Heterotopic bone formation after total hip replacement is estimated to occur in about 30% of all patients. It may develop into restriction of mobility and persisting pain.
From 1991 to 1998, 90 patients with uncemented total hip replacement and known risks to develop heterotopic bone formation were treated by radiotherapy (14 patients received 5 x 3 gy between the first and the fifth postoperative day, 13 patients received 1 x 7 gy between 24 hours postoperative, 63 Patients received 1 x 7 gy between 24 hours preoperative) using gamma ray or high-energy photons. The distance between radiation and surgical procedure was never more than 24 hours. Clinical and radiological assessment was carried out 3, 6 and 12 month after surgery.
Independent of the method of radiotherapy no clinically relevant ossification was noticed on the follow up in any of the 90 patients.
The results of this study show the efficiency of radiotherapy in the prophylaxis of heterotopic bone formation, independent of the three applied methods. It seems to be important, that the interval between radiation and surgery is not longer than 24 hours. Because of possible risks and logistic problems preoperative radiation should be preferred over postsurgical treatment.