Avascular necrosis of the humeral head may long go undetected because the shoulder is not a weight-bearing joint and symptoms may be transient or mild. Pain commonly radiates to the deltoid tuberosity of the humerus. Active motion is limited very early, but passive motion is preserved. Avascular necrosis of the humeral head without other sites of involvement is rare. Diagnosis Early diagnosis requires a high index of suspicion in patients presenting with pain, particularly of the hips, knees, or shoulders.
Diagnostic testing depends on the stage of the disease.
MRI is the most sensitive and specific technique and should be used for very early diagnosis, when collapse of the femoral head or other bone may be preventable. If duration of disease is not clear, an x-ray or CT scan should be obtained to rule out advanced disease. X-ray findings may not become apparent for months to up to 5 yr after symptom onset. Characteristics seen on x-ray begin with subtle sclerosis of bone. Prevention and Treatment Prevention is obviously preferable to treatment.