The condition is most commonly found in children between the ages of 4 and 10. Common symptoms include pain in the hip, knee, or ankle (since hip pathology can cause pain to be felt in a normal knee or ankle), or in the groin; this pain is exacerbated by hip or leg movement, especially internal hip rotation (with the knee flexed 90°, twisting the lower leg away from the center of the body). The range of motion is reduced, particularly in abduction and internal rotation, and the patient presents with a limp. Pain is usually mild. Atrophy of thigh muscles may occur from disuse and an inequality of leg length. In some cases, some activity can cause severe irritation or inflammation of the damaged area, including standing, walking, running, kneeling, or stooping repeatedly for an extended period of time. In cases exhibiting severe femoral osteonecrosis, pain is usually a chronic, throbbing sensation exacerbated by activity. The first signs are complaints of soreness from the child, which are often dismissed as growing pains, and limping or other guarding of the joint, particularly when tired. The pain is usually in the hip, but can also be felt in the knee (referred pain). In some cases, pain is felt in the unaffected hip and leg, due to the children favoring their injured side and placing the majority of their weight on their "good" leg. It is predominantly a<unk>  of boys (4:1 ratio).<unk>  is generally diagnosed between 5 and 12 years of age, although it has been diagnosed as early as 18 months. Typically, the<unk>  is only seen in one hip, but bilateral<unk>  is seen in about 10% of children diagnosed.
Legg–Calvé–Perthes disease
Langer–Giedion syndrome
Osgood–Schlatter disease
Avascular necrosis
Iliotibial band syndrome
Löfgren syndrome
Patellar subluxation syndrome
Boxer's fracture