Two clinical manifestations of desmopathy of the accessory ligament of the deep digital flexor tendon in the hindlimb of 23 horses.
Authors: Eliashar E, Dysont S J, Archer R M, Singer E R, Smith R K W
Journal: Equine veterinary journal
Summary
# Desmopathy of the Accessory Ligament of the Deep Digital Flexor Tendon in the Hindlimb Desmopathy affecting the accessory ligament of the deep digital flexor tendon (ALDDFT) in the hindlimb represents an underrecognised cause of equine lameness, prompting this retrospective review of 23 cases across three referral centres to characterise its clinical presentation, imaging findings and outcomes. The cohort comprised primarily cobs and native ponies (mean age 12 years) used for general riding or driving, with ultrasonographic evidence of ALDDFT enlargement that was either diffuse or localised to distinct regions of the ligament. Two distinct clinical phenotypes emerged: Group A (13 horses) presented with acute unilateral hindlimb lameness following traumatic injury, whilst Group B (10 horses) manifested postural abnormalities—notably knuckling and metatarsophalangeal joint semiflexion—with insidious or sudden onset. Management consisted of box-rest and graded exercise, with approximately half the cohort undergoing desmotomy or desmectomy; crucially, 73% of Group A horses returned to full function whilst only 10% of Group B achieved this outcome, indicating that postural changes confer a substantially worse prognosis. Practitioners should recognise that flexural deformity of the metatarsophalangeal joint warrants ultrasonographic evaluation of the ALDDFT as a primary differential diagnosis, and counsel owners that whilst traumatically induced desmopathy may resolve with appropriate rehabilitation, established postural abnormalities are likely irreversible.
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Practical Takeaways
- •Recognize ALDDFT desmopathy as a differential diagnosis for hindlimb lameness and especially for flexural deformities presenting with knuckling or semiflexion of the metatarsophalangeal joint
- •Prognosis differs markedly: acute traumatic injuries have good outcomes (73% return to work), but established postural changes are irreversible with poor prognosis (90% remain lame)
- •Ultrasonographic examination is essential for diagnosis, though lesions may be focal; conservative management (rest and controlled exercise) should be attempted first, with surgical intervention (desmotomy/desmectomy) reserved for selected cases
Key Findings
- •Two distinct clinical presentations of ALDDFT desmopathy were identified: acute traumatic lameness (Group A, 13 horses) and insidious/sudden postural abnormality (Group B, 10 horses)
- •73% of horses in Group A (acute lameness) returned to full function, while 90% of Group B horses (postural changes) remained lame
- •Enlargement of the ALDDFT was identified ultrasonographically in all 23 horses, with 44% showing abnormalities localized to part of the ligament
- •Treatment included box-rest and controlled exercise, with 10 horses undergoing desmotomy or desmectomy