[Surgical treatment of radiation-induced lesions of the hip in adults].

The authors report their experience in the surgical management of lesions of the adult hip following radiotherapy. The diagnosis of a hip problem occurring after pelvic radiotherapy for malignant tumors is made by clinical and radiological examination. The problems include femoral head necrosis, necrosis and/or fracture of the acetabulum, or involvement of the entire hip joint (radiation coxopathy). Fractures of the femoral neck have been described in the literature, but are now very rare following the routine use of external shields as protection during irradiation. Post-irradiation lesions are often bilateral 21%. They appear after a variable latency period of two to twenty years and they progress remorselessly. A diagnosis of simple radio necrosis can only be made after using radio isotope bone scanning, MRI or CT to exclude malignant disease as acetabular metastasis, and radio-induced sarcomas. Hemiarthroplasty is often followed by collapse of the acetabulum and should no longer be used. The treatment generally practised nowadays is a Total Hip Replacement (THR). We report a retrospective study of 71 hips in 56 patients treated, between 1970 and 1982, by the use of conventional cemented components. In 49 hips this was followed by a 52% incidence of acetabular loosening resulting from the poor quality of the irradiated bone which had become necrotic and porotic. Between 1983 and 1990, we modified the technique by regularly using reinforcing the acetabulum with a metallic ring fixed by long screws, (as used in revision surgery for THR). Bone grafts were also used in 9 cases. We had a 12% incidence of loosening in 22 hips with a mean follow-up of 40 months. There were also two post-operative infection which need removal of the prostheses. This emphasizes the risk of infection in this type of surgery and is probably increased by the associated lesions of the soft tissues (lymphoedema, radiodermitis). The authors wish to stress the poor prognosis of radiation lesions of the hip which often occur in patients who have otherwise recovered from their pelvic tumour. These radiation lesions have to be recognised and treated in a specific way. Our experience and the reports in the literature suggest that the generally used conventional THR gives uncertain results, and therefore we propose a THR employing metallic reinforcement of the acetabulum with or without any necessary bone grafts. It is vital to warn the patients that the results may not be as excellent as with THR for other types of hip disorders. When there is severe destruction of the acetabulum the choice between a THR combined with massive bone allograft, and a Girdlestone hip resection must be very carefully discussed with the patient. This latter "salvage" procedure may in any case become necessary if there are local and otherwise unmanageable problems.