What is Perthes Disease?
Perthes disease is a disorder of the hip joint in children caused by a temporary loss of blood supply to the femoral head. The lost blood supply causes the femoral head to soften, collapse and become flattened. It no longer fits perfectly in its socket resulting in deformity of the hip joint. As the condition occurs in children with joints which are still growing, the hip has the potential to recover, although normal growth and development of the joint can be disrupted.
What is the natural course of Perthes Disease?
This depends on many factors; however the age of the child is perhaps the most important predictor of outcome. Generally, the older the child when first diagnosed with Perthes disease, the worse the outcome. The long term outcome of the hip after Perthes diease depends mostly on the degree of deformity remaining in the joint at the end of skeletal growth (around age 16-18 years). Hip joints with significant irregularity in shape are predisposed to early onset osteoarthritis. Severe deformity due to Perthes disease typically includes a flattened femoral head (ball of the hip joint) and characteristic changes of the upper thigh bone resulting in a stiff hip and short leg.
What is the initial treatment?
Treatment aims to reduce hip pain and stiffness, and prevent deformity of the femoral head and will depend on the age at diagnosis and the severity of the hip deformity. Generally speaking, young children have a good chance of excellent outcomes with observation alone. In older children and adolescents, surgery is sometimes recommended to help assist the joint develop a normal round shape.
What is the treatment for adults with previous Perthes?
This depends on the presenting symptoms, shape of the hip joint and how much damage there is within the joint surfaces. Many patients can improve their symptoms without surgery, however any deformities present are permanent. Once the joint has become painful, it is likely to gradually worsen.
Pain secondary to early damage to the hip may be relieved with joint preserving procedures such as hip arthroscopy (key hole surgery). The joint deformity requires more complex surgery. Femoral Osteotomy may be recommended to improve function of the joint, decrease pain and restore leg length. Open Debridement can also be used to reshape the joint. Pelvic osteotomy may be recommended if the hip joint socket is abnormally shallow. Joints with osteoarthritis are best treated with an artificial joint replacement. In these situations, both hip replacement and hip resurfacing are effective solutions.