Improved radiological diagnosis of palmar osteochondral disease in the Thoroughbred racehorse.

This study aimed to enhance the accuracy of diagnosing Palmar Osteochondral Disease (POD), a frequent condition in Thoroughbred racehorses, through radiography. Diagnosis improvement techniques included the creation of radiology training manual to ensure the identification of primary and secondary radiological features related to POD.

Objective of the Study

• The research’s primary purpose was to improve the accuracy of diagnosing Palmar Osteochondral Disease (POD) in Thoroughbred racehorses through radiographs.

Methodology

• The study is a prospective, longitudinal study that involved taking radiographs in nine different projections of the metacarpophalangeal joints (MCPJ) of 50 Thoroughbreds.
• Afterward, the researchers dissected the MCPJs, and a clinician scored their gross pathology.
• Three experienced Thoroughbred clinicians each read the radiographs and recorded their findings.
• Another clinician compared each radiograph with the related gross specimens to link radiological findings with joint pathology. This expert assessment is referred to as the ‘gold standard’.
• After the identification of radiological features associated with POD, the clinicians were presented with a training manual. They then reassessed their ability to diagnose POD by re-reading the radiographs.

Results

• POD was a prevalent condition, found in 88 out of 100 joints.
• The initial sensitivity and specificity levels of the three clinicians in diagnosing POD were relatively low, averaging at 0.37 and 0.75, respectively. Conversely, the ‘gold standard’ demonstrated a high sensitivity and specificity of 0.95 and 1.0 respectively.
• POD was associated with both primary radiological features such as focal radiolucencies in the palmar condyles, disruption of the outline of subchondral bone, and focal sclerosis of the palmar condyles, and secondary features such as basilar and apical osteophytes on the proximal sesamoid bones, flattening of the palmar condyles and cavitation of the dorso-distal aspect of the third metacarpal bone.
• The secondary radiographic features were easier to identify. After the training, the clinicians’ performance in recognizing POD significantly improved.

Conclusions

• Despite the potential limitations including the small number of participating clinicians and a low proportion of POD negative cases in the study, it was found that clinicians often overlook key radiological features related to POD.
• The training manual designed to alert clinicians to relevant radiological features significantly improved the sensitivity and accuracy of the diagnosis.