JP7623838B2 - Bone surgery instruments - Google Patents

Description

The present invention relates to bone surgery instruments.

Conventionally, a bone surgery instrument has been used to guide a drill when drilling a pilot hole for an implant in a bone (see, for example, Patent Document 1). The bone surgery instrument in Patent Document 1 includes a tubular main body into which a drill is inserted, and a receiving part that faces the tip of the main body and receives the tip of the drill. By radially grasping the bone with the main body and receiving part and inserting the drill into the main body, a pilot hole can be made in the bone while applying radial pressure to the bone.

International Publication No. 2020/059405

In the case of distal tuberosity osteotomy (DTO), a type of osteotomy, tension in the patellar tendon applies a force to the tuberosity in a direction that causes it to float forward. Therefore, not only when creating a pilot hole in the bone, but also when inserting an implant into the pilot hole, it is necessary to apply pressure to the tibia in a direction that brings the tuberosity closer to the bone fragment behind the tuberosity.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a bone surgery instrument that can insert an implant into a bone while applying pressure to the bone.

According to one aspect of the present invention, there is provided a bone surgical instrument for inserting an implant having a shaft and a head having a larger diameter than the shaft into a bone, the bone surgical instrument comprising: a tubular guide member having a guide hole penetrating the guide member in the longitudinal direction thereof and into which the implant is inserted; a support portion supporting the guide member so that it is movable in the longitudinal direction; and a receiving portion disposed at a distance from a tip of the guide member in the longitudinal direction; and a washer member detachable from the tip of the guide member, the washer member having a contact surface disposed on the receiving portion side and brought into contact with the surface of the bone, a through hole which is disposed coaxially with the guide hole and has a diameter smaller than a diameter of the guide hole and through which the shank can pass, an engagement surface disposed around the through hole on the opposite side to the receiving portion and with which the head engages in the longitudinal direction, and a slot formed around the engagement surface and through which the tip of the guide member passes in the longitudinal direction, and a needle-shaped protrusion protruding toward the receiving portion side is provided at the tip of the guide member .

FIG. 1 is a side view showing an overall configuration of a bone surgical instrument according to one embodiment. FIG. 1 is a side view of an example of an implant for use in a bone surgical instrument. FIG. 13 is a perspective view of a guide member to which a washer member is attached. FIG. 4 is a top view of the washer member as viewed from the base end side. FIG. 4 is a partial vertical cross-sectional view of a guide member to which a washer member is attached. 5 is a longitudinal cross-sectional view of the washer member taken along line II of FIG. 4, showing a state in which the head of the implant is engaged with the engagement surface. 1A to 1C are diagrams illustrating an example of surgery using a bone surgery instrument. 13A and 13B are diagrams illustrating compression of two bone fragments by screwing in an implant. 13 is a perspective view of a modified example of a guide member having a protrusion at a tip thereof. FIG. 13 is a perspective view of a modified example of a washer member that can be screwed to the tip portion of the guide member. FIG. 13 is a longitudinal sectional view of a modified example of a washer member having a convex portion and a guide member having a concave portion. FIG. 13 is a longitudinal sectional view of a modified example of a washer member having a screw hole and a guide member having a recess. FIG. 13 is a perspective view of a modified example of a washer member having needle-like projections on a contact surface. FIG. FIG. 13 is a perspective view of a modified example of a washer member having a thread groove on an engagement surface. FIG. 15 shows the washer member of FIG. 14 attached to the head of the implant. FIG. 13 is a perspective view of a modified example of a washer member having two through holes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A bone surgical instrument and a bone surgical system according to an embodiment of the present invention will be described below with reference to the drawings.
The bone surgical system includes a bone surgical instrument 1 shown in Fig. 1 and an implant 2 shown in Fig. 2. The bone surgical instrument 1 may be provided separately from the implant 2, or may be provided together with the implant 2 as a bone surgical system.

The bone surgical instrument 1 is used in surgery to insert an implant 2 into a pilot hole drilled in bone A, and is a guide device that guides the drill that drills the pilot hole in bone A and the implant 2. As shown in FIG. 1, the bone surgical instrument 1 includes a cylindrical guide member 3 that guides the drill and implant 2, a main body 4 that supports the guide member 3, and a washer member 5 that is detachable from the tip of the guide member 3.

As shown in Fig. 2, the implant 2 is a fixture, such as a screw, that is fixed to a bone A. The implant 2 has a long shaft portion 2a and a head portion 2b that is located at the base end of the shaft portion 2a and has a larger diameter than the shaft portion 2a, and the shaft portion 2a is provided with a screw thread. A surface 2c of the head portion 2b on the shaft portion 2a side is an annular flange surface that has an outer diameter larger than the outer diameter of the shaft portion 2a. The flange surface 2c may be a tapered surface as shown in Fig. 2, or may be a flat surface.
The outer diameter of the shaft portion 2a is preferably 3 mm to 7 mm, and the outer diameter of the head portion 2b is preferably 4 mm to 10 mm. If the outer diameter of the implant 2 is too small, the strength of the implant 2 may be insufficient. If the outer diameter of the implant 2 is too large, the insertion position of the implant 2 may be limited, or the impact on the soft tissue surrounding the implant 2 may be increased.

As shown in Figs. 1 and 3, the guide member 3 is a cylindrical member that extends linearly, and has a guide hole 3a that passes through the guide member 3 in the longitudinal direction and into which the drill and the implant 2 are inserted.
At least one slit 3b is provided in the distal end of the guide member 3, extending in the longitudinal direction of the guide member 3 from the distal end toward the proximal end of the guide member 3. The slit 3b penetrates the guide member 3 from the outer peripheral surface to the inner peripheral surface, and the drill and the implant 2 in the guide hole 3a can be observed from the outside of the guide member 3 via the slit 3b. In the example of Fig. 3, four slits 3b are provided at four positions spaced apart in the circumferential direction, and the distal end of the guide member 3 is divided into four portions 3c.

The main body 4 comprises a support portion 6 that supports the guide member 3, a receiving portion 7 that receives the tip of the drill protruding from the tip of the guide member 3, and a hook-shaped support 8 that connects the support portion 6 and the receiving portion 7 to each other.
The pillar 8 is curved in a substantially U-shape or a substantially C-shape, and is disposed radially outward of the bone A so as to surround substantially half the circumference of the bone A. The support portion 6 is fixed to one end of the pillar 8, and the receiving portion 7 is fixed to the other end of the pillar 8.

The support part 6 is a cylindrical member, and has a through hole 6a that penetrates the support part 6 in the longitudinal direction and into which the guide member 3 is inserted. The support part 6 supports the guide member 3 in the through hole 6a so that it can move in the longitudinal direction. By moving the guide member 3, the distance between the tip of the guide member 3 and the receiving surface 7a is adjusted according to the thickness of the bone A. In addition, the support part 6 can fix and release the guide member 3 to the support part 6 in the longitudinal direction.

For example, the support portion 6 has a locking mechanism that fixes and unlocks the guide member 3 in the longitudinal direction.
One example of the locking mechanism is a click mechanism having a protrusion that protrudes from and retracts from the inner surface of the through hole 6a. A plurality of grooves arranged in the longitudinal direction of the guide member 3 are formed on the outer peripheral surface of the guide member 3. The protrusions are biased radially inward by a spring or the like. With the protrusions fitted into the grooves, the guide member 3 is fixed in the longitudinal direction relative to the support portion 6. When a longitudinal force of a certain magnitude or greater is applied to the guide member 3, the protrusions retract, releasing the fixation of the guide member 3.
Another example of the locking mechanism is a fixing screw provided in the support part 6. A threaded hole penetrating from the outer circumferential surface to the inner circumferential surface of the support part 6 is formed in the support part 6. By tightening the fixing screw inserted into the threaded hole, the guide member 3 is fixed in the longitudinal direction relative to the support part 6, and by loosening the fixing screw, the fixation of the guide member 3 is released.

The receiving portion 7 is a plate-shaped member that is perpendicular to the extension line of the central axis of the guide hole 3a. The receiving portion 7 is disposed at a position spaced apart from the tip of the guide member 3 in the longitudinal direction of the guide member 3, and faces the tip of the guide member 3 in the longitudinal direction. The receiving portion 7 receives the tip of the drill on the receiving surface 7a on the guide member 3 side. The receiving surface 7a may be a flat surface or a curved surface that follows the surface shape of the bone A.

3 and 4, the washer member 5 is a substantially disk-shaped member having an outer diameter larger than the outer diameter of the tip of the guide member 3. The thickness of the washer member 5 is preferably 0.5 mm to 3 mm, and the width (outer diameter) of the washer member 5 is preferably 7 mm to 16 mm.
The washer member 5 has two concentric or nearly concentric annular walls 5a, 5b, a slot 5c formed between the walls 5a, 5b, and a through hole 5d formed radially inward of the inner wall 5b.

The outer wall 5a has an inner diameter approximately equal to the outer diameter of the tip portion of the guide member 3, and is disposed radially outward of the outer circumferential surface of the tip portion of the guide member 3. The inner wall 5b has an outer diameter approximately equal to the inner diameter of the tip portion of the guide member 3, and is disposed radially inward of the inner circumferential surface of the tip portion of the guide member 3. The two walls 5a, 5b are connected to each other by at least one support 5e extending radially between the walls 5a, 5b.
The slot 5c is an arc-shaped space formed between the inner peripheral surface of the outer wall 5a and the outer peripheral surface of the inner wall 5b, penetrating the washer member 5 in the thickness direction. Both ends of the slot 5c terminate at the support posts 5e. The tip end of the guide member 3 can penetrate the slot 5c in the thickness direction while passing through the support posts 5e in the slit 3b. That is, the slot 5c functions as a fitting portion that receives the tip end of the guide member 3.

The washer member 5 is attached to the tip of the guide member 3 by fitting the tip of the guide member 3 into and passing through the slot 5c. That is, the washer member 5 is self-held at the tip of the guide member 3 by friction between the inner surface of the slot 5c and the outer and inner peripheral surfaces of the tip of the guide member 3. The washer member 5 can be removed from the tip of the guide member 3 by pressing or pulling the washer member 5 toward the receiving portion 7.
3 and 4, the portion 3c of the guide member 3 penetrates each of the four slots 5c. When the washer member 5 is attached to the tip end of the guide member 3, the tip end of the guide member 3 protrudes from a surface 5f (tip end surface) of the washer member 5 on the receiving portion 7 side.

Fig. 5 is a longitudinal cross-sectional view along the longitudinal axis of the guide member 3 with the washer member 5 attached to the tip portion. As shown in Fig. 5, the outer peripheral surface of the tip portion of the guide member 3 may be tapered toward the tip. With this configuration, the tip portion of the guide member 3 can be easily pushed into the slot 5c, and the washer member 5 can be easily attached to the tip portion of the guide member 3. In addition, the washer member 5 can be easily removed from the guide member 3.
Instead of the outer peripheral surface of the tip end of the guide member 3, the inner surface on the radially outer side of the slot 5c may be tapered.

The through hole 5d penetrates the washer member 5 in the thickness direction, and is arranged coaxially or approximately coaxially with the guide hole 3a when the washer member 5 is attached to the tip of the guide member 3. The diameter of the through hole 5d is larger than the outer diameter of the drill and the shank 2a, and smaller than the diameter of the guide hole 3a and the outer diameter of the flange surface 2c. Therefore, the drill and the shank 2a can pass through the through hole 5d, but the head 2b cannot pass through the through hole 5d.

Furthermore, the washer member 5 has a contact surface 5f on the receiving portion 7 side (tip side), and an engagement surface 5g on the opposite side to the receiving portion 7 (base end side).
The contact surface 5f is a surface that is brought into contact with the surface of the bone A. Specifically, the contact surface 5f is made up of the walls 5a, 5b and the tip surface of the support 5e, and has an area larger than the tip surface of the guide member 3 and the flange surface 2c. The contact surface 5f may be a flat surface or a curved surface that follows the convex shape of the surface of the bone A.

The engagement surface 5g is an annular base end surface of the inner wall 5b, and is arranged around the through hole 5d. FIG. 6 is a cross-sectional view of the washer member 5 in FIG. 4 taken along line I-I. As shown in FIG. 6, the flange surface 2c abuts against the engagement surface 5g, causing the head 2b to engage with the engagement surface 5g in the longitudinal direction of the guide member 3. The engagement surface 5g may have a shape corresponding to the shape of the flange surface 2c. For example, if the flange surface 2c is tapered, the engagement surface 5g may be a tapered surface that is recessed into the receiving portion 7 to receive the head 2b.

Next, the operation of the bone surgical instrument 1 and the bone surgical system will be described.
7 shows DTO (Distal-tuberosity osteotomy) as an example of use of the bone surgery instrument 1. DTO is a method of performing bone cutting distal to the tuberosity B in high tibial osteotomy (HTO) in order to connect the tuberosity B to a proximal bone fragment C of the tibia A.
The bone surgery instrument 1 can also be used to make pilot holes in bones other than the tibia and to insert the implants 2.

As shown in FIG. 7, the tibia A is sandwiched in the front-rear direction at the position of the rough surface B by the guide member 3 to which the washer member 5 is attached and the receiving part 7, and the guide member 3 is moved in a direction approaching the receiving part 7 until the tip surface of the guide member 3 protruding from the contact surface 5f and the receiving surface 7a come into contact with the surface of the tibia A, and the guide member 3 is fixed to the support part 6. As a result, the guide member 3 and the receiving part 7 hold the tibia A in the radial direction, and pressure is applied to the tibia A in a direction that brings the anterior bone fragment A1 and the posterior bone fragment A2 including the rough surface B closer to each other. The guide member 3 is disposed on the anterior side of the tibia A, and the receiving part 7 is disposed on the posterior side of the tibia A.

Next, a drill is inserted into the guide hole 3a of the guide member 3, and a pilot hole is created in the tibia A by the rotating drill. During the creation of the pilot hole, the drill is guided straight along the central axis of the guide hole 3a, so that a pilot hole extending straight along the extension of the central axis of the guide hole 3a can be created.

When the drill penetrates the tibia A, the tip of the drill strikes the receiving surface 7a on the surface of the tibia A and is received by the receiving part 7. This prevents the tip of the drill from being exposed to the tissues surrounding the tibia A, and protects the tissues surrounding the tibia A from the tip of the drill. In the case of DTO, the tip of the drill that penetrates the tibia A from the front to the rear is prevented from being exposed to the nerves, blood vessels, etc. present behind the tibia A.

After the drill is removed from the pilot hole and the guide hole 3a, the implant 2 is inserted into the guide hole 3a, and the implant 2 is screwed into the pilot hole by rotating a driver (not shown) connected to the head 2b.
After the implant 2 is screwed into the pilot hole until the head 2b abuts against the engagement surface 5g of the washer member 5, the implant 2 is further screwed into the pilot hole with the head 2b engaged with the engagement surface 5g. The washer member 5 is pressed toward the tibia A by the head 2b, and moves toward the tibia A relative to the guide member 3, and the contact surface 5f comes into contact with the surface of the tibia A. At this time, the movement of the washer member 5 causes the washer member 5 to be released from the tip of the guide member 3.

After the contact surface 5f comes into contact with the surface of the tibia A, when the implant 2 is further screwed into the pilot hole, the rear bone fragment A2 is pulled forward as shown in Figure 8, and further pressure is applied to the tibia A in a direction that brings the bone fragments A1 and A2 closer to each other.
When the implant 2 is screwed in with the head 2b engaged with the engagement surface 5g, a rotational force is transmitted from the implant 2 to the washer member 5. However, the support post 5e abuts against the guide member 3 in the slot 5c, thereby preventing the washer member 5 from rotating relative to the tibia A.
After the implant 2 has been screwed into the tibia A until sufficient compression is applied to the tibia A, the guide member 3 and the body 4 are removed from the tibia A, leaving the implant 2 and the washer member 5 in place on the tibia A.

Thus, according to this embodiment, the pilot hole is prepared and the implant 2 is screwed into the pilot hole while pressure is applied to the tibia A by the guide member 3. The tension of the patellar tendon connected to the rough surface B applies a force to the rough surface B to float it forward. By applying pressure to the tibia A at the position of the rough surface B, it is possible to prevent the bone fragment A1 including the rough surface B from floating, and the two bone fragments A1 and A2 can be fixed by the implant 2 with the bone fragment A1 in appropriate contact with the bone fragment A2.

In addition, since the area of the tip surface of the guide member 3 is small, the tip of the guide member 3 easily bites into the surface of the bone A. On the other hand, the contact surface 5f contacts the surface of the bone A over a larger contact area than the tip surface of the guide member 3, so that even if the surface of the bone A is soft, the washer member 5 is prevented from biting into the bone A. Therefore, the washer member 5 attached to the tip of the guide member 3 can prevent the tip of the guide member 3 from biting into the bone A.
Furthermore, in a state in which the washer member 5 is in contact with the surface of the tibia A, pressure is also applied to the tibia A from the washer member 5 by screwing the implant 2. In other words, the implant 2 can be screwed into the pilot hole while applying a greater pressure to the tibia A.

Furthermore, if the implant 2 is further screwed into the pilot hole without the washer member 5 and with the head 2b in direct contact with the surface of the bone A, the head 2b may sink into the surface of the bone fragment A1 as the implant 2 is screwed in, making it impossible to apply pressure to the bone fragments A1 and A2. In particular, if the surface of the bone fragment A1 is soft, the head 2b is likely to sink into the surface of the bone fragment A1, making it difficult to apply pressure by screwing the implant 2 in.
According to this embodiment, the contact surface 5f contacts the surface of the bone A over a larger contact area than the flange surface 2c, preventing the washer member 5 from being embedded in the surface of the bone fragment A1. This allows the implant 2 to be screwed in to apply pressure more effectively to the bone fragments A1 and A2.

In the above embodiment, a protrusion 3d may be provided at the tip of the guide member 3 as shown in FIG.
The protrusion 3d is needle-shaped with a sharp tip and protrudes toward the receiving portion 7. The guide member 3 can be fixed to the bone A by piercing the surface of the bone A with the protrusion 3d.

In the above embodiment, the washer member 5 has a slot 5c through which the guide member 3 passes as an engagement portion that receives the tip portion of the guide member 3, but an engagement portion other than the slot 5c may be provided on the washer member 5.
For example, the fitting portion may be a recess or hole defined by an annular or cylindrical outer wall 5a, the tip portion of the guide member 3 fitting into the outer wall 5a, and the washer member 5 may be fixed to the tip portion of the guide member 3 by friction between the inner surface of the outer wall 5a and the outer surface of the tip portion of the guide member 3.

In the above embodiment, the washer member 5 is fixed to the tip of the guide member 3 by friction, but instead, the washer member 5 may be fixed to the tip of the guide member 3 by other fixing means. Figures 10 to 12 show other examples of the fixing means.
10 to 12, the washer member 5 has an outer wall 5a and an annular tip wall 5h provided at the tip of the outer wall 5a. The through hole 5d is a hole surrounded by the inner circumferential surface of the tip wall 5h, the contact surface 5f is the tip surface of the tip wall 5h, and the engagement surface 5g is the base end surface of the tip wall 5h.

10, the washer member 5 is screwed to the tip end of the guide member 3. That is, a screw groove 5i is formed on the inner peripheral surface of the outer wall 5a of the washer member 5, and a screw thread (not shown) that fastens to the screw groove 5i is formed on the outer peripheral surface of the tip end of the guide member 3.
According to this configuration, after the implant 2 is inserted to an appropriate depth in the tibia A, the washer member 5 and the guide member 3 can be separated from each other by rotating the guide member 3 relative to the washer member 5.

11, at least one protrusion 9a protruding radially inward is provided on the inner peripheral surface of the outer wall 5a of the washer member 5, and at least one recess 9b for receiving the protrusion 9a is provided on the outer peripheral surface of the tip portion of the guide member 3. The recess 9b may penetrate from the outer peripheral surface to the inner peripheral surface of the guide member 3.
According to this configuration, after the implant 2 is placed in the tibia A, the engagement between the convex portion 9a and the concave portion 9b can be released by moving the guide member 3 toward the base end side relative to the washer member 5, and the washer member 5 and the guide member 3 can be separated from each other. The washer member 5 may be configured so that the engagement between the convex portion 9a and the concave portion 9b can be released by pressing the washer member 5 with the head portion 2b engaging with the engagement surface 5g.
The arrangement of the convex portion 9 a and the concave portion 9 b may be reversed. That is, at least one convex portion 9 a protruding radially outward may be provided on the outer circumferential surface of the tip portion of the guide member 3, and at least one concave portion 9 b for receiving the convex portion 9 a may be provided on the inner circumferential surface of the outer wall 5 a of the washer member 5.

12, a screw hole 10a is provided in the outer wall 5a of the washer member 5, through which a fixing screw (not shown) is fastened in the radial direction, and a recess 10b into which the fixing screw is inserted is provided in the outer peripheral surface of the tip of the guide member 3. The recess 10b may penetrate from the outer peripheral surface to the inner peripheral surface of the guide member 3.
According to this configuration, the washer member 5 is fixed to the tip portion of the guide member 3 by inserting the fixing screw into the recess 10b via the screw hole 10a. The washer member 5 and the guide member 3 can be separated from each other at any time by removing the fixing screw from the recess 10b.

In the above embodiment, as shown in FIG. 13, at least one needle-like projection 11 may be provided on the contact surface 5f.
The protrusion 11 protrudes from the contact surface 5f toward the receiving part 7 and has a sharp tip. The protrusion 11 penetrates the surface of the bone A, thereby fixing the washer member 5 to the surface of the bone A. In addition, the protrusion 11 penetrating the bone A can prevent the washer member 5 from floating off the surface of the bone A after the implant 2 is implanted.

In the above embodiment, a screw groove 12 may be formed on the engagement surface 5g as shown in Fig. 14. The washer member 5 having the screw groove 12 is used in combination with an implant 2 having a screw thread 2d provided on a head portion 2b as shown in Fig. 15. That is, the head portion 2b is fixed to the washer member 5 by fastening the screw thread 2d to the screw groove 12.
When the implant 2 is screwed into the prepared hole, the head 2b rotates relative to the engagement surface 5g while being in contact with the engagement surface 5g. According to the above-mentioned configuration, it is possible to prevent wear powder from being generated between the head 2b and the engagement surface 5g.

In the above embodiment, as shown in Fig. 16, the washer member 5 may have, in addition to the through hole 5d, another through hole 13 radially outward of the through hole 5d. The washer member 5 in Fig. 16 is substantially in the shape of a figure eight, in which a first annular portion 51 including the through hole 5d and a second annular portion 52 including the other through hole 13 are interconnected.
According to this configuration, the bone pieces A1, A2 can be more firmly fixed to each other by inserting the two implants 2 into the bone A via the two through holes 5d, 13. In Fig. 16, a screw groove 12 is formed on the engagement surface 5g of the through hole 5d. In order to fix the head 2b of the implant 2 in the through hole 13 to the washer member 5, the screw groove 12 may also be formed on the inner surface of the through hole 13.
The washer member 5 may have three or more through holes. When the washer member 5 has multiple through holes, the length of the washer member 5 is preferably 25 mm or less to reduce the influence on soft tissue. The length is the dimension in the arrangement direction of the multiple through holes.

The central axes (see dashed lines) of the two through holes 5d, 13 may be parallel to each other or may be inclined to each other.
When the central axes are inclined relative to each other, the two implants 2 can be made difficult to come out of the bone A. That is, the longitudinal axes of the two implants 2 inserted into the bone A via the two through holes 5d, 13 are inclined relative to each other. Therefore, for example, when a longitudinal force in a direction to come out of the bone A is applied to one of the implants 2, the one implant 2 is prevented from coming out of the bone A by the other implant 2. In addition, the two implants 2 whose longitudinal axes are inclined relative to each other can structurally prevent the bone pieces A1, A2 from moving away from each other.

It is preferable that the angle between the longitudinal axes of the two implants 2, i.e., the angle X between the central axes of the two through holes 5d, 13, satisfies -45°<X<45°. If the angle X is 45° or more, the force in the direction of misalignment of the bone pieces A1, A2 when the second implant 2 is inserted into the bone A will be large, which is not preferable.

The washer member 5 having two through holes 5d, 13 is larger than a washer member 5 having only one through hole 5d, and therefore may have a greater effect on the soft tissue surrounding the bone A. Therefore, in order to reduce the effect on the soft tissue, it is preferable that the width of the portion of the washer member 5 that is not connected to the guide member 3 is narrow. Specifically, it is preferable that the width of the second portion 52 is smaller than the width of the first portion 51. The width is the dimension in the direction perpendicular to the arrangement direction of the through holes 5d, 13.

The connecting portion 53 between the first portion 51 and the second portion 52 may be a low-rigidity portion having a lower rigidity than the first portion 51 and the second portion 52. For example, the connecting portion 53 may be a constricted portion having a width narrower than the width of the second portion 52, and may be thinner than the first portion 51 and the second portion 52. With this configuration, the washer member 5 can be easily bent at the connecting portion 53, which is a low-rigidity portion, so that the washer member 5 fits the convex shape of the surface of the bone A.

In addition, taking into consideration the deformation and strength of the washer member 5, it is preferable that the width of the low rigidity portion 53 is 50% to 90% of the width of the second portion 52, and the thickness of the low rigidity portion 53 is 60% to 90% of the thickness of the first portion 51 and the second portion 52. If the difference in width and thickness between the low rigidity portion 53 and the portions 51 and 52 is too small, the washer member 5 may bend at an unintended position other than the low rigidity portion 53. If the difference is too large, excessive stress is concentrated in the low rigidity portion 53, making the low rigidity portion 53 more susceptible to breakage.

In the above embodiment, the washer member 5 is in the shape of a circular plate, but the shape of the washer member 5 is not limited to this and can be changed as appropriate.
In the above embodiment, the implant 2 is a fixture, but the implant 2 may be for other purposes and have a stem and a head.

REFERENCE SIGNS LIST 1 Bone surgery instrument 2 Implant 2a Shank 2b Head 3 Guide member 3a Guide hole 4 Body 5 Washer member 51 First portion 52 Second portion 53 Connection portion, low rigidity portion 5a Outer wall 5c Slot, fitting portion 5d, 13 Through hole 5f Contact surface 5g Engagement surface 6 Support portion 7 Receiving portion 9a Convex portion 9b Concave portion 10a Screw hole 10b Concave portion 11 Protrusion 12 Thread groove

Claims (10)

A bone surgery instrument for inserting an implant having a shaft portion and a head portion having a diameter larger than that of the shaft portion into a bone,
A cylindrical guide member having a guide hole penetrating the guide member in a longitudinal direction thereof and into which the implant is inserted;
a main body having a support portion that supports the guide member movably in the longitudinal direction and a receiving portion that is disposed at a distance from a tip of the guide member in the longitudinal direction;
a washer member that is detachable from a tip end of the guide member,
The washer member is
a contact surface disposed on the receiving portion side and brought into contact with a surface of the bone;
a through hole that is arranged coaxially with the guide hole, has a diameter smaller than a diameter of the guide hole, and through which the shaft portion can pass;
an engagement surface disposed around the through hole on the opposite side to the receiving portion and engaging with the head in the longitudinal direction ;
a slot formed around the engagement surface and through which the tip of the guide member passes in the longitudinal direction;
A bone surgery instrument , wherein the guide member has a needle-shaped protrusion at a tip thereof that protrudes toward the receiving portion . 2. The bone surgical instrument according to claim 1 , wherein the washer member has a fitting portion that receives the tip portion of the guide member and is fixed to the tip portion of the guide member by friction between the tip portion of the guide member and the fitting portion. A bone surgery instrument for inserting an implant having a shaft portion and a head portion having a diameter larger than that of the shaft portion into a bone,
A cylindrical guide member having a guide hole penetrating the guide member in a longitudinal direction thereof and into which the implant is inserted;
a main body having a support portion that supports the guide member movably in the longitudinal direction and a receiving portion that is disposed at a distance from a tip of the guide member in the longitudinal direction;
a washer member that is detachable from a tip end of the guide member,
The washer member is
a contact surface disposed on the receiving portion side and brought into contact with a surface of the bone;
a through hole that is arranged coaxially with the guide hole, has a diameter smaller than a diameter of the guide hole, and through which the shaft portion can pass;
an engagement surface disposed around the through hole on the opposite side to the receiving portion and engaging with the head in the longitudinal direction;
a fitting portion for receiving a tip end of the guide member,
A bone surgery instrument, wherein the washer member is fixed to the distal end of the guide member by friction between surfaces along the longitudinal direction between the distal end of the guide member and the fitting portion. A bone surgery instrument for inserting an implant having a shaft portion and a head portion having a diameter larger than that of the shaft portion into a bone,
A cylindrical guide member having a guide hole penetrating the guide member in a longitudinal direction thereof and into which the implant is inserted;
a main body having a support portion that supports the guide member movably in the longitudinal direction and a receiving portion that is disposed at a distance from a tip of the guide member in the longitudinal direction;
a washer member that is detachable from a tip end of the guide member,
The washer member is
a contact surface disposed on the receiving portion side and brought into contact with a surface of the bone;
a through hole that is arranged coaxially with the guide hole, has a diameter smaller than a diameter of the guide hole, and through which the shaft portion can pass;
an engagement surface disposed around the through hole on the opposite side to the receiving portion and engaging with the head in the longitudinal direction;
an annular outer wall disposed outside an outer circumferential surface of the tip portion of the guide member,
a protrusion is provided on one of an inner surface of the outer wall and an outer circumferential surface of the tip portion of the guide member,
A bone surgery instrument, wherein a recess for receiving the protrusion is provided on the other of the inner surface of the outer wall and the outer circumferential surface of the tip portion of the guide member. A bone surgery instrument for inserting an implant having a shaft portion and a head portion having a diameter larger than that of the shaft portion into a bone,
A cylindrical guide member having a guide hole penetrating the guide member in a longitudinal direction thereof and into which the implant is inserted;
a main body having a support portion that supports the guide member movably in the longitudinal direction and a receiving portion that is disposed at a distance from a tip of the guide member in the longitudinal direction;
a washer member that is detachable from a tip end of the guide member,
The washer member is
a contact surface disposed on the receiving portion side and brought into contact with a surface of the bone;
a through hole that is arranged coaxially with the guide hole, has a diameter smaller than a diameter of the guide hole, and through which the shaft portion can pass;
an engagement surface disposed around the through hole on the opposite side to the receiving portion and engaging with the head in the longitudinal direction;
a ring-shaped outer wall disposed outside an outer circumferential surface of the tip portion of the guide member; and a screw hole formed in the outer wall and penetrating the outer wall in a thickness direction,
A bone surgery instrument, wherein the outer peripheral surface of the tip portion of the guide member is provided with a recess for receiving a screw passing through the screw hole. 6. The bone surgery instrument according to claim 1 , wherein the contact surface is provided with needle-like projections protruding from the contact surface. 7. The bone surgical instrument according to claim 1, wherein said engagement surface is threaded. 8. The bone surgical instrument according to claim 1, wherein the washer member has another through hole radially outward from the through hole. the washer member has a first portion including the through hole and a second portion including the other through hole,
The bone surgical instrument of claim 8 , wherein the second portion has a width less than a width of the first portion. 10. The bone surgical instrument according to claim 8 , wherein the washer member has a low rigidity portion between the through hole and the other through hole, the low rigidity portion having a rigidity lower than that of other portions of the washer member.