TIBIAL RESECTION GUIDE DEVICE

Abstract

The present disclosure relates to a guide device for tibial resection comprising a guide jig having a slot for a surgical saw, a first feeler provided for coming into contact with a point of a tibial plateau and a second feeler provided for coming into contact with a point of a tibial plateau. The first feeler and the second feeler can be rotated with respect to one another and to the guide jig around the same rotation axis and the first feeler can be translated with respect to the second feeler and to the guide jig along a first sliding direction contained within a first sliding plane. The second feeler can be translated with respect to the first feeler and with respect to the guide jig along a second sliding direction contained in a second sliding plane parallel to the first sliding plane.

Claims

1. A tibial resection guide device comprising: a guide jig comprising a slot provided for accepting and guiding a surgical saw; a first feeler provided for coming into contact with a point or an area of a tibial plate; a second feeler provided for coming into contact with a point or an area of a tibial plate; wherein the first feeler and the second feeler can be rotated with respect to one another and to the guide jig around the same rotation axis, wherein the first feeler can be translated with respect to the second feeler and to the guide jig along a first sliding direction contained within a first sliding plane, and wherein the second feeler can be translated with respect to the first feeler and to the guide jig along a second sliding direction contained within a second sliding plane parallel to the first sliding plan.

2. The tibial resection guide device according to claim 1, wherein said rotation axis, the first sliding plane and the second sliding plane have respective pre-set inclinations relative to the slot of the guide jig.

3. The tibial resection guide device according to claim 1, wherein the first sliding plane and the second sliding plane are perpendicular to said rotation axis.

4. The tibial resection guide device according to claim 1, wherein the first feeler comprises a first end portion that develops along a first contact direction, inclined with respect to the first sliding plane, the first end portion being configured to come into contact with a point or an area of a tibial plate, the projection of the first contact direction on the first sliding plane being inclined with respect to the first sliding direction.

5. The tibial resection guide device according to claim 1, wherein the second feeler comprises a first end portion that develops along a second contact direction inclined with respect to the second sliding plane, the first end portion being configured to come into contact with a point or an area of a tibial plate, the projection of the second contact direction on the second sliding plane being inclined with respect to the second sliding direction.

6. The tibial resection guide device according to claim 1, wherein the first feeler comprises a first end portion that develops along a first contact direction, inclined with respect to the first sliding plane, the first end portion of the first feeler being configured to come into contact with a point or an area of a tibial plate, the projection of the first contact direction on the first sliding plane being inclined with respect to the first sliding direction; wherein the second feeler comprises a first end portion that develops along a second contact direction inclined with respect to the second sliding plane, the first end portion of the second feeler being configured to come into contact with a point or an area of the tibial plate, the projection of the second contact, direction on the second sliding plane being inclined with respect to the second sliding direction; and wherein the first feeler is spaced apart by a pre-set distance along the rotation axis from the second feeler, the first end portion of the first feeler having an extension, in a direction parallel to the rotation axis, that is equivalent to the extension, in a direction parallel to the rotation axis, of the first end portion of the second feeler reduced by a pre-set amount.

7. The tibial resection guide device according to claim 1, comprising a support body for the first and the second feeler that can be inserted into the guide jig, the support body comprising tightening members that can be switched from one free positioning condition, in which the first and the second feeler can be rotated and translated with respect to the support body, and a locking condition, in which the first and the second feeler are held in position with respect to the support body.

8. The tibial resection guide device according to claim 7, wherein said guide jig comprises a plurality of constraining members spaced apart from one another to accept and hold the support body in different positions.

9. The tibial resection guide device according to claim 1, comprising an extramedullary or intramedullary alignment guide, said guide jig being associated with said alignment guide so that it can be moved by said alignment wide.

10. The tibial resection guide device according to claim 9, wherein the alignment guide comprises adjustment members to translate the guide jig along a direction parallel to said rotation axis and to rotate the guide jig around two axes that are perpendicular to one another and perpendicular to the rotation axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Further features and advantages of the invention will be more evident from the following description of preferred embodiments thereof made with reference to the appended drawings. In such drawings:

[0093] FIG. 1 is a perspective view of axes and planes of reference useful for better illustrating the present invention;

[0094] FIG. 2 is a perspective view of some components of a guide device for tibial resection according to the present invention;

[0095] FIG. 3 is a sagittal view of the components of FIG. 2;

[0096] FIG. 4 is a perspective view of the guide device for tibial resection of FIG. 2 applied to a proximal portion of a tibia;

[0097] FIG. 5 is a perspective view of the guide device for tibial resection of FIG. 4 in a different operating configuration;

[0098] FIG. 6 is a view on a horizontal plane of the guide device for tibial resection of FIG. 4;

[0099] FIG. 7 is a perspective view of the guide device for tibial resection of FIG. 5; and

[0100] FIG. 8 is a perspective view of some components of the guide device for tibial resection of FIGS. 4 and 5.

DETAILED DESCRIPTION

[0101] A guide device for tibial resection according to the present invention is indicated overall by number 10.

[0102] FIG. 1 indicates a sagittal plane SP, a frontal or coronal plane FP and a horizontal or transverse plane HP with reference to the patient's body.

[0103] The sagittal plane SP is substantially vertical and ideally divides the human body into two symmetrical half parts. The frontal plane FP is substantially vertical and ideally divides the human body into a front part and a rear part. The horizontal plane FP is substantially horizontal and ideally divides the human body into an upper part and a lower part. As illustrated in FIG. 1, the sagittal plane SP, the frontal plane FP and the horizontal plane HP are perpendicular to each other.

[0104] FIG. 1 also indicates a proximal-distal axis PDA, a medial-lateral axis MLA and an anteroposterior axis APA perpendicular to one another. The proximal-distal axis PDA is contained in the sagittal plane SP and in the frontal plane FP, the medial-lateral axis MLA is contained in the horizontal plane HP and in the frontal plane FP and the anteroposterior axis APA is contained in the horizontal plane and in the sagittal plane SP.

[0105] With particular reference to FIG. 2, the guide device 10 comprises a first 11 and a second feeler 12 provided to come into contact with points or areas of a tibial plateau 100.

[0106] The first feeler 11 comprises an elongated body 13 comprising a first end portion 14, a second end portion 15 opposite the first 14 and a central portion 16 that extends between the first 14 and the second 15 end portion.

[0107] The central portion 16 comprises a slot 17 for allowing the first feeler 11 to translate along a first sliding direction S1 so as vary the relative distance between the first end portion 14 and a fixed reference.

[0108] The first sliding direction S1 is contained in a first sliding plane P1, as illustrated in FIG. 2.

[0109] The second end portion 15 comprises a gripping area 18 predisposed to be gripped by a user (for example by the surgeon) in order to be able to move the first feeler 11 along the first sliding direction S1 and about a rotation axis X. The gripping area 18 is knurled (i.e. provided with a plurality of reliefs and hollows) in order to facilitate the grip thereof.

[0110] The first end portion 14 is tapered and ends with a rounded or acuminated contact area 19 provided to come into contact with a reduced area (tending to a point) of the tibial plateau 100.

[0111] The first end portion 14 extends along a first contact direction D1 which is not aligned with the first sliding direction S1 of the first feeler.

[0112] In particular, the first contact direction D1 is inclined in the medial or lateral direction with respect to the first sliding direction S1, so as to be diverted with respect to the first sliding direction S1 towards the sagittal plane SP or away from the sagittal plane SP, as is better illustrated in FIG. 6. In other words, the projection of the first contact direction D1 on the first sliding plane P1 forms a different angle A1 from zero with the first sliding direction S1. Such angle A1 can be comprised between about 5° and about 90°, preferably comprised between about 10° and about 60°, more preferably about 30°. In any case, the inclination in the medial or lateral direction and the angle A1 can be selected as a function of the main anatomy of the tibial plateau 100 and the position of the points on the tibial plateau that the surgeon decides to choose as a reference for the alignment of the guide jig.

[0113] The first contact direction D1 is also inclined in the distal direction with respect to the first sliding direction S1, so as to be diverted with respect to the first sliding direction S1 away from the horizontal plane HP, as is illustrated better in FIG. 3. In other words, the projection of the first contact direction D1 on a perpendicular plane to the first sliding plane P1 and containing the first sliding direction S1 forms a different angle A2 from zero with the first sliding direction S1. Such angle A2 can be comprised between about 5° and about 90°, preferably comprised between about 10° and about 60°, more preferably about 45°. In any case, such angle A2 can be selected as a function of the main anatomy of the tibial plateau 100 and the position of the points on the tibial plateau that the surgeon decides to choose as a reference for the alignment of the guide jig.

[0114] The second feeler 12 comprises an elongated body 20 comprising a first end portion 21, a second end portion 22 opposite the first 21 and a central portion 23 that extends between the first 21 and the second 22 end portion.

[0115] The central portion 23 comprises a slot 24 for allowing the second feeler 12 to translate along a second sliding direction S2 so as vary the relative distance between the first end portion 21 and a fixed reference.

[0116] The second sliding direction S2 is contained in a second sliding plane P2, as illustrated in FIG. 2.

[0117] The second end portion 22 comprises a gripping area 25 provided to be gripped by the surgeon in order to be able to move the second feeler 12 along the second sliding direction S2 and about the rotation axis X. The gripping area 25 is knurled (i.e. provided with a plurality of reliefs and hollows) in order to facilitate the grip thereof.

[0118] The first end portion 21 is tapered and ends with a rounded or acuminated contact area 26 provided to come into contact with a reduced area (tending to a point) of the tibial plateau 100.

[0119] The first end portion 21 extends along a second contact direction D2 which is not aligned with the second sliding direction S2 of the second feeler 12.

[0120] In particular, the second contact direction D2 is inclined in the medial or lateral direction with respect to the second sliding direction S2, so as to be diverted with respect to the second sliding direction S2 towards the sagittal plane SP or away from the sagittal plane SP, as is better illustrated in FIG. 6. In other words, the projection of the second contact direction D2 on the second sliding plane P2 forms a different angle B1 from zero with the second sliding direction S2. Such angle B1 can be comprised between about 5° and about 90°, preferably comprised between about 10° and about 60°, more preferably about 30°. In any case, the inclination in the medial or lateral direction and the angle B1 can be selected as a function of the main anatomy of the tibial plateau 100 and the position of the points on the tibial plateau that the surgeon decides to choose as a reference for the alignment of the guide jig.

[0121] The second contact direction D2 is also inclined in the distal direction with respect to the second sliding direction S2, so as to be diverted with respect to the second sliding direction S2 away from the horizontal plane HP, as is illustrated better in FIG. 3. In other words, the projection of the second contact direction D2 on a perpendicular plane to the second sliding plane P2 and containing the second sliding direction S2 forms a different angle B2 from zero with the second sliding direction S2. Such angle B2 can be comprised between about 5° and about 90°, preferably comprised between about 10° and about 60°, more preferably about 45°. In any case, such angle B2 can be selected as a function of the main anatomy of the tibial plateau 100 and the position of the points on the tibial plateau that the surgeon decides to choose as a reference for the alignment of the guide jig.

[0122] For example, in the case of an assisted and controlled alignment of the guide device 10 with the patient's varus/valgus angle, the first contact direction D1 of the first end portion 14 of the first feeler 11 can be inclined in the medial direction and the second contact direction D2 of the first end portion 21 of the second feeler 12 can be selected inclined in the lateral direction (or vice versa), so that the two first end portions 14, 21 are substantially converging.

[0123] In the case of an assisted and controlled alignment of the guide device 10 with the patient's slope angle, the first contact direction D1 of the first end portion 14 of the first feeler 11 can be inclined in the same direction as the second contact direction D2 of the first end portion 21 of the second feeler 12.

[0124] The guide device 10 further comprises a support body 27 for the first 11 and the second feeler 12.

[0125] The support body 27 has a substantially cylindrical shape and enables the first 11 and the second feeler 12 to rotate about the common rotation axis X.

[0126] The rotation axis X is substantially aligned with a proximal-distal direction.

[0127] The first feeler 11 is inserted, through the slot 17, into a central portion 28 of the support body 27 which has dimensions such as to allow the slot to slide along the first sliding direction S1 with respect to the support body 27. The central portion 28 of the support body 27 is provided with a shoulder 29 on which the central portion 16 of the first feeler 11 rests (FIG. 3). The shoulder 29 defines an end stop at the degree of insertion of the first feeler 11 on the support body 27.

[0128] The second feeler 12 is also inserted, through the slot 24, into the central portion 28 of the support body 27 so as to be superposed with the first feeler 11. Between the first feeler 11 and the second feeler 12 an anti-friction washer 30 is positioned on which the second feeler 12 rests (FIG. 3). The anti-friction washer 30 defines an end stop at the degree of insertion of the second feeler 11 on the support body 27.

[0129] The support body 28 comprises tightening members 31 that can be switched from a free positioning condition to a locking condition. In the free positioning condition, the tightening members 31 enable free rotation about the rotation axis X of the first 11 and the second feeler 12 and free translation along the respective first S1 and second S2 sliding direction of the first 11 and second feeler 12. In the locking condition the tightening members 31 hold in position, by friction, the two feelers with respect to the support body 27. An example of tightening members 31 may be a presser element (for example a spring) coaxial to the support body 27 that by pressing the second feeler 12 on the first feeler 11 in the parallel direction to the rotation axis X locks by friction the two feelers in the position reached. A person skilled in the art is however aware that different types of tightening members 31 may be used for the purpose.

[0130] The guide device 10 comprises a guide jig 32 provided with constraining members 33 to accept and hold the support body 27 in a releasable way.

[0131] The constraining members 33 comprise a plurality of seats 34 predisposed to accept and retain an end portion 35 of the support body 27. The seats 34 are placed on an upper surface of the guide jig 32. The seats 34 are placed at a distance from one another so that the surgeon can choose the most suitable seat, and therefore the most suitable relative position between the feelers 11, 12 and the guide jig 32, as a function of the anatomy of the patient's tibial plateau and the points on the tibial plateau that the surgeon chooses to contact.

[0132] The end portion 35 of the support body 27 can be inserted to measure in any of the seats 34 so that the support body 27 is integral with the guide jig 32. In other words, when the support body 27 is inserted into the constraining members 33, the support body 27 cannot perform any translations with respect to the guide jig 32. Preferably, when the support body 27 is inserted into the constraining members 33, the support body 27 can rotate about the rotation axis X with respect to the guide jig 32 to facilitate the assembly operations of the support body on the guide jig 32.

[0133] Each seat 34 comprises an abutment 36 for the end portion 35 of the support body 27 which defines an end stop for the insertion in a parallel direction to the rotation axis X of the support body 27 in the seat 34. The abutment 36 further defines the height of the two feelers 11, 12 with respect to the guide jig 32. It is to be noted that such height is constant and cannot be changed once the support body is inserted into the constraining members 33.

[0134] Inside the end portion 35 of the support body 27 a peg may be provided (not illustrated) that is snap fitted into a housing with an arched extension (not illustrated) obtained in each seat 34, so as to prevent translations of the support body 27 with respect to the guide jig 32 along the rotation axis X. A person skilled in the art can however understand that other types of constraining mechanisms can be used for the purpose.

[0135] In any case, the support body 27 comprises a release mechanism 37 for removing the support body from the seat 34 in the guide jig 32. In the embodiment illustrated in the appended figures, the release mechanism 37 comprises a button 38 which acts on the constraining mechanism. By way of example, the button 38 can act on a spring (not illustrated) active on the peg of the end portion 35 of the support body for disengaging it from the housing in the seat 34.

[0136] The guide jig 32 further comprises a slot 39 predisposed to accept and guide a surgical saw adapted for tibial resection. The slot 39 crosses along a cutting plane CP the guide jig 32 so as to enable the surgical saw to cross the guide jig 32. The cutting plane CP is perpendicular to the rotation axis X when the support body 27 is fitted onto the guide jig 32.

[0137] The guide jig 32 is provided with a plurality of through holes 40 (better illustrated in FIGS. 4 and 8) which cross the guide jig 32 along a substantially perpendicular direction to the rotation axis X. In other words, the through holes 40 extend substantially parallel to the cutting plane CP. The through holes 40 are configured to accept anchoring nails 101 (depicted in FIG. 8) to constrain the guide jig 32 to the patient's tibia, as will be better illustrated below.

[0138] In the embodiment illustrated in the appended drawings, the guide device 10 comprises an extramedullary alignment guide 41 for positioning the guide jig 32 with respect to the patient's tibia.

[0139] The alignment guide 41 comprises an anchoring portion 42 placed in a distal position and predisposed to be constrained to the patient's ankle and a main portion 43 predisposed to be constrained to the guide jig 32 (FIG. 7). The extension in the proximal-distal direction of the alignment guide 41 is substantially equal to the length of the patient's tibia.

[0140] The anchoring portion 42 comprises a flexible element 44 having two ends 44a, 44b, removably constrained to the alignment guide 41 at the anchoring portion 42. The flexible element 44 is predisposed to be fastened around the patient's ankle, closing in a ring configuration.

[0141] The main portion 43 comprises coupling members 45 placed in a proximal position and predisposed to cooperate with the guide jig 32 to constrain the latter to the alignment guide 41 and lock any relative movement between the alignment guide 41 and the guide jig 32. The coupling members 45 are placed on the opposite side of the alignment guide 41 with respect to the anchoring portion 42.

[0142] As better illustrated in FIG. 5, the coupling members 45 comprise a slide 46 which is integral with the alignment guide 41 insertable in a groove 47 provided on the guide jig 32. The insertion of the slide 46 in the groove 47 locks the relative movement between the guide jig 32 and the alignment guide 41 in the medial-lateral direction and in the proximal-distal direction. The coupling members 45 are further provided with a locking and release device 48 that can be switched between a locking condition, in which it prevents the movement of the guide jig 32 with respect to the alignment guide 41 in the anteroposterior direction and therefore prevents the removal of the guide jig 32 from the alignment guide 41, and a release condition in which it enables the sliding in the anteroposterior direction of the guide jig 32 with respect to the alignment guide 41 and therefore the removal of the guide jig 32 from the alignment guide 41.

[0143] In the embodiment of FIG. 5, the locking and release device 48 comprises a movable slider 49 that can be actuated by the surgeon and enables, as a function of the position assumed, the slide 46 to be locked by mechanical interference inside the groove 47 and the sliding of the slide 46 inside the groove 47 (allowing the removal of the slide 46 from the groove 47).

[0144] The alignment guide 41 further comprises adjustment members 50 (indicated in FIG. 7) that enable the relative position of the guide jig 32 to be varied with respect to the patient's tibia.

[0145] In particular, the adjustment members 50 enable the guide jig 32 to be translated in the proximal-distal direction, the guide jig to be rotated about an anteroposterior direction and the guide jig 32 to be rotated about a medial-lateral direction.

[0146] For that purpose, the adjustment members 50 act between the anchoring portion 42 and the main portion 43 of the alignment guide 41 to vary the mutual position between these two portions.

[0147] In particular, the adjustment members 50 comprise a first translation mechanism 51 which enables the main portion 43 to translate in the medial-lateral direction with respect to the anchoring portion 42. The first translation mechanism 51 can for example comprise a guide rail (not illustrated) associated with the anchoring portion 42 or the main portion 43 and a sliding groove (not illustrated) for the guide rail associated with the main portion 43 or with the anchoring portion 42, so that the sliding of the guide rail within the sliding groove determines a translation in the medial-lateral direction of the main portion 43 with respect to the anchoring portion 42. The first translation mechanism 51 can also comprise a locking pin (not illustrated) for locking the guide rail with respect to the sliding groove.

[0148] Preventing a translation of the guide jig 32 in the medial-lateral direction, for example by retaining it with a hand or fixing the cutting jig 32 to the tibia with a fixing nail, the translation in the medial-lateral direction of the main portion 43 with respect to the anchoring portion 42 causes a rotation of the guide jig 32 about an anteroposterior direction. In fact, it is to be noted that the anchoring portion 42 of the alignment guide 41 cannot translate (being constrained to the patient's ankle) but can rotate (given the constraint actuated by the flexible element 44) and therefore the relative translation between the main portion 43 and the anchoring portion 42 (when the guide jig 32 cannot translate) causes a rotation of the alignment guide 41 and therefore of the guide jig 32.

[0149] The adjustment members 50 further comprise a second translation mechanism 52 which enables the main portion 43 to translate in the anteroposterior direction with respect to the anchoring portion 42. In particular, the second translation mechanism 52 enables the main portion 43 to translate in the anteroposterior direction with respect to the first translation mechanism 51 (which cannot perform movements in the anteroposterior direction with respect to the anchoring portion 42). The second translation mechanism 52 can comprise a guide rail (not illustrated) associated with the first translation mechanism 51 or with the main portion 43 of the main portion of the alignment guide 41 and a sliding groove (not illustrated) for the guide rail associated with the main portion 43 or with the first translation mechanism 51, so that the sliding of the guide rail within the sliding groove determines a translation in the anteroposterior direction of the main portion 43 with respect to the first translation mechanism 51 and therefore with respect to the anchoring portion 42. The second translation mechanism 52 can also comprise a locking pin (not illustrated) for locking the guide rail with respect to the sliding groove.

[0150] Preventing a translation of the guide jig 32 in the anteroposterior direction, for example by retaining it with a hand or fixing the cutting jig 32 to the tibia with a fixing nail, the translation in the anteroposterior direction of the main portion 43 with respect to the anchoring portion 42 causes a rotation of the guide jig 32 about a medial-lateral direction. In fact, it is to be noted, also in this case, that the anchoring portion 42 of the alignment guide 41 cannot translate (being constrained to the patient's ankle) but can rotate (given the constraint actuated by the flexible element 44) and therefore the relative translation between the main portion 43 and the anchoring portion 42 (when the guide jig 32 cannot translate) causes a rotation of the alignment guide 41 and therefore of the guide jig 32.

[0151] The adjustment members 50 further comprise a third translation mechanism 53 which enables the main portion 43 to translate in the proximal-distal direction with respect to the anchoring portion 42. In particular, the third translation mechanism 53 enables the main portion 43 to translate in the proximal-distal direction with respect to the first 51 and the second translation mechanism 52 (which cannot perform movements in the proximal-distal direction with respect to the anchoring portion 42). The third translation mechanism 53 can comprise a guide rail (not illustrated) associated with the second translation mechanism 52 or with the main portion 43 and a sliding groove (not illustrated) for the guide rail associated with the main portion 43 or with the second translation mechanism 52, so that the sliding of the guide rail within the sliding groove determines a translation in the proximal-distal direction of the main portion 43 with respect to the second translation mechanism 52 and therefore with respect to the anchoring portion 42. The third translation mechanism 53 can also comprise a locking pin (not illustrated) for locking the guide rail with respect to the sliding groove. The third translation mechanism 53 can further comprise a fine adjustment device 54 (depicted in FIG. 7) for precisely adjusting the translation in the proximal-distal direction of the main portion 43 with respect to the anchoring portion 42 of the alignment guide 41.

[0152] The translation in the proximal-distal direction of the main portion 43 causes a translation in the same direction and orientation as the guide jig 32.

[0153] The guide device 10 can be used in a tibial resection operation that requires a kinematic alignment of the guide jig 32 (i.e. of the slot 39 for the insertion of the surgical blade) with the patient's native joint line.

[0154] In particular, should the surgeon wish to perform an assisted and controlled kinematic alignment of the guide jig 32 with the patient's varus/valgus angle, a tibial resection method may be as follows.

[0155] A first 11 and a second feeler 12 are selected that have first end portions 14, 21 provided with respective first D1 and second contact directions D2 able, when the feelers 11, 12 are mounted on the guide jig 32, to reach the selected points of the tibial plateau.

[0156] The length of the first end portions 14, 21 of the two feelers 11, 12 is selected so as to reach the same height (when the feelers are in use) or to compensate for any cartilaginoid and/or bone wear of the tibial plateau.

[0157] The two feelers are then mounted on the support body 27 so that the first feeler 11 lies below the second feeler 12. The support body 27 is assembled on the guide jig 32.

[0158] The alignment guide 41 is constrained, through the flexible element 44, to the patient's ankle.

[0159] The guide jig 32 with the support body and the feelers 11, 12 is brought to an anterior and proximal portion of the patient's tibia. Such portion of tibia has been previously exposed, with conventional operating techniques, to enable the resection.

[0160] The guide jig 32 is coupled to the alignment guide 41 and the surgeon positions the first and the second feeler 11, 12 at areas or points of the medial condyle and of the lateral condyle that identify, on a parallel plane to the front plane, the patient's native joint line.

[0161] The alignment guide 41 is adjusted by acting on the adjustment members 50 for creating an optical alignment of the guide jig 32 (and in particular of the slot 39) with the slope angle of the patient's tibia.

[0162] During this step, the mentioned alignment is not assisted and controlled, i.e. it is performed by looking for and finding an alignment through an optical comparison between the orientation of the slot 39 and an imaginary line that joins two separate points in the anteroposterior direction of the medial condyle and of the lateral condyle that the surgeon considers to be representative of the slope angle.

[0163] The alignment of the guide jig 32 with the slope angle is performed by acting on the second translation mechanism 52 with the guide jig 32 which cannot translate in the anteroposterior direction.

[0164] After obtaining the desired alignment, the surgeon acts on the adjustment members 50 to obtain an assisted and controlled alignment of the guide jig 32 (i.e. of the slot 39) with the native varus/valgus angle and to position the guide jig at a predetermined cutting height.

[0165] In particular, the surgeon acts on the first adjustment mechanism 51 and on the third adjustment mechanism 53 (and possibly on the fine adjustment device 54) until the contact areas 19, 26 of the first 11 and the second feeler 12 are in contact with pre-selected areas or points of the medial condyle or the lateral condyle, as schematically illustrated in FIG. 4.

[0166] At this point, in some or all of the through holes 40 in the guide jig 32, anchoring nails 101 are inserted, as illustrated in FIG. 8 and subsequently the support guide 27 and with them the first and the second feeler 11, 12 are removed from the guide jig 32. The anchoring nails 101 are screwed into the patient's tibia so that the guide jig 32 is perfectly integral with the tibia and cannot move with respect to it.

[0167] The alignment guide 41 can be removed and the slot 39 of the guide jig 32 can be engaged by a surgical saw for performing the tibial resection. During the resection, the slot 39 acts as a guide for the inclination of the surgical saw with respect to the tibia.

[0168] Should the surgeon wish to perform an assisted and controlled kinematic alignment of the guide jig 32 with the patient's slope angle, a tibial resection method may be as follows.

[0169] A first 11 and a second feeler 12 are selected that have first end portions 14, 21 provided with respective first D1 and second contact directions D2 able, when the feelers 11, 12 are mounted on the guide jig 32, to reach the selected points of the tibial plateau.

[0170] The length of the first end portions 14, 21 of the two feelers 11, 12 is selected so as to reach the same height (when the feelers are in use) or to compensate for any cartilaginoid and/or bone wear of the tibial plateau.

[0171] The two feelers 11, 12 are then mounted on the support body 27 so that the first feeler 11 lies below the second feeler 12. The support body 27 is assembled on the guide jig 32.

[0172] The alignment guide 41 is constrained, through the flexible element 44, to the patient's ankle.

[0173] The guide jig 32 with the support body 27 and the feelers 11, 12 is brought to an anterior and proximal portion of the patient's tibia. Such portion of tibia has been previously exposed, with conventional operating techniques, to enable the resection.

[0174] The guide jig 32 is coupled to the alignment guide 41 and the surgeon positions the first and the second feeler 11, 12 at the pre-selected points on the same condyle (medial or lateral) separated in the anteroposterior direction.

[0175] The alignment guide 41 is adjusted by acting on the adjustment members 50 for creating an optical alignment of the guide jig 32 (and in particular of the slot 39) with the varus/valgus angle of the patient's tibia.

[0176] During this step, the mentioned alignment is not assisted and controlled, i.e. it is performed by looking for and finding an alignment through an optical comparison between the orientation of the slot 39 and an imaginary line that joins two points of the medial condyle and of the lateral condyle that the surgeon considers to be representative of the native varus/valgus angle.

[0177] The alignment of the guide jig 32 with the varus/valgus angle is performed by acting on the first translation mechanism 51 with the guide jig 32 which cannot translate in the medial-lateral direction.

[0178] After obtaining the desired alignment, the surgeon acts on the adjustment members 50 to obtain an assisted and controlled alignment of the guide jig 32 (i.e. of the slot 39) with the slope angle and to position the guide jig at a predetermined cutting height.

[0179] In particular, the surgeon acts on the second adjustment mechanism 52 and on the third adjustment mechanism 53 (and possibly on the fine adjustment device 54) until the contact areas 19, 26 of the first 11 and the second feeler 12 are in contact with pre-selected points of the medial condyle or the lateral condyle, as schematically illustrated in FIG. 5.

[0180] At this point, in some or all of the through holes 40 in the guide jig 32, anchoring nails 101 are inserted, as illustrated in FIG. 8 and subsequently the support guide 27 and with them the first and the second feeler 11, 12 are removed from the guide jig 32. The anchoring nails 101 are screwed into the patient's tibia so that the guide jig 32 is perfectly integral with the tibia and cannot move with respect to it.

[0181] The alignment guide 41 can be removed and the slot 39 of the guide jig 32 can be engaged by a surgical saw for performing the tibial resection. During the resection, the slot 39 acts as a guide for the inclination of the surgical saw with respect to the tibia.

[0182] Obviously, a person skilled in the art, for the purpose of fulfilling specific and contingent needs, can make numerous modifications and variations to the invention described above, such as, for example, to have the guide device be operated by an authorised user instead of a surgeon, all however contained within the scope of protection of the present invention as defined by the following claims.