Legg-Calve' Perthes disease, frequently referred to simply as Perthes, usually is seen in children 2-12 years of age and is five times more common in boys than girls. It originally was described as peculiar form of childhood arthritis of the hips. Research has shown, however, that Perthes is not a disease. Rather, it is a condition characterized by a temporary loss of blood supply to the hip. When the blood supply is diverted, the femoral head in the hip joint dies and intense inflammation and irritation develop.
The condition usually is diagnosed when the child is brought to the pediatrician and /or orthopaedic surgeon because of pain and /or limping. (An elevated temperature usually is not experienced with this condition.) The child may have had these symptoms intermittently over a period of weeks or even months. Pain sometimes is caused by pathologic fracture or by muscle spasms that accompany hip irritation. The pain may have spread to other parts of the leg such as the groin, thigh or knee. When the hip is moved, the pain worsens. Rest often relives the pain.
Evaluation by the orthopaedic surgeon may not be limited to the irritable hip. The physician may order x-rays of the spine and lower extremities as well. Laboratory (i.e., blood) studies may be necessary to evaluate for related skeletal abnormality or metabolic bone disease.
The child with Perthes can expect to have several x-rays made over the approximate two-year course of treatment. The x-rays usually will look worse and worse before gradual improvement is noted.
Once a diagnosis of Perthes is confirmed, the child will require careful orthopaedic treatment. Although Perthes is self-healing as well as self-limiting. Failure to properly treat this condition may lead to significant femoral head deformity.
Girls tend to have more extensive involvement and, therefore, have a generally poorer prognosis than boys. Usually, treatment for very young children (i.e., those 2-5 years of age) with minimal x-ray changes consists of observation. For the older child in whom the hip is completely involved, vigorous treatment is necessary to maintain the hip and minimize development deformities during the healing process. (Figure 1: Photo of X-Rays)
Treatment includes four stages:
Surgical treatment realigns the bony structures so that the head of the femur is placed deep within the acetabulum. Fixation is maintained within with screws and plates which will be removed at a later date. In some cases, the socket must also be deepened because the ball actually has enlarged during the healing process and no longer fits snugly within. After either procedure, the child is placed into a hip spica (body cast) for approximately six to eight weeks. A reclining wheelchair will provide mobility for the casted child. A rental hospital bed may be necessary for the casted child.
Following cast removal, the child will participate in physical therapy with protected weight bearing of the affected extremity until x-rays reveal the final stages of healing are under way.
Perthes is a complex process in children, and the stages and various forms of treatment may be confusing. Treatment of Perthes may require otherwise healthy children to submit to periods of immobilization or alterations in their usual activities.
Long-term prognosis is good in most cases. After 18 months to two years of treatment, the majority of children return to normal activities without major limitations.