Catastrophic scapular fractures in Californian racehorses: pathology, morphometry and bone density.

The article explores and gains a deeper understanding of scapular fractures in racehorses, emphasizing the common fracture configuration and its link to prior stress modifications to the bone. This study used visual and computed tomography (CT) examinations on collected post mortem scapulae to analyze their structure and density. The findings reveal a pattern of stress-related fracture configuration, pointing out potential for preventative measures if detected early.

Methods Used in The Research

• The researchers collected and analyzed both fractured and intact scapulae from deceased Thoroughbred and Quarter Horse racehorses.
• These bones were examined visually, as well as using computed tomography (CT), a method that produces detailed and sectional images of the body.
• The team recorded the fracture configuration, changes in bone structure, and standardized CT measurements of the scapulae’s shape and density.
• Statistical comparisons were conducted between fractured, non-fractured contralateral (occurring on the opposing side), and control scapulae to note any significant differences.

Findings of the Study

• Thirty-nine scapulae from 20 racehorses were obtained and all 14 fractured scapulae had a similar, comminuted (made up of several fragments) fracture configuration.
• The horse’s fractures went through the neck of the scapula, and the distal fragment was primarily split into two major fragments by a fracture in the frontal plane that entered the glenoid cavity.
• All fractured and intact contralateral scapulae showed signs of periosteal (outer layer of bone) proliferation and/or radiolucency in the area furthest from the centre of the scapular spine. This was less common in the non-fractured scapulae of horses without a scapular fracture.
• Fractured scapulae had a lower mean density and significantly greater density heterogeneity in the spine region adjacent to the transverse fracture compared to the control scapulae.

Conclusions from the Study

• Thoroughbred and Quarter Horse racehorses have a characteristic scapular fracture pattern linked with a pre-existing pathology of the spine’s distal aspect.
• This fracture pattern aligns with the stress fractures commonly diagnosed in lame Thoroughbred racehorses.
• The catastrophic fractures are the acute manifestation of a more chronic process, meaning these fractures are not sudden, but the result of a more long-term condition.
• This study provides potential for early detection and prevention of fatalities by monitoring the mentioned stress points and abnormalities.