JPH0332663A - Artificial patella placer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an artificial patella placement device used when installing an artificial patella in an artificial knee replacement surgery.

``Conventional technology'' When a defective knee joint is to be replaced with an artificial patella, the inner surface of the patella is osteotomized to form a joint surface, and the artificial patella is installed there.

In the conventional artificial patella installation device, as shown in FIG. 8, the patella P to be replaced is firmly clamped and fixed by the arms 102 of the scissor-shaped gripper 101, and then the osteotomy is performed using a saw 103. It forms the joint surface with the artificial patella. When the patella P is pinched from the periphery in this way, the joint surface is regulated by the thickness of the arms 102 of the grasper 101, which narrows the range in which the joint surface can be set.
Further, even when changing the joint surface by several ξ mm, there is an inconvenience that the patella P needs to be re-pinched again. In addition,
The reference numeral indicates a ligament that is connected to the patella P, and when cutting the bone to form a joint surface with the artificial patella, the patella P is inverted and grasped with a grasper 101.

Further, after cutting the patella P with a saw 103 to form a joint surface, another person must hold a drilling jig 104 and make a hole with a drill 105 in order to install the artificial patella, as shown in FIG. I can't do the work alone because I can't.

"Problem to be Solved by the Invention" Since the patella P is held by the gripper 101 and then cut with the saw 103 to form a joint surface with the artificial patella, it is necessary to use the arm 102 to hold the patella P at the outer periphery. For this reason, osteotomy cannot be made at any arbitrary position. Furthermore, when drilling a hole in the joint surface of the patella P, another person holds the drilling jig 104 and then drills the hole with the drill 106, so the work requires a drilling depth of 2 Å or more.

``Means for Solving the Problems'' Therefore, the present invention normalizes the compressive force on the patellar joint by eliminating restrictions on height adjustment and enabling accurate installation when determining the position of the joint surface of an artificial patella. In addition, it minimizes the number of people required for the work, improves work efficiency, and allows not only the joint surface osteotomy but also other osteotomies for installing the artificial patella to be performed using the same instrument. The purpose of the present invention is to provide an artificial patella installation device that can be used.

In order to allow osteotomy to be performed at any position along the height of the patella, the inverted patella is not held from the periphery, but from above and below, so that the osteotomy can be performed using a saw from any position on the outer periphery. It is fixed by being sandwiched between a support plate fixed to the body and an elevating member that moves up and down by the rotation of a threaded rod, and the cut guide plate is provided so that it can be slid and fixed to the frame body, so it can be cut accurately at any position. A bone cut can be made.

Further, since the frame body is graduated, it is possible to easily measure the thickness and the cut position of the cut guide plate when the patella is sandwiched between the elevating members on the support plate.

``Operation'' Invert the patella and place it on the support plate, lower the elevating member to firmly fix the upper and lower surfaces, and move the cut guide plate to the desired position for osteotomy based on the support plate. The bone is fixed in place, and the osteotomy is then performed using a saw.

"Embodiment" The present invention will be described in detail based on a specific embodiment shown in the accompanying drawings.

A vertically erected frame 1 has a vertically elongated rectangular guide window hole 2, and a support plate 3 on which an inverted patella P is placed is protruded horizontally from the lower end of the window hole 2, and a screw is inserted into the frame 1. Tighten with screws 4. The support plate 3 for receiving the patella P has a support protrusion 6 on the surface 5.
Protrude and set this as the reference position. Since there is soft tissue in the patella P, the receiving surface 5 should have a gentle bowl-shaped curved surface, and the supporting protrusion 6 should preferably have a rounded tip rather than a sharp tip.

A handle 7 bent diagonally downward from the horizontal is attached to the upper end of the frame 1 by screwing it with a screw 8, so that the setting device can be moved during surgery and it is easy to apply force, but the weight becomes too large. A weight reduction hole 9 is provided to prevent this.

Insert the threaded rod 1 so that it is located in the center of the guide window hole 2 of the frame l.
1 is provided vertically so as to be freely rotatable, and an annular groove 12 is provided at the lower end.
A bottle 13 is driven into the frame 1 so as to fit into the annular groove 12, so that the threaded rod 11 rotates but cannot move in the axial direction. The upper end of the threaded rod 11 has a threaded rod 1
The chuck part 14 is shaped so that 1 can be rotated left and right,
The handle 15 is externally fitted there. handle 15
Since it will get in the way of work except when rotating the threaded rod 11, it should be detachable.

An elevating member 21 is screwed into the guide window hole 2 portion of the threaded rod 11 so as to face the support plate 3, and both sides of the elevating member 21 are guided through the guide window hole 2 so that it can be raised and lowered by rotation of the threaded rod 11.

The elevating member 21 includes a guide member 22 and a pressing member 23. Although the guide member 22 is screwed into the threaded rod 11,
Since it is shaped to fit snugly into the width of the guide window hole 2, it will not rotate together with the rotation of the threaded rod 11, and when the threaded rod 11 is rotated, the guide member 22 will rise or fall. . A rotary shaft 24 is horizontally projected from the guide member 22, and the holding member 23 is rotatably fitted onto the rotary shaft 24, and is fixed by screwing the fixing port 25 at a required inclination.

The pressing surface 30 of the pressing member 23 has a flat shape and is provided with a spike-like protrusion 31 so that the patella P can be firmly fixed. This surface does not have to be a flat surface, but may have a curved surface similar to the shape of the inner surface of the patella P, and instead of the spike-like protrusion 31, it may be provided with curved projections and depressions.

The opposite side of the presser surface 30 of the presser member 23 is formed into an insertion curved surface 32 having a curved surface equivalent to the curved surface of the joint sliding portion.

A guide square hole 33 with a square cross section is provided in the center of the holding member 23, and a guide square hole 33 on the insertion curved surface 32 side is provided.
A chisel guide hole 34 is cut in the vicinity of the corner of 3 to the middle of the guide square hole 33.

The cut guide plate 41 serves as a guide when cutting the joint surface of the patella P and the artificial patella with a bone saw, and can slide on the frame 1 by dovetailing with the frame 1 on its base end side. Its distal end is shaped like an arc plate that surrounds the patella P. A T-shaped bolt 42 is screwed onto the base end so that it can be fixed at any arbitrary position on the frame 1.

A scale 43 is fixed to the side surface of the frame 1, with the point indicating the reference position of the support plate 3 set to zero.

This artificial patella placement device is used as follows.

First, the patella P on which the artificial patella is to be installed is inverted and placed on the support plate 3. The patella P is supported on the support process 6. Next, the chuck part 14 at the upper end of the threaded rod 11
When the handle 15 is fitted and rotated, the guide member 22 of the elevating member 21 is guided by the guide window hole 2 and descends, and abuts against the patella P with the presser surface 30 facing downward. Since the upper surface of the patella P has a complicated shape, the spike-like protrusion 31
After finding the angle of the surface that bites in optimally, tighten the loosened fixing bolt 25.

Next, the cut guide plate 41 is slid on the frame 1 by loosening the T-shaped bolt 42, stopped at a desired position as determined by the scale 43, and is fixed by tightening the T-shaped bolt 42 to cut. The patella P is cut while the bone saw is guided by the guide surface 44 of the guide plate 41.

Next, when making a rectangular attachment hole in the joint surface of the artificial patella, leave the patella P whose joint surface has been cut as it is, turn the handle 15, and press the holding surface of the presser member 23 up to the joint surface. 30 is moved downward and the spike-like protrusion 31 bites into it to fix it. Thereafter, an end mill 46 having a stopper 45 in the middle, as shown in FIG. Next, guide the guide/stretch bar 48 into the guide hole 34 using a chisel 47 shown in FIG. A square hole 49 is cut out and recessed. Then, the state will be as shown in FIG.

Next, when joining the trial or artificial patella to the joint surface of the patella P, loosen the fixing bolts 25 and rotate the holding member 23 180'', tighten the fixing bolts 25 to position the insertion curved surface 32 downward, and tighten the screws. The rod 11 is rotated and lowered to bring the trial or artificial patella into contact with the Ils cap P and apply pressure to join it.

"Effects of the Invention" As described above, the present invention includes sandwiching the upper and lower surfaces of the patella so that an incision can be made from the outer periphery of the patella.
Slide the cut guide plate separately and position it in the specified position.
It becomes possible to freely set the joint surface between the patella and the artificial patella, and it is easy to do so by simply turning a small WL sub-adjustment screw rod on the patella joint surface. - After cutting once, it is also possible to cut several millimeters parallel to each other.

In addition, no matter how many millimeters the actual height of the patella is, it can be instantly read on the scale by moving the cutting guide plate, compared to the conventional method where it could only be determined by pre-operative X-ray measurements. Operators can safely determine the amount of resection based on reliable data.

Furthermore, since there is a scale on the frame, it is easy to decide how many millimeters to cut from the upper surface of the patella, and the work of setting the joint surface can be done extremely freely, accurately, and easily.

Regarding osteotomy for implanting an artificial patella into the patella, the conventional method required a separate jig and another person to hold it during the surgery, but in the present invention, the resected joint surface Press again and keep pushing down to finish the work and secure the patella firmly. Since the holding member also serves as an osteotomy jig, accurate osteotomy can be performed without the need for an extra person.

During this series of operations, the patella is in a dangling state with its muscle band reversed, but the patella is firmly fixed with the instrument, and no extra person is required, which significantly improves the workability of the osteotomy. Further, the drilling work can be done simply by lowering the presser member, making the work continuous and shortening the work time.

When inserting an artificial patella into a patella that has undergone osteotomy, the more precise the process, the smaller the deviation in the insertion angle is required. In the present invention, the presser member can be used as it is as an inserter, and the artificial patella can be accurately press-fitted by taking advantage of precision processing, thereby eliminating failures.

[Brief explanation of drawings]

The drawings show a specific embodiment of the present invention; FIG. 1 is a front view showing the entire structure, FIG. 2 is a right side view of FIG. 1, and FIG.
Fig. 4 is a bottom view of Fig. 1, Fig. 5 is a perspective view of the main parts of Fig. 1, Fig. 6 is a perspective view of the chisel, and Fig. 7 shows the joining surface of the patella with a saw. 8 is a perspective view showing the state in which the patella is grasped with a conventional grasper and cut with a saw; FIG. FIG. 2 is a perspective view showing a state in which a hole is drilled into the patella using the drill. 2... Guide window hole 1... Frame Body P... Patella 3... Support plate 11... Threaded rod 21... Lifting member 41... Cut guide plate

Claims (2)

[Claims] (1) A support plate on which the patella is placed is fixed to the lower end of a frame having a guide window hole, a threaded rod is provided in the frame through the guide window hole so as to be rotatable but cannot move forward or backward, and an elevating member is attached to the support plate. The cut guide plate, which guides the osteotomy of the patella with a saw, can be slid and fixed to the frame body by screwing it onto a threaded rod and guiding it through the guide window hole so that it can be raised and lowered by rotating the threaded rod. Artificial patella placement device (2) An artificial patella in which the elevating member according to claim (1) is constituted by a guide member screwed onto a threaded rod and a presser member rotatably provided on a rotating shaft protruding horizontally from the guide member. installation device