BACKGROUND Atypical knee joint biomechanics after anterior cruciate ligament reconstruction (ACLR) are common. It is, however, unclear whether knee robustness (ability to tolerate perturbation and maintain joint configuration) and whole body movement strategies are compromised after ACLR. PURPOSE To investigate landing control after ACLR with regard to dynamic knee robustness and whole body movement strategies during sports-mimicking side hops, and to evaluate functional performance of hop tests and knee strength. STUDY DESIGN Controlled laboratory study. METHODS An 8-camera motion capture system and 2 synchronized force plates were used to calculate joint angles and moments during standardized rebound side-hop landings performed by 32 individuals with an ACL-reconstructed knee (ACLR group; median, 16.0 months after reconstruction with hamstring tendon graft [interquartile range, 35.2 months]) and 32 matched asymptomatic controls (CTRL). Dynamic knee robustness was quantified using a finite helical axis approach, providing discrete values quantifying divergence of knee joint movements from flexion-extension (higher relative frontal and/or transverse plane motion equaled lower robustness) during momentary helical rotation intervals of 10°. Multivariate analyses of movement strategies included trunk, hip, and knee angles at initial contact and during landing and hip and knee peak moments during landing, comparing ACLR and CTRL, as well as legs within groups. RESULTS Knee robustness was lower for the first 10° motion interval after initial contact and then successively stabilized for both groups and legs. When landing with the injured leg, the ACLR group, as compared with the contralateral leg and/or CTRL, demonstrated significantly greater flexion of the trunk, hip, and knee; greater hip flexion moment; less knee flexion moment; and smaller angle but greater moment of knee internal rotation. The ACLR group also had lower but acceptable hop and strength performances (ratios to noninjured leg >90%) except for knee flexion strength (12% deficit). CONCLUSION Knee robustness was not affected by ACLR during side-hop landings, but alterations in movement strategies were seen for the trunk, hip, and knee, as well as long-term deficits in knee flexion strength. CLINICAL RELEVANCE Knee robustness is lowest immediately after landing for both the ACLR group and the CTRL and should be targeted in training to reduce knee injury risk. Assessment of movement strategies during side-hop landings after ACLR should consider a whole body approach.

中文翻译：

---

具有前交叉韧带重建膝关节的个体显示出非典型的全身运动策略，但在侧跳着陆过程中正常的膝关节健壮性：有限的螺旋轴分析。

背景技术前十字韧带重建（ACLR）后膝关节的非典型生物力学很普遍。然而，ACLR后膝关节的健壮性（耐受摄动和维持关节形态的能力）和全身运动策略是否受到损害尚不清楚。目的研究模拟运动性侧跳过程中ACLR后的动态膝关节健壮性和全身运动策略的着陆控制，并评估跳步测试的功能性能和膝盖力量。研究设计受控的实验室研究。方法采用8台摄像机运动捕获系统和2个同步测力板来计算由32名ACL重建膝盖的个体在进行标准化反弹侧跳着陆时的关节角度和力矩（ACLR组；中位数为16岁）。腿筋腱移植重建后0个月（四分位间距，35.2个月）和32个匹配的无症状对照（CTRL）。动态膝关节健壮性使用有限螺旋轴方法进行量化，提供离散值，用于量化瞬时螺旋旋转间隔为10°时膝关节运动与屈伸运动（较高的相对额骨和/或横向平面运动等于较低的健壮性）之间的差异。运动策略的多变量分析包括初次接触时和着陆时的躯干，髋部和膝盖角度，以及着陆期间的髋部和膝盖峰值时刻，比较ACLR和CTRL以及组内的腿。结果在最初接触后的第一个10°运动间隔中，膝盖的健壮性较低，然后两组和腿部均逐渐稳定。当腿受伤着陆时，与对侧腿和/或CTRL相比，ACLR组的躯干，臀部和膝盖的屈曲明显更大；更大的髋关节屈曲力矩；更少的膝盖屈曲力矩；角度较小，但膝关节内部旋转力矩较大。ACLR组除了膝盖屈曲强度（不足12％）外，还具有较低但可以接受的跳跃和力量表现（对未受伤腿的比率> 90％）。结论侧跳着陆期间ACLR不会影响膝关节的健壮性，但躯干，臀部和膝盖的运动策略会发生变化，并且膝关节屈曲强度会长期下降。临床相关性对于ACLR组和CTRL，降落后的膝关节健壮性最低，并且应该以减少膝部受伤风险的训练为目标。