PURPOSE: To present the results of a prospective study which aimed to evaluate the efficacy of radiation dose in a combined protocol using postoperative radiotherapy (RT) and indomethacin for the prevention of heterotopic ossification (HO) in patients undergoing total hip arthroplasty (THA) and are at high risk for HO development. METHODS: Seventy-one patients with a mean age of 63 years received either a single dose of 7 Gy or a fractionated dose of 10 Gy in 5 fractions of 2 Gy within the 3 postoperative days. Concurrently all patients received 75 mg of indomethacin for 15 days. Patients were analysed for radiographical evidence of HO development and clinically with the Merle d'Aubigné score at 1 year. RESULTS: At 12 months combined RT and indomethacin achieved excellent prophylaxis of HO. The overall radiographical incidence of HO was 7.04% (95% CI 2.33-15.67), while no patient with clinically significant HO (Brooker III-IV) was seen. There was no statistically significant difference between the two RT protocols. In a subgroup of 12 patients with bilateral THA the incidence of HO in the non-irradiated hips was statistically significantly higher compared with the irradiated hips. All patients had improved joint mobility and function during follow up compared with the preoperative period. No statistically significant differences regarding the Merle d'Aubigné score was documented between the 2 RT groups. No acute or late side effects related to RT were noted. CONCLUSION: This study demonstrated the efficacy of combined RT and indomethacin in preventing heterotopic ossification after total hip arthroplasty. Fractionated total dose of 10 Gy seems to offer no further benefit compared to a single dose of 7.0 Gy.
PURPOSE: To present the results of a prospective study which aimed to evaluate the efficacy of radiation dose in a combined protocol using postoperative radiotherapy (RT) and indomethacin for the prevention of heterotopic ossification (HO) in patients undergoing total hip arthroplasty (THA) and are at high risk for HO development. METHODS: Seventy-one patients with a mean age of 63 years received either a single dose of 7 Gy or a fractionated dose of 10 Gy in 5 fractions of 2 Gy within the 3 postoperative days. Concurrently all patients received 75 mg of indomethacin for 15 days. Patients were analysed for radiographical evidence of HO development and clinically with the Merle d'Aubigné score at 1 year. RESULTS: At 12 months combined RT and indomethacin achieved excellent prophylaxis of HO. The overall radiographical incidence of HO was 7.04% (95% CI 2.33-15.67), while no patient with clinically significant HO (Brooker III-IV) was seen. There was no statistically significant difference between the two RT protocols. In a subgroup of 12 patients with bilateral THA the incidence of HO in the non-irradiated hips was statistically significantly higher compared with the irradiated hips. All patients had improved joint mobility and function during follow up compared with the preoperative period. No statistically significant differences regarding the Merle d'Aubigné score was documented between the 2 RT groups. No acute or late side effects related to RT were noted. CONCLUSION: This study demonstrated the efficacy of combined RT and indomethacin in preventing heterotopic ossification after total hip arthroplasty. Fractionated total dose of 10 Gy seems to offer no further benefit compared to a single dose of 7.0 Gy.