BACKGROUND Pass rates for return-to-play evaluations are alarmingly low for patients after anterior cruciate ligament reconstruction (ACLR). Since timing of return to play is a complicated decision, it is important that patients be given optimal time to realize meaningful improvements in strength that warrant additional testing. PURPOSE To (1) compare outcomes among patients assessed at different time points after ACLR, (2) determine strength gains indicative of improvements in subjective function, and (3) determine the amount of time necessary to achieve meaningful strength gains. STUDY DESIGN Cross-sectional/case-control study; Level of evidence, 3. METHODS A total of 293 patients participated in the study after ACLR (mean ± SD, 23.2 ± 10.1 years old; n = 142 female participants; 6.4 ± 0.9 months after ACLR). Participants were stratified on the month of their evaluation after ACLR: 5 to 6 months (n = 122), 6 to 7 months (n = 102), 7 to 8 months (n = 43), and 8 to 9 months (n = 26). The International Knee Documentation Committee (IKDC) subjective form and knee extensor and flexor torque and symmetry, as assessed through an isokinetic dynamometer, were compared among groups. Forty patients (20 female participants, 20.4 ± 7.1 years old) were referred for subsequent testing (2.14 ± 0.78 months after initial visit). Subjective improvement between visits was defined as a ≥9-point change of the IKDC score. Thresholds of knee extensor torque and symmetry indicative of subjective improvement and the time between assessments needed to achieve these strength improvements were determined. RESULTS Patients between 5 and 6 months (IKDC, 79.7; interquartile range [IQR], 70.1-88.5) had lower subjective function compared to patients between 6 and 7 months (IKDC, 83.9; IQR, 74.5-92.0; P = .019) and 8 and 9 months after ACLR (IKDC, 89.1; IQR 75.8-92.3; P = .026). Patients between 5 and 6 months (1.41 N·m/kg; IQR, 1.16-1.73 N·m/kg]) had lower knee extensor torque compared to patients 6 and 7 months (1.59 N·m/kg; IQR, 1.23-1.95 N·m/kg; P = .013) and 7 and 8 months after ACLR (1.62 N·m/kg; IQR, 1.30-1.86 N·m/kg; P = .046). Patients between 5 and 6 months (66.4%; IQR, 54.2-78.6) had lower symmetry compared to patients between 6 and 7 months (71.8%; IQR,61.1-82.9; P = .019) and 8 and 9 months afterACLR (75.2%; IQR, 66.6-87.7; P = .014). Of the 40 patients that completed follow-up assessments, an increase in knee extensor torque of 0.22 N·m/kg and symmetry of 5.75% discriminated patients that achieved subjective improvement. A period of 1.97 months between assessments discriminated those that achieved the established symmetry threshold. CONCLUSION Patients demonstrate increasing subjective and quadriceps function when tested at later time points from surgery; however, the observed values are low, suggesting that at 9 months patients are demonstrating deficits that may be improving. Approximately 2 months is needed to observe clinically meaningful improvements.

中文翻译：

---

从前交叉韧带重建中恢复的患者中，在进行系列的“重返比赛”评估之间需要多少时间才能获得具有临床意义的强度优势？

背景技术对于前十字韧带重建（ACLR）后的患者，重返比赛评估的合格率低得惊人。由于恢复比赛的时机是一个复杂的决定，因此给患者最佳的时间以实现有意义的力量提高，这需要进行额外的测试，这一点很重要。目的（1）比较ACLR术后不同时间点评估的患者的结局，（2）确定指示主观功能改善的力量增加，（3）确定实现有意义的力量增加所需的时间。研究设计横断面/病例对照研究；证据级别，第3级。方法共有293名患者在ACLR后参加了研究（平均±SD，23.2±10.1岁； n = 142名女性参与者； ACLR后6.4±0.9个月）。在ACLR后的评估当月对参与者进行分层：5至6个月（n = 122），6至7个月（n = 102），7至8个月（n = 43）和8至9个月（n = 26）。比较了通过等速测力计评估的国际膝关节文献委员会（IKDC）的主观形式，膝伸肌和屈肌力矩以及对称性。40名患者（20名女性参与者，20.4±7.1岁）被转诊接受后续检查（初次就诊后2.14±0.78个月）。两次就诊之间的主观改善定义为IKDC得分≥9分。确定表示主观改善的膝盖伸肌转矩和对称性的阈值，以及达到这些强度改善所需的两次评估之间的时间。结果5至6个月的患者（IKDC，79.7; 与6个月至7个月（IKDC，83.9; IQR，74.5-92.0; P = .019）和ACLR后8个月和9个月（IKDC，89.1; IQR，70.1-88.5）的患者相比，四分位数范围[IQR]，70.1-88.5）的主观功能较低IQR 75.8-92.3； P = .026）。5至6个月（1.41 N·m / kg； IQR，1.16-1.73 N·m / kg]）患者的膝部伸肌扭矩低于6和7个月（1.59 N·m / kg； IQR，1.23-I）。 1.95 N·m / kg； P = 0.013）以及ACLR后7个月和8个月（1.62 N·m / kg； IQR，1.30-1.86 N·m / kg； P = .046）。在5至6个月之间的患者（66.4％; IQR，54.2-78.6）的对称性低于6至7个月之间的患者（71.8％; IQR，61.1-82.9; P = .019）和ACLR后8至9个月的患者（75.2） ％； IQR，66.6-87.7； P = .014）。在完成随访评估的40例患者中，膝伸肌转矩增加0.22 N·m / kg，对称性增加5。75％的患者获得了主观改善。两次评估之间的1.97个月时间区分了达到既定对称性阈值的评估。结论当在手术后的较晚时间进行测试时，患者表现出主观和股四头肌功能增强；但是，观察到的值很低，表明在9个月时，患者表现出可能正在改善的缺陷。大约需要2个月才能观察到具有临床意义的改善。提示在9个月时，患者表现出可能正在改善的缺陷。大约需要2个月才能观察到具有临床意义的改善。提示在9个月时，患者表现出可能正在改善的缺陷。大约需要2个月才能观察到具有临床意义的改善。