Radiographic evaluation of the width of the femorotibial joint space in horses.

The research article discusses a study designed to measure and compare the minimal joint space width (mJSW) in radiographic images of femorotibial joints of horses, and finding the optimal angle for capturing these images. The study found that the measurements were most accurate at a 10-degree angle from the horizontal, providing valuable information for the diagnosis and treatment of osteoarthritis in horses.

Research Method and Participants

• The study involved 12 healthy mares, with 22 femorotibial joints evaluated in total, along with 3 equine cadavers, allowing for the evaluation of further 6 stifle joints.
• To assess the mJSW, radiographic views of the joints were recorded at different angles (5°, 10°, and 15°) in both the proximodistal and lateromedial planes. The literature identifies these areas as commonly affected by disorders like osteoarthritis in horses.
• Two evaluators manually measured the mJSW, and these results were compared with measurements made by a digital analysis software program developed for humans.
• The researchers assessed the interevaluator reproducibility, that is, the consistency of the measurements across different evaluators. This is crucial to validate the measurement protocol.

Results and Findings

• The study found close agreement between the measurements made by the two raters, as well as between a veterinary radiologist and the analysis software. This supports the reliability of the measurement procedures used.
• The angle at which the radiographic view was taken significantly influenced the measurements of the mJSW in the medial compartment (inside part) of the femorotibial joint. However, this was not the case for the lateromedial plane.
• In terms of the ideal angle for mJSW measurement, the study found that a 10-degree angle from the horizontal yielded significantly larger measurements for the medial compartment.
• There was no significant difference for the mJSW in the lateral compartment (outside part) across different angles.
• Finally, automated measurements of the mJSW in the medial compartment closely matched the thickness of nonmineralized cartilage as depicted in histologic preparations of associated tissues, providing further validation of the measurements.

Conclusions and Implications

• The study identified a 10-degree caudoproximal-craniodistal oblique angle as the optimal radiographic projection for measuring mJSW in the medial compartment of femorotibial joints in horses.
• This finding can significantly enhance the diagnostic and treatment strategies for conditions such as osteoarthritis, which is a common affliction in horses.
• The consistent results among different methods and evaluators reinforce the reproducibility and accuracy of the measurements, supporting the use of this measurement protocol in veterinary practices.