COMPLICATIONS OF ARTICULAR LAG SCREW FIXATION OF FEMORAL CAPITAL EPIPHYSEAL SEPARATIONS

Four femoral capital epiphyseal separations in three immature dogs were repaired using an articular lag screw procedure. Two millimetre cortical screws were inserted from the articular surface across the fracture site in lag fashion. The screw heads were countersunk below the surface of the articular cartilage to prevent abrasion of the apposing articular surface. Marked osteolysis of the femoral neck was noted between four and eight weeks postoperatively in all cases, and excision of the femoral head and neck was carried out in two cases at six and eight weeks postoperatively. It is believed that the surgery failed because of iatrogenic vascular insult and the development of coxofemoral instability.