Skeletal Muscle Cellular Contractile Dysfunction After Anterior Cruciate Ligament Reconstruction Contributes to Quadriceps Weakness at Six-Month Follow-Up

Muscle dysfunction following anterior cruciate ligament reconstruction (ACLR) may evolve from alterations in muscle contractility at the myofilament protein level. Using a prospective, within-subject case control design, we evaluated cellular-level contractility, cross-sectional area (CSA), and myosin heavy chain (MHC) isoform expression on single muscle fibers 3-weeks post ACLR, and evaluated their relationship to whole muscle strength and patient-oriented outcomes 6 months post-op. Biopsies of the vastus lateralis were performed 3-weeks post-ACLR in 11 subjects (5 female, mean age ±SD = 24.7 ± 6.5 yr, height = 172.7 ± 8.2 cm, mass = 75.7 ± 12.5 kg) following first-time ACL rupture and whole muscle strength and self-reported pain, function, and quality of life assessed 6-months post-ACLR. At 3-weeks post ACLR, force production was reduced (P