Liner/shell load transfer mechanisms in a modular acetabular component for total hip replacement

摘要

Modular acetabular components have seen widespread clinical use since the 1980's (Collier et al., 1992). However, nonconformity between the polyethylene liner and the metal shell may exist in modular acetabular components by design, due tolimitations on polyethylene liner manufacturing tolerances, or from the incorporation of locking mechanisms to attach the liner to the shell. Previous research has demonstrated that the stresses at the articulating surface are sensitive to nonconformitybetween the liner and the metal shell (Kurtz et al., 1994). Deleterious rim loading may also occur in a rimmed polyethylene liner with radial interference between the liner and the metal shell (Kurtz et al., 1993).Although backside wear has been documented in the clinical literature (Collier et al., 1992, Guttmann et al., 1994, Huk et al., 1994), evidence suggests that the articulating surface remains the primary source of particulate wear debris. However, since it also appears that backside nonconformity affects the stresses at the articulating surface, one should consider the role of the liner/shell interface during the design of acetabular systems. Researchers have suggested that backside wear may be reduced bylocking mechanisms at the rim and/or equator (Huk et al., 1994). The goal of the current study was to determine the effect of backside nonconformity and locking restraints on liner/shell load transfer mechanisms of a metal-backed acetabular component.