Cemented femoral components have been used in hip replacement surgery since its inception. For many patients this works well, but recent retrieval studies1–4 and more fundamental studies5, 6 have highlighted the issues of damage and material loss from the both matt and polished cemented stems. This study will focus on a cohort of retrievals from the Southampton Orthopaedics Centre for Arthroplasty Retrieval Surgery (SOCARS). The cohort consisted of a number of hybrid modular total hip replacements with cemented femoral components, both from mixed and matched manufacturer stem and head combinations. Femoral stems were polished, collarless, tapered designs; head sizes ranged from 28–54 mm. For each femoral stem, samples of Palacos R + G cement (Heraeus Medical GmbH, Hanau, Germany) were retrieved from the proximal region of the cement mantle (Gruen zones 1 and 7), corresponding to both macroscopically damaged and undamaged surfaces of the stem. The areas of damage were determined using calibrated digital photography; damaged surfaces were then imaged in detail using an Alicona InfiniteFocus microscope (Alicona Imaging GmbH, Graz, Austria). The technique uses optical microscopy and focus variation technology to extract 3D morphology and depth information from the surface with a resolution of 10 nm. A series of measurements were made and two different analysis routes were used to provide volumetric material loss measurements from the stem surface. High-resolution microscopy and elemental analysis of the cement and stem surfaces was conducted via SEM and EDX to identify the mechanisms leading to material loss at the cement-stem interface.Introduction:
Materials and methods:
