Tenotomy of the semitendinosus muscle under standing sedation versus general anesthesia: Outcomes in 20 horses with fibrotic myopathy.

To compare outcomes after semitendinosus tenotomy performed under standing sedation versus general anesthesia.Retrospective case series.20 horses with fibrotic myopathy of the semitendinosus muscle.Medical records (2002-2015) of horses undergoing tenotomy of the semitendinosus muscle for the treatment of fibrotic myopathy were reviewed. Signalment, history, affected muscles, restrain method, surgical procedures, and short-term outcome as well as complications were retrieved from records. Long-term outcome (gait and athletic function) was assessed at least 6 months postoperatively by conversation with the owners. Pearson's χ2 statistical analysis was used to compare restrain method and affected muscles with overall outcome. Significance was set at P < .05.Tenotomy of the semitendinosus muscle was performed under standing sedation in 8 horses and under general anesthesia in 12 horses. Follow-up period ranged from 9 months to 10 years. Gait was improved to variable degrees in 8 of 14 horses when the semitendinosus muscle alone was affected and in 4 of 6 horses when both the semitendinosus and semimembranosus muscles were involved (P = .11). Six of 8 horses treated under standing sedation and 6 of 12 horses treated under general anesthesia exhibited some improvement in the characteristic fibrotic gait (P = .4473). Five of 6 athletic horses treated under standing sedation and 6 of 9 athletic horses treated under general anesthesia returned to their preinjury level of athleticism. Horses treated under standing sedation had no incisional complications; 2 of 12 horses treated under general anesthesia exhibited incisional drainage.Tenotomy of the semitendinosus muscle in horses with fibrotic myopathy leads to similar improvement in gait, whether performed under standing sedation or general anesthesia.