[Prevention of heterotopic ossification following cementless hip replacement using 5 x 2 Gy fractionated irradiation. A prospective study].

97 patients were treated with cementless custom-made total hip replacement of the Aldinger type for osteoarthritis of the hip. All were prophylactically treated by radiotherapy with 5 x 2 Gy. 10.3% showed heterotopic ossification. 8 patients showed ossification grade I by the Arcq scale and 2 of grade II. Clinical results according to the Merle d'Aubigné score were good or very good in over 90% at one year postoperatively. One patient showed loosening of the femoral stem caused by sinking-in of the custom-made implant. During the revision procedure there were no signs of radiation induced damage to the implant bed. Negative sequelae to the bony implant bed by prophylactic radiotherapy cannot be detected on radiological assessment. Side effects like delayed wound healing or alteration of local immune status with subsequent infection which are commonly discussed, were not seen. Fractionated irradiation is an effective means of prophylaxis of heterotopic ossification.