Neuromuscular recovery pattern after medial collateral ligament disruption in rats.
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.
Laurin
Jérôme
J
UMR CNRS 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, CC910-163, Ave. de Luminy, 13288 Marseille cedex 09, France.
Dousset
Erick
E
Mesure
Serge
S
Decherchi
Patrick
P
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005267:Femoral Nerve / Q000187:drug effects / Q000503:physiopathology; D006614:Hindlimb; D007718:Knee Injuries / Q000503:physiopathology*; D007719:Knee Joint / Q000473:pathology; D019344:Lactic Acid / Q000494:pharmacology; D017888:Medial Collateral Ligament, Knee / Q000293:injuries / Q000503:physiopathology*; D009043:Motor Activity / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D009468:Neuromuscular Diseases / Q000209:etiology / Q000503:physiopathology*; D011189:Potassium Chloride / Q000494:pharmacology; D052097:Quadriceps Muscle / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000502:physiology*; D012421:Rupture; D014945:Wound Healing / Q000502:physiology
D019344:Lactic Acid; D011189:Potassium Chloride