附录2 资料性附录 本附录内容,注册申请人在产品研发时依据产品特征予以关注。 一、关节面接触面积和接触应力分布研究 全膝关节假体关节面的磨损与接触应力、接触面积相关,通过测试接触应力、接触面积有助于预测假体关节面的磨损性能[1-2],从而为假体关节面设计改进以及磨损试验最差情况的选择提供依据。 对于胫股关节面,建议在屈曲角为0°、15°、30°、60°、90°和最大屈曲角度时分析或者测试接触应力和接触面积,并在90°和最大屈曲角处时带有0°旋转和15°内旋/外旋进行试验,对于内旋外旋活动度具有一定限制的假体,如髁限制型假体,内旋外旋角度可能达不到15°,需根据假体轴向旋转活动度选择适宜的角度进行试验。对于活动平台假体,应对所有的接触面(股骨-胫骨衬垫、胫骨衬垫-胫骨托)进行接触面积和接触应力的测试。上述接触应力和接触面积分布的测试可参照ASTM F2083的方法进行分析或试验。 采用体外试验方法测试胫股关节面接触应力和接触面积时,将股骨髁和胫骨部件固定在与假体匹配的模拟骨或金属夹具上,胫骨部件夹具可允许具有一定的前后方向、轴向旋转和内翻外翻自由度,当施加载荷时,胫骨部件可以微调到达平衡位置。将夹具固定在力学试验机上,使加载轴线通过膝关节假体股骨髁间窝中心或者模拟膝关节假体生产企业推荐的力线对线、倾角(如胫骨部件后倾角)要求。对于电子压力测试装置(如K-scan),需要在试验前按照设备要求进行传感器校准和计量,对于压敏薄膜,需要根据试验选择的载荷水平选取相适应的压力级别薄膜进行测试。将电子压力测试装置的传感器或压敏薄膜置于关节面之间,预施加载荷观察接触区域是否完全在传感器或压敏薄膜边界内,在不同的屈曲角度下施加不同的载荷[3-6],记录相应的关节面的接触应力和接触面积。上述试验过程仅描述了屈曲角度和载荷,为模拟体内股骨髁和胫骨部件的相对位置,可进一步考虑在不同屈曲角度下股骨外旋(或胫骨内旋)、前后位移和内翻外翻角度对接触应力和接触面积的影响,设置相应的试验条件测试接触应力和接触面积分布。此外,除电子压力测试装置和压敏薄膜外,也可采用超声测量装置测试膝关节假体关节面的接触应力和接触面积分布[7]。 对于髌股关节面,建议在屈曲角为15°、45°、90°和最大屈曲角度时在相应的载荷下测试髌股关节面的接触应力和接触面积,可参照ASTM
F1672的方法或文献[8-13]中描述的方法进行试验或有限元分析,需描述具体的测试方法(包括股骨与髌骨的相对位置、加载载荷、固定夹具等)、试验设备和材料、测试结果。 参考文献 [1] Rostoker W, Galante J.
O. Contact pressure dependence of wear rates of ultra high molecular weight
polyethylene. J Biomed Mater Res, 1979, 13: 957. [2] Abdellatif Abdelgaied,
Claire L Brockett, Feng Liu, Louise M Jennings, Zhongmin Jin and John Fisher.
The effect of insert conformity and material on total knee replacement wear.
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of
Engineering in Medicine, 2014, 228: 98-106. [3] Szivek, J. A.,
Cutignola, L., Volz, R. G. Tibiofemoral Contact Stress and Stress Distribution
Evaluation of Total Knee Arthroplasties. J. Arthroplasty, Vol 10, No. 4, 1995,
pp. 480–491. [4] Harris, M. L., Morberg,
P., Bruce, W. J. M., Walsh, W. R. An Improved Method for Measuring Tibiofemoral
Contact Areas in Total Knee Arthroplasty: A Comparison of K-Scan Sensor and
Fuji Film. Journal of Biomechanics, Vol 32, 1999, pp. 951-958. [5] DeMarco, A. L., Rust, D.
A., Bachus, K. N. Measuring Contact Pressure and Contact Area in Orthopedic
Applications: Fuji Film vs Tekscan. Orthopedic Research Society, March 12-15,
2000, Orlando, FL, p. 518. [6] Otto, J. K., Brown, T.
D., Heiner, A. D., Callaghan, J. J. Heredity Integral Drift Compensation in
Piezoresistive Contact Stress Sensors. Orthopedic Research Society, February
1-4, 1999, Anaheim, CA, p. 957. [7] Zdero R., Fenton P. V.,
Rudan J., Bryant J. T. Fuji film and ultrasound measurement of total knee
arthroplasty contact areas. The Journal of Arthroplasty, 2001, 16(3): 367-375. [8] McNamara, J. L.,
Collier, J.P., Mayor, M.B., and Jensen, R. E. A Comparison of Contact Pressures
in Tibial and Patellar Total Knee Components Before and After Service In-Vivo.
Clin. Orthop. Rel. Res., No. 299, 1994, pp. 104–113. [9] Morra, E. A., and
Greenwald, A. Seth. Patello-Femoral Replacement Polymer Stress During Daily
Activities: A Finite Element Study. AAOS 2006, Orthopaedic Research
Laboratories, Cleveland, OH: http://orl-inc.com. [10] Reilly, D. T., and
Martens, M. Experimental Analysis of the Quadriceps Muscle Force and Patello-Femoral
Joint Reaction Force for Various Activities. Acta Orthop Scand, Vol 43, 1972,
pp. 126–137. [11] Mathews, L. S.,
Sonstegard, D. A., and Henke, J. A., Load Bearing Characteristics of the
Patello-Femoral Joint. Acta Orthop Scand, Vol 48, 1977, pp. 511–516. [12] Sharma, A., Leszko, F.,
Komistek, R. D., Scudery, G. R., Cates, H. E., and Liu, F. In Vivo
Patellafemoral Forces in High Flexion Total Knee Arthroplasty. Journal of
Biomechanics, Vol 41, 2008, pp. 642–648. [13] Mason, J., Leszko, F.,
Johnson, T., and Komistek, R. D. Patellofemoral Joint Forces. Journal of
Biomechanics, Vol 41, 2008, pp.2337–2348.
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