Introduction
Legg-Perthes disease is a painful disorder that primarily affects young, small-breed dogs and terriers. For some unknown reason, the neck and head of the dog’s femur (the long upper leg bone that joins the pelvis to form the hip joint) spontaneously degenerates and dies, causing the ball-and-socket hip joint to deteriorate and, ultimately, to collapse. Once this happens, the affected dog cannot bear weight on that hip, because the joint has completely lost its structural integrity.
Symptoms of Legg-Perthes Disease
Typically, the owner of an animal with Legg-Perthes disease notices her dog gradually developing varying degrees of lameness in one or both hind legs over the course of several months. The symptoms usually begin when the dog is less than one year of age. In particular, the owner may see one or more of the following signs in their dog:
- Hind limb lameness; gradual onset; one or both rear legs
- Limping
- Pain upon flexion, extension and/or physical manipulation of the affected hip joints and hind legs
- Reluctance to rise, run, jump or play
- Weakness
- Exercise intolerance
- Wasting of the thigh muscles (atrophy)
- Irritability
- Chewing, licking, bothering the affected hip joint
- Audible clicking or snapping coming from the hip joint during movement or when rising (crepitus); unusual early in the disease; becomes more common later in untreated dogs.
When an owner notices progressive lameness in her dog, she should contact the veterinarian promptly.
Dogs At Increased Risk
Legg-Perthes disease occurs most commonly in young miniature, toy and small-breed dogs between 5 and 12 months of age. Manchester Terriers are thought to have a strong genetic predisposition to developing this disorder, and other terrier breeds seem prone to Legg-Perthes disease as well. Predisposed breeds include the Yorkshire Terrier, Manchester Terrier, Miniature Pinscher, Poodle (toy and miniature), Lakeland Terrier, West Highland White Terrier, Cairn Terrier, Australian Shepherd, Chihuahua, Dachshund, Lhasa Apso and Pug.