Avascular Necrosis Osteonecrosis of the Hip
What is it: The death of the bone of the femoral head caused by a disruption of the vascular supply. Common risk factors include trauma, corticosteroid use and alcoholism.
How does it present: Patients will usually present with pain in the groin or buttock. Secondary arthritis develops with progressive collapse of the femoral head and symptoms may be indistinguishable from osteoarthritis.
Common exam findings: Pain with attempted straight-leg raise and hip range of motion testing (see complete musculoskeletal exam of the hip video). Faber (Patrick) Test is usually positive. Patients often have an antalgic gait and may develop a Trendelenberg gait once secondary arthritis develops.
Tests and treatment: AP view of the pelvis along with lateral and frog-legged views of the hip should be ordered. Radiographs may appear, in which cases MRI may be needed to make the diagnosis. Treatment should include limiting weight bearing and referral to an orthopedic surgeon.