The relationship between knee muscle strength and knee biomechanics during running at 6 and 12 months after anterior cruciate ligament reconstruction

• Main Authors: Makoto Asaeda, Masataka Deie, Yoshifumi Kono, Yukio Mikami, Hiroaki Kimura, Nobuo Adachi
• Format: Article
• Language: English
• Published: Elsevier 2019-04-01
• Series: Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology
• Online Access: http://www.sciencedirect.com/science/article/pii/S221468731830164X

Background: Knee joint kinematics and kinetics during running recover at 12 months, not 6 months, following anterior cruciate ligament (ACL) reconstruction surgery. Knee muscle strength is a criterion used to assess an individual’s readiness to return-to-sports (RTS); however, the relationship between knee muscle strength and knee biomechanics is unclear. This study investigated the relationship between knee muscle strength and dynamic knee biomechanics during running at 6 and 12 months after ACL reconstruction surgery. Methods: Knee joint kinematics and kinetics during running were analyzed in 21 patients (10 males, 11 females) who underwent ACL reconstruction for a unilateral ACL deficiency. Kinematics and Kinetics were measured by three-dimensional motion analysis system, and Knee flexion angle was calculated using Point cluster technique and internal extension moment was calculated by the inverse dynamics method. Patients were compared to a control group matched by age, height and weight. Isokinetic knee extension and flexion strength in ACL-reconstructed patients were measured at 6 and 12 months postsurgery, by separated gender. Results: Knee flexion angle was significantly lower in ACL patients at 6 months postsurgery compared to the control group (F (2, 62)=5.78, P=0.014). There were significant lower peak knee flexion angles in male groups than female (F (1, 62)=6.33, P<0.01). Knee extension moments were significantly lower in both male and female ACL patients compared to the control group at 6 and 12 months postsurgery (F (2, 62)=12.05, P<0.01(6 months), P=0.034(12 months)), and there were significant correlations with knee extension moments and maximum torque of knee extension/flexion (P<0.05). At 12 months after surgery, knee joint kinematics in ACL patients were restored. Both peak knee angle and knee extension moment were significantly associated with maximum knee extension/flexion torque values in female patients at 12 months postsurgery. Conclusions: Dynamic knee biomechanics during running were not restored 6 and 12 months after ACL reconstruction both male and female. It is necessary to strengthen knee extension and flexion muscles to restore knee kinetics during running, especially female patients.