LONG TERM RESULTS OF A CEMENTLESS SELF-LOCKING TAPERED FEMORAL STEM IN TOTAL HIP REPLACEMENT IN YOUNG PATIENTS

Abstract

Introduction: The Spotorno cementless femoral stem relies on proximal press-fit at time of surgery and subsequent osseointegration for long-term fixation. The aim of the study is to assess the long-term survivorship and clinical outcome of the Spotorno stem used in primary hip replacement surgery in younger patients.

Materials and Methods: 74 patients were identified who had undergone 90 THRs using the Spotorno CLS stem between January 1987 and May 1992. There was variation in the acetabular components used. 5 patients (6 hips) were lost to follow-up, leaving a study group of 84 hips. The patients were assessed using the Harris Hip Score and the Oxford Hip Score.

Results: Mean age at operation was 40.1years (range 23–65years). Commonest diagnoses were primary osteoarthritis, developmental dysplasia of the hip and rheumatoid arthritis. Mean duration of follow-up was 12.25 years (range 8½ – 15yrs 3months). At most recent follow-up, the mean Oxford Hip Score was 23.8 and mean Harris Hip Score was 81. Taking revision for any cause as an end point, 19 hips from the initial group of 84 had undergone some form of revision surgery at most recent review. 15 of the 19 hips that failed had aseptic loosening of the acetabular component, which was the Mecring component, and underwent revision of acetabulum only. Four stems were revised, 2 for loosening and 2 for infection. 80 out of 84 of stems originally implanted remained intact at most recent review, which represents a stem survivorship of 95.2% at mean 12.25yrs follow-up when used in young patients.

Conclusion: Our findings indicate excellent long-term survival of this titanium alloy stem when used in patients under 65years. We attribute this to stem design and the principle of proximal press-fit fixation. Careful consideration must be given to acetabular component selection in cementless total hip arthroplasty.