Dogs with CHD are born with normal hips that subsequently undergo varying degrees of subluxation of the coxofemoral joint. Although the etiology of CHD is multifactorial, the pathogenesis or stages of change within the affected coxofemoral joint(s) are similar regardless of cause. With the onset of the disease, there are progressive structural changes including joint laxity and femoral head subluxation; swelling, stretching, fraying, and eventual rupture of the teres ligament; a shallow, flattened acetabulum, deformity of the head; erosion of articular cartilage, eburnation of subchondral bone, DJD; and periarticular osteophyte formation.