Risk assessment for condylar stress fracture in elite racing Thoroughbreds using standing computed tomography-based...

Area of Science:

• Equine orthopedics
• Biomechanics
• Veterinary radiology

Background:

• Condylar stress fractures of the third metacarpal bone (MC3) are common in Thoroughbred racehorses, linked to parasagittal groove (PSG) subchondral bone injury (SBI).
• Standing computed tomography (sCT) detects early SBI, but objective methods for identifying high-risk horses are lacking.

Purpose of the Study:

• To estimate PSG first principal strain in Thoroughbred racehorses using sCT screening.
• To compare finite element (FE) analysis strain predictions with subjective clinical risk assessments.

Main Methods:

• Retrospective study using sCT images from nine thoracic limbs of seven Thoroughbred racehorses.
• A validated 3D finite element (FE) analysis estimated PSG first principal strain in the distal MC3.
• FE results were compared with subjective risk assessment by Racing Victoria.

Main Results:

• MC3 condyles with PSG SBI showed significantly higher first principal strain compared to unaffected condyles.
• Focal strain concentrations were identified at SBI locations.
• FE-predicted strain elevation and clinical risk assessment showed concordance (R² = 0.62).

Conclusions:

• 3D FE analysis shows potential for objective assessment of MC3 condylar stress fracture risk in racehorses.
• Further automation of the FE analysis pipeline is needed for clinical relevance.
• Current sCT screening and FE analysis demonstrate concordance in risk assessment.