Tibial cutting guide positioning aid device

Abstract

A device (1) for assisting in positioning a tibial cutting guide, comprising an alignment post (4) extending along a main axis of the device (1), and on which a tibial cutting guide block (3), provided with a tibial cutting guide (16) mounted on a tibial cutting guide support (32), is movable in translation along the main axis, the device (1) being characterized in that the tibial cutting guide block (3) is provided with a system for adjusting the tibial slope of the tibial cutting guide (16) and / or a system for adjusting the degree of tibial varus-valgus of the tibial cutting guide (16). Figure 1

Description

Title of the invention: Device for assisting in positioning a tibial cutting guide

[0001] The invention relates to the field of knee prostheses. In particular, it relates to a device for assisting in the positioning of a tibial cutting guide, enabling in particular the performance of a tibial cut in preparation for the operation of fitting the prosthesis.

[0002] The knee is the joint between the femur and the tibia. The patella is a third bony part located towards the front and is part of the joint. The sliding articular surfaces are covered with cartilage and numerous muscles and tendons surround this joint and allow the knee to be extended and bent.

[0003] Osteoarthritis is a wear and tear of the cartilage present at the sliding surfaces. This wear and tear is also accompanied by changes in the femur, tibia and patella. These changes cause pain in the knee as well as stiffness and difficulty walking, requiring the extensive use of anti-inflammatories, painkillers and sometimes even a cane.

[0004] The wear and tear of the cartilage is irreversible and osteoarthritis does not heal spontaneously. The natural progression is towards a progressive deterioration of the joint, an increasingly significant limitation of mobility and increasingly difficult walking.

[0005] Anti-inflammatory and painkillers that may initially be sufficient eventually become ineffective. This is when the question of surgery arises.

[0006] The aim of the surgical operation is to relieve pain, restore joint mobility and resume normal walking, by removing areas of bone and cartilage that are worn, and replacing them with artificial parts having the same shapes.

[0007] An incision is made at the anterior part of the knee. A passage is made through the inner part of the kneecap to access the joint, then the worn cartilage is removed. The femur, tibia, and kneecap are then prepared to receive the prosthesis.

[0008] Bone preparation can begin with femoral preparation, which allows all of the cartilage to be removed and the shape of the femur to be adapted so that it can receive the prosthesis. This preparation is carried out in particular using cutting templates of a size adapted to the operated femur.

[0009] To do this, a specific instrument is used, which is a cutting guide and which allows a distal femoral cut to be made. This cut will then serve as a positioning reference for the cutting template of the size adapted to the implant to make the smallest possible cuts at the level of the femur and to prepare the placement of the femoral implant of the prosthesis.

[0010] The surgeon successively performs the distal, anterior, then posterior femoral cuts and finally the chamfers. The angulation and rotational orientation of these cuts is personalized for each patient and determined by the imaging examinations carried out before the operation.

[0011] A tibial cutting guide is then positioned on the anterior surface of the tibia using an extra- or intra-medullary tibial aiming system and the tibial cut removing the worn cartilage is made. After checking with plastic trial implants that the thickness and orientation of the cuts made were correct, the final implants are put in place, starting with the positioning of the tibial implant on which a polyethylene insert is fixed. Once the femoral implant is in place, the sliding of the femoral implant on the polyethylene insert allows movements of the knee. The worn cartilage of the patella can also be removed. A polyethylene patellar implant is fixed on the articular surface allowing painless sliding of the patella along the femoral implant during movements of the knee.

[0012] Two parameters are important for the positioning of the tibial cutting guide relative to the tibia: the tibial slope and the degree (or angle) of tibial varus-valgus (correction of the HKA angle (hip / knee / ankle in English)).

[0013] The tibial slope, also called the posterior tibial slope, is the inclination of the tibial plateau in the sagittal plane.

[0014] It is known to carry out the adjustment of the tibial slope and the degree of tibial varus-valgus from an adjustment system located at the level of the malleoli. This adjustment has the disadvantage of being imprecise, because it is carried out indirectly by linear antero-posterior movements (for the adjustment of the tibial slope) and medico-lateral movements (for the adjustment of the varus-valgus) of the adjustment system, without any notion of angular correction.

[0015] The invention provides an ancillary device, in particular a device for assisting in positioning a tibial cutting guide, which makes it possible to precisely adjust the tibial slope and / or the degree of tibial varus-valgus.

[0016] The invention thus relates to a device for assisting in the positioning of a tibial cutting guide, comprising an alignment post extending along a main axis of the device, and on which a tibial cutting guide block, provided with a cutting guide tibial mounted on a tibial cutting guide support, is movable in translation along the main axis.

[0017] In the device according to the invention, the tibial cutting guide block is provided with a system for adjusting the tibial slope of the tibial cutting guide and / or a system for adjusting the degree of tibial varus-valgus of the tibial cutting guide.

[0018] Thus, positioning the adjustment system directly in the tibial cutting guide block allows for precise adjustment of the tibial slope and / or the degree of tibial varus-valgus.

[0019] The tibial cutting guide block is preferably provided with a system for adjusting the tibial slope of the tibial cutting guide and a system for adjusting the degree of tibial varus-valgus of the tibial cutting guide.

[0020] The tibial cutting block may comprise a tibial cutting guide block body extending generally in a plane orthogonal to the main axis of the device, said body extending in a longitudinal direction, towards the tibia.

[0021] The tibial slope adjustment system may comprise a transverse axis rotational mounting of a first part of the tibial cutting guide support around a second part of the tibial cutting guide support, the second part of the tibial cutting guide support being, during this transverse axis rotation, integral with the tibial cutting guide block body.

[0022] The system for adjusting the degree of tibial varus-valgus may comprise a rotational mounting, with a longitudinal axis, of the second part of the tibial cutting guide support around the tibial cutting guide block body, the second part of the tibial cutting guide support being, during this rotation with a longitudinal axis, integral with the first part of the tibial cutting guide support.

[0023] The tibial cutting guide block body may comprise a first portion secured to the alignment post and a second portion longitudinally movable in translation relative to the first portion.

[0024] The first part of the tibial cutting guide support may comprise a first movable arm, secured to the second part of the tibial cutting guide support in a locked position of the first movable arm and not secured to the second part of the tibial cutting guide support in an unlocked position of the first movable arm, the first movable arm being, in its unlocked position, movable in rotation around the second part of the tibial cutting guide support.

[0025] The first movable arm can be lockable, via an adjustment button of the first movable arm, on a first graduated element of the second part of the tibial cutting guide support.

[0026] The second part of the tibial cutting guide support may comprise a second movable arm, integral with the second part of the tibial cutting guide block body. tibial cutting in a locked position of the second movable arm and not secured to the second part of the tibial cutting guide block body in an unlocked position of the second movable arm, the second movable arm being, in its unlocked position, movable in rotation around the second part of the tibial cutting guide block body.

[0027] The second movable arm may be lockable, via an adjustment knob of the second movable arm, on a second graduated element of the second part of the tibial cutting block body.

[0028] The first portion of the tibial cutting guide block body may include a wheel having a thread cooperating with a thread of the alignment post to form a screw-nut system.

[0029] The wheel may comprise a button, the actuation of which is capable of separating the tapping from the thread.

[0030] The alignment post may be connected at its lower end to an ankle brace (or clamp) and may be connected at its upper end to a pin fixation arm. Alternatively, the pins may be replaced by a rod capable of sliding vertically and intended to be positioned in the diaphyseal axis of the tibia.

[0031] The alignment post may include a distal rod and a proximal tube within which the distal rod may slide.

[0032] The thread may belong to the proximal tube.

[0033] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of a non-limiting example of implementation, made with reference to the appended figures in which:

[0034] [Fig-1] is a general perspective view of a positioning aid device tibial cutting guide according to the invention,

[0035] [Fig.2] is a partial side view of the device, in a first embodiment realization,

[0036] [Fig.3] is a partial side view of the device, in a second mode of realization,

[0037] [Fig.4] is a top perspective view of a tibial cutting guide block of the device,

[0038] [Fig.5] is a side perspective view of the tibial cutting guide block,

[0039] [Fig.6] is a perspective view of a first portion of a guide block body tibial cutting of the device,

[0040] [Fig.7] is a first detail view of the tibial cutting guide block body,

[0041] [Fig.8] is a second detail view of the tibial cutting guide block body,

[0042] [Fig.9] is a partial side view of the device, illustrating a vertical displacement of the tibial cutting guide block, according to a first embodiment,

[0043] [Fig. 10] is a partial side view of the device, illustrating a vertical displacement of the tibial cutting guide block, in accordance with a second embodiment,

[0044] [Fig. 11] is a partial side view of the device, illustrating longitudinal movement of the tibial cutting guide block,

[0045] [Fig. 12] is an exploded perspective view of the device,

[0046] [Fig. 13] is a partial side view of the device, illustrating an adjustment system of the tibial slope of the tibial cutting guide of the device,

[0047] [Fig. 14] is a detailed view of the tibial slope adjustment system,

[0048] [Fig. 15] is a partial side view of the device, illustrating an adjustment system the degree of tibial varus-valgus of the tibial cutting guide of the device,

[0049] [Fig. 16] is a detailed view of the varus-valgus degree adjustment system,

[0050] [Fig. 17] is a top perspective view of the tibial cutting guide block of the device,

[0051] [Fig. 18] is a perspective view of a tibial cutting guide holder of the device, and

[0052] [Fig. 19] is an exploded perspective view of the tibial cutting guide holder.

[0053] As illustrated in [Fig.l], a tibial cutting guide positioning aid device 1 comprises a frame 2 and a tibial cutting guide block 3.

[0054] The device 1 extends in a main vertical direction Z, a longitudinal direction X towards the tibia, and a transverse direction Y.

[0055] The frame 2 comprises an alignment post 4 connected at its lower end to a pin 5 and at its upper end to a fixing arm 6 with pins 7.

[0056] The alignment post 4 extends vertically. It comprises a distal rod 8, a proximal tube 9 inside which the distal rod 8 can slide. The terms "distal" and "proximal" refer to the tibial cutting guide block 3. The height of the alignment post 4 can be adjusted by sliding the proximal tube 9 relative to the distal rod 8. A thumbscrew 10 allows the proximal tube 9 to be locked onto the distal rod 8 once the height has been adjusted.

[0057] The proximal tube 9 is provided with a threaded zone 11 allowing the height of the tibial cutting block 3 to be adjusted relative to the proximal tube 9.

[0058] The ankle brace 5 is a malleolar clamp allowing the lower end of the guide 1 to be positioned around the malleolus. The ankle brace 5 is provided with a rod 5a which can slide longitudinally in a lower part of the distal rod 8. The ankle brace 5 also comprises two arms 5b. With the two arms 5b in the open position, the entire device 1 is pushed against the tibia, and the arms 5b are caused to close around the ankle joint.

[0059] The longitudinal position of the ankle brace 5 can be adjusted by pressing a button 12 on the end of the distal rod 8. The button 12 can be provided with a pin vertically positionable in holes in the rod 5a of the ankle brace 5. By releasing the button 12, the pin is inserted into an hole which locks the ankle brace 5 on the alignment post 4.

[0060] At the upper end of the device 1, the fixation arm 6 may be provided with pins 7 oriented vertically and intended to be inserted into the upper end of the tibia. Alternatively, the pins may be replaced by a rod capable of sliding vertically and intended to be positioned in the diaphyseal axis of the tibia in the case of an intramedullary aim.

[0061] The longitudinal adjustment of the fixing arm 6 is carried out by sliding the arm 6 axially in an upper part of the proximal arm 9. A button 13 or a lever makes it possible to lock the fixing arm 6 on the proximal arm 9.

[0062] Thus, in a first embodiment, which corresponds to an extramedullary aim, the alignment post 4 is positioned parallel to the diaphyseal axis A of the tibia 14 ([Fig.2]). The fixing arm 6 is provided with the pins 7.

[0063] In a second embodiment, illustrated in [Fig. 3], and which corresponds to an intramedullary aim, the alignment post 4 is also positioned parallel to the diaphyseal axis A of the tibia 14, but this time the ankle brace can be dispensed with. A rod 20 is inserted into the tibia 14, along the diaphyseal axis A ([Fig. 3]).

[0064] The remainder of the description is devoted to the tibial cutting guide block 3.

[0065] The tibial cutting guide block 3 comprises a cutting guide block body tibial 15 which is articulated to a tibial cutting guide support 32 receiving a tibial cutting guide 16 (figures 4 and 5). The tibial cutting guide block body 15 extends generally in a horizontal plane orthogonal to the main axis of the device 1. In particular, the tibial cutting guide block body 15 extends longitudinally, in the direction of the tibia, on either side of the alignment post 4.

[0066] The tibial cutting guide block body 15 comprises a first portion 15a and a second portion 15b.

[0067] The first part 15a, illustrated in Figures 6 to 8, is integral with the proximal tube 9, in particular via the thread 11 of the proximal tube 9. The first part 15a is provided for this purpose with a wheel 17 having a thread 18 cooperating with the thread 11 of the proximal tube 9 by forming a screw-nut system. Thus, by turning the wheel 17 around the thread 11, the vertical position of the first support 15 can be adjusted relative to the alignment post 4 ([Fig.9]). The first part 15a advantageously comprises one or more guide pins 15a2 housed in a vertical groove 11a formed in the thread 11, which makes it possible not to modify the longitudinal and transverse orientation of the first support 15a when turning the wheel 17.

[0068] The wheel 17 advantageously comprises a button 19 which is provided with the thread 18. The thread 18 may be a partial thread, formed only on a lateral part of the central bore of the button 19. Thus, by pushing the button 19 laterally, the thread 18 is separated from the thread 11 and it is possible to carry out a rapid rise of the first part 15a relative to the alignment post 4 by vertically translating the wheel 17 ([Fig. 10]). By releasing the button 19, the thread 18 cooperates again with the thread 11 and it is possible to carry out a more precise adjustment of the vertical position of the tibial cutting block 3 by turning the wheel 17.

[0069] The first part 15a comprises a lower housing receiving the wheel 17 and a housing located at a distance from the proximal tube 9 and receiving a button 21 making it possible to adjust the longitudinal position of the second support 15b relative to the first support 15a ([Fig. 11]). The button 21 is for example provided at each of its transverse ends with an edge capable of cooperating with a notched zone located under rails 23 of the second support 15b.

[0070] The second part 15b is mounted to slide in longitudinal translation relative to the first support 15a. For this purpose, the rails 23 of the second part 15b can slide inside longitudinal channels 15al of the first part 15a ([Fig.6]). The rails 23 extend longitudinally, on either side of the proximal tube 9. The insertion of the rails 23 into the channels 15al of the first part 15a means that the second part 15b remains integral with the first part 15a during a vertical translation of the first part 15a under the rotational actuation of the wheel 17 or by pressing the button 19 and translating the wheel 17 vertically.

[0071] On the side of the tibial cutting guide support 32, the ends of the rails 23 are housed in a housing 38 of the body 15 which is provided with a shaft 38a inserted into the tibial cutting guide support 32 ([Fig. 12]).

[0072] According to the invention, the tibial cutting guide block 3 is provided with a system for adjusting the tibial slope and the degree of tibial varus-valgus.

[0073] As illustrated in Figures 13 to 17, the tibial cutting guide support 32 comprises a first longitudinal fixed arm 27, at the end of which is disposed a first graduated element 25, typically a notched element, indicating different degrees of adjustment of the planned tibial slope.

[0074] A second fixed arm 28, having a longitudinal part followed by a vertical part, and belonging to the second part 15b of the tibial cutting guide block body 15, comprises at its lower end a second graduated element 26, typically a notched element, indicating different degrees of adjustment of the tibial varus-valgus.

[0075] The adjustment of the tibial slope and the degree of tibial varus-valgus is carried out by means of two movable arms 29, 30 of the cutting guide support 32 and which are articulated in rotation relative to the second support 15b.

[0076] The cutting guide support 32 comprises two parts, namely a first part 32a which directly supports the cutting guide 16 and a second part 32b around which the first part 32a is rotatably mounted, along a transverse axis B (Figures 12, 18 and 19). The second part 32b is rotatably mounted around the shaft 38a of the second part 15b, along a longitudinal axis C.

[0077] A first movable arm 29 allows the adjustment of the tibial slope. The first movable arm 29 is movable in rotation, around the axis B, relative to the second part 32b of the cutting guide support 32, the second part 32b being integral with the second part 15b ([Fig. 12]). Since the first movable arm 29 belongs to the cutting guide support 32, the rotation of the first movable arm 29 drives the first part 32a of the cutting guide support 32 and therefore the cutting guide 16 in rotation. The first part 32a of the cutting guide support 32 is thus mounted to rotate along the axis B around the second part 32b.

[0078] The first movable arm 29 has at one end a retractable adjustment knob 31 which, in the retracted position, is secured to the first graduated element 25 via a slider 31a in the form of an edge of the knob 31 which is locked in the notched zone of the first graduated element 25. The adjustment knob 31 is held in the retracted position using a spring. The first movable arm 29 is actuated in rotation by pulling on the retractable knob 31, so as to detach the retractable knob 31 from the first graduated element 25. When the knob 31 is thus in the deployed position, the rotational actuation of the knob 31 drives in rotation the first part 32a of the cutting guide support 32 and therefore the cutting guide 16.The desired tibial slope is obtained by positioning the cursor 31a opposite the predetermined degree of tibial slope and then releasing the button 31 which returns to its retracted position in which the first movable arm 29 is secured to the first fixed arm 27. The rotational movement of the first movable arm 29 is limited by a centering pin 22 of the first movable arm 29 which moves between two ends of a slot 24 of the first fixed stocking 27.

[0079] A second movable arm 30 allows the degree of tibial varus-valgus to be adjusted. The second movable arm 30 is movable in rotation relative to the second part 15b around the axis C. The rotation of the second movable arm 30 drives the second part 32b of the cutting guide support 32 in rotation around the shaft 38a of the second part 15b and therefore the cutting guide 16. The cutting guide support 32 is thus mounted for rotation around the second part 15b.

[0080] The second movable arm 30 has at its lower end a retractable adjustment knob 35 which, in the retracted position, is integral with the second graduated element. 26 via a slider 35a in the form of an edge of the button 35 which is locked in the notched area of ​​the second graduated element 26. The adjustment button 35 is held in the retracted position using a spring. The second movable arm 30 is actuated in rotation by pulling on the retractable button 35, so as to detach the retractable button 35 from the second graduated element 26. When the button 35 is thus in the deployed position, the rotational actuation of the button 35 drives in rotation the second part 32b of the cutting guide support 32 and consequently the first part 32a which is integral in rotation with the second part 32b during a rotation of the second part 32b around the axis C. The cutting guide 16 is therefore also driven in rotation.The desired degree of tibial varus-valgus is obtained by positioning the cursor 35a opposite the predetermined degree of varus-valgus and then releasing the button 35 which returns to its retracted position in which the second movable arm 30 is secured to the second fixed arm 28. The rotational movement of the second movable arm 30 is limited by a centering pin 36 of the second movable arm 30 which moves between two ends of a slot 37 of the second fixed stocking 28.

[0081] When it is actuated in rotation around the axis B, the first movable arm 29, which is not integral in rotation with the part 32b and therefore with the second fixed arm 27 and the second movable arm 30, does not drive in rotation the second fixed arm 27 and the second movable arm 30. As for the second movable arm 30, it is integral with the first fixed arm 27 during a rotation of the second movable arm around the axis C. When it is driven in rotation around the axis C, the second movable arm 30 therefore drives in rotation the first fixed arm 27 and therefore the first movable arm 29 which is integral with the first fixed arm 27.

[0082] To summarize, an actuation of the first movable arm 29 only drives the first part 32a in rotation, and not the second part 32b. An actuation of the second movable arm 30 drives both the first part 32a and the second part 32b in rotation. Regardless of the rotation, the first part 15a and the second part 15b of the tibial cutting guide block body 15 remain fixed during the rotation. Regardless of the rotation, the securing of the cutting guide support 32 to the tibial cutting guide block body 15 is achieved by locking the second movable arm 30 of the second part 32b on the fixed arm 28 of the second part 15b.

[0083] For a given degree of tibial varus-valgus, it is thus possible to adjust the tibial slope without modifying the degree of tibial varus-valgus, and vice versa.

Claims

Claims

1. Device (1) for assisting in positioning a tibial cutting guide, comprising an alignment post (4) extending along a main axis of the device (1), and on which a tibial cutting guide block (3), provided with a tibial cutting guide (16) mounted on a tibial cutting guide support (32), is movable in translation along the main axis, the device (1) being characterized in that the tibial cutting block (3) is provided with a system for adjusting the tibial slope of the tibial cutting guide (16) and / or a system for adjusting the degree of tibial varus-valgus of the tibial cutting guide (16).

2. Device (1) according to claim 1, characterized in that the tibial cutting guide block (3) is provided with a system for adjusting the tibial slope of the tibial cutting guide (16) and a system for adjusting the degree of tibial varus-valgus of the tibial cutting guide (16).

3. Device (1) according to claim 1 or 2, characterized in that the tibial cutting guide block (3) comprises a tibial cutting guide block body (15) extending generally in a plane orthogonal to the main axis of the device (1), said body (15) extending in a longitudinal direction, towards the tibia.

4. Device (1) according to claim 3, characterized in that the tibial slope adjustment system comprises a rotational mounting, with a transverse axis (B), of a first part (32a) of the tibial cutting guide support (32) around a second part (32b) of the tibial cutting guide support (32), the second part (32b) of the tibial cutting guide support (32) being, during this rotation with a transverse axis (B), integral with the tibial cutting guide block body (15).

5. Device (1) according to claim 4, characterized in that the system for adjusting the degree of tibial varus-valgus comprises a rotational mounting, with a longitudinal axis (C), of the second part (32b) of the tibial cutting guide support (32) around the tibial cutting guide block body (15), the second part (32b) of the tibial cutting guide support (32) being, during this rotation with a longitudinal axis (C), integral with the first part (32a) of the tibial cutting guide support (32).

6. Device (1) according to one of claims 3 to 5, characterized in that the tibial cutting guide block body (15) comprises a first part (15a) integral with the alignment post (4) and a second part (15b) movable longitudinally in translation relative to the first part (15a).

7. Device (1) according to claim 6, in conjunction with claim 4, characterized in that the first part (32a) of the tibial cutting guide support (32) comprises a first movable arm (29), integral with the second part (32b) of the tibial cutting guide support (32) in a locked position of the first movable arm (29) and not integral with the second part (32a) of the tibial cutting guide support (32) in an unlocked position of the first movable arm (29), the first movable arm (29) being, in its unlocked position, movable in rotation around the second part (32b) of the tibial cutting guide support (32).

8. Device (1) according to claim 7, characterized in that the first movable arm (29) is lockable, via an adjustment button (31) of the first movable arm (29), on a first graduated element (25) of the second part (32b) of the tibial cutting guide support (32).

9. Device (1) according to one of claims 6 to 8, in conjunction with claim 5, characterized in that the second part (32b) of the tibial cutting guide support (32) comprises a second movable arm (30), integral with the second part (15b) of the tibial cutting guide block body (15) in a locked position of the second movable arm (30) and not integral with the second part (15b) of the tibial cutting guide block body (15) in an unlocked position of the second movable arm (30), the second movable arm (30) being, in its unlocked position, movable in rotation around the second part (15b) of the tibial cutting guide block body (15).

10. Device (1) according to claim 9, characterized in that the second movable arm (30) is lockable, via an adjustment button (35) of the second movable arm (30), on a second graduated element (26) of the second part (15b) of the tibial cutting block body (15).

11. Device (1) according to one of claims 6 to 10, characterized in that the first part (15a) of the tibial cutting guide block body (15) comprises a wheel (17) having a thread (18) cooperating with a thread (11) of the alignment post (4) to form a screw-nut system.

12. Device (1) according to claim 11, characterized in that the wheel (17) comprises a button (19) the actuation of which is capable of separating the tapping (18) from the thread (11).

13. Device (1) according to one of claims 1 to 12, characterized in that the alignment post (4) is connected at its lower end to a pin (5) and is connected at its upper end to a fixing arm (6) with pins (7).

14. Device (1) according to one of claims 1 to 13, characterized in that the alignment post (4) comprises a distal rod (8) and a proximal tube (9) inside which the distal rod (8) can slide.

15. Device (1) according to claim 14, in conjunction with claim 11, characterized in that the thread (11) belongs to the proximal tube (9).

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