Michael W. Krzyzewski Human Performance Laboratory, Duke University, Durham, NC 27710, USA.
Am J Sports Med. 2012 Dec;40(12):2756-63. doi: 10.1177/0363546512460837. Epub 2012 Oct 3.
Anterior cruciate ligament (ACL) reinjury rates are high in adolescent patients. Knee braces are commonly used after ACL reconstruction to prevent reinjury during return to sports.
Adolescent patients following ACL injury would demonstrate a decreased vertical ground-reaction force, knee extension moment, knee flexion angle, and knee flexion velocity on the surgical limb when compared with the nonsurgical limb during a side-cutting task. A functional knee extension-resistant brace would decrease the limb asymmetries.
Controlled laboratory study.
Twenty-three adolescent patients 6 months after ACL reconstruction were recruited for this study. Three-dimensional kinematic and kinetic data were collected bilaterally (surgical, nonsurgical) during a 35° side-cutting task while the patient was wearing and not wearing a functional knee extension-resistant brace (nonbraced, braced) on the surgical limb.
The surgical limb demonstrated a significant decrease in peak impact vertical ground-reaction force (2.55 body weight [BW] vs 2.8 BW; P < .01), peak propulsion vertical ground-reaction force (2.15 BW vs 2.3 BW; P < .01), peak knee extension moment (0.13 BW × body height [BH] vs 0.17 BW × BH; P < .01), knee flexion angle at peak knee flexion velocity (27.8° vs 30.0°; P = .01), peak knee flexion angle (44.1° vs 48.5°; P < .01), and peak knee flexion velocity (571.3 deg/sec vs 640.1 deg/sec; P < .01) when compared with the nonsurgical limb during both nonbraced and braced conditions. Bracing increased the initial knee flexion velocity (42.4 deg/sec vs -40.2 deg/sec; P = .01) and decreased the initial knee flexion angle on the surgical limb (13.1° vs 15.7°; P < .01). Bracing also affected kinematics of the nonsurgical limb. Bracing did not decrease the asymmetry between surgical and nonsurgical limbs.
Adolescent patients 6 months after ACL reconstruction demonstrated significant kinematic and kinetic asymmetries between the surgical and nonsurgical limbs. The limb asymmetries persisted when the patients were wearing a functional knee brace. There were changes in the surgical knee kinematics with and without bracing, especially near initial ground contact.
The limb asymmetries are of concern with regard to injuring the graft or the contralateral limb when the patients return to sport.
前交叉韧带（ACL）损伤在青少年患者中的发生率很高。ACL 重建后，常使用膝关节支具防止重返运动时再次受伤。
ACL 损伤后的青少年患者在进行侧步运动时，与非手术侧相比，手术侧的垂直地面反作用力、膝关节伸肌力矩、膝关节屈曲角度和膝关节屈曲速度会降低。一种功能性膝关节抗伸展支具会减少肢体不对称。
对照实验室研究。
本研究招募了 23 名 ACL 重建后 6 个月的青少年患者。在患者穿着和不穿功能性膝关节抗伸展支具（非支具、支具）的情况下，双侧（手术侧、非手术侧）采集 35°侧步运动的三维运动学和动力学数据。
手术侧的峰值冲击垂直地面反作用力（2.55 体重[BW]比 2.8 BW；P<.01）、峰值推进垂直地面反作用力（2.15 BW 比 2.3 BW；P<.01）、峰值膝关节伸肌力矩（0.13 BW×身高[BH]比 0.17 BW×BH；P<.01）、膝关节屈曲速度峰值时的膝关节屈曲角度（27.8°比 30.0°；P=.01）、峰值膝关节屈曲角度（44.1°比 48.5°；P<.01）和峰值膝关节屈曲速度（571.3 度/秒比 640.1 度/秒；P<.01）均显著低于非手术侧。在非支具和支具两种情况下，支具都增加了初始膝关节屈曲速度（42.4 度/秒比-40.2 度/秒；P=.01）和减小了手术侧的初始膝关节屈曲角度（13.1°比 15.7°；P<.01）。支具也影响了非手术侧的运动学。支具并不能减少手术侧和非手术侧之间的不对称。
ACL 重建后 6 个月的青少年患者手术侧和非手术侧之间存在明显的运动学和动力学不对称。当患者穿上功能性膝关节支具时，肢体不对称仍然存在。有和没有支具时，手术膝关节的运动学都发生了变化，尤其是在初始地面接触时。
当患者重返运动时，肢体不对称可能会导致移植物或对侧肢体受伤。
