CASE REPORT

and anchoring each piece into place with screws' or Kirschner wires2.

Surgical Repair of a Comminuted Distal Femoral Fracture in a Dog

History A female Labrador retriever dog, 13 weeks of age was presented to the Small Animal Clinic. The owner reported that she jumped out the side window of a pick-up truck three hours earlier and since then, would not bear any weight on her left hind leg. She exhibited pain and discomfort.

K.R. PRESNELL*

Summary This case illustrates that good results may be achieved with fractured femur that was severely comminuted (i.e. a "Humpty Dumpty" fracture). The blood supply at the fracture site must be carefully preserved. The bony architecture must be reestablished with perfect reduction of the articular surfaces, preferably with interfragmentary compression between the bone fragments. These fragments are held in place with screws and Kirschner wires. Some of the screws and pins were left in place as the trauma incurred to retrieve them would have done more harm than good due to bony overgrowth.

Clinical Findings The dog's general systemic condition was stable. The leg was swollen at the left stifle and the dog was carrying the leg. Palpation of the area revealed crepitation and an abnormal size and shape of the distal femur. Examination of the radiographs of the area indicated that the distal third of the left femur was fractured into numerous fragments. Several fracture lines appeared to cross the epiphyseal plate and the distal articular cartilage of the femur (Figures I and 2).

Re'sume Reparation chirurgicale d'une fracture comminutive de la partie distale du femur, chez un chien Ce cas illustre la possibilite de reduire une fracture comminutive du type: "Humpty Dumpty". II faut preserver soigneusement la vascularisation, au site de la fracture, et retablir l'architecture osseuse en reparant parfaitement les surfaces articulaires, de preference par une compression entre les fragments osseux qu'on fixe a leur place au moyen de vis et de fils de Kirschner. Dans ce cas-ci, on evita d'enlever certains de ces fils et vis, parce qu'on aurait ainsi provoque plus de tort que de bien, etant donne qu'ils etaient recouverts par le cal osseux.

Introduction Comminuted fractures which extend through articular cartilage present a challenge to the orthopedic surgeon. They are difficult to repair and the prognosis is usually poor. A shattered distal canine femur with an exploded joint surface was rebuilt with meticulous attention to reestablishing the continuity of the articular surface

FIGURE 1. Lateral view of the comminuted fracture of the femur before surgery.

Surgery The client was advised of the possibility of an altered or arrested growth pattern of the femur as a result of injury to the distal femoral growth plate.

*Diplomate, American College of Veterinary Surgeons, Department of Veterinary Clinical Studies, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N OWO. '2.7 mm cortical screw, Synthes Canada Ltd., Mississauga, Ontario. 2Kirschner wire, Synthes Canada Ltd., Mississauga, Ontario.

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Can. vet. J. 20: 196-198 (July 1979)

FIGURE 2. Craniocaudal view of the femur before surgery.

FIGURE 3. View of the femur after completion of surgical repair.

The dog was prepared for surgical repair 24 hours later. Anesthesia was induced with sodium thiamylal3 after atropine sulfate4 and meperidine hydrochloride5 premedication. The patient was maintained with halothane anesthesia and oxygen. After preparation of the area, it was draped with a sterile adhesive plastic drape6 and a bilateral approach was made to the distal femur, including the stifle joint (1). Exposure revealed that the femoral fractures were much more extensive than shown radiographically: the trochlear groove area was displaced cranially, the condyles separated, each condyle was split into several pieces, the epiphyseal growth plate separated and a wedge was broken off the medial aspect of the femur. Initially, attempts were made to reform the distal articular surface by interfragmentary screw fixation of larger pieces of the medial and lateral condyles. The other pieces of the condyles were fitted into place and held with Kirschner wires and then other fragments of adequate size were lag-screwed into place using 2.7 mm cortical screws. The trochlear flap on the cranial aspect was replaced and anchored with a screw from the lateral trochlear ridge and a Kirschner wire from the medial trochlear ridge. This reformed distal fragment was then attached

to the femoral diaphysis with two cross Kirschner wires. The large fragment on the medial shaft was then replaced and was held with two small Kirschner wires. A small defect remained in the caudal aspect of the femur just proximal to the intracondylar fossa (Figures 3 and 4). The cruciate ligaments and menisci were intact. The joint was flushed with Ringer's solution which included one million units of sodium crystalline penicillin in the final flush. The joint capsule was closed with 0 polyglycolic acid material7 in a simple interrupted suture pattern and the deep fascia was closed in a similar manner. The subcutaneous tissues were opposed with 000 polyglycolic acid suture in a simple interrupted pattern and the skin was closed over this with 000 polyethylene8 in an interrupted pattern.

Postoperative Care Postoperative care involved a light bandage for three days to minimize swelling, and cage rest for ten days. The sutures were removed in 14 days by which time the dog had begun to bear some weight on the leg. Examination of the radiographs revealed the fragments were still in place and early signs were compatible with healing. At five weeks, the dog was using the leg for full weight support

3Surital, Parke Davis & Co., Brockville, Ontario. 4Atropine Sulfate, Glaxo Laboratories, Toronto, Ontario. 5Demerol, Winthrop Laboratories, Aurora, Ontario. 6Steri-Drape, 1025 3-M Company, St. Paul, Minnesota. 7Dexon, Davis & Geck, Cyanamid of Canada, Montreal, Quebec. 8Linear Polyethylene, Davis & Geck, Cyanamid of Canada, Montreal, Quebec.

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FIGURE 4. Craniocaudal view of the femur after surgical repair.

FIGURE 5. A lateral radiograph of the femur 12 months after the surgical repair.

and showed minimal clinical evidence of lameness. At ten weeks, healing was judged adequate radiographically so the dog was anesthetized, the joint reopened for removal of the screw and two Kirschner wires which were holding the trochlear flap in place. The rest of the screws and Kirschner wires were left in place due to the extensive surgery necessary to remove them. The dog was reexamined 12 months later and examination of the radiographs revealed the bone to be well remodelled (Figures 5 and 6). Discussion One year later this dog is showing no clinical signs of lameness and tolerates exercise very well, although the left femur is a little shorter than the right one. The owners are using her for field trial work. The prognosis in such a case is always poor. With meticulous attention to reforming articular surfaces by rebuilding the bone anatomically and by providing stability, good results may be achieved. The main complications are growth changes or arrest due to ischemic or trauma to the zone of cellular division of the growth plate which results in a shorter leg or an angulation of the limb distal to the growth plate. Secondary osteoarthritis of the involved joint may result in pain and disuse. The age of the dog, the high ratio of cancellous to cortical bone at the fracture site, successful reestablishment of the articular surface, adequate stability and the fact that the dog, unlike man, can compensate for minimal changes in leg length and the time from injury to surgical repair are all important factors in the success of this case.

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FIGURE 6.

Craniocaudal radiograph of the femur 12

months after surgical repair. As we learn more about the reactions of body tissues to trauma and improve our methods of

fracture reduction, immobilization and stabilization, the success for these cases will improve.

References 1. PIERMATTEI. D.L. and R.G. GREELEY. An Atlas of Surgical Approaches to the Bones of the Dog and Cat.

p. 106. Philadelphia, London and Toronto: W.B. Saunders Company. 1966.

Surgical repair of a comminuted distal femoral fracture in a dog.

CASE REPORT and anchoring each piece into place with screws' or Kirschner wires2. Surgical Repair of a Comminuted Distal Femoral Fracture in a Dog...
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