Legg-Calve-Perthes Disease is a childhood disease involving disruption of blood supply to the head of the femur. The cause of this disruption is unknown, but it can lead to the development of avascular necrosis. Avascular necrosis is followed by regeneration of the blood supply and a healing phase, which involves remodeling of the bone. The bone of the femoral head often heals irregularly, causing a misshapen femoral head leading to mechanical issues and pain as the child grows.
Legg-Calve-Perthes disease, though rare, is more common in males between 4-10 years of age. Individuals typically complain of hip, groin, or knee pain, and can have a limp, stiffness, or limited range of motion in the affected hip joint. Legg-Calve-Perthes disease typically resolves on its own. However, it is the long-term consequences, such as uneven leg lengths and early osteoarthritis that treatment aims to prevent.
The choice of treatment depends on the age of the child and extent of the disease. Non-surgical treatment includes pain medications, physical therapy, and use of a Petrie cast. In more advanced cases, surgical intervention including an osteotomy to reshape and reform the head of the femur may be warranted.
Legg-Calve-Perthes Disease is a childhood condition that develops as a result of loss of blood supply to the head of the femur. The exact mechanism of the blood supply loss is not known, but the result of this disruption is avascular necrosis (bone death). Over time, blood supply returns to the area of avascular necrosis, and new bone beings to form. This new bone often forms irregularly, creating a “bumpy” surface on the head of the femur as opposed to a smooth one. A misshaped or uneven femoral head will eventually lead to hip and groin pain, limited range of motion, and uneven wear of the hip joint causing early hip arthritis.
The typical age of development of Legg-Calve-Perthes disease is between 4-10 years old. Males are more likely to be affected than females, at a ratio of 4:1. However, females are more likely to develop a more severe form of the disease. Additionally, the disease usually occurs only in one hip but can sometimes occur in both hips at once.
One of the earliest signs of the disease is the development of a limp with walking, usually worse after activity. Individuals may also present with pain. The pain is commonly mistaken for “growing pains,” and can be located in many different areas such as over the groin, front or side of the upper thigh. The pain can also be referred to the knee on the same side as the diseased hip. In rare cases, the pain can occur in the opposite leg due to a change in the mechanics caused by walking with a limp. Limited range of motion and stiffness in the hip joint may also be present.
Findings in Legg-Calve-Perthes Disease include limitations with range of motion testing, most commonly manifesting as restrictions in outward movement of the hip (abduction) and internal rotation, or movement such that the knee is pointing toward the center of the body. Pain and guarding, or involuntary muscle contraction to prevent movement, may be present when testing range of motion.
The disease process can also cause a flexion contracture, or forward position of the thigh without the ability to straighten due to shortening of the muscles that control hip flexion. There may also be atrophy of the gluteal muscles and an abnormal walking pattern call a Trendelenberg gait. A child with this type of gait appears to sway or “lurch” towards the affected side when walking.
X-rays are the main imaging used in the diagnosis of Legg-Calve-Perthes disease. X-rays may appear very normal early on in the disease and individuals typically receive multiple x-rays over the course of 2-5 years. The reason for multiple x-rays is that the disease tends to evolve over a period of time. The disease progresses through well-defined stages, with x-rays revealing progressive deformity of the femoral head.
Other imaging such as an MRI is occasionally used if the diagnosis is in question or to better characterize the severity of the condition. MRI can also be used to see damage caused by Legg-Calve-Perthes disease before it shows up on x-ray.
A bone scan is another tool used for the diagnosis and treatment of this disease. Bone scans involve injecting a small amount of radioactive material into the body that shows areas of rapid bone breakdown and remodeling, which occurs in the affected hip in individuals with Legg-Calve-Perthes Disease.
Legg-Calve-Perthes disease often resolves on its own, with the symptoms usually disappearing within 18 months of diagnosis and healing and remodeling of the bone taking up to 4-5 years to complete. Treatment is required in many cases because the death and breakdown of bone followed by remodeling can result in the head of the femur no longer fitting smoothly into the acetabulum.
Younger children who have less extensive forms of the disease may not require surgery and can be treated with non-operative measures. Ibuprofen, an anti-inflammatory medication, is used to both relieve the pain and decrease inflammation. Exercises programs and physical therapy can be used to help strengthen muscles around the joint and prevent muscle wasting, weakness, stiffness and contracture. Activity modification, which can include limiting weight bearing on the affected side for a period of time with the use of crutches or bed rest may be recommended. In addition to bed rest, traction and casting may be used. Traction involves gently applying a stretching force to the affected leg. Casting is done to keep the femoral head in close contact with the acetabulum. A specific type of cast known as a Petrie cast is used. The cast keeps the legs spread wide apart and in the best position for healing.
Surgery for Legg-Calve-Perthes disease is typically performed in older children with a more advanced form of the disease. Surgical treatment may involve any one of a variety of operations, which are utilized depending on the extent of the disease.
The mainstay of surgical treatment is an osteotomy to remove and reshape part of the hip joint so the femoral head fits more smoothly and congruently within the acetabulum. In the case of Legg-Calve-Perthes Disease, an osteotomy of either the femur or the pelvis can be performed to better align the bones. Children with flexion contractures (inability to straighten the joint) may also require a contracture release procedure, aimed at improving range-of-motion in the affected hip joint.