Biological implant and surgical instrument

Abstract

A biological implant according to the present invention comprises an acetabular cup and a liner that has an outer surface in contact with the acetabular cup and is positioned on the inner side of the acetabular cup. The liner has a first tapered surface that is positioned at the peripheral edge of the outer surface and is in contact with the peripheral edge of the inner surface of the acetabular cup. The first tapered surface has a protrusion.

Description

Bioimplants and surgical instruments

[0001] The present disclosure relates to bioimplants and surgical instruments used in hip replacement surgery.

[0002] Total hip arthroplasty, which replaces the hip joint with an artificial joint, is known. Total hip arthroplasty involves placing a cup (shell) in the pelvis, fitting a liner to the inner surface of the cup, inserting a stem into the femur, and attaching a femoral head (ball) to the tip of the stem, which acts as the femoral head. The femoral head ball is then placed so that it slides within the liner, thereby reproducing the ball-and-socket motion of the hip joint.

[0003] Also known is an artificial joint called a dual mobility system, which allows for a wider range of motion in ball movement than conventional artificial joints. In the dual mobility system, a bearing is placed between the femoral head ball and the liner, and the bearing slides on the inner surface of the liner, while the femoral head ball slides on the inner surface of the bearing, thereby widening the range of motion in ball movement (Patent Document 1).

[0004] Japan Special Table No. 2019-531139

[0005] "NOVAE, Dual Mobility Cups, Surgical Technique", [online], [Retrieved February 1, 2024], Internet<URL:https: / / fischermedical.dk / wp-content / uploads / NOVAE_Surgical-Technique_EN_Ed-4-2018.pdf> "BI-MENTUM, Dual Mobility System, Surgical Technique", [online], [Retrieved February 1, 2024], Internet <https: / / synthes.vo.llnwd.net / o16 / LLNWMB8 / INT%20Mobile / Synthes%20International / Product%20Support%20Material / legacy_Synthes_PDF / 096052.pdf>

[0006] In one aspect of the present disclosure, a biological implant comprises an acetabular cup and a liner positioned inside the acetabular cup, the liner having an outer surface that contacts the acetabular cup, the liner being positioned on the periphery of the outer surface and having a first tapered surface that contacts the periphery of the inner surface of the acetabular cup, the first tapered surface having a protrusion.

[0007] 1. A schematic diagram illustrating an example of a method for attaching a biological implant according to embodiment 1 of the present disclosure.

[0023] FIG. 1 is an exploded perspective view illustrating an example of the biological implant shown in FIG. 1.

[0024] FIG. 12 is a perspective view and a cross-sectional view illustrating an example of an acetabular cup shown in FIG. 1.

[0025] FIG. 13 is a perspective view and a cross-sectional view illustrating an example of a liner shown in FIG. 1.

[0026] FIG. 14 is a perspective view and a cross-sectional view illustrating an example of a bearing shown in FIG. 1.

[0027] FIG. 15 is a cross-sectional view illustrating a state in which the components of the biological implant shown in FIG. 1 are combined.

[0028] FIG. 16 is a schematic view illustrating the range of motion of the biological implant shown in FIG. 1.

[0029] FIG. 17 is a schematic view illustrating a protrusion formed on the liner shown in FIG. 1.

[0030] FIG. 18 is a schematic view illustrating tapered fitting between the liner and acetabular cup shown in FIG. 1.

[0031] FIG. 19 is a schematic view illustrating the thickness of the liner shown in FIG. 1.

[0032] FIG. 19 is a front view illustrating an example of a surgical instrument according to embodiment 2 of the present disclosure.

[0033] FIG. 11 is a perspective view of the surgical instrument shown in FIG. 12.

[0034] FIG. 19 is a schematic view illustrating a ratchet structure of the surgical instrument shown in FIG. 12.

[0008] First Embodiment Overview First, to facilitate understanding of the biological implant 1, an overview of the steps of total hip replacement surgery will be briefly described with reference to Fig. 1. Fig. 1 is a schematic diagram illustrating an example of a method for attaching the biological implant 1 according to the first embodiment of the present disclosure.

[0009] 1, a hip joint 91 is composed of a ball-shaped femoral head (not shown) at the tip of a femur 92 and a dome-shaped recessed acetabulum 94 on the side of a pelvis 93. When the hip joint 91 is damaged by disease or a fracture, an artificial hip joint replacement surgery is performed to replace the damaged hip joint 91 with an artificial hip joint.

[0010] The bioimplant 1 according to the first embodiment of the present disclosure can be used as an artificial hip joint in total hip replacement surgery. The bioimplant 1 is composed of a combination of an acetabular cup 2, a liner 3, a bearing 4, and a femoral head ball 5.

[0011] In total hip replacement surgery, first, the acetabulum 94 on the pelvis 93 side is thinned and an acetabular cup 2 is attached. Next, a liner 3 is fitted into the acetabular cup 2. Meanwhile, on the femur 92 side, a stem 90 is inserted into the femur 92 from which the femoral head has been removed, and a femoral head ball 5 fitted into a bearing 4 is attached to the tip 901 of the stem 90. The stem 90 may be inserted into the femur 92 with the femoral head ball 5 attached to the tip 901 of the stem 90, and the femoral head ball 5 may be fitted into the bearing 4. The liner 3 on the pelvis 93 side and the bearing 4 on the femur 92 side are engaged to function as an artificial hip joint.

[0012] <Configuration of the bioimplant 1> Fig. 2 is an exploded perspective view showing an example of the bioimplant 1. As shown in Fig. 2, the bioimplant 1 is configured by combining an acetabular cup 2, a liner 3, a bearing 4, and a femoral head ball 5.

[0013] The biological implant 1 has a so-called dual mobility (double sliding) structure. The outer surface 41 of the bearing 4, which is disposed between the liner 3 and the femoral head ball 5, slides against the inner surface 32 of the liner 3, and the inner surface 42 slides against the outer surface 51 of the femoral head ball 5. By allowing the biological implant 1 to slide in double motion in this way, the range of motion of the biological implant 1 can be widened.

[0014] 3A and 3B are perspective views showing an example of an acetabular cup 2. The views designated by reference numerals 300A and 300B are perspective views of the acetabular cup 2, and the view designated by reference numeral 300C is a cross-sectional view of the acetabular cup 2 taken along line III-III shown in 300A. C2 indicates the central axis of the acetabular cup 2 in the fitting direction.

[0015] 2 and 3, the acetabular cup 2 has an outer surface 21, an inner surface 22, an accommodation space 23, and an insertion hole 24. The acetabular cup 2 has a dome-like (approximately hemispherical bowl-like) shape. Here, the term "approximately hemispherical" refers not only to a geometric hemispherical shape, but also to a shape in which a portion of the hemisphere is missing, or a shape having a region protruding from a portion of the hemisphere, etc.

[0016] A second tapered surface 221 is located around the entire circumferential direction near a peripheral edge 222 of the inner surface 22. The second tapered surface 221 is shaped so that the diameter of the inner surface 22 increases toward the peripheral edge 222.

[0017] The receiving space 23 is a space for fitting the liner 3. The receiving space 23 is located inside the acetabular cup 2. The diameter of the receiving space 23 is slightly larger than the diameter of the liner 3. This allows the liner 3 to be fitted into the receiving space 23 of the acetabular cup 2, and the liner 3 is fixed to the acetabular cup 2.

[0018] The insertion hole 24 is located at the top of the acetabular cup 2. A protrusion 34 of the liner 3, which will be described later, is inserted into the insertion hole 24.

[0019] 4A and 4B are perspective views showing an example of the liner 3. The view indicated by the reference numeral 400A is a perspective view of the liner 3, the view indicated by the reference numeral 400B is a front view, and the view indicated by the reference numeral 400C is a cross-sectional view taken along the line IV-IV shown in 400A. C3 indicates the central axis of the liner 3 in the fitting direction.

[0020] 2 and 4, the liner 3 includes an outer surface 31, an inner surface 32, an accommodating space 33, and a protrusion 34. The liner 3 has a dome-like (substantially hemispherical bowl-like) shape.

[0021] A first tapered surface 311 is located around the entire circumferential direction near a peripheral edge 312 of the outer surface 31. The diameter of the first tapered surface 311 of the outer surface 31 increases as it approaches the peripheral edge 312.

[0022] As described above, the protrusion 34 is inserted into the insertion hole 24 of the acetabular cup 2. The liner 3 having the protrusion 34 facilitates alignment when inserting the liner 3 into the acetabular cup 2. The liner 3 does not necessarily have to have the protrusion 34.

[0023] The accommodation space 33 is a space for fitting the bearing 4. The accommodation space 33 is located inside the liner 3. The diameter of the accommodation space 33 is slightly larger than the diameter of the bearing 4. This allows the bearing 4 to be fitted into the accommodation space 33 of the liner 3. The bearing 4 fitted into the accommodation space 33 is held in the liner 3 so that the outer surface 41 of the bearing 4 and the inner surface 32 of the liner 3 slide against each other.

[0024] 5A and 5B are perspective views showing an example of a bearing 4. The view indicated by reference numeral 500A is a perspective view of the bearing 4, the view indicated by reference numeral 500B is a front view, and the view indicated by reference numeral 500C is a cross-sectional view taken along line V-V shown in 500A. C4 indicates the central axis of the bearing 4 in the fitting direction.

[0025] 2 and 5, the bearing 4 includes an outer surface 41, an inner surface 42, an accommodating space 43, and an opening 44. The bearing 4 is made of a resin such as polyethylene.

[0026] The accommodation space 43 is a space for fitting the femoral head ball 5, and is formed inside the bearing 4. The diameter of the accommodation space 43 is formed to be slightly larger than the diameter of the femoral head ball 5. This allows the femoral head ball 5 to be fitted into the accommodation space 43 of the bearing 4. The bearing 4 fits the femoral head ball 5 within the accommodation space 43 so as to cover most of the outer surface 51 of the femoral head ball 5.

[0027] The femoral head ball 5 is fitted into the receiving space 43 in a state in which the inner surface 42 of the bearing 4 and the outer surface 51 of the femoral head ball 5 are slidable against each other. The outer surface 41 of the bearing 4 slides against the inner surface 32 of the liner 3, and the inner surface 42 slides against the outer surface 51 of the femoral head ball 5.

[0028] The opening 44 has a shape in which the diameter of the opening 44 is smaller than the diameter of the femoral head ball 5. Therefore, a strong pushing force is required to fit the femoral head ball 5 into the bearing 4, and a fitting instrument 6 (surgical instrument) described below is used.

[0029] 6A and 6B are perspective views showing an example of a femoral head ball 5. The view indicated by reference numeral 600A is a perspective view of the femoral head ball 5, the view indicated by reference numeral 600B is a front view, and the view indicated by reference numeral 600C is a cross-sectional view taken along line VI-VI shown in 600A. C5 indicates the central axis of the femoral head ball 5 in the fitting direction.

[0030] 2 and 6 , the femoral head ball 5 has an outer surface 51 and a recess 53. The femoral head ball 5 is fixed to the stem 90 by inserting the tip 901 of the stem 90 into the recess 53. When attaching the femoral head ball 5 to a fitting instrument 6 (surgical instrument) described below, the femoral head ball support portion 71 of the fitting instrument 6 is also inserted into the recess 53.

[0031] <Double sliding> Fig. 7 is a cross-sectional view showing the assembled state of the components of the biological implant 1. Fig. 8 is a schematic diagram illustrating the range of motion of the biological implant 1. As shown in Fig. 7, a liner 3 is placed inside the acetabular cup 2, and a bearing 4 is placed inside the liner 3. The inner surface 32 of the liner 3 and the outer surface 41 of the bearing 4 are in slidable contact. Furthermore, a femoral head ball 5 is housed inside the bearing 4, and the inner surface 42 of the bearing 4 and the outer surface 51 of the femoral head ball 5 are in slidable contact.

[0032] As a result, as shown in 800A in Fig. 8, the femoral head ball 5 moves relative to the bearing 4, and as shown in 800B in Fig. 8, the bearing 4 moves relative to the liner 3. In other words, double sliding can be achieved.

[0033] <Protrusion> In total hip replacement surgery, a liner is fitted into the cup after the cup is placed in the acetabulum of the pelvis. It is undesirable for the liner to come off the cup, so the fitting force between the cup and liner should be strong.

[0034] Therefore, the liner 3 may have a protrusion 313 disposed on the first tapered surface 311. Fig. 9 is a schematic diagram illustrating the protrusion 313 formed on the liner 3. As shown in Fig. 9, the protrusion 313 is provided on the outer surface 31 of the liner 3, facing the inner surface 22 of the acetabular cup 2. The tip of the protrusion 313 has an acute angle. The protrusion 313 catches on the inner surface 22 of the acetabular cup 2, thereby strengthening the fit between the acetabular cup 2 and the liner 3.

[0035] The protrusions 313 may be formed by arranging grooves in the first tapered surface 311. By forming grooves, the protrusions 313 can be formed between the grooves. The grooves may be arranged in a direction different from a line connecting any point on the edge of the liner 3 and the apex of the liner 3, i.e., the protrusion 34 (see FIG. 4 ). This allows the protrusions 313 to be arranged in a direction different from the fitting direction of the acetabular cup 2 and the liner 3, thereby strengthening the fit between the acetabular cup 2 and the liner 3. The grooves may be arranged approximately parallel to the edge of the liner 3.

[0036] The protrusion 313 may have a shape that protrudes from the first tapered surface 311. The protrusion 313 may have a shape that protrudes from the first tapered surface 311 toward the acetabular cup 2. The protrusion 313 may protrude in a direction different from a line connecting an arbitrary point on the edge of the liner 3 and the apex of the liner 3.

[0037] The protrusions 313 may have an obtuse tip. For example, the cross section of the protrusions 313 may be triangular, rectangular, trapezoidal, or the like. The protrusions 313 may have a rounded tip. The protrusions 313 may be located on only a portion of the first tapered surface 311. The protrusions 313 may be located around the entire circumference of the liner 3.

[0038] The protrusions 313 may be positioned around the entire circumference of the liner 3, and the tips of the protrusions 313 may be annular in shape. The protrusions 313 may be positioned around the entire circumference of the liner 3, and the tips of the protrusions 313 may be spiral in shape.

[0039] <Tapered Fitting> As described above, the liner 3 has a first tapered surface 311 arranged on the peripheral edge 312 of the surface 31. The first tapered surface 311 fits into the inner surface 22 of the acetabular cup 2, thereby fitting the acetabular cup 2 and the liner 3 together. A second tapered surface 221 may be arranged on the inner surface 22 of the acetabular cup 2, and the first tapered surface 311 of the liner 3 may fit into the second tapered surface 221 of the acetabular cup 2.

[0040] 10 , the first tapered surface 311 may have a biting portion 314 that bites into the second tapered surface 221. The biting portion 314 may be formed by bending the first tapered surface 311 inward at an angle L toward the edge, i.e., toward the center of the circle formed by the edge of the liner 3. In other words, the biting portion 314 may be realized by an edge provided by providing a surface on the first tapered surface 311 whose angle with the mating direction is smaller than the angle of the second tapered surface 221 in a cross section cut along a plane parallel to the mating direction between the acetabular cup 2 and the liner 3. The tip of the biting portion 314 may have an obtuse angle or an acute angle. When the tip of the biting portion 314 has an acute angle, the biting portion 314 bites into the second tapered surface 221 more firmly. When the tip of the biting portion 314 has an obtuse angle, the risk of the tip of the liner 3 chipping the inner surface of the acetabular cup 2 is reduced.

[0041] Since the first tapered surface 311 has the biting portion 314, when the acetabular cup 2 and the liner 3 are fitted together, the biting portion 314 bites into the inner surface of the acetabular cup 2. This strengthens the fit between the acetabular cup 2 and the liner 3.

[0042] 11 is a schematic diagram illustrating the thickness of the liner 3. Here, a straight line that passes through the center P0 of the ring formed by the peripheral portion 312 of the liner 3 and is parallel to the fitting direction of the acetabular cup 2 and the liner 3 is defined as a central axis C3.

[0043] 11 , in a cross section taken along a plane passing through the central axis C3 and parallel to the fitting direction, with one side of the central axis C3 designated as a first side and the other side designated as a second side, the outer shape of the liner 3 includes arcs centered on points that are approximately symmetrical with respect to the central axis C3 on both the first and second sides, i.e., point P1 on the first side and point P2 on the second side. Here, the arcs do not necessarily represent only geometric arcs, but allow for deviations from the geometric arcs due to manufacturing errors and the like.

[0044] As a result, the liner 3 has a region where the thickness W1 of the liner 3 in a cross section including the central axis C3 is larger than when the outer shape is formed by an arc centered at P0 on the central axis C3. The liner 3 has a region where the thickness W1 increases from the peripheral edge 312 side toward the protrusion 34 side.

[0045] In this way, the outer diameter of the liner 3 can be made larger than when the center of the outer diameter is located on the central axis C3. Therefore, if the inner diameter of the liner 3 is the same as in the conventional case, the thickness of the liner 3 can be increased, thereby increasing the strength of the liner 3. Furthermore, if the inner diameter of the liner 3 is made larger than in the conventional case, it becomes possible to place a larger bearing 4 inside the liner 3 than in the conventional case.

[0046] [Embodiment 2] <Configuration of fitting tool 6> As described above, the bearing 4 has a hollow shape with an opening 44, and the femoral head ball 5 is accommodated in the accommodation space 43, allowing the femoral head ball 5 to slide on the inner surface 42 of the bearing 4. Because the diameter of the opening 44 of the bearing 4 is smaller than the diameter of the femoral head ball 5, a strong pushing force is required to accommodate the femoral head ball 5 in the accommodation space 43 of the bearing 4, and a dedicated tool is used. However, depending on the structure of the tool, the pushing part may be pushed back, making it impossible to accommodate the femoral head ball 5 in the accommodation space 43 of the bearing 4.

[0047] The fitting instrument 6 (surgical instrument) according to the second embodiment of the present disclosure has a ratchet structure. The ratchet structure can restrict the movement direction of the pusher portion 64 only to the direction in which the femoral head ball 5 is accommodated in the bearing 4 (the Y1 direction, or first direction, described below). This prevents the pusher portion 64 from being pushed back, allowing the femoral head ball 5 to be efficiently accommodated. Restricting the movement direction of the pusher portion 64 only to the first direction means that a strong force is applied against movement in the direction opposite to the first direction.

[0048] A fitting device 6 according to a second embodiment of the present disclosure will be described below. For convenience of explanation, components having the same functions as those described in the first embodiment will be denoted by the same reference numerals, and the description thereof will not be repeated.

[0049] Fig. 12 is a front view showing an example of the fitting tool 6, and Fig. 13 is a perspective view. In Fig. 12, the bearing 4 and femoral head ball 5 attached to the fitting tool 6 are shown in phantom lines.

[0050] As shown in FIGS. 12 and 13, the fitting device 6 includes a main body portion 61 , a shaft portion 63 , a pushing portion 64 , an operating portion 65 , a fitting portion 66 , and a stopper 67 .

[0051] The main body 61 includes a femoral head ball support 62 (support) that secures the femoral head ball 5. The femoral head ball support 62 has a base 621 and an insertion portion 622 that stands upright from the base 621. As described above, the femoral head ball 5 can be secured to the fitting device 6 by inserting the insertion portion 622 into the recess 53 of the femoral head ball 5.

[0052] The shaft portion 63 is attached to the main body portion 61 so as to be movable in the axial direction by being inserted into an insertion hole 611 formed in the main body portion 61. A plurality of grooves 633 are formed in the axial direction in the shaft portion 63. The shaft portion 63 has a push-in portion 64 attached to a first end portion 631 (first end) and a handle portion 68 attached to a second end portion 632 (second end).

[0053] The push-in portion 64 includes a cup-shaped bearing attachment portion 641. The bearing attachment portion 641 allows the bearing 4 to be attached with the opening 44 of the bearing 4 facing downward (first direction). The bearing attachment portion 641 can be used for alignment when pressing the bearing 4 toward the femoral head ball 5, and can reduce the possibility of misalignment between the bearing 4 and the femoral head ball 5. The push-in portion 64 does not necessarily have to include the bearing attachment portion 641.

[0054] The bearing mounting portion 641 is disposed so as to face the femoral head ball support portion 62. By moving the shaft portion 63 in the axial direction and in a direction approaching the femoral head ball support portion 62 (Y1 direction, first direction), the femoral head ball 5 can be pushed into the accommodation space 43 of the bearing 4 through the opening 44 of the bearing 4.

[0055] The operating unit 65 is a handle-shaped member for operating the fitting tool 6, and includes an operating handle 651 and a fixed handle 652. The operating handle 651 is fixed to the main body 61 so as to be rotatable around a fixed part 6511. As will be described in detail later, a user can move the shaft 63 in the Y1 direction by grasping the operating handle 651 and the fixed handle 652 and rotating the operating handle 651 in a direction approaching the fixed handle 652 (the R1 direction).

[0056] The operating handle 651 is biased in a direction away from the fixed handle 652 (in the R2 direction) by a biasing member such as a spring (not shown), and is configured so that when the user loosens his grip, it rotates in the R2 direction and returns to the position it was in before the user gripped it.

[0057] The fitting portion 66 has a fitting claw 661 that fits into one of the grooves 633 formed in the shaft portion 63, and is fixed to the operating handle 651 by a fixing portion 662. As the operating handle 651 rotates, the fitting portion 66 moves parallel to the Y1 direction while rotating about the fixing portion 662. As will be described in detail later, the rotational movement of the fitting portion 66 causes the fitting claw 661 to press the first surface 634a of the groove 633 in the Y1 direction, allowing the shaft portion 63 to move in the Y1 direction.

[0058] The stopper 67 has a locking claw 671 that fits into one of the grooves 633 formed in the shaft 63, and is fixed to the main body 61 so as to be rotatable around a fixing portion 672. The stopper 67 is biased toward the shaft 63 by a spring 673. When no operation is being performed by the operating portion 65, the locking claw 671 fits into the groove 633, thereby preventing the shaft 63 from being pushed back in the direction opposite to the Y1 direction (Y2 direction).

[0059] The ratchet structure of the fitting device 6 is mainly composed of a stopper 67 and a fitting portion 66. The stopper 67 and the fitting portion 66 will be described in detail later.

[0060] As described above, the handle 68 is attached to the second end 632 of the shaft 63. By turning the handle 68, the user can rotate the shaft 63 about its axis.

[0061] The groove 633 is not formed around the entire circumference of the shaft 63, but is formed only in a portion of the circumference. For example, the groove 633 is formed only in the portion facing the main body 61. Therefore, by turning the handle 68, the user can position the groove 633 on the side opposite to the side facing the main body 61. This allows the engagement of the engagement claw 661 and the locking claw 671 that are engaged with the groove 633 to be released.

[0062] <Ratchet Structure> Fig. 14 is a schematic diagram illustrating the ratchet structure of the fitting device 6. As shown in Fig. 14, the groove portion 633 functions as a ratchet tooth 634 and has a first surface 634a perpendicular to the shaft portion 63 and a second surface 634b oblique to the shaft portion 63.

[0063] The fitting portion 66 is provided with a fitting pawl 661 that meshes with one of the ratchet teeth 634. The stopper 67 is provided with a locking pawl 671 that is biased by a spring 673 toward the ratchet teeth 634 and meshes with the other one of the ratchet teeth 634.

[0064] When the operating handle 651 is operated and rotated in the R1 direction, the fitting portion 66 fixed to the operating handle 651 rotates in the R1 direction around the fixed portion 6511 in accordance with the rotation of the operating handle 651. The fitting pawl 661, while meshed with the ratchet teeth 634, presses the first surface 634a in the Y1 direction, moving the shaft portion 63 in the Y1 direction.

[0065] The fitting portion 66 is biased by a biasing member in a direction diagonally away from the shaft portion 63, on the Y2 side of the fixed portion 662. As a result, once operation using the operating handle 651 is completed, the operating handle 651 is biased in the R2 direction, the fitting claw 661 is biased in the X1 direction, and the entire fitting portion 66 is biased in the Y2 direction. Therefore, the fitting claw 661 slides on the second surface 634b, causing the fitting portion 66 to move in the Y2 direction. Therefore, when the user loosens the operating handle 651, the fitting portion 66 moves in the Y2 direction and returns to its original position.

[0066] On the other hand, the locking claw 671 of the stopper 67 locks the first surface 633a of the ratchet tooth 634 that meshes with the locking claw 671, so that the shaft portion 63 can be prevented from being pushed back and moving in the Y2 direction.

[0067] The shaft 63 can be further moved in the Y1 direction by again operating the operating handle 651. By repeating this operation, the shaft 63 can be moved in the Y1 direction by a desired length.

[0068] This restricts the movement direction of the shaft portion 63 to only the Y1 direction, thereby suppressing push-back and allowing the femoral head ball 5 to be efficiently accommodated in the bearing 4.

[0069] [Summary] A biological implant according to a first aspect of the present disclosure includes an acetabular cup and a liner positioned inside the acetabular cup, the liner having an outer surface that contacts the acetabular cup, the liner being positioned on the periphery of the outer surface and having a first tapered surface that contacts the periphery of the inner surface of the acetabular cup, the first tapered surface having a protrusion. According to the above configuration, the protrusion is disposed on the first tapered surface, thereby increasing the strength of the fit compared to when no protrusion is disposed. Therefore, the strength of the fit between the acetabular cup and the liner can be increased.

[0070] A biological implant according to a second aspect of the present disclosure is the biological implant of the first aspect, further comprising a bearing having an outer surface slidable against the inner surface of the liner. By including the bearing, sliding can be achieved between the outer surface of the bearing and the liner, thereby achieving double sliding, including sliding on the inner surface of the bearing.

[0071] A biological implant according to a third aspect of the present disclosure is the same as that of the first or second aspect, and further includes a femoral head ball that is slidable on the inner surface of the bearing. By including the femoral head ball, sliding can be achieved between the bearing and the femoral head ball.

[0072] The bioimplant according to Aspect 4 of the present disclosure is the bioimplant of Aspect 3, further comprising a stem to be inserted into the femoral head ball. By including the stem, the bioimplant can be properly inserted into the femur.

[0073] A biological implant according to Aspect 5 of the present disclosure is any one of Aspects 1 to 4, wherein the protrusion is formed by arranging a groove on the first tapered surface, and the groove is arranged in a direction different from a line connecting an arbitrary point on the edge of the liner to the zenith. The line connecting an arbitrary point on the edge of the liner to the zenith of the liner is parallel to the mating direction between the acetabular cup and the liner. Therefore, with the above configuration, the groove is arranged in a direction different from the mating direction between the acetabular cup and the liner, and the protrusion formed by the groove is also arranged in a direction different from the mating direction between the acetabular cup and the liner. This increases the mating strength between the acetabular cup and the liner. For example, the groove may be arranged approximately parallel to the edge of the liner.

[0074] A biological implant according to Aspect 6 of the present disclosure is any of Aspects 1 to 4, wherein the protrusion has a shape that protrudes from the first tapered surface toward the acetabular cup, and the protrusion protrudes in a direction different from a line connecting an arbitrary point on the edge of the liner to the zenith vertex, thereby increasing the strength of the fit between the acetabular cup and the liner.

[0075] A biological implant according to Aspect 7 of the present disclosure is any of Aspects 1 to 6, wherein the acetabular cup has a second tapered surface on the periphery of its inner surface, and the first tapered surface and the second tapered surface fit together. According to the above configuration, tapered surfaces are provided on both the acetabular cup and the liner, making it easy to fit the acetabular cup and the liner together.

[0076] A biological implant according to Aspect 8 of the present disclosure is any of Aspects 1 to 7, wherein the liner has a biting portion located on the peripheral side of the first tapered surface and biting into the second tapered surface. According to this configuration, the biting portion increases the resistance to the liner being removed from the acetabular cup, thereby increasing the strength of the fit between the acetabular cup and the liner. The biting portion may be realized by an edge provided by providing a surface on the first tapered surface that forms an angle with the fit direction smaller than the angle of the second tapered surface in a cross section taken along a plane parallel to the fit direction between the acetabular cup and the liner.

[0077] A biological implant according to Aspect 9 of the present disclosure is any of Aspects 1 to 8, wherein when a line passing through the center of the ring formed by the periphery of the liner and parallel to the direction of engagement between the acetabular cup and the liner is taken as a central axis, the liner has a region with a larger thickness in a cross section including the central axis than when the center of the outer shape is set at the central axis. This configuration allows the wall thickness of the liner to be increased, thereby increasing the strength of the liner. Furthermore, by making the inner diameter of the liner larger than conventional, it becomes possible to place a larger bearing inside the liner than conventional.

[0078] A biological implant according to Aspect 10 of the present disclosure is any of Aspects 1 to 9, wherein a central axis is a straight line passing through the center of the periphery of the liner and parallel to the direction of engagement between the acetabular cup and the liner, and when a cross section is taken along a plane passing through the central axis and parallel to the direction of engagement, with one side of the central axis defined as a first side and the other side defined as a second side, the outer shape of the liner on each of the first and second sides has a shape including an arc centered at a point located approximately symmetrically with respect to the central axis. This configuration allows the outer shape of the liner to be larger than when the center of the outer shape is located on the central axis. Therefore, if the inner diameter of the liner is the same as in the conventional case, the thickness of the liner can be increased, thereby increasing the strength of the liner. Furthermore, by increasing the inner diameter of the liner compared to conventional cases, a larger bearing than conventional cases can be placed inside the liner.

[0079] A biological implant according to an eleventh aspect of the present disclosure is any of the first to tenth aspects, wherein when a central axis is a straight line passing through the center of a ring formed by the peripheral edge of the liner and parallel to the fitting direction of the acetabular cup and the liner, the liner has a region in which a cross section including the central axis increases in size from the peripheral edge of the liner toward the apex of the liner. According to the above configuration, the outer shape of the liner can be increased.

[0080] A surgical instrument according to a twelfth aspect of the present disclosure includes a main body having a support portion for supporting a femoral head ball, a pusher portion for pushing the bearing into a hollow bearing having an opening so as to accommodate the femoral head ball, a shank connected to the pusher portion at a first end, and a control portion connected to a side of the shank and for axially moving the shank relative to the main body, wherein the connection between the shank and the control portion is structured such that the shank can be moved axially by the control portion only in a first direction, which is the direction of the first end. With this configuration, because the shank moves only in the first direction, even when a large force is required to accommodate the femoral head ball inside the bearing, the pusher portion can push the bearing in without being pushed back in the direction opposite to the first direction.

[0081] A surgical instrument according to Aspect 13 of the present disclosure is the surgical instrument of Aspect 12, wherein the connection between the shaft portion and the operating portion is a ratchet structure that allows the operating portion to move the shaft in the axial direction only in a first direction, which is the first end direction. With this configuration, the ratchet structure can achieve a structure in which the operating portion allows the shaft portion to move in the axial direction only in the first direction.

[0082] A surgical instrument according to aspect 14 of the present disclosure is the surgical instrument of aspect 12 or 13, wherein a plurality of grooves are arranged in the axial direction on a side surface of the shank, the grooves being formed by a first surface perpendicular to the axis and a second surface oblique to the axis, the operating unit has a fitting portion that fits into one of the plurality of grooves, and the fitting portion is biased in the axial direction to move the shank in the axial direction, the first surface being arranged closer to the first direction than the second surface. With this configuration, a structure in which the shank can be moved only in the first direction by the operating unit can be realized.

[0083] A surgical instrument according to Aspect 15 of the present disclosure is any of Aspects 12 to 14, wherein the main body includes a stopper that is biased toward the shank by an elastic body and fits into the groove. With this configuration, the shank can be prevented from being pushed back in the direction opposite to the first direction when no operation is being performed by the operating unit.

[0084] A surgical instrument according to Aspect 16 of the present disclosure is any of Aspects 12 to 15, further comprising a handle portion at a second end of the shank opposite the first end, the handle portion having a diameter larger than the diameter of the shank. This configuration allows for easy axial rotation of the shank. The groove in the shank is located along a portion of the shank's circumference, allowing for axial rotation of the shank to disengage the operating portion from the groove in the shank and the stopper from the groove in the shank.

[0085] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0086] DESCRIPTION OF SYMBOLS 1 Bioimplant 2 Acetabular cup 21 Outer surface 22 Inner surface 221 Second tapered surface 222 Peripheral edge portion 23 Storage space 24 Insertion hole 3 Liner 31 Outer surface 311 First tapered surface 312 Peripheral edge portion 313 Projection portion 314 Biting portion 32 Inner surface 33 Storage space 34 Projection portion 4 Bearing 41 Outer surface 42 Inner surface 43 Storage space 44 Opening 5 Femoral head ball 51 Outer surface 53 Recessed portion 6 Fitting instrument (surgical instrument) 61 Main body portion 62 Femoral head ball support portion (support portion) 63 Shaft portion 64 Push-in portion 65 Operation portion 67 Stopper 68 Handle portion

Claims

1. A biological implant comprising: an acetabular cup; and a liner positioned inside the acetabular cup, the liner having an outer surface that contacts the acetabular cup, the liner being positioned on the periphery of the outer surface and having a first tapered surface that contacts the periphery of the inner surface of the acetabular cup, the first tapered surface having a protrusion.

2. The bioimplant of claim 1, comprising a bearing having an outer surface that is slidable with the inner surface of the liner.

3. The bioimplant according to claim 2, comprising a femoral head ball slidable on the inner surface of the bearing.

4. The bioimplant according to claim 3, comprising a stem inserted into the femoral head ball.

5. The biological implant according to claim 1, wherein the protrusion is formed by arranging a groove in the first tapered surface, and the groove is arranged in a direction different from a line connecting any point on the edge of the liner to the zenith apex.

6. The biological implant according to claim 1, wherein the protrusion has a shape that protrudes from the first tapered surface toward the acetabular cup, and the protrusion protrudes in a direction different from a line connecting any point on the edge of the liner and the zenith vertex.

7. The biological implant according to claim 1, wherein the acetabular cup has a second tapered surface on the periphery of the inner surface, and the first tapered surface and the second tapered surface are fitted together.

8. The biological implant according to claim 7, wherein the liner is located on the peripheral side of the first tapered surface and has a biting portion that bites into the second tapered surface.

9. The biological implant according to claim 1, wherein, when a straight line passing through the center of the ring formed by the periphery of the liner and parallel to the direction of engagement between the acetabular cup and the liner is taken as the central axis, the liner has a region with a greater thickness in a cross section including the central axis compared to when the center of the outer shape is set at the central axis.

10. The biological implant of claim 1, wherein, when a straight line passing through the center of the periphery of the liner and parallel to the mating direction of the acetabular cup and the liner is taken as the central axis, and when one side of the central axis is taken as the first side and the other side is taken as the second side in a cross section cut along a plane passing through the central axis and parallel to the mating direction, the outer shape of the liner is a shape that includes an arc centered at a point located approximately symmetrically with respect to the central axis on each of the first side and the second side.

11. The biological implant according to claim 1, wherein when a straight line passing through the center of the ring formed by the periphery of the liner and parallel to the direction of engagement between the acetabular cup and the liner is taken as the central axis, the liner has a region in which the cross section including the central axis becomes larger from the periphery of the liner toward the apex of the liner.

12. A surgical instrument comprising: a main body having a support portion that supports a femoral head ball; a pushing portion that pushes a hollow bearing having an opening so as to accommodate the femoral head ball inside the bearing; a shaft that connects to the pushing portion at a first end; and an operating portion that connects to the side of the shaft and moves the shaft in the axial direction relative to the main body, wherein the connection between the shaft and the operating portion is structured so that the axial movement of the shaft by the operating portion is only possible in a first direction, which is the direction of the first end.

13. A surgical instrument as described in claim 12, wherein the connection between the shaft portion and the operating portion is a ratchet structure in which movement of the shaft portion in the axial direction by the operating portion is possible only in a first direction, which is the direction of the first end.

14. A surgical instrument as described in claim 13, wherein a plurality of grooves are arranged in the axial direction on the side of the shaft portion, the grooves being formed by a first surface perpendicular to the shaft and a second surface oblique to the shaft, the operating portion having a fitting portion that fits into one of the plurality of grooves and biasing the fitting portion in the axial direction to move the shaft portion in the axial direction, and the first surface is arranged on the first direction side of the second surface.

15. The surgical instrument according to claim 14, wherein the main body portion has a stopper that is biased against the shaft portion by an elastic body and fits into the groove.

16. The surgical instrument according to claim 12, further comprising a handle portion at a second end of the shank opposite the first end, the handle portion having a diameter larger than the diameter of the shank.

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