Young Athletes Who Return to Sport Before 9 Months After Anterior Cruciate Ligament Reconstruction Have a Rate of New Injury 7 Times That of Those Who Delay Return

Abstract

Objective To investigate the association between sustaining a second anterior cruciate ligament (ACL) injury and (1) time to return to sport, (2) symmetrical muscle function, and (3) symmetrical quadriceps strength at the time of return to sport in young athletes after primary ACL reconstruction. Design Prospective cohort study. Methods Patient demographics and results from 5 tests of muscle function (2 strength tests and 3 hop tests) were extracted from a rehabilitation registry. A questionnaire was sent to athletes (15–30 years old) who were involved in knee-strenuous sport before the injury and had undergone primary ACL reconstruction to determine time of return to knee-strenuous sport (preinjury Tegner Activity Scale score of 6 or greater). We used the Cox proportional hazard regression model to analyze time to event. Results One hundred fifty-nine (32% of the initial sample) athletes (mean ± SD age, 21.5 ± 4.4 years; 50% female) were included. Athletes with a higher preinjury Tegner Activity Scale score had a higher rate of second ACL injury (hazard ratio = 2.1; 95% confidence interval: 1.2, 3.6; P<.01). Athletes who returned to knee-strenuous sport before 9 months after reconstruction had a higher rate of second ACL injury (hazard ratio = 6.7; 95% confidence interval: 2.6, 16.7; P<.001). There was no association between symmetrical muscle function or quadriceps strength and second ACL injury. Conclusion Returning to knee-strenuous sport before 9 months after ACL reconstruction was associated with an approximately 7-fold increased rate of sustaining a second ACL injury. Achieving symmetrical muscle function or quadriceps strength was not associated with new ACL injury in young athletes. J Orthop Sports Phys Ther 2020;50(2):83–90. doi:10.2519/jospt.2020.9071

Second ACL Injury Rates in Younger Athletes Who Were Advised to Delay Return to Sport Until 12 Months After ACL Reconstruction

“…This is positive given that previous studies have shown a marked increase in risk for further injury in athletes who return to sport before 9 months. 1,5 The delay in return to competitive sport did not reduce overall graft rupture or contralateral ACL injury rates at between 3 and 5 years postoperatively, and 33% of patients sustained at least 1 further ACL injury (graft rupture or contralateral ACL injury). Even when patients were categorized according to the actual time taken to return to competitive sport (before versus after 12 months), 32% who returned after 12 months sustained a subsequent ACL injury.…”

“…However, a recent study, which followed 159 patients aged 15 to 30 years who had mostly hamstring tendon grafts, found that returning to strenuous sports before 9 months after ACLR surgery was associated with a 7-fold increased rate for a second ACL injury compared with returning after 9 months. 1 While these studies show contradictory findings related to the timing of return to sport and subsequent ACL injury, the age range of patients varied, and as such, there may be merit in delaying a return to sport for younger patients. However, there is a paucity of data from which to draw robust conclusions.…”

Visual Perturbation to Enhance Return to Sport Rehabilitation after Anterior Cruciate Ligament Injury: A Clinical Commentary

“…Taken together, patients with ACL injuries may experience a loss of neural efficiency to engage in motor control, thereby contributing to both 1) impaired motor performance during dual-tasking or unanticipated movements and 2) an increased risk of secondary injury when attempting to rapidly increase motor complexity and environmental stimuli during early return to sport. 23,[63][64][65][66][80][81][82]…”

Poor Validity of Functional Performance Tests to Predict Knee Injury in Female Soccer Players With or Without Anterior Cruciate Ligament Reconstruction

“…These results are in line with most of the previous studies evaluating different test batteries, mainly including strength and hop performance tests. 5,27,44,45 However, 2 previous studies found an association between results in test batteries and sustaining a second ACL injury, but each test alone in the test batteries did not predict a second ACL injury. 25,43 Although there are no objective criteria 17 or test after an ACLR that can predict who will sustain a new injury, 18 it is considered the best approach to evaluate different components and use a battery of tests to inform the return to sport decision.…”