Paper 23: Lateral extra-articular tenodesis does not alter gait biomechanics after acl reconstruction in a pediatric population: a motion analysis study

Objectives: Lateral extra-articular tenodesis (LET) is increasingly performed in combination with anterior cruciate ligament reconstruction (ACLR) to reduce graft failure risk and improve rotatory knee stability in high-risk patients. However, concerns remain that LET may overconstrain the lateral compartment and alter normal gait biomechanics, particularly in pediatric populations where high activity levels and ligamentous laxity increase reinjury risk. The objectives of this study was to compare postoperative gait biomechanics in pediatric patients who underwent ACLR with LET (ACLR+LET) to those who underwent isolated ACLR (iACLR), and to healthy controls, using a clinically accessible motion analysis tool, knee kinesiography. We hypothesized that patients undergoing ACLR with LET would show altered gait biomechanics postoperatively compared to those undergoing isolated ACLR.
Methods: This observational study included pediatric patients (<=18 years old) who underwent ACLR with or without LET between January 2023 and August 2025, and a prospective cohort of healthy controls. All participants underwent standardized gait assessment with knee kinesiography (KneeKGTM) pre- and postoperatively or bilaterally (controls). Primary outcomes were three-dimensional knee kinematic waveforms in the sagittal, frontal, and transverse planes during walking. Demographic characteristics were also collected. Gait curves were analyzed using Statistical Parametric Mapping 1D (SPM1D). Three primary comparisons were performed: (1) ACLR+LET knees vs iACLR knees, (2) ACLR+LET knees vs healthy control knees, and (3) iACLR knees vs healthy control knees.
Results: Sixty-four pediatric patients (64 knees) who underwent ACL reconstruction were included: 35 patients (35 knees) in the iACLR group and 29 patients (29 knees) in the ACLR+LET group. Both surgical cohorts were compared to a prospective control group of 15 healthy participants (30 knees). At 4 months postoperatively, no significant differences in knee kinematics were found between the ACLR+LET and iACLR groups. Compared to healthy controls, both surgical groups demonstrated similar gait adaptations with greater flexion during stance phase (ACLR+LET: 14.51° +- 4.45°, iACLR: 14.45° +- 5.17° vs. controls: 9.57° +- 4.24°; p < 0.001 for both comparisons).
Conclusions: In pediatric patients, combining LET with ACLR did not alter gait biomechanics compared to isolated ACLR. These results support the safe use of LET in young patients when addressing residual rotatory instability, without compromising physiological knee motion. This study provides novel motion analysis data in pediatric ACL reconstruction, supporting the safety of LET as an adjunct to ACLR. These findings may reassure clinicians regarding potential biomechanical consequences and guide surgical decision-making in high-risk pediatric populations.