Racing performance of Thoroughbreds with superficial digital flexor tendonitis treated with desmotomy of the accessory ligament of the superficial digital flexor tendon: 332 cases (1989-2003).

Abstract

To assess postoperative probability of racing, career longevity, and convalescent time in Thoroughbred racehorses with moderate to severe superficial digital flexor tendonitis (SDFT) in the forelimbs treated by desmotomy of the accessory ligament of the superficial digital flexor tendon (ie, superior check ligament desmotomy [SCLD]). Retrospective case series. 332 Thoroughbred racehorses with SDFT consecutively treated by means of SCLD. Medical records and racing records were reviewed to assess return to racing, number of races completed, time to first race, and lifetime performance. The horses were categorized as raced or unraced prior to and after surgery. Descriptive statistics including age and treated limb were also recorded. Of 332 horses, 228 (69%) returned to racing following injury and treatment. Seventy-eight of 118 (66%) horses that had not raced prior to injury and 150 of 214 (70%) horses that had raced prior to injury raced after treatment. Seventeen of 39 (44%) horses ≥ 5 years old raced following injury and treatment and 211 of 293 (72%) horses ≤ 4 years old returned to racing. There was no difference in the percentages of horses returning to racing for 2-, 3-, or 4-year olds. Postoperative infections occurred in 6 of the 332 (2%) horses. Median time to first race for horses that raced after surgery was 302 days (range, 48 to 1,120 days; mean ± SD, 341 ± 153 days), with a median of 8 starts/horse after surgery (range, 1 to 109 starts; mean ± SD, 14 ± 15.8 starts). Of 228 horses that returned to racing, 159 (70%) raced ≥ 5 times after surgery. Sex and treated limb did not have a significant effect on return to racing. However, horses ≥ 5 years old were significantly less likely to return to racing, compared with younger horses. In horses with unilateral SDFT and < 5 starts, the affected and contralateral limbs were both treated, but return to racing was not significantly different between horses treated bilaterally versus unilaterally. 228 of 332 (69%) horses with SDFT of the forelimb treated with SCLD successfully returned to racing. Convalescent times were shorter, compared with previous recommendations, and treated horses had a longer racing career after surgery than has been described for other treatment modalities. The results of the present study support consideration of SCLD as part of a treatment plan for SDFT in Thoroughbred racehorses.