Energy Absorption Contribution and Return to Sport Scale After Primary Anterior Cruciate Ligament Reconstruction in Young Adult Athletes

Abstract

Research Question: 1) Do young athletes who returned to preinjury sport following primary anterior cruciate ligament reconstruction differ in the biomechanical loading distribution of energy across their lower extremity joints at the time of release from physical therapy compared to athletes who did not return to sport? 2) Can the ACL-Return to Sport Index (ACL-RSI) be used to predict a young athlete’s ability to return to pre-injury sport following primary anterior cruciate ligament (ACL) reconstruction?

Background and Significance: ACL reconstruction is a common injury in young athletes competing in sports that involve cutting and pivoting. This injury can pose significant physical and psychological barriers to return to sport. The objective of this study is to determine the impact of biomechanics and psychological factors on the ability to return to pre-injury sport following primary anterior cruciate ligament (ACL) reconstruction in young athletes.

Materials and Methods: A cohort of 39 athletes aged 13 - 25 who underwent primary ACL reconstruction with the intention of returning to preinjury sport. Biomechanics were evaluated with a jump-landing task and isokinetic quadriceps strength testing at the time of release from physical therapy to determine energy absorption contribution of the lower extremity joints. Psychological factors were evaluated using the ACL-return to sport index (ACL-RSI) at the time of release from physical therapy. Participants were followed up with at least 12 months after release from physical therapy and asked whether they returned to preinjury sport.

Results: Of the 39 participants, 28 returned to preinjury sport (RTS) and 11 did not (NRTS). There was a significant difference in peak ground reaction force between the groups in both the involved and uninvolved limbs (p=0.04). The involved hip in the RTS group had a significantly greater energy absorption contribution (EAC) (p=0.03). The NRTS group had a significantly higher EAC in both the involved (p=0.04) and uninvolved (p=0.03) ankles. There was no significant difference in the RSI score between the groups (p = 0.41).

Conclusion: Participants who returned to preinjury sport demonstrated altered biomechanical energy absorption compared to those who did not return to sport. ACL-RSI at the time of release from physical therapy may not be fully predictive of an athlete’s ability to return to sport at 1-year post-assessment.