Medical management of superficial digital flexor tendonitis: a comparative study in 219 horses (1992‐2000)

Abstract

Summary: Reasons for performing study : There is a lack of long‐term follow‐up data for outcome of medical treatment of superficial digital flexor (SDF) tendonitis. Objectives : To determine whether intralesional injection of hyaluronan, beta aminoproprionitrile fumarate (BAPN) or polysulphated glycosaminoglycans (PSGAG) or systemic administration of PSGAG yielded better results than a controlled exercise programme alone in the management of SDF tendonitis, with a minimum follow‐up period of 2 years after resumption of full work; and to determine whether reinjury rate was related to sports discipline and whether fibre alignment score (FAS) at 4 months could predict outcome. Methods : In Study 1, 50 horses were managed by controlled exercise alone ( Group A ), 50 were treated with intralesional injection of hyaluronan ( Group B ), 20 received intralesional and systemic treatment with PSGAG ( Group Ci ) and 30 received systemic treatment with PSGAG ( Group Cii ). Horses in Groups B, Ci and Cii followed the same controlled exercise programme as Group A. In Study 2 , 69 horses ( Group D ) were treated by intralesional injection of BAPN and followed a modified controlled exercise programme. Horses were re‐examined clinically and ultrasonographically at intervals. Follow‐up data were obtained for horses 2 years after resuming full work and for up to 6 years. Results : There was no significant difference in reinjury rate of the treated limb(s) between Groups A, B, Ci and Cii (42.5‐44.4%) (P>0.9). The reinjury rate (16%) in the treated limb(s) in Group D was significantly lower than in the other groups (P<0.001). However, when injury rate of the uninjured limb was considered, the results were similar to Study 1. In Study 2 , the FAS at 4 months after treatment was a good predictor of outcome (P<0.001). Reinjury rates for different disciplines were similar in the 2 studies, with the risk of reinjury ascending from showjumpers to event horses to National Hunt and flat racehorses. Conclusions : Treatment with BAPN reduced the risk of reinjury in the treated limb, although the overall rate of subsequent injury was not affected. FAS at 4 months after treatment is a good predictor of outcome in the treated limb(s). Potential relevance : This study provides long‐term follow‐up data in horses from a variety of sports disciplines that can be used to provide prognostic information.