A biomechanical study was conducted on eight cadaveric knees. A 20-mm defect was created in the weight-bearing zone on the medial femoral condyle then filled either with three plugs of 8 mm, or with four plugs of 6 mm, or with 6 plugs of 4 mm diameter. After the preparation of the specimens, each knee was installed on a mechanical test bench (Instron 5566A). A continuous axial compression of 700 N at 10 mm.min-1 was exerted on the joint. A K-scan 4000-type pressure sheet was used to record the contact area (mm2), the mean pressure (MPa), and the maximum pressure (MPa) on the area of interest.
The differences found between the conditions were not statistically significant but showed tendencies. Filling the defect with six plugs of 4 mm restores a larger contact surface compared with the other plugs. The use of 8- and 6-mm grafts lead to a respective increase of 12% and 52% of the mean pressure compared with the 4 mm grafts. This difference was also found for the maximum pressure (36% and 129%). Regardless of the diameter of the plugs used, filling the lesion reduces the mean pressure exerted on the healthy cartilage by 19%.
A trend emerged towards a better restoration of the cartilage surface and a more harmonious distribution of the pressures exerted in favour of the grafts of smaller diameter. A larger study is needed to obtain a statistically significant result.
方法:对8个尸体膝盖进行了生物力学研究。在股骨内侧髁的负重区产生20毫米的缺损,然后用三个8毫米的塞子填充,或有四个6毫米的插头,或6个4毫米直径的插头。标本制备后,将每个膝部安装在机械测试台上(Instron5566A).一个连续的轴向压缩700N在10毫米。min-1施加在关节上。使用K-scan4000型压力表来记录接触面积(mm2),平均压力(MPa),以及感兴趣区域上的最大压力(MPa)。
结果:发现的条件之间的差异没有统计学意义,但显示出趋势。与其他塞子相比,用6个4mm的塞子填充缺陷可恢复更大的接触表面。与4毫米移植物相比,使用8毫米和6毫米移植物分别导致平均压力增加12%和52%。对于最大压力(36%和129%)也发现了这种差异。不管使用的插头的直径如何,填充病变可使施加在健康软骨上的平均压力降低19%。
结论:出现了一种趋势,即更好地恢复软骨表面和更和谐的压力分布,有利于直径较小的移植物。需要更大的研究才能获得统计学上显著的结果。