Answer – Myth
In a recently published article, researchers looked at stifle and hock OCD lesions in thoroughbred weanlings/yearlings to determine if surgery had an impact on future racing performance. Owners of thoroughbred weanlings and yearlings will have radiographs taken prior to the yearling sales, offering them the opportunity to diagnose OCD lesions in these young horses prior to the time that clinical symptoms are shown. The decision is then made as to whether to address these lesions surgically. Researchers identified 37 thoroughbred horses with stifle OCD and 35 with hock OCD as part of their retrospective study. They looked at each horse’s performance through their 2- and 3- year old racing careers and compared them with matched controls, using measurements such as number of race starts, wins, places and prize money earned, etc. The effect of the horse’ age at the time of surgery and the experience of the surgeon were also taken into account when looking at the outcome for those horses identified with stifle OCD. Their results showed that stifle OCD had a negative effect on performance when compared to the matched control and that those horses with hock OCD made fewer starts than those control horses. The younger the age of the horse at the time of surgery and a lesser-experienced surgeon were also associated with worse outcomes for stifle OCD.
So what does this mean? We know that there is evidence to suggest that OCD lesions in the stifle joint can reattach for up to 12 months after birth. This study suggests that surgery may not be necessary in many of these very young horses and that a “wait and see approach” could be a better option for horses less than a year of age. Nonsurgical management (simple confinement, for example) can be very successful especially in cases where the OCD fragment is still attached. It is still important to diagnose these horses, understanding that good veterinary care and communication are very important in setting up a treatment plan for those horses diagnosed with OCD to insure the best possible outcome.
Scientific Article: Clarke KL, Reardon R, Russell T. “Treatment of Osteochonrosis Dissecans in the Stifle and Tarsus of Juvenile Thoroughbred Horses.” Veterinary Surgery 2014. Online access Sept. 22, 2014.
Companion Article: Oke, S. “Delay OCD Surgery for Optimal Racehorse Performance.” TheHorse.com, December 10, 2014, article #34987.