A comparison of subjective and quantitative methods for detection of physitis in Thoroughbred foals.

The study is about comparing subjective and measurable methods for detecting the swelling (physitis) of particular bones (distal third metacarpal and metatarsal) in Thoroughbred foals, and concludes that using calculations from digitised images have potential as a diagnostic tool.

Research Objectives

• The main objective of the research was to compare subjective (based on observation) and computational methods of assessing the swelling of the distal third metacarpal (Mc3) and metatarsal (Mt3) bones of Thoroughbred foals. This condition of bone swelling is known as physitis.
• The study aimed to determine whether a more objective, computational method could provide accurate diagnostic information for this condition.

Methods

• In the process of the study, the lower leg portion (fetlocks) of 16 Thoroughbred foals were filmed on five different occasions over a 5-month period.
• The video images from the filming were transferred to computer and then digitised. This digitisation process is usually done to convert the video data into a form that can be processed by a computer.
• A key part of the study was the determination of the rate of change of each of the medial and lateral contours of the distal Mc3 and Mt3 bones. This was achieved by calculating values for the second derivative of the contour. The second derivative here refers to a mathematical measure that showcases the rate of change of a rate of change.
• Additionally, the subjective assessment of the degree of physeal swelling also took place. This was done by assigning a grade according to an ordinal scale of severity.

Results

• The results of the study showed that the second derivative values for sites with slight to distinct physitis (Grade >/=1.5) were significantly higher than the second derivative values for the sites with no apparent physitis (Grade 0), with a level of significance of p=0.001.

Conclusions

• The research concludes that the second derivative of the contour of a limb has potential to be used as a diagnostic tool for the quantitative detection of physitis.
• In other words, a mathematical interpretation of a digitised image could serve as a more objective way of diagnosing this condition, thus eliminating or minimizing the margin of error that comes with the subjective observation.