Modern acetabular shells have many liner options from which the surgeon can choose to most appropriately reconstruct the arthritic hip. Lateralised liners are one option that is available to the surgeon and these liners have potential benefits over “standard” polyethylene liners. Benefits include decreased Von Mises stresses which may lead to decreased polyethylene wear, lateralisation of the femur away from the pelvis which can decrease impingement / increase ROM and having the ability to use larger femoral heads in a smaller shell improving stability of the THA. Despite these benefits, lateralised liners are not routinely used by surgeons as there is concern over lateralisation of the centre of rotation of the hip with increased joint reaction forces, unsupported polyethylene that could lead to liner failure, and a slightly increased torque moment to the shell which could lead to micromotion and failure of the shell to obtain bony ingrowth. This study reports on 5-year minimum clinical and radiographic F/U of a prospective series of lateralised, moderately crosslinked polyethylene liners. 102 consecutive patients who were to have a THA with a polyethylene liner were enrolled prospectively in an acetabular shell study. Two patients that had standard thickness liners were excluded from this analysis. The remaining 100 patients all had +4 lateralised liners of the same construct (Marathon polyethylene / Pinnacle Cup, DePuy, Warsaw, Indiana). All surgeries were performed by the same surgeon via a posterior approach. A neutral or 10 degree face changing liner was chosen based on shell position and stability of the THA construct. Patient data including the Harris Hip Score (HHS), WOMAC and ROM was collected at 3, 6 and 12 months and yearly thereafter. Radiographs were obtained at each visit.Introduction
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