2025 ISAKOS Biennial Congress ePoster
Knee extensor strength after anterior cruciate ligament reconstruction in young patients: a comparison of quadriceps and hamstring tendons
Takuya Sengoku, PT, PhD, Kanazawa JAPAN
Yasushi Takata, MD, PhD, Kanazawa, Ishikawa JAPAN
Yoshihiro Ishida, MD, Kahoku-Gun, Ishikawa JAPAN
Naoki Takemoto, MD, Kanazawa, Ishikawa JAPAN
Manase Nishimura, MD, Kanazawa, Ishikawa JAPAN
Yushin Mizuno, MSc, PT, Kanazawa, Ishikawa JAPAN
Junsuke Nakase, MD, PhD, Kanazawa, Ishikawa JAPAN
Kanazawa University Hospital, Kanazawa, Ishikawa, JAPAN
FDA Status Not Applicable
Summary
ACL reconstruction using the quadriceps tendon in young athletes was associated with a marked reduction in knee extensor strength compared to hamstring tendon.
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Abstract
Introduction
The biggest issue after anterior cruciate ligament (ACL) reconstruction is the risk of reinjury. Traditionally, the hamstring tendon (HT) is most commonly used as the graft for ACL reconstruction. Recently, the quadriceps tendon (QT), which is believed to offer superior histological and mechanical strength, has gained attention as a preventive measure against reinjury. However, harvesting the QT, which is part of the knee extensor mechanism, may impact the recovery of knee extensor strength. This study aimed to clarify whether knee extensor muscle strength decreases after ACL reconstruction with QT.
Methods
The study included 126 young athletes aged 18 years or younger who underwent primary ACL reconstruction between 2014 and 2023. They were divided into two groups based on the graft used: 106 in the HT group and 20 in the QT group. Patients with a previous history of knee joint surgery and those who had pain during postoperative muscle strength testing were excluded. All patients underwent measurement of knee extensor strength (60°/s and 180°/s) using an isokinetic dynamometer at 3 and 6 months postoperatively. The limb symmetry index (LSI) of maximum torque, total workload, and time to peak torque was compared between the two groups. Additionally, the percentage of maximum torque the LSI achieved was calculated based on 70% at 3 months and 90% at 6 months postoperatively.
Results
The LSI of maximum torque at 3 months postoperatively was 76.6±18.0% in the HT group and, 59.9±16.4% in the QT group (p<0.01) at an angular velocity of 60°/sec, and 82.8±20.4% in the HT group and 67.4±16.4% in the QT group (p<0.01) at an angular velocity of 180°/sec, showing significant differences. Additionally, the LSI of maximum torque at 6 months postoperatively was 94.0±20.0% in the HT group and 76.1±16.9% in the QT group (p<0.01) at an angular velocity of 60°/sec, and 98.7±22.2% in the HT group and 79.1±12.8% in the QT group (p<0.01) at an angular velocity of 180°/sec, showing significant differences. Similarly, the QT group had a significantly lower total workload and significantly delayed time to peak torque.
Finally, the achievement rate of 70% LSI (60°, 180°) at 3 months postoperatively was clearly lower in the QT group (25.0%, 40.0%) than in the HT group (61.7%, 73.8%). Similarly, the rate of achieving 90% LSI (60°, 180°) at 6 months postoperatively was clearly lower in the QT group (25.0%, 20.0%) than in the HT group (56.1%, 61.7%).
Conclusion
ACL reconstruction using the QT in young athletes was associated with a marked reduction in knee extensor strength compared to HT. Enhancing knee extensor strength following ACL reconstruction with QT presents a major challenge for future research and clinical practice.