Bilateral dislocation of the hip joint and associated pathological changes in the ossa coxae and femora of a European roe deer (Capreolus capreolus)

Abstract

We describe a bilateral craniodorsal dislocation of the hip joint in a free-ranging young roe buck and the associated pathological changes in the ossa coxae and femora of the animal. The highly symmetrical dislocation, which is considered to have developed secondary to hip dysplasia, caused the formation of two false acetabula that each consist of several, partially fused bone portions. The femora exhibit symmetrical outgrowths that extend from the greater trochanter along the intertrochanteric crest to the lesser trochanter. Formation of these outgrowths is attributed to abnormal traction at muscle attachment sites due to the displacement of the femora. On radiographic examination, both femora show signs of avascular necrosis in their head regions and of fatty marrow necrosis in their shafts, which is attributed to the damage of the arterial blood supply of the femora that was associated with the dislocation. The fact that, according to the hunter who shot the buck, the animal's locomotion was inconspicuous suggests that the false hip joints functioned quite well, thereby demonstrating a remarkable capacity of the musculoskeletal system for functional recovery.