Introduction
Hip dysplasia is common disorder in dogs that involves abnormal development and subsequent degeneration of the coxofemoral (hip) joint. It is thought that the immature hip joints of affected dogs have a genetic predisposition to subluxate (partially dislocate), causing abnormal forces across the hips, irregularly shaped bones, damaged articular cartilage, microfractures and, in severe cases, osteoarthritis. It is important for owners to recognize the clinical signs of hip dysplasia so that effective treatment options can be pursued as early in the course of the disease as possible. This can be difficult, however, because the signs of hip dysplasia often mimic those of other degenerative disorders.
Symptoms of Hip Dysplasia in Dogs
Hip dysplasia is one of the most common skeletal disorders seen clinically in dogs. Large and giant-breed dogs have the highest incidence of hip dysplasia, including St. Bernhards, German shepherds, Labrador retrievers, Golden retrievers and Rottweilers. Small breeds can also be affected but are less likely to exhibit clinical signs of the disease. Both sexes are affected equally, and clinical signs tend to show up early, usually between 4 and 12 months of age, although signs of osteoarthritis can first present in more mature animals.
The main effect of hip dysplasia is rear leg lameness characterized by a “bunny-hopping” or swaying gait, pain or weakness in one or both hind legs, difficulty rising, exercise intolerance, reluctance to run or jump (into cars, onto furniture, etc), and sometimes an audible “clicking” sound coming from the hips when rising or walking (called “crepitus”). Other signs include a narrow hind-end stance, poor pelvic limb conformation and musculature, hypertrophy (enlargement) of the shoulder muscles and sometimes an arched appearance of the spine caused by the shifting of weight to the forelimbs. These signs may be intermittent or persistent and tend to worsen after exercise. Affected dogs may seem fine most of the time, but be stiff in the morning or after a nap. Obesity or rapid weight gain can exacerbate the lameness and pain associated with this disease.
If left untreated, hip dysplasia will progress and the symptoms will become more obvious to owners. Owners should be especially aware of signs in young, rapidly-growing large and giant breed dogs in the first year of their life, and in aging dogs. Medical and surgical treatments are available that can greatly reduce the discomfort caused by hip dysplasia, allowing affected dogs to remain active lead normal lives.