JP2990521B2 - Artificial joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a knee joint that has been highly deformed due to rheumatism, osteoarthritis, or the like, or a knee joint function that has been destroyed due to a traffic accident, disaster, tumor, or the like. The present invention relates to an artificial joint used to restore the original normal function.

[Prior art and its problems] In a conventional artificial joint, in a knee joint, the distal end side of the femur and the proximal side of the tibia are cut into bones so as to conform to the shape of each member, and reaming is performed. The member is attached to the removed portion by a method such as press-fitting, screw fixing, or using bone cement.

In Figure 5, shows the femoral component D constituting the knee joint, the shape of the distal end of the osteotomy femur F in order to mount the femoral component D, also FIG. 6 is the tibia T FIG. 8 is a view for explaining a method for attaching the tibial member G to the proximal end of the joint, and it is important in the osteotomy performed when attaching these members that the joint originally possessed by the knee joint is important. This is how to cut the bone into a precise shape so that each member can be installed in a state where the function can be reproduced.

In other words, this means that if accurate osteotomy corresponding to the shape of each member is not performed, the muscle around the knee joint, the tension or loosening of the ligaments etc. will limit the range of motion,
Alternatively, the members may be loosened, displaced, settled, or the like in a long-term use, and the original joint cannot be reproduced. As a result, each member needs to be removed and replaced again. When another accurate osteotomy is used as an important reason that it cannot be installed accurately due to incomplete osteotomy, the non-uniform load is applied to each member itself, and originally, Excessive stress is applied even to a portion where no load is applied. This causes deformation, wear, breakage, and the like of each member, and also leads to bone resorption around the attached member. as a result,
This will shorten the life of the artificial joint.

For the above reasons, it is obvious that it is important to perform accurate osteotomy, and various osteotomy jigs have been devised for performing accurate osteotomy.
Actually, it is difficult to set the jig to cut the deformed bone, and the jig may be shifted during the operation.
I had to rely on experience and intuition.

In the case of severe deformation, it is very difficult to perform an accurate osteotomy completely corresponding to the shape of the member.

In order to solve these inconveniences, a method of preparing a large number of members having different sizes and thicknesses, and selecting a member suitable for the amount of osteotomy from among them during the operation was used. . However, this requires an increase in the amount of preparation and handling of the members, and the corresponding amount of osteotomy jigs becomes enormous, so it is actually difficult to mount the optimum members in a short time. Was.

[Means for Solving the Problems] In order to solve the above problems, a plate-shaped tibial member having a sliding portion on its upper surface that forms an articulation surface with a femoral member, and a lower surface of the tibial member are formed. A stem part inserted into the medullary cavity, a groove, a groove on the lower surface of the tibia member or the outer periphery of the stem portion, provided with an attachment portion such as a groove,
The length and thickness of the tibial member are adjusted by inserting a substantially U-shaped adjustment plate for adjusting the insertion amount to be inserted into the medullary cavity of the stem portion into the attachment portion, and the bone cut surface is adjusted. To eliminate the gap created between them and to correct the shape of the tibial component by prosthesis only when the deformation is severe or the amount of bone defect is large, etc. Features.

[Operation] 1. The thickness and height of the tibial member can be adjusted, and the joint member can be selected according to the osteotomy shape from the conventional osteotomy corresponding to the tibial member.

2.Elimination of the gap between the tibial member and the bone cut surface enables accurate and stronger attachment of the tibial member, and prevents long-term use, preventing loosening, displacement, sinking, etc.
Stable joint function can be reproduced.

3. Even if there is a defect such as a tumor, the portion can be corrected with a tibial member to a prosthetic shape, thereby minimizing the amount of osteotomy and leaving normal bone as much as possible.

4. Instead of preparing many tibial members of different shapes and sizes as in the past, it is only necessary to prepare several types of plates for thickness adjustment, and disinfect and procure surgical instruments before surgery. Becomes easier.

[Example] Hereinafter, the present invention will be described with an example with reference to the drawings.

FIG. 1 is a perspective view of an artificial joint (artificial knee joint) according to the present invention. This artificial joint is formed on a plate-shaped tibial member 1 and formed on the lower surface of the tibial member 1, and is inserted into the tibial cavity. And a stem portion 3 to be inserted. Further, the tibial member 1 is a metal or ceramic femoral member (not shown).
And a sliding portion 2 forming a sliding surface between the sliding portion 2 and the sliding portion 2.

The sliding surface of the sliding portion 2 is made of polyethylene, high-density polyethylene, or the like for sliding with the femoral member, while the stem portion 3 is made of metal or ceramic to reinforce the sliding portion 2. And so on.

Further, the stem portion 3 is provided with one or several U-shaped grooves 4 in the circumferential, longitudinal and lateral directions, whereas the adjusting plate 5 for adjusting the thickness is provided on the stem 3. A notch 6 corresponding to the groove 4 is provided. And
It is possible to arbitrarily adjust the thickness of the tibial member 1 by inserting one or several plates 5 corresponding to the thickness of the gap with the bone in the direction of the arrow in the figure. As a result, the tension of the muscular ligament around the knee joint can be adjusted to the most suitable state, a larger joint movable range can be secured, and a more stable postoperative mounting state can be provided. The shape of the adjustment plate 5 may be the shape of the sliding portion 2 or the shape adapted to the cut surface of the tibial bone.
It is made of a metal material such as a titanium alloy or a ceramic. If there is a bone defect near the central condyle of the tibia, a plate corresponding to the defect shape may be inserted.

FIG. 2 shows another embodiment, in which an adjusting plate 5 having various thicknesses is inserted into a groove 4a formed around a lower surface 2a provided on the tibial member 1 as a mounting structure of the adjusting plate 5. A notch 6 having a slope 5a adapted to the groove 4a is provided. The groove 4a and the slope 5a may be formed on each other on the mating member.
4a may be formed on the outer peripheral portion of the side surface of the sliding portion 2. Further, in the above embodiment, the adjustment plate 5 is fitted from the front-back direction of the tibial member 1, but the invention is not limited to this.
As shown in the drawing, a groove 4a may be formed on the side and the adjustment plate 5 'may be inserted from the side.

It should be noted that the tibia T whose joint sliding surface has been deformed due to varus deformation as shown in FIG. 4 is generally cut by a straight line K ′. In order to minimize the cutting amount, bone cutting is performed along a straight line K in the figure. In this case, since the concave portion due to the bone defect A is generated at the end, the tibial member 1 as shown in FIG. 1 is placed in an unstable state. As shown in FIG. 3 above, a prosthetic shape is used in which the sliding portion 2 of the tibial member 1 is provided with a groove 4a in the left-right direction, so that only the left side matches the shape of the bone defect A. Plate 5 'may be attached. In this way, it is not necessary to perform the osteotomy performed on the osteotomy surface K ', which increases the amount of osteotomy, and it is possible to leave a little more normal bone.

In the above embodiment, an example in which only one flat adjustment plate is inserted into the member has been described, but the invention is not limited thereto, and a plurality of adjustment plates may be used in combination, and the thickness is not uniform, for example. It is also possible to use an adjustment plate having a partially thinner thickness on one side and a thicker thickness on the other side.

[Effect of the Invention] As described above, a groove or a grooved attachment portion is provided in the tibial member or stem portion of the artificial joint, and the adjustment plate is attached to this attachment portion, so that a gap formed between the tibial member and the stem surface. To provide an artificial joint that can also eliminate bone loss and prosthesis, and furthermore, it is possible to arbitrarily adjust the thickness, height, neck length, etc. of the tibial member, and at the same time, only a small amount of bone cutting is necessary, In artificial joints for the purpose of reproducing the original function of the knee joint, there is a great deal that will become better and contribute to human welfare.

[Brief description of the drawings]

1, 2 and 3 relate to an embodiment of the present invention, and are views for explaining a structure for mounting an adjustment plate to each tibial member, and FIG. 4 shows the artificial joint of the present invention on a deformed tibia. It is a figure for demonstrating the bone cut surface in the case of applying. FIG. 5 is a view for explaining a method of mounting the tibial member of the conventional artificial joint to the cut femur, and FIG. 6 is a diagram illustrating mounting the tibial member of the conventional artificial joint to the cut tibia. FIG. 4 is a diagram for explaining a method of performing the operation. 1: Tibial member, 2: Sliding part 3: Stem part, 4: Groove, 5: Adjustment plate

Claims (1)

(57) [Claims] 1. A plate-shaped tibial member having a sliding portion forming an articular surface with a femoral member on an upper surface, and a stem portion formed on a lower surface of the tibial member and inserted into a medullary cavity. An artificial joint, which is provided with a mounting portion such as a groove or a groove on the lower surface of the tibia member or the outer periphery of the stem portion, and the mounting portion is configured to adjust an insertion amount inserted into the medullary cavity of the stem portion. U
An artificial joint characterized by having an adjustment plate shaped like a character inserted therein.