Schwartz O, Aunallah J, Levitin M, Mendes D G
Forum for Excellence in Orthopaedic Surgery, Center for Implant Surgery Bnai Zion Medical Center, Technion Israel Institute of Technology, Haifa, Israel.
Acta Orthop Belg. 2002 Oct;68(4):362-9.
The so-called "papillon" pattern of polyethylene wear of 17 patellar components from 5 Kinematic and 12 Total Condylar prostheses, retrieved after an average of 80 months in situ, was studied. The primary diagnosis was osteoarthritis in all cases. Four modes of damage were observed: polishing in 13 cases, delamination in 12, cold flow in 6 and scratching in 3. The median total area of polyethylene damage was 76.5% for polishing, 70.6% for delamination, 35.3% for cold flow and 17.6% for scratching. The importance of the conformity of the Kinematic patellar component in order to decrease contact stresses was confirmed. The average contact stresses on the nonconforming total Condylar patellar component (12.9 kgf/mm2), were significantly higher (p < 0.002) than the average contact stresses on the conforming Kinematic patellar component (2.9 kgf/mm2). The area of wear was smaller for the nonconforming Total Condylar (357.2 mm2) than for the conforming Kinematic patella (439.2 mm2). This difference, however, is not statistically significant. The average weight of the patients with a Kinematic Knee (74.5 kg) was higher than that of patients with a Total Condylar knee (66 kg), but the difference was not significant. The high incidence of significant wear of the patellar components indicates that a basic deficiency is present in the design of patellar implants, and calls for the improvement of two mechanical features: adequate thickness of the polyethylene implant and conforming articulating surfaces.
研究了从5个动力学假体和12个全髁假体中取出的17个髌骨组件的聚乙烯磨损的所谓“蝴蝶”模式，这些假体平均在位80个月后被取出。所有病例的主要诊断均为骨关节炎。观察到四种损伤模式：13例出现抛光，12例出现分层，6例出现冷流，3例出现刮擦。聚乙烯损伤的中位总面积，抛光为76.5%，分层为70.6%，冷流为35.3%，刮擦为17.6%。证实了动力学髌骨组件的贴合度对于降低接触应力的重要性。不符合要求的全髁髌骨组件上的平均接触应力（12.9千克力/平方毫米）显著高于（p < 0.002）符合要求的动力学髌骨组件上的平均接触应力（2.9千克力/平方毫米）。不符合要求的全髁髌骨组件的磨损面积（357.2平方毫米）小于符合要求的动力学髌骨组件的磨损面积（439.2平方毫米）。然而，这种差异无统计学意义。使用动力学膝关节的患者的平均体重（74.5千克）高于使用全髁膝关节的患者的平均体重（66千克），但差异不显著。髌骨组件显著磨损的高发生率表明髌骨植入物的设计存在基本缺陷，需要改进两个机械特性：聚乙烯植入物的足够厚度和贴合的关节表面。
