Prolonged alterations to muscle following knee surgery and physical therapy

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Quadriceps strength reductions after an anterior cruciate ligament reconstruction of greater than 20-40% occur at a critical time when physical therapy is ending and the individual begins to return to activities that require higher muscular demands. The reduction in quadriceps strength during this period of time has been associated with poorer outcomes. The measurement of muscular strength after rehabilitation to date has been limited to gross measurements, with little known of how the individual heads of the quadriceps such as the Vastus Lateralis respond to surgery. Therefore we propose two specific aims: (Aim 1) Assess the quadriceps muscle (vastus lateralis) fascicle length, pennation angle, and physiological cross sectional area before and after rehabilitation for ACL reconstruction. (Aim 2) Characterize muscle morphology through quantification of quadriceps muscle fiber type, fiber cross sectional area, and fibrosis after completing rehabilitation for an ACL reconstruction. In Aim 1, Dr. Noehren will use DTI-MRI established by one his mentors, Dr. Damon, to measure muscle properties strongly linked to maximum force production. In Aim 2, he will perform histo and immuno-histiochemical analysis in Dr. Peterson’s laboratory of muscle biopsies taken from the Vastus Lateralis of the same group from Aim 1 to categorize the adaptations to muscle fiber cross sectional area, fiber type, as well as fatty in-growth and fibrosis. Dr. Esser will assist with training for this aim and the interpretation of the results. The aims will couple data from non invasive imaging with detailed cellular analysis of muscle which will inform rehabilitative practice. In addition Dr. Crofford will provide the training of translating the results into clinical research, clinical trials, and data analysis.
Effective start/end date2/1/131/31/16


  • National Institute Arthritis Musculoskeletal & Skin: $377,160.00


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