A 10-year study of arthroscopic surgery in racing Thoroughbreds and Quarterhorses with osteochondral fragmentation of the carpus.

Abstract

BACKGROUND\nOsteochondral fragmentation of the carpus is a common cause of lameness in racehorses. Prognosis following arthroscopic removal of the fragments was reported in 1987, but little is known of recent success rates.\n\n\nOBJECTIVE\nTo identify associations between the severity and location of osteochondral fragments in the carpus, and to describe the racing performance of horses pre- and post-surgery in Thoroughbreds and Quarterhorses. To identify factors associated with a horse racing post-surgery.\n\n\nSTUDY DESIGN\nRetrospective study of clinical records (2006 to 2016).\n\n\nMETHODS\nSurgical and racing records for racehorses undergoing arthroscopic surgery of the carpus were collated during the 10-year study period. Signalment, location of osteochondral fragmentation and grade of defect left after removal and debridement identified and racing performance pre- and post-surgery were described, stratified by breed. Logistic regression analysis was used to identify factors associated with unsuccessful return to racing.\n\n\nRESULTS\nIn total, 828 horses (n = 416 Quarterhorses; n = 412 Thoroughbreds) underwent 880 carpal arthroscopies after fragments were found on radiography. Sixty-five percent (n = 289) and 27% (n = 118) of the lesions were bilateral in Quarterhorses and Thoroughbreds respectively (P<0.001). In both breeds, the most commonly affected bone was the dorsodistal radial carpal bone (n = 320/659; 48.6%). Overall, 82% (n = 686; n = 358 Quarterhorses, n = 328 Thoroughbreds) of horses raced post-surgery, with 69.5% (n = 476; n = 228 Quarterhorses, n = 248 Thoroughbreds) racing at the same or a higher level of competition. Factors associated with horses not returning to racing post-surgery were increasing horse age, female horses, and a lesion grade of 4, while racing pre-surgery was protective.\n\n\nMAIN LIMITATIONS\nThis study does not include a control population for comparison.\n\n\nCONCLUSIONS\nThere were significant differences between the location and severity of lesions in Quarterhorses, when compared to Thoroughbreds. The majority of horses return to racing following surgery, although performance was influenced by lesion severity. This article is protected by copyright. All rights reserved.