The importance of objective functional and balance testing in pediatric anterior cruciate ligament reconstruction for a safe return-to-sport: A two-year prospective study

Introduction/Objectives: Pediatric anterior cruciate ligament reconstruction (ACLR) outcomes, particularly long-term functional recovery and return-to-sport (RTS), remain debated and have not been well characterized in skeletally immature patients. This study evaluated functional movement competency, balance, and subjective knee function over a two-year follow-up in skeletally immature patients undergoing ACLR. Methods: Forty-four skeletally immature patients (15 girls, 29 boys, median age 14, range 9–16) undergoing transphyseal ACLR using semitendinosus tendon autograft in a single center were prospectively assessed. Functional Movement Screen (FMS), Simple Knee Value (SKV), Single Leg Squat (SLS), and Y-Balance Test-Lower Quarter (YBT-LQ) were administered preoperatively and at 6, 12, and 24 months postoperatively. Linear mixed models (ANOVA or non-parametric tests) and post-hoc comparisons were used for statistical analysis. Results: FMS scores improved throughout the two-year follow-up (p = 0.024), with increases observed from 6 months postoperatively. SKV also demonstrated continuous improvement at all time points (p < 0.001). However, no clinically meaningful correlation was found between SKV and FMS scores over time. SLS showed differences at 24 months for both the operated (0.6; p = 0.004) and contralateral leg (0.6; p = 0.03), though with minimal clinical relevance. YBT-LQ composite scores statistically improved bilaterally at 24 months, with minimal clinical relevance in the contralateral leg (−3.7; p = 0.011). The inter-limb difference in composite scores remained stable over time. YBT-LQ anterior reach distance progressively improved in the operated leg from 6 to 24 months. The inter-limb difference in anterior reach distance did not change over time. Conclusion: Pediatric ACLR patients demonstrated progressive functional improvement over two years, with additional improvements occurring beyond 12 months, supporting the potential value of extended rehabilitation and reassessment. The lack of correlation between subjective and objective measures underscores the need for comprehensive assessments, including functional tests, for safe RTS decisions, as subjective knee perception poorly reflects actual movement capacity. Level of evidence: II.