Longitudinal changes in knee muscles isokinetic strength and dynamic performance in patients following reconstruction of the anterior cruciate ligament
Affiliations: [a] Department of Rehabilitation Medicine, Hallym University Dongtan Sacred Heart Hospital, Seoul, Korea | [b] Department of Rehabilitation Medicine, Dongmasan General Hopsital, Dongmasan, Korea | [c] Department of Physical Medicine and Rehabilitation, Soonchunhyang University Bucheon Hospital, Bucheon, Korea | [d] Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul, Korea | [e] Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
Correspondence:
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Corresponding author: Jae-Young Lim, Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173, Bundang-gu, Seongnam 13620, Korea. Tel.: +82 31 787 7732; Fax: +82 31 787 4056; E-mail: drlim1@snu.ac.kr.
Abstract: BACKGROUND: Relatively little is known about the longitudinal changes in strength and function in the early phase compared to long term outcome following reconstruction of the anterior cruciate ligament (ACL). OBJECTIVE: To assess the isokinetic concentric strength of the knee extensors and flexors as well as the distance jumped in the one-legged hop test in patients before and at 3, 6 and 12 months after (6 and 12 months for the hop test) reconstruction of the ACL. METHOD: Seventy-three men, aged 18–50 years took part in the study. The primary outcome measures were the International Knee Documentation Committee (IKDC) scores at 3, 6, and 12 months after surgery and one-legged hop test at 6 and 12 months after post-reconstruction. RESULTS: There was a consistent increase in muscular strength between 3 and 12 months post-reconstruction. Fair but significant correlations were found between the IKDC score at 12 months and the peak moment of the knee extensors at 3 and 6 months (r= 0.450 and 0.429, respectively, p= 0.012). 60.2% of the participants satisfied the criteria of successful outcome based on IKDC scores and one-legged hop test at 12 months. The peak moment of knee extensor measured at 3 months after surgery was a significant predictive factor for successful outcome (p= 0.021). Patients in whom muscle strength had recovered well by 3 months after ACL reconstruction were more active in terms of sporting activities and exhibited better dynamic performance at the 1-year follow-up. CONCLUSION: Knee extension strengthening in early phase is crucial to restoring sporting performance after ACL reconstruction.
Keywords: Isokinetic strength, ACL, IKDC score, one-legged hop test
