Ultrasonographic scoring system for superficial digital flexor tendon injuries in horses: intra- and inter-rater variability.
Authors: Alzola Domingo Rafael, Riggs Chris M, Gardner David S, Freeman Sarah L
Journal: The Veterinary record
Summary
# Editorial Summary: Ultrasonographic Scoring for Superficial Digital Flexor Tendon Injuries Tendinopathy of the superficial digital flexor tendon (SDFT) remains a career-threatening injury in performance horses, yet quantifying lesion severity with consistency across clinicians has proven challenging. Alzola Domingo and colleagues developed a standardised ultrasonographic scoring system encompassing injury type, extent, location, echogenicity, cross-sectional area and longitudinal fibre pattern, then tested its reliability by having five clinicians independently assess ultrasound images from 14 affected Thoroughbreds (seven with core lesions, seven with diffuse lesions) and controls on two separate occasions. Core lesions demonstrated excellent inter-rater agreement across nearly all parameters (Kendall's coefficient ≥0.74), whilst diffuse lesions showed more variable results, with strong agreement for most measures but notably poor consensus on echogenicity assessment (coefficient=0.22); intra-rater reliability followed similar patterns, with reliable repeat scoring for lesion location and fibre pattern but moderate variability for cross-sectional area measurements in diffuse cases. Clinicians can confidently use this system to classify injury type and track structural changes within core lesions, though echogenicity assessment should be interpreted cautiously and diffuse lesion scoring benefits from experienced interpretation. Adoption of this validated framework will enable more rigorous longitudinal monitoring and allow meaningful comparison of injury progression across research studies, ultimately improving our ability to benchmark treatment outcomes and prognosis.
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Practical Takeaways
- •This scoring system allows veterinarians to reliably classify SDFT injuries and track lesion progression with confidence in core lesion cases, improving consistency in clinical records and treatment planning.
- •Echogenicity assessment shows poor inter-rater reliability and should not be relied upon as a primary diagnostic criterion; focus instead on lesion type, location, cross-sectional area, and fibre pattern.
- •Standardized ultrasonographic assessment using this validated system enables meaningful comparison of cases across different practices and time periods, improving research quality and clinical outcomes.
Key Findings
- •Type of injury (core vs. diffuse) achieved perfect inter- and intra-rater agreement, demonstrating reliable classification capability.
- •Core lesions showed very strong inter-rater agreement (KC ≥0.74) for all parameters except echogenicity, with intra-rater reliability (LC ≥0.73) similarly high.
- •Diffuse lesions demonstrated strong inter-rater agreement (KC ≥0.62) for most parameters but weak agreement for echogenicity (KC=0.22).
- •The validated ultrasonographic scoring system is reliable and repeatable for all parameters except echogenicity, facilitating standardized injury recording and meta-analyses.