An investigation into the occurrence of, and risk factors for, concurrent suspensory ligament injuries in horses with hindlimb proximal suspensory desmopathy

Abstract

Hindlimb proximal suspensory desmopathy (PSD) is a common cause of lameness or poor performance in horses and may occur alone or together with other suspensory ligament (SL) injuries in forelimbs or hindlimbs. The aims of this retrospective case-control study (January 2009 to December 2018) were to describe the occurrence of, and identify risk factors for, concurrent SL injuries in horses with hindlimb PSD. Data concerning age, breed, sex, work discipline, height, bodyweight and work history were collected. Concurrent SL injuries were defined as forelimb proximal suspensory desmitis or SL branch injuries (≥grade 2 [0-3]) in any limb. Hindlimb PSD was graded mild, moderate or severe based on ultrasonography. Data were described, and multivariable logistic regression modelling was used to identify factors associated with concurrent SL injuries. Data were available for 923 horses with hindlimb PSD, 28.6% (n = 264) of which had concurrent SL injuries. Age category (≤5 years of age vs. ≥6 years of age; P = 0.008), bodyweight: height ratio (P = 0.001), breed (P = 0.05), symmetry vs. asymmetry of hindlimb PSD ultrasonography grade (P = 0.005) and asymmetry vs. symmetry of lameness grade (P = 0.02) were associated with concurrent SL injury in horses with hindlimb PSD. Compared with horses aged ≥ 6 years, younger horses (odds ratio [OR] 1.76; 95% confidence interval [CI] 1.2-2.7) were more likely to have concurrent SL injury. The risk for concurrent SL injuries increased for every unit increase in bodyweight:height ratio (OR 2.27; CI 1.4-3.7). Compared with Thoroughbred crosses, Warmblood crosses (OR 3.3, CI 1.4-7.8), Thoroughbreds (OR 2.9, CI 1.1-7.1) and Irish Draught Horses (OR 3.5, CI 1.3-9.9) were more likely to have concurrent SL injuries. Hindlimb PSD ultrasonography grade severity was not associated with concurrent SL injury. In conclusion, age, bodyweight:height ratio and breed influenced the risk for concurrent lesions of the SL ligament. Further prospective studies in young horses are warranted.

Equine tendon mechanical behaviour: Prospects for repair and regeneration applications

“…Equine studies have shown a potential relationship between obesity, or body weight:height ratio, with the development of orthopaedic problems. A linear relationship between CSA of SDFT and BMI was also reported for 6-year-old horses (Agut et al, 2009;Gruyaert et al, 2020). Another study investigated several risk factors for SDF tendinopathy Odds ratio (OR) and showed an increased OR with increasing body weight (≥470 kg) and also reported that risks of SDF tendinopathy in males and geldings were significantly higher than in females (Ikeda et al, 2019).…”

Crooked tail carriage in horses: Increased prevalence in lame horses and those with thoracolumbar epaxial muscle tension or sacroiliac joint region pain

“…However, a predominance of left hindlimb lameness has previously been documented (Gruyaert et al . 2020). Horses are frequently led and mounted from the left, and it is possible that asymmetry in the rider’s hands and seat could introduce a level of asymmetry within the horse.…”

Letter to the Editor: Regarding recent paper by Pezzanite et al.

“…Whilst acknowledging that none of the techniques for local anaesthesia of the proximal metacarpal and metatarsal regions is specific, the authors (Pezzanite et al 2020) make an assumption that 60% improvement in lameness is sufficient. We would challenge this and suggest that with primary proximal suspensory injuries, we would expect to observe at least 90% improvement in lameness in forelimbs (Gruyaert et al 2020) and ≥80% improvement in lameness in hindlimbs (Dyson and Murray 2012), with residual lameness being abolished by ulnar or tibial nerve blocks in forelimbs and hindlimbs, respectively. The need to add ulnar or tibial nerve blocks would also prompt careful ultrasonographic assessment for the detection of possible adhesions between the suspensory ligament and adjacent osseous and soft tissue structures (Dyson et al 2017(Dyson et al , 2018, and assessment of the accessory ligament of the suspensory ligament (Dyson 2014), the accessory ligament of the deep digital flexor tendon (Dyson 2012;Plowright and Dyson 2015) and in hindlimbs, the lateral digital flexor tendon (Davis et al 2014).…”

“…We therefore advocate that radiographic and ultrasonographic evaluation of the carpus and proximal metacarpal region or tarsus and proximal metatarsal region should be performed routinely after apparently localising pain causing lameness to the proximal metacarpal or metatarsal regions (Dyson 2018b). We also recommend that if a proximal suspensory ligament lesion is identified, the suspensory ligament should be examined in its entirety, because concurrent suspensory ligament branch injuries may coexist, despite an absence of detectable improvement after palmar (plantar) and palmar metacarpal (plantar metatarsal) nerve blocks in the distal third of the metacarpal (metatarsal) region (the so-called 'low-4-point' block) (Marneris and Dyson 2014;Gruyaert et al 2020). We have also observed, as in the report by Pezzanite et al (2020), that some horses with pain originating in the condyles of the third metacarpal bone may have lameness which is not abolished by a 'low-4-point' block, but lameness resolves after perineural analgesia of the palmar metacarpal nerves just distal to the carpus (Dyson 2013b).…”

“…Frequently, a management plan can be advised if there is definitive ultrasonographic evidence of suspensory ligament injury and these reflect the clinical findings. In the United Kingdom, we have seen a substantial increase in the frequency of occurrence of hindlimb proximal suspensory desmopathy in sports horses in recent years (2009-2018) compared with 1998-2003 (Gruyaert et al 2020). Hindlimb proximal suspensory desmopathy was identified ultrasonographically in 923 of 2296 horses (40.2%) undergoing orthopaedic assessment.…”