Prevention of heterotopic bone formation after total hip arthroplasty: a prospective randomised study comparing postoperative radiation therapy with indomethacin medication

Heterotopic ossification (HO) after total hip arthroplasty is known to be a major complication with an impact on the functional outcome. Efforts have been made to prevent the occurrence of HO by means of either radiation ther apy or pharmacotherapy. To date, there are no data available regarding the relative benefit of radiation versus medication with non-steroidal anti-inf lammatory drugs. The objective of this study was to compare single-dose 600 -cGy radiation therapy with indomethacin medication for their effect on the prevention of heterotopic bone formation after total hip arthroplasty. In all, 154 patients were included in the study. All patients underwent primar y total hip arthroplasty due to osteoarthritis. Patients were randomly assi gned to three different therapeutic groups. (a) The radiation group receive d a single radiation dose of 600 cGy between the 2nd and 4th postoperative day, (b) The indomethacin group received an oral application of indomethaci n 2 x 50 mg per day from the 1st to 42nd postoperative day. (c) The control group received neither radiation nor indomethacin medication. There were s ignificant group differences (P < 0.001). A least significant difference te st (LSD) revealed that the mean of the control group was significantly diff erent from that of the radiation and indomethacin groups. The 13 patients ( 8.4%) classified Brooker 3 or 4 were all in the control group. Again, this effect was statistically significant (chi-square, P < 0.001). In conclusion , this study demonstrated that both radiation and indomethacin therapy are effective in the prevention of postoperative HO. The choice for either one of the treatments has to be based on availability, contraindications, side- effects, practicability, standardisation and cost. Based on these considera tions together with the results of this study, we currently use postoperati ve radiation with 600 cGy for all patients undergoing primary total hip art hroplasty.