Response to injection of the navicular bursa with corticosteroid and hyaluronan following high-field magnetic resonance imaging in horses with signs of navicular syndrome: 101 cases (2000-2008).
Authors: Marsh, Schneider, Sampson, Roberts
Journal: Journal of the American Veterinary Medical Association
Summary
# Editorial Summary Marsh and colleagues reviewed 101 horses treated with corticosteroid and hyaluronan injection into the navicular bursa between 2000 and 2008, using pre-treatment high-field MRI findings to stratify outcomes and identify which pathological changes responded favourably to this intervention. Overall, 75% of horses returned to their intended use (for an average of 9.66 months) and 35% were sound at follow-up, but success was significantly influenced by two critical factors: lameness duration and the specific MRI-identified pathology. Horses lame for less than six months before treatment demonstrated substantially better outcomes—both in terms of returning to work and remaining sound—compared with those presenting with chronic lameness histories. Notably, primary deep digital flexor (DDF) tendonitis showed the strongest response to bursal injection combined with rest and rehabilitation, whereas horses with scar tissue in the proximal bursa, DDF-to-navicular bone adhesions, or multiple concurrent abnormalities had markedly poorer prognoses. For equine practitioners, these findings underscore the importance of early intervention in suspected navicular disease and highlight that MRI-guided diagnosis can help identify which horses are realistic candidates for conservative bursal therapy versus those requiring alternative management strategies or more guarded long-term expectations.
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Practical Takeaways
- •Early intervention matters: horses lame for less than 6 months have significantly better outcomes with navicular bursa injection, so early diagnosis and treatment are critical
- •MRI findings predict success: horses with primary DDF tendonitis respond best, while those with scar tissue, adhesions, or multiple pathologies should have realistic expectations about treatment outcomes
- •Set client expectations appropriately: while 75% return to work, only 35% are sound long-term, and outcomes vary substantially based on underlying pathology
Key Findings
- •75% of horses returned to intended use following navicular bursa injection with corticosteroid and hyaluronan, with mean positive response of 9.66 months
- •Horses lame for <6 months before treatment were significantly more likely to return to use, have longer positive response, and be sound at follow-up compared to those with longer lameness duration
- •Primary DDF tendonitis responded best to treatment, followed by navicular bursitis, while scar tissue, adhesions, and multiple abnormalities showed poor response
- •Treatment response was dependent on specific pathological changes detected on MRI and pre-treatment lameness duration