Legg-Calvé-Perthes Syndrome (Perthes Disease)

Definition:
Legg-Calvé-Perthes syndrome is a degenerative disease of the hip joint, where a loss of bone mass leads to some degree of collapse of the hip joint, that is, to deformity of the ball of the femur and the surface of the hip socket. The disease is typically found in young children and small dogs, and it can lead to osteoarthritis in adults. Perthes can also sometimes continue into adulthood.
It is the idiopathic avascular osteonecrosis of the capital femoral epiphysis of the femoral head. It is caused by an interruption to the blood supply of the head of the femur close to the hip joint. It is equivalent to adult avascular necrosis.

Cause:
The direct cause is a reduction in blood flow to the joint, though what causes this is unknown. It is thought that the artery of the ligamentum teres femoris closes too early, not allowing time for the medial circumflex femoral artery to take over.[citation needed]Genetics does not appear to be a determining factor, though it may be involved. When the disease is genetic in origin, it typically runs along the male line. Some evidence suggests that parental smoking may be a factor, though this is not yet proven, or more recently that a deficiency of some blood factors used to disperse blood clots may lead to blockages in the vessels supplying the joint, but that, too, has not been proven.

Symptoms:
Symptoms are hip or groin pain, exacerbated by hip/leg movement. There is a reduced range of motion at the hip joint and a painful or antalgic gait. There may be atrophy of thigh muscles from disuse and an inequality of leg length. In some cases, some activity can cause severe irritation or inflammation of the damaged area including standing, walking, running, kneeling, or stooping repeatedly for an extended period of time.
Signs:
The first signs are complaints of soreness from the child, particularly when tired. The pain is usually in the hip, referred to the knee. It is predominantly a disease of boys (4:1 ratio). Whereas Perthes is generally diagnosed between 5 and 12 years of age. Typically the disease is only seen in one hip.

Treatment:
The goal of treatment is to avoid severe degenerative arthritis. Orthopedic assessment is crucial. Younger children have a better prognosis than older children. Currently, there are studies conducted on bisphosphonates for treatment of Perthes. Analgesic medication may be given as necessary.