Legg-Calve-Perthes Disease in Dogs

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Legg-Calve-Perthes Disease is a debilitating condition in dogs that leads to loss of function of one or both rear legs. It is also called avascular or aseptic necrosis of the femoral head, and it is a condition of the hip joint.

The hip is a ball-and-socket joint. The ball part of the joint is formed by the head and neck of the femur, which is the large thigh bone. The socket is part of the pelvis.

In Legg-Calve-Perthes disease, an interruption of the blood supply to the head and neck of the femur causes the bone there to die. Eventually, the blood supply returns to normal, and the bone remodels itself. However, while it is in the diseased state and the animal bears weight on it, the head of the femur becomes flattened. Therefore, when the bone remodels to that new shape, the joint becomes deformed. Severe arthritis then develops quickly. The hip is extremely painful for the dog during the initial low blood supply phase and chronically sore after the remodeling phase.

Presentation and Signs of Legg-Calve-Perthes Disease in Dogs

• Irritability is often the first sign that there is a problem, but it can be quite vague and difficult to determine a cause.
• Licking and chewing at the hip area may be seen early in the disease process, and this allows you to narrow the problem down to the hip and report it to your veterinarian.
• Pain from Legg-Calve-Perthes disease as it progresses may cause your dog to cry out, especially when stretching a rear leg or rising from a lying down position.
• Lameness will eventually occur as the dog has difficulty bearing weight on the affected leg. He will limp considerably or hold the leg up entirely.
• As time goes on, your dog will experience loss of muscle mass over the affected hip as the muscles become smaller from disuse.
• Ultimately, the affected leg will appear shorter than the other one.

Causes of Legg-Calve-Perthes Disease in Dogs

Legg-Calve-Perthes disease in dogs is caused by an interruption in the blood supply to the head and neck of the femur. The exact mechanism for this disturbance is not understood. Most cases have a genetic basis, but Legg-Calve-Perthes disease can also be caused by trauma to the hip.

Breeds, Gender, and Age Most Commonly Affected by Legg-Calve-Perthes Disease in Dogs

• There is no gender predilection for Legg-Calve-Perthes disease in dogs.
• Most dogs with this disease are diagnosed between three and eight months of age.
• All terrier breeds and most toy breeds are commonly affected by Legg-Calve-Perthes disease. The following breeds are all more prone to this condition than other dogs (Orthopedic Foundation for Animals):

• Affenpinscher
• Australian terrier
• Bichon frise
• Border terrier
• Boston terrier
• Cairn terrier
• Chihuahua
• Cocker spaniel
• Dachshund
• Fox terrier
• Jack Russell terrier
• Lakeland terrier
• Manchester terrier
• Miniature schnauzer
• Miniature pinscher
• Pomeranian
• Pekingese
• Poodle
• Pug
• Schipperke
• Scottish terrier
• Shetland sheepdog
• Silky terrier
• Welsh terrier
• West Highland white terrier
• Yorkshire terrier

Diagnosis of Legg-Calve-Perthes Disease in Dogs

Legg-Calve-Perthes disease is diagnosed through a veterinarian's examination and hip x-rays. The x-rays can also help determine how advanced the disease process is.

Treatment of Legg-Calve-Perthes Disease in Dogs

• Surgery is required in virtually all cases of Legg-Calve-Perthes disease. Once the bone remodels in the wrong shape, the dog will forever experience arthritis and pain. The surgical procedure that is used for Legg-Calve-Perthes disease is a femoral head and neck ostectomy or osteotomy (FHO). This means that the head and neck of the femur is surgically removed.

  Many people are very concerned about what this surgery means for their dog's future. How cana dog walk without a proper ball and socket hip joint? Surprisingly, this procedure producesexcellent results in most dogs. The muscle groups involved in the hip joint do not attach to thehead or neck of the femur, so they aren't disturbed by its removal. Also, these muscle groupsare very large and strong, so they are able to stabilize the area themselves. Lastly, because thisis mostly a problem in toy breed dogs, the hip does not bear a large amount of weight.

• Cage rest is an alternative to surgery that may be used in a small number of dogs affected by Legg-Calve-Perthes disease. The only time this treatment is a possibility is when, as viewed on an X-ray, the hip joint still has its proper shape, and the cartilage is still smooth.

  The dog is placed on strict immobility cage rest. He is carried outside only to urinate and defecate. The rest of the time, he must lie down. Eventually, the blood supply to the head and neck of the femur resumes normal flow, and an X-ray will show that the damage to the bone has been reversed. Because no harm occurred to the cartilage or the shape of the hip joint, the dogs is able to resume normal activities at this point, without pain.

  The downfall of cage rest for treating Legg-Calve-Perthes disease is that the dog must be confined to a cage for, usually, four to six months. This disease affects puppies, and it can be difficult and heart-breaking to prevent them from running and playing for such a long period of time.

• Medications may help control the pain associated with Legg-Calve-Perthes disease before and just after surgery. This does not resolve the condition, but it does help the dog to be more comfortable.

  • Non-steroidal anti-inflammatory medications (NSAIDs) such as Rimadyl and Deramaxx decrease inflammation in the hip joint, helping with pain.
  • Pain medications such as tramadol are helpful for pain before and after surgery, and they work especially well in conjunction with NSAIDs.

Do not give your pet any medications for pain without checking with your veterinarian first. Human medications are often not metabolized the same way in dogs as they are in people and can have devastating effects.

Prevention of Legg-Calve-Perthes Disease in Dogs

Because the majority of cases of Legg-Calve-Perthes disease have a genetic basis, there is no way to prevent its occurrence in individual dogs. Over time, the prevalence of Legg-Calve-Perthes disease could be decreased in the general dog population through responsible breeding practices. Dogs that have suffered from Legg-Calve-Perthes disease should not be used for breeding, as that will perpetuate the disorder.

Prognosis for Legg-Calve-Perthes Disease in Dogs

The prognosis for Legg-Calve-Perthes disease in dogs that have surgery before arthritis sets in is excellent. "With the proper surgical technique, virtually 100 percent of these animals will become ambulatory and free of pain." (Brinker, 1990)

Works Cited

1. Brinker, P. F. (1990). Handbook of Small Animal Orthopedics and Fracture Treatment, Second Edition. Philadelphia: W.B. Saunders Company.
2. Orthopedic Foundation for Animals. (n.d.). Legg-Calve-Perthes Overview. Retrieved from Orthopedic Foundation for Animals.

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