Williams Glenn N, Buchanan Thomas S, Barrance Peter J, Axe Michael J, Snyder-Mackler Lynn
Center for Biomedical Engineering Research, University of Delaware, Newark, DE 19716, USA.
Am J Sports Med. 2005 Mar;33(3):402-7. doi: 10.1177/0363546504268042.
Quadriceps weakness is common after anterior cruciate ligament injury, especially in those who do not compensate well for the injury ("noncopers"). Both atrophy and activation failure have been demonstrated in this population but have not been directly related to quadriceps weakness.
(1) Quadriceps strength, volumes, and cross-sectional areas of the noncopers would be smaller than those of the contralateral muscles, whereas other muscles would not demonstrate atrophy. (2) Quadriceps muscle activation deficits would be observed. (3) Atrophy and activation failure would account for the quadriceps weakness in these patients.
Cross-sectional study, Level of evidence, 3.
Seventeen noncopers with isolated anterior cruciate ligament injury underwent burst-superimposition strength and activation testing of the quadriceps and magnetic resonance imaging of 12 muscles an average of 2 months after injury. Morphological characteristics was described by digitally reconstructing each muscle from the axial images and calculating muscle volume and peak cross-sectional area.
The quadriceps muscles of the anterior cruciate ligament-deficient limb were significantly weaker (average 25%) than those of the uninjured side; activation failure (8%-10%) was observed for the quadriceps muscles of both limbs. The total quadriceps, vastus lateralis, and vastus intermedius volume and cross-sectional area were significantly smaller in the anterior cruciate ligament-deficient limb. There was no significant atrophy of any other muscle or muscle group. Atrophy and activation failure explained more than 60% of the variance in quadriceps weakness (P = .004).
The quadriceps femoris weakens soon after acute anterior cruciate ligament injury. Activation deficits and atrophy occur and affect quadriceps strength. Rehabilitation techniques that address activation deficits as well as atrophy may be necessary to restore quadriceps strength.
前交叉韧带损伤后股四头肌无力很常见，尤其是在那些对损伤代偿不佳的患者（“非代偿者”）中。在这一人群中已证实存在萎缩和激活失败，但尚未与股四头肌无力直接相关。
（1）非代偿者的股四头肌力量、体积和横截面积将小于对侧肌肉，而其他肌肉不会出现萎缩。（2）将观察到股四头肌激活缺陷。（3）萎缩和激活失败将导致这些患者的股四头肌无力。
横断面研究，证据等级为3级。
17例单纯前交叉韧带损伤的非代偿者在损伤后平均2个月接受股四头肌爆发叠加力量和激活测试以及12块肌肉的磁共振成像检查。通过从轴向图像中数字重建每块肌肉并计算肌肉体积和峰值横截面积来描述形态学特征。
前交叉韧带损伤侧的股四头肌明显比未受伤侧弱（平均25%）；双侧股四头肌均观察到激活失败（8%-10%）。前交叉韧带损伤侧的股四头肌总体积、股外侧肌和股中间肌的体积及横截面积明显较小。其他任何肌肉或肌肉群均无明显萎缩。萎缩和激活失败解释了股四头肌无力变异的60%以上（P = 0.004）。
急性前交叉韧带损伤后股四头肌很快变弱。激活缺陷和萎缩出现并影响股四头肌力量。可能需要采用针对激活缺陷以及萎缩的康复技术来恢复股四头肌力量。
