What is Perthes?
Perthes Disease, also known as Legg-Calvé-Perthes Disease, was described early in the 20th century, almost simultaneously, by the three doctors for whom it is named. This hip problem causes pain and limping in children. The limp may begin very mildly, even painlessly, without any notice of injury.

Gradually, the affected child limps more and may complain of pain in the groin, thigh, or knee. The hip becomes stiffer, particularly in the direction of sideways away from the body (keeping one from doing the “splits”).

What Causes Perthes?
Perthes is apparently the result of a temporary loss of the blood supply to the ball of the hip joint (the head of the femur). This loss of nourishment leads to the death of the femoral head, and its eventual collapse and flattening. This, in turn, leads to pain and stiffness. The reason blood supply to the head of the femur is lost remains under investigation.

In the course of the disease the blood supply returns. This allows the body to replace the dead bone with living bone and the femoral head heals and re-constitutes. Long-term results are best in those hips which return to spherical shape.

How Is the Diagnosis Made?
The diagnosis of Perthes is usually made on the basis of x-rays. Occasionally, early cases will have normal x-rays and will require other diagnostic studies, such as an MRI.

What Happens to Children with Perthes?
The outlook for children with Perthes Disease varies considerably. Children with the mildest cases will limp briefly, return to normal, and have no further problems. Others with severe disease may have persistent pain and limp into, and throughout, adulthood.

The prognosis appears related to the amount of femoral head involved and to the age of the child at disease onset. Children with lesser degrees of head involvement do better, as do those who are younger when the disease first appears.

Can Treatment Improve the Prognosis in Perthes Disease?
Some children are young enough and have mild enough involvement of the hip that no treatment is needed. For others, it appears that treatment can improve the long-term outlook, increasing the chance of obtaining a hip that can withstand the demands of adult life.

Treatments fall into three broad categories
1) Relieve symptoms
2) Decrease stiffness
3) Increase “containment” of the femoral head

What Can Relieve the Pain of Perthes?
Children with early or mild disease are often restricted from running and jumping activities. Increased activity seems to increase inflammation about the hip, which increases pain and stiffness. Anti-inflammatory medications (such as ibuprofen or naproxen) may be helpful in controlling symptoms as well.

How Can Hip Stiffness be Decreased?
Physical Therapy may help a child with mild stiffness increase range of motion. Parents can learn techniques to help the child stretch at home.

Traction may be helpful, although the requirement that the child remain in bed may make this less practical.
Petrie Casts are casts on both legs, from thigh to ankle, with bars in between to keep the legs spread apart. These are left on for several weeks. Younger children will learn to “walk” in the cast with a swivel-type gait. A wheelchair will be needed for transportation of any distance.

The casts are often applied in the operating room, with the child under anesthesia. Surgical lengthening of contracted muscles can be performed under the same anesthetic, as well as fluoroscopic (real-time x-ray) examination of the hip. X-ray contrast dye may be placed in the hip joint to outline the non-calcified portions of the ball and socket (a hip arthrogram). This may aid in planning future treatment.

What is Containment Treatment?
It appears that the hip socket can help shape the healing head of the femur into a sphere if the head remains “contained” within the confines of the socket. This is said to be like an ice cream scoop shaping ice cream into a ball. However, as the femoral head flattens, some of the head often protrudes outside the socket. This may lead to continued deformity of the head after healing, and long-term stiffness and premature arthritis.

Containment treatment attempts to keep the femoral head covered by the socket during the vulnerable healing period. This has historically been accomplished by bracing or surgery. Recent studies have questioned the effectiveness of braces. Surgery consists of altering the shape of the pelvis or of the femur to increase coverage and containment. These treatments do not speed healing time, but may improve the long-term outlook in Perthes.

Surgery on a stiff hip can lead to even greater stiffness. For this reason, attempts are made to decrease hip stiffness prior to any major surgery. This usually takes the form of muscle lengthening and Petrie casting (see above).

What is the Long-Term Outlook?
Progressive flattening, consolidation, healing, and re-growth of the femoral head may take several years. Long-term results relate to the risk of arthritis and pain in adulthood. The best results occur in those patients with a spherical femoral head in a matching spherical hip socket. Intermediate results are seen with an oval femoral head in a matching oval socket.

The worst results occur when the femoral head remains flattened, located in a round socket. This mis-match leads to early arthritis.

It is the aim of treatment to assist the femoral head to heal in a spherical shape.