Bilateral Gait 6 and 12 Months Post-Anterior Cruciate Ligament Reconstruction Compared with Controls

Purpose To compare gait biomechanics throughout stance phase 6 and 12 months after unilateral anterior cruciate ligament reconstruction (ACLR) between ACLR and contralateral limbs and compared with controls. Methods Vertical ground reaction force (vGRF), knee flexion angle (KFA), and internal knee extension moment (KEM) were collected bilaterally 6 and 12 months post-ACLR in 30 individuals (50% female, 22 +/- 3 yr, body mass index = 23.8 +/- 2.2 kg center dot m(-2)) and at a single time point in 30 matched uninjured controls (50% female, 22 +/- 4 yr, body mass index = 23.6 +/- 2.1 kg center dot m(-2)). Functional analyses of variance were used to evaluate the effects of limb (ACLR, contralateral, and control) and time (6 and 12 months) on biomechanical outcomes throughout stance. Results Compared with the uninjured controls, the ACLR group demonstrated bilaterally lesser vGRF (ACLR, 9% body weight [BW]; contralateral, 4%BW) during early stance and greater vGRF during midstance (ACLR, 5%BW; contralateral, 4%BW) 6 months post-ACLR. Compared to the uninjured controls, the ACLR group demonstrated bilaterally lesser vGRF (ACLR, 10%BW; contralateral, 8%BW) during early stance and greater vGRF during midstance (ACLR, 5%BW; contralateral, 5%BW) 12 months post-ACLR. Compared with controls, the ACLR limb demonstrated lesser KFA during early stance at 6 (2.3 degrees) and 12 months post-ACLR (2.0 degrees), and the contralateral limb demonstrated lesser KFA during early stance at 12 months post-ACLR (2.8 degrees). Compared with controls, the ACLR limb demonstrated lesser KEM during early stance at both 6 months (0.011BW x height) and 12 months (0.007BW x height) post-ACLR, and the contralateral limb demonstrated lesser KEM during early stance only at 12 months (0.006BW x height). Conclusions Walking biomechanics are altered bilaterally after ACLR. During the first 12 months post-ACLR, both the ACLR and contralateral limbs demonstrate biomechanical differences compared with control limbs. Differences between the contralateral and control limbs increase from 6 to 12 months post-ACLR.