Distal limb cast sores in horses: risk factors and early detection using thermography.
Authors: Levet T, Martens A, Devisscher L, Duchateau L, Bogaert L, Vlaminck L
Journal: Equine veterinary journal
Summary
# Editorial Summary: Distal Limb Cast Sores in Horses Cast-related pressure sores represent a significant welfare concern during distal limb immobilisation, yet until this Belgian study, clinicians lacked robust data on their prevalence, risk factors and early detection methods. Levet and colleagues prospectively monitored 70 horses undergoing distal limb casting over a mean period of 31 days, grading any sores as superficial, deep dermal or full-thickness ulcerations at removal, whilst simultaneously evaluating static thermographic imaging of the casts in 35 cases. The findings were sobering: 81% of casted limbs developed at least superficial sores, with 34% progressing to deeper involvement; older horses, those with normally-sized (non-swollen) limbs, and longer immobilisation periods showed significantly higher sore severity, whilst thermographic temperature differentials (ΔT) between the coolest cast surface and predisposed regions (dorsoproximal cannon bone and palmar/plantar fetlock) proved highly predictive of sore development (ΔT >23°C for superficial sores and >43°C for deep dermal lesions). Given the widespread use of distal limb casts in equine practice, these findings underscore the importance of rigorous padding protocols and cast monitoring protocols—particularly for geriatric patients and those with non-inflammatory injuries—with infrared thermography offering an objective, non-invasive means of detecting problematic pressure zones before significant tissue damage occurs.
Read the full abstract on PubMed
Practical Takeaways
- •Expect cast sores in most distal limb casts; plan cast changes and monitoring accordingly, especially in older horses and those requiring casts longer than 3-4 weeks
- •Use static thermography as an objective early detection tool during casting — temperature differentials >23°C warrant increased monitoring or cast adjustment to prevent deep tissue damage
- •Monitor normal (non-swollen) limbs more closely than swollen ones, as they show paradoxically higher sore risk, suggesting fit and pressure distribution are critical factors
Key Findings
- •81% of horses (57/70 legs) developed at least superficial cast sores, with 34% developing deep dermal sores and one full thickness ulceration
- •Cast sore severity increased with horse age (OR: 1.111), normal (non-swollen) limbs (OR: 3387), and longer casting duration (OR: 1.363 per week)
- •Thermographic temperature differential (ΔT) between coolest cast point and predisposed regions correlated with sore severity, with optimal cut-off values of ΔT = 23°C for superficial sores and ΔT = 43°C for deep dermal sores (OR: 2.100, P = 0.0005)