Preoperative radiotherapy without femoral shielding for prevention of heterotopic ossification in hydroxyapatite-coated hip prostheses.

Twenty-seven consecutive patients at high risk of developing heterotopic ossifications (HO) after implantation of a hydroxyapatite (HA)-coated hip prosthesis were irradiated with a single dose of 7 Gy, at least 4 h before the operation. The femoral stem was not shielded during radiotherapy (RT). After a median follow-up of 14.8 months, no clinically significant HO could be found, while 12 (52%) patients in this high-risk population had only minor HO (grade I). No reoperation was needed, and no evidence of prosthesis migration was observed. We conclude that single-dose, preoperative RT for HA-coated hip prosthesis can effectively inhibit HO. Not blocking the femoral stem does not result in prosthesis migration.