Relationship Between Ankle Dorsiflexion Mobility and Functional Return to Sport Test Performance in Athletes Who Have Undergone ACL Reconstruction

BACKGROUND: Limited ankle dorsiflexion (DF) range has been associated with knee injuries and altered biomechanics during functional squatting and landing tasks. Prior studies correlating weight-bearing DF with altered landing mechanics have primarily used advanced motion capture technology, with limited research using clinically validated scoring tools. HYPOTHESIS/PURPOSE: To assess the relationship between decreased DF and functional testing performance in youth athletes who have undergone anterior cruciate ligament reconstruction (ACLR). METHODS: A retrospective review of standardized data was conducted on patients who had undergone ACLR at a pediatric sports medicine practice that had completed functional testing between December 2017 and November 2020. Patients with testing completed at a minimum of five months post-operatively, and who planned to return-to-sport (RTS) were included. Functional testing included validated protocols for the Y-Balance Test (YBT) and the Landing Error Scoring System (LESS), as well as a modified Single-Leg Squat Endurance Test (SLSET) utilizing the VAIL sports test scoring criteria. DF was measured in a weight-bearing lunge position off the front foot. Subjects were categorized into a pass or fail group based on their YBT and LESS scores (YBT≥94%, LESS≤4), and t-tests were performed to identify significant differences in DF between groups (α=0.05). Lastly, Pearson correlations were performed to identify potential relationships between DF and SLSET total score as well as normalized anterior reach collected as a component of the YBT (α=0.05). RESULTS: 303 patients (148 (48.8%) males, 15.94±2.15 years, 7.46±2.11 months post-operative) were included for analysis. Significant correlations were identified between DF and YBT composite score (p <0.001) and LESS total score (p <0.001; Table 1). Additionally, positive relationships were found between DF and both SLSET total score (p <0.001, r = 0.296) and anterior reach (p <0.001; r =0.400). Average values for DF, YBT, and LESS can be found in Table 2. CONCLUSION: In this pediatric ACLR population, decreased ankle dorsiflexion is associated with high risk movement patterns during functional testing. This study adds to the literature by identifying clinically applicable DF thresholds associated with passing scores on the YBT and LESS functional tests. Clinical interventions aimed at improving ankle dorsiflexion to >36° may be an important component of ACL rehabilitation.