Risk Factors for Subsidence of a Modular Tapered Femoral Stem Used for Revision Total Hip Arthroplasty

The purpose of this study was to determine the incidence, and the clinical and radiographic risk factors for significant subsidence of a cementless, modular tapered revision femoral stem. Femoral stem subsidence of at least 10 mm or subsidence requiring revision was considered significant subsidence. Ninety-seven patients (99 hips) were included with minimum radiographic follow-up of one year (mean 34 months; range, 12-91 months). The mean stem subsidence was 4.5 mm (range, 0-44 mm). Fourteen out of 99 (14.1%) stems had significant subsidence and 6 (6.1%) stems required revision due to subsidence. Patient weight greater than 80 kg (P = 0.04) and femoral stem press-fit distance of less than 2 cm (P < 0.01) were both independent risk factors for significant stem subsidence.