RU2095033C1 - Hip joint endoprosthesis for dogs and method for implanting hip joint endoprosthesis into dog's organism - Google Patents

Abstract

FIELD: veterinary practice. SUBSTANCE: proposed endoprosthesis has been designed by Dr. Samoshkin and Dr. Slessarenko and comprises bowl 1, spherically shaped head piece 2, neck 3 and leg 4 provided with slot-like ports 5. Top part of leg carries supporting platform 6 having opening adapted to receive cotter pin 7. Latter is driven during endoprosthesis implanting operation into supporting platform 6, thereby fixing in place greater trochanter of femur. External side of endoprosthesis bowl 1 has shape of hemisphere provided with concentrically arranged rows of sharpened blade-like projections 9, slits and grooves 12 on its outside. Bowl 1 interior has socket 13 intended to fix head piece 2 with help of stabilizing ring. Endoprosthesis is made of tungsten/titanium and/or cobalt/chrome/molybdenum alloys. Proposed method for implanting said endoprosthesis is practised as follows: first access to dog's hip joint must be provided surgically, followed by resecting caput femoris and by osteotomy of femur at base of greater trochanter. Latter and muscles overlaying it are drawn aside, followed by expanding by drilling-out cotyloid cavity an medullar canal in order to fix in place endoprosthesis bowl and leg by embedding their sharpened elements into bone tissue and by using for this purpose cement and screws. Finally, greater trochanter is fixed on supporting platform 6 with help of cotter pin 7. In conclusion, myoplasty of buttock's group of muscles is practised, and operative wound is sutured for good. EFFECT: new approach in veterinary science. 2 cl, 10 dwg

Description

 The invention relates to veterinary medicine, namely to veterinary surgery and can be used for total hip arthroplasty in dogs.

 The most common indication for total arthroplasty using the Samoshkin-Slesarenko method is dog dysplasia.

 Dysplasia is a multifactorial disease, which is based on hereditary underdevelopment of the elements of the hip joint in embryogenesis and is a combined manifestation of deep, usually irreversible, changes in the cartilage and bone tissues of dystrophic and inflammatory genesis, therefore, restoration of the functional fitness of a dysplastic joint and limb as a whole presents objective difficulties , despite the achievements in the field of reconstructive surgery.

 Other indications for total arthroplasty using the Samoshkin-Slesarenko method are: subcapital, multi-fragmented neck fractures; chronic hip dislocation; Legg-Calve-Perthes disease.

 Known dog hip joint prosthesis made of gelatin and consisting of a three-dimensional cap as the head of the head endoprosthesis. This endoprosthesis resolves over time in the body and does not assume the function of the hip joint.

 The closest in technical essence is the endoprosthesis of the hip joint of dogs Richard, having a removable head and made of high molecular weight polyethylene, and a method for its implantation in the dog's body.

 In its design, the acetabular cup is made separately from the head and legs of the endoprosthesis. The outer part of the cup, in contact with the bottom of the acetabulum, has an oval shape, four spikes are located on it. The top of the cup has the shape of a square with smooth corners. The endoprosthesis leg is whole, tapering downward, curved in the neck region, has no window cuts and supporting platform, and is flat, rectangular in cross section.

 The implantation of an endoprosthesis of the hip joint of Richard is as follows.

 Resection of the femoral head and its removal are performed, and the greater trochanter of the femur does not go astray. Then it is drilled from 3-5 large fixation holes 2 cm deep along the dorsal surface of the acetabulum. Then, with a thin drill with a diameter of 2.7-3.2 mm, multiple holes are drilled around the entire circumference of the cavity. The medullary canal of the femur expands. After that, 20 g of polymethylmethacrylate are mixed with 1 g of cephalotin to obtain a homogeneous mass (cement), which is sequentially inserted into the openings of the acetabulum with a syringe and catheter, filling it to the edges. A similar manipulation is carried out with the femur (cement is introduced into the upper third of the diaphysis). The final stage of the operation is the insertion of the endoprosthesis cup into the acetabulum, and the prosthesis legs into the medullary canal of the femur. After the cement hardens, the endoprosthesis head is set into a cup and the joint capsule is sutured.

 However, the Richard endoprosthesis, as well as the method of its implantation in the dog’s body, has several disadvantages.

 The endoprosthesis Richard is detachable, which does not allow the endoprosthesis replacement of the entire joint simultaneously. The large trochanter of the femur interferes with a thorough revision and preparation of the acetabulum for implantation of the endoprosthesis cup and the exact installation of the endoprosthesis.

 In the postoperative period, as a result of insufficiently strong fixation, a number of complications are noted: dislocation of the endoprosthesis head, lysis of bone tissue in the region of the greater trochanter, as well as in the area of attachment of the cup and leg of the endoprosthesis.

 We have developed a Samoshkin-Slesarenko hip joint endoprosthesis for dogs and a dog hip implant method according to Samoshkin-Slesarenko, devoid of these drawbacks and allowing the total and total prosthetics of pathologically changed hip joints in dogs to be effectively and practically without complications.

 In FIG. 1 shows a hip joint prosthesis for dogs of Samoshkin-Slesarenko design, side view; figure 2 is the same, side view, partially in section; in FIG. 3 the same, view in axonometry; in FIG. 4 section aa in figure 1; figure 5 section BB in figure 1; in FIG. 6 a section BB in FIG.

The hip joint prosthesis for dogs of the Samoshkin-Slesarenko design consists of a cup 1, a ball-shaped head 2, a neck 3 (with a cervical-diaphyseal angle in the prosthesis equal to 145 ^o ) and a leg 4, which has the shape of a tetrahedral pointed bayonet pin with 5 slotted windows . In the upper part of the leg at the place of transition into the neck, a support platform 6 is made with an opening for the cotter pin. Cotter pin 7 during an endoprosthetics operation is hammered into the support platform, fixing a large trochanter of the femur. The endoprosthesis cup 1 on the outside has the shape of a hemisphere, holes 8 are located along the cup edge. On the outer surface of the cup are concentrically arranged rows of pointed shoulder-shaped protrusions 9 with slots 10 between them. In four symmetrically located blade-shaped protrusions, one hole 11 for the screws is made. Between the concentric rows of the shoulder-shaped protrusions, deep grooves are made 12. On the inner side of the cup there is a socket 13 for fastening the head 2, which is fixed in the socket 13 by a stabilizing ring 14. The prosthesis is made of a physiologically acceptable material of tungsten-titanium and / or cobalt-chromium-molybdenum alloy.

 During the movement of the dog, the implanted endoprosthesis, an artificial joint, transfers to the body the pushing efforts of the pelvic limb. The design of the endoprosthesis makes it possible to make movements in all possible planes. A design feature is that the mobility unit in it is removed beyond the bones, which eliminates the possibility of prolonged mechanical microtrauma after surgery. When the animal moves, the muscles are strained, attached to the greater trochanter of the femur, which makes it possible to perform flexion and extension movements in the joint, limb adduction and abduction. At the initial stage of rehabilitation, the head 2 and cup 1 of the endoprosthesis are lubricated due to exudate, and at a later date due to synovia.

 The method of implantation of a hip joint prosthesis in dogs according to Samoshkin-Slesarenko is as follows.

 Patient position on the operating table on a healthy side. Cranio-lateral surgical access with a total length of about 20 cm is made along the outer surface of the thigh, enveloping the major trochanter. Next, the wide fascia of the thigh, the cranial head of the superficial gluteal, middle and deep gluteal, as well as piriform and capsular muscles are dissected. In this case, the limb is slightly supinated, mobilizing the femoral neck, the remaining soft tissues are removed, the line of the osteotomy is outlined and produced in accordance with the intended plan along the intertrochanteric line. The degenerated femoral head, altered capsule, marginal osteophytes are removed. Then, around the proximal hip epiphysis with the help of the Jigley saw, an osteotomy is performed from the greater trochanter to the base of the lesser trochanter. For exposure of the acetabulum, retractors are introduced and deep arthroxerisis is performed using spherical cutters. The acetabulum is carefully drilled, increasing the size of the spherical cutters until drops of blood appear on its walls. It should be noted that the bone structure around the endoprosthesis must be strong, which is important to ensure stable fixation of the cup 1 of the endoprosthesis. The next step in the operation is to drill the medullary canal. For this purpose, a drill is introduced strictly along the longitudinal axis of the thigh, which is a guideline for determining the axis, which makes it possible to ideally install the leg 4 of the endoprosthesis. The final preparation of the medullary canal is performed using a rasp. The required diameter of the cup 1 of the endoprosthesis is determined before the operation by x-ray. During surgery, the caliper determines the size of the acetabulum and select the appropriate endoprosthesis. Cement is injected into the medullary cavity and hammer blows the endoprosthesis leg 4 into the medullary cavity so that the base of the neck 3 of the endoprosthesis coincides with the base of the former femoral neck. It is extremely important when introducing leg 4 of the endoprosthesis to maintain its normal anteversion, focusing on the small trochanter of the femur. In some cases, for better fixation of the leg 4 of the endoprosthesis in the medullary cavity, as well as to stimulate osseointegration through the slot windows 5, it is advisable to fill them and jam the leg 4 with an autograft. For this purpose, a resected head can be used after removing the cartilage coating from its surface.

 After that, several holes are drilled in the acetabulum and cement is poured into it. Without waiting for the cement to harden, with the help of a guide blade, place the endoprosthesis cup 1 into the acetabulum. In this case, it is necessary to carry out traction of the limb along the length and its careful pronation. Then, with light hammer blows, it is extremely important to fully jam the cup 1 of the endoprosthesis with its pointed shoulder-shaped protrusions that must cut firmly into the walls of the acetabulum. For more rigid fixation of the endoprosthesis, screws are used, which are sequentially inserted into the channels pre-drilled into the bones. Screws can be replaced with P-needles. Then, with light strokes, the chisels split in the longitudinal direction the stump of the greater trochanter and the curette form a funnel-shaped cavity for better adaptation of the trochanter with the supporting platform of the endoprosthesis. After that, a hole is drilled in the lower edge of the greater trochanter, a cotter pin is drawn through it, it is pulled to the hole in the supporting platform and hammered with a trauma hammer, thereby fixing the large trochanter with the muscles adjacent to it to the endoprosthesis leg, and make control movements in the hip joint.

 Next, myoplasty of the acetabulum is performed. For this purpose, the capsular muscle is sequentially stitched with the dorsal part of the deep gluteus, and the ventral part of the deep gluteus with the intermediate head of the quadriceps muscle. Then the pear-shaped muscle is sutured at the site of its primary dissection, the ventral part of the middle gluteus is sutured with the intermediate quadriceps head, and the rest of it is sutured at the site of primary dissection. The final stage of myoplasty is stitching of the superficial gluteal muscle at the site of its primary dissection and with the tensor of the broad fascia of the thigh. Next, stitches are placed on the wide fascia of the thigh, subcutaneous tissue and skin. In the postoperative period, animals are given a free dynamic mode.

 The duration of the operation is from 2 to 3 hours. It is regulated by the volume of the joint, the degree of damage to the articular surfaces and adjacent muscles.

 Example 1. Dog breed Laika, male, registration N 451-96, age 1.6 years, diagnosis: induced dysplasia of the left hip joint, chronic dislocation of the femoral head.

 Collie dog, male gender, registration N 454-96, age 1.6 years, diagnosis: induced dysplasia of the right hip joint, chronic dislocation of the femoral head.

 Outbred dog, male, registration N 448-96, age 1 year, diagnosis: induced dysplasia of the left hip joint, chronic dislocation of the femoral head.

 The listed animals underwent hip implant surgery according to Samoshkin-Slesarenko and implants of the hip joints of the Samoshkin-Slesarenko design were implanted.

 All operated animals satisfactorily underwent hip implant implantation surgery. Awakening from anesthesia usually occurred 2-3 hours after the end of surgery. Over the next day, the animals refused to accept writing, being in a state of adynamia. An improvement in the general condition was recorded on the third day, patients began to proceed slightly to the operated limb, gradually increasing the load on it. In all cases, suture healing was carried out according to the type of primary tension. During the month of follow-up, marked lameness of the type of leaning limb of varying severity was noted, the general condition in all operated animals was satisfactory. In all cases, cosmetic defects and neurological disorders were absent, muscular hypotrophy was observed, anatomical continuity of soft tissues, defects of bone marrow and postoperative scars was noted, inflammatory reactions from the skin, subcutaneous tissue and bone tissue were not observed.

 The observation results are confirmed by x-ray data (see Fig. 7 and Fig. 8).

 In FIG. Figure 7 shows an x-ray of the area of the hip joint of a dog with an implanted endoprosthesis of the Samoshkin-Slesarenko design. Fixation of the endoprosthesis cup with cement and screws; in FIG. 8 x-ray of the area of the hip joint of a dog with an implanted endoprosthesis of the Samoshkin-Slesarenko design. Fixation of the endoprosthesis cup with cement and P-needles.

 The functional state of the joints of the distal parts of the operated limb was within the physiological norm. The full range of movements in all possible planes was restored in the implanted joints; there were no vasogenic disturbances. Complete restoration of functional fitness of the operated joints was noted, according to statistical analysis, after 1-2 months after total arthroplasty.

 The described operative access is less traumatic and more sparing, and at the same time allows for a more thorough revision of the acetabulum and the exact installation of the endoprosthesis. Simultaneous fixation of the endoprosthesis with cement and screws, as well as myoplasty of the nadacetular region, allows the animal to proceed to the operated limb 3-4 days after the operation. The functional fitness of the joint and limb as a whole is restored 1-1.5 months earlier than after fixing only with cement or with screws alone.

 Morphological studies of bone tissue adjacent to the implant, carried out 1 month after endoprosthetics, revealed differences in the microstructure of bone tissue after fixing the endoprosthesis cup with screws (see figure 9) and after simultaneously fixing the endoprosthesis cup with cement and screws (see figure 10) .

 In FIG. 9 shows the microstructure of adjacent tissue during fixation of the endoprosthesis cup with screws. Foci of chondroid proliferate are visible, indicating micro-mobility of the endoprosthesis. (Hematoxylin and eosin, vol. 10, approx. 8).

 In FIG. 10 shows the microstructure of adjacent bone tissue during fixation of the endoprosthesis cup with cement and wood screws. A coarse-fibered bone tissue is visible with the initial stage of bone structure remodeling, which indicates the stability of the implant-endoprosthesis. (Hematoxylin and eosin, vol. 10, approx. 8).

 Thus, the simultaneous fixation of the endoprosthesis with cement and screws, as well as myoplasty of the nadacetular region, creates a zone of mechanical rest of the implant. The processes of osseointegration through the slot windows proceed as the primary fusion with the formation of bone directly, bypassing the stage of chondroid proliferate, which ultimately significantly reduces the rehabilitation period and contributes to a more stable fixation of the endoprosthesis.

Claims (2)

 1. An endoprosthesis of a hip joint for dogs, including a head and a leg connected by a neck, and a cup made of physiologically acceptable material, characterized in that the head has a spherical shape, the endoprosthesis leg has the shape of a tetrahedral pointed bayonet pin with slotted windows in the upper part legs at the point of transition into the neck, a support platform with a hole for the cotter pin is made, and the cup is hemispherical on the outside, holes are located along the edge of the cup, concentric rows of sharpened spatula-shaped protrusions with slots between them, holes for screws are made in four symmetrically arranged spatula-shaped protrusions, deep grooves are made between the concentric rows of spatula-shaped protrusions, a socket for fastening the head is made on the inside of the cup, the head is fixed in the socket with a stabilizing ring, and in as a physiologically acceptable material, the prosthesis is made of a tungsten-titanium and / or cobalt-chromium-molybdenum alloy.  2. A method for implanting a hip joint implant in dogs, including performing a cranio-lateral incision of the skin and subcutaneous tissue, dissecting the gluteal muscle group, opening the joint capsule, resecting the femoral head, expanding the medullary canal, fixing the cup of the endoprosthesis in the acetabulum and the legs of the endoprosthesis on cement in the medullary canal, as well as suturing of the joint capsule, gluteal muscle group, subcutaneous tissue and skin, characterized in that after resection of the femoral head an additional but the osteotomy of the femur in a straight line connecting the lower edge of the large and the middle of the small trochanter, take the large trochanter with muscles to the side, drill the bottom and wall of the acetabulum, fix the cup and legs of the endoprosthesis by cutting their pointed elements into the walls of the acetabulum and medullary canal, then fix the cup of the endoprosthesis in the acetabulum with screws and a large trochanter on the supporting site of the endoprosthesis with a cotter pin, and suturing of the gluteal muscle group is carried out in the following order: the capsular muscle with the dorsal part of the deep gluteus and the ventral part of the deep gluteus with the intermediate head of the quadriceps muscle are sutured, the pear-shaped muscle is stitched at the site of its primary dissection, the ventral part of the middle gluteus with the intermediate head of the quadriceps, the rest of the middle gluteus at the site of its primary dissection, and the surface the gluteus muscle at the site of its primary dissection and with a tensor of the wide fascia of the thigh and sutures on the wide fascia of the thigh.

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