Legg-Calvé-Perthes disease is a degenerative disease of the hip joint. It primarily affects young children. A loss of blood supply to the head of the femur (thighbone) can cause collapse of the joint.
It’s not clear what causes Legg-Calvé-Perthes disease. Delay in bone maturation is a common feature of this condition. Scientists think there may be a general disorder of skeletal growth. The hip may be just a local expression of the overall bone delay.
In this study, researchers look at the patterns of bone delay in each of the four stages of the disease. Two different methods of X-ray examination were used: the Tanner and Whitehouse 3 (TW3) system and the Greulich and Pyle (G and P) atlas method.
The G and P atlas method is the most commonly used way to estimate bone age. It is based on a single X-ray of the fingers, hand, and wrist. The bones in the X-ray are compared to the bones of a standard atlas. The overall appearance of the X-ray is matched with the closest standard. This method is not as precise as the TW3 rating.
TW3 is a point-scoring method based on the stage of disease present. Each bone gets its own score. The final bone age is based on the sum of all the scores. This may be the first study to use the TW3 system to study Legg-Calvé disease. Hands, wrists, and hips were X-rayed in 83 patients with unilateral (one-sided) hip disease.
Bone age was compared to the child’s chronological (actual) age. Delays in bone age were seen in the wrist bones during the intermediate stages of this disease. There were no differences in bone age delay in early and late disease.
This finding suggests that delays in bone maturation catch up in the healed stage of the disease. This is called bone maturation acceleration. Bone delays in early stages of the disease have a worse prognosis. These children developed more severe disease. The age of the child at the time the disease begins does not seem to be linked with bone age delays.