Little is known of the potential long-term gait alterations that occur after an anterior cruciate ligament (ACL) reconstruction. In particular, variables, such as impact loading, which have been previously associated with joint deterioration, have not been studied in walking and running after an ACL reconstruction. The purpose of this study was to define the alterations in impact forces, loading rates, and the accompanying sagittal plane kinematic and kinetic mechanics at the time of impact between the ACL-reconstructed group and a healthy control group.Methods
Forty females (20 with ACL reconstruction and 20 controls) participated in the study. An instrumented gait analysis was performed on all subjects. Between-group and between-limb comparisons were made for the initial vertical impact force, loading rate, and sagittal plane knee and hip angles as well as moments.Results
During walking and running, the ACL cohort had significantly greater initial vertical impact force (P = 0.002 and P = 0.001, respectively) and loading rates (P = 0.03 and P = 0.01, respectively), as well as a smaller knee extensor moment and hip angle during walking (P = 0.000 and P = 0.01, respectively). There was a trend toward a smaller knee moment and hip angle during running (P = 0.08 and P = 0.06, respectively) as well as a larger hip extensor moment during walking (P = 0.06) in the ACL group. No differences were found for hip extensor moment during running and for knee angles between groups during walking or running. Lastly, no between-limb differences were found for any variable.Conclusions
Gait deviations such as elevated impact loading and loading rates do not resolve long term after an individual has resumed previous activity levels and these may contribute to the greater risk of early joint degeneration in this population.