Songy Chad E, Couch Cory G, Siegel Eric R, Kee James R, Ahmadi Shahryar
University of Arkansas of for Medical Sciences, Department of Orthopaedic Surgery, Little Rock, AR, United States.
University of Arkansas of for Medical Sciences, Department of Biostatistics, Little Rock, AR, United States.
Clin Biomech (Bristol). 2018 Dec;60:89-94. doi: 10.1016/j.clinbiomech.2018.10.005. Epub 2018 Oct 4.
The purpose of this study is to investigate how different diameters of radial head replacement affect posterolateral translation with a valgus and supination force. We hypothesized that there would be less posterolateral rotatory translation with larger implant diameter.
Eleven cadaveric arms were stressed at 30 and 60° of flexion with a consistent supination and valgus stress force under five conditions: native radial head, radial head excision, and with 3 sizes of radial head prosthesis. Displacement of the radial head posteriorly in relation to the capitellum on radiographs was measured. Displacement was expressed as a percentage relative to the average of the maximum and minimum native radial head diameters.
The native radial heads had average minimum and maximum diameters of 23.3 mm and 25.2 mm, respectively. The angle of testing did not significantly change translation of the radial head. There was increased posterior translation relative to native head as the radial head sizes decreased from 24 mm to 20 mm and with excision of the radial head. Compared to the native head, the differences in displacement were statistically significant for the 20 mm radial head, but not for the 22 mm or 24 mm replacements. Radial head translation significantly increased after radial head excision.
This cadaveric study illustrates that patients treated with radial head excision and radial head prosthesis with undersized diameters have increased posterior translation with a valgus and supination stress. The larger the radial head prosthesis (closer to native radial head), the more closely it approximated the amount of translation of the native radial head.
本研究旨在探讨不同直径的桡骨头置换物在施加外翻和旋后力时如何影响后外侧平移。我们假设植入物直径越大，后外侧旋转平移越少。
在五种情况下，对11具尸体手臂在30°和60°屈曲位施加持续的旋后和外翻应力：完整桡骨头、桡骨头切除以及三种尺寸的桡骨头假体。测量X线片上桡骨头相对于肱骨小头向后的移位。移位以相对于完整桡骨头最大和最小直径平均值的百分比表示。
完整桡骨头的平均最小直径和最大直径分别为23.3mm和25.2mm。测试角度对桡骨头的平移没有显著影响。随着桡骨头尺寸从24mm减小到20mm以及桡骨头切除，相对于完整桡骨头，后向平移增加。与完整桡骨头相比，20mm桡骨头假体的移位差异具有统计学意义，而22mm和24mm置换物的移位差异无统计学意义。桡骨头切除后，桡骨头平移显著增加。
这项尸体研究表明，接受桡骨头切除和使用直径过小的桡骨头假体治疗的患者，在施加外翻和旋后应力时后向平移增加。桡骨头假体越大（越接近完整桡骨头），其平移量越接近完整桡骨头的平移量。
