Non-weight bearing ultrasonographic examination allows the diagnosis of longitudinal fiber disruption (split) in equine suspensory ligament branches not visible on weight bearing examination.
Authors: N. Werpy, Kristina Chapman, L. Griffith
Journal: Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association
Summary
Suspensory ligament branch splits represent a diagnostic challenge in equine practice, with MRI frequently detecting pathology that remains subtle or invisible on conventional weight-bearing ultrasonography. Werpy and colleagues performed a retrospective case series examining 62 suspensory ligament branches from 37 horses using both weight-bearing and non-weight-bearing ultrasonographic positions, defining splits as linear hypoechoic regions that enlarged and became anechoic when the limb was unloaded. The cohort included 14 partial splits, 11 intrasubstance splits, and 14 complete splits (two with synovial involvement), demonstrating that non-weight-bearing imaging significantly improved lesion visibility and allowed more accurate assessment of severity compared to traditional weight-bearing examination. Follow-up scans in eight horses (up to 14 months post-diagnosis) showed variable outcomes: two branches remained unchanged, five improved partially, and one resolved completely. For practitioners, this work suggests that non-weight-bearing ultrasonography should become standard protocol when suspensory branch pathology is suspected, particularly when weight-bearing images appear inconclusive or when MRI findings don't correlate with clinical signs—though a prospective longitudinal study is needed to establish the prognostic significance of these lesions and their relationship to clinical outcomes.
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Practical Takeaways
- •Always perform non-weight bearing ultrasound examination of suspensory ligament branches alongside weight bearing images to avoid missing or underestimating split lesions.
- •Non-weight bearing positioning increases lesion visibility and allows for more accurate grading of split severity, which is important for prognostic counseling and monitoring response to treatment.
- •Some suspensory ligament branch splits show spontaneous improvement or resolution over time, but longitudinal studies are needed to establish which lesions have clinical significance and warrant intervention.
Key Findings
- •Non-weight bearing ultrasonographic examination revealed suspensory ligament branch splits that were not visible or were less conspicuous on weight bearing images in 62 branches from 37 horses.
- •Of the 39 splits identified, 14 were complete splits (36%), 14 were partial splits (36%), and 11 were intrasubstance splits (28%), with 2 complete splits showing extension of synovial fluid and membrane.
- •Recheck ultrasound in 8 horses up to 14 months post-diagnosis showed persistence in 2 horses (25%), partial resolution in 5 horses (62.5%), and complete resolution in 1 horse (12.5%).