Kendrick B J L, Simpson D J, Kaptein B L, Valstar E R, Gill H S, Murray D W, Price A J
Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Biomedical Research Unit, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD, UK.
J Bone Joint Surg Br. 2011 Apr;93(4):470-5. doi: 10.1302/0301-620X.93B4.25605.
The Oxford unicompartmental knee replacement (UKR) was designed to minimise wear utilising a fully-congruent, mobile, polyethylene bearing. Wear of polyethylene is a significant cause of revision surgery in UKR in the first decade, and the incidence increases in the second decade. Our study used model-based radiostereometric analysis to measure the combined wear of the upper and lower bearing surfaces in 13 medial-compartment Oxford UKRs at a mean of 20.9 years (17.2 to 25.9) post-operatively. The mean linear penetration of the polyethylene bearing was 1.04 mm (0.307 to 2.15), with a mean annual wear rate of 0.045 mm/year (0.016 to 0.099). The annual wear rate of the phase-2 bearings (mean 0.022 mm/year) was significantly less (p = 0.01) than that of phase-1 bearings (mean 0.07 mm/year). The linear wear rate of the Oxford UKR remains very low into the third decade. We believe that phase-2 bearings had lower wear rates than phase-1 implants because of the improved bearing design and surgical technique which decreased the incidence of impingement. We conclude that the design of the Oxford UKR gives low rates of wear in the long term.
牛津单髁膝关节置换术（UKR）旨在通过使用完全贴合、可活动的聚乙烯衬垫来减少磨损。在最初十年中，聚乙烯磨损是UKR翻修手术的一个重要原因，而在第二个十年中，其发生率会增加。我们的研究采用基于模型的放射立体测量分析，对13例内侧间室牛津UKR术后平均20.9年（17.2至25.9年）时上下衬垫表面的联合磨损情况进行了测量。聚乙烯衬垫的平均线性穿透为1.04毫米（0.307至2.15），平均年磨损率为0.045毫米/年（0.016至0.099）。2期衬垫的年磨损率（平均0.022毫米/年）显著低于（p = 0.01）1期衬垫（平均0.07毫米/年）。直至第三个十年，牛津UKR的线性磨损率仍非常低。我们认为，2期衬垫的磨损率低于1期植入物，是因为衬垫设计和手术技术得到改进，降低了撞击发生率。我们得出结论，牛津UKR的设计长期磨损率较低。
