Spacer insertion instrument

Abstract

To provide a spacer insertion tool that can accurately and easily arrange a spacer in a bone resection part so that a side surface of the spacer coincides with an outer periphery of a bone resection surface.SOLUTION: A spacer insertion tool 100 comprises a first member 1 having a first holding part 4 on a tip side, and a second member 2 having a second holding part 7 on a tip side. The first and second holding parts 4 and 7 hold a side surface 23 of a spacer 20. The first holding part 4 has a larger width than a width of the side surface 23, and is inserted outside a bone. The second holding part 7 has a smaller width than the width of the side surface 23, and is inserted inside a bone resection part. A first supporting surface 4a of the first holding part 4 supporting the side surface 23 has a contact region protruding in a width direction from the side surface 23, and capable of being in contact with an outer surface of the bone.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a spacer insertion instrument.

Background Art

[0002] Conventionally, as a treatment for correcting the inward-biased load due to O-leg deformation caused by osteoarthritis of the knee or the like, opening wedge high tibial osteotomy (OWHTO) has been performed. As shown in FIG. 11(c), in OWHTO, a spacer 30 such as artificial bone is inserted into a wedge-shaped osteotomy portion C between osteotomy surfaces B1 and B2. A general wedge-shaped spacer 30 is disposed at the front and rear portions of the osteotomy portion C. In such bone surgeries including HTO, an instrument for gripping bone is used (see, for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] As shown in FIGS. 12(a) to (e) and FIG. 13, a novel spacer 20 for OWHTO having an outer peripheral shape substantially matching the anatomical shape of the outer periphery E of the inner rear portion D of the osteotomy surfaces B1 and B2 has been proposed. The spacer 20 needs to be disposed in the osteotomy portion C such that the side surface 23c having the outer peripheral shape coincides with the outer periphery E of the inner rear portion D. However, it is difficult to accurately dispose the spacer 20 in such a position through a small incision formed in the skin.

[0005] The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a spacer insertion instrument capable of accurately and easily arranging a spacer in a bone cutting portion so that the side surface of the spacer coincides with the outer periphery of the bone cutting surface.

Means for Solving the Problems

[0006] One aspect of the present invention is a spacer insertion instrument for inserting a spacer into a bone cutting portion formed in a bone, wherein the spacer has a first surface and a second surface that face each other and are respectively arranged along a first bone cutting surface and a second bone cutting surface of the bone cutting portion, and a side surface that connects the first surface and the second surface, a first member having a first gripping portion on the tip side and a first handle portion on the base end side, and a second member having a second gripping portion on the tip side and a second handle portion on the base end side, the first gripping portion and the second gripping portion face each other, grip the spacer on the side surface, the first gripping portion has a width larger than the width between the first surface and the second surface of the side surface, is inserted outside the bone, the second gripping portion has a width smaller than the width of the side surface, is inserted into the bone cutting portion, and a first support surface on the second gripping portion side that supports the side surface of the first gripping portion has a contact region that protrudes from the side surface in the width direction of the side surface and can contact the outer surface of the bone.

Effects of the Invention

[0007] According to the present invention, there is an effect that the spacer can be accurately and easily arranged in the bone cutting portion so that the side surface of the spacer coincides with the outer periphery of the bone cutting surface.

Brief Description of the Drawings

[0008]

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MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, a spacer insertion instrument according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 11(a) and (b), the spacer insertion instrument 100 according to the present embodiment is used to insert a spacer 20 such as artificial bone into a bone cut portion C between bone cut surfaces B1 and B2 formed at a bone end portion of a tibia A in an open-wedge high tibial osteotomy (OWHTO).

[0010] The instrument 100 is particularly suitable for inserting the spacer 20 shown in FIGS. 12(a) to (e) into the bone cut portion C. The spacer 20 has a first surface 21 and a second surface 22 that face each other and are disposed along the first bone resection surface B1 and the second bone resection surface B2, respectively, and a side surface 23 that connects the outer periphery of the first surface 21 to the second surface 22. The bone resection surfaces B1 and B2 have the same shape, and therefore the first surface 21 and the second surface 22 also have the same shape. The second surface 22 is inclined at an angle θ with respect to the first surface 21, and the angle θ is the correction angle of the tibia A.

[0011] The side surface 23 has a flat first side surface 23a, a flat second side surface 23b that intersects with the first side surface 23a, and a curved third side surface 23c that connects the first side surface 23a and the second side surface 23b. The first side surface 23a and the second side surface 23b are located on the anterior and lateral sides, respectively, of the osteotomy portion C, and the third side surface 23c is located on the medial and posterior sides of the osteotomy portion C (see FIGS. 8(c) and 8(d)).

[0012] The third side surface 23c is a curved surface that is convex outward and has a curved shape that substantially matches the anatomical shape of the outer periphery E of the medial posterior portion D of the patient's resection surfaces B1 and B2. As shown in FIG. 13, the medial posterior portion D is located medially relative to the first axis Q1 and posterior relative to the second axis Q2. The first axis Q1 extends in a direction parallel to the anterior-posterior direction of the tibia A and is located a first distance d1 (e.g., 28.5 mm or more and 30 mm or less) outward from the medial projection point P1. The second axis Q2 extends in a direction parallel to the medial-lateral direction of the tibia A and is located a second distance d2 (e.g., 22.7 mm or more and 35 mm or less) anterior to the posterior projection point P2. The medial projection point P1 is the medialmost position of the resection surfaces B1 and B2. The posterior projection point P2 is the posteriormost position of the resection surfaces B1 and B2, medial to the first axis Q1.

[0013] The anatomical shapes of the outer periphery E of the medial posterior portion D of almost all patients are substantially the same. Therefore, by placing the spacer 20 in the osteotomy portion C so that the third side surface 23c is aligned with the outer periphery E of the medial posterior portion D, the tibia A can be accurately corrected by the desired correction angle θ in almost all patients. That is, in order to obtain the accurate correction angle θ, it is necessary to align the third side surface 23c with respect to the outer periphery E of the inner rear portion D. On the other hand, soft tissue F including ligaments exists around the tibia A. The spacer insertion instrument 100 enables accurate placement of the spacer 20 within the osteotomy portion C while protecting the soft tissue F.

[0014] As shown in FIGS. 1 to 5, the spacer insertion instrument 100 includes a first member 1, a second member 2, and a connection mechanism 3 that connects the first member 1 and the second member 2 so as to be relatively movable. Each of the members 1 and 2 is an elongated strip-shaped member having a tip and a base end, and extends straight in a plan view when viewed in the thickness direction (see, for example, FIGS. 1(a) and 2(a)). The first member 1 has a first gripping portion 4 on the tip side and a first handle portion 5 on the base end side. The second member 2 has a second gripping portion 7 on the tip side and a second handle portion 8 on the base end side.

[0015] The two members 1 and 2 are arranged in the thickness direction, and the flat second handle portion 8 is disposed on the flat first handle portion 5. Hereinafter, the arrangement direction of the two members 1 and 2 is defined as the height direction Z of the instrument 100, the width direction (short side direction) of the members 1 and 2 is defined as the width direction X of the instrument 100, and the longitudinal direction of the members 1 and 2 orthogonal to the height direction Z and the width direction X is defined as the length direction Y of the instrument 100.

[0016] The first member 1 has a curved portion 6 that curves around the axis in the width direction X toward the side opposite to the second member 2 between the first gripping portion 4 and the first handle portion 5, and the first gripping portion 4 is disposed at a distance from the second gripping portion 7 in the height direction Z. The pair of gripping portions 4 and 7 face each other in the height direction Z and grip the spacer 20 on the side surface 23.

[0017] The surface 4a of the first gripping portion 4 on the side of the second member 2 is a first support surface that contacts and supports the third side surface 23c. The surface 7a of the second gripping portion 7 on the side of the first member 1 is a second support surface that contacts and supports the first side surface 23a. In order to improve the fixity of the spacer 20 to the gripping portions 4 and 7, a groove 23d into which the second gripping portion 7 fits may be formed in the first side surface 23a (see, for example, FIG. 12(b)).

[0018] The first gripping portion 4 has a flat tip portion 41 including the tip of the first member 1, and a base end portion 42 connecting the base end of the tip portion 41 and the tip of the curved portion 6. The tip portion 41 is parallel or substantially parallel to the handle portions 5 and 8 in a side view when viewed in the width direction X. The base end portion 42 curves around the axis in the width direction X so as to be convex toward the side opposite to the second gripping portion 7. Accordingly, the first member 1 has a substantially crank shape in a side view (see FIGS. 1(b) and 2(b)). The second member 2 is flat over the entire length from the tip to the base end in a side view. The second gripping portion 7 is thinner than the second handle portion 8, the first gripping portion 4, and the first handle portion 5 in the width direction X.

[0019] As shown in FIGS. 3(a) and 3(b), the width W1 of the first gripping portion 4 is larger than the width α of the side surface 23 between the surfaces 21 and 22 over the entire length from the tip to the base end of the first gripping portion 4. The width W2 of the second gripping portion 7 is smaller than the width α over the entire length from the tip to the base end of the second gripping portion 7. The widths W1 and W2 are dimensions in the width direction X. The width of the bone cutting portion C between the bone cutting surfaces B1 and B2 is approximately the same as the width α of the side surface 23. Accordingly, the second gripping portion 7 can be inserted into the bone cutting portion C. On the other hand, the first gripping portion 4 is inserted outside the tibia A along the outer surface of the tibia A (see FIGS. 8(a) to 8(d)). That is, the first gripping portion 4 functions as a retractor that is disposed between the spacer 20 and the soft tissue F around the tibia A and protects the soft tissue F.

[0020] The first support surface 4a has contact regions 4b that protrude in the width direction X from the side surface 23c on both sides in the width direction X of the third side surface 23c supported by the first support surface 4a. In FIGS. 3(a) and 3(b), the contact regions 4b are indicated by hatching. The contact regions 4b on both sides can contact the outer surface of the tibia A at the proximal side and the distal side of the osteotomy portion C. By bringing the contact regions 4b into contact with the outer surface of the tibia A, the third side surface 23c is made to coincide with the outer periphery E of the osteotomy surfaces B1 and B2.

[0021] In plan view, the first gripping portion 4 may be substantially trapezoidal with a gradually decreasing width W1 toward the tip as shown in FIG. 3(a), or may be substantially rectangular with a constant width W1 as shown in FIG. 3(b). In order to be able to easily insert the first gripping portion 4 along the outer surface of the tibia A while avoiding interference with the soft tissue F, the first gripping portion 4 with a narrow width as shown in FIG. 3(a) is preferred.

[0022] The length L1 of the first gripping portion 4 is greater than the length β of the spacer 20, and the length L2 of the second gripping portion 7 is smaller than the length β. The lengths L1 and L2 are the dimensions of the gripping portions 4 and 7 in the length direction Y (see FIG. 1(b)), and the length β is the maximum dimension of the spacer 20 in the inner-outer direction (see FIG. 12(a)). Therefore, the tip of the first gripping portion 4 is disposed at a position protruding in the length direction Y from the second side surface 23b of the tip of the spacer 20.

[0023] The first support surface 4a of the tip portion 41 contacts the rear portion of the third side surface 23c at at least one point, and the first support surface 4a of the base end portion 42 contacts the inner portion of the third side surface 23c at at least one point. In order to increase the contact area with the third side surface 23c of the base end portion 42, it is preferable that at least a part of the first support surface 4a of the base end portion 42 has a curved shape that substantially conforms to the shape of the outer periphery E of the inner rear portion D. Specifically, the third side surface 23c has two radii of curvature R1 and R2 corresponding to the shape of the outer periphery E of the inner rear portion D (see FIG. 12). R1 is the radius of curvature of the portion corresponding to the vicinity of the inner protruding point P1, and R2 is the radius of curvature of the portion on the rear side of the portion of R1. Based on such a curved shape of the third side surface 23c, the first support surface 4a of the base end portion 42 may have two curved portions 42a and 42b with different radii of curvature (see FIGS. 1(b) and 2(b)). For example, the radius of curvature of the first support surface 4a of the first curved portion 42a on the base end side is preferably 8 mm or more and 10 mm or less, and the radius of curvature of the first support surface 4a of the second curved portion 42b on the tip side is preferably 20 mm or more and 22 mm or less.

[0024] In order to insert the spacer 20 into the bone cutting portion C, the instrument 100 may be struck with a hammer. The larger the contact area with the side surface 23c of the base end portion 42, the more the force applied from the hammer to the spacer 20 via the instrument 100 can be spatially dispersed, preventing the concentration of force. A portion to be struck 5c that is struck with a hammer may be provided at the base end of the first handle portion 5. The portion to be struck 5c is formed, for example, from the base end portion of the first handle portion 5 that is curved by about 90°.

[0025] In one design example, the width W1 of the tip portion 41 is preferably 5 mm or more and 18 mm or less, and the length L3 of the tip portion 41 is preferably 20 mm or more and 30 mm or less. The width W2 of the second grip portion 7 is preferably 1 mm or more and 2 mm or less, and the length L2 of the second grip portion 7 is preferably 20 mm or more and 30 mm or less.

[0026] When the width W1 is less than 5 mm, the first grip portion 4 may enter the bone cutting portion C, making it difficult to bring the contact region 4b into contact with the outer surface of the tibia A. When the width W1 is greater than 18 mm, the fit of the contact region 4b to the outer surface of the tibia A deteriorates, and the gap between the contact region 4b and the outer surface of the tibia A increases. When the length L3 is less than 20 mm, the gap between the tip of the spacer 20 and the tip of the first gripping portion 4 becomes small, and there is a possibility that the first gripping portion 4 may not function effectively as a retractor. When the length L3 is greater than 30 mm, it may become difficult to insert the spacer 20 to an appropriate position of the osteotomy portion C because the tip of the first gripping portion 4 abuts against the outer condyle G (see FIG. 13) of the posterior surface of the tibia A.

[0027] The connecting mechanism 3 connects the first member 1 and the second member 2 such that the second member 2 is movable longitudinally between a first position and a second position with respect to the first member 1. The first position is a position where the tip of the second gripping portion 7 (i.e., the tip of the second member 2) is disposed between the proximal end and the distal end of the distal portion 41 (see FIGS. 1(a) and (b)). When the second member 2 is disposed at the first position, the pair of gripping portions 4 and 7 facing each other in the height direction Z can grip the spacer 20. The second position is a position where the tip of the second gripping portion 7 is disposed at or near the proximal end of the first gripping portion 4 (see FIGS. 2(a) and (b)). When the second member 2 is disposed at the second position, the pair of gripping portions 4 and 7 releases the spacer 20.

[0028] FIG. 6 shows an example of the connecting mechanism 3. The connecting mechanism 3 includes a connecting member 9 and an elastic member 10. The connecting member 9 has a columnar shaft portion 9a and two heads 9b and 9c provided at both ends of the shaft portion 9a and having a larger diameter than the shaft portion 9a. The connecting member 9 is, for example, a screw pair including a male screw 91 having the first head 9b and a female screw 92 having the second head 9c. The elastic member 10 is, for example, a compression coil spring disposed around the shaft portion 9a.

[0029] The first handle portion 5 has a slot 11 penetrating in the thickness direction and extending in the longitudinal direction (see FIGS. 4(a) and (b)), and the second handle portion 8 has a hole 12 penetrating in the thickness direction and communicating with a part of the slot 11 in the height direction Z (see FIGS. 5(a) and (b)). As shown in FIGS. 7(a) to 7(d), the shaft portion 9a penetrates through the slots 11 and the holes 12 so as to be movable in the height direction Z, and the two head portions 9b and 9c are arranged on both sides of the handle portions 5 and 8 in the height direction Z. The elastic member 10 is disposed between the first head portion 9b on the side of the second handle portion 8 and the second handle portion 8, and biases the first head portion 9b and the second handle portion 8 in a direction away from each other.

[0030] As shown in FIG. 7(a), in the normal state, due to the biasing force of the elastic member 10, a force in a direction of mutual adhesion acts on the two handle portions 5 and 8, whereby the second member 2 is fixed to the first member 1. Specifically, the elastic member 10 presses the second handle portion 8 toward the first handle portion 5, and the second head portion 9c on the side of the first handle portion 5 presses the first handle portion 5 toward the second handle portion 8.

[0031] As shown in FIGS. 7(b) and 7(c), when the user presses down the first head portion 9b on the side of the second handle portion 8 against the biasing force of the elastic member 10, the fixing of the second handle portion 8 is released. In the released state, by the movement of the shaft portion 9a in the slot 11, the second member 2 becomes movable between the first position and the second position with respect to the first member 1. After the movement of the second member 2, as shown in FIG. 7(d), by releasing the first head portion 9b, the second member 2 is fixed again to the first member 1 by the biasing force of the elastic member 10.

[0032] Next, a method of using the spacer insertion instrument 100 will be described. In OWHTO, the bone end portion of the tibia A is osteotomized with a bone saw from the inner surface toward the outer side, and the space between the osteotomy surfaces B1 and B2 is widened with a retractor. The bone saw and the retractor are inserted into the knee through an incision formed in the skin on the inner side of the knee. Subsequently, as shown in Fig. 8(a), a pair of gripping portions 4 and 7 that grip the spacer 20 are inserted into the knee from the incision, and the spacer 20 is inserted into the osteotomy portion C from the inside toward the outside while aligning the first surface 21 and the second surface 22 with the osteotomy surfaces B1 and B2, respectively. At this time, the second gripping portion 7 is inserted into the osteotomy portion C between the osteotomy surfaces B1 and B2, and the first gripping portion 4 is inserted outside the tibia A. The first gripping portion 4 advances along the outer surface of the tibia A while keeping a soft tissue F such as the medial collateral ligament (MCL) away from the tibia A, and the tip portion 41 is disposed on the posterior side of the tibia A.

[0033] Next, as shown in Fig. 8(b), the first support surfaces 4a of the tip portion 41 and the base end portion 42 disposed on the posterior side and the inner side of the tibia A, respectively, are abutted against the outer surface of the inner posterior portion D of the tibia A. Thereby, the contact regions 4b of the tip portion 41 and the base end portion 42 come into contact with the outer surface of the tibia A at the distal side and the proximal side of the osteotomy portion C, and the spacer 20 is positioned at a position where the third side surface 23c coincides with the outer periphery E of the inner posterior portion D of the osteotomy surfaces B1 and B2.

[0034] After positioning the spacer 20, the widening of the osteotomy portion C by the retractor is released. Next, as shown in Fig. 8(c), by depressing the first head portion 9b, the fixing of the second member 2 is released, and the second member 2 is slid to the second position. Thereby, the spacer 20 is released from the gripping portions 4 and 7. Next, as shown in Fig. 8(d), while rotating the first member 1 toward the front side, it is pulled out from between the tibia A and the soft tissue F.

[0035] Thus, according to the present embodiment, the first support surface 4a that supports the third side surface 23c has contact regions 4b on both sides in the width direction of the third side surface 23c. Therefore, by simply bringing the contact regions 4b into contact with the outer surface of the tibia A, the third side surface 23c of the spacer 20 in the osteotomy portion C can be made to coincide with the outer periphery E of the inner posterior portion D of the osteotomy surfaces B1 and B2. Thereby, the spacer 20 can be accurately and easily disposed in the osteotomy portion C. In particular, the rear portion of the third side surface 23c disposed on the rear side of the tibia A is difficult to visually observe through the skin incision. According to the present embodiment, by simply bringing the contact area 4b of the distal end portion 41 on the rear side of the tibia A into contact with the rear surface of the tibia A, the rear portion of the third side surface 23c can be easily aligned with the outer periphery E.

[0036] Also, according to the present embodiment, the first gripping portion 4 inserted between the tibia A and the soft tissue F functions as a retractor for protecting the soft tissue F. Therefore, the spacer 20 can be inserted into the osteotomy portion C while protecting the soft tissue F around the tibia A using only the instrument 100. In particular, when the spacer 20 is inserted into the osteotomy portion C, by disposing the tip of the first gripping portion 4 in front of the spacer 20, the soft tissue F can be effectively protected.

[0037] Also, according to the present embodiment, the first handle portion 5 is parallel or substantially parallel to the distal end portion 41. During the operation, the surgeon cannot visually observe the distal end portion 41 inside the knee. By the first handle portion 5 being parallel or substantially parallel to the distal end portion 41, the surgeon can recognize the direction of the distal end portion 41 inside the knee based on the direction of the first handle portion 5, and can appropriately adjust the direction of the first gripping portion 4 inside the knee so that the first gripping portion 4 is disposed in the medial-lateral direction of the tibia A.

[0038] In the above embodiment, the support surface 4a of the proximal end portion 42 is in contact with the third side surface 23c. However, the support surface 4a of the proximal end portion 42 does not necessarily have to be in contact with the third side surface 23c. That is, the first gripping portion 4 may be in contact with the third side surface 23c at least at the support surface 4a of the distal end portion 41, and the proximal end portion 42 may have any shape. The inner portion of the third side surface 23c disposed on the inner side of the tibia A can be visually observed through the skin incision. Therefore, the alignment of the rear portion of the third side surface 23c with the outer periphery E may be performed using the contact area 4b of the distal end portion 41, and the alignment of the inner portion of the third side surface 23c with the outer periphery E may be performed visually.

[0039] In the above-described embodiment, it is preferable that the spacer insertion instrument 100 further includes a guide mechanism 13 that restricts the moving direction of the second handle portion 8 with respect to the first handle portion 5 in the length direction Y. By providing the guide mechanism 13, the second member 2 can be slid straight in the length direction Y with respect to the first member 1 without wobbling in the width direction X.

[0040] An example of the guide mechanism 13 includes a convex portion 13a and a guide groove 13b that receives the convex portion 13a in the height direction Z. As shown in FIGS. 5(a) and 5(b), the convex portion 13a is provided on the lower surface 8b of the second handle portion 8 on the side of the first handle portion 5 and protrudes in the height direction Z from the lower surface 8b. As shown in FIGS. 4(a) and 4(b), the guide groove 13b is provided on the upper surface 5a of the first handle portion 5 on the side of the second handle portion 8 and extends linearly in the length direction Y. The width of the guide groove 13b is substantially equal to the width of the convex portion 13a, and the movement of the convex portion 13a within the guide groove 13b is restricted only in the length direction Y. The arrangements of the convex portion 13a and the guide groove 13b may be reversed. That is, the convex portion 13a may be provided on the upper surface 5a and the guide groove 13b may be provided on the lower surface 8b.

[0041] In the above-described embodiment, in order to improve the gripping force of the spacer 20 by the gripping portions 4 and 7, the second support surface 7a may be inclined in a direction gradually approaching the first support surface 4a toward the tip. As shown in FIG. 5(a), the inclination of the second support surface 7a with respect to the first support surface 4a may be formed by a wedge-shaped convex portion 13a that becomes thinner in the height direction Z toward the tip. According to this configuration, the gripping force can be increased without adding a member to the gripping portions 4 and 7 inserted into the knee.

[0042] In the above-described embodiment, it is preferable that the first gripping portion 4 has an anti-slip member 17 for preventing the spacer 20 from slipping on the first support surface 4a. The anti-slip member 17 is provided in a region that contacts the spacer 20 on the first support surface 4a (see, for example, FIGS. 1(a) and 2(a)). The anti-slip member 17 may be composed of a fine concavo-convex structure formed on the first support surface 4a, or may be composed of a member having a high friction coefficient such as silicone rubber fixed to the first support surface 4a. The spacer 20 gripped by the gripping portions 4 and 7 is unstable with respect to the force in the width direction X. In order to enhance the stability in the width direction X, the concavo-convex structure may be composed of a plurality of convex portions extending parallel to each other in the length direction Y.

[0043] In the above-described embodiment, the second member 2 is disengaged from the first member 1 by a one-touch operation of pushing the connecting member 9. Instead of this, the second member 2 may be detachably fixed to the first member 1 by a fixing member such as a screw. FIGS. 9 and 10 show a spacer insertion instrument 101 according to another embodiment. The first member 1 has a screw hole 14 penetrating in the thickness direction, and the second member 2 has a slot 15 penetrating in the thickness direction and extending in the length direction Y. The connecting mechanism 3 of the instrument 101 has a fixing screw 16 inserted into the screw hole 14 through the slot 15. By tightening the fixing screw 16, the second member 2 is fixed to the first member 1, and by loosening the fixing screw 16, the second member 2 is disengaged and becomes movable in the length direction Y.

[0044] The guide mechanism of the spacer insertion instrument 101 is fixed to the side surfaces on both sides of the second handle portion 8 and has a pair of guide pieces 13c and 13d protruding in the height direction Z from the lower surface 8b. The second member 2 is guided in the length direction Y by the pair of guide pieces 13c and 13d that move along the side surfaces on both sides of the first handle portion 5. The pair of guide pieces 13c and 13d may be fixed to the side surfaces on both sides of the first handle portion 5 and configured to move along the side surfaces on both sides of the second handle portion 8.

[0045] In the above embodiment, the connecting mechanism 3 is configured to connect the two members 1 and 2 so as to be relatively movable in the longitudinal direction Y. However, alternatively, the two members 1 and 2 may be connected so as to be separable from each other. For example, the connecting mechanism may fix the second member 2 to the first member 1 removably by a fixing member such as a screw. After the spacer 20 is disposed in the osteotomy portion C, the spacer 20 is released by removing the second member 2 from the first member 1. Thus, when the two members 1 and 2 are not relatively moved in the longitudinal direction Y, the handle portions 5 and 8 do not necessarily have to be linear and flat, and may be curved.

[0046] In the above embodiment, the first member 1 and the second member 2 are separate members. However, alternatively, the first member and the second member may be formed of a single member. For example, the first member and the second member may be continuous with each other at their proximal ends, and the spacer insertion instrument may have a shape like forceps.

[0047] In the above embodiment, in order to confirm the directions of the gripping portions 4 and 7 inside the knee from outside the body, the gripping portions 4 and 7 may be visible under fluoroscopy and may have markers indicating the directions of the gripping portions 4 and 7. For example, the marker may be a protrusion provided at the tip of the gripping portion 4 and 7, or may be a thickened portion provided along the center line of the gripping portion 4 and 7.

[0048] Also, in the present embodiment, a spacer insertion instrument 100 that sandwiches the spacer 20 between the first support surface 4a on the second member 2 side of the first gripping portion 4 and the second support surface 7a on the first member 1 side of the second gripping portion 7 is illustrated. Then, the width W1 of the first gripping portion 4 is made larger than the width α of the side surface 23 at each position over the entire length from the tip to the base end of the first gripping portion 4, and a contact region 4b that can contact the outer surface of the tibia A is provided on the first support surface 4a on the proximal side and the distal side of the osteotomy portion C. That is, the first support surface 4a of the first gripping portion 4 has both the function of supporting the spacer 20 and the function of aligning the third side surface 23c of the spacer 20 with the outer periphery E of the osteotomy surfaces B1 and B2 of the tibia A, and the first member 1 is configured to be compact.

[0049] Alternatively, as shown in FIGS. 14 to 16, the first support surface 4a that supports the spacer 20 and the contact region 51a that positions the spacer 20 on the outer periphery E of the bone cut surfaces B1 and B2 of the tibia A may be separated. In the example shown in FIG. 14, by forming two elongated holes 52a extending along the longitudinal direction at the tip of the first member 1, the first support surface 4a that supports the side surface 23 of the spacer 20 and the contact region 51a that contacts the outer periphery E of the tibia A are separated in the width direction X.

[0050] Also, in the example shown in FIG. 15, by forming a U-shaped hole 52b at the tip of the first member 1, the first support surface 4a that supports the side surface 23 of the spacer 20 and the contact region 51a that contacts the outer periphery E of the tibia A are separated. Further, in the example shown in FIG. 16, by forming two slits 52c extending along the longitudinal direction from the tip of the first member 1, the first support surface 4a and the two contact regions 51a that extend in parallel in a fork shape are separated.

[0051] In FIGS. 14 to 16, as shown in FIG. 17, the first support surface 4a and the contact region 51a are respectively formed on the first member 1. By arranging the first support surface 4a and the contact region 51a that are separated from each other in the width direction X on the same plane, the side surface 23 of the spacer 20 can be positioned at a position that coincides with the outer periphery E of the tibia A.

[0052] Alternatively, the first support surface 4a and the contact region 51a may be constituted by separate members. For example, as shown in FIG. 18, a first gripping portion 4 having the first support surface 4a is provided at the tip of the first member 1, and a third member 51 having the contact region 51a may be fixed to the first gripping portion 4, or detachably fixed. Also by this, the first support surface 4a and the contact region 51a can be arranged on the same plane.

[0053] When the first gripping portion 4 having the first support surface 4a and the third member 51 having the contact region 51a are detachably fixed by separate members, as shown in FIG. 19, a third member 51 whose first support surface 4a and contact region 51a can be arranged on different planes may be selected. In the example shown in FIG. 19, the contact region 51a is arranged closer to the second gripping portion 7 than the first support surface 4a.

[0054] By doing so, the side surface 23 of the spacer 20 can be arranged at a position protruding from the outer surface of the tibia A. Thereby, when a spacer 20 having a high-strength portion and a low-strength portion is used, the high-strength portion can be surely sandwiched between the hard cortical bones, and adjustments such as installing the low-strength portion so as to fit inside the cortical bone can be made.

[0055] Also, as shown in FIGS. 20 and 21, the first gripping portion 4 may be provided with a ridge having the first support surface 4a at the center in the width direction of the tip portion having the contact region 51b. Thereby, a contact region 51b that protrudes in the width direction X from the side surface 23 of the spacer 20 being gripped and can contact the outer surface of the tibia A can be arranged at a position on the side opposite to the second gripping portion 7 with respect to the first support surface 4a that supports the spacer 20.

[0056] In this case, as shown in FIG. 21, the first support surface 4a is smaller than the width α of the side surface 23 of the spacer 20 over the entire length from the tip to the base end of the first member 1, and has a width dimension that can be inserted between the bone cutting surfaces B1 and B2 together with the spacer 20. Even with such a configuration, the spacer 20 can be gripped and inserted between the bone cutting surfaces B1 and B2, and the spacer 20 can be arranged in a state of being accurately positioned with respect to the outer periphery E of the bone cutting surfaces B1 and B2 of the tibia A.

[0057] In FIGS. 20 and 21, the first gripping portion 4 is provided with a first support surface 4a for gripping the spacer 20 and a contact region 51b that contacts the outer surface of the tibia A. Instead of this, as shown in FIGS. 22 and 23, the first gripping portion 4 having the first support surface 4a may be separately arranged at a position closer to the second gripping portion 7 than the portion having the contact region 51b of the first member 1. In the examples shown in FIGS. 22 and 23, the width W1 of the first gripping portion 4 is made smaller than the width α of the side surface 23 between the surfaces 21 and 22 over the entire length from the tip to the base end of the first gripping portion 4 so that it can be inserted between the osteotomy surfaces B1 and B2.

[0058] Also, the portion having the contact region 51b is made larger than the width α of the side surface 23 between the surfaces 21 and 22 over the entire length from the tip to the base end and is inserted outside the tibia A along the outer surface of the tibia A. When inserting the spacer 20 between the osteotomy surfaces B1 and B2, the first gripping portion 4 and the second gripping portion 7 sandwiching the spacer 20 are inserted between the osteotomy surfaces B1 and B2, and the contact region 51b is aligned with the outer periphery E of the osteotomy surfaces B1 and B2 of the tibia A. Thereby, even if the spacer 20 has a shape different from that of the spacer 20 for OWHTO having an outer peripheral shape that substantially matches the anatomical shape of the outer periphery E of the inner rear portion D of the osteotomy surfaces B1 and B2, it can be inserted in a state accurately positioned with respect to the outer surface of the tibia A.

[0059] In FIG. 2(a) and the like, the case where the first gripping portion 4 is larger than the width α of the side surface 23 between the surfaces 21 and 22 over the entire length from the tip to the base end is illustrated. Instead of this, as shown in FIG. 24, the dimension W1 in the width direction X of the first gripping portion 4 may be configured to be larger than the width α at one or more positions from the tip to the base end.

[0060] Further, in the present embodiment, the first member 1 includes the first handle portion 5, and the second member 2 includes the second handle portion 8. However, either one of the handle portions 5 and 8 may be omitted. For example, the second handle portion 8 may be omitted by detachably attaching the second gripping portion 7 to the first handle portion 5. Further, the first handle portion 5 may be omitted by detachably attaching the first gripping portion 4 to the second handle portion 8. Furthermore, neither the first member 1 nor the second member 2 has the handle portions 5 and 8, and the first gripping portion 4 and the second gripping portion 7 may be detachably attached to a separate handle member (not shown).

[0061] Next, the spacer insertion instrument 200 according to the second embodiment of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the portions having the same configuration as the spacer insertion instrument 100 according to the first embodiment, and the description thereof will be omitted.

[0062] The spacer insertion instrument 200 according to the present embodiment mainly differs from the spacer insertion instrument 100 according to the first embodiment in the second member 202. As shown in FIGS. 25(a) and 25(b), the second member 202 of the spacer insertion instrument 200 according to the present embodiment has a second gripping portion 207 formed in a wedge shape that tapers toward the tip. That is, the second gripping portion 207 includes inclined surfaces (opening mechanism) 207a formed by planes that are inclined in a direction approaching each other in the width direction X toward the tip on both sides in the width direction X of the spacer insertion instrument 200.

[0063] The angle between the inclined surfaces 207a may be equal to the angle θ between the first surface 21 and the second surface 22 of the spacer 20 sandwiched between the first gripping portion 204 and the second gripping portion 207. Further, the distance between the two inclined surfaces 207a at each position in the length direction Y is set to be equal to or greater than the distance between the first surface 21 and the second surface 22 of the spacer 20 held in a sandwiched state between the first gripping portion 204 and the second gripping portion 207.

[0064] Further, the second member 202 is provided with a portion 208c that can be struck with a hammer at the proximal end of the second handle portion 208. The portion 208c is formed, for example, by curving the proximal end of the second handle portion 8 by approximately 90°.

[0065] Further, the second member 202 is provided with a narrow portion 207b having a dimension in the width direction X that is sufficiently smaller than the distance between the inclined surfaces 207a at the proximal end side of the second gripping portion 207 that contacts the side surface 23 of the spacer 20. Then, in a state where the spacer 20 is gripped, a window portion 201a that penetrates the first member 201 in the plate thickness direction is provided in the first member 201 at a position corresponding to the narrow portion 207b in the height direction Z. The window portion 201a enables the narrow portion 207b of the second member 202 to be visually recognized when viewed in the height direction Z from the first member 201 side. Thereby, the window portion 201a enables the position of the side surface 23 on the proximal end side of the spacer 20 gripped between the first member 201 and the second member 202 to be visually recognized under fluoroscopy.

[0066] Further, in the present embodiment, as shown in FIG. 25(a), the first member 201 is provided with notches 204b that recess both ends in the width direction of the first gripping portion 204 at a position corresponding to the side surface 23b on the distal end side of the spacer 20 gripped between the first member 201 and the second member 202. The notches 204b are arranged outside the inclined surface 207a of the second member 202 in the width direction X when the first member 201 is viewed in the height direction Z. Thereby, the position of the side surface 23b on the distal end side of the spacer 20 can be visually recognized under fluoroscopy.

[0067] A method of using the spacer insertion instrument 200 according to the present embodiment configured as described above will be described below. In OWHTO, an osteotomy of the bone end portion of the tibia A is performed from the inner side surface to the outer side with a bone saw. Next, as shown in Fig. 26(a), the tip of the wedge-shaped second gripping portion 207 provided on the second member 202 of the spacer insertion instrument 200 while gripping the spacer 20 is directed between the bone cut surfaces B1 and B2. At this time, the second gripping portion 207 is inserted into the bone cut portion C between the bone cut surfaces B1 and B2, and the first gripping portion 204 is inserted outside the tibia A. The first gripping portion 204 advances along the outer surface of the tibia A while moving a soft tissue F such as the medial collateral ligament (MCL) away from the tibia A, and the tip portion 41 is disposed on the rear side of the tibia A.

[0068] Then, by hitting the struck portion 208c provided at the proximal end of the second handle portion 208 with a hammer, the second gripping portion 207 is driven between the bone cut surfaces B1 and B2 by the impact of the hammer. Since the second gripping portion 207 is provided with two inclined surfaces 207a that gradually expand from the tip toward the proximal end, as shown in Fig. 26(b), as the insertion of the second gripping portion 207 between the bone cut surfaces B1 and B2 progresses, the space between the bone cut surfaces B1 and B2 is expanded.

[0069] As the second gripping portion 207 is inserted between the bone cut surfaces B1 and B2, the spacer 20 gripped between the first gripping portion 204 and the second gripping portion 207 is also inserted between the bone cut surfaces B1 and B2. In this case, since the distance between the inclined surfaces 207a is set to be equal to or greater than the width of the spacer 20 at each position in the longitudinal direction of the second member, the spacer 20 is prevented from being rubbed against the bone cut surfaces B1 and B2 when inserted. As a result, the spacer 20 can be inserted between the bone cut surfaces B1 and B2 while remaining in a sound state. The subsequent procedure is the same as that shown in Figs. 8(b) to 8(d).

[0070] Thus, according to the present embodiment, similar to the first embodiment, in addition to being able to accurately and easily place the spacer 20 in the bone cut portion C, the bone cut surfaces B1 and B2 can be expanded and the spacer 20 can be inserted without using a separate expander. In addition, according to the present embodiment, since the window portion 201a is provided in the first member 201, the position of the spacer 20 inside the tibia A can be easily confirmed under fluoroscopy. Further, since the notch 204b is provided in the second member 202, the position of the side surface 23b on the tip side of the spacer 20 can be easily confirmed under fluoroscopy.

[0071] In the present embodiment, the opening mechanism including the inclined surface 207a is provided in the second gripping portion 207. In addition to this, as shown in FIG. 27, an opening portion having an inclined surface 204a having the same shape as the inclined surface 207a may be provided on the surface of the first gripping portion 204 on the side of the second gripping portion 207. Since the bone cutting surfaces B1 and B2 are opened by the inclined surfaces 204a and 207a on both sides in the height direction Z of the spacer 20, the spacer 20 can be more reliably protected and inserted into the bone cutting portion C.

[0072] In each of the above embodiments, the case where the first member 1 and the second member 2 are directly attached is exemplified. Instead of this, another member may be interposed therebetween, and the first member 1 and the second member 2 may be indirectly attached.

[0073] As described above, the embodiments of the present invention and their modified examples have been described. However, the present invention is not limited to this, and can be appropriately changed without departing from the gist of the present invention. For example, the second gripping portion 7 does not necessarily have to be flat, and may have another shape as long as the second gripping portion 7 can contact the first side surface 23a. The use of the spacer insertion instrument is not limited to OWHTO for inserting the spacer 20 having an anatomical shape into the bone cutting portion C, and the spacer insertion instrument may be used in other bone surgeries that require the side surface of the spacer to coincide with the outer periphery of the bone cutting surface.

Explanation of reference numerals

[0074] 1 First member 2 Second member 3 Connecting mechanism 4 First gripping portion 4a First support surface 41 Tip 42 Base end part (bending part) 5 First handle part 7 Second gripping part 7a Second support surface 8 Second handle part 9 Connecting member (connecting mechanism) 10 Elastic member (connecting mechanism) 13 Guide mechanism 13a Protrusion (guide mechanism) 13b Guide groove (guide mechanism) 13c, 13d Guide pieces (guide mechanism) 16 Fixing screw (connecting mechanism) 20 Spacer 21 First surface 22 Second surface 23 Side surface 23a First side surface 23b Second side surface 23c Third side surface 100, 101 Spacer insertion instrument A Tibia B1, B2 Bone cut surface C Bone cutting part D Medial posterior part

Claims

1. A spacer insertion instrument for inserting a spacer into a bone cut formed in a bone, wherein the spacer has a first surface and a second surface that face each other and are respectively disposed along a first bone cut surface and a second bone cut surface of the bone cut, and a side surface that connects the first surface and the second surface. A first member having a first gripping portion. A second member attached to the first member and having a second gripping portion. The first gripping portion and the second gripping portion face each other and grip the spacer on the side surface. The first member has a first support surface on the second gripping portion side that supports the side surface of the first gripping portion, and a contact region that is disposed outside the width direction of the side surface of the spacer being gripped and can contact the outer surface of the bone. The spacer insertion instrument.

2. The first gripping portion has a width larger than the width between the first surface and the second surface of the side surface, and is inserted outside the bone. The second gripping portion has a width smaller than the width of the side surface and is inserted into the bone cut. The contact region is provided on the first support surface on the second gripping portion side that supports the side surface of the first gripping portion. The spacer insertion instrument according to Claim 1.

3. The first gripping portion and the second gripping portion have a width smaller than the width between the first surface and the second surface of the side surface. The spacer insertion instrument according to Claim 1.

4. The spacer is a spacer for a high tibial osteotomy with an inwardly opening type, and a part of the side surface has a shape that substantially conforms to the anatomical shape of the outer periphery of the inner rear portion of the first bone cut surface and the second bone cut surface formed in the tibia. The first gripping portion has a curved portion having a curved shape that substantially conforms to the anatomical shape of the outer periphery of the inner rear portion. The spacer insertion instrument according to Claim 2.

5. The first gripping portion is in the shape of a strip plate and has a dimension larger than that of the spacer in the longitudinal direction of the first member. The tip of the first gripping portion is disposed at a position protruding in the longitudinal direction from the tip of the spacer. The spacer insertion instrument according to any one of Claims 1 to 3.

6. The second gripping portion includes an opening mechanism that opens the gap by being inserted into the gap between the first bone cut surface and the second bone cut surface along the longitudinal direction of the second member from the tip of the second gripping portion. The spacer insertion instrument according to Claim 1.

7. The spacer insertion instrument according to claim 6, wherein the opening mechanism includes two surfaces that gradually approach each other in the width direction of the second gripping portion from the proximal end side toward the distal end side.

8. The spacer insertion instrument according to any one of claims 1 to 3, further comprising a connection mechanism that connects the first gripping portion and the second gripping portion so as to be movable in the longitudinal direction of the first member or separable from each other.

9. The connection mechanism connects the first gripping portion and the second gripping portion such that the second member is movable in the longitudinal direction between a first position and a second position with respect to the first member, The first position is a position where the second gripping portion faces the first gripping portion and can grip the spacer, The spacer insertion instrument according to claim 8, wherein the second position is a position where the distal end of the second gripping portion is disposed at or near the proximal end of the first gripping portion and releases the spacer.

10. The spacer insertion instrument according to claim 7, further comprising a guide mechanism that restricts the moving direction of the second gripping portion with respect to the first gripping portion to the longitudinal direction.

11. The first gripping portion has a flat distal end portion, The spacer insertion instrument according to any one of claims 1 to 3, wherein the first member includes a first handle portion that extends parallel or substantially parallel to the distal end portion.

12. The second support surface on the first gripping portion side that supports the side surface of the second gripping portion is inclined with respect to the first gripping portion in a direction approaching the first gripping portion toward the distal end.

13. The spacer insertion instrument according to any one of claims 1 to 3, wherein the first gripping portion has an anti-slip portion that prevents the spacer from slipping with respect to the first support surface in a region where the side surface of the spacer contacts the first support surface.

14. The spacer insertion instrument according to any one of claims 1 to 3, wherein the second gripping portion is capable of fitting into a groove formed in the side surface of the spacer.

15. A spacer insertion instrument for inserting a spacer into an osteotomy formed in a bone, the spacer having a first surface and a second surface that face each other and are respectively disposed along a first osteotomy surface and a second osteotomy surface of the osteotomy, and a side surface that connects the first surface and the second surface, A first member having a first gripping portion, A second member attached to the first member and having a second gripping portion, and a third member fixed to the first gripping portion. The first gripping portion and the second gripping portion face each other and grip the spacer on the side surface. The first gripping portion has a first support surface on the second gripping portion side that supports the side surface. The third member is disposed outside the spacer in the width direction of the side surface being gripped and has a contact region capable of contacting the outer surface of the bone, and is a spacer insertion instrument.

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