Comparison Of Lower Extremity Joint Coordination Between Limbs In Individuals With ACL Reconstruction During Landing

Abstract

Individuals with anterior cruciate ligament reconstruction (ACLR) display smaller dorsiflexion angles (DFA) and knee flexion angles (KFA) during the landing and propulsive phases of jumping in their injured compared with their uninjured limb. Kinematic differences may be due to different sagittal plane ankle and knee joint coordination strategies that influence force attenuation and propulsion. PURPOSE: To compare peak DFA and KFA during landing and coordination pattern frequencies during the landing and propulsion phases of a drop vertical jump between the injured and uninjured limb of individuals with ACLR. METHODS: 15 females and 14 males with unilateral ACLR performed a drop vertical jump from a 30 cm box. Peak DFA and KFA were compared using paired t-tests. A modified vector coding technique and binning analysis were used to compare coordination patterns between sagittal plane DFA and KFA using Wilcoxon signed rank tests. RESULTS: The peak DFA was lower in the injured (121.07 ± 5.27°) compared with the uninjured (123.44 ± 4.70°) limb (Mean Difference: -2.37 [95%CI: -3.81, -.94], p = .002). The peak KFA was not different between the injured (-102.69 ± 14.78°) and uninjured (-103.77 ± 13.59°) limbs (Mean Difference: 1.08 [95%CI: -.66, 2.81], p = .215). The injured limb had more anti-phase (Z = -2.30, p = .022) and less exclusive knee flexion (KF) (Z = -2.11, p = .035) motion during landing than the uninjured limb. In-phase (Z = -.42, p = .676) and exclusive dorsiflexion (DF) (Z = -1.42, p = .157) motion were not different between the injured and uninjured limbs during landing. Anti-phase (Z = -1.32, p = .188), in-phase (z = -.69, p = .49), exclusive knee extension (Z = -1.85, p = .064), and exclusive plantarflexion (Z = -1.95, p = .052) motion were not different between limbs during propulsion. CONCLUSIONS: The injured limb had a smaller peak DFA, more simultaneous DF and KF, and less exclusive KF compared with the uninjured limb during landing. Individuals with ACLR may restrict peak DF in their injured limb during landing to limit isolated knee flexion as a protective mechanism to prevent anterior knee motion. More simultaneous DF and KF may be utilized to reduce the amount of force attenuation required from isolated KF. However, utilizing such a strategy for force attenuation may be perilous since the injured limb lands with less peak DF.