FR2787012A1 - KNEE ENDOPROSTHESIS - Google Patents

Abstract

Knee endoprosthesis making it possible to switch from a "bi" or "tricompartmental" endoprosthesis of the knee to a total knee endoprosthesis without having to remove the tibial part of the endoprosthesis characterized in that it comprises a tibial part having a machined C2 cylinder either in the form of a truncated cone or of a cylinder in its upper part and then threaded TrC2 and an oblique hole Tcl which ends in the hole TrC2. In the event that the surgeon decides to put a "tricompartmental" endoprosthesis, the latter inserts the tibial plateau thereof after having chosen the one which allows a slight rotation around the hole TrC2 or the fixed one. The surgeon can then put on a total endoprosthesis without removing the tibial part. He will have to remove the tibial plateau, replace it with that of the total endoprosthesis and install in the hole TrC2 the pivot T and put the key in the hole Tcl.

Description

Title: endoprosthesis for the knee joint.

  The present invention relates to a stent for the joint.

knee lation.

  There are two main types of knee endoprostheses: - the "bi" and "tricompartimenta-" knee endoprosthesis

  "used when the surgeon keeps the ligaments.

  - the total knee endoprosthesis used when the

ligaments are not preserved.

  The first consists of three main parts: - the femoral part has two shells forming the convexly curved condyles with,

  in some cases, at its upper part a rod.

  - the polyethylene tibial plateau

  on which slide the femoral condyles.

  - the part forming the tibia on which-

  the tibial plateau is fixed at its lower end

have a stem.

  The second consists of three main and two secondary parts: main parts: - the part forming the femur or femoral insert has two shells forming the curved condyles of

  convex and, at its upper part, a rod.

  - the tibial plate in polyethylene - the part forming the tibia or insert

  tibial which has at its lower part a keel.

  The hole in the horizontal axis of the femoral part receives

  the vertical cylindrical part which serves as a connection between

femoral tie and tibial part.

- secondary parts:

- the patellar plateau.

- the make-up shims.

  The object of the present invention is to make it possible to pass from a three-compartment knee endoprosthesis to a total knee endoprosthesis without the surgeon being forgotten.

ge to change the tibial part.

  - 2 - This object is resolved, according to the present invention, by the fact that:

  - the tibial part present at its lower part

  lower two cylinders Cl and C2 .: - Cl: this cylinder is drilled at its lower part and machined over part of its height in the form of a truncated cone then tapped or truncated cone only;

  in this case the tibial part is pierced opposite this last

  deny to allow the passage of a screw which screws into the upper end of the keel. In this hole will be screwed

  a keel whose length will have been chosen by the doctor.

  - C2: this cylinder, at its upper part

  upper, has a machined hole in the shape of a truncated cone or in the shape of a cylinder at the top and then tapped, located posteriorly to the axis of the keel and is centered relative to the lateral edges of the tibial part

  is eccentric. An oblique cylindrical hole gives into this hole.

  - the tibial polyethylene plate of the endo-

  three-compartment prosthesis has at its lower part an extra thickness which will fit into the bean-shaped throat located at the upper part of the tibial part; this part may have a narrower width than the groove to allow rotation. It also has a non-frustoconical or cylindrical shape, reinforced or not by a metal piece, which enters the hole in the tibial part. In

  the ventral part, the tibial plateau has a hole which

  çoit a screw which is fixed on the tibial part; he can have

  a bean shape so as to allow a slight rotation

one of the tibial plateau.

  - the vertical pivot of the total stent consists of: - an upper part which penetrates into the hole located in the nut of the femoral part, and the top of which is frustoconical so as to facilitate the insertion of the

pivot in the nut.

  - a lower part is truncated -

  be cylindrical at first then tapped. There is a -3-

  peripheral groove opposite the oblique hole of the part

  biale. This groove receives the end of a key which prevents

che the extrusion of the pivot.

  The advantages of the present invention lie in particular

  relate to the fact that the surgeon can move from the three-compartment endoprosthesis to the total knee endoprosthesis without

  have to deposit the tibial part.

  In the following, an exemplary embodiment of the present invention is explained in more detail. Among the figures:

  - Figure 1 shows the tibial part seen from the side.

  - Figure 2 shows the tibial part in dorsal view.

  - Figure 3 shows the tibial part in ventral view.

  - Figure 4 shows the pivot of the total stent with the lower part, which fits into TrC2, cylindrical

and tapped.

  - Figure 5 shows a transverse view of the stent

total side view.

  - Figure 6 shows the tibial plateau of the total stent

seen from the side.

  - Figure 7 shows the tibial plateau of the total stent

seen ventrally.

  - Figure 8 shows the tibial plateau of the tri- stent

compartmental seen ventrally.

  - Figure 9 shows the total stent. seen dorsally.

  - Figure 10 shows the total stent viewed ventrally.

  - Figure 11 shows the three-compartment stent in ventral view. - Figure 12 shows the tibial part seen from below - Figure 13 shows the tibial part seen from above

  According to these figures, a geoprosthesis is described.

  nou whose tibial part - fig. 1 - present in its in-

  two cylinders - Cl - and - C2 -. The cylinder C1 is perforated - TrC1 - at its lower part and machined in the form of a truncated cone and then tapped in order to receive a keel of variable length. The cylinder C2 is perforated - TrC2 - at its upper part and machined is in the form of truncated cone or cylinder in its upper part and tapped either in the form of a truncated cone; these two cylinders can be joined in a single piece of elliptical shape. The tibial part presents at its upper part a groove - GPtTi - in the shape of hari

  cot and five vertical holes Trl, Tr2, Tr3, Tr4, Tr5 and an oblique hole Tcl - which ends in the cylinder hole - C2 -.

  This tibial part will be connected to the femoral part either of a three-compartment stent or of a total stent. In addition, the hole - TrC2 - of the cylinder - C2 - offset from the dorsal side with respect to the cylinder - Cl - and offset the teralement receives or the pivot - T -, connection between the tibial part and the femoral part of the stent total, or the part - Ttr - of the polyethylene plate, connection between the tibial part and the femoral part of the partial tricom endoprosthesis. The connection between the tibial part and the part

  femoral endoprosthesis is done by means of the pivot -

  T -, mobile, the lower part of which is introduced into the hole - TrC2 - of the cylinder - C2 -. This part is either conical or frustoconical or cylindrical at its upper part and then tapped. A circular groove - Gcl receives the end of a key inserted into the hole Tcl -. The cylindrical upper part enters the hole of the femoral nut

  To facilitate the maneuver the end is tapered.

  The polyethylene plate, connection between the tibia part and the femoral part of the three-compartment endoprosthesis has at its lower part a cylindrical part or conical section - TTrC2 - reinforced or not by a metal part

  which is positioned in the hole - TrC2 -. The part - TGPtTi -

  will be inserted into the throat - GPtTi - of the tibial part. This part is either of the same dimension or of an inferior dimension so as to allow rotation of a few degrees. It has in its ventral part a hole in which will be inserted a locking screw. In case the tray is provided

  to allow rotation the hole has an arc shape

key.

Claims (2)

  -1- Endoprosthesis for the knee joint characterized in that the tibial part - fig.1 - has at its lower part two cylinders C1 - and - C2 -. The cylinder C1 is perforated - TrCI - at its lower part and machined in the shape of a truncated cone and then tapped in order to receive a keel of variable length. The cylinder C2 is perforated - TrC2 - at its upper part and machined either in the form of a truncated cone or a cylinder in its upper part and tapped or in the form of a truncated cone. The tibial part has at its upper part a groove - GPtTi - bean-shaped and five holes   vertical Trl, Tr2 Tr3, Tr4 Tr5 and an oblique hole - Tcl -   which ends up in the hole in the cylinder -C2-.   -2- Endoprosthesis for the knee joint according to the res-   dication 1 characterized in that the hole - TrC2 - of the cylinder - C2 offset from the dorsal side with respect to the cylinder - Cl - and offset laterally receives the pivot - T -, connection between the tibial part and the femoral part of the total stent -3 - Endoprosthesis for the knee joint according to claim 1 characterized in that the hole - TrC2 - of the cylinder   C2 offset from the dorsal side with respect to the cylinder - Cl - and de-   laterally wedged receives the - Ttr - part of the polyethylene plate, connection between the tibial part and the femoral part   of the three-compartment stent.   -4- Endoprosthesis for the knee joint as claimed   cation 1 characterized in that the connection between the part ti-   bial and the femoral part of the total stent is made by means of a pivot - T - mobile whose lower part   eure is introduced into the hole - TrC2 - of the cylinder - C2 -.   This part is either frustoconical, or frustoconical or cylindrical at its upper part and then tapped. A groove - Gcl - circular receives the end of a key inserted in the hole - Tcl -. The cylindrical upper part enters the hole of the femoral nut. To facilitate the maneuver the extremity is frusto-conical.   - 5- Endoprosthesis for the knee joint according to the res-   dication 1 characterized in that the polyethylene plate - 6 bond between the tibial part and the femoral part   the three-compartment endoprosthesis present at its lower part   a cylindrical or frustoconical part - TTrC2 - reinforced   or not created by a metal piece - which is positioned in the hole TrC2 -. The part - TGPtTi - is inserted in the throat - GPtTi - of the tibial part. This part is either of the same dimension or of smaller dimension so as to allow   a few degrees rotation. He presents in his par-   ventral tie a hole in which a locking screw is inserted.