Surgical treatment of dorsal cortical fractures of the third metacarpal bone in thoroughbred racehorses: 53 cases (1985-1989).

Between January 1985 and May 1989, 53 Thoroughbred horses (mean age 3.2 years) were surgically treated for dorsal cortical fractures of the third metacarpal bone (MC III). All horses were treated with cortical drilling through the fracture line (osteostixis). Diagnosis of the fractures was confirmed by xeroradiography. Lifetime racing records were obtained for all horses. Forty-seven horses returned to racing after surgery (89%). The mean time between surgery and the first race was 6.8 months. Horses had a mean of 10.9 starts before surgery and 16.1 starts after surgery. The mean earnings per start before surgery was $6,459 and after surgery was $5,685. Of the 47 horses that raced after surgery, 70% raced at the same class or improved. Complications related to surgery were seen in 10 horses. Two horses had a second fracture of MC III at the same site, and were again treated by osteostixis, after which both horses returned to competition. Fractured drill bits were left in the MC III of 4 horses. One of these horses had catastrophic failure of MC III. Two horses developed subcutaneous infections and 2 horses had catastrophic failure of MC III in the surgically treated limb. Osteostixis appears to be an effective treatment for returning horses affected with dorsal cortical fractures to racing.