Re-irradiation to prevent ectopic bone formation after major hip surgery. 
Ectopic bone formation may occur after total hip arthroplasty, but fortunately most patients are asymptomatic.  Both pre-operative and post-operative radiotherapy are effective in prevention of ectopic bone formation.  In the few patients who needed re-operation, we found that re-irradiation is possible and safe.  This case report presents our experience with single dose reirradiation of the hip in an attempt to prevent post-operative ectopic bone formation.