Treating Legg-Perthes Disease: A Surgeon’s Advice
Zee Mahmood, a veterinary technician in Reading, PA, contributed to this article.
Legg-Perthes disease is a condition that affects the hip of the dog at the ball-in-socket joint where the femur (thigh bone) meets the pelvis. Also known as Legg-Calvé-Perthes disease, this disorder causes the femoral head (the ball of the hip joint) to spontaneously disintegrate, ultimately collapsing the joint and resulting in a very painful and dysfunctional condition.
Because of the pain involved, dogs may become irritable and “not themselves.” Progressive limping may occur, with a dog bearing no weight on the affected limb within roughly two months. Atrophy, or loss of muscle mass, is visible in the thigh.
Is your dog at risk for Legg-Perthes disease?
Legg-Perthes disease is found in puppies of miniature, toy, and small dog breeds such as small terriers (e.g. Yorkshire), Miniature Pinschers and Toy Poodles. There is also evidence of hereditary predisposition, so breeding of affected dogs is discouraged. Males and females alike can be affected, and most patients are 5-8 months old.
The cause of Legg-Perthes disease
While the precise cause of Legg-Perthes disease is unknown, evidence suggests that the disease occurs when blood supply to the head of the femur is inadequate, causing the bone in that area to die. This results in weakened bone, followed by fracture and collapse of the femoral head.
Other hip conditions can cause signs that can appear similar to Legg-Perthes disease, such as fractures, dislocations, or hip dysplasia. Another disorder that commonly affects small breed dogs is a dislocated knee cap (medial luxating patella or MPL).
Diagnosing Legg-Perthes disease
When examining a dog that is suspected to have Legg-Perthes disease, your veterinarian or surgeon will perform several orthopedic tests. Among these, extending the hind leg backwards will invariably make a dog with the disease react painfully.
Since other hip conditions can make a dog react the same way, the next step is to take hip X-rays. This is ideally done under sedation to get good quality pictures and avoid pain. Collapse and fracturing of the hip can be detected on X-rays.