Magnetic resonance imaging-detected adaptation and pathology in the distal condyles of the third metacarpus, associated with lateral condylar fracture in Thoroughbred racehorses.

This study examines how magnetic resonance imaging (MRI) can monitor changes in bones and cartilage, potentially predicting fractures in the third metacarpus bone in Thoroughbred racehorses. It reveals that there’s typically more bone and cartilage adaptation or damage in horses that had fractures in this bone, and suggests regular monitoring could help avoid catastrophic breaks.

Objective and Methodology

• The research aimed to examine the use of MRI in detecting bone and cartilage changes in thoroughbred racehorses’ third metacarpus bone (McIII), particularly focusing on identifying signs that could indicate a likelihood of lateral condylar (LC) fractures. There were two explicit objectives: to discover if there was more damage or adaptation in horses with fractured McIIIs and to determine if horses with previous LC fractures possessed more noticeable changes in their McIIIs.
• The study involved 96 horses that were euthanized at racecourses. The McIIIs from these horses were divided into three categories: bones from horses with no history of LC fractures, non-fractured bones from horses with a past LC fracture, and fractured bones from horses with history of LC fractures.
• The MRIs of these bones were studied and scored based on their bone and cartilage changes.

Findings

• The research revealed that 9% of bones from horses without past LC fractures and 11% from horse with a previous unilateral LC fracture had incomplete LC fractures. The rate of bone and/or cartilage anomalies tended to rise from group 1 (no history of LC fractures) to Group 3 (fractured bones from horses with LC fractures).
• Interestingly, focal palmar necrosis, a type of bone degeneration, was most commonly found in bones from horses without LC fracture history. And some form of pathology was more observed in the bones from Group 2.

Conclusions

• The study demonstrated the potential feasibility of using MRI to detect bone and cartilage changes associated with lateral condylar fractures. However, there was no significant difference discovered in the amount of these changes between bones from horses without LC fractures and those with one LC fracture.
• The findings established a call for periodic monitoring of bone and/or cartilage changes in racehorses’ McIII to potentially forecast and prevent disastrous LC fractures.