Ball joint manipulation clamp

Abstract

The invention relates to a manipulator (1) for a ball joint (91), comprising: - a gripping handle (2); - two movable jaws (31, 32) relative to each other so as to modify the distance between these two jaws, the movable jaws being fixed to the gripping handle; - a control device (4) for the distance between the two jaws (31, 32); - optical reflectors (5) fixed to the gripping handle. Figure to be published with the abbreviation: Fig. 7

Description

Title of the invention: Ball joint manipulation clamp

[0001] The invention relates to orthopedic surgical operations, and in particular to robotic or navigated surgical operations for prosthetic knee surgery with patellar resurfacing.

[0002] The patella articulates with the femoral trochlea, forming the patellofemoral compartment. The patellofemoral compartment is the third joint of the knee, located anterior to the knee. Patellar stability is ensured by two tendons, one superior and one inferior, and the two patellar retinacula. It is this complex combination of bone morphology, muscles, cartilage, and tendons that can lead to the development of pathologies, particularly wear and tear such as osteoarthritis.

[0003] The kneecap is subjected to extremely high mechanical stresses; its role is essential in extension and flexion, as well as in squatting and jumping movements. The kneecap also acts as a shock absorber. Wear of the patellar cartilage is irreversible, and a misalignment or dislocation does not heal spontaneously. Movements become painful, some even impossible, and walking becomes increasingly difficult.

[0004] Many conditions can lead to premature wear of the knee cartilage, resulting in pain, limping, joint stiffness, and limitations in the patient's activities. In some cases, the patient may require a total knee replacement. This operation requires very precise cuts and bone preparation. It is a complex procedure that, in some cases, does not provide complete patient satisfaction.

[0005] Implanting a prosthesis requires highly precise prior machining of the bone intended to receive the prosthesis. Certain surgical procedures allow for even greater precision in making the bone cuts. These surgical procedures utilize robots or infrared navigation systems. These procedures employ infrared sensors fixed in the femur and tibia for the duration of the surgical procedure, particularly during total knee replacement. These sensors allow the robot / navigation system to position the cutting tools in real time and with precision to best adapt to the geometry of the prosthetic components.

[0006] In addition to the perfect fit between the bone and the implant, the surgeon must take into account ligamentous tension as well as patellar movement. Every error, even minor, can lead to an imperfect result. Therefore, there is a need to reduce the risk of performing a procedure that does not fully satisfy the patient.

[0007] The invention aims to resolve one or more of these drawbacks. The invention thus relates to a ball joint manipulation clamp, comprising: -a gripping handle; -two jaws movable relative to each other so as to modify the spacing between these two jaws, the movable jaws being attached to the gripping handle; -a device for controlling the gap between the two jaws; -optical reflectors attached to the gripping handle.

[0008] The invention also relates to the following variants. Those skilled in the art will understand that each of the features of the following variants can be combined independently with the above features, without thereby constituting an intermediate generalization.

[0009] According to one variant, said gripping handle comprises a housing relative to which said movable jaws are mounted pivotally or sliding, said reflectors being mounted projecting relative to said housing.

[0010] According to yet another variant, said reflectors comprise an armature and at least one reflecting element fixed to the armature.

[0011] According to another variant, the frame is selectively removable from the handle of grasping.

[0012] According to yet another variant, the frame has a threaded end screwed into the gripping handle.

[0013] According to one variant, the gripping handle has a first axial end having distinct fixing locations allowing the removable fixing of a frame in different orientations relative to the gripping handle.

[0014] According to yet another variant, the gripping handle has a second axial end having a fixing location allowing the removable attachment of a frame.

[0015] According to another variant, the device for controlling the gap between the two jaws comprises a drive wheel driving said jaws by means of a worm gear, the wheel being mounted pivotally relative to said gripping handle and its pivoting modifying the gap between said jaws.

[0016] According to yet another variant, the gap control device includes a gap locking mechanism between the two jaws.

[0017] According to one variant, the two movable jaws can be separated at least over a range of 30 to 50 mm.

[0018] According to another variant, the two jaws each comprise two protruding elements forming an acute angle at their end.

[0019] According to yet another variant, the ends of the protruding elements of the jaws are in a plane, the manipulating clamp providing a first free space opposite the jaws for the passage of tendons on a first side of this plane, and providing a second free space opposite the jaws for the passage of tools on a second side of this plane opposite to the first.

[0020] According to yet another variant, the jaws have an adjustable spacing along a first axis, one of said jaws having two hooks separated from each other along a second axis perpendicular to the first, so as to allow access along the first axis to a space between said jaws.

[0021] Other features and advantages of the invention will become clear from the following description, which is by way of example and not limitation, with reference to the accompanying drawings, in which:

[0022] [Fig-1] is a perspective view of an example of a handling clamp according to a first example of an embodiment of the invention;

[0023] [Fig.2] is a perspective view of the manipulator clamp of [Fig.1];

[0024] [Fig.3] is an enlarged view at the level of the jaws of the gripper of [Fig.1];

[0025] [Fig.4] is a perspective view of the clamp of [Fig.1] illustrating a mechanism internal jaw control;

[0026] [Fig.5] is an enlarged perspective view of the mechanism of the [Fig.4];

[0027] [Fig.6] is a front view of an example of an optical reflector system;

[0028] [Fig.7] is a side cross-sectional view of the clamp of the [Fig.1] carrying the system of the [Fig.6];

[0029] [Fig.8] is an enlarged view of the jaws gripping a ball joint;

[0030] [Fig.9] is a perspective view of an example of a manipulation gripper according to a second example of an embodiment of the invention;

[0031] [Fig. 10] is a perspective view of the manipulator clamp of [Fig.9];

[0032] [Fig. 11] is a top view of the gripper of [Fig.9] at the jaw level;

[0033] [Fig. 12] is a top view of the jaws of the gripper of the [Fig. 9] gripping a kneecap.

[0034] Figures 1 and 2 are perspective views of an example of a manipulator gripper 1 according to a first embodiment of the invention. The gripper 1 is designed to grip a ball joint, allowing its manipulation by a practitioner, as well as its use for controlling a tool-holding robot. The gripper 1 includes a gripping handle 2. The gripper 1 is equipped with two movable jaws 31 and 32 relative to each other so as to modify the gap between these two jaws. The gap thus allows a ball joint to initially pass through. between jaws 31 and 32, then clamp the latter to fix the clamp 1 to this ball joint. Jaws 31 and 32 can advantageously be spaced within a range of 30 to 50 mm to allow a ball joint to be selectively passed through or clamped between them. This spacing can advantageously be reduced to 20 mm, or even to 15 mm. It can also be increased to 70 mm.

[0035] The movable jaws 31 and 32 are fixed to the gripping handle 2. A movement exerted by the practitioner on the gripping handle 2 thus allows the position of the patella held between the jaws 31 and 32 to be modified. The clamp 1 further includes a control device 4 for the spacing between the two jaws 31 and 32. The clamp 1 also includes optical reflectors fixed to the gripping handle 2. An example of optical reflectors will be described in detail later. The optical reflectors can, in particular, be designed to reflect infrared radiation. The optical reflectors are used, in a manner known per se, to be identified by sensors in order to determine their position in space.

[0036] Thus, the use of a clamp 1 according to the invention makes it possible to perfectly locate the clamp 1 in space relative to a patella, on which a three-dimensional scan or bone shape scan is performed. The position of the clamp 1 and the patella are then perfectly identified for the control of a tool-holding robot (not shown). The tool-holding robot can then constrain the movements of the tools relative to the patella and the clamp 1 in real time, in order to avoid surgical incidents. The tools are typically saws or milling cutters used to shape a face of a patella to which a prosthesis is to be fixed.

[0037] Figure 3 is an enlarged view of the jaws 31 and 32 of the gripper 1. As illustrated, the gripping handle 2 has a housing 6 relative to which the movable jaws 31 and 32 are mounted to pivot or slide. In the illustrated example, the movable jaws 31 and 32 are mounted to pivot relative to the housing 6. The housing 6 here serves to protect parts of the gap control device 4. The housing 6 can also serve to hold optical reflectors. As can be seen in particular from Figure 7, the optical reflectors 5 are mounted projecting from the housing 6.

[0038] Figures 4 and 5 provide a clearer visualization of an example of a gap control device 4, in the absence of the housing 6. The device 4 here comprises a knurled wheel 41 pivotally mounted relative to the handle 2 around a longitudinal axis. The knurled wheel 41 drives a shaft mounted to rotate relative to the handle 2. A worm gear 42 drives the jaws 31 and 32 in rotation around longitudinal axes, in order to adjust their gap along a transverse axis. More precisely, the gear 42 comprises helical teeth formed at a end of the shaft. The helical gears mesh with two spur gears, mounted to pivot about transverse axes relative to the housing 6. Each of these spur gears includes a bevel gear protrusion along its axis. These bevel gears are coupled with bevel gears fixed to the jaws 31 and 32.

[0039] Thus, by turning the knob 41, a simultaneous rotation of the same amplitude is obtained for the jaws 31 and 32. Furthermore, a worm gear drive allows the position of the jaws to be automatically locked at the end of the manipulation of the knob 41.

[0040] The wheel 41 is advantageously removable when combined with a worm gear drive, since such a mechanism is automatically locked in position.

[0041] The device 4 may also have another design. Such a device 4 may be equipped with a locking mechanism for the gap between the jaws 31 and 32, so that the clamp 1 remains firmly attached to a ball joint 91 after it has been clamped.

[0042] Fig. 8 is an enlarged view of the jaws 31 and 32 clamping a ball joint 91. A milling cutter 92 positioned in a workspace 94 for tools has been schematically illustrated.

[0043] As referenced in [Fig. 5], the jaws 31 and 32 each comprise two projecting elements forming an acute angle at their ends, in order to grip the ball joint securely. Thus, the jaw 31 has two such projecting elements 311 and 312. The projecting elements will advantageously be moved by the device 4 so as to remain in the same plane.

[0044] If a plane is defined passing through the projecting elements of the jaws 31 and 32, the manipulator clamp 1 provides a first free space opposite the jaws 31 and 32 for the passage of tendons on one side of this plane. This free space is therefore outside the clamp 1. The manipulator clamp also provides a second free space 94 opposite the jaws 31 and 32 for the passage of tools on a second side of this plane. This free space 94 is therefore inside the clamp 1.

[0045] Fig. 6 is a front view of an example of an optical reflector system 5. Fig. 7 is a side section view of the clamp 1 carrying this system.

[0046] In this example, the reflectors 5 are arranged on the same support. Alternatively, the reflectors 5 can be fixed independently at different locations on the clamp 1.

[0047] The reflectors 5 typically comprise a frame 50 and at least one reflector element 52 attached to the frame 50. In the illustrated example, 4 reflector elements 52 are attached to a frame 55 of the frame 50.

[0048] Advantageously, the frame 50 is selectively removable from the grip handle 2. Thus, different reflectors 5 can be attached to the handle 2 and the handle 2 can also be more compact for storage.

[0049] For this purpose, the frame 50 has a threaded end 53 intended to be screwed into the gripping handle 2. In the illustrated example, the frame 50 is fixed in the gripping handle by several threaded ends 53. The threaded ends 53 are typically provided on rods 51, driven in rotation relative to the frame 50 by means of wheels 54.

[0050] Advantageously, the gripping handle 2 has a first axial end 23 having distinct mounting locations 61 allowing the removable attachment of a frame 50 in different orientations relative to the handle 2. Thus, in the illustrated example, mounting locations 61 are arranged on the different faces of the housing 6, which has a parallelepiped shape. Each face has four mounting locations. The mounting locations 61 correspond to threaded bores.

[0051] The gripping handle 2 advantageously comprises a second axial end 24. This axial end 24 also comprises a fixing location allowing the removable attachment of a frame 50. These locations can also be arranged on different faces of the axial end 24.

[0052] Figures 9 to 11 are different views of an example of a handling clamp 1 according to a second example of an embodiment of the invention.

[0053] The clamp 1 has jaws 31 and 32 with an adjustable spacing along the longitudinal axis. One of these jaws has two hooks 33 and 34 separated from each other along the transverse axis, so as to allow access along the first axis to a space between the jaws. The other jaw 32 also has two hooks 35 and 36 separated from each other along the transverse axis.

[0054] The wheel 41 here drives gears that slide the hooks 33 to 36 along the longitudinal axis. The rotation causes the jaws 31 and 32 to slide in opposite directions simultaneously and with the same amplitude.

[0055] Fig. 12 is a top view of the jaws 31 and 32 of the clamp 1 gripping a ball joint 91. As illustrated, the design of these jaws 31 and 32 allows the passage of a saw 93 or a milling cutter 92.

[0056] The invention also relates to a method for controlling a tool-carrying robot, this method comprising, for example, the steps of: -filming a space in which a manipulation clamp 1 is positioned; -by digital processing, identify the position of the optical reflectors 5 in the filmed space, and determine the position of the manipulation clamp 1 from the position of the optical reflectors 5 identified; -to restrict the movement of a robot tool relative to the handling gripper according to the position determined for the handling gripper 1.

[0057] According to another aspect of the invention, the method for controlling the tool-carrying robot comprises the steps of: -filming a space in which a manipulation clamp 1 is positioned; -by digital processing, identify the position of the optical reflectors 5 in the filmed space, and determine the position of the manipulation clamp 1 from the position of the identified optical reflectors 5, determine the shape and position of the filmed ball joint; -to restrict the movement of a robot tool relative to the ball joint according to the determined shape and position of the ball joint.

[0058] The method is thus used to restrict the movement of the robot's tools by the practitioner, in order to avoid any handling errors.

[0059] In the preoperative phase, the scan requires additional work to dimension the patella. This leads to the preoperative planning of the tibial implant, the femoral implant, and the patellar implant.

[0060] Pre-operative planning allows for the positioning of the femoral implant, the patellar implant and a simulation of the patellar race.

[0061] A preliminary operation is carried out in the usual way with positioning of the tibial and femoral implant.

[0062] Then the patella is exposed with partial or complete eversion, depending on the surgeon's preference. Typically, such a robot is activated to perform the bone preparation of the patellar surface. Two techniques can be used for this:

[0063] -either a bone cut is made with an oscillating saw, followed by milling to create the implant positioning pads;

[0064] -either we carry out a milling of the impression of the implant with the creation of the pads during two successive steps.

[0065] The surface is then cleaned of milling residue, and the trial patellar implant can be positioned. Clamp 1 is then removed. The surgeon can then check the patellar travel before proceeding with the placement of the definitive implants.

Claims

Demands

1. A manipulator (1) of a ball joint (91), characterized in that it comprises: - a gripping handle (2); - two movable jaws (31, 32) relative to each other so as to modify the spacing between these two jaws, the movable jaws being integral with the gripping handle; - a control device (4) for the spacing between the two jaws (31, 32); - optical reflectors (5) integral with the gripping handle.

2. Handling clamp according to claim 1, in which said gripping handle (2) comprises a housing (6) relative to which said movable jaws (31, 32) are mounted pivotally or sliding, said reflectors (5) being mounted projecting relative to said housing (6).

3. Handling clamp according to claim 2, wherein said reflectors (5) comprise a frame (50) and at least one reflector element (52) fixed to the frame.

4. Handling clamp according to claim 3, wherein the frame (50) is selectively removable from the gripping handle (2).

5. Handling clamp according to claim 4, wherein the frame (50) has a threaded end (53) screwed into the gripping handle (2).

6. Handling clamp according to claim 4 or 5, wherein the gripping handle (2) has a first axial end (23) having distinct fixing locations allowing the removable fixing of a frame (50) in different orientations relative to the gripping handle.

7. Handling clamp according to claim 6, in which the gripping handle (2) has a second axial end (24) having a fixing location allowing the removable fixing of a frame (50).

8. A handling gripper according to any one of the preceding claims, wherein the control device (4) for the gap between the two jaws (31, 32) comprises a drive wheel (41) driving said jaws via of a worm gear (42), the wheel being mounted pivoting relative to said gripping handle and its pivoting modifying the spacing between said jaws (31, 32).

9. Handling clamp according to any one of the preceding claims, wherein the gap control device (4) includes a gap locking mechanism between the two jaws (31, 32).

10. A handling clamp according to any one of the preceding claims, wherein the two movable jaws (31, 32) can be at least spread apart over a range of 30 to 50 mm.

11. A handling clamp according to any one of the preceding claims, wherein the two jaws each comprise two protruding elements forming an acute angle at their end.

12. A manipulator according to claim 11, wherein the ends of the protruding elements of the jaws are in a plane, the manipulator providing a first free space opposite the jaws for the passage of tendons on a first side of this plane, and providing a second free space opposite the jaws for the passage of tools on a second side of this plane opposite the first.

13. A handling clamp according to any one of the preceding claims, wherein the jaws have an adjustable gap about a first axis, one of said jaws having two hooks separated from each other about a second axis perpendicular to the first, so as to allow access along the first axis to a space between said jaws.

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