Isokinetic Knee Strength and Patient-Reported Outcomes Differ Between Graft Types in Adolescents After Anterior Cruciate Ligament Reconstruction: A Multicenter Study.

BACKGROUND

Graft selection can influence strength and patient-reported outcomes (PROs) in adults undergoing anterior cruciate ligament reconstruction (ACLR). Yet, there is a lack of high-quality evidence comparing these results in adolescents.

PURPOSE/HYPOTHESIS: The purpose of this study was to determine differences in quadriceps and hamstring strength and PROs between adolescents with bone-patellar tendon-bone (BPTB), quadriceps tendon (QT), and hamstring tendon (HT) autografts. It was hypothesized that patients with QT and BPTB grafts would have greater impairments in knee extension, patients with HT grafts would have greater impairments in knee flexion, but PROs would be similar between graft types.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 522 adolescents (mean age, 16.8 ± 1.8 years; 55% female) completed isokinetic knee strength testing at 60 deg/s, the International Knee Documentation Committee (IKDC) subjective knee form, the pediatric IKDC (Pedi-IKDC) subjective knee form, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale at 7.8 ± 1.5 months after ACLR. Weight-normalized strength was compared via linear mixed-effects models, and PROs were compared between graft types with the Kruskal-Wallis test.

RESULTS

After controlling for age, sex, time since surgery, and assessment site, patients with BPTB grafts had 10.8% less quadriceps strength in the ACLR limb ( = .05) than patients with QT grafts and 20.4% less quadriceps strength ( < .001) than patients with HT grafts, while patients with HT grafts had 9.6% more quadriceps strength ( = .01) than patients with QT grafts. Patients with BPTB grafts had 3.1% more hamstring strength ( < .01) than patients with QT grafts and 7.0% more hamstring strength ( < .001) than patients with HT grafts. Patients with HT grafts had 10.8% less hamstring strength ( < .01) than patients with QT grafts. Patients with QT grafts had lower IKDC scores (-7.2%; < .001) than patients with HT grafts and higher KOOS Sports scores (+4.5%; < .001) than patients with BPTB grafts. Patients with HT grafts had higher IKDC scores (+5.4%; < .001) and higher KOOS Sports scores (+5.1%; < .01) than patients with BPTB grafts. There were no differences in ACL-RSI scores ( = .37).

CONCLUSION

At 6 to 12 months after ACLR, patients with QT or BPTB grafts had worse normalized quadriceps strength but greater hamstring strength than patients with HT grafts. PROs were mixed, with no differences seen in ACL-RSI scores, but patients with HT grafts displayed greater self-reported function and a greater ability to participate in sport.