[Usefulness of electromagnetic fields in the treatment of hip avascular necrosis: a prospective study of 30 cases].

A series is here reported of 30 hips from 21 patients with the diagnosis of avascular necrosis in different stages (Ficat 0 = 1, I = 4, II = 13, III = 10, IV = 2). Patients underwent external electro-stimulation by means of a electromagnetic field generator, and results were evaluated by NMR at three-month intervals. Lesions were categorized by NMR: < 25%, 25%-50%, and > 50% of involved head volume. The grading of lesions yielded the following distribution: grade 1 = 12, grade 2 = 10, and grade 3 = 7. Results were categorized in "clinical success", "NMR success" and "combined success" when symptoms decreased or disappeared, the lesion stabilized by NMR, or both, respectively. Overall, the corresponding figures were 80%, 76.6%, and 63.3%, and were remarkably influenced by the NMR grading of the lesion.