Ilchmann T, Markovic L, Joshi A, Hardinge K, Murphy J, Wingstrand H
Department of Orthopaedics, Lund University Hospital, Sweden.
J Bone Joint Surg Br. 1998 May;80(3):377-81. doi: 10.1302/0301-620x.80b3.8455.
We analysed in-vivo migration and wear over a long period of all-polyethylene acetabular cups which had not been affected by mechanical loosening. The selection criteria of regular radiological follow-up, good clinical outcome (Charnley score of 5 or 6), continued walking without crutches and no radiological signs of loosening of the acetabular cups were fulfilled by 25 Charnley total hip arthroplasties. Mean migration, measured by the Nunn method, was 0.6 mm in the medial and 0.2 mm in the cranial direction. The mean yearly rate of wear was 0.05 mm and 0.04 mm, with six and two cups having no detectable wear, as measured by the Livermore and Charnley-Cupic methods, respectively. The maximal detected wear was 3.7 mm. There were no changes in the rate of wear with time. Computerised Ein Bild Röntgen Analyse (single-image radiological analysis) measurements of 20 hips indicated plastic deformation of the cups. We conclude that long-term successful cups do not migrate and have a very low rate of wear which was not affected by ageing of the polyethylene. There was no evidence that polyethylene wear alone caused mechanical loosening of the cup but high rates of wear seem to have an adverse prognostic value in terms of the long-term survival of the prosthesis.
我们分析了长期未受机械性松动影响的全聚乙烯髋臼杯的体内移位和磨损情况。25例Charnley全髋关节置换术符合定期放射学随访、良好临床结果（Charnley评分为5或6）、持续不用拐杖行走且髋臼杯无放射学松动迹象的选择标准。采用Nunn方法测量，平均内侧移位为0.6mm，头侧移位为0.2mm。采用Livermore方法和Charnley-Cupic方法测量，平均年磨损率分别为0.05mm和0.04mm，分别有6个和2个髋臼杯未检测到磨损。最大检测到的磨损为3.7mm。磨损率未随时间变化。对20个髋关节进行的计算机化单图像X线分析测量显示髋臼杯存在塑性变形。我们得出结论，长期成功的髋臼杯不会移位，磨损率极低，且不受聚乙烯老化的影响。没有证据表明单纯的聚乙烯磨损会导致髋臼杯的机械性松动，但高磨损率似乎对假体的长期存活具有不良预后价值。
