Thambyah Ashvin, Goh James C H, De Shamal Das
Department of Orthopaedic Surgery, National University of Singapore.
Med Eng Phys. 2005 May;27(4):329-35. doi: 10.1016/j.medengphy.2004.09.002.
The contact stresses in the knee that arise from activities involving deep flexion have not been given due consideration in view of social and cultural practice amongst many Asians that frequently cause the engagement of these activities. Excessively large stresses (>25 MPa) can cause cartilage damage and may be the precursor to the development of degenerative disease of the joint. In this study, forces in the knee derived from previous studies of human walking and squatting were applied to five cadaver knees that underwent quasi-static mechanical testing. This was conducted using a materials-testing machine and a custom-made apparatus that allowed secure and consistent loading of the knee specimen in flexion beyond 120 degrees. A thin-film electronic pressure transducer was inserted into the cadaver tibiofemoral joint space to measure force and area. Throughout the various positions simulating specific phases of walking, it was found that stresses peaked to 14 MPa (standard deviation was 2.5 MPa). In deep flexion, the peak stresses were significantly larger by over 80%, reaching the damage limits of cartilage. The results from this biomechanical study suggest that the adequacy of articular cartilage to support loads in the knee joint during deep flexion may be questionable.
鉴于许多亚洲人的社会文化习惯经常导致进行涉及深度屈曲的活动，因而在这些活动中产生的膝关节接触应力尚未得到应有的重视。过大的应力（>25兆帕）会导致软骨损伤，可能是关节退行性疾病发展的先兆。在本研究中，将先前对人类行走和下蹲研究得出的膝关节受力情况应用于五个进行准静态力学测试的尸体膝关节。这是通过一台材料试验机和一个定制装置进行的，该装置能确保在膝关节标本屈曲超过120度时安全且持续地加载。将一个薄膜电子压力传感器插入尸体胫股关节间隙以测量力和面积。在模拟行走特定阶段的各个位置上，发现应力峰值达到14兆帕（标准差为2.5兆帕）。在深度屈曲时，峰值应力显著增大超过80%，达到软骨的损伤极限。这项生物力学研究的结果表明，关节软骨在深度屈曲时支撑膝关节负荷的能力可能存在疑问。
