Conversion total hip arthroplasty after previous transtrochanteric rotational osteotomy for osteonecrosis of the femoral head.

The results of conversion total hip arthroplasty (THA) after failed transtrochanteric rotational osteotomy (TRO) are still controversial. We retrospectively reviewed 18 patients with ONFHs who had been treated previously by TRO and were later converted to THAs (conversion group). We made a matched control group of 18 primary THAs for ONFH done by same hip surgeon (PTHA group). There was an improvement in the Harris hip score and WOMAC score at the final follow-up but the improvement was not statistically significant between the two groups. Only internal rotation was significantly better in the PTHA group than in the conversion group. THA after TRO provides satisfactory clinical and radiological outcomes with no significant increase in perioperative morbidity in comparison with that in the primary THA.