Knee loading asymmetries during gait and running in early rehabilitation following anterior cruciate ligament reconstruction: A longitudinal study

•Sagittal plane knee asymmetries during early gait persist with similar magnitude 4 months later.•Despite clinical normalization of gait, knee loading deficits present when running is initiated.•Large knee asymmetries during early gait are related to large asymmetries during running.•Emphasis should be placed on the early detection and restoration of loading symmetry during gait.

BackgroundNormalization of gait is expected 8-12 weeks after anterior cruciate ligament reconstruction and is a criterion for progression to running. Long-term persistence of sagittal knee loading deficits suggests that early goals are not met. Magnitude and progression of deficits in gait during this time and their relationship to deficits in running are not known.Methods12 individuals status-post reconstruction (5 males) underwent 3-dimensional motion analysis of gait after surgery: one (T1) and three (T2) months and at initiation of running (T3); and running T3. Repeated measures ANOVAs (limb × time) assessed differences in knee flexion, extensor moment impulse and negative work in gait; paired t-tests compared limbs during running; and Pearson's correlations determined associations between limb ratios (moment and work) in gait and running.FindingsLess flexion (− 4.4 (0.63) degrees; mean (SE)), 35% smaller extensor moment (− 0.15 (0.006) Nm ∗ s/kg) and 47% less work (− 0.03 (0.008) J/kg) were observed in the surgical knee during gait across time. Moment and work were 1.7 (− 0.1 (0.03) Nm ∗ s/kg) and 1.6 times greater (− 0.23 (0.047) J/kg) in non-surgical knee during running. Moment and work limb asymmetries correlated across time during gait (r = 0.778-0.929, P < 0.001) and to asymmetries during running.InterpretationLimb asymmetries in knee loading present one month after reconstruction persist 4 months post-reconstruction. Correlations between limb asymmetries during gait across time and to running suggest that early gait behaviors relate to longer-term loading. Greater attention should be placed on early gait training.