Artificial joint
The artificial joint with a tapered hinge and adjustable stems addresses the mismatch in bone resection surfaces, ensuring a secure fit and reducing stress concentration, thereby reducing the risk of osteophyte formation and breakage.
Patent Information
- Application Number
- JP2024079466
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2025-11-28
AI Technical Summary
Conventional artificial joints for the proximal interphalangeal joint do not adequately match the size of the resected surfaces of the proximal and distal bones, leading to potential issues with hinge sizing and stress concentration.
The artificial joint features a hinge with a tapered shape and adjustable dimensions, including stems with varying widths and cross-sectional shapes to fit the resection surfaces of the bones, preventing stress concentration and breakage.
The design allows for precise adjustment of the hinge size to match bone resection surfaces, reducing the risk of osteophyte formation and breakage, while minimizing the amount of bone resection required.
Smart Images
Figure 2025173744000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to artificial joints. [Background technology]
[0002] One known artificial joint is implanted in the proximal interphalangeal joint (PIP joint) (Patent Document 1). In this technology, the artificial joint is composed of a proximal stem inserted into the cavity of the proximal phalanx, a distal stem inserted into the cavity of the middle phalanx, and a hinge interposed between the proximal and distal stems to enable the proximal and distal stems to flex relative to each other. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent No. 4679789 Summary of the Invention [Problem to be solved by the invention]
[0004] An artificial joint is implanted after resecting the distal end of the proximal bone and the proximal end of the distal bone. The amount of resection of each bone differs between the proximal and distal bones. When the artificial joint is implanted in the joint, the hinge is positioned between the resected surface of the proximal bone and the resected surface of the distal bone. However, in conventional artificial joints, the hinge size does not match the size of the resected surface of each bone.
[0005] Therefore, an object of the present invention is to provide an artificial joint in which the size of the hinge can be adjusted to the size of the resected surface of each bone. [Means for solving the problem]
[0006] The artificial joint is an artificial joint applied to the proximal interphalangeal joint or metacarpophalangeal joint, and has a proximal stem inserted into a hole in a first bone located on the proximal side of the joint, a distal stem inserted into a hole in a second bone located on the distal side of the joint, and a hinge that rotatably connects the proximal stem and the distal stem, the hinge having a proximal wall facing the distal end of the first bone, a distal wall facing the proximal end of the second bone, and a connecting portion that connects the proximal wall and the distal wall, and the maximum width in the left-right direction of the proximal wall is smaller than the maximum width in the left-right direction of the distal wall.
[0007] The maximum width in the left-right direction of the proximal wall of the hinge is smaller than the maximum width in the left-right direction of the distal wall, so that the size of the hinge can be adjusted to the size of the resection surface of each bone.
[0008] The hinge may have a tapered shape in which the width in the left-right direction decreases from the distal end of the distal wall toward the proximal end of the proximal wall.
[0009] By making the hinge have a tapered shape, the change in shape of the hinge can be made gentler, and therefore, stress can be prevented from concentrating on the hinge.
[0010] At least one of the proximal stem and the distal stem has a connection end connected to the hinge, and the connection end may have a cross-sectional shape such that the end farther from the hinge has a rectangular shape, and each side of the rectangle bulges outward in an arc as it approaches the hinge.
[0011] The connecting end of the stem has a cross-sectional shape in which each side of a rectangle bulges outward in an arch shape as it approaches the hinge, thereby preventing stress from concentrating at the connection between the stem and the hinge.
[0012] The proximal stem and the distal stem may have a tapered shape in which their width in the left-right direction decreases as they move away from the hinge, and the left-right width of the distal end of the proximal stem may be smaller than the left-right width of the proximal end of the distal stem.
[0013] The stems have a tapered shape in which the width in the left-right direction decreases as they move away from the hinge, and the width in the left-right direction at the distal end of the proximal stem is smaller than the width in the left-right direction at the proximal end of the distal stem, allowing each stem to be adjusted to the size of the corresponding bone.
[0014] The proximal end of the proximal wall may be sized to cover the distal end of the first bone, and the distal end of the distal wall may be sized to cover the proximal end of the second bone.
[0015] The proximal stem may be longer than the distal stem. [Effects of the Invention]
[0016] The hinge size can be adapted to the size of the resection surface of each bone. [Brief explanation of the drawings]
[0017] [Figure 1] FIG. 1 is a perspective view showing an artificial joint according to a first embodiment. [Figure 2] The prosthesis is implanted into the proximal interphalangeal joint, as seen from above (a) and from the right (b). [Figure 3] The artificial joint is shown as seen from above (a), below (b), and from the right (c). [Figure 4] (a) is a perspective view of the artificial joint seen from the proximal side, and (b) is a view from the proximal side. [Figure 5] (a) is a perspective view of the artificial joint seen from the distal side, and (b) is a view from the distal side. [Figure 6] (a) shows the proximal interphalangeal joint, and (b) shows the state after the distal end of the proximal phalanx and the proximal end of the middle phalanx have been removed. [Figure 7] FIG. 10 is a perspective view showing an artificial joint according to a second embodiment. [Figure 8] The prosthesis is implanted into the metacarpophalangeal joint, as seen from above (a) and from the right (b). [Figure 9] The artificial joint is shown as seen from above (a), below (b), and from the right (c). [Figure 10] (a) is a perspective view of the artificial joint seen from the proximal side, and (b) is a view from the proximal side. [Figure 11] (a) is a perspective view of the artificial joint seen from the distal side, and (b) is a view from the distal side. DETAILED DESCRIPTION OF THE INVENTION
[0018] Next, a first embodiment will be described. The artificial joint 1A of the first embodiment shown in FIG. 1 is an artificial joint applied to the proximal interphalangeal joint (hereinafter referred to as the "PIP joint"). The artificial joint 1A integrally comprises a proximal stem 10, a distal stem 20, and a hinge 30. The artificial joint 1A is made of, for example, a silicone resin, and the proximal stem 10, the distal stem 20, and the hinge 30 are molded integrally. The artificial joint 1A has a bilaterally symmetrical shape.
[0019] As shown in Figures 2(a) and (b), the proximal stem 10 is a portion that is inserted into a hole 521 in a proximal phalanx 52, which is an example of a first bone. The proximal phalanx 52 is a bone located on the proximal side of the PIP joint. The proximal side refers to the side closer to the trunk. The hole 521 is, for example, the medullary cavity of the proximal phalanx 52. The proximal stem 10 has a tapered shape in which its width in the left-right direction decreases as it moves away from the hinge 30.
[0020] The distal stem 20 is a portion that is inserted into a hole 531 in the middle phalanx 53, which is an example of a second bone. The middle phalanx 53 is a bone located distal to the PIP joint. The distal side refers to the side farther from the trunk. The hole 531 is, for example, the medullary cavity of the middle phalanx 53. The distal stem 20 has a tapered shape in which its width in the left-right direction decreases as it moves away from the hinge 30.
[0021] The hinge 30 is a part that rotatably connects the proximal stem 10 and the distal stem 20. The hinge 30 connects the proximal stem 10 and the distal stem 20 so as to enable bending and straightening movements of the joint. The hinge 30 has a proximal wall 31, a distal wall 32, a connecting portion 33, and a restricting portion 34.
[0022] The proximal wall 31 is a portion that faces the distal end 52E of the proximal phalanx 52. The proximal wall 31 is disposed so as to cover the distal end 52E of the proximal phalanx 52. The distal wall 32 is a portion that faces the proximal end 53E of the middle phalanx 53. The distal wall 32 is disposed so as to cover the proximal end 53E of the middle phalanx 53. The connecting portion 33 is a portion that connects the proximal wall 31 and the distal wall 32. The connecting portion 33 connects the lower portions of the proximal wall 31 and the distal wall 32 to each other.
[0023] The right side surface of the proximal wall 31, the right side surface of the connecting portion 33, and the right side surface of the distal wall 32 are flush with each other. The left side surface of the proximal wall 31, the left side surface of the connecting portion 33, and the left side surface of the distal wall 32 are flush with each other.
[0024] The restricting portion 34 is a portion that restricts the rotation range of the distal stem 20 relative to the proximal stem 10. As shown in FIG. 2(b), the restricting portion 34 is formed to protrude from the upper end of the proximal wall 31 toward the distal wall 32. When the distal stem 20 is rotated relative to the proximal stem 10 so that the upper ends of the proximal wall 31 and the distal wall 32 approach each other, the restricting wall 34 comes into contact with the distal wall 32, thereby restricting further rotation of the distal stem 20 relative to the proximal stem 10.
[0025] The artificial joint 1A has rounded corners and corners. Specifically, the proximal stem 10, the distal stem 20, and the hinge 30 have rounded corners. In addition, the corner formed at the connection between the proximal stem 10 and the hinge 30 and the corner formed at the connection between the distal stem 20 and the hinge 30 are rounded. In addition, the corner formed at the connection between the proximal wall 31 and the connection portion 33, the corner formed at the connection between the distal wall 32 and the connection portion 33, and the corner formed at the connection between the proximal wall 31 and the restriction portion 34 are rounded.
[0026] 3(a), the maximum width WH1 in the left-right direction of the proximal wall 31 is smaller than the maximum width WH2 in the left-right direction of the distal wall 32. As shown in FIGS. 3(a) and 3(b), the hinge 30 has a tapered shape in which the width in the left-right direction decreases from the distal end 32E of the distal wall 32 toward the proximal end 31E of the proximal wall 31.
[0027] 3(c), the maximum width WH3 in the vertical direction of the proximal wall 31 is smaller than the maximum width WH4 in the vertical direction of the distal wall 32. In the first embodiment, the hinge 30 has a tapered shape (see imaginary lines) in which the width in the vertical direction decreases from the distal end 32E of the distal wall 32 to the proximal end 31E of the proximal wall 31.
[0028] The proximal stem 10 is longer than the distal stem 20. Specifically, the length L1 of the proximal stem 10 is longer than the length L2 of the distal stem 20. As shown in FIG. 3(b), in the first embodiment, the width WS1 in the left-right direction of the distal end 10E of the proximal stem 10 is approximately the same as the width WS2 in the left-right direction of the proximal end 20E of the distal stem 20.
[0029] 2(a) and 2(b), the proximal end 31E of the proximal wall 31 has a size that covers the distal end 52E of the proximal phalanx 52. Specifically, the width in the left-right direction of the proximal end 31E of the proximal wall 31 is approximately the same as the width in the left-right direction of the distal end 52E of the proximal phalanx 52. In addition, the width in the up-down direction of the proximal end 31E of the proximal wall 31 is approximately the same as the width in the up-down direction of the distal end 52E of the proximal phalanx 52.
[0030] The distal end 32E of the distal wall 32 has a size that covers the proximal end 53E of the middle phalanx 53. Specifically, the width in the left-right direction of the distal end 32E of the distal wall 32 is approximately the same as the width in the left-right direction of the proximal end 53E of the middle phalanx 53. In addition, the width in the up-down direction of the distal end 32E of the distal wall 32 is approximately the same as the width in the up-down direction of the proximal end 53E of the middle phalanx 53.
[0031] As shown in FIGS. 4(a) and (b), the proximal stem 10 is formed to extend proximally from the proximal end 31E of the proximal wall 31 of the hinge 30. The proximal stem 10 has a connection end 11 connected to the proximal wall 31 of the hinge 30. As shown by imaginary lines in FIGS. 4(a) and (b), the cross-sectional shape of the connection end 11 at the proximal end 11E is a rectangle whose length is longer in the left-right direction. The proximal end 11E of the connection end 11 is the end of the connection end 11 farthest from the hinge 30. The connection end 11 has a cross-sectional shape in which each side of the rectangle bulges outward in an arch shape as it approaches the hinge 30 from the proximal end 11E. The connection end 11 (proximal stem 10) has a cross-sectional shape at the distal end 10E that resembles an ellipse.
[0032] As shown in FIGS. 5(a) and 5(b), the distal stem 20 is formed to extend distally from the distal end 32E of the distal wall 32 of the hinge 30. The distal stem 20 has a connection end 21 connected to the distal wall 32 of the hinge 30. As shown by imaginary lines in FIGS. 5(a) and 5(b), the cross-sectional shape of the connection end 21 at the distal end 21E is rectangular. More specifically, the cross-sectional shape of the connection end 21 at the distal end 21E is a rectangle that is elongated in the left-right direction. The distal end 21E of the connection end 21 is the end of the connection end 21 far from the hinge 30. The connection end 21 has a cross-sectional shape in which each side of the rectangle bulges outward in an arch shape as it approaches the hinge 30 from the distal end 21E. The connection end 21 (distal stem 20) has a cross-sectional shape at the proximal end 20E that resembles an ellipse.
[0033] The artificial joint 1A can be prepared in a variety of sizes depending on the type of finger (such as index finger or middle finger) and the size of fingers, which differ depending on gender, physique, etc.
[0034] Next, an example of a method for implanting the artificial joint 1A into a joint will be described. First, as shown in Figures 6(a) and 6(b), the distal end of the proximal phalanx 52 and the proximal end of the middle phalanx 53 are resected. At this time, the amount of resection at the distal end of the proximal phalanx 52 is greater than the amount of resection at the proximal end of the middle phalanx 53. Therefore, the area of the resected surface of the proximal phalanx 52 (distal end 52E) is smaller than the area of the resected surface of the middle phalanx 53 (proximal end 53E).
[0035] 2(a) and 2(b), the proximal stem 10 is inserted into the hole 521 of the proximal phalanx 52, and the distal stem 20 is inserted into the hole 531 of the middle phalanx 53. Then, the hinge 30 is positioned between the resected surface of the proximal phalanx 52 (distal end 52E) and the resected surface of the middle phalanx 53 (proximal end 53E). The proximal wall 31 of the hinge 30 covers the resected surface of the proximal phalanx 52 (distal end 52E), and the distal wall 32 covers the resected surface of the middle phalanx 53 (proximal end 53E).
[0036] Next, the effects of the artificial joint 1A of the first embodiment will be described. The maximum width WH1 in the left-right direction of the proximal wall 31 of the hinge 30 is smaller than the maximum width WH2 in the left-right direction of the distal wall 32, so that the size of the hinge 30 can be adjusted to the size of the resection surface of each bone 52, 53. This makes it possible to suppress, for example, the formation of osteophytes on the resection surface of each bone 52, 53.
[0037] The hinge 30 has a tapered shape in which the width in the left-right direction decreases from the distal end 32E to the proximal end 31E, which, for example, makes it difficult for corners to form and allows the shape of the hinge 30 to change gradually, thereby preventing stress from concentrating on the hinge 30. This makes it possible to prevent the hinge 30 from breaking, for example.
[0038] The connection ends 11, 21 of the stems 10, 20 have a cross-sectional shape in which each side of a rectangle bulges outward in an arch shape as it approaches the hinge 30, which makes it possible to prevent stress from concentrating at the connection between the stems 10, 20 and the hinge 30. This makes it possible to prevent, for example, the stems 10, 20 and the hinge 30 from breaking.
[0039] Compared to conventional artificial joints of the same size, the artificial joint 1A has a smaller dimension from the proximal end 31E of the proximal wall 31 to the distal end 32E of the distal wall 32. This allows the amount of bone 52, 53 that needs to be resected to be smaller.
[0040] Next, a second embodiment will be described. In the following, the same components as those of the artificial joint 1A of the first embodiment will be denoted by the same reference numerals, and the same points as those of the first embodiment will be omitted as appropriate, and only the points different from the first embodiment will be described in detail.
[0041] The artificial joint 1B of the second embodiment shown in FIG. 7 is an artificial joint applied to a metacarpophalangeal joint (hereinafter referred to as "MP joint"). The artificial joint 1B has a proximal stem 10, a distal stem 20, and a hinge 30 integrally formed. The artificial joint 1B is made of, for example, a silicone resin, and the proximal stem 10, the distal stem 20, and the hinge 30 are molded integrally. The artificial joint 1B has a bilaterally symmetrical shape.
[0042] 8(a) and 8(b), the proximal stem 10 is inserted into a hole 511 in a metacarpal bone 51, which is another example of a first bone. The metacarpal bone 51 is a bone located proximal to the MP joint. The hole 511 is, for example, the medullary cavity of the metacarpal bone 51.
[0043] The distal stem 20 is inserted into a hole 522 in the proximal phalanx 52, which is another example of a second bone. The proximal phalanx 52 is a bone located distal to the MP joint. The hole 522 is, for example, the medullary cavity of the proximal phalanx 52.
[0044] The hinge 30 has a proximal wall 31 , a distal wall 32 and a connecting portion 33 . The proximal wall 31 faces the distal end 51E of the metacarpal bone 51. The proximal wall 31 is disposed so as to cover the distal end 51E of the metacarpal bone 51. The distal wall 32 faces the proximal end 52F of the proximal phalanx 52. The distal wall 32 is positioned to cover the proximal end 52F of the proximal phalanx 52.
[0045] The artificial joint 1B has rounded corners and edges, similar to the artificial joint 1A of the first embodiment.
[0046] 9(a), the maximum width WH5 of the proximal wall 31 in the left-right direction is smaller than the maximum width WH6 of the distal wall 32. As shown in FIGS. 9(a) and 9(b), the hinge 30 has a tapered shape in which the width in the left-right direction decreases from the distal end 32E of the distal wall 32 toward the proximal end 31E of the proximal wall 31.
[0047] As shown in FIG. 9(c), in the second embodiment, the maximum width WH7 of the proximal wall 31 in the vertical direction is larger than the maximum width WH8 of the distal wall 32 in the vertical direction.
[0048] The length L3 of the proximal stem 10 is longer than the length L4 of the distal stem 20. As shown in Fig. 9(b), in the second embodiment, the width WS3 in the left-right direction of the distal end 10E of the proximal stem 10 is smaller than the width WS4 in the left-right direction of the proximal end 20E of the distal stem 20. Since the stems 10, 20 have a tapered shape in which the width in the left-right direction decreases with increasing distance from the hinge 30, in the second embodiment, the proximal stem 10 has a narrower width in the left-right direction than the distal stem 20.
[0049] 8(a) and 8(b), the proximal end 31E of the proximal wall 31 has a size that covers the distal end 51E of the metacarpal bone 51. Specifically, the width in the left-right direction of the proximal end 31E of the proximal wall 31 is approximately the same as the width in the left-right direction of the distal end 51E of the metacarpal bone 51. In addition, the width in the up-down direction of the proximal end 31E of the proximal wall 31 is approximately the same as the width in the up-down direction of the distal end 51E of the metacarpal bone 51.
[0050] The distal end 32E of the distal wall 32 has a size that covers the proximal end 52F of the proximal phalanx 52. Specifically, the left-right width of the distal end 32E of the distal wall 32 is approximately the same as the left-right width of the proximal end 52F of the proximal phalanx 52. Furthermore, the up-down width of the distal end 32E of the distal wall 32 is approximately the same as the up-down width of the proximal end 52F of the proximal phalanx 52.
[0051] As shown in Figures 10(a) and 10(b), the cross-sectional shape of the connection end 11 of the proximal stem 10 at the proximal end 11E is rectangular. More specifically, the cross-sectional shape of the connection end 11 at the proximal end 11E is a rectangle that is close to a square. The connection end 11 has a cross-sectional shape in which each side of the rectangle bulges outward in a bow shape as it approaches the hinge 30 from the proximal end 11E. The cross-sectional shape of the connection end 11 (proximal stem 10) at the distal end 10E is a shape that resembles a circle.
[0052] As shown in Figures 11(a) and 11(b), the cross-sectional shape of the distal end 21E of the connection end 21 of the distal stem 20 is rectangular. More specifically, the cross-sectional shape of the distal end 21E of the connection end 21 is rectangular with its longer sides in the left-right direction. The cross-sectional shape of the connection end 21 is such that each side of the rectangle bulges outward in a bow shape as it approaches the hinge 30 from the distal end 21E. The cross-sectional shape of the proximal end 20E of the connection end 21 (distal stem 20) is oval-like.
[0053] A plurality of different sizes of artificial joint 1B can be prepared according to the type and size of the finger.
[0054] Next, the effects of the artificial joint 1B of the second embodiment will be described. The maximum width WH5 in the left-right direction of the proximal wall 31 of the hinge 30 is smaller than the maximum width WH6 in the left-right direction of the distal wall 32, so that the size of the hinge 30 can be adjusted to the size of the resection surfaces of the bones 51 and 52. This makes it possible to prevent osteophytes from forming on the resection surfaces of the bones 51 and 52, for example.
[0055] The hinge 30 has a tapered shape in which the width in the left-right direction decreases from the distal end 32E to the proximal end 31E, which, for example, makes it difficult for corners to form and allows the shape of the hinge 30 to change gradually, thereby preventing stress from concentrating on the hinge 30. This makes it possible to prevent the hinge 30 from breaking, for example.
[0056] The connection ends 11, 21 of the stems 10, 20 have a cross-sectional shape in which each side of a rectangle bulges outward in an arch shape as it approaches the hinge 30, which makes it possible to prevent stress from concentrating at the connection between the stems 10, 20 and the hinge 30. This makes it possible to prevent, for example, the stems 10, 20 and the hinge 30 from breaking.
[0057] The stems 10, 20 have a tapered shape in which the width in the left-right direction decreases with increasing distance from the hinge 30, and the width WS3 in the left-right direction of the distal end 10E of the proximal stem 10 is smaller than the width WS4 in the left-right direction of the proximal end 20E of the distal stem 20, so that each stem 10, 20 can be adjusted to the size of the corresponding bones 51, 52. More specifically, the proximal stem 10 can be adjusted to the size of the metacarpal bone 51, and the distal stem 20 can be adjusted to the size of the proximal phalanx 52.
[0058] Although the embodiment has been described above, the artificial joint can be modified as appropriate as exemplified below. For example, the proximal and distal stems may be approximately the same length.
[0059] In the above embodiment, the connection ends 11, 21 of the stems 10, 20 each have a cross-sectional shape in which each side of a rectangle bulges outward in an arc shape as it approaches the hinge 30. However, for example, only one of the proximal stem and the distal stem may have such a cross-sectional shape. Also, for example, the cross-sectional shape of the connection ends of the proximal stem and the distal stem may be rectangular throughout the entire length of the stem.
[0060] In the above embodiment, the entire hinge 30 has a tapered shape, but, for example, only a portion of the hinge may have a tapered shape. Specifically, one of the proximal wall and the distal wall and the connecting portion may have a tapered shape in which the width in the left-right direction decreases from the distal side to the proximal side. Furthermore, the connecting portion may have a tapered shape in which the width in the left-right direction decreases from the distal side to the proximal side. The proximal wall may have a constant width in the left-right direction. The distal wall may have a constant width in the left-right direction.
[0061] The elements described in the embodiments and modifications may be implemented in any combination. [Explanation of symbols]
[0062] 1A,1B Artificial joint 10 Proximal stem 10E distal end 11 Connection end 11E proximal end 20 Distal stem 20E proximal end 21 Connection end 21E distal end 30 Hinge 31 Proximal wall 31E proximal end 32 Distal wall 32E distal end 33 Connection 51 Metacarpus 51E distal end 52 Proximal phalanx 52E distal end 52F proximal end 53 Middle phalanx 53E proximal end 511,521,522,531 holes
Claims
1. An artificial joint applied to the proximal interphalangeal joint or metacarpophalangeal joint, a proximal stem inserted into a hole in a first bone located proximal to the joint; a distal stem inserted into a hole in a second bone located distal to the joint; a hinge that pivotally connects the proximal stem and the distal stem, The hinge is a proximal wall facing the distal end of the first bone; a distal wall facing the proximal end of the second bone; a connecting portion connecting the proximal wall and the distal wall, An artificial joint, characterized in that the maximum width in the left-right direction of the proximal wall is smaller than the maximum width in the left-right direction of the distal wall.
2. 2. The artificial joint according to claim 1, wherein the hinge has a tapered shape in which the width in the left-right direction decreases from the distal end of the distal wall to the proximal end of the proximal wall.
3. At least one of the proximal stem and the distal stem has a connecting end connected to the hinge; The artificial joint according to claim 1, characterized in that the cross-sectional shape of the connection end is rectangular at the end farthest from the hinge, and each side of the rectangle bulges outward in a bow shape as it approaches the hinge.
4. the proximal stem and the distal stem have a tapered shape in which their widths in the left-right direction decrease as they move away from the hinge; The artificial joint according to claim 1, wherein the width of the distal end of the proximal stem in the left-right direction is smaller than the width of the proximal end of the distal stem in the left-right direction.
5. a proximal end of the proximal wall sized to cover a distal end of the first bone; The artificial joint of claim 1 , wherein the distal end of the distal wall is sized to cover the proximal end of the second bone.
6. The prosthesis of claim 1, wherein the proximal stem is longer than the distal stem.
Citation Information
Patent Citations
Artificial joint component and method having multiple arc-shaped bends
JP4679789B2