Diagnosis and outcome following tenoscopic surgery of the digital flexor tendon sheath in German sports and pleasure horses.
Authors: Cender Andrea N, Mählmann Kathrin, Ehrle Anna, Merle Roswita, Pieper Laura, Lischer Christoph J
Journal: Equine veterinary journal
Summary
# Nonseptic Digital Flexor Tendon Sheath Pathology: What Tenoscopy Reveals and What to Expect Digital flexor tendon sheath tenosynovitis remains a significant source of lameness in horses, yet the specific lesion patterns and post-operative outcomes have been poorly characterised in large clinical populations. This retrospective analysis of 145 limbs (131 horses) undergoing tenoscopic surgery between 2011 and 2020 identified multiple pathologies: deep and superficial digital flexor tendon (DDFT and SDFT) lesions occurred with similar frequency (55 limbs each), whilst palmar/plantar annular ligament (PAL) constriction was the most prevalent finding (99 limbs), with 75% of cases presenting as multi-structure involvement rather than isolated lesions. Ultrasonography and contrast tenography proved complementary diagnostic tools, with tenography demonstrating superior sensitivity for manica flexoria (89%) and DDFT tears (72%) but lower specificity, whereas ultrasonography offered excellent specificity (92–94% across structures) with moderate sensitivity—a critical distinction when planning imaging protocols. Post-operatively, approximately half of horses (50.8%) returned to their previous level of performance, though this outcome was substantially worse for DDFT lesions alone (36.6% success rate), whilst 33.8% continued at reduced capacity and 15.3% remained chronically lame. For practitioners, these findings emphasise that multi-modal imaging optimises diagnostic accuracy, that PAL involvement is common and warrants specific assessment, and that realistic prognostic counselling—particularly regarding isolated DDFT pathology—should acknowledge that surgery offers meaningful functional recovery in only a proportion of cases.
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Practical Takeaways
- •Use both ultrasonography and contrast tenography complementarily for diagnosis—ultrasound is highly specific but tenography catches more cases, particularly for manica flexoria and DDFT tears
- •Manage owner expectations carefully: only 51% of horses fully return to preinjury work, and DDFT injuries carry significantly poorer prognoses
- •Multi-structure involvement in the DFTS is the norm rather than exception (75% of cases), so thorough diagnostic imaging and complete surgical evaluation are essential
Key Findings
- •Combination lesions were most common (109/145 limbs), with SDFT lesion plus PAL constriction being the most frequent combination
- •Contrast tenography was more sensitive than ultrasonography for MF (89% vs 64%) and DDFT tears (72% vs 54%), while ultrasonography was more specific for all three structures
- •Following tenoscopic surgery, 50.8% of horses returned to same or higher exercise level, 33.8% performed at reduced level, and 15.3% remained chronically lame
- •DDFT lesions had poorest prognosis with only 36.6% returning to preinjury exercise level