JP4067813B2 - Marking aid for total knee arthroplasty - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an auxiliary tool used for marking a resection surface at a distal end of a femur in knee replacement.
[0002]
[Prior art]
Various types of artificial knee joints including a thigh-side element (femoral component) and a tibia-side element (tibia base plate) are known. Among them, the femoral component is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-313845. For attachment of this type of femoral component to the femur, the distal end of the femur must be cut into an appropriate shape. That is, as a first stage of cutting, the distal end of the femur is cut flat and a cutting guide is attached to the flat cut surface. Then, by using this cutting guide, excision of the medial and lateral condyles at the distal end of the femur is performed. In order to accurately perform this resection, a caliper-like marking aid is mounted on the resection surface at the distal end of the femur, and a reference line is marked on the resection surface with a marking pen using ink such as methylene blue. A guide for cutting work is attached to the reference line.
[0003]
[Problems to be solved by the invention]
The reference line drawn on the resection surface of the distal end of the femur is located on the vertical extension line of the center point of the accessory ligament attachment located on both sides of the medial and lateral condyles of the femur. However, although the accessory ligament adhering portion is considerably separated from the resection surface of the distal end of the femur, there has been a problem that an error is likely to occur because the reference line has been drawn with a register in the past.
[0004]
The present invention has been made in view of the above-described problems of the prior art, and it is an object of the present invention to provide a marking aid that can accurately perform the marking of the reference line on the resection surface of the distal end of the femur.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided an auxiliary tool for marking the resection surface at the distal end of the femur in artificial knee joint replacement, and the pair of support arms movable in parallel with each other, and the pair of arms. intersection of the engaging member provided so as to face the opposing surface of the support arm, a first locking means for locking the translation of the pair of support arms at a desired interval, and the flat ascending movement of the support arm Marking for artificial knee joint replacement, comprising: a marking guide bar that moves in a moving direction; and a second locking means that locks the movement of the marking guide bar in the intersecting direction at a desired position. Auxiliary tools are provided.
[0006]
The action and effect of the invention of claim 1 will be described. The pair of support arms are moved in the approaching direction with the inner and outer condyles of the thigh sandwiched between them, and the opposing engagement members of the pair of support plates are The reference point is applied to the center point of the accessory ligament attachment portion at the condyles inside and outside the femur, and the relative positions of the pair of support arms are locked by the first locking means. In this locked state, the pair of support arms are appropriately rotated about the engaging portion as a fulcrum, and the marking guide on the pair of support arms is positioned on the vertical extension line of the center point of the accessory ligament attachment portion. In this state, the marking guide is moved toward the excision surface, the marking guide is brought into contact with the excision surface, and the marking guide is brought into contact with the excision surface, and the marking guide with respect to the support arm is held by the second locking means. The position is locked. Thereafter, a reference line is drawn on the cut surface by a marking pen using a marking guide as a ruler and using an ink such as methylene blue. Therefore, by using the marking aid of the present invention, the reference line can be drawn reliably and easily on the extension of the reference point. If necessary, an arbitrary parallel line can be freely drawn by slightly rotating the support arm.
[0007]
According to a second aspect of the present invention, in the first aspect of the present invention, one support arm of the pair of support arms has a protruding portion and is substantially L-shaped, and the one support arm There is provided a marking assisting device for artificial knee joint replacement, wherein the overhanging portion of the arm and the other supporting arm are slidable with respect to each other, thereby obtaining the parallel movement between the supporting arms.
[0008]
The operation and effect of the second aspect of the invention will be described. The relative movement of the pair of support arms can be smoothly performed by the slide structure, and the operation of the marking auxiliary tool becomes easy.
[0009]
According to the invention described in claim 3, in the invention described in claim 2, the one support arm and the marking guide bar are slidable with respect to each other, whereby the movement of the marking guide bar in the intersecting direction is performed. A marking assisting device for artificial knee joint replacement is provided.
[0010]
The operation and effect of the invention of claim 3 will be described. The marking guide bar can be smoothly moved by the slide structure, and a high-precision reference line can be drawn reliably and easily, thereby eliminating the marking mistake. be able to.
[0011]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the first or second locking means is a screw type knob. A marking aid for joint replacement is provided.
[0012]
The operation and effect of the invention of claim 4 will be described. The support arm or the marking guide bar can be easily and reliably locked by using the first or second lock means as a screw type knob.
[0013]
According to the invention described in claim 5, in the invention described in any one of claims 1 to 4, the engaging member has a sharp tip fixed to each of the opposing surfaces of a pair of support arms. There is provided a marking assisting device for artificial knee joint replacement, which is characterized by having a locking pin.
[0014]
The action and effect of the invention of claim 5 will be described. The engaging member is a locking pin having a sharp tip fixed to each of the opposing surfaces of the pair of support arms. A sharp pin at the tip of the femoral condyle punctures the adjunct ligament attachment on both sides to reach the bone surface, and the marking guide bar is accurately positioned at the extension of the center point of the adjunct ligament attachment Since there is no fear of displacement, more reliable marking can be performed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, the assisting tool for marking of the resection surface at the distal end of the femur in artificial knee joint replacement includes a pair of support arms 10 and 12 that can be translated relative to each other. The first support arm 10 has an inverted L shape, and includes an overhang portion 10-1 bent at a right angle toward the second support arm 12. The overhang portion 10-1 includes a guide slot 14 extending in the longitudinal direction, and the slide portion 12-1 (see FIG. 5) at the upper end of the second support arm 12 is fitted into the guide slot 14, and as a result. The second support arm 12 is slidable as indicated by an arrow a in FIG. 1 while maintaining a parallel relationship between the second support arm 12 and the first support arm 10. The upper end of the second support arm 12 protruding from the guide slot 14 forms a screw portion 12-2 (see FIG. 5), and the lock knob 16 is screwed into the screw portion 12-2. Therefore, when the lock knob 16 is fastened in a state where the support arms 10 and 12 are at an expected interval, the lock knob 16 and the overhanging portion 12-1 are tightly fastened on the opposing surface, and the support arm 10 , 12 are fastened so that there is no relative movement between them.
[0016]
In FIG. 1, reference numeral 18 denotes a marking guide bar, which has a cross-sectional shape with its lower end pointed like a knife edge as shown in FIG. As shown in FIG. 1, the first support arm 10 has a guide slot 19 extending in the longitudinal direction (vertical direction), while the second support arm 12 also extends in the longitudinal direction in parallel with the guide slot 19. A guide slot 20 is provided, and one end of the marking guide bar 18 extends freely through the guide 20. The marking guide bar 18 has a connecting portion 18-1 and a slide portion 18-2 (see FIG. 2) extending from the connecting portion 18-1 at the other end, and this slide portion 18-2 is the first support arm 10. The guide slot 19 is fitted. As a result, the marking guide bar 18 is slidable up and down as shown by the arrow b in FIG. As shown in FIG. 2, the marking guide bar 18 has an end protruding from the guide slot 19 forming a screw portion 18-3, and a lock knob 22 is screwed into the screw portion 18-3. Therefore, by fastening the lock knob 22 in a state where the marking guide bar 18 is at the desired height position, the lock knob 22 and the support arm 10 are tightly fastened on the opposing surface, and the marking guide bar 18 is The support arm 10 is fastened so as not to move relative to each other.
[0017]
In FIG. 1, the supporting arms 10 and 12 are provided with locking pins 24 and 26 as engaging members of the present invention on opposing surfaces. The locking pins 24 and 26 have a sharp tip, and as will be described later, this tip can be used to fix to the adjunct ligament attachment portion as a reference point in artificial knee joint replacement. it can.
[0018]
Referring to the operation of the marking aid of the present invention, the femur A schematically shown in FIG. 1 is shown with the condyle at the distal end thereof facing up. The distal end of the femur A has already been excised as a flat surface B. An opening C in the flat surface B indicates a hole formed in the femoral load axis direction for mounting a cutting guide for excision of the flat surface B. D is an accessory ligament, which exists on both sides of the medial side and the lateral side (only one side is shown in FIG. 1), and is attached to the condyles of the femur A in a semicircular shape at the site D ′. The marking aid of the present invention is useful for drawing a reference line on a flat surface in a vertical extension of the center point of the collateral ligament adhesion portion D ′ on both sides as a reference point.
[0019]
Next, the reference line marking procedure by the marking aid will be described. FIG. 2 shows the first stage (A) of the operation of the marking device, and the support arms 10 and 12 with the knobs 16 and 22 loosened together. The femur A is positioned between them, and the tips of the locking pins 24 and 26 on the opposing surfaces of the support arms 10 and 12 are made to face the attachment portions D ′ of the inner and outer collateral ligaments D.
[0020]
Next, as shown in the second stage (b) of FIG. 3, the support arms 10 and 12 are slid in the opposite direction (the direction of the arrow a1), and the locking pins 24 and 26 are moved to the corresponding side ligament attachment portion D ′. The lock knob 16 and the opposite surface of the overhanging portion 10-1 are tightly fastened by tightening the lock knob 16 to the screw portion 12-2, The support arms 10 and 12 are fastened (locked) to each other.
[0021]
Since the locking pins 24 and 26 are punctured so as to bite into the bone surface at the central portion of the respective accessory ligament attachment portions D ′, the support arms 10 and 12 are supported so as to be rotatable around the puncture portion. . That is, it can be rotated from the inclined state shown in FIG. 5A to the upright state shown in FIG. In the upright state shown in (b), the marking guide bar 18 is positioned vertically above the locking pins 24 and 26.
[0022]
The marking guide bar 18 is moved downward as shown by the arrow b1 from the state shown in FIG. 3 (b). FIG. 4 shows the third stage (c) of the operation of the marking aid. It is in contact with the flat excision surface B at the distal end of the bone. Then, by fastening the lock knob 22 to the screw portion 18-3, the lock knob 22 and the support arm 10 are tightly fastened on the opposing surface, and the support arm 10 and the marking guide bar 18 are fastened (locked) to each other. Is done. This state corresponds to (c) in FIG. 5, and the marking guide bar 18 is located on the vertical extension line of the central portion of the accessory ligament adhesion portion D ′ which is the reference point. Then, the tip of the marking pen 30 is applied to the lower edge 18 'of the marking guide bar 18 with respect to the flat excision surface B at the distal end of the femur, and the marking guide bar 18 is marked as a ruler, thereby attaching the collateral ligament as a reference point. The reference line can be accurately marked on the flat excision surface B of the distal end of the femur on the vertical extension line of the center portion of the portion D ′. The reference line drawn in this way is indicated by a one-dot chain line L in FIG.
[0023]
In some cases, it is necessary to mark the line parallel to the already drawn reference line for fine adjustment. In this case, loosen the lock knob 22 and raise the marking guide bar 18 slightly, focusing on the locking pins 24 and 26. The line parallel to the reference line L can be easily drawn by slightly turning, lowering the marking guide bar 18 so as to contact the cut surface B, locking it again, and marking along the marking guide bar 18.
[0024]
In the embodiment of the present invention, since the tips of the locking pins 24 and 26 are punctured and supported at the center of the accessory ligament attachment portion D ′ as the reference point, there is no deviation of the reference point, and the marking auxiliary tool rotates. This enables the marking guide bar 18 to be accurately positioned vertically above the reference point, so that the reference line on the resection surface at the distal end of the femur and the line parallel thereto can be marked regardless of simple operation. It is possible to always perform accurately and conveniently.
[Brief description of the drawings]
FIG. 1 shows a perspective view of a marking aid of the present invention.
FIG. 2 is a front view of the marking aid of the present invention and shows the first stage (A) of attachment to the distal end of the femur.
FIG. 3 is a front view of the marking aid of the present invention and shows a second stage (b) of attachment to the distal end of the femur.
FIG. 4 is a front view of the marking aid of the present invention, and shows a third stage (c) of attachment to the distal end of the femur.
FIG. 5 is a side view of the marking assisting tool of the present invention, and shows the stages (a), (b), and (c) of attaching the marking assisting tool.
[Explanation of symbols]
10: First support arm
10-1 ... Overhang 12 ... Second support arm 14 ... Guide slot 16 ... Lock knob 18 ... Marking guide bar
19, 20 ... Guide slot 22 ... Lock knob
24, 26 ... locking pin A ... femur B ... excision surface C ... opening (mounting hole for alignment guide)
D ... accessory ligament D '... accessory ligament adhesion part

Claims (5)

An auxiliary tool for marking a resection surface at the distal end of the femur in total knee arthroplasty, and a pair of support arms that can move in parallel with each other, and facing the opposing surfaces of the pair of support arms an engaging member provided, a first locking means for locking the translation of the pair of support arms at the desired spacing, a marking guide bar that moves in a direction intersecting the flat ascending movement of the support arm, the A marking assisting tool for artificial knee joint replacement, comprising: a second locking means for locking the movement of the marking guide bar in the intersecting direction at a desired position.   The invention according to claim 1, wherein one support arm of the pair of support arms has an overhang portion and is substantially L-shaped, and the overhang portion of one support arm and the other support arm Slidable with respect to each other, whereby the translational movement between the supporting arms is obtained.   3. The artificial knee joint replacement according to claim 2, wherein the one supporting arm and the marking guide bar are slidable with respect to each other, whereby the movement of the marking guide bar in the intersecting direction is obtained. Surgical marking aid.   4. The marking assisting device for artificial knee joint replacement according to claim 1, wherein the first or second locking means is a screw type knob. 5.   The invention according to any one of claims 1 to 4, wherein the engaging member is a locking pin having a sharp tip fixed to each of the opposing surfaces of a pair of support arms. Marking aid for artificial knee joint replacement.

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