Re-irradiation for prophylaxis of heterotopic ossification after hip surgery

Heterotopic ossification (HO) may occur after total hip arthroplasty, but f ortunately most patients are asymptomatic. Rick factors for HO include prev ious HO, hypertrophic osteoarthritis, diffuse idiopathic skeletal hyperosto sis, ankylosing spondylitis, Paget's disease and post-traumatic arthritis. Both pre-operative and post-operative radiotherapy are effective in the pre vention of HO in 85-95% of high-risk patients treated. In the few patients who needed re-operation for a variety of reasons, we found that re-irradiat ion is possible and safe. These case reports present our experience with si ngle dose re-irradiation of the hip in an attempt to prevent post-operative HO.