FLEXIBLE EXTERNAL FIXATION FOR CRANIODORSAL COXOFEMORAL LUXATIONS IN DOGS

An external fixator consisting of two Ellis pins connected by a flexib le band was developed and evaluated as a treatment for craniodorsal co xofemoral luxations in dogs. The technique for closed application of t he fixator without injury to the coxofemoral joint or sciatic nerve wa s developed in six dog cadavers. The coxofemoral joints were then surg ically destabilized and the limbs were manipulated through a full rang e of motion to assess the efficacy of the fixator in maintaining joint reduction. The fixator maintained joint reduction and stability after a surgically created craniodorsal luxation except when the femur was externally rotated 90 degrees. A flexible external fixator was then ap plied unilaterally in four healthy dogs. The dogs tolerated the fixato r well and were bearing weight on the limb within 2 days after surgery ; the range of motion was not limited by the fixator. The efficacy of a flexible external fixator in maintaining joint reduction after crani odorsal coxofemoral luxation was then evaluated in eight large dogs. T he right coxofemoral joint in each dog was luxated surgically by remov al of the dorsal joint capsule and transection of the ligament of the head of the femur and deep gluteal muscle. The joint was reduced and t he fixator pins were applied in a closed fashion. In four dogs, a flex ible external band was applied to the pins. Luxation did not reccur in these four dogs. The bands were not applied initially in four control dogs. Luxation occurred in three of the four control dogs within 24 h ours of surgery. The joints that luxated were reduced and the flexible bands applied. Luxation did not recur after the bands were in place. The dogs tolerated the external fixators well, were bearing weight wit hin 2 days of surgery, and walking with only minimal lameness 5 days a fter surgery. Luxation of the coxofemoral joints did not occur during the 2-week period in which the fixators were in place. The joints rema ined stable 1 week after removal of the fixators, at which time the do gs were euthanatized. Necropsy evaluation identified inflammation surr ounding the pins and fibrous thickening of the dorsal joint capsule. T he flexible external fixators were applied closed, maintained reductio n of the coxofemoral joint after replacement of a craniodorsal luxatio n, and allowed weight bearing and limb usage soon after surgery. The f lexible external fixator has several advantages over other methods of treating craniodorsal coxofemoral luxations. Complications noted in th is study included pin tract drainage, pin loosening, and disruption of the flexible bands. (C) Copyright 1994 by The American College of Vet erinary Surgeons