MRI and CT diagnosis of acute desmopathy of the lateral collateral sesmoidean (navicular) ligament and long-term outcome in a horse.
Authors: Kofler J, Kneissl S, Malleczek D
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Acute injuries to the lateral collateral sesamoidean ligament (CSL) are notoriously difficult to diagnose through conventional means, as demonstrated in this case of a 13-year-old Hanoverian mare presenting with severe forelimb lameness (grade 5/6) and coffin joint effusion that yielded no findings on radiography or ultrasonography despite a positive response to palmar digital nerve block. MRI proved essential for identifying the CSL damage and associated bone marrow oedema in the navicular bone, whilst CT was superior for visualising the focal bone defect at the ligament's insertion point—highlighting the complementary diagnostic value of advanced imaging modalities in obscure lameness cases. Conservative management comprising four weeks of complete box rest in a fibreglass cast followed by controlled rehabilitation resulted in a favourable long-term prognosis, with the mare sound at trot within three months and fully recovered by six months. For equine practitioners, this case underscores the importance of progressing to MRI and CT when conventional imaging fails to explain clinical signs localised to the distal interphalangeal region, and demonstrates that acute CSL injuries may respond well to strict rest protocols even when initial presentation suggests severe compromise. These findings are particularly relevant for farriers and physiotherapists involved in rehabilitation, as they provide evidence that structured immobilisation followed by gradual mobilisation can facilitate healing in this previously poorly characterised injury.
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Practical Takeaways
- •When radiographs and ultrasound fail to explain severe coffin joint lameness despite positive nerve blocks, MRI should be pursued as it can reveal soft tissue ligament injuries missed by conventional imaging
- •CT provides superior visualization of small bone defects at ligament insertion sites and complements MRI findings in navicular region pathology
- •Conservative management with extended box rest and cast immobilization can achieve full recovery in acute collateral sesamoidean ligament injuries, offering an alternative to aggressive intervention
Key Findings
- •MRI effectively demonstrated lateral collateral sesamoidean ligament damage and navicular bone marrow oedema in a lame horse where radiography and ultrasonography were inconclusive
- •CT imaging best visualized the focal bone defect of the navicular bone at the ligament insertion zone
- •Complete box rest with fibreglass cast for four weeks followed by controlled exercise resulted in full recovery within six months and return to soundness at trot by three months