The Functional Movement Screen Is Not Associated With Self-reported Disability, Gait, Or Drop Vertical Jump In Individuals With ACL Reconstruction

Abstract

PURPOSE: To determine the associations between Functional Movement Screen (FMS) scores and the International Knee Documentation Committee (IKDC) questionnaire score, Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales scores, gait biomechanics, and drop vertical jump (DVJ) biomechanics in individuals with ACL reconstruction (ACLR). METHODS: 30 individuals with ACLR (53% female; 71.0±46.4 months post-ACLR; 22.6±1.8 years old; 11 patellar tendon graft, 12 hamstring tendon graft, 7 allograft) completed the IKDC and KOOS. Bilateral gait biomechanics were obtained from 5 trials on a 10m runway over 2 force plates. DVJ biomechanics were obtained using a 30cm box placed half their height from the force plates. FMS tasks were scored from 0-3 and summed for analysis. Bilateral gait biomechanics included the knee flexion angle (KFA) at heel contact, peak KFA, and vertical ground reaction force (vGRF) in the first 50% of stance. Bilateral DVJ biomechanics included the peak knee abduction angle, KFA at heel contact, peak KFA, and peak vGRF. A limb symmetry index (LSI) was calculated for peak KFA and peak vGRF during gait and DVJ. Involved limb values and LSI from gait and DVJ were used for analysis. Separate stepwise linear regression examined the association between the FMS and the IKDC, KOOS subscales, and gait and DVJ biomechanics after accounting for sex and time since ACLR. RESULTS: No associations were found between FMS score (Mean: 15.0±1.8) and the IKDC (Mean: 84.3±10.6) and KOOS (Mean: 72.0 – 95.6±1.8 – 21.3) after accounting for sex and time since ACLR (ΔR2=0.01 – 0.05, Δp=0.23 – 0.95). No associations were found between FMS score and involved limb biomechanical variables or their LSI’s for gait (ΔR2=0.01 – 0.07, Δp=0.17 – 0.79) and DVJ (ΔR2=0.01 – 0.11, Δp=0.08 – 0.99) after accounting for sex and time since ACLR. CONCLUSION: The IKDC and KOOS indicated that participants reported some knee-related disability. Conversely, the average FMS score was above the clinical threshold for dysfunctional movement patterns. Therefore, the FMS may not identify knee-related disability in individuals with ACLR. Moreover, FMS score was not associated with gait or DVJ biomechanics, and thus the FMS may not identify hazardous knee movement patterns in individuals with ACLR.