Abstract
Introduction
Many patients who had previous proximal femoral osteotomies develop deformities that may not be amenable to total hip replacement (THR) with standard off-the-shelf femoral stems. Previous studies have shown high revision rates (18% at 5–10 years follow-up). Computer-assisted-design computer-assisted-manufacture (CAD-CAM) femoral stems are indicated but the results are not known. We assessed the clinical results of THR using CAD-CAM femoral stems specifically for this group of patients.
Methods
We included patients with previous proximal femoral osteotomy and significant deformity who underwent THR with CAD-CAM femoral stem operated by the senior author (AHN) from 1997 with a minimum of 5 years follow-up. We noted revision rates, associated complications and functional outcome. Radiological outcomes include assessment for loosening defined as development of progressive radiolucent lines around implant or implant migration.
Results
We included 54 patients (57 THRs) at a mean age of 32 years (range 19 to 49) with a mean follow-up of 9.1 years (range 5.9–12.8). There was 2 (3.5%) stem revision for loosening. Seven polyethylene liners were revised because of eccentric wear/osteolysis after a mean of 10 years (range 7–11.5) but there was no associated radiological stem loosening. Other associated complications include 2 (3.5%) intraoperative femur fractures, 1 (1.8%) infection treated with antibiotics and 1 (1.8%) greater trochanteric fracture non-union. At the last follow-up review, the mean Oxford hip score was 35 (11–48) and the mean UCLA activity score was 5.1 (3–10).
Conclusion
In contrast to previous studies that have shown high revision rates for THR in patients with previous proximal femoral osteotomy and osteotomy, the use of CAD-CAM hip stems has shown good mid- to long-term clinical outcomes with a considerably lower revision rate.
