Superior 2-Year Functional Outcomes Among Young Female Athletes After ACL Reconstruction in Just 10 Post-Operative Return-to-Sport Training Sessions
Authors: Capin Jacob John , Failla Mathew , Smith Angela H. , Zarzycki Ryan , Dix Celeste , Johnson Jessica Lindsey , Risberg May Arna , Huston Laura J. , Spindler Kurt P. , Snyder-Mackler Lynn 
Published: July 2019

Objectives: Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly acceptable and are worse among young female athletes. Developing better rehabilitation and return-to-sport (RTS) training programs and evaluating their outcomes are essential. The purposes of this study were to: 1) Test the effect of strength, agility, plyometric, and secondary prevention (SAPP) exercises with and without perturbation training (SAPP+PERT) on strength, hops, functional outcomes, activity levels, and RTS rates in young female athletes 1 and 2 years after ACLR; and 2) Compare 2-year functional outcomes and activity levels among young female athletes in the ACL-SPORTS trial to homogeneous cohorts who completed criterion-based post-operative rehabilitation alone (MOON) and in combination with extended pre-operative rehabilitation (DE-Oslo). We hypothesized that SAPP+PERT would result in superior outcomes compared to SAPP alone; and female athletes who structured completed post-operative RTS training, compared to those who did not, would have higher functional outcomes. Methods: Aim 1 is a randomized control trial (NCT01773317) while aim 2 is a cohort study. For aim 1, we enrolled 39 female athletes, based on power calculations described previously. Athletes were enrolled 3-9 months after primary ACLR when they achieved impairment resolution. Participants were randomized to 10 SAPP or SAPP+PERT sessions (˜2x/week) and tested 1 and 2 years after ACLR on quadriceps strength, 4 hop tests, functional outcome measures, and RTS rates. We used 2x2 mixed-model ANOVA to test aim 1 (α = 0.05). Secondary to no group differences, we collapsed across SAPP and SAPP+PERT for aim 2. We applied inclusion/exclusion criteria and constrained sex (female) and age (13 to < 25 years) to compare these athletes who received post-operative RTS training (ACL-SPORTS) to homogeneous subsets who completed criterion-based post-operative rehabilitation alone (MOON) and combined with extended pre-operative rehabilitation (DE-Oslo) on 2-yr outcomes: the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Marx Activity Rating Scale. We tested aim 2 using 3-way ANOVA and Chi-Square test of proportions to compare the proportion of individuals in each group who met the Patient Acceptable Symptom State (PASS) thresholds. Results: There were no significant or clinically meaningful differences between SAPP and SAPP+PERT; groups were collapsed for comparison to the other cohorts. ACL-SPORTS had the highest scores on every outcome (Table 1). A higher proportion of ACL-SPORTS achieved the PASS thresholds for the IKDC, KOOS Activities of Daily Living, and KOOS Sport and Recreation (Fig 1, p ≤ .01). Conclusion: Our 1st hypothesis, that the addition of perturbation training would result in superior clinical and functional outcomes, was not supported. Our 2nd hypothesis, that a structured RTS training program would improve outcomes over existing cohorts, was supported. Post-operative RTS training incorporating strengthening, agilities, and plyometrics but not necessarily perturbation training, may improve functional outcomes and activity levels among young female athletes after ACLR. We provide a prototype for RTS training that would be feasible to implement into group or non-clinical environments. Future RCTs should assess the comparative effectiveness of RTS training in various settings. [Table: see text][Figure: see text][Figure: see text][Figure: see text]