A Secondary Injury Prevention Program May Decrease Contralateral Anterior Cruciate Ligament Injuries in Female Athletes: 2-Year Injury Rates in the ACL-SPORTS Randomized Controlled Trial.

The injury analysis was a secondary outcome, and power was calculated for the trial's primary biomechanical and functional outcomes, not for between-group injury differences. Only 39 female athletes were analyzed, and the paper states that more than 3000 participants would have been needed to adequately power a between-group injury comparison. The article states 40 athletes enrolled in the participants section and 39 enrolled in the results section. All participants received the same prevention exercises and education, so the contribution of any single component cannot be separated. The authors could not separate the effect of the training program from the objective return-to-sport criteria because all athletes had to pass those criteria. Return-to-sport status and athletic exposure were self-reported, and practice or game exposures were not counted. Two years may not capture all contralateral injuries, because some may occur later. Surgical technique, graft choice, and prior rehabilitation were not controlled. The paper reports 23% overall second injury rate in the results but 26% in the clinical implications.

The study was funded by the National Institute of Child Health and Human Development (NICHD AR048212). No author conflicts of interest are stated.

Do not read the lower contralateral injury rate compared with other published cohorts as evidence that the program prevents injuries. The trial found no group difference between the perturbation plus prevention group and the prevention-only group (p=0.77 for rate, p=0.25 for side), and this injury outcome was a secondary analysis.