Improving the ACL-RSI: effect of motion and force analysis during Return-to-sports test 3 months after ACL reconstruction
Authors: Terai Shozaburo , Zantop Christian , Zantop Thore 
Published: September 2020

Introduction: Psychological factors influencing the “return to play” fate of patients following ACL reconstruction are assessed using the ACL-Return to Sports after Injury Scale (ACL-RSI). A mean of 70 points distinguishes if the patients is likely to go back to training (Webster Feller 2018). Strategies of increasing this score hves not been reported yet. Aim of this study was to compare the ACL-RSI of patients three months after ACL reconstruction before and after a multifactorial “return-to-sports” test at our institution. Our hypothesis was that the “return-to-sports” test will increase the ACL-RSI value at three months after surgery. Hypotheses: We hypothesized that following a multi-factorial testing analysis, the LSI will increase compared to the value of the RSI score before testing. Methods: A total of 102 Patients undergoing ACL reconstruction are prospectively evaluated using the ACL-RSI at baseline data prior to surgery. ACL reconstructions were performed by a single surgeon with semitendinosus graft and standardized rehabilitation protocol. Follow-up was performed at 12 weeks postoperatively using a functional analysis including isokinetic strength measurements (BTE-primus), proprioceptive tests (MTF tests) and a 3d-motion analysis (myomotion, Noraxon) during bilateral drop jumps and single leg hop tests. To evaluate the effect of this testing battery on the ACL-RSI, the scale was assessed prior to “return-to-sports” test and after the test (n=80 at abstract submission). Results: Patients showed significantly improved ACL-RSI scale values at 3 months when compared to the baseline data prior to surgery. Using a cut-off of 70 points, 25% of the patients were determined under this cut-off. ACL reconstructed patients having a high value showed a lower increase in ACL-RSI at 3 months postoperatively when the value prior to the multifactorial “return-to-sport” test is compared to after test. Patients below 70 points before the functional testing (pre: 45,23 +/-11,5) showed after the test a value of 79,15 (+/-8,3) and an increase of 33,9 points. Compared to patients higher than 70 points prior to functional testing (pre: 71,4 +/-6,4; post 78,5 +/-8,3; increase 4,4) this increase is significantly lower. The was a high correlation of patients revealing better functional results in the functional analysis (isokinetic strength, proprioceptive test and a 3d-motion analysis) and a high score in the ACL-RSI scale. Conclusion: This prospective analysis of patients following semitendinosus ACL reconstruction with one single surgeon implicates that the use of a multifactorial “return-to-sports” analysis at 3 months postoperatively is able to improve the ACL-RSI score. Interestingly, the increase in the score was significantly higher in patients having a lower baseline and prior to test score when compared to patients showing a score that is more than 70 points. The effects of this elevated score over time remains unclear and needs to investigate in subsequent studies.