We compared the perioperative morbidity, position of the implants, implant stability, and clinical results of 14 conversion total hip arthroplasties after previous transtrochanteric anterior rotational osteotomy with those of a matched control group of 28 primary total hip arthroplasties. The operation time was prolonged, perioperative blood loss increased, and the risk of stem or cup malposition was increased in the conversion group. However, there were no significant differences in the postoperative complications, clinical results, and implant stability between the 2 groups. None of the implants were loose in both groups. Transtrochanteric anterior rotational osteotomy should be advised, planned, and executed bearing in mind the operative morbidity and technically demanding nature of the conversion total hip arthroplasty.