What common physical exam finding in a child with Legg-Calve-Perthes disease should be noted?

In the context of Legg-Calve-Perthes disease, quadriceps atrophy is a common physical exam finding. This condition involves avascular necrosis of the femoral head, leading to pain and limited range of motion in the hip joint. Because the hip is typically affected, children often avoid using that leg due to pain, resulting in disuse of the muscles around the hip, particularly the quadriceps. Over time, this disuse leads to muscle atrophy, making it a significant and observable finding during examination.

The other options involve findings that are less characteristic of this disease process. For instance, hip hyperextension is not a typical compensatory mechanism seen in these patients; instead, children may present with a limited range of motion, particularly with internal rotation and abduction. A leg-length discrepancy may occur in some cases, but it is not as prominent or obvious as the muscle atrophy that arises from reduced use of the affected limb. Calf hypertrophy also does not relate directly to Legg-Calve-Perthes disease, as the condition specifically affects the hip rather than promoting increased muscle growth in the lower leg. Thus, quadriceps atrophy emerges as a key indication of the impact of this disease on a child's activity