (Z1) or second zone (Z2) of the tibial plateau (TP) and each provided with a proximal housing portion (7a, 8a) magnetically connected, reversibly, to the connecting end (3a, 4a) of the first (3) or second arm (4).

Description

[0001] "TIBIAL GUIDE FOR ARTHROPLASTIC SURGERY OF A TIBIOFEMORAL JOINT AND KIT FOR ARTHROPLASTIC SURGERY OF A TIBIO-FEMORAL JOINT" DESCRIPTION

[0002] Field of application

[0003] The present invention relates to a tibial guide for arthroplastic surgery of a tibio-femoral joint and a kit for arthroplastic surgery of a tibio-femoral joint.

[0004] In the flexion-extension movement of a non-pathological knee, there is a natural relative rotation between the tibia and femur. In particular, from extension to flexion, the femur rotates externally relative to the tibia rotating around the point of medial contact between tibia and femur (medial pivoting); as a consequence, the point of lateral contact between tibia and femur moves towards the posterior part of the lateral tibial plateau.

[0005] The relative rotation of the tibia - femur during the flexion-extension movement of the knee is an important aspect for the functions of the knee itself and can be altered following total knee arthoplatic (TKA) surgery. This alteration can cause the reduction of internal rotation of the tibia resulting in the normal functions of the joint not being restored.

[0006] Many parameters can influence the internal rotation of the tibia and the external rotation of the femur in the flexion and extension movements, such as implant design, component positioning or the orientation, thickness and angulation of tibial and femoral resections.

[0007] The cuts made on the tibia and femur, in order to make the mating surface with a respective prosthesis, may not be precise and this may affect the ability of the femur to rotate relative to the tibia, also preventing it from having the correct 20° rotation. This causes pain to the patient because the tendons elongate to follow the set rotation or, alternatively, instability of the knee may occur because an intra or extra-rotation can lead to instability in the coupling between the two parts of the joint. Prior art

[0008] To overcome this problem, the known technique makes available tibial guides that allow the cutting plane to be identified precisely, either by using the femur as a reference or by resting directly on the tibial plateau.

[0009] In the first case, the guide is anchored to the femoral insert of the prosthesis (or to a trial insert) in order to determine its position relative to the mechanical axis of the limb having as reference the proximal portion of the joint.

[0010] In the second case, instead, the same Applicant has over time developed a solution that, in the absence of constraint to the femur, allows the surgeon to determine the orientation of the cutting plane using the tibial plateau as a reference; this allows optimizing the determination of the cutting plane when the surgeon decides to use an operating technique of kinematic alignment of the tibia.

[0011] A solution of this type is shown in patent publication EP3846701 , in the name of the same Applicant, which illustrates a tibial guide provided with a main body to which two connecting arms are associated that slide relative to the main body and pivoted to the main body (or rotatable relative to it) at a common rotation axis.

[0012] This allows to obtain a patient-specific alignment, which is able to adapt even to joint morphologies that deviate significantly from the neutral position (aligned with the mechanical axis of the limb).

[0013] Disadvantageously, however, the absence of a reference element already anchored to a patient's limb (e.g. femoral insert) sometimes reduces the stability of the tibial guide during positioning, prior to bone fixation.

[0014] This may lead the surgeon to prolong a stabilization phase which, in the presence of a fixed reference, could be avoided or in any case reduced.

[0015] On the other hand, the very nature of this type of alignment systems aims to provide the surgeon with maximum flexibility of movement and inclination both relative to the medial-lateral axis and relative to the anterior-posterior axis, reducing the possibilities of anchoring.

[0016] The Applicant has therefore perceived that it would be desirable to make a tibial guide for arthroplastic surgery of a joint that would be able to guarantee stability of positioning and fixation without compromising the operational and functional flexibility of the instrument.

[0017] The object of the present invention is therefore to make available a tibial guide and a kit for arthroplastic surgery of a joint that are able to overcome the drawbacks of the aforementioned prior art.

[0018] In particular, it is an object of the present invention to make available a tibial guide and a kit for arthroplastic surgery of a joint that is both precise and versatile.

[0019] Said objects are achieved by a tibial guide and a kit for arthroplastic surgery of a joint having the features of one or more of the following claims.

[0020] In this regard, it should be noted that, in this text, the terms "anterior", "posterior", "distal", "proximal", "medial" and "lateral" will refer to the body references commonly used in anatomy.

[0021] Summary of the invention

[0022] The objects illustrated above are achieved by a tibial guide for arthroplastic surgery of a tibio-femoral joint comprising a main body, a first connecting arm and a second connecting arm.

[0023] Preferably, the main body is provided with a plurality of anchoring portions with a proximal end of the tibia and at least one guide slot crossable by a bone resection instrument along a cutting direction.

[0024] Preferably, the first connecting arm is configured to connect the main body with a first zone of a tibial plateau.

[0025] Preferably, the first connecting arm extends along its own first main direction to a connecting end with the tibial plateau.

[0026] Preferably, the second connecting arm is configured to connect the main body with a second zone of said tibial plateau.

[0027] Preferably, the second connecting arm extends along its own second main direction to a connecting end with the tibial plateau.

[0028] Preferably, the tibial guide comprises two fasteners removably graftable within the respective first or second zone of the tibial plateau.

[0029] Preferably, moreover, the fasteners are each provided with a proximal housing portion magnetically connected, reversibly, to the connecting end of the first or second arm.

[0030] Advantageously, in this way it is possible to anchor the fasteners prior to the positioning of the guide and in appropriately selected fixation zones (for example as a function of the level of wear of the cartilage), positioning and adjusting only at a later time the guide, i.e. the main body that will be, at a later time, fixed to the tibia to proceed with the resection.

[0031] Preferably, the fasteners have a distal portion graftable within the respective first or second zone of the tibial plateau.

[0032] Preferably, the proximal portion of the fasteners has a concave shape with a concavity facing away from the distal portion.

[0033] Preferably, the connecting ends of the first and second arms comprise a convex end portion shaped to fit, with the possibility of rotation, within said concavity.

[0034] Preferably, each proximal housing portion of a fastener defines, with the connecting end of the respective first and second arms, a magnetic ball joint.

[0035] Preferably, each connecting end comprises a magnet encapsulated in a casing.

[0036] More preferably, the magnet is encapsulated in the convex end portion.

[0037] Preferably, each connecting end comprises a cup-shaped portion defining a housing volume for the magnet and provided with an open proximal end occluded by a closing septum.

[0038] Preferably, the fasteners comprise an elongated anchoring portion shaped to penetrate said first or second zone of the tibial plateau. Brief description of the drawings

[0039] The present invention will become clearer from the exemplary, therefore non-limiting, description of preferred, therefore non-exclusive, embodiments of a tibial guide and of a kit for arthroplastic surgery of a tibio-femoral joint as illustrated in the attached drawing tables, in which:

[0040] - figures 1 -3 show a perspective, a top and a lateral view of a tibial guide for arthroplastic surgery of a tibio-femoral joint according to the present invention;

[0041] - figure 4 shows a detail of the tibial guide of figures 1 -3;

[0042] - figures 5 and 5a show a portion of the detail of figure 4 in top view and in section along the section line Va-Va;

[0043] - figures 6a-6d show in sequence a surgical procedure exploiting the tibial guide of figures 1 -3.

[0044] Detailed description

[0045] With reference to the attached figures, a tibial guide for arthroplastic surgery of a tibio-femoral joint has been indicated with 1 .

[0046] The tibial guide 1 subject-matter of the present invention is used intra- operatively to verify and determine the correct orientation of the tibial cutting surface, on which the definitive insert must be grafted.

[0047] To position the prosthetic insert, it is in fact necessary to section the proximal portion of the tibia in order to remove the tibial plateau, part of the knee joint on which they articulate respectively with the medial and lateral femoral condyles; both the tibial plateau and the femoral condyles are in fact replaced by the prosthetic implant to restore the correct functionality of the joint.

[0048] The tibial guide 1 preferably comprises a main body 2 and a connecting group 10 connected to the main body 2 and configured to connect the main body 2 to the tibial plateau "TP".

[0049] The main body 2 comprises a plurality of anchoring portions 5 with the proximal end of the tibia T and a guide slot 6 crossable by a bone resection instrument.

[0050] Note that the guide slot 6 of the tibial guide 4 defines a cutting plane "P" transverse to a mechanical axis "V" of the limb.

[0051] In the preferred embodiment, the main body 2 has a partially curved shape in order to partially take up the curvature of the tibia "T".

[0052] The curved portion 2a defines a curvature around the mechanical axis "V" of the limb, i.e. with a concavity facing, in use, towards the tibia "T".

[0053] The guide slot 6 is defined by a through notch presenting a main extension direction along a medial-lateral direction "A".

[0054] Preferably, the guide slot 6 also has a curved shape shaped like the curved portion 2a of the main body 2.

[0055] The fixation portions 5 are instead defined by one or more through holes shaped to accommodate anchoring elements (e.g. screws) that the surgeon, having completed the positioning and orientation of the main body 2, will insert into the tibia "T".

[0056] The tibial guide 1 , and in particular the connecting group 10, further comprises a first 3 and a second 4 connecting arm, both configured to connect the main body 2 to the tibial plateau "TP".

[0057] In particular, the first arm 3 is configured to connect the main body 2 with a first zone "Z1" of the tibial plateau "TP".

[0058] The second arm 4 is instead preferably configured to connect the main body 2 with a second zone "Z1" of the tibial plateau "TP".

[0059] Preferably, the first 3 and the second arm 4 extend along respective main directions to a connecting end 3a, 4a with the tibial plateau "TP".

[0060] The first arm 3 extends along a first main direction "B".

[0061] The second arm 4 extends along a second main direction "C".

[0062] Preferably, both the first 3 and the second arm 4 are configured to rotate (i.e. to be rotated) relative to the main body 2 around at least one common rotation axis "D" to allow a correct positioning of the main body 2.

[0063] Preferably, the rotation axis "D" is substantially orthogonal to the first "B" and the second main direction "C", more preferably substantially aligned to the mechanical axis "V"; in other words, the rotation axis "D" is preferably aligned to a proximal-distal direction.

[0064] Note that the rotation of the two arms 3, 4 relative to the main body 2 is preferably independent; in other words, the first arm 3 can rotate relative to the main body 2 independently of the second arm 4, and vice versa.

[0065] In this regard, the connecting group 10 preferably comprises a pin element 9 extending along the rotation axis "D".

[0066] Preferably, therefore, the first 3 and the second connecting arm 4 are rotatably connected to the main body 2 by means of the pin element 9.

[0067] Each arm 3, 4 is preferably rotatably connected to the pin element 9 independently of the other arm.

[0068] Preferably, the pin element 9 extends from the main body 2 in a proximal- distal direction, being preferably located in a position proximal to the guide slot 6.

[0069] Preferably, moreover, at least the first arm 3 is slidably associated with the main body 2 to be translated from it relative to a first adjustment direction. The first adjustment direction is preferably aligned with the first main direction "B".

[0070] In other words, preferably the position of the rotation axis "D" along the first arm 3 can vary between a position close to the connecting end 3a and a position far from the connecting end.

[0071] Advantageously, the set of at least one linear degree of freedom (sliding of the first arm 3) together with two rotational degrees of freedom (rotation of both arms 3, 4) allows to vary the position and orientation of the main body 2, and therefore of the cutting slot 6, depending on both the positioning of the first "Z1" or second zone "Z2" of the tibial plateau "TP" and the desired orientation for the cutting plane "P".

[0072] In the preferred embodiment, the second arm 4 is also slidably associated with the main body 2 to be translated from it along a second adjustment direction. Preferably, the second adjustment direction is aligned with the second main direction "C".

[0073] It should be noted that, preferably, at least the first connecting arm 3 has a terminal end 3b opposite the connecting end 3a.

[0074] Preferably, the first connecting arm 3 is shaped so that the rotation axis "D" is interposed between the connecting end 3a and the terminal end 3b.

[0075] In other words, the pin element 9 is interposed between the connecting end 3a and the terminal end 3b.

[0076] Preferably, the first connecting arm 3 comprises a longitudinal notch 3c extending along the first adjustment direction "B" between the connecting end 3a and the terminal end 3b.

[0077] The pin element 9 is inserted by crossing the longitudinal notch 3c, with the possibility of sliding inside it along the first adjustment direction "B".

[0078] Preferably, the terminal end 3b is shaped to allow the surgeon to move the first arm 3 once it is coupled to a respective fastener 7.

[0079] In the preferred embodiment, the terminal end 3b comprises a grippable portion 11 a, preferably a tab, adapted to facilitate adjustment operations by the surgeon.

[0080] Preferably, it should be noted that the second connecting arm 4 also has a terminal end 4b opposite the connecting end 3a.

[0081] More preferably, the second connecting arm 4 is shaped so that the rotation axis "D" is interposed between the connecting end 4a and the terminal end 4b.

[0082] In other words, the pin element 9 is interposed between the connecting end 4a and the terminal end 4b.

[0083] Preferably, also the second connecting arm 3 comprises a longitudinal notch 4c extending along the second adjustment direction "C" between the connecting end 4a and the terminal end 4b.

[0084] The pin element 9 is therefore inserted by crossing the longitudinal notch 4c, with the possibility of sliding inside it along the second adjustment direction "C".

[0085] In the preferred embodiment, the terminal end 4b comprises a grippable portion 11 b, preferably a tab, adapted to facilitate adjustment operations by the surgeon.

[0086] Preferably, both the first 3 and the second arm 4 have, at the connecting end 3a, 4a, a folded portion, or elbow, to allow the arm itself to stay away from the tibial plateau "TP" while extending mostly parallel to it.

[0087] In other words, starting from the connecting end 3a, 4a, the arms 3, 4 extend with an inclined section oriented away, in use, from the tibial plateau and connected with a longitudinal section oriented along the respective first "B" or second main direction "C".

[0088] Preferably, the inclined section forms with the longitudinal section an angle between 90° and 160°.

[0089] In order to block the position of the main body 2 relative to the first 3 and / or the second arm 4, the pin element 9 comprises a tightening group 9a switchable from a release configuration and a tightening configuration.

[0090] In the release configuration, the tightening group 9a allows relative movement between the arms 3, 4 and the main body 2. In the tightening configuration, the tightening group 9a is configured to make the connecting arms 3, 4 and the main body 2 integral.

[0091] In the preferred embodiment, the tightening group 9a comprises a threaded coupling.

[0092] Advantageously, this allows to modulate the freedom of reciprocal movement between elements as a function of the degree of tightness.

[0093] Preferably, the pin element 9 comprises a rest shoulder for the first 3 and / or the second arm 4 and a threaded head on which a tightening nut 9b is screwed which, in the tightening configuration, presses the arms 3, 4 against the rest shoulder.

[0094] The first 3 and the second arm 4 are therefore superimposed, with the second arm 4 resting on the shoulder and the tightening nut 9b being pressed on the first arm 3.

[0095] Furthermore, preferably, the connecting group 10 is reversibly connected to the main body 2, in order to free up space for the surgeon when resecting the tibial plateau.

[0096] The connecting group 10 is connected to the main body 2 via one or more anchoring elements (not illustrated).

[0097] In the preferred embodiment, the connecting group 10 comprises a quick release member 10a configured to release the connecting group 10 from the main body 2.

[0098] Preferably, the quick-release member 10a is associated with the anchoring elements to move them from an engagement position to a disengagement position with the main body.

[0099] In the preferred embodiment, the quick-release member 10a and the anchoring elements are associated with the pin 9.

[0100] In the preferred embodiment, the quick-release member 10a comprises an actuation button 10c; more preferably, said button protrudes above the connecting group 10, even more preferably above the pin 9.

[0101] According to one aspect of the invention, the tibial guide 1 comprises at least two fasteners 7, 8 removably graftable within the respective first "Z1 " or second zone "Z2" of the tibial plateau "TP".

[0102] A first fastener 7 is associated with the first connecting arm 3.

[0103] A second fastener 8 is associated with the second connecting arm 4.

[0104] Preferably, said fasteners 7, 8 are each provided with a proximal housing portion 7a, 8a and a distal portion 7b, 8b.

[0105] Preferably, the distal portion 7a, 7b of each fastener 7, 8 is graftable within the respective first "Z1 " or second zone "Z2" of the tibial plateau.

[0106] Preferably, the proximal portion 7a, 8a is magnetically connected, reversibly, to the connecting end 3a, 4a of the first 3 or the second arm 4, respectively.

[0107] The proximal portion 7a of the first fastener 7 is magnetically connected, reversibly, to the connecting end 3a of the first connecting arm 3.

[0108] The proximal portion 8a of the second fastener 8 is magnetically connected, reversibly, to the connecting end 4a of the first connecting arm 4. Advantageously, in this way the surgeon can proceed with anchoring the fasteners 7, 8 on the tibial plateau "TP", by appropriately selecting the first zone "Z1 " and the second zone "Z2" as a function of the bone anatomy or the level of wear of the cartilage.

[0109] Once the fasteners 7, 8 are positioned and anchored, the coupling with the connecting arms 3, 4 of the guide 1 is simple and immediate thanks to the magnetic connection, leaving the surgeon the sole task of determining the position and inclination of the cutting plane "P".

[0110] It should be noted that, preferably, the connecting end 3a, 4a of each arm 3, 4 and the corresponding proximal portion 7a, 8a of the respective fastener 7, 8 are shaped so as to define a rotational coupling, more preferably a spherical joint.

[0111] This advantageously leaves the arms 3, 4 only the freedom to rotate relative to the corresponding proximal portion 7a, 8a of the respective fastener 7, 8, facilitating the surgeon in determining the correct inclination of the cutting plane "P".

[0112] Preferably, the proximal portion 7a, 8a of the fasteners 7, 8 has a concave shape with a concavity facing away from the distal portion 7b, 8b.

[0113] In this regard, the connecting ends 3a, 4a of the first 3 and the second arm 4 comprise a convex end portion shaped to fit, with the possibility of rotation, within said concavity.

[0114] Advantageously, in this way the variation of inclination of the arms (and therefore of the main body) relative to the tibial plateau is simple and smooth.

[0115] Preferably, the proximal housing portion 7a, 8a of a fastener 7, 8 defines, with the connecting end 3a, 4a of the respective first 3 or second arm 4, a magnetic ball joint.

[0116] In other words, the proximal housing portion 7a of the first fastener 7 defines, with the connecting end 3a of the first arm 3, a magnetic ball joint. The proximal housing portion 8a of the second fastener 8 defines, with the connecting end 4a of the second arm 4, a magnetic ball joint. The expression "ball joint" means a joint that allows a component to rotate around all three axes without translations, preferably using a nested three- rotation cardan system.

[0117] Preferably, the joint provides a magnetic connection between the arm and the respective fastener.

[0118] Preferably, each connecting end 3a, 4a of each arm 3, 4 comprises a magnet 17 encapsulated in a casing 12.

[0119] The magnet 17 is magnetically coupled with the proximal portion 7a, 8a of the respective fastener 7, 8, made of ferromagnetic material.

[0120] Preferably, the magnet 17 is encapsulated in the convex end portion.

[0121] In this regard, preferably each connecting end 3a, 4a comprises a cupshaped portion 12a defining a housing volume for the magnet 17 and provided with an open proximal end, occluded with a closing septum 12b.

[0122] The closing septum 12b is constrained to the edge of the proximal end of the cup-shaped portion 12a by means of a form-fitting, an interlocking or by means of welding.

[0123] The cup-shaped portion 12a and the closing septum 12b preferably define the casing 12.

[0124] Preferably, moreover, the fasteners 7, 8 comprise an elongated anchoring portion 13 shaped to penetrate said first "Z1" or second zone "Z2" of the tibial plateau.

[0125] The anchoring portion 13 defines the distal end 7b, 8b of the fasteners 7, 8.

[0126] In some embodiments, the anchoring portion 13 has a tapered and threaded shape, in others simply a pointed shape adapted to penetrate the cartilage and bone at the tibial plateau "TP".

[0127] With reference to the illustrated embodiment, the fasteners 7, 8 are defined by screws 14 provided with a concave head 14a defining the proximal housing portion 7a, 8a for the connecting end 3a, 4a of the respective first 3 or second arm 4.

[0128] Preferably, the concave head 14a of the screw 14 has an axial hole with a polygonal head to facilitate the tightening of said screw 14 itself in the tibial plateau "TP".

[0129] Alternatively, in an embodiment not illustrated, the fasteners 7, 8 could be defined by tacks, also provided with a concave head but which are insertable into the tibial plateau only through pressure.

[0130] Preferably, moreover, the main body 2 comprises a spacer device 15 protruding from a rear face 2b thereof.

[0131] This spacer device 15 therefore protrudes from the face of the main body 2 facing the tibia T.

[0132] The spacer device 15 is therefore configured to vary an inclination of the guide slot 12 relative to a reference plane of the tibial plateau "TP".

[0133] Preferably, the "reference plane" is defined by the plane passing through contact points between the tibial guide 1 and the tibia "T".

[0134] A first contact point P1 is preferably defined between the connecting end 3a of the first arm 3 and the respective first fastener 7.

[0135] A second contact point P2 is preferably defined between the connecting end 4a of the second arm 4 and the respective second fastener 8.

[0136] A third contact point P3 is preferably defined by a free end 15a of the spacer device 15 adapted to contact the tibia in a third contact zone "Z3".

[0137] Thanks to the possibility of the arms 3, 4 to rotate relative to the fasteners 7, 8 and to the adjustability of the spacer device, the determination of the correct cutting angle for the resection of the tibial plateau is simple and intuitive for the surgeon.

[0138] Preferably, the spacer device 15 comprises an adjusting setscrew 16 rotatably connected to the main body 2.

[0139] In this regard, therefore, the adjusting setscrew is placed by crossing the main body 2, with a predetermined inclination, and extends between the free end 15a, which in use contacts the tibia, and an activation end provided with a housing seat of a rotation tool (for example, an Allen screw, screwdriver or screw gun)

[0140] Preferably, moreover, the presence of a scraping tool 20 for removing cartilage tissue is also provided, which together with the tibial guide defines a kit for arthroplastic surgery, also subject-matter of the invention. The surgical equipment described so far allows an innovative surgical procedure to be performed, mainly characterised by the possibility of defining the rest and fixation points of the tibial guide in advance.

[0141] This procedure will therefore be described below, where possible by indicating characteristics already introduced previously with the same reference numbers.

[0142] According to this procedure, schematically illustrated in figures 6a-6d, the first step is to determine the placement of the first "Z1 " and the second zone "Z2" of the tibial plateau "TP".

[0143] Preferably, the cartilage still present in these zones is removed with the aid of the scraping tool 20.

[0144] At this point, the fasteners 7, 8 are anchored to the tibial plateau "TP", at the first zone "Z1 " and the second zone "Z2", respectively.

[0145] In the case of screws, each anchoring portion 13 of the respective fastener 7, 8 is screwed into the tibial plateau "TP".

[0146] It is then proceed with the connection, preferably magnetic, between the connecting ends 3a, 4a of the arms 3, 4 and the proximal portions 7a, 8a of the fasteners 7, 8.

[0147] Using the tightening group 9a, the two arms 3, 4 are released in order to place the main body 2 in the correct anterior-posterior position, preferably by resting the spacer device 15 on the tibia "T".

[0148] At this point the spacer device 15, in particular the setscrew 16, is adjusted to determine the correct angular position of the guide slot 6.

[0149] The main body 2 is therefore fixed to the tibia "T" by means of the anchoring portions to crystallize the correct orientation of the cutting plane. In the preferred embodiments, finally, the connecting group 10 is released from the main body 2, preferably by means of the quick-release member 10a.

[0150] At this point, the surgeon can proceed with the resection of the tibial plateau "TP" with the aid of special resection instruments.

[0151] The invention, therefore, achieves the intended purposes and achieves important advantages.

[0152] In fact, the provision of a tibial guide that allows a quick connection between the connecting arms and pre-fixed points of the tibial plateau greatly facilitates the operations by the surgeon, who can thus only dedicate him- / herself to evaluating the correct inclination of the cutting plane.

[0153] Moreover, the use of a magnetic connection system makes the adjustment procedure quick and reliable, to the benefit of the success of the surgical procedure.

Claims

CLAIMS1. Tibial guide (1 ) for arthroplastic surgery of a tibio-femoral joint comprising:- a main body (2) provided with: a plurality of anchoring portions (5) anchorable with a proximal end of a tibia (T); and at least one guide slot (6) crossable by a bone resection instrument along a cutting direction;- a first connecting arm (3) configured to connect the main body (2) with a first zone of a tibial plateau (TP) and extending, along its own first main direction (B), to a connecting end (3a) configured to connect with the tibial plateau (TP);- a second connecting arm (4) configured to connect the main body (2) with a second zone of said tibial plateau (TP) and extending, along its own second main direction (C), to a connecting end (4a) configured to connect with the tibial plateau (TP); characterised in that it comprises two fasteners (7, 8) removably graftable within a respective first (Z1 ) or second zone (Z2) of the tibial plateau and each one provided with a proximal housing portion (7a, 8a) magnetically connected, reversibly, to the connecting end (3a, 4a) of the first (3) or second arm (4).

2. Tibial guide according to claim 1 , wherein said fasteners (7, 8) have a distal portion (7b, 8b) graftable within the respective first (Z1 ) or second zone (Z2) of the tibial plateau (TP) and wherein the proximal portion (7a, 8a) of the fasteners (8) have a concave shape with the concavity facing away from the distal portion (7b, 8b); said connecting ends (3a, 4a) of the first (3) and second connecting arm (4) comprising a convex end portion shaped to fit, with the possibility of rotation, within said concavity.

3. Tibial guide according to claim 2, wherein each proximal housing portion(7a, 8a) of a fastener (7, 8) defines, with the connecting end (3a, 4a) of the respective first (3) and second connecting arm (4), a magnetic ball joint.

4. Tibial guide according to any one of the preceding claims, wherein each connecting end (3a, 4a) of the connecting arms (3, 4) comprises a magnet (17) encapsulated in a casing (12).

5. Tibial guide according to claim 2 and 4, wherein said magnet (17) is encapsulated in said convex end portion.

6. Tibial guide according to claim 4 or 5, wherein each connecting end (3a, 4a) of the connecting arms (3, 4) comprises a cup-shaped portion (12a) defining a housing volume for the magnet (17) and provided with an open proximal end occluded by a closing septum (12b).

7. Tibial guide according to any one of the preceding claims, wherein said fasteners (7, 8) comprise an elongated anchoring portion (13) shaped to penetrate said first (Z1) or second zone (Z2) of the tibial plateau (TP).

8. Tibial guide according to claim 7, wherein said fasteners (7, 8) are defined by screws (14) provided with a concave head (14a) defining a proximal housing portion (7a, 8a) for the connecting end (3a, 4a) of the respective first (3) or second arm (4).

9. Tibial guide according to claim 7, wherein said concave head (14a) of the screw (14) has a polygonal-head axial hole to facilitate the tightening of said screw (14) in the tibial plateau (TP).

10. Tibial guide according to any one of the preceding claims, wherein the first arm (3) is slidably associated with the main body (2) to be translated from it relative to a first adjustment direction.11 . Tibial guide according to any one of the preceding claims, wherein said second arm (4) is slidably associated with the main body (2) to be translated from it relative to a second adjustment direction.

12. Tibial guide according to any one of the preceding claims, wherein said first (3) and second connecting arms (4) are configured to rotate relative to the main body (2) about at least one rotation axis (D) to allow a correct positioning of the main body (2) for each first (Z1) or second zone (Z2) of the tibial plateau (TP).

13. Tibial guide according to any one of the preceding claims, wherein the main body (2) comprises a spacer device (15) protruding from a rear face (2b) thereof and configured to vary an inclination of the guide slot (6) relative to a reference plane of the tibial plateau (TP).

14. Tibial guide according to claim 13, wherein said reference plane is defined by the plane passing through:- a first contact point (P1 ) defined between the connecting end (3a) of the first arm (3) and the proximal portion (7a) of the first fastener (7);- a second contact point (P2) defined between the connecting end (4a) of the second arm (4) and the proximal portion (8a) of the second fastener (8);- a third contact point (P3) defined by a free end (15a) of the spacer device (15) adapted to contact the tibia in a third contact zone (Z3).

15. Tibial guide according to claim 13 or 14, wherein the spacer device (15) comprises an adjusting setscrew (16) rotatably connected to the main body (2).

16. Kit for arthroplastic surgery of a tibio-femoral joint, comprising:- a tibial guide according to any one of the preceding claims;- a scraping tool for removing cartilaginous tissue.

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