Associate Professor University of Illinois Urbana, Illinois
Periarticular osteophytes of the distal tarsus are commonly recognized as a radiographic hallmark of degenerative joint disease (DJD); however, they have also been reported in non-lame yearling horses on routine pre-sale radiographs. This finding in yearling Quarter Horses has been associated with poorer performance, but effects in Standardbreds have not been investigated. The purpose of this study was to identify the radiographic prevalence of periarticular osteophytes of the distal tarsus in non-lame yearling Standardbred horses and to evaluate potential impact on race performance. We hypothesized that larger osteophytes would have a significantly negative impact on race performance. Of 416 Standardbred yearlings from a single farm, 113 had distal tarsal periarticular osteophytes. Osteophytes were measured on radiographs and categorized based on size. Racing records of horses with and without osteophytes were obtained from the United States Trotting Association. Regression analysis revealed no association between the presence of periarticular osteophytes and performance parameters. Within the affected group, osteophyte size was not associated with performance parameters. These data suggest that in non-lame yearling Standardbreds, periarticular osteophytes of the distal tarsus are an incidental finding. This difference from Quarter Horses may be a result of the type of activity required of the different breeds. Limitations of this study include the relatively small number of affected individuals and the subjective nature of measurements. Other factors playing a role in race performance could not be accounted for. In conclusion, distal tarsal periarticular osteophytes in young, non-lame Standardbred horses should not adversely affect racing potential.
