By Waikeong P. Wong, MD, PhD

History

A 43-year-old man with a history of alcohol abuse, pancreatitis, and chronic liver disease presented with left hip pain.

Diagnosis

Avascular necrosis of femoral head

Clinical

• Patients may be asymptomatic early in the disease process but ultimately present with pain and limitation of motion.

• Pain is most commonly in the groin area but may also manifest in the ipsilateral buttock, knee, or greater trochanteric region.

• Pain is usually exacerbated with weight bearing and relieved with rest.

• Predisposing factors include corticosteroids, alcohol abuse, chronic liver disease, pancreatitis, coagulopathy, and hemoglobinopathies; traumatic etiologies include femoral neck fracture, hip dislocation, and slipped capital femoral epiphysis.

Key Diagnostic Features (MRI)

• MRI is the most sensitive modality and demonstrates changes well before plain film changes are visible.

• Diffuse edema

• Serpiginous low T1 signal line

• Double line sign: inner high T2 signal line representing granulation tissue and outer low signal line representing sclerotic bone at the periphery of osteonecrotic region

Differential Diagnosis

• Femoral neck stress fracture

• Synovitis

• Idiopathic transient osteoporosis of the hip

• Chondroblastoma

• Metastatic disease

Treatment

Treatment varies with location and stages of osteonecrosis: conservative (anti-inflammatory, analgesia, non-weight bearing), core decompression, and joint replacement for end-stage disease.

— Waikeong P. Wong, MD, PhD, is a radiology resident at Saint Barnabas Medical Center in Livingston, New Jersey.