title: Differences in tibial rotation during walking in ACL reconstructed and healthy contralateral knees.
abstract: This study tested the hypotheses that in patients with a successful anterior cruciate ligament (ACL) reconstruction, the internal-external rotation, varus-valgus, and knee flexion position of reconstructed knees would be different from uninjured contralateral knees during walking. Twenty-six subjects with unilateral ACL reconstructions (avg 31 years, 1.7 m, 68 kg, 15 female, 24 months past reconstruction) and no other history of serious lower limb injury walked at a self-selected speed in the gait laboratory, with the uninjured contralateral knee as a matched control. Kinematic measurements of tibiofemoral motion were made using a previously-described point-cluster technique. Repeated-measures ANOVA (alpha=0.017) was used to compare ACL-reconstructed knees to their contralateral knees at four distinct points during the stance phase of walking. An offset towards external tibial rotation in ACL-reconstructed knees was maintained over all time points (95%CI 2.3+/-1.3 degrees ). Twenty-two out of twenty-six individuals experienced an average external tibial rotation offset throughout stance phase. Varus-valgus rotation and knee flexion were not significantly different between reconstructed and contralateral knees. These findings show that differences in tibial rotation during walking exist in ACL reconstructed knees compared to healthy contralateral knees, providing a potential explanation why these patients are at higher risk of knee osteoarthritis in the long-term.
authors.affiliation: Biomechanical Engineering, Department of Mechanical Engineering, Stanford University, Stanford, CA, USA. sscanlan@stanford.edu
authors.forename: Sean F
authors.initials: SF
authors.lastname: Scanlan
authors.forename: Ajit M W
authors.initials: AM
authors.lastname: Chaudhari
authors.forename: Chris O
authors.initials: CO
authors.lastname: Dyrby
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Andriacchi
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology* / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D005260:Female; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D009068:Movement / Q000502:physiology*; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures; D012399:Rotation; D013977:Tibia / Q000503:physiopathology*; D016896:Treatment Outcome; D016138:Walking