CASE REPORT: Muscle Adaptation by Serial Sarcomere Addition 1 Year after Femoral Lengthening.Boakes, Jennette L MD*; Foran, Jared MD†; Ward, Samuel R PT, PhD‡; Lieber, Richard L PhD†Author Information From the *Department of Orthopaedic Surgery, Shriners Hospital for Children, Sacramento, CA; and the †Departments of Orthopaedic Surgery and Bioengineering and the ‡Department of Radiology, University of California and Veterans Administration Medical Centers, San Diego, CA. Received: June 2, 2006 Revised: August 14, 2006 Accepted: October 2, 2006 One or more of the authors (JLB, RLL) has received funding from the Orthopaedic Research and Education Foundation. The institution of the authors has received funding from the National Institutes of Health. Each author certifies that his or her institution has approved the reporting of this case report, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. Correspondence to: Richard L. Lieber, PhD, Department of Orthopaedics (9151), Veterans Administration Medical Center and University of California San Diego, 3350 La Jolla Village Drive, San Diego, CA 92161. Phone: 858-552-8585, ext. 7016; Fax: 858-552-4381; E-mail: [email protected] Clinical Orthopaedics and Related Research (1976-2007): March 2007 - Volume 456 - Issue - pp 250-253 doi: 10.1097/01.blo.0000246563.58091.af Buy Metrics Abstract A common complication of reconstructive surgery is muscle contracture and consequent loss of joint motion. This particularly occurs in surgical lengthening procedures where the muscle adaptive capacity seems to limit the extent of possible lengthening. We used intraoperative laser diffraction to determine the skeletal muscle adaptation that occurred in a 16-year-old girl who had 4-cm femoral lengthening for a leg-length discrepancy secondary to posttraumatic growth arrest. Fascicle length changed dramatically during distraction from a starting value of approximately 9 cm to a new length of 19 cm. In vivo vastus lateralis sarcomere length measured intraoperatively at the initial surgery was 3.64 μm, whereas sarcomere length measured 8 months later was 3.11 μm. The fact that fascicle length increased dramatically and in vivo sarcomere length decreased slightly reveals an increase in serial sarcomeres from 25,000 to 58,650. This direct measurement of fascicle length and sarcomere length confirms sarcomerogenesis in human skeletal muscle secondary to chronic length change, and shows the capacity of human muscle to adapt to length changes. © 2007 Lippincott Williams & Wilkins, Inc.