Atraumatic Femoral Head Necrosis in Adults

Abstract

Background: Atraumatic necrosis of the femoral head is a common cause of hip arthrosis in middle age. In Germany, it affects 5000-7000 patients per year, corresponding to an incidence of 0.01%. Though rarer than primary hip arthrosis, it is still of major clinical and socio-economic significance. Patients with this problem should be diagnosed early and given stage-appropriate treatment.

Methods: This review is based on pertinent publications that were retrieved by a selective search in the PubMed, Embase, Medline, and Cochrane Library databases using the terms "osteonecrosis," "femoral head necrosis," "diagnosis," "classification," "conservative treatment," "surgical treatment," "joint preservation," "osteotomy," and "arthroplasty," as well as a recent guideline on atraumatic necrosis of the femoral head in adults.

Results: The etiology and pathogenesis of atraumatic femoral head necrosis in adults are not yet fully clear. The main risk factor is prolonged corticosteroid treatment. Nonspecific complaints and an initially normal plain x-ray of the hip can delay the diagnosis. The diagnosis is established by plain x-ray, computerized tomography, magnetic resonance tomography, and scintigraphy. Conservative treatment alone is not considered adequate. The range of surgical treatments includes joint-preserving and (for more severe necrosis) joint-resecting methods.

Conclusion: Atraumatic femoral head necrosis in adults is a disease that progresses in stages; depending on its stage, it can either be cured or lead to hip arthrosis. A full cure is possible only in early stages. Current research focuses on the effect of new drugs on the intermediateand long-term outcome.

Figure 1

Diagnostic procedure in the event of suspected atraumatic femoral head necrosis (FHN). MRI, magnetic resonance imaging; FHN, femoral head necrosis; CT, computed tomography; ARCO, Association Research Circulation Osseous

Figure 2

Femoral head necrosis in a 41-year-old patient, ARCO stage III: a) on radiography; b) magnetic resonance imaging (MRI); c) after resection of the femoral head. Plain radiography with the patient standing shows no subchondral fractures or areas of joint surface collapse. The fat-suppressed MRI sequence reveals pronounced bone marrow edema and the zone of necrosis. The resected and divided femoral head (1 month after imaging) displays an area of pronounced necrosis, cystic changes, and a subchondral fracture zone.