Bone cutting support jig

Abstract

This invention provides an osteotomy support jig that allows for easy protection of surrounding tissues and guidance of osteotomy instruments during osteotomy, enabling safe, accurate, and easy osteotomy regardless of the surgeon's skill level. [Solution] The bone cutting support jig is used for bone cutting of long bones and comprises a retractor body that extends in the longitudinal direction and has a bone contact portion at the end in the longitudinal direction, the bone contact portion has a bone contact surface on one side in the thickness direction that can contact the long bone, and the retractor body has a guide groove formed along the longitudinal direction along the entire length on the same side as the bone contact surface.

Description

Technical Field

[0001] The present invention relates to a bone cutting assist tool used for bone cutting of long bones.

Background Art

[0002] In the treatment of osteoarthritis, fracture deformity healing, and congenital bone morphological abnormalities, bone cutting of long bones is performed. The long bones to be cut are, for example, the tibia, femur, humerus, and forearm bone. Usually, a part of the long bone is excised using a bone cutting instrument such as a bone saw or a bone chisel. For example, a plurality of guide pins (K wires) for defining a bone cutting surface are inserted into the long bone, and bone cutting is performed by advancing a bone cutting instrument along these guide pins.

[0003] Also, when performing bone cutting using a bone cutting instrument or the like, the surrounding tissue is protected by a retractor having a flat spatula shape. Specifically, the retractor is inserted between the bone cutting instrument and the incision site, and is set up so that the cutting edge of the bone cutting instrument abuts on the flat surface of the retractor, thereby preventing accidental incision or damage to the surrounding tissue by the bone cutting instrument.

[0004] Also, various guide tools for facilitating bone cutting along guide pins have been proposed (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, conventionally, since the retractor and guide jig are made of separate components, a certain level of skill and experience is required to perform osteotomy using the guide jig while protecting the surrounding tissue with the retractor. In particular, it was difficult for inexperienced surgeons unfamiliar with osteotomy to perform it safely and accurately.

[0007] The objective of the present invention is to provide an osteotomy support jig that can easily protect surrounding tissues and guide the osteotomy instrument during osteotomy, enabling safe and accurate osteotomy regardless of the surgeon's skill level. [Means for solving the problem]

[0008] The bone cutting support jig according to the present invention is A bone cutting support jig used for osteotomy of long bones, The retractor body extends in the longitudinal direction and has bone contact portions at its ends in the longitudinal direction, The bone contact portion has a bone contact surface on one side in the thickness direction that can contact the long bone, The retractor body has a guide groove formed along its entire length in the longitudinal direction on the same side as the bone contact surface. [Effects of the Invention]

[0009] According to the present invention, during osteotomy, protection of surrounding tissues and guidance of the osteotomy instrument can be easily achieved, and osteotomy can be performed safely, accurately, and easily, regardless of the surgeon's skill level. [Brief explanation of the drawing]

[0010] [Figure 1] Figures 1A and 1B are external perspective views of the bone cutting support jig according to the first embodiment. [Figure 2] Figure 2 is an exploded perspective view of the bone cutting support jig. [Figure 3] Figures 3A to 3D are schematic perspective views illustrating the installation method of the osteotomy support jig. [Figure 4]Figures 4A to 4D are schematic side views illustrating the installation method of the osteotomy support jig. [Figure 5] Figures 5A and 5B show examples of how the bone cutting support jig is installed. [Figure 6] Figures 6A and 6B are external perspective views of the bone cutting support jig according to the second embodiment. [Figure 7] Figure 7 is an exploded perspective view of the bone cutting support jig. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] [First Embodiment] Figures 1A and 1B are external perspective views of the osteotomy support jig 1 according to the first embodiment of the present invention. Figure 2 is an exploded perspective view of the osteotomy support jig 1. The osteotomy support jig 1 is a jig used for osteotomy of long bones. Long bones that are the target of osteotomy include, for example, the tibia, femur, humerus, and forearm bones.

[0013] This specification uses a Cartesian coordinate system (X, Y, Z). In Figure 1A, etc., the X-axis direction is the longitudinal direction of the retractor body 10. The Y-axis direction is the width direction of the retractor body 10. The Z-axis direction is the thickness direction of the retractor body 10. For convenience, the positive side of the Z-axis direction is referred to as the "upper side" and the negative side as the "lower side".

[0014] As shown in Figure 1A, the bone cutting support jig 1 includes a retractor body 10. In addition to the retractor body 10, the bone cutting support jig 1 also includes a first auxiliary member 20 and a second auxiliary member 30.

[0015] The retractor body 10 is a main component of the bone cutting support jig 1. The retractor body 10 can independently protect the surrounding tissue of the bone cutting site and guide the bone cutting instrument (e.g., bone saw).

[0016] The retractor body 10 is a rod-shaped or plate-shaped member extending in the longitudinal direction (X-axis direction). The width of the retractor body 10 (excluding the wing part 14) is, for example, constant over the entire length. The dimensions of the retractor body 10 are appropriately set according to the long bone to be osteotomized. Typically, the length is 50 - 300 mm, the width is 2 - 15 mm, and the thickness is 2 - 20 mm. As an example, when the bone cutting assist tool 1 is used for tibial osteotomy, the dimensions of the retractor body 10 are a length of 200 mm, a width of 10 mm, and a thickness of 10 mm. The retractor body 10 is formed of an X-ray transmissive metal such as titanium, for example.

[0017] The retractor body 10 has a body part 11 and a bone contact part 12. The body part 11 has a flat plate shape. The bone contact part 12 has a curved shape with a predetermined thickness. The bone contact part 12 is arranged at the end of the retractor body 10 in the longitudinal direction. The bone contact part 12 is inserted into the incision site during osteotomy.

[0018] The bone contact part 12 has, for example, a spatula shape with a thickness that decreases towards the tip. The upper surface 12a of the bone contact part 12 contacts the tibia during osteotomy (hereinafter referred to as the "bone contact surface 12a"). The bone contact surface 12a has a curved surface shape that can contact the tibia. On one side in the width direction of the bone contact part 12 (for example, the proximal end side in the Y-axis direction), a recess 12b that can fit the tibia is formed.

[0019] The retractor body 10 has a guide groove 13 on the same side as the bone contact surface 12a. The guide groove 13 guides the progress of the cutting edge of the osteotomy instrument during osteotomy. The guide groove 13 is formed along the longitudinal direction over the entire length at the center in the width direction of the retractor body 10. The guide groove 13 does not penetrate the retractor body 10 in the thickness direction. When the retractor body 10 is formed of an X-ray transmissive metal, the guide groove 13 is also drawn in the X-ray image together with the overall image of the retractor body 10.

[0020] The width of the guide groove 13 is approximately the same as the blade of the bone cutting instrument (for example, 3 mm). The depth of the guide groove 13 should be sufficient to guide the bone cutting instrument in a stable position without it falling off due to vibrations during bone cutting (for example, 8 mm).

[0021] The retractor body 10 has wing portions 14 formed on the upper part of the fuselage portion 11 so as to protrude on both sides in the width direction (Y-axis direction). The wing portions 14 have a flat plate shape and can engage with the retractor connection portion 31 of the second auxiliary member 30.

[0022] In this embodiment, the retractor body 10 has a structure that is symmetrical in the longitudinal direction (X-axis direction). Specifically, bone contact portions 121 and 122 are provided in series at both ends of the torso portion 11 in the longitudinal direction. In addition, each of the bone contact portions 121 and 122 has a recess 12b formed on the same side in the width direction that can conform to the shape of the tibia.

[0023] The bone contact parts 121 and 122 are used differently depending on the method of use during osteotomy. Specifically, the bone contact parts 121 and 122 to be used are determined depending on whether the target of the osteotomy is the right tibia or the left tibia, and whether the incision is made from the medial side (closer to the midline) or the lateral side.

[0024] The first auxiliary member 20 and the second auxiliary member 30 are auxiliary members for holding the bone cutting instrument in a stable position during bone cutting. The first auxiliary member 20 and the second auxiliary member 30 are detachable from the retractor body 10.

[0025] The first auxiliary member 20 is a member that extends in the longitudinal direction and has a flat plate shape overall. The length of the first auxiliary member 20 is, for example, about the same as the body portion 11 of the retractor body 10. The first auxiliary member 20 is attached to the retractor body 10 via the second auxiliary member 30.

[0026] The first auxiliary member 20 has a guide pin holding portion 21 and a posture fixing portion 22. The guide pin holding portion 21 is located at one end of the first auxiliary member 20 in the longitudinal direction. The posture fixing portion 22 is located at the other end of the first auxiliary member 20 in the longitudinal direction. Since the guide pin holding portion 21 is located at a certain distance from the osteotomy portion, it is less likely to interfere with the osteotomy instrument S and does not hinder the adjustment of the position and angle of the osteotomy instrument S.

[0027] The guide pin holder 21 holds a plurality of guide pins that define the bone cutting surface. The guide pin holder 21 has a plurality of insertion holes 23 through which the plurality of guide pins can be individually inserted. In this embodiment, the guide pin holder 21 is provided with two insertion holes 231 and 232.

[0028] The cross-sectional shape of one through hole 231 is circular to match the outer shape of the guide pin. The cross-sectional shape of the other through hole 232 is rectangular or oval. Even if the distance between the first guide pin K1 inserted into the through hole 231 and the guide pin K2 inserted into the through hole 232 is not constant, multiple guide pins K1 and K2 can be inserted into and held in the through holes 231 and 232.

[0029] Guide pins K1 and K2, inserted through the through holes 231 and 232, are positioned so as to be exposed along the guide surface 24 of the first auxiliary member 20. Grooves communicating with the through holes 231 and 232 may be formed on the guide surface 24.

[0030] The posture fixing part 22 fixes the relative posture between the retractor body 10 and the first auxiliary member 20. The posture fixing part 22 is engageable with the second auxiliary member 30. In this embodiment, the posture fixing part 22 has a slit 25 that can engage with the upright walls 321 and 322 of the second auxiliary member 30.

[0031] The second auxiliary member 30 is a member that connects the retractor body 10 and the first auxiliary member. The second auxiliary member 30 has a retractor connection portion 31 and an auxiliary member connection portion 32. The retractor connection portion 31 is the part that is connected to the retractor body 10. The auxiliary member connection portion 32 is the part that is connected to the first auxiliary member 20.

[0032] The second auxiliary member 30 is integrally formed by combining multiple plates so as to have a hollow portion 33. The hollow portion 33 has a cross shape when viewed from the X-axis direction.

[0033] The retractor connection portion 31 is formed to protrude from both sides in the width direction (Y-axis direction). The retractor connection portion 31 has a recess 311 formed from a part of the hollow portion 33. The position and shape of the recess 311 conform to the wing portion 14 of the retractor body 10. The retractor connection portion 31 is connected by a concave connecting portion 34 located on the lower side. The depth of the connecting portion 34 is approximately the same as the thickness of the fuselage portion 11 of the retractor body 10.

[0034] The auxiliary member connection section 32 consists of two upright walls 321 and 322 formed to extend in the XZ plane. The upright walls 321 and 322 are engageable with the slit 25 of the first auxiliary member 20. The upright walls 321 and 322 are used selectively in osteotomy. The thickness of the upright walls 321 and 322 matches the width of the slit 25. The distance between the upright walls 321 and 322 is, for example, about the same as the width of the body 11 of the retractor body 10. The upper ends of the upright walls 321 and 322 are open so as not to interfere with the osteotomy instrument during osteotomy.

[0035] Furthermore, in the upright walls 321 and 322, the surface 323 on the X-axis + side is inclined with respect to the Z-axis (hereinafter referred to as the "first inclined surface 323"). The first inclined surface 323 is displaced towards the X-axis + side as it moves toward the Z-axis + side (the side farther from the retractor body 10), and is formed so as not to overlap with the retractor connection part 31 when viewed from the Z-axis side. By attaching the second auxiliary member 30 to the retractor body 10 such that the first inclined surface 323 is on the bone contact part 12 side, that is, the side in close proximity to the bone, it is possible to prevent interference between the incision site and the second auxiliary member 30 while bringing the auxiliary member connection part 32 closer to the bone (see Figure 5B).

[0036] Similarly, in the upright walls 321 and 322, the X-axis-side surface 324 is also inclined with respect to the Z-axis direction (hereinafter referred to as the "second inclined surface 324"). The second inclined surface 324 is displaced toward the X-axis-side as it moves toward the Z-axis-side (the side further from the retractor body 10), and is formed to overlap with the retractor connection portion 31 when viewed from the Z-axis direction. In this embodiment, the inclination angles of the first inclined surface 323 and the second inclined surface 324 are the same. By providing the second inclined surface 324, interference between the bone cutting instrument S and the second auxiliary member 30 during bone cutting can be prevented (see Figure 5B).

[0037] The structure of the retractor body 10 (particularly the width of the guide groove 13), the first auxiliary member 20 (particularly the position of the insertion hole 23 and the slit 25 in the width direction), and the second auxiliary member 30 (particularly the position of the upright walls 321 and 322 in the width direction) is designed such that, when the bone cutting support jig 1 is installed (see Figures 5A and 5B), the guide pins K1 and K2 inserted into the first auxiliary member 20 (more specifically, the surfaces of the guide pins K1 and K2 that contact the bone cutting instrument) and the guide groove 13 of the retractor body 10 overlap in the vertical direction, and the cutting edge is inserted into the guide groove 13 when the bone cutting instrument is placed along the guide pins K1 and K2.

[0038] Figures 3A to 3D are schematic perspective views showing the installation method of the osteotomy support jig 1. Figures 4A to 4D are schematic side views showing the installation method of the osteotomy support jig 1. As an example, we will explain the case of osteotomy of the proximal bone fragment of the tibia B of the right leg in a high tibial osteotomy (HTO).

[0039] In high tibial osteotomy, the surgeon first exposes the proximal bone fragment of tibia B, the site of the osteotomy, by making an incision on the medial side of the right leg. Then, multiple guide pins K1 and K2 are inserted into tibia B according to the osteotomy plane predetermined in the preoperative plan (see Figures 3A and 4A). Ideally, the osteotomy plane should be perpendicular to the coronal plane of tibia B.

[0040] Guide pins K1 and K2 are inserted using a predetermined guide pin insertion jig. The spacing between guide pins K1 and K2 is determined, for example, by the guide pin insertion jig used. The number of guide pins K1 and K2 may be multiple, and there may be three or more. Even if there are multiple guide pins, they are aligned perpendicular to the coronal plane of the tibia, so they overlap in the X-ray image and appear as a single image.

[0041] Next, the surgeon inserts the retractor body 10 of the osteotomy support jig 1 into the incision site (see Figures 3B and 4B). Specifically, the retractor body 10 is positioned so that the bone contact surface 12a of the bone contact portion 121 of the retractor body 10 contacts the posterior cortical bone of the tibia B. Since a recess 12b that conforms to the shape of the tibia B is formed on one side in the width direction of the bone contact portion 121, the bone contact portion 121 fits the tibia B to a high degree of comfort.

[0042] Furthermore, it is confirmed that the guide pins K1 and K2 are positioned directly above the guide groove 13 of the retractor body 10. If the retractor body 10 is made of radiopaque metal, the guide groove 13 will also be visualized in the X-ray image due to differences in thickness within the retractor body 10. The surgeon can adjust the position of the retractor body 10 while confirming the positions of the guide groove 13 and the guide pins K1 and K2 using the X-ray image. Clear visualization of the guide groove 13 in the X-ray image means that the guide groove 13 is perpendicular to the coronal plane of the tibia.

[0043] In this embodiment, the positional relationship between the guide groove 13 and the guide pins K1 and K2 is automatically fixed by using the first auxiliary member 20 and the second auxiliary member 30. Therefore, it is sufficient to confirm that the position of the retractor body 10 is correct to a certain extent.

[0044] Next, the surgeon attaches the second auxiliary member 30 to the retractor body 10 (see Figures 3C and 4C). Specifically, the second auxiliary member 30 is positioned so that its inclined surface 323 is proximal to the tibia B, and then attached to the retractor body 10 from between the wings 141 and 142. Guide pins K1 and K2 are located between the upright walls 321 and 322 of the second auxiliary member 30. The second auxiliary member 30 is fixed to the retractor body 10 by engaging the retractor connection portion 31 of the second auxiliary member 30 with the wings 141 and sliding it.

[0045] Next, the surgeon inserts guide pins K1 and K2 through the insertion holes 231 and 232 of the first auxiliary member 20. The guide pins K1 and K2 are positioned along the guide surface 24 of the first auxiliary member 20. The guide surface 24 is parallel to the osteotomy surface defined by the guide pins K1 and K2. In this state, the first auxiliary member 20 is moved towards the second auxiliary member 30 along the guide pins K1 and K2. Then, the slit 25 of the first auxiliary member 20 and the upright wall 321 of the second auxiliary member 30 are engaged, connecting the second auxiliary member 30 and the first auxiliary member 20 (see Figures 3D and 4D).

[0046] The position of the second auxiliary member 30 is corrected according to the position of the first auxiliary member 20 (position of the slit 25), and consequently, the position of the retractor body 10 is corrected. That is, the positional relationship between the guide pins K1 and K2 and the guide groove 13 of the retractor body 10 is fixed via the first auxiliary member 20 and the second auxiliary member 30 (see Figures 5A and 5B). Figure 5A is a plan view of the bone cutting support jig 1 seen from above, and Figure 5B is a cross-sectional view taken along the line AA in Figure 5A.

[0047] As shown in Figure 5A, a portion of the guide groove 13 of the retractor body 10 in the width direction overlaps vertically with the guide pins K1 and K2 inserted through the first auxiliary member 20. On the other hand, the remaining portion of the guide groove 13 in the width direction is not covered by the guide pins K1 and K2 and is open to the upper side. The width of the portion of the guide groove 13 that is open to the upper side corresponds to the width of the bone cutting instrument S.

[0048] The surgeon guides the osteotomy instrument S along the guide pins K1 and K2 exposed from the first auxiliary member 20, inserts the tip of the osteotomy instrument S into the guide groove 13, and advances the osteotomy instrument S along the guide groove 13. Since the osteotomy instrument S is in contact with the retractor body 10, accidental cutting or damage to surrounding tissues by the osteotomy instrument S can be prevented, thus protecting the surrounding tissues. Furthermore, since the tip of the osteotomy instrument S is inserted into the guide groove 13 and can only move within the guide groove 13, it can be prevented from being bounced off the bone and moving to an unexpected position, and is guided in the predetermined direction in a stable position. Therefore, the surgeon can perform the osteotomy safely, accurately, and easily.

[0049] In particular, in high tibial osteotomy, the posterior cortical bone of the tibia B is the thickest and hardest bone. Therefore, the osteotomy instrument S often comes into contact with the bone contact surface of the retractor that is in contact with the posterior cortical bone and is repelled forward. If the osteotomy of the posterior cortical bone is insufficient, cracks may form in areas other than the osteotomy site, which may reduce clinical outcomes, but it is difficult to perform the osteotomy while visually confirming the process.

[0050] In contrast, when the osteotomy support jig 1 is applied, the bone contact surface 12a of the retractor body 10 is in contact with the posterior cortical bone, and the cutting edge of the osteotomy instrument S advancing along the guide groove 13 is reliably positioned below the posterior cortical bone. Therefore, if the osteotomy instrument S is advancing along the guide groove 13, the posterior cortical bone will inevitably be cut. Consequently, there is no need to repeat the steps of checking whether the bone has been cut and recutting, and the posterior cortical bone can be reliably cut in a single procedure.

[0051] As described above, the bone cutting support jig 1 according to this embodiment is equipped with the following features individually or in appropriate combinations.

[0052] In other words, the osteotomy support jig 1 is an osteotomy support jig used for osteotomy of the tibia B (long bone), and comprises a retractor body 10 that extends in the longitudinal direction and has a bone contact portion 12 at its end in the longitudinal direction, the bone contact portion 12 has a bone contact surface 12a on one side in the thickness direction that can contact the tibia B, and the retractor body 10 has a guide groove 13 formed along the longitudinal direction along its entire length on the same side as the bone contact surface 12a.

[0053] With the osteotomy support jig 1, during osteotomy, the retractor body 10 is inserted into the incision site, and the position and orientation of the retractor body 10 are adjusted so that the guide groove 13 aligns with the guide pins K1 and K2, thereby easily achieving protection of surrounding tissue and guidance of the osteotomy instrument S. Furthermore, since the retractor body 10, a single component, combines the functions of protecting surrounding tissue and guiding the osteotomy instrument S, it can be easily handled even by inexperienced surgeons.

[0054] Traditionally, even when guide pins were used to precisely set the osteotomy surface, the actual osteotomy technique was an inaccurate method that depended on the surgeon's skill in guiding the osteotomy instrument along the guide pins. With the osteotomy support jig 1, the osteotomy instrument S moves along the guide groove 13, allowing the surgeon to control the actual behavior of the osteotomy instrument S regardless of their skill, and significantly improving the accuracy of the osteotomy. Therefore, with the osteotomy support jig 1, osteotomy can be performed safely, accurately, and easily, regardless of the surgeon's skill.

[0055] In the osteotomy support jig 1, the bone contact surface 12a has a recess 12b on one side in the width direction that can fit the tibia B (long bone). This increases the contact area between the bone contact surface 12a and the tibia B, making the posture of the retractor body 10 relative to the tibia B more stable.

[0056] In the bone cutting support jig 1, the retractor body 10 has a structure that is symmetrical in the longitudinal direction. This allows for the use of different bone contact parts 121 and 122 depending on the form of use during bone cutting, thereby improving the convenience of the bone cutting support jig 1.

[0057] In the osteotomy support jig 1, the retractor body 10 is made of an X-ray transparent material. As a result, the guide groove 13 of the retractor body 10 is visualized in the X-ray image, allowing the surgeon to visually confirm what the osteotomy line will look like based on the X-ray image. Therefore, the surgeon can easily adjust the position of the retractor body 10 while confirming the positions of the guide groove 13 and guide pins K1 and K2 on the X-ray image, further improving the accuracy of the osteotomy. It also becomes easier to form an osteotomy surface perpendicular to the coronal plane of the tibia.

[0058] The bone cutting support jig 1 further comprises a first auxiliary member 20 that is detachable from one side of the retractor body 10 in the thickness direction. The first auxiliary member 20 has a guide pin holding portion 21 that can hold a plurality of guide pins K1, K2 that define the bone cutting surface, and a posture fixing portion 22 that fixes the relative posture between the retractor body 10 and the first auxiliary member 20. When the first auxiliary member 20 is attached to the retractor body 10, the guide groove 13 and the guide pins K1, K2 overlap in the thickness direction.

[0059] Furthermore, in the bone cutting support jig 1, the first auxiliary member 20 extends in the longitudinal direction, has a guide pin holding portion 21 at one end in the longitudinal direction, and has a posture fixing portion 22 at the other end in the longitudinal direction.

[0060] Furthermore, in the bone cutting support jig 1, the guide pin holding portion 21 has a plurality of insertion holes 231, 232 through which a plurality of guide pins K1, K2 can be individually inserted.

[0061] By configuring the osteotomy support jig 1 to include a first auxiliary member 20, the guide pins K1 and K2 and the retractor body 10 are integrated, and the position of the retractor body 10 relative to the guide pins K1 and K2, i.e., the position of the guide groove 13, is fixed. Therefore, the osteotomy surface formed by the guide pins K1 and K2 can be easily aligned with the guide groove 13 of the retractor body 10, improving the accuracy of the osteotomy. Furthermore, by correcting the distortion of the guide groove 13 of the retractor body 10 integrated with the guide pins K1 and K2 using X-ray images, accuracy can be further improved. In addition, complicated procedures for adjusting the position and position of the retractor body 10 or maintaining that position are unnecessary, so osteotomy can be performed easily and accurately.

[0062] The bone cutting support jig 1 further comprises a second auxiliary member 30 that connects the retractor body 10 and the first auxiliary member 20, and the second auxiliary member 30 has a retractor connection portion 31 that is connected to the retractor body 10 and an auxiliary member connection portion 32 that is connected to the first auxiliary member 20.

[0063] Furthermore, in the bone cutting support jig 1, the retractor body 10 has flat plate-shaped wing portions 14 on both sides in the width direction that can engage with the retractor connection portion, and the second auxiliary member 30 is attached to the retractor body 10 by sliding the retractor connection portion 31 along the wing portion 14.

[0064] Furthermore, in the bone cutting support jig 1, the second auxiliary member 30 has flat plate-shaped upright walls 321 and 322 (locking walls) extending in the thickness direction from the retractor connection portion 31, and the first auxiliary member 20 has a slit 25 in the posture fixing portion 22 that can engage with the upright walls 321 and 322.

[0065] By configuring the bone cutting support jig 1 to include a second auxiliary member 30, the retractor body 10 and the first auxiliary member 20 can be easily connected, and their relative positions can be fixed.

[0066] Incidentally, it is desirable for surgeons to have various solutions for a given disease. For example, in the case of osteoarthritis of the knee, there are surgical procedures such as osteotomy, artificial joint replacement, and arthroscopy, and ideally, the surgeon should choose the most suitable option from among them. However, currently, not all knee joint specialists perform osteotomy, and some surgeons focus solely on artificial joint replacement.

[0067] The osteotomy support jig 1 simplifies osteotomy procedures, which is expected to allow orthopedic surgeons who have previously avoided osteotomy (especially less experienced ones) to take on the challenge and perform the procedure, thereby contributing to an overall improvement in the skill level of orthopedic surgeons. As a result, the range of surgical options for conditions such as osteoarthritis of the knee will increase, enabling the selection of the most optimal surgical method and providing ideal medical care to patients.

[0068] Furthermore, regarding healthcare economics, approximately 100,000 costly total knee replacement surgeries are performed annually in Japan for osteoarthritis of the knee, which is 10 times the number of osteotomies performed (10,000). While total knee replacement surgery is performed for end-stage osteoarthritis of the knee, if the application of the osteotomy support jig 1 allows for low-cost osteotomies to be performed before the knee reaches the end-stage, the overall healthcare economic burden can be reduced.

[0069] Furthermore, when applying the osteotomy support jig 1, no additional procedures are required compared to conventional surgery, such as needing an extra guide pin or slightly expanding the surgical field. Therefore, there are no disadvantages to applying the osteotomy support jig 1; only the benefits of improved safety, accuracy, and ease of use provided by the osteotomy support jig 1 can be enjoyed.

[0070] [Second Embodiment] Figures 6A and 6B are external perspective views of the osteotomy support jig 2 according to the second embodiment. Figure 7 is an exploded perspective view of the osteotomy support jig 2. The osteotomy support jig 2 is a jig used for osteotomy of long bones, similar to the first embodiment.

[0071] As shown in Figure 6A, etc., the bone cutting support jig 2 includes a retractor body 40. In addition to the retractor body 40, the bone cutting support jig 2 also includes a first auxiliary member 50 and a second auxiliary member 60. Components that are the same as or corresponding to those in the bone cutting support jig 1 of the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0072] Compared to the bone cutting support jig 1 according to the first embodiment, the bone cutting support jig 2 differs in the configuration of the retractor body 40 and the second auxiliary member 60. The configuration of the first auxiliary member 50 is substantially the same as that of the first auxiliary member 20 according to the first embodiment.

[0073] The retractor body 40 differs from the retractor body 10 of the first embodiment in that it does not have the wing portion 141. The other components of the retractor body 40 are the same as those of the retractor body 10. Because the retractor body 40 has a simple structure without the wing portion 141, it can be manufactured more easily than the retractor body 10 of the first embodiment, and component costs can be reduced.

[0074] The second auxiliary member 60 is a member that connects the retractor body 40 and the first auxiliary member 50. The second auxiliary member 60 has a retractor connection portion 61 and an auxiliary member connection portion 62. The retractor connection portion 61 is the part that connects to the retractor body 40. The auxiliary member connection portion 62 is the part that connects to the first auxiliary member 50. The retractor connection portion 61 and the auxiliary member connection portion 62 may be integrally molded as a single member, or they may be molded separately and then joined together to form a single unit.

[0075] The auxiliary member connection section 62 is composed of two plate members 63 and 64. The plate members 63 and 64 are arranged opposite each other in the Y-axis direction so that their thickness direction coincides with the Y-axis direction, and can be positioned along both sides of the width direction (Y-axis direction) of the retractor body 40. The distance between the plate members 63 and 64 is approximately the same as the width of the retractor body 40.

[0076] Each plate member 63 and 64 has a main body wall 621 that runs along the retractor body 40, and a locking wall 622 that protrudes upward from one end of the main body wall 621 in the longitudinal direction (the tip in the X-axis direction).

[0077] The locking wall 622 is engageable with the slit 25 of the first auxiliary member 20. The locking walls 622 of the plate members 63 and 64 are used selectively in osteotomy. The thickness of the locking wall 622 is adapted to the width of the slit 25. The upper end of the locking wall 622 is open to avoid interference with the osteotomy instrument during osteotomy. The shape of the locking wall 622 is the same as that of the upright walls 321 and 322 in the first embodiment.

[0078] In the plate members 63 and 64, the upper surfaces of the main body wall 621 are connected via the retractor connection portion 61. On the other hand, the lower surfaces of the main body wall 621 are not connected to each other and are open along their entire length. This allows the second auxiliary member 60 to be easily attached to the retractor body 40 by fitting it from above.

[0079] The retractor connection portion 61 is positioned to straddle the upper surfaces of the two plate members 63 and 64, specifically the upper surface of the main body wall 621, and connects the plate members 63 and 64. The retractor connection portion 61 has an engaging piece 611 formed to protrude downward from the center in the Y-axis direction. In other words, the retractor connection portion 61 has a T-shape when viewed from the X-axis direction.

[0080] The retractor connection portion 61 comes into contact with the upper surface of the body portion 11 of the retractor body 40 when the second auxiliary member 60 is installed on the retractor body 40. At this time, the engaging piece 611 engages with the guide groove 13 of the retractor body 40. As a result, the second auxiliary member 60 is held in a stable position.

[0081] The retractor connection portion 61 is located at the other end of the main body wall 621 in the longitudinal direction (the rear end in the X-axis direction). In other words, the retractor connection portion 61 is positioned apart from the locking wall 622 so as not to interfere with the bone cutting instrument during bone cutting.

[0082] Thus, the bone cutting support jig 2 according to the second embodiment is equipped with the following features, either individually or in appropriate combinations, in addition to the features of the bone cutting support jig 2 according to the first embodiment.

[0083] In other words, the bone cutting support jig 2 includes a second auxiliary member 60 that connects the retractor body 40 and the first auxiliary member 50, and the second auxiliary member 60 has a retractor connection part 61 that is connected to the retractor body 40 and an auxiliary member connection part 62 that is connected to the first auxiliary member 50. By configuring the bone cutting support jig 1 to include the second auxiliary member 30, the retractor body 10 and the first auxiliary member 20 can be easily connected and their positional relationship can be fixed.

[0084] In the bone cutting support jig 2, the auxiliary member connection section 62 is composed of two plate members 63 and 64 that can be positioned along both sides in the width direction of the retractor body 40, and the retractor connection section 61 is positioned to straddle the upper surfaces of the two plate members 63 and 64, and the two plate members 63 and 64 are connected with their lower sides open. The second auxiliary member 60 can be realized with a simple configuration, and the second auxiliary member 60 can be easily attached to the retractor body 40 from above.

[0085] In the bone cutting support jig 2, the retractor connection portion 61 has an engaging piece 611 that can engage with the guide groove 13. The second auxiliary member 60 can be installed in a stable position relative to the retractor body 40, and its position in the longitudinal direction can also be easily adjusted.

[0086] In the bone cutting support jig 2, the two plate members 63 and 64 each have a main body wall 621 that runs along the retractor body 40 and a locking wall 622 that protrudes upward from one end of the main body wall 621 in the longitudinal direction. The first auxiliary member 50 has a slit 25 in the posture fixing part 22 that can engage with the locking wall 622. The first auxiliary member 50 can be easily attached to the second auxiliary member 60, and consequently, the retractor body 10 and the first auxiliary member 20 can be easily connected, and their positional relationship can be fixed.

[0087] In the bone cutting support jig 2, the retractor connection part 61 is positioned at the other end in the longitudinal direction of the main body wall 621 and is spaced apart from the locking wall 622. This prevents the movement of the bone cutting instrument from being restricted by the retractor connection part 61 during bone cutting, allowing the bone cutting instrument to move freely and thus enabling high-quality bone cutting.

[0088] Although the present invention has been specifically described above based on embodiments, the present invention is not limited to the above embodiments and can be modified without departing from its spirit.

[0089] For example, the bone cutting support jig 1 described in the embodiment includes a first auxiliary member 20 and a second auxiliary member 30 together with the retractor body 10, but the retractor body 10 can also be used on its own.

[0090] Furthermore, the osteotomy support jig according to the present invention can be applied not only to high tibial osteotomy as described in the embodiment, but also to corrective osteotomy of long bones such as the femur.

[0091] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0092] 1. Bone cutting support jig 10 Retractor Body 11 Torso 12 Bone contact part 13 Guide grooves 14 Wings 20 First auxiliary member 21 Guide pin holding part 22 Posture fixing part 23 Through hole 24 Guide surface 25 slits 30 Second auxiliary member 31 Retractor connection 32 Auxiliary member connection part 321, 322 Standing wall (engaging wall)

Claims

1. A bone cutting support jig used for osteotomy of long bones, The retractor body extends in the longitudinal direction and has bone contact portions at its ends in the longitudinal direction, The bone contact portion has a bone contact surface on one side in the thickness direction that can contact the long bone, The retractor body has a guide groove formed along the longitudinal direction over its entire length on the same side as the bone contact surface, Bone cutting support jig.

2. The bone contact surface has a recess on one side in the width direction that can fit the long bone. The bone cutting support jig according to claim 1.

3. The retractor body has a structure that is symmetrical in the longitudinal direction. The bone cutting support jig according to claim 2.

4. The retractor body is made of an X-ray transparent material. The bone cutting support jig according to claim 1.

5. The retractor body is provided with a first auxiliary member that is detachable from one side in the thickness direction, The first auxiliary member is, A guide pin holder capable of holding multiple guide pins that define the bone cutting surface, It has a posture fixing part that fixes the relative posture between the retractor body and the first auxiliary member, When the first auxiliary member is attached to the retractor body, the guide groove and the guide pin overlap in the thickness direction. The bone cutting support jig according to claim 1.

6. The first auxiliary member extends in the longitudinal direction, has the guide pin holding portion at one end in the longitudinal direction, and has the posture fixing portion at the other end in the longitudinal direction. The bone cutting support jig according to claim 5.

7. The guide pin holding portion has a plurality of insertion holes through which a plurality of guide pins can be individually inserted. The bone cutting support jig according to claim 6.

8. The retractor body and the first auxiliary member are connected by a second auxiliary member, The second auxiliary member has a retractor connection portion connected to the retractor body and an auxiliary member connection portion connected to the first auxiliary member. The bone cutting support jig according to claim 7.

9. The retractor body has flat, plate-shaped wing portions on both sides in the width direction that can engage with the retractor connection portion. The second auxiliary member is attached to the retractor body by sliding the retractor connection portion along the wing portion. The bone cutting support jig according to claim 8.

10. The second auxiliary member has a flat plate-shaped locking wall extending in the thickness direction from the retractor connection portion, The first auxiliary member has a slit in the posture fixing portion that can engage with the locking wall. The bone cutting support jig according to claim 8.

11. The auxiliary member connection portion is composed of two plate members that can be positioned along both sides in the width direction of the retractor body. The retractor connection portion is positioned to straddle the upper surfaces of the two plate members, The two aforementioned plate members are connected with their lower surfaces open. The bone cutting support jig according to claim 8.

12. The retractor connection portion has an engaging piece that can engage with the guide groove. The bone cutting support jig according to claim 11.

13. The two plate members each have a main body wall that runs along the retractor body and a locking wall that protrudes upward from one end of the main body wall in the longitudinal direction. The first auxiliary member has a slit in the posture fixing portion that can engage with the locking wall. The bone cutting support jig according to claim 11.

14. The retractor connection portion is located at the other end of the main body wall in the longitudinal direction and is spaced apart from the locking wall. The bone cutting support jig according to claim 13.

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