Equipment for tibio-femoral arthroplasty surgery

Abstract

An equipment for tibio-femoral arthroplasty surgery comprises a femoral trial component (2), a support body (3) connectable to the femoral trial component (2) and a tibial guide (4) for the tibial cut associated with said support body (3). The femoral trial component (2) is shaped like a shell and is provided with an anterior patellar portion (5) from which a medial condylar portion (6) and a lateral condylar portion (7) branch off, arranged side by side. Each condylar portion (6, 7) comprises a distal part (6b, 7b) and a posterior part (6a, 7a), spaced from the anterior patellar portion (5) by the distal portion (6b, 7b). The tibial guide (4) is provided with a plurality of fastening points (11) with a proximal end of the tibia (T) and a guide slot (12) crossable by a bone resection instrument. In at least one coupling condition between the support body (3) and the femoral trial component (2), the support body (3) is coupled to the anterior patellar portion (5) of the femoral trial implant (2) and protrudes anterior thereto along an antero- posterior direction (A).

Description

[0001] "EQUIPMENT FOR TIBIO-FEMORAL ARTHROPLASTY SURGERY" DESCRIPTION

[0002] Field of application

[0003] The present invention relates to an equipment for tibio-femoral arthroplasty surgery.

[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 coupling 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.

[0008] Prior art The possibility of assessing intra-operatively, therefore before the positioning of the definitive prosthesis, the internal rotation of the tibia with respect to the femur in the flexion-extension movement resulting from the surgical procedure just performed, helps the surgeon to estimate any limitations of knee function and to avoid the aforesaid inconveniences for the patient; being able to carry out this assessment, before attaching the prosthetic components to the bone, potentially allows to be able to correct the resections and positioning just performed, to optimize the performance of the implant.

[0009] To date, to meet these needs, trial components are made available to the surgeon which fully replicate the structure of the prosthetic implant and, at the same time, are equipped with anchors and references that allow the surgeon to assess how to proceed with the resections and the possibility of making corrections.

[0010] With regard to the femoral trial components, applied to the distal end of the already dissected femur, the surgeon usually has a set of trial components of various sizes among which the one most suitable for the patient is selected and applied so that the condylar portions of the insert rest, in a condition of extension of the joint, on the native tibial plateau, that is, on the proximal end of the patient's tibia.

[0011] Such inserts, despite being useful for the purpose, have some drawbacks. Firstly, the currently known trial components have geometry of the anterior, distal and posterior portions completely similar to that of the definitive prosthetic implant, therefore with an anterior patellar portion having significant proximal-distal extension and reduced thickness, capable of supporting limited loads.

[0012] It is no coincidence that both the trial component and the prosthetic implant have a large anterior portion that separates into the two condylar portions (medial and lateral) only at the distal plane. This is clearly not a problem as far as the prosthetic implant is concerned, the femoral portion of which is intended to couple with a corresponding suitably shaped tibial portion.

[0013] The case is different for the trial component, whose function is precisely to provide the surgeon with indications about the coupling of the femoral portion with the tibia and about the tibial resections to be performed.

[0014] In other words, the femoral trial component is to be tested on the tibia in an operative step prior to resections, in which the tibial plateau therefore has the complete structure of the tibial spines, bone protrusions that extend centrally along the disto-proximal direction and therefore risk interfering with both the condylar portions and the anterior patellar portion of the insert.

[0015] To overcome this problem, to date surgeons tend to eliminate the problem upstream, by proceeding to a bone resection of the tibial spines before applying the trial component, a procedure which, however, lengthens the operating step and entails an additional difficulty for the medical team.

[0016] Another problem is related to the canonical execution of the tibial cut, which by exploiting the attachment holes of the femoral trial component at the distal end of the bone only allows the tibial cut to be made in a flexed condition of the tibio-femoral joint.

[0017] Some solutions of the prior art just described are illustrated in patent applications US20210259708 and US20210267607, from which it is clear that the tibial cut in flexion is in fact a standard in the current surgical procedures.

[0018] This, however, is disadvantageous mainly due to the intrinsic nature of the joint, which for obvious reasons in daily activity is only marginally stressed in the flexed condition, hardly representative of the possible problems that the prosthetized patient could face.

[0019] But not only that, during the tibio-femoral arthroplasty procedure, the correct determination of the tibial slope, i.e. the inclination of the resection plane of the tibial plateau with respect to the distal plane, is of decisive importance for the outcome of the operation.

[0020] To date, the procedure involves attaching the femoral trial component and, on the basis of this device, positioning and subsequently attaching the cutting guide to the tibia.

[0021] As is known, however, for the cut to be performed correctly, it is necessary that the resection plane has a predetermined inclination with respect to the mechanical axis of the limb, where by mechanical axis it is intended to define an imaginary straight line drawn between the centre of the epiphysis of the femur and the centre of the ankle.

[0022] For this reason, once the femoral trial component is fastened and the cutting guide is anchored to this element, the surgeon usually makes an adjustment of the inclination by acting directly on the tibia and tilting it appropriately until its inclination corresponds to that desired, usually using his own experience together with reference elements such as sickles or other components capable of simulating the position of the resection plane.

[0023] This obviously makes it difficult, if not impossible, to fine-tune the tibial slope, whose accuracy is in any case closely correlated to the skill or readiness of the medical team and, consequently, subject to strong variability.

[0024] Aim of the present invention is therefore to make available one or more devices capable of overcoming one or more of the aforesaid drawbacks.

[0025] In particular, it is an aim of the present invention to make available an equipment for tibio-femoral arthroplasty surgery capable of optimizing the operating procedure and, in particular, the tibial cutting step.

[0026] A further aim of the invention is to make available a femoral trial component whose positioning does not require the resection of the tibial spines and at the same time simplifies the size identification procedure. Yet, it is also an aim of the present invention to make available a tibial cutting guide and associated equipment that allow a fine adjustment of the tibial slope.

[0027] These and other objects are achieved by a femoral trial component, a tibial guide and an equipment for tibio-femoral arthroplasty surgery having the features of one or more of the following claims.

[0028] 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.

[0029] The "antero-posterior" direction will therefore be understood as an axis that extends between the anterior and the posterior part of the device in its condition of use, with the joint in extension.

[0030] The "proximal-distal" direction, on the other hand, will be understood as an axis that extends between a proximal and a distal part of the device in its condition of use, with the joint in extension.

[0031] The "medial-lateral" direction will be understood as an axis that extends between a medial and a lateral part of the device in its condition of use, with the joint in extension.

[0032] The expression "mechanical axis" of the lower limb means a line that, lowered from the centre of the femoral head in the extended condition of the joint, passes through the centre of the knee and the centre of the tibio- peroneal mortise.

[0033] Summary of the invention

[0034] In particular, the present invention relates to an equipment for tibio-femoral arthroplasty surgery.

[0035] Such equipment preferably comprises a femoral trial component, a support body and a tibial guide.

[0036] Preferably, the femoral trial component is shaped like a shell and provided with an anterior patellar portion from which a medial condylar portion and a lateral condylar portion branch off, arranged side by side. Preferably, each condylar portion comprises a distal part and a posterior part, spaced from the anterior patellar portion by the distal portion.

[0037] Preferably, the distal portion of each condylar portion comprises an attachment zone for a distal end of the femur.

[0038] Preferably, the support body is connectable to the femoral trial component. Preferably, the tibial guide for the tibial cut is connectable to said support body.

[0039] Preferably, the tibial guide is provided with a plurality of fastening points configured to allow the attachment of the tibial guide with a proximal end of the tibia.

[0040] Preferably, furthermore, the tibial guide comprises a guide slot crossable by a bone resection instrument.

[0041] Preferably, in at least a coupling condition between the support body and the femoral trial component, the support body is coupled to the anterior patellar portion of the femoral trial implant and protrudes anteriorly thereto along an antero-posterior direction.

[0042] More preferably, in the coupling condition between the support body and the femoral trial component, the support body is fastened at a distal zone of the anterior patellar portion.

[0043] Preferably, in the coupling condition between the support body and the femoral trial component, the support body extends along a direction substantially orthogonal to the anterior patellar portion.

[0044] Preferably, the femoral trial component comprises at least two openings for coupling with said support body extending in an antero-posterior direction from said anterior patellar portion.

[0045] Preferably, each condylar portion of the femoral trial component has a concave proximal surface and a convex distal surface; said coupling openings extending along said antero-posterior direction between the proximal surface and the distal surface of the distal part of each condylar portion.

[0046] Preferably, the support body comprises a plurality of coupling pins, each insertable into a respective coupling opening.

[0047] Preferably, the support body extends along said antero-posterior direction between a joining terminal and a free terminal.

[0048] Preferably, the joining terminal comprises a fork-shaped element provided with two arms each provided with one of said pins.

[0049] Preferably, the fork-shaped element of the joining terminal of said support body has a coupling face that is counter-shaped to the distal zone of the anterior patellar portion of the femoral trial component.

[0050] Preferably, in the coupling condition between the support body and the femoral trial component, the coupling face is placed against said distal zone of the anterior patellar portion of the femoral trial component.

[0051] Preferably, the guide slot of the tibial guide defines a cutting plane located in a position distal to the femoral trial component and having an inclination between 70° and 110° with respect to a posterior plane in which the posterior part of the condylar portions lies.

[0052] Preferably, the medial and lateral condylar portions extend arranged side by side from the anterior patellar portion in the posterior direction, maintaining a distance adapted to house, at least in part, a tibial spine.

[0053] Object of the present invention is also a femoral trial component, preferably but not necessarily usable within the equipment described so far.

[0054] Preferably, the anterior patellar portion of said femoral trial component comprises a medial half-part and a lateral half-part moving closer to and away from each other along the medial-lateral direction to vary a medial- lateral size of said femoral trial component.

[0055] Further preferably, each condylar portion is movable relative to the anterior patellar portion closer to or away from an antero-posterior direction to vary an antero-posterior size of said femoral trial component.

[0056] Object of the present invention is also a tibial guide for the tibial cut, preferably but not necessarily usable within the equipment described so far. Preferably, said tibial guide comprises a fastening body provided with said plurality of fastening points and a guide body provided with said guide slot. Preferably, the guide body is movable relative to the fastening body to vary an inclination of said cutting direction with respect to the fastening body.

[0057] Preferably, the guide body is slidably associated with the fastening body and shaped so as to move along a curvilinear direction.

[0058] Brief description of the drawings

[0059] These and other advantages of the present invention will become clearer from the exemplary, therefore non-limiting, description of preferred, therefore non-exclusive, embodiments of an equipment for tibio-femoral arthroplasty surgery, a femoral trial component and a tibial guide for arthroplasty surgery of a tibio-femoral joint as illustrated in the accompanying drawing tables, wherein:

[0060] - figure 1 illustrates a perspective view of an equipment for tibiofemoral arthroplasty surgery according to the present invention, in a first embodiment;

[0061] - figures 2 and 3 illustrate a side view and a plan view of the equipment for tibio-femoral arthroplasty surgery of figure 1 ;

[0062] - figure 4 shows the equipment of figure 2 in use;

[0063] - figures 5-8 show a component of the equipment of figure 1 in perspective, in front view, in bottom view and in rear view;

[0064] - figure 9 shows the component of figure 4 in an assembly step with a further component of the equipment of figure 1 ;

[0065] - figure 10 illustrates a perspective view of an equipment for tibiofemoral arthroplasty surgery according to the present invention, in a second embodiment;

[0066] - figures 11 -15 show a component of the equipment of figure 10 in front and rear perspective, front view, side view and plan view;

[0067] - figure 16 illustrates a perspective view of an equipment for tibio- femoral arthroplasty surgery according to the present invention, in a third embodiment;

[0068] - figures 17-19 show a component of the equipment of figure 16 in perspective, in front view and in plan;

[0069] - figures 20-21 show side views of the component of figure 16 in two different configurations;

[0070] - figure 22 shows the component of figure 16 in use;

[0071] - figures 23a-23f schematically show a surgical procedure exploiting the equipment for tibio-femoral arthroplasty surgery according to the present invention.

[0072] Detailed description

[0073] With reference to the attached figures, an equipment for tibio-femoral arthroplasty surgery according to the present invention has been indicated overall with the number 1 .

[0074] The equipment 1 subject-matter of the present invention is used in the intra-operative step to verify the correct relative movement between tibia T and femur F during the flexion-extension movement of the leg and, consequently, the correct execution of the tibial and femoral cutting surfaces on which the definitive implant must be grafted.

[0075] In the flexion-extension movement of a non-pathological knee, a relative rotation occurs between tibia T and femur F. In particular, from extension to flexion, the femur F rotates externally relative to the tibia T rotating around the point of medial contact between tibia and femur (the so-called medial pivoting): as a consequence, the point of lateral contact between tibia and femur moves towards the posterior part of the lateral tibial plateau.

[0076] The relative rotation of the tibia and femur during the flexion-extension movement of the knee is therefore a roto-translational movement.

[0077] Looking frontally at a knee of a person in an upright position, when the leg is in extension, tibia and femur are both aligned vertically along a plane parallel to the frontal plane of the person's body (or orthogonal to the transverse plane of the person), when the leg is flexed, on the other hand, the tibia remains substantially vertical while the femur bends by 90°, orienting itself horizontally and therefore moving in a position parallel to the transverse plane of the person's body (or orthogonal to the frontal plane of the person).

[0078] During this movement there is not only the rotation of the femur around a horizontal axis orthogonal to the sagittal plane, but also a rotation around a mechanical axis of the (vertical) axis orthogonal to the distal or transverse plane. The definition of this vertical mechanical axis "V" will be explained below after describing the anatomy of a knee.

[0079] The knee is a complex joint formed by the femur, tibia, fibula and patella. The distal portion of the femur consists of the medial condyle and the lateral condyle, both lined with cartilage. The medial condyle is the innermost and closest to the sagittal plane, while the lateral condyle is in a distal position with respect to the sagittal plane of the body. Anteriorly, the two condyles form a groove, called the femoral trochlea, which has the task of housing the patella during flexion-extension of the knee. The proximal portion of the tibia, in its articular part, is called the tibial plateau, and is divided into two hemiplates, medial and lateral, lined with cartilage, which articulate respectively with the medial and lateral femoral condyles. The two tibial hemiplates are separated by two bony eminences defining the tibial spine.

[0080] The two femoral condyles are rounded protuberances placed at the distal end of the femur, and allow the latter to articulate with the opposite concavity made on the tibial plateau.

[0081] Viewed laterally, therefore, each condyle has a curvilinear shape and, specifically, the articular surface of the medial femoral condyle is approximable to a sphere. Articular surface means the outer surface portion of the femoral condyle that couples with the tibial plateau. The mechanical axis "V" (or vertical), orthogonal to the distal (or transverse) plane and around which the femur rotates in the passage from the first position of extension of the knee to the second position of flexion of the knee, passes through the centre of the sphere that can be imagined as made at the medial condyle of the femur and tangent externally to the articular surface of the medial condyle.

[0082] The geometry of the articular surfaces is such as to allow, during flexionextension movements, the external rotation of the femur, (meaning by external rotation a lateral rotation towards the outside of the body and therefore to the right for a right knee and to the left for a left knee), around the mechanical axis "V" passing through the centre of the sphere defined by the medial articular surface of the femoral condyle; the simultaneous rotation by 90° of the femur, in the passage from the extended to flexed position, involves a consequent posterior translation (therefore towards the posterior part of the leg) of the point of contact between the lateral condyle of the femur on the lateral tibial plateau, as the angle of flexion increases.

[0083] It is important to have the exact indication of the angle of rotation of the femur around the mechanical (or vertical) axis V. The anatomical amplitude of this rotation is defined, in the literature, to be equal to 20°.

[0084] In other words, with respect to the first position corresponding to the extended leg, and at which an angle value of 0° can be given, in the flexion position of the leg the femur rotates 20° outwards around the aforesaid mechanical axis "V".

[0085] The equipment 1 subject-matter of the present invention finds particular application downstream of the femoral cuts, i.e. the bone resections of the femoral condyles that allow the application of a femoral insert, and is used in the tibial bone resection step.

[0086] The equipment 1 in fact comprises a femoral trial component 2 shaped like a shell, a support body 3 and a tibial guide 4 for the tibial cut.

[0087] In some embodiments, one or more inserts 16 of varying thickness are also provided for use in a stabilization step. The femoral trial component 2 is a component that has relevant shape and dimensions corresponding to those of the definitive prosthetic insert, which the surgeon anchors to the patient's femur once the bone resections have been completed.

[0088] Its function is to allow, once anchored to the distal end of the femur F, to assess the correct movement of the prosthesis and to take reference points to perform tibial cuts (or tibial resections) at the tibial plateau, a zone where the surgeon will have to implant a tibial prosthetic insert.

[0089] The femoral trial component 2 is therefore shaped like a shell and, preferably, is made of a CroCoMo alloy or in any case the same material from which the prosthetic implant is generated.

[0090] The support body 3 is instead configured to be anchored to the femoral trial component 2 and support, during tibial cutting, the tibial guide 4.

[0091] Note that, in some embodiments, the support body 3 may be made integral with the femoral trial component 2.

[0092] The tibial guide 4 is associated with the support body 3 and comprises a plurality of fastening points 11 with a proximal end of the tibia T and a guide slot 12 crossable by a bone resection instrument.

[0093] Preferably, the femoral trial component 2 is provided with an anterior patellar portion 5 from which a medial condylar portion 6 and a lateral condylar portion 6 branch off, arranged side by side.

[0094] Preferably, the medial 6 and lateral 7 condylar portions extend arranged side by side from the anterior patellar portion 5 in the posterior direction, while remaining at a distance adapted to house, at least in part, a tibial spine.

[0095] The anterior patellar portion 5 has, in some embodiments (figures 1 -9) a complete shape, substantially shaped like the corresponding femoral prosthetic insert.

[0096] In such an embodiment, the extension of the anterior patellar portion 5 along a proximo-distal direction is greater than that of the condylar portions 6, 7. Alternatively, the anterior patellar portion 5 could only partially take up the outline of the insert, acting only as a reference for further components of the equipment, such as for example the support bar or body 3. Such an alternative is for example shown in figures 10-16.

[0097] The medial 6 and lateral 7 condylar portions have a distal 8 (or outer) and a proximal 9 (or inner) surface.

[0098] Preferably, the distal surface 8 takes up the shape of the femoral condyles and the proximal surface 9 takes up the geometry of the femoral resections.

[0099] Preferably, each condylar portion 6, 7 comprises a distal part 6b, 7b and a posterior part 6a, 7a, spaced from the anterior patellar portion 5 by the distal part 6b, 7b.

[0100] In other words, the condylar portion 6, 7 extends in a curved manner from the posterior portion 6a, 7a towards the distal part 6b, 7b and then rejoins, along an antero-posterior direction "A" to the anterior patellar portion 5.

[0101] The distal part 6b, 7b preferably has a curved outer face 8a and a substantially flat inner face 9a, lying in a distal plane (oriented horizontally or otherwise orthogonally to the mechanical axis "V").

[0102] The posterior part 6a, 7a preferably has a curved outer face 8b and a substantially flat inner face 9b, lying in a rear plane (oriented vertically, or otherwise parallel to the mechanical axis "V").

[0103] Preferably, the outer faces 8a, 8b of the posterior 6a, 7a and distal parts 6b, 7b of the condylar portions 6, 7 define the distal surface 8 of the condylar portion. This distal surface 8 has a curvilinear and, even more preferably, at least partially circular profile.

[0104] The inner faces 9a, 9b of the posterior 6a, 7a and distal 6b, 7b parts of the condylar portions 6, 7 define the proximal surface 9 of the condylar portion. This proximal surface 9 preferably has a segmented profile, defined by a broken line formed by a plurality of segments with different orientation. In the preferred embodiment, the inner faces of the posterior 6a, 7a and distal parts 6b, 7b of the condylar portions 6, 7 are connected to each other by an inclined connecting face 9c.

[0105] Preferably, the distal part 6b, 7b of each condylar portion 6, 7 comprises an attachment zone 10 for a distal end of the femur F.

[0106] More preferably, the attachment zone 10 comprises one or more through holes (or slots) 10a.

[0107] Note in this regard that each condylar portion 6, 7 extends, along the antero-posterior direction "A", between a medial edge and a lateral edge.

[0108] In a first embodiment, illustrated in figures 1 -9, said one or more through holes (or slots) 10a are made between the medial edge and the lateral edge, directly crossing the distal part 6b, 7b from the inner face 9b to the outer face 8b.

[0109] Alternatively, however, said one or more through holes (or slots) 10a could be defined by eyelets or elements placed outside the footprint of the distal part 6b, 7b.

[0110] For example, in the embodiment illustrated in figures 11 -16, the through hole 10a of the distal part 6b of the medial condylar portion 6 is placed outside a medial edge of said distal part 6b and the through hole 10a of the distal part 7b of the lateral condylar portion 7 is placed outside a lateral edge of said distal part 7b.

[0111] According to one aspect of the present invention, in at least one coupling condition between the support body 3 and the femoral trial component 2, the support body 3 is coupled to the anterior patellar portion 5 of the femoral trial implant 2 and protrudes anteriorly thereto along an anteroposterior direction "A".

[0112] In other words, the support body 3 protrudes anteriorly to the anterior patellar portion 5 of the femoral trial component 2.

[0113] Advantageously, this configuration of the equipment 1 allows the surgeon to position the tibial guide 4 and perform the cut with the limb in extension, thus being able to assess the condition of the joint at the time of maximum stress.

[0114] In the preferred embodiment, the support body 3 is decouplable from the femoral trial component 2.

[0115] Preferably, the support body 3 is made of AISI 630.

[0116] In this regard, preferably, in the coupling condition between the support body 3 and the femoral trial component 2, the support body 3 is fastened at a distal zone 5a of the anterior patellar portion 5.

[0117] On the other hand, at a proximal zone of the anterior patellar portion 5 there are slits 5b used for the pre-positioning of the femoral trial component 2.

[0118] Preferably, the femoral trial component 2 comprises at least two openings 13 for coupling with the support body 3 extending in the antero-posterior direction "A" from said anterior patellar portion 5.

[0119] These coupling openings 13 are therefore accessible anteriorly, allowing the surgeon to couple (and decouple) the support body 3 with the limb in full extension.

[0120] Preferably, the coupling openings 13 are made at the distal portion 5a of the anterior patellar portion 5.

[0121] More preferably, the coupling openings 13 extend longitudinally along the antero-posterior direction "A" between the inner face and the outer face of the distal part 6b, 7b of each condylar portion 6, 7.

[0122] Preferably, in this regard, the support body 3 comprises a plurality of coupling pins 3a, each insertable into a respective coupling opening 13.

[0123] In the preferred embodiment, the coupling openings 13 are two, one medial and one lateral.

[0124] The support body 3 preferably comprises a joining terminal 14 provided with a fork-shaped element 14a provided with two arms, each provided with one of said pins 3a.

[0125] Preferably, the fork-shaped element 14a of the joining terminal 14 has a coupling face 14b counter-shaped to the distal zone 5a of the anterior patellar portion 5 of the femoral trial component 2.

[0126] In the preferred embodiment, the distal zone 5a of the patellar portion 5 has a convexity oriented anteriorly to which a concavity of the coupling face 14b of the fork-shaped element 14a corresponds.

[0127] This coupling face 14b is placed against the distal zone 5a of the anterior patellar portion 5.

[0128] In the preferred embodiment, the support body 3 is shaped like a bar and, in the coupling condition between the support body 3 and the femoral trial component 2, extends along the antero-posterior direction "A" between the joining terminal 14 and a free terminal 15.

[0129] Thus, in such a coupling condition between the support body 3 and the femoral trial component 2, the support body 3 extends along a direction substantially orthogonal to the anterior patellar portion 5.

[0130] The tibial guide 4 is preferably slidably associated with the support body 3, so as to be inserted, and coupled with, in the antero-posterior direction "A".

[0131] Note that the guide slot 12 of the tibial guide 4 defines a cutting plane "P" located in a distal position with respect to the femoral trial component 2 and having an inclination between 70° and 110° with respect to a posterior plane in which the inner face of the posterior part 6a, 7a of the condylar portions 6, 7 lies.

[0132] Therefore, in the preferred embodiment and in an assembled condition, the equipment 1 provides for: the femoral trial component 2 having: o the posterior part 6a, 7a of the condylar portions 6, 7 with inner face lying in the rear plane; o the distal part 6b, 7b of the condylar portions 6, 7 with inner face lying in the distal plane;

[0133] - the support body 3 extends from the anterior patellar face 5, moving away therefrom in the anterior direction;

[0134] - the tibial guide 4 is coupled to the support body and its guide slot 12 defines a cutting plane "P" located in a distal position with respect to the femoral trial component 2.

[0135] Figures 11 -15 illustrate a variation of the present invention, wherein the femoral trial component 2 has an expandable configuration.

[0136] Advantageously, in this way, a single femoral trial component 2 can be used by the surgeon during testing and definition of tibial cuts, adapting it to the size of the patient and without the need to test several different components.

[0137] In this embodiment, preferably, the anterior patellar portion 5 comprises a medial half-part 51 and a lateral half-part 52 moving closer to and away from each other along a medial-lateral direction "B" to vary a medial-lateral size of the femoral trial component 2.

[0138] The medio-lateral direction "B" is transverse, preferably orthogonal, to the antero-posterior direction "A".

[0139] Furthermore, preferably, the medial-lateral direction "B" is transverse, preferably orthogonal, to the mechanical axis "V".

[0140] Preferably, each condylar portion 6, 7 is movable relative to the anterior patellar portion 5 closer to or away from the anterior-posterior direction "A" to vary an anterior-posterior size of the femoral trial component 2.

[0141] Advantageously, in this way the insert can adapt to a plurality of sizes without requiring the surgeon to test or replace it.

[0142] Preferably, in this regard, the medial half-part 51 and the lateral half-part 52 of the anterior patellar portion 5 are configured to be positioned in at least a first moved-away configuration and a second moved-closer configuration.

[0143] Preferably, therefore, locking means are provided to keep the relative position between the medial half-part 51 and the lateral half-part 52 fixed once the first moved-away configuration or the second moved-closer configuration is reached.

[0144] More preferably, the medial half-part 51 is movably connected to the lateral half-part 52 of the anterior patellar portion 5 by means of a sliding coupling provided with one or more notches coupled to one or more indentations spaced along the medial-lateral direction "B" and defining said moved-away and moved-closer positions.

[0145] Structurally, in the preferred embodiment said medial and lateral half-part 51 , 52 of the anterior patellar portion 5 each comprise a main body 51 a, 52a provided with a joining and adjustment portion 51 b, 52b extending along said medial-lateral direction "B" and connected in an adjustable manner to the joining and adjustment portion 52b, 51 b of the other medial or lateral half-part 51 , 52.

[0146] Thus, the joining and adjustment portions 51 b, 52b extend moving closer to each other and are preferably interpenetrating with each other.

[0147] Preferably, at the joining and adjustment portions 51 b, 52b the presence of a graduated scale 55 is provided to allow a quick display of the size along the medial-lateral direction "B".

[0148] More precisely, each joining and adjustment portion 51 b, 52b is slidably coupled to the joining and adjustment portion 52b, 51 b of the other lateral half-part 51 or medial half-part 52 respectively.

[0149] Preferably, the joining and adjustment portion 51 b, 52b of the medial halfpart 51 comprises a tab 57 protruding from the main body 51 a along the medial-lateral direction "B" and slidably inserted into the joining and adjustment portion 52b of the lateral half-part 52, or vice versa.

[0150] It should be noted that, preferably, the anterior patellar portion 5 of this embodiment of the femoral trial component 2 has a thickness, considered along the antero-posterior direction "A", greater than the corresponding prosthetic insert that the surgeon proceeds to implant at the end of the femoral and tibial bone resection steps.

[0151] This is to allow an interpenetration between the joining and adjustment portions 52b, 51 b without reducing the strength of the trial insert 2.

[0152] Furthermore, preferably, the anterior patellar portion 5 shows lower proximal-distal extension than the posterior part 6a, 7a of the condylar portions 6, 7. Furthermore, preferably, each joining and adjustment portion 51 b, 52b has a smaller footprint, considered along a proximal-distal direction "C", that is smaller than the respective main body 51 a, 52a in order to define a tibial spine housing port.

[0153] In other words, the anterior patellar portion 5 is preferably defined by the two main bodies 51 a, 52a of the respective medial 51 and lateral 52 halfparts, joined with a varying distance by a central bridge defined by the joining and adjustment portions 52b, 51 b and having a limited footprint with respect to the proximal-distal direction "C".

[0154] More precisely, the patellar portion 5 has a first edge 53, proximal, and a second edge 54, distal.

[0155] The distance between the first 53 and the second edge 54, considered at the two main bodies 51 a, 52a along the proximal-distal direction "C", is greater than the same distance measured at the central bridge (i.e. of the joining and adjustment portions 52b, 51 b).

[0156] The proximo-distal direction "C" is preferably transverse, more preferably orthogonal, to the antero-posterior direction "A" and the medio-lateral direction "B".

[0157] In the preferred embodiment (and in use), the proximal-distal direction "C" is substantially parallel and aligned with the mechanical axis "V".

[0158] Advantageously, in this way the "free" area delimited between the condylar portions 6, 7 and the aforesaid central bridge (i.e. the joining and adjustment portions 52b, 51 b) is sufficiently large to house the tibial spines without the need for preventive resection.

[0159] This clearly greatly facilitates the surgeon in both speed and accuracy in positioning the trial insert 2 and performing the tibial cut, not making any preventative cuts.

[0160] It should be noted that, in this embodiment, the support body 3 can be made in one piece with one of the medial 51 or lateral half-part 52 of the anterior patellar portion 5, or reversibly coupled with it by means of an engagement or coupling. The medial 51 and lateral 52 half-parts of the anterior portion 5 each comprise a connecting element 51 c, 52c extending from the main body 51 a, 52a along the antero-posterior direction "A" and slidably coupled to a respective condylar portion 6, 7 to allow adjustment of the antero-posterior size.

[0161] The connecting elements 51 c, 52c are preferably made at the second (or distal) edge 54 of the respective main body 51 a, 52a of the anterior patellar portion 5.

[0162] The connecting element 51 c, 52c protrudes from the main body 51 a, 52a along the antero-posterior direction "A" and is slidably inserted into the respective condylar portion 6, 7.

[0163] Preferably, at the connecting elements 51 c, 52c the presence of a further graduated scale 56 is provided to allow a quick display of the size along the antero-posterior direction "A".

[0164] With reference to figures 16-22, instead, a further variant of a tibial guide 4 in accordance with the equipment 1 according to the present invention is described.

[0165] This tibial guide 4 comprises a fastening body 41 and a guide body 42 which are mutually separate and movable.

[0166] The fastening body 41 is arranged to be fastened to the patient's tibia and, therefore, at least a first fastening pointH a of the plurality of fastening points 11 is provided.

[0167] The guide body 42 is instead provided with said guide slot 12 and, as mentioned, is movable relative to the fastening body 41 to vary an inclination of the cutting direction (or of the cutting plane) with respect to the fastening body 41 .

[0168] Advantageously, in this way it is extremely easy for the surgeon to attach the tibial guide 4 with the joint in extension and proceed with the "fine" adjustment of the cutting plane by operating directly on the device and not, as is the case today, by acting on the patient's limb. Note that, preferably, the guide body 42 is slidably associated with the fastening body 41 and shaped so as to move along a curvilinear direction "E". Preferably, this curvilinear direction "E" is an arc of circumference. Even more preferably, the guide body 42 has a centre of instantaneous rotation "RC" lying on the mechanical axis "V" of said tibio-femoral joint (i.e. of the limb).

[0169] Thus, the femoral trial component 2 has a central axis passing between the condylar portions 6, 7 orthogonally to a distal part 6a, 7a of the condylar portions 6, 7 themselves and corresponding, in use, to the mechanical axis V of the tibio-femoral joint. The guide body 42 is slidably associated with the fastening body 41 and shaped so as to move along said curvilinear direction "E" with a centre of instantaneous rotation lying on said central axis.

[0170] Advantageously, in this way the movement of the guide body results in a pure rotation of the cutting plane with respect to the mechanical axis "V" of the limb, without this affecting the thickness of the bone portion that is removed.

[0171] Preferably, in this regard, the fastening body 41 comprises at least one sliding surface 41 a extending along said curvilinear direction "E", while the guide body 42 comprises at least one slider 42a movable on said sliding surface 41 a between a first and a second end position.

[0172] These first and second end positions correspond, respectively, to a maximum and a minimum inclination of the cutting direction (i.e. of the cutting plane) with respect to the mechanical axis "V".

[0173] Preferably, the maximum and minimum inclination are defined by a range of ±5° with respect to an average value.

[0174] Preferably, the fastening body 41 comprises at least one pocket 44 defining a cavity 44a inside which said slider 42a slides and delimited, in a front zone thereof, by said sliding surface 41 a.

[0175] The fastening body 41 therefore comprises a main portion 48 provided with said first attachment portion 11 a from which, along said curvilinear direction "E", the sliding surface 41 a branches off.

[0176] The guide body 42 instead comprises a main portion provided with said guide slot 12 from which, along said curvilinear direction "E", the slider 42a branches off.

[0177] Preferably, moreover, the tibial guide comprises an adjustment device 43 operatively interposed between the fastening body 41 and the guide body 42 and configured to move the guide body 42 between the first and the second end position.

[0178] In the preferred embodiment, the adjustment device 43 comprises a screw 43a - lead screw 43b coupling, preferably a micrometric screw.

[0179] Other embodiments, even with ratchet or purely "manual" movement can be implemented without deviating from the spirit of the present invention.

[0180] Preferably, the screw 43a is constrained, during crossing, to the guide body 41 .

[0181] In the illustrated embodiment, the screw 43a extends along a proximal- distal direction "C" in the direction of the fastening body 41 .

[0182] Preferably, in order to allow its implementation, the screw 43a has a head accessible from a proximal side of the fastening body 41 .

[0183] Preferably, the lead screw 43b has at least a degree of rotational freedom and a degree of translational freedom to follow the movement of the screw 43a during the rota-translation of the guide body 42 along the curvilinear direction "E".

[0184] Advantageously, this makes the movement fluid, preventing the screw 43a from jamming.

[0185] In the illustrated embodiment, the lead screw 43b is slidably associated with a track 46 made in the fastening body 41 and extending along an antero-posterior direction "A".

[0186] Note that the expression "extending along an antero-posterior direction" is not intended to limit the orientation of the track to a direction parallel to the antero-posterior one, but it is intended to identify a direction whose anteroposterior component is prevalent. In order to provide the aforesaid degree of rotational freedom, moreover, the lead screw 43b is rotatably associated with the fastening body 41 to oscillate about an axis of rotation "F" oriented in a medial-lateral direction "B".

[0187] More preferably, the lead screw 43a is rotatably associated with said track 46.

[0188] In the preferred embodiment, a graduated scale 49 is provided at the slider 42a and / or the sliding surface 41 a.

[0189] Preferably, moreover, the adjustment device 43 comprises a locking element 47 operatively interposed between the fastening body 41 and the guide body 42.

[0190] The locking element 47 is selectively switchable between a release configuration, in which it allows relative movement between the fastening body 41 and the guide body 42, and a retention configuration, in which it keeps the fastening body 41 and the guide body 42 integral.

[0191] In the illustrated embodiment, the locking element 47 comprises a threaded grub screw 47a rotatably associated with the fastening body 41 and active on the guide body 42, in particular on the slider 42a.

[0192] The surgical equipment 1 subject-matter of the present invention, so far described in several embodiments all falling within the spirit of the invention, allows to perform an innovative surgical procedure, mainly characterized by the execution of tibial cuts in extension, i.e. with the joint extended along the mechanical axis "V" of the limb.

[0193] According to this procedure, schematically illustrated in figures 23a-23f, it is firstly envisaged to perform all femoral cuts preferably following a calibrated kinematic alignment technique.

[0194] At this point, the femoral trial component 2 is positioned and fastened; preferably, this is done by attaching the femoral trial component 2 by means of anterior pins (not illustrated) inserted in the corresponding slits 5b made in the anterior patellar portion 5. The femoral holes are then made through the through holes (or slots) 10a made in the attachment zone 10 of the distal part 6b, 7b of each condylar portion 6, 7.

[0195] The joint is then brought into extension.

[0196] If the femoral trial component 2 collides with the tibial eminences (or tibial spines), the procedure preferably involves performing a resection thereof.

[0197] In this regard, it should be noted that the femoral trial component 2 illustrated in figures 10-15, having narrow condylar portions and, above all, an anterior patellar portion 5 defining a tibial spine housing port, allows the step of resection of the tibial spines to be avoided, to the advantage of the speed and precision of the procedure.

[0198] Preferably, the joint in extension is then balanced.

[0199] This is preferably done by inserting one or more inserts 16 of appropriate thickness between the femoral trial component 2 and the proximal end of the tibia, so as to restore the pre-arthrosis situation of the patient by adequately tensioning the soft tissues.

[0200] At this point, the procedure preferably provides for connecting the support body 3 to the femoral trial component 2.

[0201] In more detail, the joining terminal 14 of the support body 3 is placed against the anterior patellar portion 5 of the femoral trial component 2.

[0202] Preferably, each pin 3a of the support body 3 (in particular of the arms of the fork-shaped element 14a) is inserted into a respective coupling opening 13 of the femoral trial component 2.

[0203] Note that, in the embodiments where the support body 3 is integral with the femoral trial component 2, the latter step will not be necessary.

[0204] The tibial guide 4 is then fitted into the support body 2.

[0205] In particular, the tibial guide 4 is inserted into the free terminal 15 of the support body by sliding it until reaching a position close to the anterior patellar portion 5 of the femoral trial component 2.

[0206] In particular, the tibial guide 4 is made to slide until a contact portion thereof comes into contact with the tibia itself. The references or other accessory elements are then positioned.

[0207] At this point, exploiting the device of the embodiments illustrated in figures 1-10, the knee is slightly flexed (about 10°) so that the tibia is perfectly aligned with the previously placed references.

[0208] In this embodiment, the tibia is then possibly tilted for a fine adjustment and finally the tibial guide 4 is fastened by means of the fastening points 11 to the tibia to proceed with the resection.

[0209] With reference to the embodiment illustrated in figures 16-22, however, it is possible to avoid the movement of the tibia, by firstly proceeding with attaching the fastening body 41 to the tibia and, only in a second step, preferably after removing the support body 3, with a fine adjustment of the inclination thanks to the adjustment device 43.

[0210] This procedure, as is evident, is particularly advantageous as it significantly reduces the number of movements of the limbs, allowing, moreover, to act on the joint in its loaded condition.

[0211] The invention, therefore, achieves the intended purposes and achieves important advantages.

[0212] In fact, the provision of an equipment that allows tibial cutting in extension greatly reduces the disadvantages of the prior art.

[0213] Moreover, the use of an adjustable tibial trial insert that is slim in the shapes facilitates the positioning and balancing step, while avoiding the need to proceed with the resection of the tibial spines.

[0214] In addition, the provision of an adjustable tibial guide, with inclination of the cutting plane centred on the mechanical axis of the limb and easily operated by the surgeon, allows the determination of the tibial slope to be optimised.

Claims

CLAIMS1 . Equipment for tibio-femoral arthroplastic surgery, comprising:- a femoral trial component (2) shaped like a shell and provided with an anterior patellar portion (5) from which a medial condylar portion (6) and a lateral condylar portion (7) extend, arranged side by side; each condylar portion (6, 7) comprising a distal part (6b, 7b) and a posterior part (6a, 7a), spaced from the anterior patellar portion (5) by the distal portion (6b, 7b), wherein said distal portion (6b, 7b) of each condylar portion (6, 7) comprises a fastening zone (10) for a distal end of the femur (F);- a support body (3) connectable to the femoral trial component (2);- a tibial guide (4) for the tibial cut connectable to said support body (3) and provided with:- a plurality of fastening points (11 ) for anchoring with a proximal end of the tibia (T);- a guiding slot (12) crossable by a bone resection instrument; wherein, in at least one coupling condition between the support body (3) and the femoral trial component (2), said support body (3) is coupled to the anterior patellar portion (5) of the femoral trial component (2) and protrudes anteriorly thereto along an antero-posterior direction (A).

2. Equipment according to claim 1 , wherein, in the coupling condition between the support body (3) and the femoral trial component (2), the support body (3) is fastened at a distal zone (5a) of the anterior patellar portion (5).

3. Equipment according to claim 1 , wherein, in the coupling condition between the support body (3) and the femoral trial component (2), the support body (3) extends along a direction substantially orthogonal to the anterior patellar portion (5).

4. Equipment according to any one of the preceding claims, wherein thefemoral trial component (2) comprises at least two coupling openings (13) that couple with said support body (3) extending in an antero-posterior direction (A) from said anterior patellar portion (5).

5. Equipment according to claim 4, wherein each condylar portion (6, 7) of the femoral trial component (2) has a concave proximal surface (9) and a convex distal surface (8); said coupling openings (13) extending along said antero-posterior direction (A) between the proximal surface (9) and the distal surface (8) of the distal part (6b, 7b) of each condylar portion (6, 7).

6. Equipment according to claim 4 or 5, wherein the support body (3) comprises a plurality of coupling pins (3a), each insertable into a respective coupling opening (13).

7. Equipment according to claim 6, wherein the support body (3) extends along said antero-posterior direction (A) between a joining terminal (14) and a free terminal (15); said joining terminal (13) comprising a forkshaped element (14a) provided with two arms each provided with one of said pins (3a).

8. Equipment according to claim 7, wherein said fork-shaped element (14a) of the joining terminal (14) of said support body (2) has a coupling face (14b) that is counter-shaped to the distal zone (5a) of the anterior patellar portion (5) of the femoral trial component (2); in said coupling condition between the support body (3) and the femoral trial component (2), said coupling face (14b) being placed against said distal zone (5a) of the anterior patellar portion (5) of the femoral trial component (2).

9. Equipment according to any one of the preceding claims, wherein said guiding slot (12) of the tibial guide (4) defines a cutting plane (CP) placed in a distal position from the femoral trial component (2) and having aninclination between 70° and 110° with respect to a posterior plane (B) in which the posterior part (6a, 7a) of the condylar portions (6, 7) lies.

10. Equipment according to any one of the preceding claims, wherein the medial and lateral condylar (6, 7) portions extend side by side from the anterior patellar portion (5) in a posterior direction, maintaining a distance adapted to house, at least in part, a tibial spine.11 . Equipment according to any one of the preceding claims, wherein the anterior patellar portion (5) of the femoral trial component (2) comprises a medial half-part (51 ) and a lateral half-part (52) movable closer to and away from each other in a medial-lateral direction (B) to vary a medial- lateral size of said femoral trial component (2).

12. Equipment according to any one of the preceding claims, wherein each condylar portion (6, 7) is movable closer to or away from the anterior patellar portion (5) along an antero-posterior direction (A) to vary an antero-posterior size of said femoral trial component (2).

13. Equipment according to any one of the preceding claims, wherein the tibial guide (4) comprises:- a fastening body (41 ) provided with at least one first fastening point (11 a) of said plurality of fastening points (11 );- a guide body (42) provided with said guide slot (12) and movable relative to the fastening body (41 ) to vary an inclination of said cutting direction (CP) relative to the fastening body (41 ).

14. Equipment according to claim 13, wherein the guide body (42) is slidably associated with the fastening body (41 ) and shaped so as to move along a curvilinear direction (E).

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