Concurrent proximal suspensory desmopathy and injury of the proximal aspect of the accessory ligament of the deep digital flexor tendon in forelimbs or hindlimbs in 19 horses

Abstract

Clinical features of proximal suspensory desmopathy (PSD) and concurrent injury of the proximal aspect of the accessory ligament of the deep digital flexor tendon (ALDDFT) have not been documented. The objectives were to describe clinical signs and diagnosis. This was a retrospective study. Patient details, lame limb(s), response to diagnostic analgesia, and radiographic and ultrasonographic findings were recorded. PSD and injury of the proximal aspect of the ALDDFT were identified in 19 horses, 14 with forelimb lameness (unilateral 5, bilateral 9) and 5 with hindlimb lameness (unilateral 2, bilateral 3). Localising clinical signs were seen in 7/31 lame limbs (subtle thickening in the region of the ALDDFT [n = 3], pain on palpation of the body of the suspensory ligament (SL) [n = 6], heat in the proximal metacarpal or metatarsal region [n = 2]). Forelimb lameness was abolished by perineural analgesia of the palmar metacarpal (subcarpal) nerves in 17/23 limbs. In the remaining limbs intra-articular analgesia of the middle carpal joint (n = 2) or an ulnar nerve block (n = 4) were required to eliminate the lameness. Hindlimb lameness was abolished by perineural analgesia of the deep branch of the lateral plantar nerve (n = 2) or local infiltration of the proximal plantar aspect of the metatarsus (n = 3); a tibial nerve block resolved lameness in the remaining 3 limbs. Lesions of the SL and of the ALDDFT were characterised ultrasonographically by enlargement, heterogeneous echogenicity and loss of long linear echoes in longitudinal images. In 3 horses adhesions between the ALDDFT and the SL were identified post mortem. Close apposition of these structures seen ultrasonographically may indicate adhesion formation. It was concluded that the clinical features of PSD and concurrent injury of the ALDDFT are similar to those for PSD alone, highlighting the need for comprehensive and systematic ultrasonographic assessment.

Where does it hurt? Problems with interpretation of regional and intra‐synovial diagnostic analgesia

“…• Clinicians can become obsessed with the idea that horses have only one source of pain causing lameness, but in the current authors' experience, this is often not the case Murray 2003, 2012;Girodroux et al 2009;Zimmerman et al 2011;Dyson 2014a,b;Marneris and Dyson 2014;Barstow and Dyson 2015;Dyson and Rasotto 2015;Plowright and Dyson 2015). When employing diagnostic analgesia, one should always keep an open mind and assess the gait of the horse afresh on every single post analgesia trot, as subtle changes may occur.…”

“…; Zimmerman et al . ; Dyson ,b; Marneris and Dyson ; Barstow and Dyson ; Dyson and Rasotto ; Plowright and Dyson ). When employing diagnostic analgesia, one should always keep an open mind and assess the gait of the horse afresh on every single post analgesia trot, as subtle changes may occur.…”

“…), and lameness induced by collagenase injection into the lateral branch of the SL was not alleviated by an ulnar nerve block alone (Keg et al . ), perineural analgesia of the ulnar nerve is usually effective in resolution of pain associated with PSD or proximal lesions of the ALDDFT (Dyson ; Plowright and Dyson ). The reason for this is not clear.…”

“…The use of an ulnar nerve block can be helpful to differentiate proximal metacarpal region pain from carpal pain. Although there is histological evidence to suggest that both median and ulnar nerves contribute to the innervation of the SL (Muylle et al 1998), and lameness induced by collagenase injection into the lateral branch of the SL was not alleviated by an ulnar nerve block alone (Keg et al 1996), perineural analgesia of the ulnar nerve is usually effective in resolution of pain associated with PSD or proximal lesions of the ALDDFT (Dyson 2012a;Plowright and Dyson 2015). The reason for this is not clear.…”

Evaluation of poor performance in competition horses: A musculoskeletal perspective. Part 2: Further investigation

“…The results of nuclear scintigraphic evaluation of 141 sports horses were reported (Ehrlich et al 1998), but the results were not correlated with in depth clinical investigations. There have been a number of clinical reports which indicate that often several problems coexist contributing to pain and poor performance Murray 2003, 2012;Girodroux et al 2009;Zimmerman et al 2011a;Dyson 2014a,c;Marneris and Dyson 2014; Barstow and Dyson 2015;Plowright and Dyson 2015;Dyson and Rasotto 2016). These reports indicate the crucial role of diagnostic analgesia for determination of the source(s) of pain causing lameness and also highlight the importance of ridden exercise.…”