Long-term survivorship of a monoblock long cementless stem in revision total hip arthroplasty

Abstract

Purpose: The purpose of this study was to assess the clinical outcomes, complications, and survival of a long cementless titanium femoral stem in revision total hip arthroplasty (THA) at a minimum five year follow-up.

Methods: Between 2000 and 2010, 114 patients (116 hips), with a mean age of 68 ± 12 years, underwent revision THA using a KAR® stem (DePuy, Leeds, UK). The main reasons for revision were aseptic loosening (82%), periprosthetic joint infections (PJI) (11%), and periprosthetic fractures (6%). Mean follow-up was ten ± three years (range, 5-16). Harris Hip Score (HHS), Oxford Hip Score (OHS), and Postel-Merle d'Aubigné (PMA) score were recorded. Radiographic analysis assessed stem osseointegration and subsidence. Survival was analyzed using the Kaplan-Meier (KM) method and cumulative incidence function (CIF).

Results: Post-operative HHS was 83 ± 15 (range, 35-99) and OHS was 37 ± 8 (range, 8-48). PMA score significantly increased from 12 ± 2 (range, 5-18) pre-operatively to 14.6 ± 2 (range, 9-18) post-operatively (p = 0.0004). The radiographic Engh score was 15 ± 8 (range, 7-22). Stem subsidence was observed in two cases (3%). At ten years, five stems had been revised, three for infections and two for periprosthetic fractures. Using the KM method, ten year survival free of stem revision for aseptic loosening was 100%, free of revision for any reason 95%, and free of any re-operation 81%.

Conclusions: The present study reported satisfactory outcomes and survival of a long tapered unlocked cementless femoral stem in revision THA at a minimum follow-up of five years.

Keywords: Long tapered uncemented stem; Revision; Survival; Total hip arthroplasty.