Kaplan Jonathan T, Ramsay John W, Cameron Sarah E, Seymore Kayla D, Brehler Michael, Thawait Gaurav K, Zbijewski Wojciech B, Siewerdsen Jeffrey H, Brown Tyler N
Combat Capabilities Development Command Soldier Center, Natick, Massachusetts, USA.
Booz Allen Hamilton, Washington, DC, USA.
Am J Sports Med. 2020 May;48(6):1389-1397. doi: 10.1177/0363546520911608. Epub 2020 Apr 7.
Anterior cruciate ligament (ACL) injury is a military occupational hazard that may be attributed to an individual's knee biomechanics and joint anatomy. This study sought to determine if greater flexion when landing with load resulted in knee biomechanics thought to decrease ACL injury risk and whether knee biomechanics during landing relate to knee anatomic metrics.
Anatomic metrics regarding the slope and concavity of the tibial plateau will exhibit a significant relation to the increased anterior shear force on the knee and decreased knee flexion posture during landing with body-borne load.
Descriptive laboratory study.
Twenty male military personnel completed a drop landing task with 3 load conditions: light (~6 kg), medium (15% body weight), and heavy (30% body weight). Participants were divided into groups based on knee flexion exhibited when landing with the heavy load (high- and low-Δflexion). Tibial slopes and depth were measured on weightbearing volumetric images of the knee obtained with a prototype cone beam computed tomography system. Knee biomechanics were submitted to a linear mixed model to evaluate the effect of landing group and load, with the anatomic metrics considered covariates.
Load increased peak proximal anterior tibial shear force ( = .034), knee flexion angle ( = .024), and moment ( = .001) during landing. Only the high flexion group increased knee flexion ( < .001) during weighted landings with medium and heavy loads. The low flexion group used greater knee abduction angle ( = .030) and peak proximal anterior tibial shear force ( = .034) when landing with load. Anatomic metrics did not differ between groups, but ratio of medial-to-lateral tibial slope and medial tibial depth predicted peak proximal anterior tibial shear force ( = .009) and knee flexion ( = .034) during landing, respectively.
Increasing knee flexion is an attainable strategy to mitigate risk of ACL injury, but certain individuals may be predisposed to knee forces and biomechanics that load the ACL during weighted landings.
The ability to screen individuals for anatomic metrics that predict knee flexion may identify soldiers and athletes who require additional training to mitigate the risk of lower extremity injury.
前交叉韧带（ACL）损伤是一种军事职业风险，可能归因于个体的膝关节生物力学和关节解剖结构。本研究旨在确定负重着陆时更大的屈曲角度是否会产生被认为可降低ACL损伤风险的膝关节生物力学，以及着陆时的膝关节生物力学是否与膝关节解剖学指标相关。
关于胫骨平台坡度和凹陷度的解剖学指标将与着陆时膝关节上增加的前剪切力以及负重着陆时膝关节屈曲姿势的降低存在显著关系。
描述性实验室研究。
20名男性军事人员在3种负重条件下完成了下蹲着陆任务：轻负重（约6千克）、中等负重（体重的15%）和重负重（体重的30%）。参与者根据重负重着陆时表现出的膝关节屈曲情况分为两组（高屈曲度组和低屈曲度组）。使用原型锥形束计算机断层扫描系统获取膝关节负重容积图像，测量胫骨坡度和深度。将膝关节生物力学数据纳入线性混合模型，以评估着陆组和负重的影响，将解剖学指标视为协变量。
负重增加了着陆时近端胫骨前剪切力峰值（P = 0.034）、膝关节屈曲角度（P = 0.024）和力矩（P = 0.001）。只有高屈曲度组在中等和重负重的加权着陆过程中增加了膝关节屈曲（P < 0.001）。低屈曲度组在负重着陆时使用了更大的膝关节外展角度（P = 0.030）和近端胫骨前剪切力峰值（P = 0.034）。两组之间的解剖学指标没有差异，但内侧与外侧胫骨坡度之比和内侧胫骨深度分别预测了着陆时近端胫骨前剪切力峰值（P = 0.009）和膝关节屈曲（P = 0.034）。
增加膝关节屈曲是减轻ACL损伤风险的一种可行策略，但某些个体可能易受膝关节受力和生物力学影响，在负重着陆时使ACL承受负荷。
能够筛选出预测膝关节屈曲的解剖学指标的个体，这可能有助于识别那些需要额外训练以降低下肢损伤风险的士兵和运动员。
