PURPOSE The purpose of the study was to investigate the biomechanics of walking and of the knee joint in the acute phase of ACL injury. METHODS We examined 18 patients with acute ACL injuries and 20 healthy adults as controls. The biomechanics of the knee joint and of walking was assessed by 5 inertial sensors fixed with special cuffs to the lower back, the lower third of the thigh, and the lower third of the shank of the right and left legs. The movements and temporal characteristics were recorded while the subject was walking 10 m at a comfortable pace. Based on the results of examination, the patients were divided into two groups: with severe function impairment (6 patients) and with moderate function impairment (12 patients). RESULTS It was found that in the first days post-trauma, not only the knee function was reduced, but the function of the entire lower limb as well. This led to a functional asymmetry. The kinematics of movements in the joints changed in accordance with slower walking. The walking became not only slower, but it was also associated with a decreased impact load in the weight acceptance phase. At later dates, the functional impairments were less pronounced. The total range of flexion motion did not exceed 20 degrees in the first group and 55 degrees in the second one. The injured joint developed functional immobilization within the first days post-injury. This was a guarding response by additional muscle strain to prevent unusual and limit physiological movements in the knee joint. The movements in the knee joint while walking were of small amplitude, rocking, and occurred only under load. The amplitude of the main flexion in the swing phase was reduced. CONCLUSION The stage of an ACL injury should be assessed not only based on the time post-trauma, but also taking account of the functional parameter-the knee range of flexion while walking. According to our findings, the only factor that had influenced the functional condition of the KJ was the duration of joint immobilization after trauma.

中文翻译：

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急性期前交叉韧带撕裂患者的膝关节功能和步行生物力学。

目的本研究的目的是研究在ACL损伤急性期中行走和膝关节的生物力学。方法我们检查了18例急性ACL损伤患者和20例健康成人作为对照。膝关节和步行的生物力学通过5个惯性传感器进行评估，这些传感器配有特殊的袖套，固定在右腿和左腿的下背部，大腿下部三分之一和小腿下部三分之一。记录对象以舒适步伐行走10 m时的运动和时间特征。根据检查结果，将患者分为两组：严重功能障碍（6例）和中度功能障碍（12例）。结果发现在创伤后的第一天，不仅膝关节功能下降，但整个下肢的功能也是如此。这导致功能不对称。关节运动的运动学随着慢速行走而改变。行走不仅变慢，而且还与重量接受阶段的冲击负荷降低有关。在以后的日子里，功能障碍并不那么明显。第一组屈曲运动的总范围不超过20度，第二组屈曲运动的总范围不超过55度。受伤的关节在受伤后的头几天就发生了功能性固定。这是附加的肌肉拉伤的保护性反应，以防止异常并限制膝关节的生理运动。行走时膝关节的运动幅度小，摇摆，并且仅在负重下发生。摆动阶段的主屈曲幅度减小。结论ACL损伤的阶段不仅应根据创伤后的时间进行评估，还应考虑功能参数-步行时屈膝的范围。根据我们的发现，影响KJ功能状态的唯一因素是创伤后关节固定的持续时间。