Association of catastrophic condylar fracture with bony changes of the third metacarpal bone identified by use of standing magnetic resonance imaging in forelimbs from cadavers of Thoroughbred racehorses in the United States.

This study used standing magnetic resonance imaging (MRI) to compare bone changes in the third metacarpal bone (MC3) of Thoroughbred racehorse cadavers. The researchers found that there’s a significantly higher degree of bone changes, including bone marrow lesions and increased dense bone volume percentage, in horses with a catastrophic condylar fracture compared to those without.

Research Procedure

The research involved the following procedures:

• The research used 140 forelimbs from 26 case horses (horses with both forelimbs) and 88 control horses (horses with a single forelimb).
• The team identified Bone marrow lesions (BMLs) as a decrease in T1-weighted (T1W) signal and increases in T2*-weighted (T2*W) and short tau inversion recovery (STIR) signals. They also identified dense bone volume percentage (DBVP) as decreases in T1W, T2*W, and STIR signals. These were recorded in the distopalmar aspect of MC3.
• The researchers made a comparison between fractured and nonfractured limbs of cases, as well as between fractured limbs of cases and randomly selected limbs of controls.

Research Findings

The key findings of the research include:

• All the fractured limbs of the case horses had BMLs. This was significantly higher than the nonfractured limbs in the same group, which represented only 27%.
• There was a significant difference when comparing the BMLs in fractured limbs of cases (100%) against limbs of controls (7%).
• There was no significant difference in DBVP between fractured and non-fractured limbs in lateral or medial condyles among the case horses.
• However, fractured limbs of case horses had significantly greater DBVP in lateral and medial condyles compared to limbs of control horses.

Conclusion and Clinical Relevance

This study demonstrated that standing MRI revealed a significantly greater degree of bone change in racehorses with condylar fracture when comparing fractured and nonfractured limbs of case horses and fractured limbs of case horses with randomly selected limbs of control horses. Therefore, this advanced imaging technique is beneficial in detecting bone changes that may potentially lead to catastrophic injuries in horses, helping in early diagnosis and preventive measures.