Metacarpophalangeal joint injury patterns on magnetic resonance imaging: A comparison in racing Standardbreds and Thoroughbreds.

This study compared the magnetic resonance imaging findings of the metacarpophalangeal joint in two types of racing horses, Standardbreds and Thoroughbreds. The report suggested that each breed experiences different injury patterns and levels of severity, with Thoroughbreds more likely to develop stress fractures and metacarpophalangeal joint injuries being common in both breeds.

Introduction

• The research focuses on the metacarpophalangeal joint of racing horses, a known common location of arthropathy due to overuse.
• Both Standardbreds and Thoroughbreds – two different breeds of racehorses – were included in the study.
• The study was conducted retrospectively, using data from June 2010 to February 2016. The study aimed to understand and compare breed-based differences in metacarpophalangeal injuries.

Methodology

• Researchers fetched and reviewed images from the Clinique Vétérinaire Equine de Chantilly and Imavet data archives.
• The study sample included a total of 107 horses: 30 Standardbreds and 77 Thoroughbreds. One reader reviewed all images.
• A system of semiquantitative scores was used to evaluate and compare the MRI findings for each breed.

Findings

• Thoroughbreds had a higher incidence of stress fractures (40.3% compared to 10% in Standardbreds).
• Overall, Thoroughbreds showed more severe scores of subchondral sclerosis and bone marrow lesions than Standardbreds.
• On the other hand, Standardbreds had more instances of subchondral bone defect and resorption. They also had higher synovitis and joint capsule thickening scores.
• Subchondral lesions occurring in multiple locations were common in both breeds. These were not confined only to the distal palmar condyle.
• Dorsomedial joint pole subchondral injuries were more prevalent in Standardbreds.
• Both breeds had a high rate of periarticular soft tissue injuries (36.7% in Standardbreds and 20.8% in Thoroughbreds). However, these were rarely considered as the main causes of lameness.

Conclusion

• This study highlighted the variability in injury patterns between the two breeds of racehorses.
• Though both breeds showed a high prevalence of joint injuries, the types and severity of injuries differed between them.
• Findings also validated the importance of using low-field MRI as a tool to assess potential whole-organ injuries in racehorses.