Slab fractures of the third carpal bone in standardbreds and thoroughbreds: 155 cases (1977-1984).

This research investigates third carpal bone (C3) slab fractures in two breeds of racing horses, Standardbreds and Thoroughbreds, and it analyzes treatment methods, post-injury performance and the factors influencing those. Overall, the study included 155 cases.

Methodology and Case Distribution

• The study involves a retrospective review of case records and radiographs of 155 horses diagnosed with third carpal bone slab fractures.
• Race records of 72 Thoroughbreds and 61 Standardbreds were used for the performance analysis.
• Performance criteria examined included the ability to participate in 1 race, the ability to participate in 10 races or earn $2,000 within 1 year after the fracture, and earnings per race.
• The treatment methods used (lag screw fixation, fragment excision, or rest) were consistent across both breeds.

Findings and Results

• In Thoroughbreds, the right third carpal bone was more likely to be affected by fractures whereas in Standardbreds, fractures occurred equally in both front limbs.
• The dorsomedial aspect of the third carpal bone was the most common fracture location in 87% of the cases.
• The age and sex distributions were different between the two breeds. Two-year-old Standardbreds and three-year-old Thoroughbreds were most often referred for treatment.
• Females in both breeds were less likely to race again after the injury compared to their male counterparts.
• Interestingly, all 38 Standardbreds with prior racing experience could race again after the fracture. This past experience had no influence on the recovery of Thoroughbreds.

Treatment Effects and Outcome

• The type of treatment didn’t significantly impact the outcome, meaning no one treatment method was more successful than the others.
• The characteristics of the fracture did not significantly influence the outcome. However, they did affect the choice of treatment.
• Convalescent time, or recovery time, was not found to be related to any of the variables examined in the study or related to the outcome. The average time from admission to first race was 11 months.
• A majority of horses, regardless of breed, could race again; 77% of Standardbreds and 65% of Thoroughbreds did so.
• After the fracture, earnings per race decreased in both breeds. This decline was more pronounced in Thoroughbreds.