JPH05115499A - Artificial knee joint - Google Patents

Abstract

PURPOSE:To provide the artificial knee joint which satisfies the conditions of preventing excess expansion and preventing the pull-out of a thighbone side member and a tibia side member, engage both members with an allowance to obviate the generation of a failure and loosening by external force and stresses and is usable over a long period of time. CONSTITUTION:This artificial knee joint consists of the thighbone side member 10 and the tibia side member 20. A detaining projection 21b2 is formed at the front end of the bearing surface 21b of the tibia side member 20. A detaining piece 12 engaging with the detaining projection is formed in front of the curved projecting surface of the thighbone side member 10. Further, the front side of the bearing surface 21b is extended upward so as to prevent the pull-out of the thighbone side member 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial knee joint used in orthopedic treatment, and more particularly to an artificial knee joint capable of performing stable flexion operation and stop between the femoral side member and the tibial side member without causing dislocation. It is about the knee joint.

[0002]

2. Description of the Related Art In the treatment of knee joint disease, rheumatism, bone tumor, etc., a knee joint portion may be excised and an artificial knee joint may be attached instead. For example, a bone tumor is a disease in which the distal side of the femur 1 and the proximal side of the tibia 2 shown in FIG. 4 (a view in which the longitudinal section along the body side of the right leg is viewed from the rear side) are apt to generate tumors, It is necessary to excise the entire area between the one-dot chain lines C ₁ and C ₂ to prevent tumor metastasis to other areas. At this time, the anterior cruciate ligament 3a (back side of the paper), the posterior cruciate ligament 3b
(Front side of paper), medial collateral ligament 5a, lateral collateral ligament 5
Since all b is excised, all the motor function and the fixing function of the knee joint are lost.

Therefore, for such a patient, for example, FIG.
A hinge type artificial knee joint made of metal, ceramics, or a combination thereof as shown in (longitudinal cross-sectional view seen from the body side direction) and FIG. 6 (VI-VI line cross-sectional view of FIG. 5) is used. That is, the femoral side member 1A is joined to the femoral resection mark, and the tibial side member 2A is joined to the tibial resection mark, and the femoral side member 1A and the tibial side member 2A have the pin shaft 9 attached thereto. It is swingably supported via the shaft. The swing angle θ in the posterior direction with respect to the tibial vertical line is −5 to +110.
Free bending operation within a range of degrees is required. That is, the angle when a person sits is +110 degrees, while the angle of the hyperextended state when standing upright is -5 degrees, and it must be surely stopped in the hyperextended state when standing upright. However, the artificial knee joint shown in the example does not have a stopper function for this stop, and therefore it is necessary to use other orthosis or auxiliary equipment on the outside of the knee.

As another important function required for the artificial knee joint, it is required that the femoral member 1A and the tibial member 2A do not dislocate during flexion. In this respect, both members 1A and 2A shown in the examples of FIGS. 5 and 6 are pin-joined, and there is no fear of dislocation, but there were the following problems. That is, since both the members 1A and 2A have a structure in which they are pivotally supported by the pin shaft 9, there is no play allowance during the swinging motion, and the external force is not concentrated but acts entirely on the pin shaft 9. When the pin shaft 9 is cut off, or a large stress is generated on the stem boundary surface which is the joint between the artificial knee joint and the human body bone, slipping occurs at the boundary surface to cause a gap between the artificial knee joint and the human body bone. There was a problem that the entire artificial knee joint often had to be replaced within a short period of time due to loosening.

[0005]

Therefore, an object of the present invention is to complete an artificial knee joint that satisfies the following conditions (a) and (b) and is capable of stable rocking motion for a long period of time. is there. (B) When stopping the swing in the hyperextended state, it is possible to reliably control excessive swing flexion beyond the hyperextended state without the need for special auxiliary equipment such as external equipment. (B) It is possible to reliably prevent the femoral-side member and the tibial-side member from being dislocated and coming off during the swing bending operation and at the operating end stop portion thereof.

[0006]

The present invention, which has achieved the above object, comprises a femoral side member and a tibial side member, and the femoral side member is substantially saddle-shaped and is curved at least in the anterior-posterior direction on the left and right lower surfaces. An artificial knee joint in which curved convex surfaces are formed, and a pair of concave bearing surfaces for supporting the curved convex surfaces in contact with and supporting the curved convex surfaces are provided on the left and right upper surfaces of the tibial side member, at least the anterior side of the bearing surface. Are extended upward so as to prevent displacement of the femoral side member, and locking protrusions are formed on the upper ends of the extending portions, and the front end of each curved convex surface of the femoral side member is The gist of the present invention is that each is provided with a locking piece that engages with the locking projection.

[0007]

OPERATION AND EXAMPLES FIG. 1 shows a tibial member 2 according to the present invention.
0 embodiment, (A) is a plan view, (B) is a front view,
(C) is a left side view, (D) is a sectional view taken along line D-D of (B),
(E) is a sectional view taken along line EE of (A). Concave bearing surfaces 21a, 21b are formed on the left and right of the upper surface of the tibial member 20, and the bearing surfaces 21a, 21b are at least in the anterior-posterior direction [the lateral direction in the (D) figure] as shown in the (D) figure. It is formed by a concave curved surface. On the other hand the bearing surface 21b (21a) forms an extension 21b ₁ by long extended toward the front upper side of at least the member as shown in (D) figures, whereby coming off toward the front of the femoral member 10 Prevent. The upper end of the extension portion 21b ₁ has a tapered locking projection 21b ₂ (2
1a ₂ ) and a central convex portion 22 extending in the front-rear direction is formed between the left and right bearing surfaces 21a and 21b, and a central concave portion 13 of the femoral side member 10 to be described later is fitted into the central convex portion 22. The structure is such that the positional displacement of both members 10, 20 in the left-right direction is prevented.

On the other hand, FIG. 2 shows an embodiment of the femoral side member 10 which is paired with the tibial side member 20. FIG.
(B) is a front view, (C) is a left side view, and (D) is a bottom view. The femur side member 10 is formed in a substantially saddle shape, curved convex surfaces 11a and 11b are formed on the lower left and right sides thereof, and a central concave portion 13 is formed therebetween. The curved convex surface 11a,
The radius of curvature of 11b in the front-rear direction (10a-10b direction) may be either monocentric or polycentric. In the illustrated example, a polycentric combination of R28, R100, and R25 is illustrated. The radius of curvature of the curved convex surface is preferably the same as or substantially the same as the radius of curvature of the bearing surfaces 21a and 21b of the tibial member 20, and the difference in radius of curvature is recommended to be within 20 mm.

A hole 14 is formed in the upper part of the central concave portion 13, and a pin is inserted into the hole 14 and the pin is inserted into the bone marrow of the remaining femur to attach the member 10 to the femur. To join. Further, the front side 1 of the femoral side member 10
Locking pieces 12 and 12 are provided on the front ends of the curved convex surfaces 11a and 11b on the outer side of 0a, and a groove portion 15 is formed. The groove portion 15 is a locking projection 21b ₂ on the tibial member 20.
And the front side swing of both members 10 and 20 exceeding the overextended state is stopped.

FIGS. 3A to 3D are explanatory views showing the operating states of the femoral side member 10 and the tibial side member 20.
In (A), the locking protrusion 21b ₂ and the locking piece 12 engage with each other when the swing angle θ ₁ is stopped in the overextended state of −5 degrees, and the femur side member 10 is positioned relative to the tibial side member 20. Be sure to prevent further swinging forward.

[0011] (B), (C), (D) drawing (A) each swing angle of the femoral member 10 to the rear side than the state of Figure theta ₂ = 10
Time, theta ₃ = 98 °, shows a state in which displaced theta ₄ = 117 °, the upper bearing surface 21b curved convex surface 11b swings both members 10, 20 slidingly. At this time, the extension portion 21b ₁ located on the front side of the bearing surface 21b can securely receive the femoral side member 10 and prevent the femur side member 10 from slipping out to the front side.
No dislocation of 0,20 is caused.

Although the rear side 21b of the bearing surfaces 21a and 21b is shown to extend upward in the above-mentioned example, the present invention is not limited to this, and the rear side is formed in a face shape. Although the locking projections 21b ₂ and the locking pieces 12 are shown as a pair, respectively, they may be one as long as they engage with each other, and the shapes thereof are not shown. The members 1 are not limited to the examples, and are engaged with each other to form the two members 1.
A plate-like shape or a columnar shape may be used as long as it restricts excessive swinging from 0.

The femoral member 10 has the hole 14 as described above.
And the tibial member 20 is connected to the remaining femur via a pin, and the stem of the tibial member 20 is connected via a pedestal portion (not shown). The stem is inserted into the bone marrow of the remaining tibia to join the pedestal portion and the member 20. To do.

[0014]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the rocking of the femoral member and the tibial member to the anterior side is ensured by the engagement of the locking projection and the locking piece during overextension. In addition to being restricted, the extension of the bearing surface can prevent both members from coming out when bending.
Furthermore, since there is a play allowance in the engagement of both members, a large external force or stress is not partially concentrated to cause damage or loosening of the members, which enables long-term use.

[Brief description of drawings]

1 shows an embodiment of a tibial member of the present invention, (A) is a plan view, (B) is a front view, (C) is a left side view, and (D) is a line D-D of (B). Sectional drawing, (E) shows the EE sectional view taken on the line of (A).

FIG. 2 shows an embodiment of the femoral side member of the present invention, (A)
Is a plan view, (B) is a front view, (C) is a left side view, (D)
Shows a bottom view.

3 (A) to 3 (D) are explanatory views showing an operating state of the artificial knee joint of the present invention.

FIG. 4 is an explanatory diagram showing a knee joint.

FIG. 5 is a cross-sectional explanatory view showing an example of a conventional artificial knee joint.

6 is a cross-sectional view taken along the line VI-VI of FIG.

[Explanation of symbols]

10 Femur side member 11a, 11b Curved convex surface 13A, 13B Stopper surface 12 Locking piece 20 Tibial side member 21a, 21b Bearing surface 21b ₁ Extension part 21b ₂ Locking protrusion

Front page continuation (72) Inventor Kenji Doi 6-4-1 Suganodai, Suma-ku, Kobe (72) Inventor Yoshimasa Ito 6-56-104 Nishiochiai, Suma-ku, Kobe-shi (72) Takao Kawai Kobe-shi 4-21-2 Sousan-cho, Kita-ku

Claims (1)

[Claims] 1. A femoral side member and a tibial side member,
The femoral side member is substantially saddle-shaped, and curved convex surfaces curved in at least the front-back direction are formed on the left and right lower surfaces, and a pair of concave bearings that abut and support the curved convex surfaces on the left and right upper surfaces of the tibial side member. An artificial knee joint provided with a surface, wherein at least the front side of the bearing surface is extended upward so as to prevent displacement of the femoral side member, and the upper end of the extended portion is engaged with each other. An artificial knee joint characterized in that a stop projection is formed, and a locking piece that engages with the locking projection is provided at each front end of the curved convex surface of the femoral side member.