In this study 45 patients with groin or buttock pain after hemiarthroplasty were evaluated 2 to 7 years after conversion to total hip arthroplasty. Groin or buttock pain was completely relieved in 36 patients (80%) and partially relieved in an additional 4 patients (9%). After conversion surgery, 9 patients continued to have groin or buttock pain, but no factor could be identified that would predict an unsuccessful result. The hypothesis tested in this study was whether conversion of a hemiarthroplasty to a total hip arthroplasty eliminates groin pain. Because a significant number of patients (up to 20%) will continue to have some groin or buttock pain after conversion surgery, patients should be warned of this contingency before surgery.