Avascular Necrosis

Source: http://www.uhms.org/

Avascular necrosis (AVN), or aseptic osteonecrosis, is a serious condition where bone tissue dies due to loss of blood supply. This often affects the femoral head (hip), but also knees, shoulders, and ankles, causing severe pain and potential disability, especially in weight-bearing joints. It typically affects adults in their 40s-50s. Early signs are subtle pain, worsening with weight. Diagnosis relies heavily on imaging; MRI is the gold standard for early detection, showing changes like bone marrow edema before standard X-rays. Severity is often staged using the Ficat classification: Class 1 (pain, normal X-ray), Class 2 (X-ray changes like cysts), Class 3 (femoral head flattens, crescent sign), Class 4 (collapse, joint space narrows). Treatment depends on the stage. Early stages (1, 2, early 3) focus on joint preservation. Late stage 4 usually requires surgery like total joint replacement. Non-surgical options include pain relievers, anti-inflammatories, bisphosphonates, shockwave therapy, and pulsed electromagnetic fields. Core decompression surgery drills channels to relieve pressure and improve blood flow, often for early lesions or combined with other therapies. Hyperbaric Oxygen Therapy (HBO2), breathing 100% oxygen under pressure, significantly boosts oxygen in blood plasma, reaching affected bone. This extra oxygen may reduce swelling/pressure, stimulate new blood vessel growth (angiogenesis), and enhance bone-building cells (osteoblasts), potentially helping bone heal. HBO2 is most promising in early stages (Class 1/2/early 3), with studies showing good recovery, pain control, and potential to delay/avoid surgery. Evidence suggests benefits for AVN in knees and shoulders too. It's accepted in Europe and can sometimes be used after core decompression. Patient selection (before collapse) and lifestyle changes are important. Early diagnosis with MRI is vital to utilize joint-saving options like HBO2.