Avascular necrosis of the hip (femoral head)

For a lay person:

Avascular necrosis of the hip happens when the blood supply to the ball of the hip joint is interrupted, so the bone slowly dies and can collapse. It usually causes groin or hip pain that gets worse over time, along with stiffness and limping. It is most common in adults aged 30 to 60, especially after steroid treatment, heavy alcohol use or a hip injury.

For a trained medical person:

Osteonecrosis of the femoral head results from compromised blood supply, either traumatic (femoral neck fracture, dislocation) or non-traumatic, with risk factors including corticosteroids, alcohol, sickle cell disease, coagulopathy and radiation. MRI detects early disease before plain radiographs change, and staging (for example Ficat or ARCO) guides treatment. Early lesions may be managed with protected weight-bearing and core decompression, while collapse and secondary arthritis usually need total hip replacement.

In Chinese medicine:

Liu and Tseng's textbook differentiates this condition into these patterns: Qi Stagnation, Blood Stasis; Qi Deficiency and Blood Stasis; Qi and Blood Deficiency; Liver and Kidney Deficiency; Damp-Heat. Treatment follows the pattern a patient presents with, not the Western diagnosis alone.

When to get help: See a doctor for persistent groin or hip pain, particularly if you have taken steroids or drink heavily, as early diagnosis gives more treatment options. Seek urgent care for sudden severe hip pain or being unable to bear weight.