Artificial knee joint replacement operation instrument

When using an artificial knee joint replacement operation instrument, the amount of labor required to attach a tibial insert trial to a patient is further reduced. An artificial knee joint replacement operation instrument has a tibial trial attachment instrument assembly used in an operation for replacing a patient's knee joint with an artificial knee joint. The tibial trial attachment instrument assembly includes a template to be attached to a tibia, a keel punch guide to be joined to the tibia via the template, a keel punch to be inserted into the tibia through the keel punch guide, a keel punch handle for operating the keel punch, and a tibial insert trial to be placed on the template, the tibial insert trial being separate from the template.

TECHNICAL FIELD

The present invention relates to an artificial knee joint replacement operation instrument used in an operation for replacing a patient's knee joint with an artificial knee joint.

BACKGROUND ART

In an artificial knee joint replacement operation for replacing a patient's knee joint with an artificial knee joint, an operator performs osteotomy on a distal portion of a femur using a surgical instrument, and disposes a femoral component onto a cut bone surface formed as a result of the osteotomy. The operator also performs osteotomy on a proximal portion of a tibia using a surgical instrument, and disposes a tibial component onto a cut bone surface formed as a result of the osteotomy. When the tibial component is attached, a tibial trial is tentatively attached to the cut bone surface of the tibia. An optimal tibial component for the patient is determined by referencing this tibial trial (e.g. see Patent Documents 1 and 2).

In the configuration described in Patent Document 1, a base portion trial (12) attached to an alignment handle (16) is aligned with a proximal end (20) of a tibia (22). Next, a guide tower (14) is driven into the tibia (22). Then, a keel punch (220), to which an impaction handle (222) has been attached, is inserted into the guide tower (14), and the keel punch (220) is driven into the tibia (22). Here, the impaction handle (222) and the keel punch (220) are locked to each other due to a leading end of a lever (308) of the impaction handle (222) being caught on a lever-receiving notch (246), which is formed at an upper end of the keel punch (220).

Upon the impaction handle (222) and the keel punch (220) being inserted by a predetermined amount or more into the guide tower (14), the lever (308) is pressed by the guide tower (14). As a result, the lever (308) and the lever-receiving notch (246) of the keel punch (220) are unlocked from each other. At the same time, the lever (308) is caught on the guide tower (14). That is to say, the impaction handle (222) and the guide tower (14) are locked with each other. If the impaction handle (222) is pulled in this state, the guide tower (14) is pulled out of the tibia (22) together with the impaction handle (222). Meanwhile, the keel punch (220) is left in the tibia (20).

In the configuration described in Patent Document 2, a tibial bearing component (32A) is attached to a base plate (38A), which corresponds to the base portion trial (12). According to the above configuration, an optimal tibial component for a patient is determined.

CITATION LIST

Patent Document

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

In the above configuration, instruments (the guide tower (14) and the impaction handle (222)) for fixing the keel punch (220) to the tibia (20), and the tibial bearing component (32A) need to be prepared separately, and preparation of these instruments is laborious.

The invention of this application aims to further reduce the amount of labor required to attach a tibial insert trial to a patient, when using an artificial knee joint replacement operation instrument.

Means for Solving the Problem

(1) An artificial knee joint replacement operation instrument according to an aspect of the present invention to achieve the above-stated object includes: a tibial trial attachment instrument assembly to be used in an operation for replacing a patient's knee joint with an artificial knee joint, the tibial trial attachment instrument assembly including: a template to be attached to the patient's tibia; a keel punch guide to be joined to the tibia via the template; a keel punch to be inserted into the tibia through the keel punch guide; a keel punch handle for operating the keel punch; and a tibial insert trial to be placed on the template, the tibial insert trial being separate from the template.

According to this configuration, the template, the keel punch guide, the keel punch, the keel punch handle, and the tibial insert trial are prepared as a single assembly. Accordingly, these instruments can be prepared collectively, which is less laborious than in the case of preparing these instruments separately. Accordingly, the amount of labor required to attach the tibial insert trial to a patient can be further reduced.

(2) There are cases where the artificial knee joint replacement operation instrument further includes a first connection mechanism configured to enable the keel punch handle and the keel punch to be attached to and detached from each other, and prevent the keel punch handle from coming out from the keel punch.

According to this configuration, the first connection mechanism can prevent the keel punch handle from coming out from the keel punch. Also, the keel punch handle can be disconnected from the keel punch when necessary. This makes it possible to suppress the case where the keel punch handle and the keel punch become hindrances. As a result, the amount of labor required to attach the tibial insert trial to a patient can be further reduced.

(3) There are cases where the first connection mechanism is configured to connect and disconnect the keel punch handle to and from the keel punch by moving the keel punch handle relative to the keel punch in a predetermined first direction that differs from an axial direction of the keel punch handle.

According to this configuration, connection and disconnection between the keel punch handle and the keel punch can be performed with a simple configuration in which the keel punch handle and the keel punch are relatively moved in the first direction. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial to a patient.

(4) There are cases where the first direction is a rotational direction around an axis parallel to the axial direction.

According to this configuration, connection and disconnection between the keel punch handle and the keel punch can be performed with a simple configuration in which the keel punch handle and the keel punch are relatively rotated. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial to a patient.

(5) There are cases where the first connection mechanism has a first protrusion formed in one of the keel punch handle and the keel punch, and a first connected portion formed in the other one of the keel punch handle and the keel punch, and the first protrusion is connected to and disconnected from the first connected portion by relative movement of the keel punch handle and the keel punch.

According to this configuration, connection and disconnection between the first protrusion and the first connected portion can be performed with a simple operation, that is, relative movement of the keel punch handle and the keel punch.

(6) There are cases where the first protrusion is provided at a leading end of the keel punch handle, and is formed to have a rectangular shape in a cross-section orthogonal to an axial direction of the keel punch handle, and the first connected portion includes a first projection formed on an inner-circumferential face of a tubular portion provided in the keel punch.

According to this configuration, the keel punch handle can be connected to the keel punch by causing the first protrusion, which has a protruding shape, to be caught on the first protrusion formed in a hole in the keel punch. Also, the aforementioned connection can be canceled by rotating the first protrusion relative to the first projection.

(7) There are cases where a pair of the first projections is provided at a pitch of 180 degrees on the inner-circumferential face of the tubular portion, and a hole portion having a cross-sectional shape that matches a cross-sectional shape of the first protrusion is formed within the tubular portion.

According to this configuration, since the first protrusion can be received by the pair of first projections, the connection strength between the keel punch handle and the keel punch can be further increased. With this configuration, the operator does not need to pay attention to the connection strength between the keel punch handle and the keel punch when handling the keel punch handle to which the keel punch has been attached. As a result, the amount of labor required to attach the tibial insert trial to a patient can be further reduced.

(8) There are cases where the artificial knee joint replacement operation instrument further includes a second connection mechanism for enabling the keel punch handle and the keel punch guide to be attached to and detached from each other, and integrally connecting the keel punch handle to the keel punch guide.

According to this configuration, the second connection mechanism enables the keel punch handle and the keel punch guide to be integrally connected. This makes it possible to pull out the keel punch guide using the keel punch handle. Also, the keel punch handle can be disconnected from the keel punch guide when necessary. This makes it possible to suppress the case where the keel punch handle and the keel punch guide become hindrances. As a result, the amount of labor required to attach the tibial insert trial to a patient can be further reduced.

(9) There are cases where the second connection mechanism is configured to connect and disconnect the keel punch handle to and from the keel punch guide by moving the keel punch handle relative to the keel punch guide in a predetermined second direction that differs from an axial direction of the keel punch handle.

According to this configuration, connection and disconnection between the keel punch handle and the keel punch guide can be performed with a simple configuration in which the keel punch handle and the keel punch guide are relatively moved in the second direction. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial to a patient.

(10) There are cases where the second direction is a rotational direction around an axis parallel to the axial direction.

According to this configuration, connection and disconnection between the keel punch handle and the keel punch guide can be performed with a simple configuration in which the keel punch handle and the keel punch guide are relatively rotated. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial to a patient.

(11) There are cases where the second connection mechanism includes a second protrusion formed in one of the keel punch handle and the keel punch guide, and a second connected portion formed in the other one of the keel punch handle and the keel punch guide, and the second protrusion is connected to and disconnected from the second connected portion by relative movement of the keel punch handle and the keel punch guide.

According to this configuration, a simple operation, that is, relative movement of the keel punch handle and the keel punch guide enables connection and disconnection between the second protrusion and the second connected portion.

(12) There are cases where the artificial knee joint replacement operation instrument further includes: a first connection mechanism configured to enable the keel punch handle and the keel punch to be attached to and detached from each other, and prevent the keel punch handle from coming out from the keel punch; and a second connection mechanism for enabling the keel punch handle and the keel punch guide to be attached to and detached from each other, and integrally connecting the keel punch handle to the keel punch guide, wherein connection between the keel punch handle and the keel punch through the first connection mechanism is canceled, and also the keel punch handle is connected-to the keel punch guide through the second connection mechanism.

According to this configuration, a single motion to displace the keel punch handle in one direction relative to the keel punch and the keel punch guide makes it possible to simultaneously cancel the connection between the keel punch handle and the keel punch through the first connection mechanism and connect the keel punch handle to the keel punch guide through the second connection mechanism. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial to a patient, through a reduction in the amount of labor in handling the keel punch handle.

(13) There are cases where a direction in which the keel punch handle is displaced relative to the keel punch to connect the keel punch handle to the keel punch through the first connection mechanism and a direction in which the keel punch handle is displaced relative to the keel punch guide to connect the keel punch handle to the keel punch guide through the second connection mechanism are set to opposite directions.

According to this configuration, a configuration can be realized that makes it possible to simultaneously perform an operation to cancel the connection between the keel punch handle and the keel punch through the first connection mechanism and an operation to connect the keel punch handle to the keel punch guide through the second connection mechanism. It is thus possible to further reduce the amount of labor required to attach the tibial insert trial to a patient, through a reduction in the amount of labor in handling the keel punch handle.

(14) There are cases where the keel punch guide includes a tubular portion that is provided to allow the keel punch to pass therethrough and is arranged in alignment with the template, and a passage through which a template handle for operating the template passes when the template handle is removed from the template is formed in an outer-circumferential portion of the tubular portion.

According to this configuration, even in a state in which the space around the tibia is small because, for example, the template has been attached to a patient's tibia, the template handle can be removed from the template through the passage. This makes it possible to more easily operate the template handle. Accordingly, the amount of labor required to attach the tibial insert trial to a patient can be further reduced.

(15) There are cases where the tibial trial attachment instrument assembly includes a spacer capable of being inserted between the tibial insert trial and the template.

According to this configuration, the spacer for adjusting the height of the tibial insert trial from the template is included in the tibial trial attachment instrument assembly. This eliminates the need for a laborious operation to prepare the spacer separately from other members of the tibial trial attachment instrument assembly. Accordingly, the amount of labor required to attach the tibial insert trial to a patient can be further reduced.

Effects of the Invention

According to the present invention, the labor required to attach the tibial insert trial to a patient can be further reduced.

DESCRIPTION OF EMBODIMENTS

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. Note that the present invention is broadly applicable as an artificial knee joint replacement operation instrument used in an operation for replacing a knee joint with an artificial knee joint.

FIG. 1is a perspective view showing an artificial knee joint replacement operation instrument1according to the present invention, and a portion of a patient's tibia100. Referring toFIG. 1, the artificial knee joint replacement operation instrument1is used in an artificial knee joint replacement operation for replacing a patient's knee joint with an artificial knee joint. This artificial knee joint replacement operation is used to restore normal functionality of a knee of a patient whose knee joint has deformed to a high degree due to gonarthrosis or chronic rheumatism, for example.

In the artificial knee joint replacement operation, osteotomy is performed on a proximal portion101of the patient's tibia100, and a flat cut bone surface102is thus formed. Next, a tibial component suitable for the patient's tibia100is selected using a tibial insert trial18. Also, in the artificial knee joint replacement operation, osteotomy is performed on a distal portion of the patient's femur (not shown), and thereafter, a femoral component suitable for the patient's femur is selected using a femoral trial. Then, the tibial component is attached to the proximal portion101of the tibia100, and the femoral component is attached to the distal portion of the femur. The tibial component and the femoral component slide as the patient's knee bends, thereby achieving smooth bending of the knee.

In the present embodiment, the terms “inner side” and “outer side” refer respectively to the inner side and the outer side of the patient's knee that is to be subjected to an artificial knee joint replacement operation. An inward-outward direction X1corresponds to the left-right direction of the patient. The “front” and the “rear” refer respectively to the front and the rear of the patient. “Above” and “below” refer respectively to above and below for the patient (lengthwise direction of the tibia100). In this embodiment, each component of the artificial knee joint replacement operation instrument1is described based on a state of having been attached to the proximal portion101of the patient's tibia100.

The artificial knee joint replacement operation instrument1includes a tibial trial attachment instrument assembly2.

The tibial trial attachment instrument assembly2is an instrument assembly for attaching the tibial insert trial18to the tibia100. Component of the tibial trial attachment instrument assembly2are accommodated in a single case, or are shipped as a single set from a factory, and are handled as a single set in a medical institution, for example.

The tibia trial attachment instrument assembly2has a template handle11, a template12that is to be attached to the patient's tibia100, a keel punch guide13to be joined to the tibia100via the template12, a drill14, a drill stopper15, a keel punch16to be inserted into the tibia100through the keel punch guide13, a keel punch handle17for operating the keel punch16, and a tibial insert trial18that is separate from the template12and is to be placed on the template12, and a spacer19that can be inserted between the tibial insert trial18and the template12.

The above-listed components11to19of the tibial trial attachment instrument assembly2are made of a material such as metal or a synthetic resin. The above-listed components11to19are preferably made of a biocompatible material, and it is preferable that at least a portion that may come into contact with the patient is made of a biocompatible material.

Note that the tibial trial attachment instrument assembly2need only have any combination of at least two of the above-listed components11to19, and is not limited to the above configuration. For example, in the artificial knee joint replacement operation instrument1, at least one of the template handle11, the drill14, and the drill stopper15does not need to be included in the tibial trial attachment instrument assembly2.

FIG. 2is a perspective view of the template handle11, the template12, the keel punch guide13, and the tibia100. Referring toFIGS. 1 and 2, the template handle11is used to operate the template12. In a state in which an operator is holding the template handle11, the template12is removably attached to a leading end of the template handle11.

The template handle11includes a holding portion11a, which is to be held by the operator, a lock lever11band a lock pin11c, which are supported by the holding portion11a, and a connecting portion11d, which is formed at a leading end of the holding portion11a.

The holding portion11ais formed into an elongated bar shape, and is arranged in front of the proximal portion101of the tibia100, for example. The lock lever11bis supported by the holding portion11aat a front-end side portion thereof such that the lock lever11bcan slide relative to the holding portion11ain the lengthwise direction thereof. The lock pin11cprotrudes from the leading end of the holding portion11a. The lock pin11cis a shaft-shaped member, and is formed into a cylindrical shaft shape, for example. This lock pin11cis configured to be displaced integrally with the lock lever11b. The connecting portion11dis arranged in on one side of the lock pin11c. The connecting portion11dis provided as a portion that is mated with a later-described connected portion22of the template12. The connecting portion11dis formed so as to increase in width as it extends toward a leading end thereof, for example.

As mentioned above, the template12is attached to the template handle11. The template12is a plate-shaped member that is placed on the cut bone surface102of the proximal portion101of the tibia100, on which the keel punch guide13or the tibial insert trial18is selectively placed, and through which the keel punch16is passed. The template12has a shape that substantially matches the shape of the cut bone surface102when seen in a plan view. Also, the template12is formed into a symmetrical shape in the inward-outward direction X1.

FIG. 3is a perspective view of the template12.FIG. 4Ais a plan view of the template12.FIG. 4Bis a front elevational view of the template12. Referring toFIGS. 2, 3, 4A, and 4B, the template12has a central portion20, side portions21A and21B, a connected portion22and two pin hole portions23that are arranged in a front portion of the template12for connection with the template handle11, a first spacer receiving portion24for receiving the spacer19, a guide receiving portion25for receiving the keel punch guide13, a keel punch insertion hole portion26, stud insertion hole portions27ato27d, and fixing pin insertion hole portions30ato30f.

The central portion20is formed over a predetermined range including the central portion of the template12in the inward-outward direction X1. The central portion20is formed over approximately the entire range of the template12in a front-rear direction Y1. A front portion of the central portion20extends substantially straight in the inward-outward direction X1. A recessed portion that is recessed forward is formed in a rear portion of the central portion20. In the inward-outward direction X1, the length of the central portion20is set substantially the same as the length of the spacer19. Also, two side portions21A and21B are arranged respectively on the right side and the left side of the central portion20in the inward-outward direction X1.

The side portions21A and21B are portions each having an edge portion formed into a curved shape that is close to an arc, when viewed in a plan view. In this embodiment, in the inward-outward direction X1, the length of each of the side portions21A and21B is set shorter than the length of the central portion20. The connected portion22is provided at a front end of the central portion20.

The connected portion22is formed into a hole shape that matches the shape of the connecting portion11dat the leading end of the template handle11, and is open in an upper face of the template12. The pin hole portions23are formed respectively on the right side and the left side of the connected portion22. The lock pin11cof the template handle11is inserted into either one of the pin hole portions23. According to this configuration, the connecting portion11dof the template handle11is inserted into the connected portion22, and the lock pin11cis inserted into one of the pin hole portions23, and thus the template12is connected to the template handle11. Also, the template handle11can be removed from the template12by lifting up the template handle11from the template12, in a state in which the lock pin11chas been pulled out of the one of pin hole portions23.

The template12includes first to fourth upper faces28ato28d.

In the inward-outward direction X1, the first upper face28ais formed in front end portions of the side portions21A and21B of the template12, and also in the central portion20. The first upper face28ais a flat face, and includes a front portion28a1, a rear portion28a2, and a pair of side portions28a3that are arranged in the same plane.

The front portion28a1of the first upper face28ais provided in the central portion20as a face that is continuous with a front face of the central portion20, and the connected portion22is open in the front portion28a1. A rear end edge of the front portion28a1is formed into an arc shape to allow the keel punch16(seeFIG. 1) to pass through. A rear portion28a2of the first upper face28ais arranged rearward of the front portion28a1of the first upper face28a. The rear portion28a2of the first upper face28ais formed in the central portion20, and extends rearward. A front end edge of the rear portion28a2of the first upper face28ais formed into an arc shape to allow the keel punch16(seeFIG. 1) to pass through. The side portions28a3of the first upper face28aare provided in front end portions of the pair of side portions21A and21B, and are arranged next to the front portion28a1of the first upper face28ain the inward-outward direction X1. The size of the side portions28a3of the first upper face28ais set smaller than the size of the front portion28a1of the first upper face28a.

The stud insertion hole portions27ato27d, through which studs38ato38dof the keel punch guide13are to pass, are formed in the first upper face28aand the second upper face28b. The stud insertion hole portions27aand27bare arranged in the second upper face28b. The stud insertion hole portions27cand27dare arranged in the rear portion28a2of the first upper face28a, near the front end edge of the rear portion28a2.

The second upper face28bis also formed in the central portion20. The second upper face28bis arranged between the front portion28a1and the rear portion28a2of the first upper face28a. The height position of the second upper face28bis set lower than the position of the first upper face28a. The second upper face28bis formed into a symmetrical shape in the inward-outward direction X1. An inner end edge of the second upper face28bin the inward-outward direction X1is formed into an arc shape to allow the keel punch16(seeFIG. 1) to pass through.

The third upper face28cis formed on the outer side of the second upper face28bin the inward-outward direction X1. The third upper face28cis formed into a symmetrical shape in the inward-outward direction X1, and forms a portion of upper faces of the pair of side portions21A and21B. The height position of the third upper face28cis set lower than the position of the second upper face28b.

Side end walls29A and29B are formed in respective end portions of the third upper face28cin the inward-outward direction X1. The side end walls29A and29B are wall portions that are arranged close to a rear portion of the third upper face28c, and protrude upward. Each of the side end walls29A and29B has a step portion in an intermediate portion thereof, and the height position of rear portions of the side end walls29A and29B is set higher than the height position of front portions of the side end walls29A and29B.

The fourth upper face28dis arranged so as to be surrounded by the third upper face28cwhen seen in a plan view.

The fourth upper face28dis formed into a symmetrical shape in the inward-outward direction X1, and forms a portion of the upper faces of the pair of side portions21A and21B. The height position of the fourth upper face28dis set lower than the position of the third upper face28c.

Out of the first upper face28ato the fourth upper face28dthat have the above configuration, the first upper face28aincludes a first spacer receiving portion24. The first spacer receiving portion24is provided as a portion for receiving the spacer19(seeFIG. 19) from below the spacer19. The first spacer receiving portion24is formed by at least a portion of the first upper face28a. In this embodiment, the first spacer receiving portion24is provided in the front portion28a1and the rear portion28a2of the first upper face28a. In this embodiment, the first spacer receiving portion24is constituted by portions of the front portion28a1and the rear portion28a2of the first upper face28aof the central portion20, namely portions thereof on which the spacer19can be put. According to this configuration, the spacer19is received by the first spacer receiving portion24in two portions on the front end side and rear end side, and can thus be received in a more stable orientation by the template12. The guide receiving portion25is arranged adjacent to the first spacer receiving portion24. The guide receiving portion25is provided as a portion for receiving the keel punch guide13.

The guide receiving portion25has a front portion25a, a rear portion25b, and side portions25cand25d, and is configured to support the keel punch guide13in a stable orientation by supporting the keel punch guide13at four points (seeFIG. 5).

The front portion25aof the guide receiving portion25is formed in the front portion28a1of the first upper face28a. In this embodiment, the rear portion25bof the guide receiving portion25is formed in the rear portion28a2of the first upper face28a. In this embodiment, the side portions25cand25dof the guide receiving portion25are formed in the third upper face28c. The side portions25cand25dof the guide receiving portion25are constituted by the third upper face28con which the keel punch guide13can be placed, around the boundary with the fourth upper face28d. The keel punch insertion hole portion26is formed adjacent to the guide receiving portion25having the above configuration.

The keel punch insertion hole portion26is formed as a portion through which the keel punch16(seeFIG. 1) passes when being inserted into the proximal portion101of the tibia100. The keel punch insertion hole portion26has a circular portion26aand a pair of wing-shaped portions26bthat extend from this circular portion. The circular portion26ais a hole portion surrounded by the rear end edge of the front portion28a1of the first upper face28a, the front end edge of the rear portion28a2, and the inner end edge of the second upper face28b. The two wing-shaped portions26bare substantially straight portions, when seen in a plan view, and extend from the second upper face28bto the fourth upper face28d. According to the above configuration, the keel punch insertion hole portion26is formed into a substantially V-shape when seen in a plan view. The fixing pin insertion hole portions30ato30fare formed at positions that do not overlap the keel punch insertion hole portion26.

The fixing pin insertion hole portions30ato30fare provided as penetrating portions through which fixing pins31(fixing member; indicated by a dash-double dot line inFIG. 4) for fixing the template12to the proximal portion101of the tibia100pass. A plurality of fixing pin insertion hole portions30ato30fare provided, and are provided in six portions in this embodiment. This embodiment employs a configuration in which the positions of the fixing pin insertion hole portions30ato30fdiffer from the position of the spacer19(the first spacer receiving portion24) in the inward-outward direction X1.

The fixing pin insertion hole portions30aand30bare arranged at end portions, in the inward-outward direction X1, of front portions of the pair of side portions21A and21B of the template12, and are open in the third upper face28c. The fixing pin insertion hole portions30cand30dare arranged in the fourth upper face28dclose to front portions thereof in the pair of side portions21A and21B of the template12, and are open in the fourth upper face28d. The fixing pin insertion hole portions30eand30fare arranged in the fourth upper face28dclose to rear portions thereof in pair of side portions21A and21B of the template12, and are open in the fourth upper face28d.

FIG. 5is a perspective view showing a state in which the template12and the keel punch guide13have been attached to the proximal portion101of the tibia100.FIGS. 6A and 6Bare perspective views of the keel punch guide13.FIG. 6Cis a plan view of the keel punch guide13.FIG. 6Dis a front elevational view of the keel punch guide13.

Referring toFIGS. 3, 5, and 6A to 6D, the keel punch guide13is attached to the template12in a state of having been placed on the cut bone surface102of the tibia100. The keel punch guide13is a member for guiding the keel punch16when the keel punch16is inserted into the proximal portion101. The keel punch guide13is formed into a V-shape when seen in a plan view.

The keel punch guide13includes a tubular portion131and a pair of wing portions132, which are provided to allow the keel punch16to pass therethrough and are arranged in alignment with the template12.

The tubular portion131is provided as a portion through which a tubular portion161of the keel punch16is to pass. In this embodiment, the tubular portion131is formed into a cylindrical shape. The tubular portion131includes a high-wall portion34, which is formed on the front side of the keel punch guide13, and a low-wall portion35, which is formed on the rear side of the keel punch guide13.

The high-wall portion34is a portion formed into an arc shape corresponding to approximately two-thirds of a circle, when seen in a plan view, and is formed into a shape that protrudes forward. A ball plunger36, which serves as a positioning mechanism, is provided in the high-wall portion34. The ball plunger36is provided to define the position of the keel punch handle17(seeFIG. 1) in the rotational direction, relative to the keel punch guide13. The ball plunger36has a configuration in which a spring and a ball are accommodated in a housing that protrudes from the high-wall portion34toward an outer-circumferential face of the high-wall portion34. The ball in the ball plunger36is partially exposed in an inner-circumferential face of the high-wall portion34. When subjected to an applied pressure, the ball in the ball plunger36withdraws into the housing against elastic repulsive force of the spring. A passage37is formed in a lower end portion of a front end portion of the outer-circumferential portion of the high-wall portion34.

The passage37is a portion through which the connecting portion11dof the template handle11for operating the template12passes when the template handle11is removed from the template12. This passage37is arranged above the connected portion22of the template12when the keel punch guide13is attached to the template12. The passage37is formed into a groove shape that extends upward from a lower end of the high-wall portion34, and is open forward. The height and the width (the length in the inward-outward direction X1) of the passage37are set such that the connecting portion11dof the template handle11can pass. The low-wall portion35is arranged rearward of the high-wall portion34.

The low-wall portion35is a portion formed into an arc shape corresponding to approximately one-thirds of a circle, when seen in a plan view, and is formed into a shape that protrudes rearward. The height of the low-wall portion35is set lower than the height of the high-wall portion34. The high-wall portion34and the low-wall portion35are connected to each other via the pair of wing portions132.

The pair of wing portions132are provided as portions through which a later-described pair of wing portions162of the keel punch16passes. The pair of wing portions132is formed symmetrically in the inward-outward direction X1. Each of the wing portions132has a shape that extends rearward and outward in the inward-outward direction X1from a corresponding end portion of the high-wall portion34in the inward-outward direction X1, and then extends forward and inward in the inward-outward direction X1to be connected to a corresponding end portion of the low-wall portion35. Upper faces of the wing portions132extend such that the height positions thereof are lower as they extend farther from the tubular portion131. Lower faces of the wing portions132are partially flat.

Studs38ato38dare formed in a bottom face of the tubular portion131. The studs38ato38dare provided to fix the keel punch guide13to the proximal portion101of the tibia100, and are formed into shaft shapes extending downward from the tubular portion131so as to be able to be stuck into the proximal portion101. The studs38aand38bare formed in the high-wall portion34of the tubular portion131, and are arranged so as to be able to pass through the corresponding stud insertion hole portions27aand27bin the template12. The studs38cand38dare formed in the low-wall portion35of the tubular portion131, and are arranged so as to be able to pass through the corresponding stud insertion hole portions27cand27dof the template12.

The keel punch guide13is supported by the template12, with the studs38ato38dfixed to the tibia100. Specifically, at a bottom face of the high-wall portion34of the tubular portion131, a portion around the passage37is received by the front portion25a(the first spacer receiving portion24) of the guide receiving portion25of the template12. Also, at a bottom face of the low-wall portion35of the tubular portion131, a portion around the studs38cand38dis received by the rear portion25b(the first spacer receiving portion24) of the guide receiving portion25of the template12. Bottom faces of leading end portions of the pair of wing portions132of the keel punch guide13are received by the side portions25cand25dof the guide receiving portion25.

Positioning protrusions39ato39dfor positioning the keel punch guide13on the template12are formed in a bottom face of the keel punch guide13. The positioning protrusions39aand39bare portions that protrude downward from bottom faces of front portions of the pair of wing portions132. These positioning protrusions39aand39bare attached at positions at which the positioning protrusions39aand39bcan sandwich the central portion20of the template12in the inward-outward direction X1. The positioning protrusions39cand39dare portions that protrude downward from bottom faces of rear portions of the pair of wing portions132. These positioning protrusions39cand39dare attached at positions at which the positioning protrusions39cand39dcan sandwich the central portion20of the template12in the inward-outward direction X1.

According to the above configuration, as a result of the positioning protrusions39aand39band the positioning protrusions39cand39dbeing arranged so as to sandwich the central portion20, the keel punch guide13is positioned in the inward-outward direction X1relative to the template12. In a state in which the keel punch guide13is arranged on the template12, a hole portion is formed in the proximal portion101of the tibia100by the drill14.

The drill14is formed into a shaft shape, and has a diameter that allows the drill14to pass through the tubular portion131of the keel punch guide13. A cutter portion is formed at a leading end of the drill14, and is configured to cut the proximal portion101of the tibia100. A connecting portion, which is to be connected to a driving source such as an electric actuator (not shown), is formed at a base end portion of the drill14. The stopper15is disposed in an intermediate portion of the drill14on the base end side. The stopper15is provided to define the depth to which the drill14is inserted into the tubular portion131of the keel punch guide13, i.e. the depth to which the drill14is inserted into the proximal portion101of the tibia100. The stopper15is provided as a cylindrical element that is removable from the drill14, and has a cylindrical member and a holding member that are connected to each other in a loose-fit state, via a shaft portion15a(seeFIG. 5). The holding portion has a pair of ring-shaped portions that sandwich the cylindrical member in the thickness direction, and a connecting portion that integrally connects the two ring-shaped portions to each other. The connecting portion is configured to integrally connect portions of outer-circumferential edge portions of the two ring-shaped portions to each other, in the axial direction of the cylindrical portion. The cylindrical member is held by the holding member, in a state of being sandwiched by the pair of ring-shaped portions of the holding member. An elongated hole, into which the shaft portion15ais inserted in a loose-fit state, is provided in the cylindrical member. In a state in which the cylindrical member is sandwiched and held between the pair of ring-shaped portions of the holding member, the shaft portion15ais fixed to the holding member at a position at which the shaft portion15ais inserted into the elongated hole in the cylindrical member. Thus, the cylindrical member is connected, in a loose-fit state, to the holding member via the shaft portion15a. A protrusion is provided on an inner-circumferential face of the cylindrical member, and is slidably fitted into a groove that is provided on an outer-circumferential face of a portion of the drill14on the base end side and extends in the axial direction of the drill14. Note that an inner hole of the cylindrical member is configured as an elliptical hole, with a direction in which the protrusion extends serving as a major axis direction.

The stopper15can be removably disposed onto the drill14by inserting the portion of the drill14on the base end side into inner holes of the pair of ring-shaped portions of the holding portion and the inner hole of the cylindrical member, in a state in which the protrusion on the inner-circumferential face of the cylindrical member is fitted into the groove in the drill14. The groove in the drill14is provided with a mating hole, which is recessed inward into the drill14at a predetermined position on a bottom portion of the groove. The stopper15is positioned in the axial direction relative to the drill14at a position corresponding to the aforementioned mating hole, in a state in which the portion of the drill14on the base end side has been inserted in the inner holes of the pair of ring-shaped portions and the inner hole of the cylindrical member. More specifically, an operation is performed to relatively move the cylindrical member with respect to the holding member and the drill14to push the cylindrical member toward the axis of the drill14so as to mate the protrusion on the inner-circumferential face of the cylindrical member with the aforementioned mating hole. At this time, the shaft portion15afixed to the holding member is inserted, in a loose-fit state, in the elongated hole in the cylindrical member, and the portion of the drill14on the base end side is inserted in the elliptical hole inside the cylindrical member. Accordingly, relative movement of the cylindrical member with respect to the drill14is allowed. Then, the protrusion on the inner-circumferential face of the cylindrical member of the stopper15is mated with the mating hole in the drill14, and thus, the stopper15is positioned in the axial direction relative to the drill14. The drill14is inserted into the keel punch guide13until the stopper15comes into contact with an opening edge portion131aof the high-wall portion34of the tubular portion131of the keel punch guide13. After a preparatory hole has been formed in the proximal portion101of the tibia100by the drill14, the keel punch16attached to the keel punch handle17is inserted, through the keel punch guide13, into the proximal portion101of the tibia100, as shown inFIG. 7.

FIG. 7is a perspective view showing the template handle11, the template12, the keel punch handle17, the keel punch guide13, and the keel punch16, together with the tibia100.FIG. 8Ais a side view of a main portion of the keel punch handle17.FIG. 8Bis a perspective view of the main portion of the keel punch handle17. Referring toFIGS. 7, 8A, and 8B, the keel punch handle17is used by an operator to operate the keel punch16, and is also used by an operator to operate the keel punch guide13. The keel punch handle17is an elongated member that extends axially.

The keel punch handle17has a flat portion41and a shaft portion42.

The flat portion41is a flat plate-shaped portion formed in a base end portion of the keel punch handle17, and extends orthogonally to the axial direction of the shaft portion42. The flat portion41is a portion that is to be hit with a hammer by an operator when driving the keel punch16into the tibia100using the hammer, for example. The shaft portion42extends downward from the flat portion41.

The shaft portion42has a grip portion43, a second stopper44, and an insertion end portion45that is formed on a leading end side of the second stopper44.

The grip portion43is an elongated portion that is to be gripped by an operator, and an intermediate portion, in the axial direction, of the grip portion43bulges radially outward. The flat portion41is arranged in a base end portion of the grip portion43, and the second stopper44is arranged in a leading end portion of the grip portion43.

The second stopper44is provided as a circular plate-shaped portion that is to be received by the opening edge portion131aof the tubular portion131, and extends in a direction orthogonal to the axial direction of the keel punch handle17. As a result of the second stopper44being received by the opening edge portion131a, the position of the keel punch handle17in the axial direction relative to the keel punch guide13is defined.

The insertion end portion45includes a portion that is to be inserted into the tubular portion161of the keel punch16. The insertion end portion45is provided as a portion that is to be inserted into the tubular portion131of the keel punch guide13.

The insertion end portion45has first to fourth portions45ato45d.

The first portion45ais a circular column-shaped portion that is continuous with the second stopper44. Connected portions45fare provided on an outer-circumferential face of the first portion45a. The connected portions45fare groove-shaped portions into which the ball in the ball plunger36, which is a mechanism for positioning the keel punch guide13, is fitted. The connected portions45fextend in the axial direction of the keel punch handle17, and are open in a lower end face of the first portion45a. One or more (in this embodiment, four) connected portions45fare provided at an even pitch in the circumferential direction of the first portion45a.

When the ball in the ball plunger36has entered a connected portion45f, and the value of the torque that acts on the keel punch handle17is a predetermined value or less, the ball in the ball plunger36restricts relative rotation of the keel punch guide13. The second portion45bextends from a leading end of the first portion45a.

The second portion45bis formed into a circular column shape with a diameter smaller than the diameter of the first portion45a, and is configured to be arranged within the tubular portion131of the keel punch guide13. A leading end face of the second portion45bincludes a first stopper40, which is to be received by the opening edge portion161aof the tubular portion161of the keel punch16. The first stopper40is a flat face. The third portion45cextends from a leading end of the second portion45b.

The third portion45cis a narrow shaft-shaped portion, and has a diameter that is set smaller than the diameter of the second portion45b. The fourth portion45dis formed at a leading end of the third portion45c. The fourth portion45dconstitutes a leading end portion of the keel punch handle17, and also constitutes a portion of a later-described first connection mechanism46.

Next, a description will be given of a more detailed configuration of the keel punch16that is operated by the keel punch handle17.FIG. 9Ais a plan view of the keel punch16.FIG. 9Bis a front elevational view of a main portion, showing a state in which the keel punch16has been connected to the keel punch handle17.FIG. 9Cis a cross-sectional view taken along a line IXC-IXC inFIG. 9B.FIG. 10Ais a side view of a main portion, showing a state in which the keel punch16has been connected to the keel punch handle17.FIG. 10Bis a cross-sectional view taken along a line XB-XB inFIG. 10A.

Referring toFIGS. 7, 9A to 9C, 10A, and 10B, the keel punch16is provided to form a hole portion for embedding a stud of a tray (not shown) of the tibial component into the proximal portion101of the tibia100, for example. The keel punch16is driven into the proximal portion101in which a preparatory hole has been formed by the drill14. The keel punch16is formed into a V-shape when seen in a plan view. The keel punch16is formed symmetrically in the internal-external direction X1.

The keel punch16has the tubular portion161and the pair of wing portions162.

In this embodiment, the tubular portion161is formed into a cylindrical shape, and one end portion thereof is open upward. A portion of the tubular portion161on a leading end side is closed. Positioning portions163are formed in the tubular portion161. The positioning portions163are provided to define the position of the keel punch handle17in the circumferential direction relative to the keel punch16. A plurality of (in this embodiment, two) positioning portions163are provided at equal intervals in the circumferential direction of the tubular portion161. In this embodiment, the positioning portions163are through-holes formed in the tubular portion161.

The pair of wing portions162extends from an outer-circumferential portion of the tubular portion161. The pair of wing portions162is provided as plate-shaped members that have cutters in their lower faces. The wing portions162are formed such that the lower faces extend upward as they extend farther from the tubular portion161, and also extend rearward as they extend farther from the tubular portion161.

The first connection mechanism46is configured to allow the keel punch handle17and the keel punch16, which have the above configuration, to be attached to and detached from each other, and to prevent the keel punch handle17from coming out from the keel punch16. In this embodiment, the first connection mechanism46is arranged within the tubular portion161of the keel punch16when the keel punch16is connected to the keel punch handle17.

The first connection mechanism46includes a first protrusion46a, which is formed in either one of the keel punch handle17and the keel punch16and serves as a first connecting portion, and first projections46b, which are formed in the other one of the keel punch handle17and the keel punch16and serve as a first connected portion.

More specifically, the first protrusion46ais formed in either one of the insertion end portion45and the tubular portion161, and the first projections46bthat are to be connected to the first protrusion46aare formed in the other one of the insertion end portion45and the tubular portion161. In this embodiment, the first protrusion46ais formed in the fourth portion45dof the insertion end portion45, and the first projections46bare formed in the tubular portion161. Note that the first projections (first connected portion) may be formed in the fourth portion45dof the insertion end portion45, and the first protrusion (first connecting portion) may be formed in the tubular portion161.

The first protrusion46ais provided as a leading end portion of the keel punch handle17. In this embodiment, the fourth portion45dof the insertion end portion45is formed by the first protrusion46a. The first protrusion46ais arranged within an area surrounded by an outline of the second portion45bwhen seen from below. The first protrusion46ais formed into an elongated rectangular column shape, and has a rectangular outline portion in its cross-section orthogonal to the axial direction of the keel punch handle17. The first protrusion46ais arranged coaxially with the first portion45ato the third portion45cof the insertion end portion45. In this embodiment, the first protrusion46ais formed into an elongated shape with a lengthwise direction being the lengthwise direction of the flat portion41(the left-right direction inFIG. 9B), and a widthwise direction being the widthwise direction of the flat portion41(the direction orthogonal to the paper plane inFIG. 9B), when seen from the side.

The first projections46bare formed on an inner-circumferential face164of the tubular portion161, within the tubular portion161of the keel punch16. The first projections46bprotrude inward of the tubular portion161from the inner-circumferential face164so as to partially block the inner-circumferential face164, which has a circular shape, of the tubular portion161, when seen in a plan view. In this embodiment, the first projections46bare configured to allow the first protrusion46ato pass between the first projections46bwhen the first protrusion46ais at a predetermined position in the circumferential direction of the keel punch16, and to restrict the first protrusion46afrom passing between the first projections46bwhen the first protrusion46ais at another position in the circumferential direction.

In this embodiment, the first projections46bare formed symmetrically with respect to each other when seen in a plan view, and have a shape that includes a portion of a circle. More specifically, one of the first projections46bhas an outline shape demarcated by a line that extends straight to connect two points on the inner-circumferential face164when seen in a plan view, and a portion of the inner-circumferential face164that is demarcated by this line. The other one of the first projections46bhas a similar shape. Thus, the first projections46bare provided to form a pair at a pitch of 180 degrees on the inner-circumferential face164of the tubular portion161. According to this configuration, a passage hole portion46cis formed in the tubular portion161, the passage hole portion46chaving a cross-sectional shape that matches the cross-sectional shape (elongated rectangular shape) of the first protrusion46a. The thickness of the first projections46b(the thickness of the keel punch16in the axial direction) is set smaller than the length of the third portion45cof the insertion end portion45of the keel punch handle17.

Also, the first connection mechanism46includes a ball plunger46d, which serves as a positioning mechanism. The ball plunger46dis provided to define the position of the keel punch handle17in the rotational direction relative to the keel punch16. The ball plunger46dhas a configuration in which a spring and a ball are accommodated in a space formed in the first protrusion46a. The ball in the ball plunger46dis partially exposed in a side face of the first protrusion46athat has a smaller width. When subjected to an applied pressure, the ball in the ball plunger46dwithdraws into the first protrusion46aagainst elastic repulsive force of the spring. The ball in the ball plunger46dis configured to mate with either one of the positioning portions163within the tubular portion161, and this mating can notify an operator that the keel punch handle17has reached a locking position relative to the keel punch16.

According to the above configuration, when the keel punch handle17is connected to the keel punch16, that is, when the insertion end portion45is inserted into the keel punch16, the first protrusion46ais inserted into the tubular portion161so as to pass between the first projections46b. Then, the first stopper40is received by the opening edge portion161aof the tubular portion161. When the first stopper40is at the position at which it is received by the opening edge portion161a, the position of the first protrusion46ais set on the distal side of the position of the space between the pair of the first projections46bwithin the tubular portion161. The third portion45cof the insertion end portion45is located between the pair of first projections46b.

In a state in which the insertion end portion45has been inserted in the tubular portion161, the first protrusion46ais connected to and disconnected from the first projections46bthrough relative displacement of the keel punch handle17and the keel punch16. In this embodiment, the aforementioned connection and disconnection are performed by moving the keel punch handle17in a predetermined first direction D1, which differs from the axial direction of the keel punch handle17, relative to the keel punch16.

The first direction D1includes a first connecting direction D11for connecting the keel punch handle17to the keel punch16, and a first disconnecting direction D12for canceling this connection that is opposite to the first connecting direction D11. In this embodiment, the first direction D1is a rotational direction around an axis parallel to the axial direction of the keel punch handle17. Note that the first direction D1may alternatively be another direction, such as a helical direction around the aforementioned axis.

In this embodiment, the keel punch handle17is connected (locked) to the keel punch16as a result of the keel punch handle17being rotated in the first connecting direction D11by approximately 90 degrees relative to the keel punch16, with the insertion end portion45inserted in the tubular portion161. At this time, a portion of the first protrusion46afaces the pair of first projections46bin the axial direction. Also, a recession formed in the third portion45cof the insertion end portion45and the first protrusion46awork together to hold each of the pair of first projections46bfrom two opposite sides. As a result, the keel punch handle17and the keel punch16can be displaced integrally. At this time, the ball in the ball plunger46dis fitted to one of the positioning portions163of the tubular portion161.

If, in this state, the keel punch handle17is rotated by 90 degrees in the first disconnecting direction D12, the ball in the ball plunger46drotates so as to come out from the positioning portion163. Then, the first protrusion46bassumes an orientation that allows the first protrusion46ato pass between the pair of projections46b, and the keel punch handle17can be pulled out of the keel punch16.

FIG. 11is a perspective view showing a state in which the keel punch handle17has been connected to the keel punch guide13.FIG. 12Ais a side view showing a state in which the keel punch handle17has been connected to the keel punch guide13.FIG. 12Bis a cross-sectional view taken along a line XIIB-XIIB inFIG. 12A.FIG. 13is a side view showing a state in which the keel punch handle17has been connected to the keel punch16, together with the keel punch guide13, and partially shows cross-sections of these components.

Referring toFIGS. 6C, 11, 12A, 12B, and 13, a second connection mechanism47is configured to enable the keel punch handle17to be attached to and detached from the keel punch guide13, and to integrally connect the keel punch handle17to the keel punch guide13. In this embodiment, when the keel punch guide13is connected to the keel punch handle17, the second connection mechanism47is arranged within the tubular portion131of the keel punch guide13.

The second connection mechanism47includes second protrusions47a, which serve as a second connecting portion formed in either one of the keel punch handle17and the keel punch guide13, and second connected portions47band47c, which are formed in the other one of the keel punch handle17and the keel punch guide13.

More specifically, the second protrusions47aare formed in either one of the insertion end portion45and the tubular portion131, and the second connected portions47band47cthat are to be connected to the second protrusions47aare formed in the other one of the insertion end portion45and the tubular portion131. In this embodiment, a pair of second protrusions47ais formed in the second portion45bof the insertion end portion45, and the second connected portions47band47care formed in the tubular portion131. Note that the number of second protrusions47aand the number of second connected portions47band47cmay be one. A configuration may alternatively be employed in which the second connected portions are formed in the second portion45bof the insertion end portion45, and the second protrusions (second connecting portions) are formed in the tubular portion131.

The second protrusions47aare small piece portions that are formed on an outer-circumferential face of the second portion45bof the insertion end portion45and protrude radially outward from the second portion45b. The second protrusions47aare arranged at an even pitch of 180 degrees in the circumferential direction of the keel punch handle17. The second protrusions47aare aligned with each other at positions distant, on the second stopper44side, from the first protrusion46ain the axial direction of the keel punch handle17. The second protrusions47aextend in the widthwise direction of the first protrusion46a(the left-right direction inFIG. 13). When the keel punch handle17is connected to the keel punch16(i.e. at the time shown inFIG. 13), the second protrusions47aare located outside of the keel punch16.

The second connected portions47band47care formed on an inner-circumferential face of the tubular portion131of the keel punch guide13. The second connected portion47bis arranged in the high-wall portion34of the tubular portion131, and the second connected portion47cis arranged in the low-wall portion35of the tubular portion131.

The second connected portion47bis arranged on the lower side of the inner-circumferential face of the high-wall portion34, and is formed into a shape protruding radially inward from this inner-circumferential face. The second connected portion47cis arranged over the substantially entire area of an inner-circumferential face of the low-wall portion35, and is formed into a shape protruding radially inward from this inner-circumferential face. In this embodiment, the height (the length in the axial direction) of the second connected portion47band the height (the length in the axial direction) of the second connected portion47care set to substantially the same length. The second connected portions47band47care formed substantially symmetrically in the front-rear direction Y1.

The second connected portion47bincludes a vertical groove portion47dand a lateral groove portion47e. The second connected portion47cincludes a vertical groove portion47fand a lateral groove portion47g.

The vertical groove portions47dand47fare groove portions that extend in the axial direction of the tubular portion131, and have shapes that are open in the axial direction of the tubular portion131and radially inward. The groove width of the vertical groove portions47dand47f(the length of the tubular portion131in the circumferential direction) is set such that the corresponding second protrusions47acan pass therethrough. The groove width of the vertical groove portion47d(seeFIG. 6C) is set such that projections165formed on the opening end side of the keel punch16can pass therethrough. The vertical groove portions47dand47fare provided as portions through which the second protrusions47acan pass therethrough in the axial direction of the tubular portion131. The arrangement pitch of the vertical groove portions47dand47fin the circumferential direction of the tubular portion131are set to be the same as the arrangement pitch of the second protrusions47ain the circumferential direction of the keel punch handle17. In this embodiment, the vertical groove portions47dand47fare arranged in a front end portion and a rear end portion, respectively, of the inner-circumferential face of the tubular portion131. The lateral groove portion47eis formed to as to intersect the vertical groove portion47d, and the lateral groove portion47gis formed so as to intersect the vertical groove portion47f.

The lateral groove portions47eand47gare provided to be mated with the corresponding second protrusions47a, thereby integrally connecting the keel punch handle17to the keel punch guide13. The lateral groove portions47eand47gare groove portions that extend in the circumferential direction of the tubular portion131, and extend so as to intersect (in this embodiment, so as to be orthogonal to) the corresponding vertical groove portions47dand47f. Thus, the lateral groove portions47eand47gspan both sides of the corresponding vertical groove portions47dand47fin the circumferential direction. In this embodiment, the lateral groove portions47eand47gare formed over the entire area of the corresponding high-wall portion34and low-wall portion35in the circumferential direction.

The distance in the axial direction of the keel punch guide13from the opening edge portion131aof the tubular portion131to the lateral groove portions47eand47gis set to be substantially the same as the distance in the axial direction of the keel punch handle17from the second stopper44to the second protrusions47a.

According to the above configuration, when the keel punch handle17is connected to the keel punch guide13, that is, when the insertion end portion45is inserted into the keel punch guide13, the second protrusions47apass through the corresponding vertical groove portions47dand47f. Then, the second stopper44is received by the opening edge portion131aof the tubular portion131. When the second stopper44is received by the opening edge portion131a, the second protrusions47acan enter and exit from the corresponding lateral groove portions47eand47g.

In a state in which the insertion end portion45has been inserted in the tubular portion131, the second protrusions47aare connected to and disconnected from the corresponding lateral groove portions47eand47gof the second connected portions47band47cthrough relative displacement of the keel punch handle17and the keel punch guide13. In this embodiment, the aforementioned connection and disconnection are performed by moving the keel punch handle17in a predetermined second direction D2, which differs from the axial direction of the keel punch handle17, relative to the keel punch guide13.

The second direction D2includes a second connecting direction D21for connecting the keel punch handle17to the keel punch guide13, and a second disconnecting direction D22for canceling this connection that is opposite to the second connecting direction D21. In this embodiment, the second direction D2is a rotational direction around an axis parallel to the axial direction of the keel punch handle17. Note that the second direction may alternatively be another direction, such as a helical direction around the aforementioned axis.

In this embodiment, the keel punch handle17is connected (locked) to the keel punch guide13as a result of the keel punch handle17being rotated in the second connecting direction D21by approximately 90 degrees relative to the keel punch guide13, with the insertion end portion45inserted in the tubular portion131. At this time, the second protrusions47aenter the corresponding lateral groove portions47eand47gfrom the corresponding vertical groove portions47dand47f. As a result, the second protrusions47aare fitted into the corresponding lateral groove portions47eand47g, and enter a state of being held from above and below by the lateral groove portions47eand47g, respectively. Furthermore, as a result of the ball in the ball plunger36in the keel punch guide13being received by the connected portion45fof the keel punch handle17, the keel punch handle17is positioned in the circumferential direction relative to the keel punch guide13. As a result, the keel punch handle17and the keel punch guide13can be displaced integrally.

If, in this state, the keel punch handle17is rotated by 90 degrees in the second disconnecting direction D22, the keel punch handle17rotates such that the ball in the ball plunger36comes out from the connected portion45f. Also, the second protrusions47areturn to the corresponding vertical groove portions47dand47f. Thus, the keel punch handle17can be pulled out of the keel punch guide13.

In this embodiment, the first disconnecting direction D12and the second connecting direction D21are the same direction. With this configuration, it is possible to simultaneously cancel the connection between the keel punch handle17and the keel punch16through the first connection mechanism46and connect the keel punch handle17to the keel punch guide13through the second connection mechanism47, by displacing the keel punch handle17in one direction relative to the keel punch16and the keel punch guide13.

The first connecting direction D11is opposite to the second connecting direction D21. That is to say, the direction (the first connecting direction D11) in which the keel punch handle17is displaced relative to the keel punch16in order to connect the keel punch handle17to the keel punch16through the first connection mechanism46is set to be opposite to the direction (the second connecting direction D21) in which the keel punch handle17is displaced relative to the keel punch guide13in order to connect the keel punch handle17to the keel punch guide13through the second connection mechanism47.

FIG. 14Ais a perspective view showing a state in which the template12is attached to the proximal portion101of the tibia100, before the tibial insert trial18is attached to the template12.FIG. 14Bis a perspective view showing a state in which the template12has been attached to the proximal portion101of the tibia100, and the tibial insert trial18has been attached to the template12.FIG. 15Ais a plan view of the template12and the tibial insert trial18.FIG. 15Bis a cross-sectional view taken along a line XVB-XVB inFIG. 15A.FIG. 16is a perspective view of the tibial insert trial18.

Referring toFIGS. 14A and 14B, 15A and 15B, and 16, the tibial insert trial18is a member that is to be temporarily attached to the proximal portion101of the tibia100when a tibial component (not shown) is selected. The tibial insert trial18is formed into a shape with a rear end portion of a central portion in the inward-outward direction X1being recessed forward.

The tibial insert trial18has a pair of tibial joint surfaces48A and48B, which are arranged in the inward-outward direction X1, a post49, which is arranged between these tibial joint surfaces48A and48B, and a bottom portion50.

In this embodiment, a plurality of tibial insert trials18with different shapes of the tibial joint surfaces48A and48B and different shapes of the post49are provided. A tibial insert trial18will be described as an example. Note that other tibial insert trials have the same configuration except that the shape of the tibial joint surfaces and the shape of the post differ.

The two tibial joint surfaces48A and48B are portions that mimic tibial joint surfaces of a tibial component, and have a recessed shape similar to that of the tibial joint surfaces of the tibial component. The pair of tibial joint surfaces48A and48B and the post49face upward. The post49is a portion that mimics a post of a tibial component, and has a columnar shape similar to that of the post of the tibial component.

The bottom portion50has second rails51A and51B, and a second spacer receiving portion52.

The second rails51A and51B are formed in a pair of protrusions53A and53B that protrude downward from the bottom portion50. The two protrusions53A and53B are spaced apart in the inward-outward direction X1, and are formed into tab shapes extending straight in the front-rear direction Y1. The second rails51A and51B are formed in an inner face of the pair of protrusions53A and53B, respectively, in the inward-outward direction X1, and extend straight in the front-rear direction Y1. Assuming that the central portion20of the template12is a first rail, the second rails51A and51B are arranged so as to sandwich the central portion20. With this configuration, the tibial insert trial18can slide in the front-rear direction Y1on the template12, with the second rails51A and51B sandwiching the central portion20(the first rail).

When the spacer19is not inserted between the template12and the tibial insert trial18, the pair of protrusions53A and53B are received by the third upper face28cof the template12. At this time, a gap is formed between the first spacer receiving portion24and the second spacer receiving portion52.

The pair of protrusions53A and53B is arranged between the central portion20and corresponding side end walls29A and29B of the template12, and is sandwiched between the central portion20and the corresponding side end walls29A and29B. Side end wall receiving portions54A and54B are formed in a rear portion of an end portion, in the inward-outward direction X1, of the bottom portion50of the tibial insert trial18. These side end wall receiving portions54A and54B are cutout portions configured to be placed on the corresponding side end walls29A and29B of the template12, and extend forward and rearward.

Intermediate portions of the side end wall receiving portions54A and54B each have a step portion, and the height position of rear portions of the side end wall receiving portions54A and54B is set higher than the height position of front portions of the side end wall receiving portions54A and54B. The side end wall receiving portions54A and54B are arranged to face the corresponding side end walls29A and29B, and can be received by the side end walls29A and29B, respectively. Recessions55A and55B are formed on the front side of the side end wall receiving portions54A and54B of the tibial insert trial18. When the tibial insert trial18is placed on the template12, the recessions55A and55B are configured to expose the fixing pin insertion hole portions30aand30b, which are arranged at a front end of the template12, upward and forward.

In a state in which the tibial insert trial18has been placed on the template12, a central portion, in the inward-outward direction X1, of the bottom portion50of the tibial insert trial18faces the first upper face28aof the template12in the up-down direction, and a flat face formed in the central portion of the bottom portion50includes the second spacer receiving portion52for receiving the spacer19. The second spacer receiving portion52is a portion that has a substantially T-shape when seen from below, and having a portion that extends in the front-rear direction Y1and is formed between the pair of protrusions53A and53B, and a portion arranged forward of the pair of protrusions53A and53B.

In a state in which the tibial insert trial18has been placed on the template12, the second spacer receiving portion52is substantially parallel to the first spacer receiving portion24of the template12. When the tibial insert trial18has been placed on the template12, an insertion space57, into which the spacer is to be inserted, is formed between the template12and the tibial insert trial18. The insertion space57is formed by the spacer receiving portions24and52, the central portion20(the first rail), and the second rails51A and51B. In the inward-outward direction X1, the length of the insertion space57is set larger than the length of a later-described body portion61of the spacer19.

FIG. 17Ais a perspective view showing the template12and the tibial insert trial18before the spacer19is attached thereto.FIG. 17Bis a perspective view showing the template12and the tibial insert trial18to which the spacer19has been attached.FIG. 18Ais a cross-sectional view showing a state in which the spacer19is arranged between the template12and the tibial insert trial18, and shows a cross-section taken along a section corresponding to a line XVB-XVB inFIG. 15A.FIG. 18Bis a front elevational view showing a state in which the spacer19is arranged between the template12and the tibial insert trial18.

Referring toFIGS. 17A and 17B, and 18A and 18B, the spacer19is provided to adjust the height position of the tibial insert trial18relative to the template12. Although a plurality of spacers with different thicknesses of the body portion are provided in this embodiment, the spacer19will be described as an example. Note that other spacers have the same configuration except that the thickness of the body portion differs from that of the spacer19.

The spacer19is configured to be arranged in a partial area of the template12in the inward-outward direction X1of a patient and in the central portion20of the template12, and inserted between the template12and the tibial insert trial18. Constituents of the spacer19other than a display portion of a later-described stopper63are formed symmetrically in the inward-outward direction X1.

The spacer19includes the body portion61, which is formed into a flat plate shape, and guide portions62A and62B and a stopper63, which are formed in a base end portion of the body portion61.

The body portion61is formed into a flat plate shape having a predetermined thickness, and extends in the front-rear direction Y1. The thickness of the body portion61is fixed, except in a leading end portion. The length of the body portion61in the inward-outward direction X1is set smaller than the length of the first spacer receiving portion24. A leading end of a central portion of the body portion61in the inward-outward direction X1has a shape that is recessed forward. Leading ends at both ends of the body portion61in the inward-outward direction are formed by tapered portions64A and64B. The tapered portions64A and64B are leading end portions of the spacer19in the inserting direction in which the spacer19is inserted into the insertion space57between the template12and the tibial insert trial18.

The tapered portions64A and64B are formed into shapes that are tapered and decrease in thickness toward the leading end of the spacer19. In the inward-outward direction X1, the length of the spacer insertion space57is set larger than the length of the body portion61of the spacer19. When the spacer19is inserted into the insertion space57, the tapered portions64A and64B are first inserted into the insertion space57. Then, the gap between the first spacer receiving portion24(the first upper face28a) of the template12and the second spacer receiving portion52of the tibial insert trial18is expanded by the tapered portions64A and64B, and then, a majority of the body portion61of the spacer19is inserted into the insertion space57.

During this inserting operation, the guide portions62A and62B are configured to respectively slidably mate with the rails58A and58B formed in the central portion20of the template12. The rails58A and58B are formed in portions in which the template12and the tibial insert trial18face each other. In this embodiment, the rails58A and58B that extend in the front-rear direction Y1are formed in the two end portions, in the inward-outward direction X1, of a front end portion of the central portion20of the template12. The rails58A and58B are formed into inclined shapes that extend outward in the inward-outward direction X1as they extend upward (from the third upper face28ctoward the first upper face28a). The rails58A and58B form a reverse tapered shape as a whole when seen from the front, and the gap therebetween expands upward. Note that, the rails58A and58B are not formed in the portions of the central portion20of the template12other than the front end portion thereof, as shown inFIG. 3.

The guide portions62A and62B of the spacer19are formed into hook-shaped portions that are formed in an outer end portion, in the inward-outward direction X1, of the base end portion of the body portion61. The guide portions62A and62B extend downward from the body portion61, and form a reverse tapered shape such that the gap therebetween narrows downward. After a portion of the spacer19has been inserted into the insertion space57, the guide portions62A and62B slidably mate with the corresponding rails58A and58B. If, in this state, the spacer19is further inserted into the insertion space57, the stopper63is received by a cutout portion18cof the tibial insert trial18. Thus, insertion of the space19into the insertion space57is complete.

The stopper63is arranged in the center, in the inward-outward direction X1, of the base end portion of the body portion61. The stopper63is formed into a block shape. A display portion is formed in a front face of the stopper63, the display portion displaying, by means of a mark or the like, the amount of change in the total thickness of the template12and the tibial insert trial18when the spacer19is inserted in the insertion space57. For example, if “+1 mm” is displayed on the display portion, the thickness of the body portion61of the spacer19is thicker, by 1 mm, than the thickness of the insertion space57in a state in which the spacer19is not inserted therein. In this case, if the spacer19is inserted into the insertion space57, the total thickness of the template12and the tibial insert trial18increases by 1 mm. The stopper63is fitted to the cutout portion18cformed in the front end portion of the tibial insert trial18. The cutout portion18cis a cutout portion that is open forward and upward. As a result of the cutout portion18creceiving the stopper63, the spacer19is restricted from being further inserted into the insertion space57.

A tilt restriction mechanism70is formed in a state in which the tibial insert trial18has been placed on the template12and the spacer19has been inserted in the insertion space57. The tilt restriction mechanism70is provided to restrict tilting of the tibial insert trial18relative to the template12around an axis of the tibia100that extends in the front-rear direction Y1. In this embodiment, the tilt restriction mechanism70is formed in front portions of the template12, the spacer19, and the tibial insert trial18.

Referring toFIG. 18B, the tilt restriction mechanism70includes first tilt restriction portions71A and71B, which are formed on the upper face side of the template12, second tilt restriction portions72A and72B, which are formed on the lower face side of the spacer19and can mate with the first tilt restriction portions71A and71B respectively, third tilt restriction portions73A and73B, which are formed on the upper face side of the spacer19, and fourth tilt restriction portions74A and74B, which are formed in the tibial insert trial18and can mate with the third tilt restriction portions73A and73B, respectively.

The first tilt restriction portions71A and71B are formed by the aforementioned rails58A and58B, respectively. The second tilt restricting portions72A and72B are formed by the aforementioned guide portions62A and62B. Thus, the first tilt restriction portions71A and71B and the second tilt restriction portions72A and72B also serve as a rail mechanism. The shapes of the first tilt restriction portions71A and71B are formed so as to match the shapes of the second tilt restriction portions72A and72B, when seen from the front.

The third tilt restriction portions73A and73B are formed in respective end portions, in the inward-outward direction X1, of the stopper63at a base end (front end) of the spacer19. The third tilt restriction portions73A and73B extend in the front-rear direction Y1, and are formed into inclined shapes that extend outward in the inward-outward direction X1as they extend upward from the body portion61. When seen from the front, the third tilt restriction portions73A and73B form a reverse tapered shape as a whole, and the gap therebetween expands as they extend upward.

The fourth tilt restriction portions74A and74B are formed at respective end portions, in the inward-outward direction X1, of the cutout portion18cof tibial insert trial18. The fourth tilt restriction portions74A and74B extend in the front-rear direction Y1, and are formed into inclined shapes that extend outward in the inward-outward direction X1as they extend upward. When seen from the front, the fourth tilt restriction portions74A and74B form a reverse tapered shape as a whole, and the gap therebetween expands as they extend upward. When seen from the front, the shapes of the third tilt restriction portions73A and73B are formed so as to match the shapes of the fourth tilt restriction portions74A and74B, respectively. Thus, the third tilt restriction portions73A and73B and the fourth tilt restriction portions74A and74B also serve as a stopper mechanism for preventing the spacer19from excessively entering the insertion space57.

Referring toFIGS. 17B and 18A, a position shift restriction mechanism80is provided to restrict a position shift of the tibial insert trial18in the inward-outward direction X1relative to the template12, in a state in which the tibial insert trial18has been placed on the template12.

The position shift restriction mechanism80has a first shift restriction portion81, which is formed in the template12, and a second shift restriction portion82, which is formed in the tibial insert trial18and faces the first shift restriction portion81in the inward-outward direction X1.

The first shift restriction portion81includes first inner shift restriction portions83A and83B, which are formed at respective end portions, in the inward-outward direction X1, of the central portion20of the template12, and first outer shift restriction portions84A and84B, which are formed in side end walls29A and29B, respectively, of the template12.

The second shift restriction portion82includes second inner shift restriction portions85A and85B, which are formed by portions of the pair of protrusions53A and53B of the tibial insert trial18, the portions forming the second rails51A and51B, and second outer shift restriction portions86A and86B, which are formed in end walls18aand18bof the tibial insert trial18. The height of the second inner shift restriction portions85A and85B from the bottom portion50of the tibial insert trial18is set larger than the thickness of the spacer19. Thus, even when the spacer19has been inserted in the insertion space57, the second inner shift restriction portions85A and85B sandwich the first inner shift restriction portions83A and83B in the inward-outward direction X1.

The length over which the first outer shift restriction portions84A and84B face the second outer shift restriction portions86A and86B in the up-down direction is set larger than the thickness of the spacer19. Thus, even when the spacer19has been inserted in the insertion space57, the first outer shift restriction portions84A and84B sandwich the second outer shift restriction portions86A and86B in the inward-outward direction X1. The second outer shift restriction portions86A and86B are sandwiched by the first outer shift restriction portions84A and84B in the inward-outward direction X1. According to the above configuration, the tibial insert trial18is restricted from being displaced in the inward-outward direction X1relative to the template12by the contact between the first inner shift restriction portions83A and83B and the corresponding second inner shift restriction portions85A and85B, or the contact between the first outer shift restriction portions84A and84B and the corresponding second outer shift restriction portions86A and86B.

A schematic configuration of the tibial trial attachment instrument assembly2is as described above. Next, main points of a procedure of an operation performed using the tibial trial attachment instrument assembly2will be described.FIG. 19is a flowchart showing an example of a procedure of an operation performed using a tibial trial attachment instrument assembly2. Note that, when a description is given with reference to the flowchart, diagrams other than the flowchart will also be referenced as appropriate.

When the tibial trial attachment instrument assembly2is used, an operator first puts the template12onto the cut bone surface102of the patient's tibia100using the template handle11, as shown inFIG. 2(step S1). Next, the operator fixes the studs38ato38dof the keel punch guide13to the tibia100through the corresponding stud insertion hole portions27ato27d(step S2). At this time, the operator may fix the template12to the tibia100using fixing pins (not shown).

Referring toFIG. 5, next, the operator inserts, into the keel punch guide13, the drill14to which the stopper15has been attached, and forms a preparatory hole in the proximal portion101of the tibia100(step S3). Next, referring toFIGS. 7 and 20A, the operator connects the keel punch handle17to the keel punch16by rotating the keel punch handle17by 90 degrees in the first connecting direction D11relative to the keel punch16(step S4), and then, the operator drives the keel punch16into the proximal portion101of the tibia100using the keel punch handle17and the keel punch guide13(step S5).

Next, by rotating the keel punch handle17by 90 degrees in the first disconnecting direction D12, i.e. the second connecting direction D21, the operator cancels connection between the keel punch handle17and the keel punch16through the first connection mechanism46, and connects the keel punch handle17to the keel punch guide13through the second connection mechanism47, as shown inFIG. 20B(step S6). In this state, the operator removes the keel punch handle17and the keel punch guide13from the tibia100(step S7).

Referring toFIGS. 17A and 17B, next, the operator attaches the tibial insert trial18onto the template12to perform a trial reduction (step S8). At this time, if tension of a patient's ligament is weak, the spacer19is inserted between the template12and the tibial insert trial18. When the spacer19is not inserted between the template12and the tibial insert trial18, a removal tool (not shown) is inserted between the template12and the tibial insert trial18.

As described above, according to the present embodiment, the template12, the keel punch guide13, the keel punch16, the keel punch handle17, and the tibial insert trial18are prepared as a single assembly. Accordingly, these instruments can be prepared collectively, which is less laborious than in the case of preparing these instruments separately. Accordingly, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

Also, according to the present embodiment, the first connection mechanism46can prevent the keel punch handle17from coming out from the keel punch16. Also, the keel punch handle17can be disconnected from the keel punch16when necessary. This makes it possible to suppress the case where the keel punch handle17and the keel punch16become hindrances. As a result, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, connection and disconnection between the keel punch handle17and the keel punch16can be performed with a simple configuration in which the keel punch handle17and the keel punch16are relatively moved in the first direction D1. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, the first direction D1is a rotational direction around an axis parallel to the axial direction of the keel punch handle17. According to this configuration, connection and disconnection between the keel punch handle17and the keel punch16can be performed with a simple configuration in which the keel punch handle17and the keel punch16are relatively rotated. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, connection and disconnection between the first protrusion46aand the first projections46bcan be performed with a simple operation, that is, relative movement of the keel punch handle17and the keel punch16.

According to the present embodiment, the keel punch handle17can be connected to the keel punch16by causing the first protrusion46a, which has a protruding shape, to be caught on the first projections46bformed within the tubular portion161of the keel punch16. Also, the aforementioned connection can be canceled by rotating the first protrusion46arelative to the first projections46b.

According to the present embodiment, since the first protrusion46acan be received by the pair of projections46b, the connection strength between the keel punch handle17and the keel punch16can be further increased. With this configuration, the operator does not need to pay attention to the connection strength between the keel punch handle17and the keel punch16when handling the keel punch handle17to which the keel punch16has been attached. As a result, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, the second connection mechanism47enables the keel punch handle17and the keel punch13to be integrally connected. This makes it possible to pull out the keel punch guide13using the keel punch handle17. Also, the keel punch handle17can be disconnected from the keel punch guide13when necessary. This makes it possible to suppress the case where the keel punch handle17and the keel punch guide13become hindrances. As a result, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, connection and disconnection between the keel punch handle17and the keel punch guide13can be performed with a simple configuration in which the keel punch handle17and the keel punch guide13are relatively moved in the second direction D2. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, the second direction D2is a rotational direction around an axis parallel to the axial direction of the keel punch handle17. According to this configuration, connection and disconnection between the keel punch handle17and the keel punch guide13can be performed with a simple configuration in which the keel punch handle17and the keel punch guide13are relatively rotated. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, connection and disconnection between the second protrusions47aand the second connected portions47band47ccan be performed with a simple operation, that is, relative movement of the keel punch handle17and the keel punch guide13.

According to the present embodiment, a single motion to displace the keel punch handle17in one direction (the first disconnecting direction D12and the second connecting direction D21) relative to the keel punch16and the keel punch guide13makes it possible to simultaneously cancel the connection between the keel punch handle17and the keel punch16through the first connection mechanism46and connect the keel punch handle17to the keel punch guide13through the second connection mechanism47. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient, through a reduction in the amount of labor in handling the keel punch handle17.

According to the present embodiment, the first connecting direction D11and the second connecting direction D21are set to opposite directions. According to this configuration, a configuration can be realized that makes it possible to simultaneously perform an operation to cancel the connection between the keel punch handle17and the keel punch16through the first connection mechanism46and an operation to connect the keel punch handle17to the keel punch guide13through the second connection mechanism47. It is thus possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient, through a reduction in the amount of labor in handling the keel punch handle17.

According to the present embodiment, even in a state in which the space around the tibia100is small because the template12has been attached to the patient's tibia100, the connecting portion11dof the template handle11can be removed from the template12through the passage37in the keel punch guide13. This makes it possible to more easily operate the template handle11. Accordingly, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, the spacer19for adjusting the height of the tibial insert trial18from the template12is included in the tibial trial attachment instrument assembly2. This eliminates the need for a laborious operation to prepare the spacer19, separately from other members of the tibial trial attachment instrument assembly2. Accordingly, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, the first connection mechanism46for connecting the keel punch handle17to the keel punch16is arranged within the tubular portion161of the keel punch16that is to be inserted into the patient's tibia100. Since the tubular portion161is configured to be inserted into the tibia100, the length of the tubular portion161in the axial direction and the diameter thereof can be secured to some extent. This makes it possible to sufficiently secure the space for arranging the first connection mechanism46within the tubular portion161. Accordingly, the first connection mechanism46can be formed to have a size that makes it possible to sufficiently secure the connection strength between the keel punch handle17and the keel punch16. Furthermore, the degree of freedom in designing of the structure (the first connection mechanism46) for connecting the keel punch handle17to the keel punch16can be further increased.

According to the present embodiment, the first protrusion46acan be connected to the first projections46bby inserting the insertion end portion45of the keel punch handle17into the tubular portion161. This simple configuration of the first connection mechanism46makes it possible to form the first connection mechanism46to have a size with which the connection strength between the keel punch handle17and the keel punch16can be secured sufficiently. Furthermore, the degree of freedom in designing of the structure (the first connection mechanism46) for connecting the keel punch handle17to the keel punch16can be further increased.

According to the present embodiment, connection and disconnection between the first protrusion46aand the first projections46bcan be performed with a simple configuration in which the keel punch handle17and the keel punch16are relatively displaced.

According to the present embodiment, the first connection mechanism46has a connection structure using a protrusion (the first protrusion46a). This configuration makes it possible to further increase the strength of the first protrusion46ain the first connection mechanism46, by employing a simple protruding shape.

According to the present embodiment, since the first protrusion46acan be received by the pair of projections46b, the connection strength between the keel punch handle17and the keel punch16can be further increased.

According to the present embodiment, connection between the keel punch handle17and the keel punch16through the first connection mechanism46can be realized by inserting the keel punch handle17into the keel punch16until the first stopper40of the keel punch handle17is received by the opening edge portion161aof the tubular portion161, and thereafter displacing the keel punch handle17relative to the keel punch16. Thus, the amount of insertion of the keel punch handle17into the keel punch16can be defined by the second stopper44.

According to the present embodiment, only a single component, namely the spacer19, is needed to adjust the height position of the tibial insert trial18from the template12. This makes it possible to further reduce the number of components in the configuration of the artificial knee joint replacement operation instrument1for adjusting the height position of the tibial insert trial18. Also, the spacer19is arranged in a partial area of the template12in the inward-outward direction X1of a patient, and in the central portion20of the template12. This makes it possible to shorten the length over which the spacer19comes into contact with the template12and the tibial insert trial18in the inward-outward direction X1. Accordingly, when an operator inserts the spacer19between the template12and the tibial insert trial18, the frictional resistance that the spacer19is subjected to can be further reduced. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, the leading end portion of the spacer19in the inserting direction includes the tapered portions64A and64B, which are formed into tapered shapes. This configuration makes it possible to further reduce the force required to insert the spacer19between the template12and the tibial insert trial18. Accordingly, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, in the inward-outward direction X1, the length of the insertion space57between the template12and the tibial insert trial18is set larger than the length of the spacer19. According to this configuration, the spacer19does not need to be strictly positioned in the inward-outward direction X1relative to the spacer insertion space57when the spacer19is inserted into the insertion space57, for example. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, when the spacer19is inserted between the template12and the tibial insert trial18, the spacer19can be inserted more accurately by being guided by the rails58A and58B.

According to the present embodiment, the tilt restriction mechanism70is provided. According to this configuration, the tibial insert trial18can be restricted from tilting by joining the template12to the tibial insert trial18via the spacer19. This makes it possible to further reduce the amount of labor required by an operator to maintain the orientation of the tibial insert trial18on the template12. As a result, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, the stopper63that defines the position of the spacer19is formed at a front end of the spacer19. Since this stopper63is accommodated in the cutout portion18cof the tibial insert trial18, the stopper63does not become a hindrance around the template12when being accommodated between the template12and the tibial insert trial18. Also, the stopper63can also be used as a portion of the tilt restriction mechanism70, which makes it possible to prevent the shape of the tibial insert trial18in its periphery from becoming complex. This makes it possible to further reduce the amount of labor required to attach the tibial insert trial18to a patient.

According to the present embodiment, the position shift restriction mechanism80is provided. According to this configuration, engagement between the first shift restriction portion81with the second shift restriction portion82can restrict the position of the tibial insert trial18from being shifted in the inward-outward direction X1relative to the template12. This makes it possible to further reduce the amount of labor required by an operator to maintain the orientation of the tibial insert trial18on the template12. As a result, the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

According to the present embodiment, in the inward-outward direction X1, the positions of the fixing pin insertion hole portions30ato30fin the template12differ from the position of the spacer19. According to this configuration, the fixing pins31do not become hindrances when the spacer19is inserted between the template12and the tibial insert trial18in a state in which the template12has been fixed to the tibial100with the fixing pins31. Accordingly, the fixing pins31do not need to be removed from the template12during a height adjustment operation performed using the spacer19, and the amount of labor required to attach the tibial insert trial18to a patient can be further reduced.

Although an embodiment of the present invention has been described thus far, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope recited in the claims. For example, the following modifications are possible.

In the above embodiment, the first direction D1and the second direction D2, which are rotational directions, have been described as examples of the directions in which the first connection mechanism46and the second connection mechanism47are operated. However, this need not be the case. For example, the first direction D1and the second direction D2may alternatively be helical directions, or may be straight directions. Also, a configuration may also be employed in which a lever that passes from a base end to a leading end of the keel punch handle is provided, and the keel punch handle is connected to or disconnected from the inside of the tubular portion of the keel punch by displacing this lever upward or downward.

INDUSTRIAL APPLICABILITY

The present invention is broadly applicable as an artificial knee joint replacement operation instrument used in an operation for replacing a patient's knee joint with an artificial knee joint.

DESCRIPTIONS OF REFERENCE NUMERALS