Return-to-Sport Testing After Medial Patellofemoral Ligament Reconstruction in Adolescent Athletes.

Abstract

Background:Return to sport (RTS) after patellar stabilization surgery involves the return of strength and dynamic knee stability, which can be assessed using isometric strength and functional performance testing.Purpose:To investigate the results of isometric strength and functional RTS testing between the surgical and uninvolved limbs in adolescent patients who underwent medial patellofemoral ligament (MPFL) reconstruction for patellar instability.Study Design:Case series; Level of evidence, 4.Methods:A retrospective review of adolescent patients who underwent MPFL reconstruction identified 28 patients (20 female, 8 male) who also underwent isometric and functional RTS testing. Data were compared with the uninvolved limb. The recovery of muscle strength was defined by a limb symmetry index (LSI) ≥90%. Differences in peak torque were compared using the Wilcoxon signed-rank test. Correlations were examined between dependent and independent variables using the Spearman correlation.Results:The mean age of the patients was 14.9 years (range, 12-16 years). Reconstruction was performed with a hamstring autograft in 17 (60.7%) patients. Concomitant tibial tubercle osteotomy was performed in 10 (35.7%) patients. Testing was performed at a mean 7.4 months (range, 5.5-11.9 months) postoperatively. The mean LSIs for quadriceps and hamstring strength were 85.3% and 95.1%, respectively. For knee extension, there was a statistically significant difference between isometric peak torque measured in the surgical and uninvolved limbs (P = .001). Only 32.0% of patients passed all 4 hop tests. Also, 63.0% of patients achieved an anterior reach asymmetry of <4 cm on the Lower Quarter Y-Balance Test (YBT-LQ). There were no statistically significant differences in isometric strength testing, hop tests, or the YBT-LQ based on graft type or concomitant procedures. There was no correlation between isometric strength and performance on the YBT-LQ or hop tests.Conclusion:Adolescent athletes undergoing MPFL reconstruction may need prolonged rehabilitation programs beyond 8 months to allow the adequate recovery of muscle strength for safe RTS. There is a significant deficit in isometric quadriceps strength in the surgical limb after surgery. Further investigation is needed to determine safe RTS criteria after MPFL reconstruction in the pediatric and adolescent population.