Midterm Radiographic Comparison of Cementless Acetabular Shells Containing Lateralized and Nonlateralized Liners

This retrospective study assessed the effect of lateralized acetabular inserts on polyethylene wear rates, radiographic loosening, and hip stability. Fifty-six 4-mm lateralized liners and 39 neutral liners were compared at a mean follow-up of 7.1 years. Multivariate regression analysis demonstrated a significant increase of 0.04 mm/y in polyethylene wear rate with use of lateralized liners. However, predictable cementless fixation was obtained without screws in both liner groups with no migration or radiographic signs of loosening observed for any cup. The dislocation rate for hips with lateralized liners (3.6%) was less than that for hip with neutral liners (10.3%), although the difference was not significant with the numbers available. Despite the increase in wear rate, hips with lateralized liners performed as well as those with neutral liners with regard to loosening and stability.