Proximodorsal first phalanx osteochondral chip fragmentation in 336 horses.

This study analyzed the effectiveness of arthroscopic surgery in treating osteochondral fragmentation in the first phalanx of horses, and how other fetlock joint injuries affected their recovery. The study showed a significant correlation between the type of lesion and the Thoroughbred’s return to racing but no meaningful link in return to previous use for racehorses versus non-racehorses, single versus multiple joint involvement, and single versus multiple fragmentations per joint.

Understanding the problem

• In this study, the researchers looked at the effects of arthroscopic surgery on 336 horses suffering from osteochondral fragmentation. Osteochondral fragmentation is a joint condition where pieces of cartilage or bone (or both) within a joint break off, causing pain and inflammation. The problem area focused on in this study is the proximodorsal aspect of the first phalanx, part of the horse’s leg.
• In addition to exploring the outcomes of surgery for the osteochondral fragmentation, the study also examined the influence of other fetlock (a joint similar to a human ankle) joint lesions on the prognosis for the horses.

Research group classification

• The horses were divided into three groups based on their recovery outcomes. The first group consisted of horses who were able to return to their previous use and maintain or improve the same level of performance. The second group included horses who were able to return to their previous use but not necessarily at the same performance level. And the third group was made up of horses that could not return to their previous use.

Results and findings

• The study showed that among the 336 horses, 96 horses had only fragmentation, 140 had fragmentation along with other fetlock injuries, and 100 underwent concurrent carpal arthroscopy (surgery that looks inside a joint with a small camera). Of the 100 horses that underwent carpal arthroscopy, some had only first phalanx fragmentation while others had other associated fetlock injuries.
• Interestingly, there was a significant relationship between the type of injury (or lesion) and return to previous use specifically for the Thoroughbred racehorse group. In other words, the kind of injury a Thoroughbred racehorse had significantly affected their likelihood to return to racing. The more serious the injury, the less likely the horse was able to return to its previous racing performance level.
• On the other hand, the study found no significant relationship between racehorses and non-racehorses’ return to previous use, single versus multiple joint involvement, and single versus multiple fragmentations per joint.
• This suggests that Thoroughbred racehorses may be particularly sensitive to additional fetlock or carpal injuries, as demonstrated by the type of lesion significantly impacting the outcome.