Abstract
The recovery of lacerated skeletal muscles are said to be slow and incomplete. Often the intramuscular (IMβ) nerve is concomitantly cut, but never repaired. We questioned whether the IMβnerve should also be reanastamosed before repairing the skeletal muscle. Before answering this, it was necessary to know if the cut IM nerve would have an effect on the recovery of the segment of muscle distal to the level of the laceration. This study investigates the recovery of lacerated muscles after repair, and compares a complete muscle laceration where the main IMβnerve was concomitantly cut and an incomplete muscle laceration where the IMβnerve was preserved intact. The medial gastrocnemius (MG) of the adult male New Zealand White rabbit was used, with the contralateral muscle as a sham control. The laceration was at the proximal quarter of the muscle, distal to the entry point of the nerve branch from the tibial nerve into the muscle belly. Twentyβeight weeks postβrepair, the lacerated MG with the IMβnerve intact showed improved muscle wet weight, near normal morphology and contractile properties, and return of muscle fiber type mix and size. The repaired lacerated MG with their IMβnerve concomitantly cut demonstrated loss of muscle wet weight, obvious fibrosis, mononuclear proliferation with fatty infiltration, increase in typeβ1 fibers and muscle fiber atrophy in the distal portion. We postulate that it might be important to repair the intramuscular nerve branch by microanastomosis when repairing a vital skeletal muscle that is lacerated. Β© 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res