Postoperative racing performance in standardbreds and thoroughbreds with osteochondrosis of the tarsocrural joint: 109 cases (1984-1990).

Medical records for 64 Thoroughbred and 45 Standardbred horses with osteochondrosis dissecans (OCD) of the tarsocrural joint that were treated by means of arthroscopic removal of the fragments before 2 years of age and before beginning racing were reviewed. Lesion site was recorded for all horses. The other foals from the dams of these surgically treated horses (siblings) were identified from mare progeny records. Racing data, including number of starts and money won during the 2- and 3-year-old racing years were obtained from the Jockey Club and the United States Trotting Association for affected horses and their siblings. Statistical analysis was performed to test the hypothesis that there was no difference between the racing performance of horses with OCD of the tarsocrural joint that were surgically treated by means of arthroscopic removal of the fragments prior to racing and that of their siblings. One hundred and seventy-four lesions were recorded in 109 horses. The distribution of lesions was similar to that previously reported. For the Standardbreds, 22% of those that had surgery raced as 2 year olds and 43% raced as 3 year olds, compared with 42 and 50% of the siblings that raced as 2 year olds and 3 year olds, respectively. For the Thoroughbreds, 43% of those that had surgery raced as 2 year olds and 78% raced as 3 year olds, compared with 48% and 73% of the siblings that raced as 2 year olds and 3 year olds, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)