Ball trial and surgery instrument system

Abstract

To improve operation of reposition or dislocation.SOLUTION: A ball trial (1) has a substantially spherical segment shape and includes: a slide surface (11) corresponding to a part of a spherical crown of the spherical segment; a cutout surface (12) corresponding to a surface obtained by cutting out a part of the spherical segment in a cross section; and a bottom surface (13) corresponding to at least a part of a surface being a cut area of the spherical segment, the bottom surface (13) being formed with an insertion hole (131) to which a stem of an artificial hip joint or a stem trial for an artificial hip joint is to be inserted.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a ball trial and the like used in surgery to replace part or all of a hip joint with an artificial hip joint. [Background technology]

[0002] In total hip replacement surgery, a ball-shaped artificial hip joint ball trial (hereinafter referred to as ball trial) is used. The ball trial is used to appropriately select the femoral head ball, which is the implant of the artificial hip joint, according to the patient's condition, and multiple reductions and dislocations are often performed.

[0003] In recent years, the use of intermuscular approaches that do not separate the muscles and tendons, such as the Direct Anterior Approach (DAA) and Antero-Lateral Supine Approach (ALS), has been increasing in total hip replacement surgery. Furthermore, large diameter femoral heads are also becoming more widely used.

[0004] When using the intermuscular approach, the tension in the soft tissues around the hip joint cannot be released, making it difficult to reduce or dislocate the ball trial. Also, when using a large-diameter femoral head, the ball diameter becomes larger, making it difficult to reduce or dislocate the ball trial. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2848675 A Summary of the Invention [Problem to be solved by the invention]

[0006] Improve the increasingly difficult task of reducing or dislocating the ball trial. [Means for solving the problem]

[0007] A ball trial according to one embodiment of the present disclosure has an approximately spherical notch shape and includes a first surface corresponding to a portion of the crown of the notch, a second surface corresponding to a surface obtained by cutting off a portion of the notch along a cutting plane, and a third surface corresponding to at least a portion of the surface that is the cut edge of the notch and having an insertion hole formed therein through which the stem of an artificial hip joint or a stem trial for an artificial hip joint is inserted.

[0008] A surgical instrument system according to one aspect of the present disclosure includes the ball trial and a stem or stem trial that mates with the ball trial. Effect of the Invention

[0009] According to one aspect of the present disclosure, reduction or dislocation can be performed more easily than with a conventional ball trial that does not have a second surface. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an overview of an artificial hip joint. [Diagram 2] 1A and 1B are diagrams showing the external shape of a ball trial according to a first embodiment of the present disclosure. [Diagram 3] 1A to 1C are diagrams showing an example of the shape of a ball trial. [Figure 4] FIG. 1 is a diagram showing an overall overview of a ball trial. [Diagram 5] FIG. 2 is a cross-sectional view showing a cross section of a ball trial. [Figure 6] FIG. 1 is a diagram showing a conventional ball trial. [Figure 7] 1 is a diagram showing a difference between a ball trial according to the first embodiment and a conventional ball trial. [Figure 8] 1 is a diagram showing a difference between a ball trial according to the first embodiment and a conventional ball trial. [Figure 9] 1A to 1C are diagrams showing the flow of dislocation and reduction of a ball trial according to embodiment 1. [Figure 10]1A to 1C are diagrams showing the procedure for dislocation and reduction of a conventional ball trial. [Figure 11] 1 is a diagram showing a difference between a ball trial according to the first embodiment and a conventional ball trial. [Figure 12] FIG. 13 is a diagram showing an overall overview of a ball trial according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment 1] Hereinafter, one embodiment of the present disclosure will be described in detail.

[0012] [Overview of artificial hip joints] First, before describing the ball trial 1 according to this embodiment, an artificial hip joint that is replaced with a hip joint by total hip joint replacement surgery using the ball trial 1 will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of an artificial hip joint.

[0013] As shown in Fig. 1, the artificial hip joint 100 includes a stem 103, a femoral head ball 104, and a cup 105. The stem 103 is an axial member, and a portion of it is inserted into the medullary cavity of the femur 101 to form a femoral component. A neck portion that protrudes from the femur 101 is provided at the end of the stem 103 opposite to the side that is inserted into the femur 101. The neck portion is provided with a tapered portion that is formed obliquely in the direction that it protrudes from the femur 101, in other words, with respect to the direction in which the side surface is inserted into the cup 105.

[0014] The femoral head ball 104 is configured as a spherically formed component. An insertion hole into which the neck portion of the stem 103 is inserted is provided in the femoral head ball 104, and the femoral head ball 104 is fixed to the stem 103 by inserting the stem 103 into the femoral head ball 104 and fitting them together.

[0015] The cup 105 is fixed to the pelvis 102. The cup 105 is arranged so that the femoral head ball 104 slides on the inner surface of the cup 105. The cup 105 may have a liner (not shown) on its inner surface, and may be arranged so that the femoral head ball 104 slides on the inner surface of the liner.

[0016] The ball trial 1 is used by the surgeon to select a femoral head ball 104 that can be appropriately set at the time of performing total hip arthroplasty. The offset indicates the positional relationship of the femoral head ball 104 with respect to the neck portion of the stem 103.

[0017] The ball trial 1 is slidably housed in the cup 105 and is detachably attached to the neck portion of the stem 103. The ball trial 1 is used by the surgeon by repeatedly attaching it to the neck portion and removing it from the neck portion as appropriate. In detail, the surgeon attaches the ball trial 1 to the stem 103 and checks the range of motion of the artificial hip joint, the resistance to dislocation, and the tension generated by the soft tissue between the femur 101 and the pelvis 102. Then, the surgeon replaces the ball trial 1 with another ball trial 1 having a different size and offset and performs the same operation to consider the appropriate size and offset. Then, the femoral head ball 104 corresponding to the ball trial 1 determined to be appropriate is selected.

[0018] Furthermore, the surgical instrument system may include the ball trial 1 and the stem 103 or stem trial (not shown) attached to the ball trial 1. The surgical instrument system may also include a cup 105 or a cup trial (not shown).

[0019] [Ball trial details] Next, the ball trial 1 will be described in detail with reference to Figs. 2 to 5. Fig. 2 is a diagram for explaining the external shape of the ball trial 1. As shown in Fig. 2, the ball trial 1 has a substantially spherical notch shape. The ball trial 1 has a sliding surface 11 (first surface) corresponding to a part of the spherical crown of the notch, a cut surface 12 (second surface) corresponding to a surface obtained by cutting away a part of the notch by a cutting surface, and a bottom surface 13 (third surface) corresponding to at least a part of the surface that becomes the cut end of the notch. The cut surface 12 and the bottom surface 13 share a first side 121.

[0020] The sliding surface 11 corresponds to a part of the spherical crown of the notch, meaning that when a notch that is the original shape of a substantially notch is assumed, a part of the spherical crown of the notch is the sliding surface 11. However, the curvature of the spherical crown of the notch does not have to match the curvature of the sliding surface 11. In other words, the sliding surface 11 does not have to be a part of the spherical surface of a perfect sphere with a constant curvature.

[0021] The cut-out surface 12 corresponds to a surface obtained by cutting a part of a spherical notch by a cutting plane, meaning that, assuming a spherical notch having an original shape of a roughly spherical notch, a surface obtained by cutting a part of the spherical notch by a cutting plane is the cut-out surface 12. However, the cut-out surface 12 does not have to be entirely flat. Also, the cut-out surface 12 may be only a part of the cut surface, not the entire cut surface.

[0022] The bottom surface 13 corresponds to at least a part of the surface that is the cut end of the spherical notch, meaning that when a spherical notch that is the original shape of a roughly spherical notch is imagined, at least a part of the surface that is the cut end of the spherical notch is the bottom surface 13. However, the bottom surface 13 does not have to be entirely flat. Also, the bottom surface 13 may be only a part of the surface that is the cut end, not the entire surface.

[0023] A sphere is a solid object that is created when a sphere is cut by a plane. A crown is the side (spherical) part of a sphere. In other words, a crown is a part of a sphere cut by a plane that intersects with it, and a sphere is a solid object enclosed by the crown and the plane.

[0024] In addition, the ball trial 1 being substantially spherically deficient includes, for example, the following shapes. The sphere that is the source of the spherically deficient is not limited to a complete sphere. In other words, the substantially spherically deficient shape is not limited to a part of a complete sphere. Also, a part of the spherically deficient may include a straight line or a flat surface. Also, a part of the spherically deficient may be missing. Also, a part of the spherically deficient may have a hole. Also, the curvature of the curved surface of the spherically deficient may not be constant, and the curvature may change in part. The substantially spherically deficient ball trial 1 may have a curved surface that can slide against the inner surface of the cup 105 or the cup trial. The substantially spherically deficient shape may be a curved surface obtained by cutting out the sphere.

[0025] That is, the ball trial 1 has a first surface which is a part of the crown of the notch, a second surface which is a cut surface of a part of the notch, and a third surface which is a cut edge of the notch. Since the second surface is a surface where a part of the notch is cut off by a cut surface, the distance from the center position of the ball trial is shorter than that of the first surface which is a part of the crown. Therefore, the reduction or dislocation of the ball trial can be performed at a position closer to the cup by the shortened distance. This makes it easier to perform reduction or dislocation compared to a conventional ball trial that does not have a second surface.

[0026] In this embodiment, an example in which there is one cut-out surface 12 will be described, but there may be two or more cut-out surfaces 12. When the ball trial 1 has two or more cut-out surfaces 12, reduction or dislocation can be easily performed in two or more directions. For example, the ball trial 1 may have two cut-out surfaces 12. The two cut-out surfaces 12 may be located on opposite sides of the center of the ball trial 1. The two cut-out surfaces 12 may also be located next to each other.

[0027] The sliding surface 11 is a surface that slidably contacts the inner surface of the cup 105 of the artificial hip joint 100. The sliding surface 11 includes a distal point from the bottom surface 13 of the ball crown. By including the distal point from the bottom surface 13, the cutout surface 12 can be provided without impairing the function of the ball trial 1.

[0028] The cut surface 12 is substantially flat. The cut surface 12 may be curved or uneven. On the radius of the outer periphery of the spherical cut that is perpendicular to the first side 121 of the cut surface 12, the distance d between the first side 121 and the outer periphery of the cut is, for example, 5 mm or more.

[0029] The bottom surface 13 is a surface that is the cut end of the spherical notch, excluding the portion cut away by the cut surface. A part of the bottom surface 13 is substantially flat. A part of the bottom surface 13 may be curved or uneven.

[0030] The bottom surface 13 may be provided with an indicator (not shown) indicating the position of the cutout surface 12. The ball trial 1 is in the patient's wound during treatment and may be difficult for the surgeon to see. If an indicator is provided on the bottom surface 13 at a position visible to the surgeon during treatment, the surgeon can easily recognize the position of the cutout surface 12 at the time of reduction or dislocation. When the ball trial 1 is made of a resin material, for example, only the indicator may have a color different from the surrounding color. When the ball trial 1 is made of a metal material, for example, the indicator may be printed by a laser.

[0031] Hereinafter, the direction perpendicular to the bottom surface 13 of the ball trial 1 corresponding to the cut end of the ball notch will be referred to as the z direction, the direction parallel to the bottom surface 13 and perpendicular to the first side 121 as the x direction, and the direction parallel to the first side 121 as the y direction.

[0032] Fig. 2 shows a schematic diagram of the shape of the ball trial 1. In Fig. 2, the corners where the faces of the ball trial 1 intersect are angular, but the corners may be chamfered. Fig. 3 shows an example in which the corners where the faces of the ball trial 1 intersect are chamfered. In Fig. 3, 301 is a perspective view of the ball trial 1, 302 is a view of the ball trial 1 as viewed from the y direction, and 303 is a view of the ball trial 1 as viewed from the x direction.

[0033] 3, a chamfer 113 may be applied to the corner where the sliding surface 11 and the cut-out surface 12 intersect, a chamfer 111 may be applied to the corner where the sliding surface 11 and the bottom surface 13 intersect, and a chamfer 112 may be applied to the corner where the cut-out surface 12 and the bottom surface 13 intersect. In addition, the chamfered surface is not limited to a flat surface, and may be a curved surface.

[0034] Fig. 4 is a diagram showing an overall outline of the ball trial 1. Reference numeral 401 in Fig. 4 is a perspective view of the ball trial 1 seen from the z direction, and reference numeral 402 in Fig. 4 is a perspective view of the ball trial 1 seen from the -z direction. As shown in Fig. 4, the ball trial 1 has an insertion hole 131 in the bottom surface 13. The insertion hole 131 is a hole into which the stem 103 of the artificial hip joint 100 or the neck portion of a stem trial for an artificial hip joint (not shown) is inserted.

[0035] 5 shows a cross section of the ball trial 1 taken along the line IV-IV shown in 401 of FIG. 4. As shown in 501 of FIG. 5, the cut surface 12 is approximately parallel to the axial direction of the insertion hole 131. 5 of FIG. 5 shows a state in which the neck portion of the stem 103 is inserted into the insertion hole 131. As shown in 502 of FIG. 5, the length LB of the insertion hole 131 in the axial direction (insertion direction) is shorter than the length LS of the tapered portion 103b provided in the neck portion of the stem 103 in the axial direction.

[0036] [Comparison with conventional technology] Next, differences between the ball trial 1 of the present disclosure and a conventional ball trial 2 will be described with reference to Figs. 6 to 8. Fig. 6 is a diagram showing a conventional ball trial 2. 6 in Fig. 6 is a perspective view of the ball trial 2, and 602 in Fig. 6 is a cross-sectional view of the ball trial 2 taken along line VI-VI shown in 601. As shown in 601 in Fig. 6, the ball trial 2 is substantially spherically recessed, and includes a sliding surface 21 and a bottom surface 23. An insertion hole 231 into which the stem 103 or stem trial is inserted is formed in the bottom surface 23.

[0037] 7 and 8 are diagrams comparing the cross sections of ball trial 1 and ball trial 2. As shown in Fig. 7, ball trial 1 has a cutout surface 12, and therefore the length in the x direction is shorter by Wd than ball trial 2. Also, as shown in Fig. 8, the length in the z direction of ball trial 1 is shorter by Hd than ball trial 2.

[0038] [Effects of using Ball Trial 1] Next, the effects of using the ball trial 1 will be described with reference to Figures 9 to 11. Figure 9 shows the flow of reduction and dislocation of the ball trial 1. Figure 10 shows the flow of reduction and dislocation of a conventional ball trial 2.

[0039] 901 in Fig. 9 shows a state in which the ball trial 1 is housed in the inner surface of the cup 105. When dislocating the ball trial 1 from this state, the ball trial 1 is removed while sliding along the inner surface of the cup 105 as shown in 901 → 902 → 9 → 904 in Fig. 9. Conversely, when reducing the ball trial 1, the ball trial 1 is moved from the outside of the cup 105 to the inner surface along the edge of the cup 105 as shown in 9 → 903 → 902 → 9 in Fig. 9, and then attached by moving the ball trial 1 along the inner surface of the cup 105.

[0040] Therefore, in both dislocation and reduction, a space is required in the direction away from the edge of the cup 105, that is, the length of the bottom surface 13 of the ball trial 1, i.e., the length RA shown by 904 in FIG.

[0041] Even in the case of a conventional ball trial 2 having the same size as the ball trial 1, the flow of dislocation and reduction is the same as that of the ball trial 1. That is, as shown in FIG. 10, when dislocating the ball trial 2, the ball trial 2 is removed while sliding along the inner surface of the cup 105 as shown by 1001, 1002, 1003, and 1004 in FIG. 10. When reducing the ball trial 2, the ball trial 2 is moved from the outside of the cup 105 to the inner surface along the edge of the cup 105 as shown by 1004, 1003, 1002, and 1001 in FIG. 10, and then moved along the inner surface of the cup 105 to attach it. Therefore, in both dislocation and reduction, a space is required in the direction away from the edge of the cup 105 by the length of the bottom surface 23 of the ball trial 2, i.e., the length RB shown by 1004 in FIG. 10.

[0042] As described above, when dislocating or reducing the ball trial 1, a space of length RA is required in a direction away from the edge of the cup 105, and when dislocating or reducing the conventional ball trial 2, a space of length RB is required in a direction away from the edge of the cup 105. As described above, RA is shorter than RB by Wd. Therefore, with the ball trial 1, reduction or dislocation can be performed in a smaller space than with the conventional ball trial 2.

[0043] In other words, the cut-out surface 12 is a substantially planar surface formed by cutting away a portion of the notch, and therefore the distance from the center position of the ball trial 1 is shorter than that of the sliding surface 11, which is a portion of the spherical crown. This shortened distance allows reduction or dislocation of the ball trial 1 to be performed at a position closer to the cup 105. This allows for easier reduction or dislocation compared to a conventional ball trial 2 that does not have a cut-out surface 12.

[0044] Next, referring to FIG. 11, the case of removing the stem 103 from the bolt trial 1 or the bolt trial 2 will be described. FIG. 11 is a diagram showing the flow of removing the stem 103 from the bolt trial 1 and the bolt trial 2.

[0045] 1101 in FIG. 11 shows a state where the stem 103 is inserted into the bolt trial 1, and 1102 shows a state where the stem 103 is removed from the bolt trial 1. Also, 1103 in FIG. 11 shows a state where the stem 103 is inserted into the bolt trial 2, and 1104 shows a state where the stem 103 is removed from the bolt trial 2.

[0046] As shown in 1101 and 1102 of FIG. 11, when removing the stem 103 from the bolt trial 1, it is necessary to pull the stem 103 by a length LB in the axial direction of the insertion hole 131 in a direction away from the bolt trial 1.

[0047] On the other hand, when removing the stem 103 from the bolt trial 2, as shown in 1103 and 1104 of FIG. 11, it is necessary to pull the stem 103 by a length SB in the axial direction of the insertion hole 231 in a direction away from the bolt trial 1.

[0048] The axial length LB of the insertion hole 131 of the bolt trial 1 is shorter than the axial length LS of the tapered portion 103b provided in the neck portion of the stem 103. On the other hand, the axial length SB of the insertion hole 231 of the bolt trial 2 is longer than the axial length LS of the tapered portion 103b provided in the neck portion of the stem 103. That is, LB < LS < SB. Therefore, by using the bolt trial 1, the bolt trial 1 can be removed from the stem 103 with a shorter length than when using the conventional bolt trial 2. That is, the stem 103 can be removed from the bolt trial 1 more easily than before.

[0049] As described above, the bolt trial 1 according to the present embodiment has the following two configurations. (1) A cut surface 12 is provided. (2) The axial length LB of the insertion hole 131 is shorter than the axial length LS of the tapered portion 103 b provided at the neck portion of the stem 103 . The ball trial 1 is not limited to this configuration, and may be configured to have, for example, only the above (1) or only (2).

[0050] The insertion hole 131 may be provided with a sleeve (not shown) for fixing the stem 103 to its inner surface. The axial length of the sleeve is shorter than the axial length of the insertion hole 131. When the sleeve is provided, the through hole 122 described below is not provided in the sleeve.

[0051] [Embodiment 2] Other embodiments of the present disclosure will be described below. For convenience of explanation, the same reference numerals will be given to components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0052] The ball trial 1 ′ according to this embodiment differs from the above-described ball trial 1 in that a through hole 122 that penetrates the insertion hole 131 is provided in the cutout surface 12 .

[0053] Fig. 12 shows an overview of a ball trial 1' according to this embodiment. Reference numeral 1201 in Fig. 12 shows a perspective view of the ball trial 1', and reference numeral 1202 shows a cross section taken along line XII-XII shown in 1201. As shown in Fig. 12, the ball trial 1' has a through hole 122 that penetrates the insertion hole 131 on the cut surface 12.

[0054] During reduction or dislocation, the ball trial 1' may come off the stem 103. In this case, it is necessary to retrieve the ball trial 1' from within the wound, but in the case of DAA and ALS, the skin incision is small, so retrieval may not be easy.

[0055] Therefore, if a through hole 122 is provided in the cutout surface 12 and a string is threaded through this through hole 122, the ball trial 1' can be easily retrieved by pulling in the string.

[0056] It is possible to provide a through hole in the sliding surface 21 even in the conventional ball trial 2. However, if a through hole is provided in the sliding surface 21 and a thread is passed through it, the thread may get between the sliding surface 21 and the inner surface of the cup 105, and the inner surface of the cup 105 and the sliding surface 21 may be damaged.

[0057] By providing a through hole 122 in the cutout surface 12 as in the ball trial 1', the cutout surface 12 does not come into contact with the inner surface of the cup 105, thereby reducing the possibility that the thread passing through the through hole 122 will come into contact with the inner surface of the cup 105 and the sliding surface 11 and damage them.

[0058] [Method of manufacturing ball trial] The ball trial 1 may be molded, for example, from a metal or from a resin. Examples of metal include stainless steel and titanium alloys. When molded from a metal, the ball trial 1 is molded, for example, by cutting or die casting.

[0059] When the ball trial 1 is made of resin, the ball trial 1 is molded by, for example, cutting and injection molding. Examples of the resin include polyphenylsulfone, polyacetal, and polypropylene.

[0060] 〔summary〕 The ball trial according to aspect 1 of the present disclosure has a generally spherical notch shape and includes a first surface corresponding to a portion of the crown of the notch, a second surface corresponding to a surface obtained by cutting a portion of the notch along a cutting surface, and a third surface corresponding to at least a portion of the surface that is the cut end of the notch and having an insertion hole formed therein through which the stem of an artificial hip joint or a stem trial for an artificial hip joint is inserted.

[0061] Reduction or dislocation of the ball trial is performed to a position where the bearing surface is either rubbing or not rubbing against the rim of the cup in which the ball trial is received.

[0062] According to the above-mentioned configuration, since the second surface is a surface in which a part of the notch is cut off by a cutting surface, the distance from the center position of the ball trial is shorter than that of the first surface, which is a part of the ball crown. The ball trial can be reduced or dislocated at a position closer to the cup by the shortened distance. This makes it easier to reduce or dislocate the ball trial compared to a conventional ball trial that does not have a second surface.

[0063] A ball trial according to aspect 2 of the present disclosure is the same as aspect 1, except that the first surface is a sliding surface that slidably contacts the inner surface of the cup of an artificial hip joint. By making the first surface a sliding surface that slides against the inner surface of the cup of an artificial hip joint, the ball trial can properly function as a ball trial.

[0064] In a ball trial according to an aspect 3 of the present disclosure, in the above-described aspects 1 or 2, the second surface is substantially planar. Since the second surface is substantially planar, the surgeon can easily perform a reduction or dislocation operation.

[0065] A ball trial according to an aspect 4 of the present disclosure is any one of the aspects 1 to 3, wherein the second surface is substantially parallel to the axial direction of the insertion hole. With this configuration, reduction or dislocation can be easily performed in the axial direction of the insertion hole.

[0066] A ball trial according to a fifth aspect of the present disclosure is any one of the first to fourth aspects, wherein the first surface includes a distal point of the spherical crown from the third surface. According to the above configuration, since the first surface includes a distal point of the spherical crown from the third surface, the second surface can be provided without impairing the function of the ball trial.

[0067] A ball trial according to a sixth aspect of the present disclosure is any one of the first to fifth aspects, wherein the second and third surfaces share a first side between an outer periphery of the cut end of the ball notch and the insertion hole. This configuration reduces the risk that the second surface will interfere with the insertion hole and affect the fit between the ball trial and the stem or stem trial.

[0068] A ball trial according to a seventh aspect of the present disclosure is the same as in the sixth aspect, except that the distance between the first side and the outer periphery is 5 mm or more on the radius of the outer periphery of the cut edge of the ball notch that is perpendicular to the first side. According to the above configuration, the distance between the first side and the outer periphery of the surface that becomes the cut edge of the ball notch is 5 mm or more, so that reduction or dislocation can be performed at a position 5 mm or more closer to the cup than in the conventional ball trial.

[0069] A ball trial according to aspect 8 of the present disclosure is any one of aspects 1 to 7, wherein the length of the insertion hole in the insertion direction is shorter than the length of the tapered portion provided on the stem or the neck portion of the stem trial in the insertion direction.

[0070] According to the above configuration, the length in the insertion direction of the insertion hole into which the neck portion of the stem or stem trial is inserted is shorter than that of a conventional ball trial, making it easy to attach and remove the ball trial from the stem or stem trial.

[0071] The ball trial according to a ninth aspect of the present disclosure is any one of the first to eighth aspects, further including a through hole that passes through the second surface and the insertion hole.

[0072] In the past, holes were drilled in the ball trial and a thread was threaded through it, and the thread was used to retrieve the stem or the ball trial that had come off the stem trial from within the wound. In this case, the thread could get caught between the inner surface of the cup and the outer surface of the ball trial, damaging both.

[0073] According to the above-mentioned configuration, a through hole is provided between the second surface and the insertion hole. Since the second surface does not contact the inner peripheral surface of the cup, even if the thread is threaded through the through hole provided in the second surface, the thread will not be pinched between the inner peripheral surface of the cup and the outer peripheral surface of the ball trial. Therefore, the risk of damaging the inner peripheral surface of the cup and the outer peripheral surface of the ball trial can be reduced.

[0074] A ball trial according to a tenth aspect of the present disclosure is any one of the first to ninth aspects, further comprising an indicator on the third surface that indicates the position of the second surface. With this configuration, the surgeon can easily recognize the position of the second surface during reduction or dislocation.

[0075] A ball trial according to an eleventh aspect of the present disclosure is any one of the first to tenth aspects, wherein a plurality of the second surfaces are provided. With this configuration, it becomes easy to make the second surface face the cup side during reduction or dislocation, so that reduction or dislocation can be performed more easily.

[0076] A surgical instrument system according to a twelfth aspect of the present disclosure includes the ball trial and a stem or stem trial that fits with the ball trial. A surgical instrument system including a ball trial that can easily perform reduction or dislocation can be realized.

[0077] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0078] 1. Ball Trial 11 Sliding surface (first surface) 12 Cutting surface (2nd side) 121 Side 1 122 Through hole 13 Bottom (3rd side) 131 Insertion hole 2. Conventional ball trial 21 Sliding surface 23 Bottom 100 Artificial Hip Joint 101 Femur 102 Pelvis 103 Stem 104 Head Ball 105 Cups

Claims

1. It has a substantially spherical shape, a first surface corresponding to a portion of the crown of the globular cavity; A second surface corresponding to a surface obtained by cutting a portion of the recess by a cutting surface; A ball trial having a third surface corresponding to at least a portion of the surface that becomes the cut end of the ball notch and having an insertion hole formed therein into which a stem of an artificial hip joint or a stem trial for an artificial hip joint is inserted.

2. The ball trial according to claim 1 , wherein the first surface is a sliding surface that slidably contacts an inner surface of a cup of an artificial hip joint.

3. The ball trial of claim 1 , wherein the second surface is generally planar.

4. The ball trial of claim 1 , wherein the second surface is substantially parallel to an axial direction of the insertion hole.

5. The ball trial of claim 1 , wherein the first surface includes a point at the crown distal from the third surface.

6. The ball trial of claim 1 , wherein the second surface and the third surface share a first side between an outer periphery of the cut end of the ball notch and the insertion hole.

7. The ball trial of claim 6 , wherein the distance between the first side and the outer periphery on the radius of the outer periphery circle of the cut end of the ball notch that is perpendicular to the first side is 5 mm or more.

8. The ball trial according to claim 1 , wherein a length of the insertion hole in the insertion direction is shorter than a length of a tapered portion located in a neck portion of the stem or the stem trial in the insertion direction.

9. The ball trial of claim 1 , further comprising a through hole extending through the second surface and the insertion hole.

10. The ball trial of claim 1 , further comprising an indicator on the third surface that indicates a position of the second surface.

11. The ball trial of claim 1 having a plurality of said second surfaces.

12. A ball trial according to any one of claims 1 to 11; a stem or stem trial that mates with the ball trial.

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