Komistek Richard D, Dennis Douglas A, Ochoa Jorge A, Haas Brian D, Hammill Curt
Rocky Mountain Musculoskeletal Research Laboratory, Denver, Colorado 80222, USA.
J Bone Joint Surg Am. 2002 Oct;84(10):1836-41. doi: 10.2106/00004623-200210000-00015.
Twenty subjects were analyzed in vivo with use of video fluoroscopy to determine if the femoral head separates from the acetabular component during normal gait and to determine if the amount of separation differs between metal-on-metal and metal-on-polyethylene total hip prostheses.
Ten subjects had been treated with a metal-on-metal total hip arthroplasty and ten, with a metal-on-polyethylene total hip arthroplasty. All of the prostheses were implanted by the same surgeon utilizing the same surgical technique, and all were judged to be clinically successful (a Harris hip score of >90 points). Each subject walked with a normal gait on a level treadmill while under fluoroscopic surveillance. The two-dimensional fluoroscopic videotapes were then converted into three-dimensional images with use of a computer-automated model-fitting technique. Each implant was analyzed at various flexion angles to assess the amount of femoral head sliding.
No femoral head sliding was observed in the subjects with a metal-on-metal implant, whereas all ten subjects with a metal-on-polyethylene implant had sliding that was greater than our threshold value of 0.75 mm. The average amount of femoral head sliding in these subjects was 2.0 mm, and the sliding was observed during the swing phase of gait. The sliding was typically seen medially while the femoral head remained in contact with the acetabular component superolaterally.
Femoral head sliding commonly occurred following traditional metal-on-polyethylene total hip arthroplasty but not after metal-on-metal arthroplasty. These kinematic data may be of value in future hip-simulation studies to better duplicate wear patterns observed in retrieval analyses, assist in the understanding of the lubrication and wear rates of metal-on-metal designs, and facilitate designing of prosthetic components that minimize wear and optimize hip kinematics.
对20名受试者进行了体内视频荧光透视分析，以确定在正常步态期间股骨头是否与髋臼部件分离，并确定金属对金属和金属对聚乙烯全髋关节假体之间的分离量是否存在差异。
10名受试者接受了金属对金属全髋关节置换术，另外10名接受了金属对聚乙烯全髋关节置换术。所有假体均由同一位外科医生采用相同的手术技术植入，且所有假体在临床上均被判定为成功（Harris髋关节评分>90分）。每位受试者在荧光透视监测下在水平跑步机上以正常步态行走。然后，利用计算机自动模型拟合技术将二维荧光透视录像转换为三维图像。在不同的屈曲角度对每个植入物进行分析，以评估股骨头滑动的量。
在接受金属对金属植入物的受试者中未观察到股骨头滑动，而所有10名接受金属对聚乙烯植入物的受试者均出现了大于我们设定的0.75毫米阈值的滑动。这些受试者股骨头滑动的平均量为2.0毫米，且在步态的摆动期观察到了滑动。通常在股骨头与髋臼部件上外侧保持接触的同时，在内侧观察到滑动。
传统的金属对聚乙烯全髋关节置换术后常见股骨头滑动，而金属对金属置换术后则未出现。这些运动学数据可能对未来的髋关节模拟研究有价值，以更好地复制在取出分析中观察到的磨损模式，有助于理解金属对金属设计的润滑和磨损率，并便于设计出能使磨损最小化并优化髋关节运动学的假体部件。
