Background:

Anterior cruciate ligament (ACL) trauma and ACL reconstruction (ACLR) are associated with the loss of strength and function of the muscles that span the knee joint. The underlying mechanism associated with this is not completely understood.

Purpose:

To determine whether the duration of tourniquet use during ACLR has an effect on knee extensor muscle contractile function and size at the cellular (ie, fiber) level 3 weeks after surgery and at the whole-muscle level at 6 months after surgery.

Study Design:

Descriptive laboratory study and case series; Level of evidence, 4.

Methods:

Study participants sustained an acute, first-time ACL injury. All participants underwent ACLR with the use of a tourniquet placed in a standardized location on the thigh; the tourniquet was inflated (pressure range, 250-275 mm Hg), and the time of tourniquet use during surgery was documented. Participants were evaluated 1 week before surgery (to measure patient function, strength, and subjective outcome with the Knee injury and Osteoarthritis Outcome Score [KOOS] and International Knee Documentation Committee [IKDC] score), at 3 weeks after ACLR surgery (to obtain muscle biopsy specimens of the vastus lateralis and assess muscle fiber cross-sectional area, contractile function, and mitochondrial content and morphometry), and at 6 months after ACLR (to evaluate patient function, strength, and subjective outcomes via KOOS and IKDC scores). Data were acquired on both the injured/surgical limb and the contralateral, normal side to facilitate the use of a within-subjects study design. Results are based on additional analysis of data acquired from previous research that had common entry criteria, treatments, and follow-up protocols.

Results:

At 3 weeks after ACLR, the duration of tourniquet use at the time of surgery did not explain the variation in single–muscle fiber contractile function or cross-sectional area (myosin heavy chain [MHC] I and II fibers) or subsarcolemmal and intermyofibrillar mitochondrial content or morphometry. At 6 months after ACLR, the duration of tourniquet use was not associated with the peak isometric and isokinetic torque measurements, patient function, or patient-reported outcomes.

Conclusion:

The duration of tourniquet use at the time of ACLR surgery did not explain variation in muscle fiber size, contractile function, or mitochondrial content at 3 weeks after surgery or strength of the quadriceps musculature or patient-reported function or quality of life at 6-month follow-up.

中文翻译：

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与前交叉韧带重建相关的大腿止血带使用持续时间不会在手术后 3 周内产生股四头肌的细胞水平收缩功能障碍

背景：

前交叉韧带 (ACL) 创伤和 ACL 重建 (ACLR) 与跨越膝关节的肌肉的力量和功能丧失有关。与此相关的潜在机制尚不完全清楚。

目的：

确定在 ACLR 期间使用止血带的持续时间是否对膝关节伸肌收缩功能和大小有影响，在手术后 3 周在细胞（即纤维）水平和在手术后 6 个月在整个肌肉水平。

学习规划：

描述性实验室研究和案例系列；证据等级，4。

方法：

研究参与者遭受了急性、首次 ACL 损伤。所有参与者都使用放置在大腿标准化位置的止血带进行了 ACLR；止血带充气（压力范围，250-275 毫米汞柱），并记录手术期间使用止血带的时间。参与者在手术前 1 周接受评估（用膝关节损伤和骨关节炎结果评分 [KOOS] 和国际膝关节文献委员会 [IKDC] 评分测量患者功能、力量和主观结果），在 ACLR 手术后 3 周（获得肌肉股外侧肌活检标本并评估肌纤维横截面积、收缩功能、线粒体含量和形态测定），以及 ACLR 后 6 个月（通过 KOOS 和 IKDC 评分评估患者功能、力量和主观结果）。采集了受伤/手术肢体和对侧正常侧的数据，以促进使用受试者内研究设计。结果基于对从具有共同进入标准、治疗和后续方案的先前研究中获得的数据的额外分析。

结果：

在 ACLR 后 3 周，手术时使用止血带的持续时间并不能解释单肌纤维收缩功能或横截面积（肌球蛋白重链 [MHC] I 和 II 纤维）或肌膜下和肌原纤维间线粒体的变化内容或形态学。在 ACLR 后 6 个月，止血带使用的持续时间与峰值等长和等速扭矩测量、患者功能或患者报告的结果无关。

结论：

ACLR 手术时使用止血带的持续时间并不能解释术后 3 周时肌纤维大小、收缩功能或线粒体含量的变化，也不能解释股四头肌肌肉组织强度或患者报告的功能或 6 个月时生活质量的变化跟进。