JP2024132994A - Spacer Insertion Tool - Google Patents

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

The present invention relates to a spacer insertion device.

Conventionally, large open medial high tibial osteotomy (OWHTO) has been performed as a treatment for correcting the load biased to the medial side due to bow leg deformity caused by osteoarthritis of the knee, etc. As shown in Fig. 11(c) , in OWHTO, a spacer 30 such as an artificial bone is inserted into a wedge-shaped osteotomy C between the bone cut surfaces B1 and B2. A typical wedge-shaped spacer 30 is placed in the anterior and posterior parts of the osteotomy C.
In bone surgeries including such HTO, instruments for grasping bones are used (see, for example, Patent Documents 1 to 3).

Patent No. 6400420 Patent No. 3130560 Patent No. 4966861

As shown in Figs. 12(a)-(e) and 13, a new spacer 20 for OWHTO has been proposed, which has an outer peripheral shape that approximately matches the anatomical shape of the outer peripheral shape E of the inner posterior part D of the osteotomy surfaces B1 and B2. The spacer 20 needs to be placed in the osteotomy C so that the side surface 23c having the outer peripheral shape matches the outer peripheral shape E of the inner posterior part D. However, it is difficult to accurately place the spacer 20 in such a position through a small incision made in the skin.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a spacer insertion tool that can accurately and easily place a spacer in the osteotomy so that the side surface of the spacer coincides with the outer periphery of the osteotomy surface.

One aspect of the present invention is a spacer insertion tool 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 arranged along the first and second osteotomy surfaces of the osteotomy, respectively, and a side surface that connects the first surface and the second surface, a first member having a first gripping portion at the tip side and a first handle portion at the base end, and a second member having a second gripping portion at the tip side and a second handle portion at the base end, the first gripping portion and the second gripping portion face each other and grip the spacer at the side surface, the first gripping portion has a width larger than the width between the first and second surfaces 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 osteotomy, and the first support surface on the second gripping portion side that supports the side surface of the first gripping portion protrudes from the side surface in the width direction of the side surface and has a contact area that can come into contact with the outer surface of the bone.

The present invention has the advantage that the spacer can be accurately and easily positioned in the osteotomy so that the side surface of the spacer coincides with the outer periphery of the osteotomy surface.

1A and 1B are assembly views of a spacer insertion tool according to a first embodiment of the present invention, in which (a) is a plan view and (b) is a side view showing a state in which a second member is disposed in a first position. 2A and 2B are diagrams for explaining the operation of the spacer insertion instrument of FIG. 1, in which (a) is a plan view and (b) is a side view in a state in which the second member is disposed at a second position. 1A is a plan view of one example of a first gripping portion, and FIG. 1B is a plan view of another example of a first gripping portion. 2A is a plan view seen from the upper surface side of a first member of the spacer insertion instrument of FIG. 1, and FIG. 2B is a bottom view seen from the lower surface side of the first member. 2A is a side view of a second member of the spacer insertion tool of FIG. 1 , and FIG. 2B is a bottom view of the second member as viewed from the lower surface side. 13 is a side view of an example of a connecting member and an elastic member of the connecting mechanism. FIG. 6A to 6D are diagrams illustrating the fastening and unfastening of a second member by a connecting member and an elastic member. 1A, 1B, 1C, and 1D are diagrams illustrating a method of using the spacer insertion tool. FIG. 13 is an exploded view of a spacer insertion tool according to another embodiment. FIG. 10 is an assembled side view of the spacer insertion tool of FIG. 1A and 1B are diagrams for explaining the OWHTO, in which (a) is a front view of the tibia as seen from the anterior side, and (b) and (c) are side views of the tibia as seen from the medial side. 1A-E are (a) front, (b) top, (c) bottom, (d) left side and (e) right side views of an anatomically shaped spacer. FIG. 13 is a diagram illustrating the inner posterior part of the bone resection surface. 10 is a plan view of another example of the first gripping portion of the spacer insertion tool of FIG. 9 . 10 is a plan view of still another example of the first gripping portion of the spacer insertion tool of FIG. 9 . 10 is a plan view of still another example of the first gripping portion of the spacer insertion tool of FIG. 9 . 10 is a longitudinal sectional view of a first gripping portion of the spacer insertion tool of FIG. 9 . FIG. 18 is a vertical cross-sectional view of another example of the first gripping portion of FIG. 17 . FIG. 18 is a vertical cross-sectional view of yet another example of the first gripping portion of FIG. 17 . FIG. 10 is an assembled side view of the spacer insertion tool of FIG. 10 is a plan view of a second member of the spacer insertion tool of FIG. 9. FIG. 22 is a plan view of another example of the second member of the spacer insertion tool of FIG. 21. FIG. 23 is an assembled side view of the spacer insertion tool of FIG. 22. 10 is a plan view of still another example of the first gripping portion of the spacer insertion tool of FIG. 9 . 13A and 13B are diagrams illustrating the operation of the spacer insertion instrument according to the second embodiment, in which (a) is a plan view and (b) is a side view showing a state in which the second member is disposed at a second position. 26(a) and 26(b) are diagrams illustrating a method of using the spacer insertion tool of FIG. 25. FIG. 26 is an assembled side view of another example of the spacer insertion tool of FIG. 25.

Hereinafter, a spacer insertion tool according to a first embodiment of the present invention will be described with reference to the drawings.
As shown in Figures 11(a) and (b) , the spacer insertion instrument 100 according to this embodiment is used for inserting a spacer 20 such as an artificial bone into a bone cut portion C between bone cut surfaces B1 and B2 formed on the bone end of a tibia A in a medial open large high tibial osteotomy (OWHTO).

The instrument 100 is particularly suited for inserting a spacer 20, shown in Figures 12(a)-(e), into the osteotomy 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.

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 respectively disposed on the anterior and lateral sides of the osteotomy portion C, and the third side surface 23c is disposed on the medial and posterior sides of the osteotomy portion C (see Figs. 8(c) and (d)).

The third side surface 23c is a curved surface that is convex toward the outside and has a curved shape that is approximately the same as the anatomical shape of the outer circumference E of the inner posterior part D of the patient's bone resection surfaces B1 and B2. As shown in FIG. 13, the inner posterior part D is a part that is located inside the first axis Q1 and behind 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 at a first distance d1 (e.g., 28.5 mm or more and 30 mm or less) outward from the medial protruding point P1. The second axis Q2 extends in a direction parallel to the medial-lateral direction of the tibia A and is located at a second distance d2 (22.7 mm or more and 35 mm or less) anterior to the posterior protruding point P2. The medial protruding point P1 is the innermost position of the bone resection surfaces B1 and B2. The posterior protruding point P2 is the posteriormost position of the bone resection surfaces B1 and B2, inside the first axis Q1.

Almost all patients have substantially the same anatomical shape of the outer periphery E of the medial posterior portion D. Therefore, by disposing the spacer 20 in the osteotomy portion C so that the third side surface 23c coincides 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 an accurate correction angle θ, it is necessary to align the third side surface 23c with the outer periphery E of the medial posterior portion D. Meanwhile, soft tissue F including ligaments is present around the tibia A. The spacer insertion tool 100 enables accurate placement of the spacer 20 in the osteotomy portion C while protecting the soft tissue F.

As shown in FIGS. 1 to 5, a spacer insertion tool 100 includes a first member 1, a second member 2, and a connecting mechanism 3 that connects the first member 1 and the second member 2 so as to be movable relative to each other.
Each of the members 1 and 2 is a long strip-like member having a tip and a base end, and extends straight when viewed in a plan view 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.

The two members 1 and 2 are arranged in the thickness direction, with the flat second handle portion 8 being 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 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 perpendicular to the height direction Z and the width direction X is defined as the length direction Y of the instrument 100.

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

The surface 4a of the first gripping portion 4 on the second member 2 side is a first support surface that contacts the third side surface 23c and supports the third side surface 23c. The surface 7a of the second gripping portion 7 on the first member 1 side is a second support surface that contacts the first side surface 23a and supports the first side surface 23a. To improve the fixation 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 on the first side surface 23a (see, for example, FIG. 12(b)).

The first gripping portion 4 has a flat tip portion 41 that includes the tip of the first member 1 , and a base end portion 42 that connects the base end of the tip portion 41 and the tip of the bending portion 6 .
The tip portion 41 is parallel or approximately parallel to the handle portions 5, 8 in a side view in the width direction X. The base portion 42 is curved about an axis in the width direction X so as to be convex toward the opposite side to the second grip portion 7. Therefore, the first member 1 has a generally 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 narrower in the width direction X than the second handle portion 8, the first gripping portion 4, and the first handle portion 5.

3(a) and 3(b), the width W1 of the first gripping portion 4 is greater 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 osteotomy portion C between the bone resection surfaces B1, B2 is approximately the same as the width α of the side surface 23. Therefore, the second gripping portion 7 can be inserted into the osteotomy portion C. Meanwhile, 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 is disposed between the spacer 20 and the soft tissue F surrounding the tibia A and functions as a retractor to protect the soft tissue F.

The first support surface 4a has contact areas 4b that protrude from the side surface 23c in the width direction X on both sides of the third side surface 23c supported by the first support surface 4a. In Figs. 3(a) and (b), the contact areas 4b are shown hatched. The contact areas 4b on both sides can contact the outer surface of the tibia A on the proximal and distal sides of the osteotomy portion C, and the third side surface 23c is made to coincide with the outer periphery E of the osteotomy surfaces B1 and B2 by contacting the contact areas 4b with the outer surface of the tibia A.

In plan view, the first gripping portion 4 may be generally trapezoidal in shape with a width W1 that gradually narrows toward the tip as shown in FIG. 3(a), or generally rectangular in shape with a constant width W1 as shown in FIG. 3(b). In order to make it possible to easily insert the first gripping portion 4 along the outer surface of the tibia A while avoiding interference with the soft tissue F, a narrow first gripping portion 4 as shown in FIG. 3(a) is preferred.

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 less than the length β. The lengths L1 and L2 are the dimensions of the gripping portions 4 and 7 in the longitudinal direction Y (see FIG. 1(b)), and the length β is the maximum dimension of the spacer 20 in the inward-outward direction (see FIG. 12(a)). Therefore, the tip of the first gripping portion 4 is positioned at a position that protrudes in the longitudinal direction Y beyond the second side surface 23b of the tip of the spacer 20.

The first support surface 4a of the tip end 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 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 42, it is preferable that at least a portion of the first support surface 4a of the base end 42 has a curved shape that approximately matches 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 a portion corresponding to the vicinity of the inner protruding point P1, and R2 is the radius of curvature of a portion rearward 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 42 may have two curved portions 42a and 42b with different radii of curvature (see FIG. 1(b) and FIG. 2(b)). For example, it is preferable that the radius of curvature of the first support surface 4a of the first curved portion 42a on the base end side is greater than or equal to 8 mm and less than or equal to 10 mm, and it is preferable that the radius of curvature of the first support surface 4a of the second curved portion 42b on the tip end side is greater than or equal to 20 mm and less than or equal to 22 mm.

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

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

If the width W1 is less than 5 mm, the first gripping portion 4 enters the osteotomy portion C, making it difficult to bring the contact area 4b into contact with the outer surface of the tibia A. If the width W1 is greater than 18 mm, the fit of the contact area 4b to the outer surface of the tibia A decreases, and the gap between the contact area 4b and the outer surface of the tibia A increases.
If 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 the first gripping portion 4 may not effectively function as a retractor. If the length L3 is greater than 30 mm, the tip of the first gripping portion 4 may hit the lateral condyle G (see FIG. 13 ) of the posterior surface of the tibia A, making it difficult to insert the spacer 20 to an appropriate position in the osteotomy portion C.

The connecting mechanism 3 connects the first member 1 and the second member 2 together such that the second member 2 is movable in the longitudinal direction relative to the first member 1 between a first position and a second position.
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 base end and tip of the tip portion 41 (see FIGS. 1(a) and 1(b)). When the second member 2 is disposed at the first position, the pair of gripping portions 4, 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 base end of the first gripping portion 4 (see FIGS. 2(a) and 2(b)). When the second member 2 is disposed at the second position, the pair of gripping portions 4, 7 release the spacer 20.

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, 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 set screw including a male screw 91 having a first head 9b and a female screw 92 having a second head 9c.
The elastic member 10 is, for example, a compression coil spring arranged around the shaft portion 9a.

The first handle portion 5 has a slot 11 that penetrates in the thickness direction and extends in the longitudinal direction (see Figures 4(a) and (b)), and the second handle portion 8 has a hole 12 that penetrates in the thickness direction and communicates with a portion of the slot 11 in the height direction Z (see Figures 5(a) and (b)).
7(a) to 7(d), the shaft portion 9a passes through the slot 11 and the hole 12 so as to be movable in the height direction Z, and the two head portions 9b, 9c are disposed on both sides of the handle portions 5, 8 in the height direction Z. The elastic member 10 is disposed between the first head portion 9b on the second handle portion 8 side and the second handle portion 8, and biases the first head portion 9b and the second handle portion 8 in directions away from each other.

As shown in FIG. 7(a), in the normal state, the biasing force of the elastic member 10 applies a force to the two handle portions 5, 8 in a direction that brings them into close contact with each other, thereby fixing the second member 2 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 first handle portion 5 side presses the first handle portion 5 toward the second handle portion 8.

7(b) and (c), the user presses down the first head 9b on the second handle portion 8 side against the biasing force of the elastic member 10, thereby releasing the second handle portion 8. In the released state, the second member 2 becomes movable between the first position and the second position relative to the first member 1 by the movement of the shaft portion 9a within the slot 11.
After the second member 2 has moved, as shown in FIG. 7( d ), the second member 2 is again fixed to the first member 1 by the biasing force of the elastic member 10 by releasing the first head 9 b .

Next, a method of using the spacer insertion tool 100 will be described.
In OWHTO, the end of the tibia A is cut from the medial surface to the lateral surface with a bone saw, and the area between the cut surfaces B1 and B2 is expanded with a speculum. The bone saw and speculum are inserted into the knee through an incision made in the skin on the medial side of the knee.
8(a), the pair of gripping parts 4, 7 holding the spacer 20 are inserted into the knee from the incision, and the spacer 20 is inserted from the inside to the outside into the osteotomy part C while aligning the first surface 21 and the second surface 22 along the bone resection surfaces B1, B2, respectively. At this time, the second gripping part 7 is inserted into the osteotomy part C between the bone resection surfaces B1, B2, and the first gripping part 4 is inserted outside the tibia A. The first gripping part 4 advances along the outer surface of the tibia A while moving soft tissue F such as the medial collateral ligament (MCL) away from the tibia A, and the tip part 41 is positioned on the posterior side of the tibia A.

8(b), the first support surfaces 4a of the distal end 41 and proximal end 42, which are located on the rear and medial sides of the tibia A, respectively, are abutted against the outer surface of the medial posterior part D of the tibia A. As a result, the contact areas 4b of the distal end 41 and proximal end 42 come into contact with the outer surface of the tibia A on the distal and proximal sides of the osteotomy C, and the spacer 20 is positioned so that the third side surface 23c coincides with the outer periphery E of the medial posterior part D of the osteotomy surfaces B1 and B2.

After the spacer 20 is positioned, the expansion of the osteotomy portion C by the expander is released.
8C, the second member 2 is released by pressing down the first head 9b, and the second member 2 is slid to the second position, thereby releasing the spacer 20 from the gripping portions 4 and 7.
Next, as shown in FIG. 8( d ), the first member 1 is pulled out from between the tibia A and the soft tissue F while being rotated forward.

Thus, according to this embodiment, the first support surface 4a supporting the third side surface 23c has the contact areas 4b on both sides of the third side surface 23c in the width direction. Therefore, by simply bringing the contact areas 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 aligned with the outer periphery E of the inner rear portion D of the bone resection surfaces B1 and B2. This allows the spacer 20 to be accurately and easily positioned in the osteotomy portion C.
In particular, it is difficult to visually observe through the incision in the skin a rear portion of the third side surface 23c disposed on the rear side of the tibia A. According to this embodiment, the rear portion of the third side surface 23c can be easily aligned with the outer periphery E simply by bringing the contact area 4b of the tip portion 41 on the rear side of the tibia A into contact with the rear surface of the tibia A.

In addition, according to this embodiment, the first gripping portion 4 inserted between the tibia A and the soft tissue F functions as a retractor that protects the soft tissue F. Therefore, using only the instrument 100, the spacer 20 can be inserted into the osteotomy portion C while protecting the soft tissue F around the tibia A. In particular, when the spacer 20 is inserted into the osteotomy portion C, the tip of the first gripping portion 4 is positioned in front of the spacer 20, thereby effectively protecting the soft tissue F.

In addition, according to this embodiment, the first handle portion 5 is parallel or approximately parallel to the tip portion 41. During surgery, the surgeon cannot see the tip portion 41 inside the knee. Because the first handle portion 5 is parallel or approximately parallel to the tip portion 41, the surgeon can recognize the direction of the tip portion 41 inside the knee based on the direction of the first handle portion 5, and can appropriately adjust the direction of the first grip portion 4 inside the knee so that the first grip portion 4 is positioned in the medial-lateral direction of the tibia A.

In the above embodiment, the support surface 4a of the base end 42 is in contact with the third side surface 23c, but the support surface 4a of the base end 42 does not necessarily have to be in contact with the third side surface 23c. That is, it is sufficient for the first gripping portion 4 to be in contact with the third side surface 23c at least at the support surface 4a of the tip end 41, and the base end 42 may have any shape.
The medial portion of the third side surface 23c, which is disposed on the medial side of the tibia A, can be seen through the skin incision. Thus, the posterior portion of the third side surface 23c can be aligned to the periphery E using the contact area 4b of the tip 41, and the medial portion of the third side surface 23c can be aligned to the periphery E by visual inspection.

In the above embodiment, it is preferable that the spacer insertion device 100 further includes a guide mechanism 13 that restricts the movement direction of the second handle portion 8 relative to the first handle portion 5 in the longitudinal direction Y. By providing the guide mechanism 13, the second member 2 can be slid straight in the longitudinal direction Y relative to the first member 1 without wobbling in the width direction X.

An example of the guide mechanism 13 has a convex portion 13a and a guide groove 13b that receives the convex portion 13a in the height direction Z. As shown in Figures 5(a) and (b), the convex portion 13a is provided on the lower surface 8b of the second handle portion 8 on the first handle portion 5 side, and protrudes from the lower surface 8b in the height direction Z. As shown in Figures 4(a) and (b), the guide groove 13b is provided on the upper surface 5a of the first handle portion 5 on the second handle portion 8 side, and extends linearly in the length direction Y. The width of the guide groove 13b is approximately equal to the width of the convex portion 13a, and the movement of the convex portion 13a in the guide groove 13b is limited only in the length direction Y.
The arrangement of the protrusion 13a and the guide groove 13b may be reversed, i.e., the protrusion 13a may be provided on the upper surface 5a, and the guide groove 13b may be provided on the lower surface 8b.

In the above embodiment, in order to improve the gripping force of the gripping portions 4, 7 on the spacer 20, the second support surface 7a may be inclined in a direction gradually approaching the first support surface 4a toward the tip.
5A, the inclination of the second support surface 7a relative to the first support surface 4a may be formed by a wedge-shaped protrusion 13a that becomes thinner toward the tip in the height direction Z. With this configuration, the gripping force can be increased without adding any member to the gripping parts 4, 7 that are inserted into the knee.

In the above embodiment, the first gripping portion 4 preferably has a slip prevention member 17 for preventing the spacer 20 from slipping on the first support surface 4a. The slip prevention member 17 is provided in the area of the first support surface 4a that contacts the spacer 20 (see, for example, FIG. 1(a) and FIG. 2(a)). The slip prevention member 17 may be composed of a fine uneven 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 against a force in the width direction X. In order to increase the stability in the width direction X, the uneven structure may be composed of a plurality of convex portions extending parallel to each other in the length direction Y.

In the above embodiment, the second member 2 is released from its fixed position relative to the first member 1 by a one-touch operation of pressing the connecting member 9. Alternatively, the second member 2 may be releasably fixed to the first member 1 by a fixing member such as a screw.
9 and 10 show a spacer insertion instrument 101 according to another embodiment. The first member 1 has a threaded 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 longitudinal direction Y. The coupling mechanism 3 of the instrument 101 has a fixing screw 16 that passes through the slot 15 and is inserted into the threaded hole 14. 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 released and becomes movable in the longitudinal direction Y.

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

In the above embodiment, the connecting mechanism 3 connects the two members 1, 2 to be relatively movable in the longitudinal direction Y, but instead, the two members 1, 2 may be connected to each other so as to be separable from each other. For example, the connecting mechanism may removably fix the second member 2 to the first member 1 by a fixing member such as a screw. After the spacer 20 is placed in the osteotomy portion C, the second member 2 is removed from the first member 1 to release the spacer 20.
In this way, when the two members 1, 2 are not moved relatively in the longitudinal direction Y, the handle portions 5, 8 do not necessarily need to be straight and flat, but may be curved.

In the above embodiment, the first member 1 and the second member 2 are separate members, but instead, the first member and the second member may be composed of a single member. For example, the first member and the second member may be connected to each other at their base ends, and the spacer insertion tool may have a shape similar to tweezers.

In the above embodiment, in order to confirm the direction of the gripping parts 4, 7 in the knee from outside the body, the gripping parts 4, 7 may have a marker that is visible under X-ray fluoroscopy and indicates the direction of the gripping parts 4, 7. For example, the marker may be a protrusion provided at the tip of the gripping parts 4, 7, or a thick part provided along the center line of the gripping parts 4, 7.

In this embodiment, the spacer insertion instrument 100 is illustrated, which 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. The width W1 of the first gripping portion 4 is made larger than the width α of the side surface 23 at each position along the entire length of the first gripping portion 4 from the tip to the base end, and the first support surface 4a is provided with a contact area 4b that can contact the outer surface of the tibia A on the proximal and distal sides of the osteotomy portion C. In other words, the first support surface 4a of the first gripping portion 4 is given both the function of supporting the spacer 20 and the function of matching 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, thereby making the first member 1 compact.

Alternatively, as shown in Figures 14 to 16, the first support surface 4a that supports the spacer 20 and the contact area 51a that positions the spacer 20 on the outer periphery E of the osteotomy surfaces B1, B2 of the tibia A may be separated. In the example shown in Figure 14, two elongated holes 52a extending along the longitudinal direction are formed at the tip of the first member 1, so that the first support surface 4a that supports the side surface 23 of the spacer 20 and the contact area 51a that contacts the outer periphery E of the tibia A are separated in the width direction X.

In the example shown in FIG. 15, a U-shaped hole 52b is formed at the tip of the first member 1, separating the first support surface 4a that supports the side surface 23 of the spacer 20 from the contact area 51a that contacts the outer periphery E of the tibia A. In the example shown in FIG. 16, two slits 52c are formed extending from the tip of the first member 1 in the longitudinal direction, separating the first support surface 4a that extends in parallel in a fork shape from the two contact areas 51a.

In these Figures 14 to 16, as shown in Figure 17, the first support surface 4a and the contact area 51a are formed on the first member 1. By arranging the first support surface 4a and the contact area 51a, which 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.

Alternatively, the first support surface 4a and the contact area 51a may be formed by separate members. For example, as shown in FIG. 18, a first gripping part 4 having a first support surface 4a may be provided at the tip of the first member 1, and a third member 51 having a contact area 51a may be fixed or detachably fixed to the first gripping part 4. This also allows the first support surface 4a and the contact area 51a to be arranged on the same plane.

When the first gripping part 4 having the first support surface 4a and the third member 51 having the contact area 51a are detachably fixed by separate members, a third member 51 that allows the first support surface 4a and the contact area 51a to be arranged on different planes may be selected, as shown in FIG. 19. In the example shown in FIG. 19, the contact area 51a is arranged closer to the second gripping part 7 than the first support surface 4a.

In this way, the side surface 23 of the spacer 20 can be positioned so that it protrudes from the outer surface of the tibia A. This allows adjustments to be made so that when a spacer 20 having a high strength portion and a low strength portion is used, the high strength portion is securely sandwiched between the hard cortical bones, and the low strength portion is positioned inside the cortical bone.

20 and 21, the first gripping portion 4 may have a protrusion having a first support surface 4a at the center in the width direction of the tip portion having the contact area 51b. This allows the contact area 51b, which protrudes in the width direction X from the side surface 23 of the gripped spacer 20 and can contact the outer surface of the tibia A, to be located on the opposite side of the second gripping portion 7 from the first support surface 4a that supports the spacer 20.

As shown in FIG. 21, the first support surface 4a in this case has a width dimension that 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 can be inserted between the bone resection surfaces B1 and B2 together with the spacer 20. Even with this configuration, the spacer 20 can be grasped and inserted between the bone resection surfaces B1 and B2, and the spacer 20 can be positioned with high precision relative to the outer periphery E of the bone resection surfaces B1 and B2 of the tibia A.

20 and 21, the first gripping part 4 is provided with a first support surface 4a for gripping the spacer 20 and a contact area 51b for contacting the outer surface of the tibia A. Alternatively, as shown in FIGS. 22 and 23, a first gripping part 4 having a first support surface 4a may be separately disposed at a position closer to the second gripping part 7 than the part of the first member 1 having the contact area 51b. In the example shown in FIGS. 22 and 23, the width W1 of the first gripping part 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 part 4, so that it can be inserted between the bone resection surfaces B1 and B2.

In addition, the portion having the contact area 51b is inserted outside the tibia A along the outer surface of the tibia A, with the entire length from the tip to the base end being larger than the width α of the side surface 23 between the surfaces 21 and 22.
When inserting the spacer 20 between the bone resection surfaces B1, B2, the first gripping portion 4 and the second gripping portion 7 sandwiching the spacer 20 are inserted between the bone resection surfaces B1, B2, and the contact area 51b is made to coincide with the outer periphery E of the bone resection surfaces B1, B2 of the tibia A. This allows the spacer 20 to be inserted in a state where it is accurately positioned relative to the outer surface of the tibia A, even if the spacer 20 has a shape different from the spacer 20 for OWHTO, which has an outer periphery shape that approximately coincides with the anatomical shape of the outer periphery E of the medial rear part D of the bone resection surfaces B1, B2.

2(a) and other figures show an example in which 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. Alternatively, as shown in FIG. 24, the dimension W1 of the first gripping portion 4 in the width direction X may be configured to be larger than the width α at one or more points from the tip to the base end.

In addition, in this embodiment, the first member 1 includes the first handle portion 5 and the second member 2 includes the second handle portion 8, but either one of the handle portions 5, 8 may be omitted. For example, the second handle portion 8 may be omitted by removably attaching the second grip portion 7 to the first handle portion 5. Also, the first handle portion 5 may be omitted by removably attaching the first grip portion 4 to the second handle portion 8. Furthermore, neither the first member 1 nor the second member 2 may have the handle portions 5, 8, and the first grip portion 4 and the second grip portion 7 may be removably attached to separate handle members (not shown).

Next, a spacer insertion device 200 according to a second embodiment of the present invention will be described below with reference to the drawings. In the description of this embodiment, parts that have the same configuration as the spacer insertion device 100 according to the first embodiment will be given the same reference numerals and will not be described.

The spacer insertion tool 200 according to this embodiment differs from the spacer insertion tool 100 according to the first embodiment mainly in a second member 202 .
25(a) and 25(b), the second member 202 of the spacer insertion instrument 200 according to this embodiment has a second gripping portion 207 formed in a wedge shape tapered toward the tip. That is, the second gripping portion 207 has inclined surfaces (opening mechanisms) 207a on both sides in the width direction X of the spacer insertion instrument 200, the inclined surfaces being flat surfaces that incline toward each other in the width direction X toward the tip.

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. In addition, the distance between the two inclined surfaces 207a at each position in the longitudinal 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 when it is sandwiched and held between the first gripping portion 204 and the second gripping portion 207.

The second member 202 also has a striking portion 208c at the base end of the second handle portion 208 that can be struck with a hammer. The striking portion 208c is formed, for example, by bending the base end of the second handle portion 8 by approximately 90°.

The second member 202 also has a narrow portion 207b, the dimension of which in the width direction X is sufficiently smaller than the distance between the inclined surfaces 207a, on the base end side of the second gripping portion 207 that contacts the side surface 23 of the spacer 20. When the spacer 20 is gripped, the first member 201 at a position corresponding to the narrow portion 207b in the height direction Z is provided with a window portion 201a penetrating the first member 201 in the plate thickness direction. The window portion 201a makes the narrow portion 207b of the second member 202 visible when viewed in the height direction Z from the first member 201 side. As a result, the window portion 201a makes it possible to visually check the position of the side surface 23 on the base end side of the spacer 20 gripped between the first member 201 and the second member 202 under X-ray fluoroscopy.

In addition, in this embodiment, as shown in FIG. 25(a), the first member 201 has notches 204b recessed at both ends in the width direction of the first gripping portion 204 at positions corresponding to the side surface 23b at the tip end of the spacer 20 gripped between the first member 201 and the second member 202. When the first member 201 is viewed in the height direction Z, the notches 204b are positioned further outward in the width direction X than the inclined surface 207a of the second member 202. This allows the position of the side surface 23b at the tip end of the spacer 20 to be visually confirmed under X-ray fluoroscopy.

A method of using the spacer insertion tool 200 according to this embodiment configured as described above will be described below.
In OWHTO, the epiphysis of the tibia A is cut from the medial surface to the lateral surface with a bone saw.
26(a), the tip of a wedge-shaped second gripping portion 207 provided on the second member 202 of the spacer insertion tool 200 gripping the spacer 20 is placed between the bone resection surfaces B1 and B2. At this time, the second gripping portion 207 is inserted into the bone resection portion C between the bone resection 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 soft tissue F such as the medial collateral ligament (MCL) away from the tibia A, and the tip portion 41 is positioned on the posterior side of the tibia A.

Then, the striking portion 208c provided at the base end of the second handle portion 208 is struck with a hammer, and the impact of the hammer drives the second gripping portion 207 between the bone resection surfaces B1, B2. The second gripping portion 207 has two inclined surfaces 207a that gradually widen from the tip to the base end, so that as the insertion of the second gripping portion 207 between the bone resection surfaces B1, B2 progresses, the gap between the bone resection surfaces B1, B2 is widened as shown in FIG. 26(b).

As the second gripping portion 207 is inserted between the bone resection surfaces B1 and B2, the spacer 20 held between the first gripping portion 204 and the second gripping portion 207 is also inserted between the bone resection surfaces B1 and B2. In this case, 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, so that the spacer 20 is prevented from rubbing against the bone resection surfaces B1 and B2 when inserted. This allows the spacer 20 to be inserted between the bone resection surfaces B1 and B2 while remaining in a healthy state. The subsequent steps are the same as those shown in Figures 8(b) to 8(d).

Thus, according to this embodiment, as in the first embodiment, the spacer 20 can be accurately and easily positioned in the osteotomy portion C, and in addition, the bone resection surfaces B1, B2 can be opened and the spacer 20 can be inserted without using a separate expander.
According to this embodiment, since the first member 201 has the window portion 201a, the position of the spacer 20 on the inside of the tibia A can be easily confirmed under X-ray fluoroscopy. Since the second member 202 has the notch 204b, the position of the side surface 23b on the tip side of the spacer 20 can be easily confirmed under X-ray fluoroscopy.

In this embodiment, the second gripping part 207 is provided with an opening mechanism consisting of the inclined surface 207a. In addition, as shown in FIG. 27, an opening part having an inclined surface 204a of the same shape as the inclined surface 207a may be provided on the surface of the first gripping part 204 facing the second gripping part 207. The inclined surfaces 204a and 207a open the bone resection surfaces B1 and B2 on both sides of the height direction Z of the spacer 20, so that the spacer 20 can be inserted into the bone resection C while being protected more reliably.

In addition, in each of the above embodiments, the first member 1 and the second member 2 are directly attached to each other, but instead, the first member 1 and the second member 2 may be indirectly attached to each other by interposing another member therebetween.

Although the embodiment of the present invention and its modified examples have been described above, the present invention is not limited to this and can be modified as appropriate 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 tool is not limited to OWHTO, in which a spacer 20 having an anatomical shape is inserted into an osteotomy portion C, but the spacer insertion tool may also be used in other bone surgeries in which the side of the spacer needs to be matched to the outer periphery of the osteotomy surface.

REFERENCE SIGNS LIST 1 First member 2 Second member 3 Connecting mechanism 4 First gripping portion 4a First support surface 41 Tip portion 42 Base end portion (curved portion)
5 First handle portion 7 Second grip portion 7a Second support surface 8 Second handle portion 9 Connecting member (connecting mechanism)
10 Elastic member (connecting mechanism)
13 Guide mechanism 13a Convex portion (guide mechanism)
13b Guide groove (guide mechanism)
13c, 13d Guide piece (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 tool A Tibia B1, B2 Bone cutting surface C Bone cutting portion D Medial posterior portion

Claims (14)

A spacer insertion tool for inserting a spacer into an osteotomy portion formed in a bone, the spacer having a first surface and a second surface opposed to each other and respectively disposed along a first bone resection surface and a second bone resection surface of the osteotomy portion, and a side surface connecting 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 at the side surface;
A spacer insertion tool having a first support surface on the second gripping portion side that supports the side surface of the first gripping portion, and a contact area that is positioned outside the width direction of the side surface of the spacer being gripped and is capable of contacting the outer surface of the bone. The first gripping portion has a width greater than a 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 osteotomy portion;
The spacer insertion tool according to claim 1 , wherein the contact area is provided on the first support surface of the second gripping portion that supports the side surface of the first gripping portion. The spacer insertion tool according to claim 1, wherein 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 is a spacer for a medial open large high tibial osteotomy, and a portion of the side surface has a shape that is approximately the same as an anatomical shape of an outer periphery of an inner posterior portion of the first osteotomy surface and the second osteotomy surface formed on the tibia,
The spacer insertion tool of claim 2 , wherein the first gripping portion has a curved portion having a curved shape that generally matches an anatomical shape of a periphery of the medial posterior portion. The first gripping portion is strip-shaped and has a dimension larger than that of the spacer in the longitudinal direction of the first member,
The spacer insertion tool according to claim 1 , wherein a tip of the first gripping portion is disposed at a position protruding beyond a tip of the spacer in the longitudinal direction. The spacer insertion instrument according to claim 1, further comprising an opening mechanism for opening the gap by inserting the second gripping portion from the tip of the second gripping portion along the longitudinal direction of the second member into the gap between the first and second bone resection surfaces. The spacer insertion device according to claim 6, wherein the expansion mechanism has two faces that gradually approach each other in the width direction of the second gripping portion from the base end side to the tip end side. The spacer insertion device according to any one of claims 1 to 3, further comprising a connecting mechanism that connects the first gripping portion and the second gripping portion in a manner that allows them to move in the longitudinal direction of the first member or to be separated from each other. the connecting 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 relative 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 tool according to claim 8 , wherein the second position is a position in which a tip of the second gripping portion is disposed at or near a base end of the first gripping portion to release the spacer. The spacer insertion device according to claim 7, further comprising a guide mechanism that regulates the movement direction of the second gripping part relative to the first gripping part in the longitudinal direction. The first gripping portion has a flat tip,
The spacer insertion tool of claim 1 , wherein the first member includes a first handle portion extending parallel or substantially parallel to the tip portion. The spacer insertion device according to any one of claims 1 to 3, wherein the second support surface on the first gripping part side that supports the side surface of the second gripping part is inclined relative to the first gripping part in a direction approaching the first gripping part toward the tip. The spacer insertion tool according to any one of claims 1 to 3, wherein the first gripping portion has a non-slip surface in an area where the first gripping portion contacts the side surface of the spacer on the first support surface to prevent the spacer from slipping against the first support surface. The spacer insertion tool according to any one of claims 1 to 3, wherein the second gripping portion is capable of fitting into a groove formed on the side surface of the spacer.

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