JPS6241733B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an artificial replacement of the scapula glenoid fossa used in total shoulder arthroplasty in humans, namely:
It concerns glenoid components manufactured by HDP.

In addition, HDP means high density polyethylene (high density polyethylete),
It is widely used as an artificial biomaterial in the medical field, especially in joint surgery (References:
Charnley J, Cupic Z. The nine and ten―
year results of the low-friction arthroplasty
of the hip.Clin Orthop 1973;95:9-25.
Griffith MJ, Seidenstein MK, Williams D,
Charnley J.Socket wear in Charnley low
friction arthroplasty of the hip.Clin Orthop
1978;137;37―47.Wroblewski BM.Direction
And Rate of Socket Wear In Charnley Low―
Friction Arthroplasty.J Bone Joint
Surg.1985;67-B;757-761.).

By the way, due to lesions such as rheumatoid arthritis, tumors, and osteoarthritis, the two elements that make up the shoulder joint, namely the glenoid fossa of the scapula and the head of the humerus, lose their function due to destruction of cartilage and bone. In the event of failure, our predecessors have long attempted to perform total shoulder arthroplasty to create a new shoulder joint. This time, we approached the shoulder joint from a functional anatomical and biomechanical perspective, and arrived at the invention described below.

Originally, the glenoid fossa of the scapula provides a place for the head of the humerus, which has an ellipsoidal convex surface, to perform rotational movements similar to a rolling ball, horizontal sliding movements, and rotational movements during shoulder joint movements. However, due to this complex movement style, the glenoid cavity of the human scapula has a complex shape, unlike the ball-and-socket relationship of the hip joint, where simple spherical movement occurs. It has developed and evolved.

By the way, we have already invented an artificial humeral head as described in Japanese Patent Application No. 58-219333.
The present invention is a companion to that technique and is used in total shoulder arthroplasty.

In the present invention, the sliding portion has a concave curved surface,
The outer ring of the sliding part is composed of a small circle a with a diameter of 2 rmm, a large circle b with a diameter of 2 rmm, whose centers are 1 mm apart from each other, and a convex curve c inscribed in these and a concave curve d circumscribed in them. r: 10 to 14 mm, thickness of the sliding part: 3 to 5 mm, preferably 4 mm, the stem part is composed of 3 to 5 crest-shaped wings, and each wing has a height of 2 to 4 wings. It has small protrusions of 1 to 3 mm, but it starts 3 to 7 mm inward from the outer ring edge of the sliding part and converges in a curve at a point 15 to 20 mm behind the sliding surface, and the blade thickness is 2. ~10mm.

By the way, the conventional humeral artificial head has a convex regular spherical head, and the corresponding glenoid component has a concave regular spherical shape, and the relationship between the two is a so-called ball and socket, which is similar to the original human shoulder. The mechanism is very different from that of a joint. In other words, the original movement mode of the shoulder joint is rotational movement like a rolling ball, sideways sliding movement, and rotational movement, and the artificial head and glenoid components required by such a shoulder joint have the following shapes:
The artificial femoral head is required to have an elliptical convex surface, and the glenoid component is required to have a concave curved surface.
Conventional prosthetic head and glenoid components do not adequately meet this need. Further, the glenoid component of the present invention has three to five crest-shaped wings, and has a structure that prevents abnormal rotational movement and makes it difficult to come off when inserted into the scapula.
In addition, the present invention provides for right shoulders which have a mirror surface relationship with each other;
A separate component is created for the left shoulder. A glenoid component like this has never been seen before.

Example In a glenoid component made of HDP, the sliding part exhibits a spherical trajectory created when a sphere with a diameter of 38 mm moves 7.5 mm in parallel on a plane, that is, a smooth concave curved surface, and the outer ring has a center-to-center distance of l.
mm, small circle a 14mm apart: diameter 12mm and large circle b: diameter
24mm, and convex curve c inscribed in these: diameter 96mm
Circle, circumscribing concave curve d: It is composed of each arc of a circle with a diameter of 72 mm, and the centers of circles b, c, and circle d are
If ゜, c゜, d゜, angle ∠d゜b゜c゜=33
The thickness of the sliding part is 4 mm, and the stem part is composed of four crest-shaped wings intersecting each other at right angles, each wing having a height of 2.0 mm.
It has a small protrusion of mm in diameter, starts 5 mm inward from the outer ring edge of the sliding part, and converges in a curve at a point 18 mm behind the sliding surface, and the thickness of each blade is 4 mm.

We hereby propose that the glenoid component of the present invention and the artificial femoral head related to the invention already described in the patent application (1) filed on the same date, namely, the femoral head, neck,
In the artificial head of the humerus, which consists of a stem, the femoral head has a shape obtained by cutting out a small part from an elliptical sphere, and extending a symmetrical three-dimensional shape downward at the cut end, and the neck has dorsal fins A and a pair of fins. side fin of
B ₁ , B ₂ , and lower fins C; dorsal fin A has three small holes and has a convex curve; and a pair of lateral fins B ₁ , B ₂
has two small holes each and a convex curve, the lower fin C has a concave curve, and the stem has an oval cross section. It has been used on patients who had previously experienced pain, and the patient was able to achieve pain-free shoulder joint movement after surgery. It is expected that the present invention will be of great help in the reconstruction of dysfunctional shoulders in the future.

[Brief explanation of the drawing]

Figure 1: Front view of the present invention, Figure 2
Figure: A view of the present invention viewed from the side. Figure 3: A view of the present invention viewed from above. The shaded area represents the cross section of the sliding part, and this figure refers to the right shoulder. shall be.

Claims (1)

[Claims] 1 In the glenoid component, the sliding part has a concave curved surface, and the outer ring of the sliding part has a small circle a, a large circle b whose centers are separated by 1 mm, and a convex curve c and a concave curve d that are in contact with these. It is composed of
A glenoid component made of HDP whose stem is composed of three or more crest-shaped wings.