Osternig L R, Ferber R, Mercer J, Davis H
Department of Exercise and Movement Science, University of Oregon, Eugene 97403, USA.
Eur J Appl Physiol. 2000 Sep;83(1):71-6. doi: 10.1007/s004210000249.
It has been postulated that the adaptations of lower extremity function exhibited by anterior cruciate ligament (ACL) deficient and post-ACL surgical patients represent early accommodations to the loss of ACL function after injury so that excessive anterior displacement of the tibia is prevented. Prior studies have suggested that compensation patterns in ACL deficient and post-ACL surgical subjects may affect joint moments of the knee as well as the hip. However, the variance in knee and hip forces between ACL deficient, post-surgical ACL and uninjured groups has not been clearly elucidated. The purpose of this study was to assess hip:knee extensor torque ratios relative to anterior tibia shear in pre-surgical-ACL deficient, post-surgical and uninjured subjects. Measurements of hip and knee joint moments and anterior tibia shear were recorded from 45 injured and uninjured subjects (21 men, 24 women) during lower extremity, variable resistance exercise. Anterior tibia shear was computed by decomposing joint moments and reaction forces according to a model derived from cadaver knee dissections and radiography, in combination, to estimate the tibio-femoral compressive and shear forces generated by the patellar tendon at various angles throughout the knee joint range. Three groups of subjects were studied: recently injured ACL deficient pre-surgical subjects who were scheduled for immediate surgery (PRE; n = 15); postsurgical subjects who had undergone ACL reconstructive surgery at least 1 year prior to testing (POST; n = 15); and uninjured controls (CON; n = 15). All PRE and POST subjects had a normal contralateral limb. Tests were conducted under six conditions: 1 and 1.5 Hz cadence and maximal speed at 33% and 50% one repetition maximum resistance. The results revealed that the hip:knee ratios were significantly greater for the post-ACL surgical group than the PRE and CON groups (P<0.01; P<0.03). There were significant negative correlations between the hip extensor:knee extensor torque ratios and maximal anterior tibia shear across all groups. The hip:knee extensor torque ratio increased with decreased anterior tibia shear in all groups with significant correlations ranging from -0.55 to -0.88 (P<0.01) for the injured limbs of PRE and POST groups, and -0.64 to -0.78; (P<0.01) for the CON group. The highest overall correlations were found for the post-surgical subjects. The results revealed that anterior tibia shear declined significantly with speed (P<0.01) in all groups. However, the converse was true for the hip:knee extensor torque ratio across speeds. The ratio increased significantly with speed (P<0.001) for all groups at the 33% and 50% resistances. The results suggest (1) that post-ACL surgical subjects appear to accommodate to ACL substitution by using hip extensors to a significantly greater extent than the uninjured controls in closed-chain lower extremity exercise; (2) that the hip:knee extensor torque ratio is significantly related to the magnitude of anterior tibia shear; and (3) that the anterior tibia shear is significantly reduced as speed increases in closed-chain lower extremity exercise.
据推测，前交叉韧带（ACL）缺失和ACL手术后的患者所表现出的下肢功能适应性，代表了受伤后对ACL功能丧失的早期适应，从而防止胫骨过度向前移位。先前的研究表明，ACL缺失和ACL手术后受试者的代偿模式可能会影响膝关节以及髋关节的关节力矩。然而，ACL缺失组、ACL手术后组和未受伤组之间膝关节和髋关节受力的差异尚未明确阐明。本研究的目的是评估手术前ACL缺失、手术后和未受伤受试者相对于胫骨前剪切力的髋：膝伸肌扭矩比。在下肢可变阻力运动期间，记录了45名受伤和未受伤受试者（21名男性，24名女性）的髋关节和膝关节力矩以及胫骨前剪切力测量值。胫骨前剪切力是根据尸体膝关节解剖和X射线摄影得出的模型，通过分解关节力矩和反作用力来计算的，以估计髌腱在整个膝关节范围内不同角度产生的胫股压缩力和剪切力。研究了三组受试者：计划立即手术的近期受伤的手术前ACL缺失受试者（术前组；n = 15）；测试前至少1年接受过ACL重建手术的术后受试者（术后组；n = 15）；以及未受伤的对照组（对照组；n = 15）。所有术前组和术后组受试者对侧肢体均正常。测试在六种条件下进行：节奏为1和1.5 Hz，最大速度为33%和50%的一次重复最大值阻力。结果显示，ACL手术后组的髋：膝比显著高于术前组和对照组（P<0.01；P<0.03）。所有组的髋伸肌：膝伸肌扭矩比与最大胫骨前剪切力之间存在显著负相关。在所有组中，随着胫骨前剪切力降低，髋：膝伸肌扭矩比增加，术前组和术后组受伤肢体的显著相关性范围为-0.55至-0.88（P<0.01），对照组为-0.64至-0.78（P<0.01）。术后受试者的总体相关性最高。结果显示，所有组中胫骨前剪切力均随速度显著下降（P<0.01）。然而，跨速度的髋：膝伸肌扭矩比情况则相反。在33%和50%阻力下，所有组的该比值均随速度显著增加（P<0.001）。结果表明：（1）在闭链下肢运动中，ACL手术后的受试者似乎比未受伤的对照组更大程度地利用髋伸肌来适应ACL替代；（2）髋：膝伸肌扭矩比与胫骨前剪切力的大小显著相关；（3）在闭链下肢运动中，随着速度增加，胫骨前剪切力显著降低。
