Concurrent Proximal Suspensory Desmopathy And Injury of the Proximal Aspect of the Accessory Ligament of the Deep Digital Flexor Tendon in Forelimbs and Hindlimbs
Authors: Plowright E., Dyson S.
Journal: Equine Veterinary Journal
Summary
# Editorial Summary Proximal suspensory desmopathy (PSD) and injuries to the accessory ligament of the deep digital flexor tendon (ALDDFT) are recognised separately in equine practice, yet Plowright and Dyson's 2014 retrospective case series documents a previously unreported concurrent presentation of these conditions affecting 13 horses (8 forelimb cases and 5 hindlimb cases). Using ultrasonographic examination and response to local analgesia blocks, the authors identified characteristic imaging features including enlargement and decreased echogenicity of both the ALDDFT and proximal suspensory ligament, with echogenic material present between these structures in five limbs. Clinical presentations varied: some horses showed bilateral lameness with concurrent injuries in both structures, whilst others exhibited recurrent lameness after prior treatment for isolated PSD, suggesting the ALDDFT pathology may be a secondary or overlooked component. Palmar metacarpal and plantar metatarsal nerve blocks abolished lameness in the majority of cases, confirming proximal metacarpal/metatarsal localisation, though some limbs required more proximal blocks (ulnar or tibial), indicating variable pain patterns. For practitioners, this work emphasises the importance of thorough ultrasonographic evaluation of all proximal metacarpal/metatarsal soft tissues when lameness localises to the palmar or plantar aspect of this region, as isolated assessment of the suspensory ligament risks missing concurrent ALDDFT pathology that may influence prognosis and rehabilitation protocols.
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Practical Takeaways
- •When lameness localizes to the proximal metacarpus/metatarsus region, ultrasound the entire proximal soft tissue area—don't assume single structure pathology; concurrent PSD and ALDDFT injuries are possible and may be bilateral
- •Response to palmar metacarpal or proximoplantar nerve blocks confirms pain localization to this region and should prompt comprehensive ultrasonographic evaluation of all structures
- •Recurrent lameness in horses treated for PSD may indicate missed concurrent ALDDFT pathology; thorough imaging at initial presentation is critical to avoid incomplete treatment
Key Findings
- •8 horses presented with concurrent PSD and ALDDFT injury in forelimbs (4 unilateral, 4 bilateral cases); 5 horses had hindlimb involvement with concurrent or historical bilateral PSD and ALDDFT desmopathy
- •Lameness was abolished by palmar metacarpal nerve blocks in 10/12 forelimbs and proximoplantar infiltration in 3/4 hindlimbs, indicating localized pain source in proximal metacarpus/metatarsus
- •Ultrasonographic findings in all affected limbs showed enlargement of ALDDFT and proximal SL with diffuse decrease in echogenicity, and echogenic material between SL and ALDDFT in 5/13 limbs
- •Recurrent lameness occurred in horses with unilateral (n=3) or bilateral (n=1) concurrent PSD and ALDDFT desmopathy despite previous treatment