Introduction. Total Hip Arthroplasty (THA) in patients after proximal femoral osteotomy remains a major challenge. Inferior survival for both cementless and cemented THA has been reported in this subgroup of patients. Methods. We retrospectively evaluated the clinical and radiographic results of a consecutive series of 48 THAs (45 Patients) who had undergone conversion THA for failed intertrochanteric osteotomy after a mean of 12 years (2–33 years) using a cementless, grit-blasted, double-tapered femoral stem. Mean follow-up was 20 years (range, 15–25 years), mean age at surgery was 47 years (range, 13–55 years). Clinical results were evaluated using the Harris Hip Score. Kaplan-Meier survivorship analysis was performed to determine long-term outcomes for different end points. Results. At follow-up, 10 patients (11 hips) had died, and 1 patient (1 hip) was lost to follow-up. Five patients (5 hips) underwent femoral revision, 2 for infection and 3 for aseptic loosening of the stem. Overall stem survival was 91% at 20 years (95%-CI: 78%–97%); survival with femoral revision for aseptic loosening as end point was 93% (95%-CI: 80%–98%). Discussion and Conclusion. The long-term results with this type of cementless femoral component in young patients with failed intertrochanteric osteotomy are encouraging and compare well to those achieved in patients with regular femoral anatomy