Once Perthes disease is healed, the shape of the ball and socket joint may allow for nearly normal range of motion. In this circumstance, there is typically no need for further treatment. Occasionally, exercises or therapy to strengthen muscle weakened during the healing process can improve function.
If the ball and socket joint healed not round but flat or mushroom shaped then there may be a mismatch between the bones with certain movements. This may produce hip pain with certain movement due to the mismatch. This conition is called femoro-acetabular impingement (FAI). Several options exist for the treatment of FAI. A minimally invasive surgery, called an arthroscopy, may be able to remove excess bone from the ball or socket to allow for better movement. Torn cartilage and soft tissue may also be able to be repaired during an arthroscopy. For more severe impingement, an open procedure allows the surgeon full access to the hip joint to treat impingement and to improve hip motion such as by reshaping of the hip joint. It is important to note that neither arthroscopy nor an open surgical procedure can replace worn out cartilage or recreate a perfectly round ball and socket joint.
The Stulberg Classification system for healed Perthes disease is used to evaluate the shape of the femoral head and how it fits into the acetabulum. These images demonstrate possible outcomes for hips with Perthes disease.
For patients with healed Perthes disease and a severe deformity or severe pain, joint replacement surgery may the best option. This involves removing the misshaped ball and socket and replacing it with artificial material. Since hip replacement is a procedure for adults and not children, pros and cons of having this procedure must be carefully weighed.