Obesity and recovery of muscle strength after anterior cruciate ligament reconstruction in pediatric patients

Purpose: To explore factors influencing muscle strength after anterior cruciate ligament (ACL) reconstruction (ACLR) in pediatric patients. We hypothesized that obesity/overweight, autograft hamstring tendon, and concomitant injuries would be associated with slower muscle recovery. Methods: We retrospectively reviewed the records of pediatric ACLR patients during a 3-year period. Muscle recovery was defined as ≥85% of peak torque compared with the contralateral side. We categorized patients as either obese/overweight or normal weight. Statistical analysis was performed using Mann–Whitney U, analysis of variance, and χ² tests (α level < 0.05). Results: The study group consisted of 330 patients, of whom 198 (60%) and 231 (70%) met quadriceps and hamstring recovery criteria, respectively, at final testing (mean: 7.0 ± 3.2 months). Patients recovered hamstring and quadriceps strength at a mean of 5.3 ± 2.2 months and 6.1 ± 2.3 months, respectively. Hamstring muscle recovery took significantly longer in obese/overweight patients (mean: 5.7 ± 2.2 months) versus normal-weight patients (mean: 5.1 ± 2.1 months; p = 0.025), but quadriceps recovery did not (obese/overweight mean: 6.5 ± 2.6 months; normal-weight mean: 5.9 ± 2.1 months; p = 0.173). Conclusion: Concomitant injuries and graft type were not associated with length of time to recovery of muscle strength. Obesity/overweight was associated with delay in recovery of hamstring but not quadriceps strength.