Gracilis muscle injury as a cause of lameness in two horses.

Injury to the gracilis muscle can cause acute, severe lameness in horses. Two female Quarter Horses that were used for barrel racing sustained gracilis muscle tear injuries. The site of injury was localized by direct infiltration of the area with mepivacaine. The extent of muscle tearing and seroma formation was determined via ultrasonographic evaluation. One horse developed fibrotic myopathy approximately 3 months after the original injury and underwent surgery to transect a palpable fibrous band at the previous injury site. Both horses returned to barrel racing 5 to 6 months after the injury These results suggest that horses sustaining a gracilis muscle injury have a good prognosis for returning to athletic use after an adequate period of muscle healing; however, fibrotic myopathy or muscle atrophy could be a complication of the injury resulting in persistent gait deficits.