Abstract
Background:
Anterior cruciate ligament reconstruction (ACLR) in pediatric patients is performed to restore knee stability and enable return to sport. However, up to 50% of patients may develop post-traumatic osteoarthritis (PTOA) within 12–14 years despite surgical success. Abnormal gait mechanics are suspected contributors, yet objective gait assessment is rarely integrated into pediatric rehabilitation protocols.
Hypothesis:
We hypothesized that pediatric patients would exhibit persistent abnormal gait kinematics in the early postoperative period following ACLR, particularly in the sagittal and axial planes, and that these abnormalities would differ significantly from those of both the contralateral limb and healthy controls.
Methods:
Patients aged 12–18 years with isolated ACL tears were included. Those with prior lower limb injuries, scoliosis >15°, or neuromuscular conditions were excluded. Patients underwent 3D gait analysis using KneeKG both before and 3–4 months after surgery. Kinematic parameters—sagittal (flexion/extension), axial (rotation), coronal (ab-/adduction), and anterior-posterior translation—were compared between ACL-deficient (ACLD), post-ACLR, contralateral, and healthy control limbs using SPM1d analysis.
Results:
Data were collected from 24 contralateral limbs and 15 age-matched controls. In the sagittal plane, both ACLD and ACLR limbs exhibited significantly increased knee flexion during 1–55% of the stance phase when compared to healthy controls (p=0.0001), and from 33–54% of stance when compared to the contralateral limb (p=0.0016). These findings are consistent with a persistent hamstring facilitation strategy. In the axial plane, ACLD limbs demonstrated increased external tibial rotation (13–18%) compared to controls, reflecting a pivot-shift avoidance pattern. Notably, this rotational deviation resolved following ACLR. No significant differences were observed in the transverse plane or anteroposterior translation. There was no statistically significant improvement in sagittal plane kinematics between the pre- and early post-operative states.
Conclusion:
Despite successful reconstruction, pediatric patients continue to demonstrate sagittal plane gait abnormalities several months after ACLR, indicating incomplete neuromuscular recovery. While axial deviations such as pivot-shift avoidance appear to resolve early, flexion abnormalities persist and may contribute to altered joint loading and long-term PTOA risk. KneeKG provides a practical and objective tool to monitor recovery and may enhance rehabilitation strategies and return-to-sport decision-making in this high-risk population.
