Total hip arthroplasty after failed curved intertrochanteric varus osteotomy for avascular necrosis of the femoral head

Curved intertrochanteric varus osteotomy (CVO) is one of the good surgical procedures for avascular necrosis of the femoral head (ANFH) patients. However, some patients with failed CVO are converted to total hip arthroplasty (THA) as a salvage operation. We compared the clinical and radiographic outcomes of 10 hips converted to THA after failed CVO (Group O) (mean age 43.0 years, 8 male and 2 female) with an age and gender matched control group of 20 hips that underwent primary THA for ANFH (Group C). Perioperative blood loss in Group O was significantly higher than that in Group C (535 g vs 282 g (P = 0.002)). Infection and dislocation occurred in 1 and 2 hips in Group O. There were no significant differences in both pre- and post-Harris Hip Score (HHS) between the groups. The stems in the AP radiograph were placed at 2.1° in a valgus position in Group O, whereas those in Group O were inserted at 1.0° in a varus position, a significant difference (P = 0.01). The stem alignment in the Lauenstein view in Group O was 1.2° in the extension position and in Group C was 0.4° in the flexion position, a significantly difference (P = 0.04). THA after failed CVO provides with the stem inserted in a valgus and extension position. Operative bleeding was increased. THA after failed CVO is a technically demanding arthroplasty. We believe that careful preoperative planning and preparation are necessary for this arthroplasty.