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This Article Full Text Full Text (PDF) All Versions of this Article: 107/1/98    most recent 00317.2009v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Laurin, J. Articles by Decherchi, P. PubMed PubMed Citation Articles by Laurin, J. Articles by Decherchi, P.

Neuromuscular recovery pattern after medial collateral ligament disruption in rats

UMR Centre National de la Recherche Scientifique 6233, Institut des Sciences du Mouvement, Etienne-Jules Marey, Université de la Méditerranée (Aix-Marseille II), Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, Faculté des Sciences du Sport de Marseille, Marseille, France

Submitted 23 March 2009 ; accepted in final form 19 May 2009

The medial collateral ligament (MCL) is one of the most injured ligaments during sport activities. The resulting joint damage effects on neuromuscular system remain unclear. Thus this study was designed to assess the changes in neuromuscular properties of vastus medialis muscle after MCL transection. Complete rupture of MCL was performed on rats, and dynamic functional assessment during locomotion was achieved before and once a week from 1–5 wk postlesion. Twitch properties and metabo- and mechanosensitive afferent fiber responses to specific stimuli were measured 1, 3, and 5 wk after MCL transection. Results indicated that maximum knee angle measured during the stance phase of the gait cycle was decreased during 3 wk after MCL injury and then recovered. Minimum knee angle measured during the stance phase was decreased during 2 wk and showed compensatory effects at week 5. A stepwise decrease in maximum relaxation rate-to-amplitude ratio concomitant with a stepwise increase in half-relaxation time were observed following MCL injury. Variations in metabosensitive afferent response to chemical (KCl and lactic acid) injections were decreased at week 1 and recovered progressively from week 3 to week 5 postlesion. Recovery of the mechanosensitive afferent response to vibrations was not totally complete after 5 wk. Our data indicate that alteration of the sensory pathways from the vastus medialis muscle could be considered as a source of neuromuscular deficits following MCL transection. Our results should be helpful in clinical purpose to improve the knowledge of the influence exerted by ligament rupture on the motor system and permit development of rehabilitation protocols and exercises more appropriate for recovery of functional stability.

mechanosensitivity; metabosensitivity; group III–IV afferent fibers; ligament transection; contractile properties