Perthes Disease, also known as Legg-Calvé-Perthes, is one of many possible causes of hip pain in children 5-12 years old.
A child with Perthes will limp and sometimes complain of thigh or knee pain. Persistent limping is what generally leads to a doctor’s evaluation and eventual referral to a pediatric orthopedist.
It is widely believed that Perthes is caused by idiopathic avascular necrosis of the femoral head, a condition arising spontaneously from an unknown cause (idiopathic) in which the top section of the thigh bone that makes contact with the hip socket (the femoral head) dies due to lack of blood supply (avascular necrosis).
The blood supply to the femoral head is compromised; and scientists, as well as physicians, do not know why this occurs. The bone of the femoral head collapses and then regrows and remodels. The entire process takes approximately two years.
During this time, the pediatric orthopedist will monitor the child through regular follow up appointments every 4-6 months to check hip range of motion, gait (walking pattern) and pelvic radiographs (x-rays).
Depending on the child’s physical exam findings and x-rays, treatment will range from non-steroidal anti-inflammatory medications (NSAIDS, such as ibuprofen) and activity modification (avoidance of running and jumping activities) to brace treatment, casting, or possibly surgery.
Figure 1: Typical x-ray appearance of an 11-year-old child in the early stages of Perthes disease
Figure 2: Eight months later, the femoral head is collapsing and fragmenting (as depicted by the white arrow).
Figure 3: Ten months after the first x-ray (Figure 1), the femoral head is very irregular at this point and is subluxating (coming out of the socket). Surgery is recommended to re-direct the femoral head into the socket (acetabulum) to promote the best chance of healing.
Figure 4: Surgery has been performed. The femoral has been cut, a metal plate is attached, and the femoral head is redirected into the acetabulum.
Children with Perthes need to be mindful of their lifelong physical activities. Participation in hip joint preserving activities, such as swimming or biking, rather than running and jumping sports, will prolong the possible need of hip replacement surgery as an adult.
Physical therapists play an important role in the care of patients with Perthes. The physical therapist will work with the child on range of motion and strengthening exercises for the lower extremities, as maintaining strength of the lower extremities and range of motion of the affected hip is very important in the rehabilitation of a child with Perthes disease.