Lookup NU author(s): Dr Susan Scholes,
Professor Tom Joyce
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).
Objectives The high revision rates of the DePuy Articular Surface Replacement (ASR) and the DePuy ASR XL (the total hip replacement (THR) version) have led to questions over the viability of metal-on-metal (MoM) hip joints. Some designs of MoM hip joint do, however, have reasonable mid-term performance when implanted in appropriate patients. Investigations into the reasons for implant failure are important to offer help with the choice of implants and direction for future implant designs. One way to assess the performance of explanted hip prostheses is to measure the wear (in terms of material loss) on the joint surfaces. Methods In this study a coordinate measuring machine (CMM) was used to measure the wear on five failed cementless Biomet ReCap/ Magnum/ Taperloc large head MoM THRs along with one Biomet ReCap resurfacing joint. Surface roughness measurements were also taken. The reason for revision of these implants was pain and/or adverse reaction to metal debris (ARMD) and/or raised blood metal ion levels. Results The mean wear rate of the articulating surfaces of the heads and cups of all six joints tested was found to be 6.1 mm3/year (range: 4.1 – 7.6 mm3/year). The mean wear rate of the femoral head tapers of the five THRs was 0.054 mm3/year (range: 0.021 – 0.128 mm3/year) with a mean maximum wear depth of 5.7 µm (range: 4.3 – 8.5 µm). Conclusions Although the taper wear was relatively low, the wear from the articulating surfaces was sufficient to provide concern and was potentially large enough to have been the cause of failure of these joints. The authors believe that patients implanted with the ReCap system, whether the resurfacing prosthesis or the THR, should be closely monitored.
Author(s): Scholes S, Hunt BJ, Richardson VM, Langton DJ, Smith E, Joyce TJ
Publication type: Article
Publication status: Published
Journal: Bone and Joint Research
Online publication date: 28/02/2017
Acceptance date: 08/12/2016
Date deposited: 14/12/2016
ISSN (print): 2046-3758
ISSN (electronic): 2046-3758
Publisher: British Editorial Society of Bone and Joint Surgery
PubMed id: 28246095
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