Perthes disease is a condition that affects the hip in children between the ages of four and eight. The condition is also referred to as Legg-Calve-Perthes disease in honor of the three physicians who each separately described the disease.
In this condition, the blood supply to the growth center of the hip (the capital femoral epiphysis) is disturbed, causing the bone in this area to die. The blood supply eventually returns, and the bone heals.
How the bone heals determines what problems the condition will cause in later life. Perthes disease may affect both hips. In fact, 10 to 12 percent of the time the condition is bilateral (meaning that it affects both hips). This condition can lead to serious problems in the hip joint later in life.
Clearly the problem is one of blood loss called ischemia. The area affected most is the head of the femur (thigh bone). This has been confirmed with today’s modern imaging studies. As a result of this blood loss, the bone dies and starts to collapse. Soon the smooth, round head of the femur starts to flatten and deform.
There is some evidence that LCP can develop after a single episode of ischemia (blood loss) no matter what the cause. But the risk goes up with repeated (multiple) episodes of blood loss. If this proves to be true, then it is essential to predict,
recognize, and stop all ischemic episodes.
Some experts suggest that one way to help prevent the damage done to the hip by this problem is to avoid mechanical pressure on the compromised blood vessels. That could mean keeping the child off his or her feet in a nonweight-bearing state. Limited weight-bearing will protect more than the blood vessels. Compression and load on the joint cartilage, growth plate, and bone will also be reduced.
Although these guidelines make sense, how much pressure and force are put on a child’s hips with different activities is not clear. Your question is a good one. Is running a bigger problem than walking? Is it how often the child is weight-bearing that makes a difference? Or could it be the number of steps taken each day should be limited? And how much does the child’s body weight play a role?
These are just some of the questions that need answers before early and more effective treatment can be prescribed for LCP disease. In the meantime, non-weight-bearing doesn’t have to mean becoming a couch potato.
Swimming, biking, and resistance exercise for the arms are still very acceptable forms of exercise for children with this condition. If you need help designing a program for your son, see a physical therapist. These health care professionals understand this condition and are skilled in prescribing individual exercise programs for specific problems like Legg-Calvé-Perthes disease