• horse;
  • tendinitis;
  • accessory ligament;
  • superficial digital flexor tendon;
  • Standardbred


Medical records and lifetime race results were obtained for 61 Standardbred racehorses treated consecutively from 1985 to 1992 with transection of the accessory ligament of the superficial digital flexor tendon (AL-SDF) for tendinitis of one or both forelimbs. A clinical diagnosis of tendinitis was confirmed in all cases by ultrasonographic examination. After surgery, 50 (82%) horses raced and 42 (69%) completed 5 or more starts. Eight horses (13%) failed to start and/or complete 5 or more races due to a recurrence of tendinitis. Six (10%) horses did not start and/or complete 5 or more starts for reasons unrelated to tendinitis and 5 (8%) horses were lost to follow-up. The median time between surgery and the first post operative start was 39 weeks. Fifty-seven per cent of those horses to start after surgery completed 20 or more starts and 40% raced on 40 or more occasions. Of the 42 horses to complete 5 or more races, the median number of post operative starts was 37 at time of follow-up. Thirty-two of 50 (64%) horses to start after surgery established or lowered lifetime racemarks. Thirty-six horses had raced prior to surgery. Thirty-one of 36 (86%) horses returned to racing after treatment of SDF tendinitis with accessory desmotomy (AD) and 27 horses (75%) completed 5 or more starts. Median earnings per start decreased 25% after surgery. Twenty-five horses had not raced prior to surgery. Nineteen (76%) horses in this group were age 2 years at time of injury. Nineteen of 25 (76%) horses started after surgery and 15 horses (60%) completed 5 or more starts.

Horses that had not started prior to sustaining injury had significantly (P<0.05) less total earnings per horse and earnings per start after surgery than those horses that had previously raced. Horses that had started before surgery achieved significantly faster post operative lifetime racemarks than horses that had not raced before surgery. Horses that were age 2 years at time of injury did not differ statistically from horses older than 2 years in any post operative variable evaluated. There was no statistical difference in rate of recurrence of tendinitis between horses undergoing AD in one or both limbs for treatment of tendinitis occurring in one limb. This study suggests that transection of the AL-SDF allows a high percentage of Standardbred horses with tendinitis to race and earn money without recurrence of tendinous injury. Horses that have not raced prior to tendinous injury may be expected to earn less money and achieve lower lifetime racemarks after surgery than horses that have raced prior to sustaining tendinous injury.