This irregularity may lead, much later, to subsequent degenerative joint disease. The most common presentation is an insidious onset of a limp. Pain can be either absent or mild in nature. When pain is present, it is usually activity related and relieved by rest. Pain is usually in the groin area, but can be referred to the anteromedial thigh or knee.
Physical exam is notable for limited abduction and internal rotation.
Atrophy of the thigh, calf, and buttock can be present from disuse. Leg length inequality is a late finding. Classification Classification systems are all based on radiographs - the extent of involvement of the femoral head. In the Catterall staging, stage I involves only the anterior femoral head. State II involves the entire medial dome.