摘要

背景：

前交叉韧带重建后，步态期间的生物力学不对称非常普遍、持续，并与创伤后膝关节骨关节炎有关。股四头肌力量是与术前步态不对称和术后功能相关的重要临床指标，也是恢复运动清除的主要标准。股四头肌力量对称性与步态生物力学相关的证据仅限于恢复运动训练前的术前和早期康复时间点。

目的/假设：

确定运动员前交叉韧带重建后恢复运动训练后等长股四头肌力量对称性与步态生物力学之间的关系。我们假设，随着股四头肌力量对称性的增加，运动员将表现出更对称的膝关节生物力学，包括步态期间的胫股关节负荷。

研究设计：

横断面研究。

方法：

参加ACL-SPORTS的79名运动员中有10名在完成术后康复和7次恢复运动训练（ACLR后1.2±0.100个月）后成为本研究的参与者。所有参与者都使用机电测功机完成了生物力学步行步态分析和等长股四头肌强度评估。股四头肌力量使用肢体对称指数（受累肢体值/未受累肢体值 x 0%）计算。感兴趣的生物力学变量包括：峰值膝关节屈曲角（PKFA），峰值膝关节内伸力矩，体重接受和站位中期的矢状面膝关节偏移，PKFA处的股四头肌肌力和峰值内侧间室接触力。利用Spearman's rho（ρ）相关系数分别确定股四头肌力量肢体对称指数与各生物力学变量的关系;alpha 设置为 05.<>。

结果：

在76名参与者中，27名（35%）表现出股四头肌力量不对称，定义为股四头肌力量对称性<90%（n = 23）或>110%（n = 4）（QI范围：56.9%-131.7%）。对于感兴趣的生物力学变量，67%的膝关节峰值屈曲角度不对称，重量接受和中期的膝关节偏移分别为68%和83%，膝关节内伸展力矩为74%，内侧间室接触力为57%，股四头肌肌力为74%。恢复运动训练后，股四头肌力量指数与肢体对称指数之间没有显著相关性（p>0.129）。

结论：

在ACL重建后完成恢复运动训练的患者中，随后的股四头肌力量对称性与步态生物力学的持续不对称性无关。在达到股四头肌力量阈值后，仅恢复力量可能无法改善步态不对称，目前的临床干预和恢复运动训练可能无法充分针对步态。

Abstract

Background: After anterior cruciate ligament (ACL) reconstruction (ACLR), biomechanical asymmetries during gait are highly prevalent, persistent, and linked to posttraumatic knee osteoarthritis. Quadriceps strength is an important clinical measure associated with preoperative gait asymmetries and postoperative function and is a primary criterion for return-to-sport clearance. Evidence relating symmetry in quadriceps strength with gait biomechanics is limited to preoperative and early rehabilitation time points before return-to-sport training.

Purpose/hypothesis: The purpose was to determine the relationship between symmetry in isometric quadriceps strength and gait biomechanics after return-to-sport training in athletes after ACLR. We hypothesized that as quadriceps strength symmetry increases, athletes will demonstrate more symmetric knee joint biomechanics, including tibiofemoral joint loading during gait.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: Of 79 athletes enrolled in the ACL-SPORTS Trial, 76 were participants in this study after completing postoperative rehabilitation and 10 return-to-sport training sessions (mean ± SD, 7.1 ± 2.0 months after ACLR). All participants completed biomechanical walking gait analysis and isometric quadriceps strength assessment using an electromechanical dynamometer. Quadriceps strength was calculated using a limb symmetry index (involved limb value / uninvolved limb value × 100). The biomechanical variables of interest included peak knee flexion angle, peak knee internal extension moment, sagittal plane knee excursion at weight acceptance and midstance, quadriceps muscle force at peak knee flexion angle, and peak medial compartment contact force. Spearman rank correlation (ρ) coefficients were used to determine the relationship between limb symmetry indexes in quadriceps strength and each biomechanical variable; alpha was set to .05.

Results: Of the 76 participants, 27 (35%) demonstrated asymmetries in quadriceps strength, defined by quadriceps strength symmetry <90% (n = 23) or >110% (n = 4) (range, 56.9%-131.7%). For the biomechanical variables of interest, 67% demonstrated asymmetry in peak knee flexion angle; 68% and 83% in knee excursion during weight acceptance and midstance, respectively; 74% in internal peak knee extension moment; 57% in medial compartment contact force; and 74% in quadriceps muscle force. There were no significant correlations between quadriceps strength index and limb symmetry indexes for any biomechanical variable after return-to-sport training (P > .129).

Conclusion: Among those who completed return-to-sport training after ACLR, subsequent quadriceps strength symmetry was not correlated with the persistent asymmetries in gait biomechanics. After a threshold of quadriceps strength is reached, restoring strength alone may not ameliorate gait asymmetries, and current clinical interventions and return-to-sport training may not adequately target gait. 

From：

Am J Sports Med. 2021 Feb;49(2):417-425.

 doi: 10.1177/0363546520980079