Suspensory Ligament Injury: What the Research Says
Evidence from 19 peer-reviewed studies
What Professionals Should Know
- •Both surgical approaches (desmoplasty with fasciotomy and neurectomy with fasciotomy) produce comparable outcomes for proximal suspensory desmopathy; surgeon experience and horse presentation should guide technique selection
- •Fetlock laxity is a potential post-operative complication (2.1% incidence) that should be discussed with owners; clinical monitoring is warranted in early recovery
- •Presence of suspensory ligament tearing on imaging may influence surgical approach selection, though both methods yield similar functional outcomes
- •Fracture risk increases significantly during the racing season (October through July), suggesting targeted injury prevention strategies should intensify during these months
- •SDFT and fracture injury rates have substantially increased since 2017 at HKJC, warranting investigation of changes in training protocols, track conditions, or horse populations during this period
- •Time-series monitoring of injury trends enables identification of high-risk periods to focus future risk factor studies and inform evidence-based management decisions
- •Horses with fetlock hyperextension or suspensory ligament injuries should avoid or have restricted use of medium and extended trot work; collected trot is biomechanically safer for these horses.
- •Extended trot creates significantly more forelimb loading stress than medium trot—monitor horses showing signs of forelimb injury more closely when performing extended paces.
- •The entire forelimb (carpus, shoulder, fetlock) experiences increased loading during lengthened trot, not just the fetlock—address forelimb conditioning holistically rather than focusing on single joints.
- •Monitor racehorses for tendon injuries during both training and racing phases, as training-related injuries are clinically common but often underreported in epidemiological data
- •SDFT and suspensory ligament injuries represent significant causes of wastage in racing Thoroughbreds and warrant preventive management strategies
- •Understanding the complete injury prevalence (training + racing) provides better risk assessment for racing operations and training programs
- •Poor blood supply is not the reason why horses commonly injure their hind suspensory ligaments—practitioners should look to biomechanical or functional factors instead
- •The uniform vascular distribution suggests that hind suspensory ligament injuries result from mechanical stress or overload rather than ischaemic vulnerability
- •Treatment protocols should focus on load management and rehabilitation rather than assuming compromised healing potential due to vascular insufficiency
- •Low-frequency therapeutic ultrasound may offer a quick, sedation-free treatment option for suspensory ligament injuries with an 87% success rate in returning sport horses to competition
- •Most horses respond within 3-4 weeks of treatment, allowing relatively rapid rehabilitation timelines for sport horses
- •This technique is practical for field or clinic use and doesn't require specialized horse handling or restraint
- •Microvesicles from specially treated stem cells may offer a simpler alternative to stem cell therapy for suspensory ligament injuries, potentially without the regulatory and safety challenges of live cell therapy
- •This single case suggests direct injection of microvesicles improved tissue healing markers (lesion filling, angiogenesis, elasticity) in a jumping horse with SL injury
- •Further clinical trials needed before recommending this treatment—currently only one horse treated, so clinical outcomes and return-to-work data are limited
- •Allogeneic tenogenically-induced MSCs combined with PRP may offer a viable option for chronic suspensory ligament injuries that fail to respond to conservative management over several months
- •Repeated injections (2 doses spaced 12 weeks apart) and extended rehabilitation timeline (32 weeks to return to sport) should be expected when using this regenerative approach
- •Ultrasound monitoring shows promise for tracking tissue healing and guiding re-injection timing in recalcitrant suspensory ligament cases
- •Extended trot training may be a risk factor for suspensory ligament injury in dressage horses; consider balancing extravagant movement work with appropriate rest and conditioning
- •Horses performing collected trot may experience different biomechanical loading patterns than extended trot, which could inform training programme design and injury prevention strategies
- •Young horses undertaking repetitive extended trot work for extravagant movement may warrant closer monitoring for early signs of suspensory desmitis
- •Microvesicles from treated stem cells may offer a novel regenerative therapy option for suspensory ligament injuries when traditional rehabilitation fails to restore function
- •This case suggests microvesicle-based treatments could address the ongoing challenge of returning SL-injured athlete horses to previous performance levels
- •Further clinical trials needed before widespread adoption, but the approach shows promise for improving tissue healing and elasticity in ligament injuries
- •Understanding the specialized structural differences between SDFT, DDFT, and suspensory ligament is critical for selecting appropriate diagnostic imaging and treatment protocols
- •The fibrocartilage component of the DDFT's intrasynovial portion has specific functional requirements that standard tendon healing may not address—consider tissue-specific rehabilitation strategies
- •Current knowledge gaps regarding enthesis structure mean newer therapies targeting the bone-ligament interface should be approached carefully and monitored closely for efficacy
- •Suspensory ligament injuries warrant greater clinical attention and investigation given their high prevalence across all horse types and disciplines; current diagnostic and treatment protocols need refinement based on improved understanding of structure-function relationships.
- •Practitioners should recognize that evidence gaps exist in SL management compared to other tendinous structures, suggesting current treatment approaches may not be optimized and should evolve as research clarifies underlying pathophysiology.
- •Future research priorities should focus on elucidating fundamental SL biomechanics and composition to improve injury prevention, diagnosis accuracy, and therapeutic outcomes.
- •Suspensory ligament injuries are common in performance horses; maintain high clinical suspicion when assessing lameness cases
- •Imaging (ultrasound) must accompany clinical examination for accurate diagnosis and to guide rehabilitation planning
- •Implement structured, progressive exercise protocols with regular ultrasound checks during recovery to optimize return to work and minimize re-injury risk
- •When performing tendon plating in horses, use figure-8 or hybrid suture patterns rather than simple interrupted patterns to significantly reduce risk of gap formation during healing
- •Figure-8 and hybrid patterns provide equivalent biomechanical strength, so pattern choice can be based on surgeon preference and ease of application
- •These findings support improved surgical technique selection for tendon injuries requiring plate fixation in foals and horses
- •Platelet-rich gel supernatant appears to modulate the inflammatory response in soft tissue injuries by reducing pro-inflammatory IL-1β while increasing anti-inflammatory mediators, which may support healing in suspensory ligament and tendon lesions
- •Suspensory ligaments and tendons respond differently to platelet-derived products, with ligaments showing greater anti-inflammatory responses; consider tissue type when selecting regenerative therapy protocols
- •The 50% concentration of Lr-PRGS showed more favorable anti-inflammatory profiles than higher concentrations, suggesting optimal dosing matters for clinical application
- •Neurectomy of the DBLPaN may resolve chronic thoracic limb lameness from PSD when conservative treatment fails, but carries risk of structural ligament weakening that could predispose to re-injury
- •Post-neurectomy denervation causes fat infiltration and atrophy of suspensory ligament muscle fibers, potentially compromising long-term biomechanical integrity
- •Carefully evaluate long-term soundness and exercise tolerance in horses undergoing this procedure, as the denervated ligament may be more prone to future injury
- •Suspensory ligament injuries result in measurable changes to collagen composition that reduce tissue quality and mechanical properties, supporting the need for targeted regenerative treatment strategies beyond rest alone
- •The shift toward higher proportions of type III and V collagen (immature/disorganized collagen) in injured tissue suggests that healing produces mechanically weaker fibrils, emphasizing importance of controlled rehabilitation protocols
- •These ultrastructural and biochemical changes provide objective markers for evaluating ligament injury severity and monitoring tissue regeneration during recovery
- •Suspensory ligament damage, particularly involving the medial branch, should be considered a risk factor for lateral condylar fracture in racehorses; early detection and management of ligament lesions may help prevent fracture
- •Horses with MBSL injuries require modified training and load management to reduce peak forces through the metacarpophalangeal region until ligament healing is complete
- •Diagnostic imaging for condylar stress or microfractures should be considered in racehorses presenting with concurrent suspensory ligament injury to identify fracture risk before catastrophic failure occurs
- •Simple gamgee and neoprene boots are ineffective for supporting MCP extension; avoid relying on these alone for tendon/ligament protection
- •3-layered bandages with contoured palmar splints provide meaningful support and are low-cost options for injury management
- •The Dalmar carbon fibre boot offers practical support during exercise with adjustable settings and is suitable for rehabilitation protocols
Key Research Findings
Both desmoplasty with fasciotomy (DF) and neurectomy with fasciotomy (NF) achieved similar rates of soundness and return to work in 141 horses with proximal suspensory desmopathy
Desmoplasty with fasciotomy was preferentially used in horses with evidence of suspensory ligament tearing, suggesting surgeon preference based on tear presentation
Three horses (2.1%) developed fetlock laxity (dropped fetlocks) post-operatively, the only significant complication observed
Neither surgical technique was associated with serious operative complications
1,471 injuries recorded over 8 seasons comprised 605 fractures (41.1%), 550 SDFT injuries (37.4%), and 316 suspensory ligament injuries (21.5%)
Fracture incidence demonstrated seasonality, increasing from October (0.25 per 1000 horses) to May (0.71 per 1000 horses), coinciding with racing season
Greatest SDFT injury incidence risk of 14.8 per 1000 horses and fracture risk of 1.3 per 1000 horses occurred since 2017
Time-series analysis identified peaks and cyclical patterns in MSI incidence that can inform targeted epidemiological investigations
Fetlock extension angle increased significantly in medium trot (5.70° increase, P<0.01) and extended trot (8.59° increase, P<0.01) compared to collected trot.
Fetlock extension was positively correlated with carpus extension (coefficient 0.61, P<0.01) and shoulder flexion (coefficient 0.18, P<0.05), indicating whole forelimb loading changes.
Extended trot produced greater fetlock hyperextension than medium trot, suggesting different injury risk profiles between lengthened paces.
Lengthened trot paces may be contraindicated in horses with existing fetlock hyperextension or suspensory ligament injury.
Study determined prevalence of SDFT and suspensory ligament injuries in Japanese Thoroughbred racehorses during 1999
Overstrain injuries to SDFT and suspensory ligament are among the most common musculoskeletal injuries in racing Thoroughbreds
Injuries sustained during training were included alongside racing injuries to establish overall prevalence
Evidence Base
Comparison of Two Surgical Techniques for the Treatment of Equine Hindlimb Proximal Suspensory Desmopathy
Kendra D. Freeman, M. N. Adams, Allison E. Salinger et al. (2025) — Animals : an Open Access Journal from MDPI
Using time-series analysis techniques to enhance the understanding of musculoskeletal injury in Thoroughbred racehorses.
Johnston Anna S, Riggs Christopher M, Cogger Naomi et al. (2020) — Equine veterinary journal
What Effect Does Medium and Extended Trot Have on the Kinematics of the Forelimb in Dressage Horses?
Walker V.A., Tranquille C.A., Dyson S.J. et al. (2015) — Equine Veterinary Journal
Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999.
Kasashima Y, Takahashi T, Smith R K W et al. (2004) — Equine veterinary journal
Microvasculature of the suspensory ligament of the equine hind limb
Williams Megan R., Crisman Evan, Taylor Brianne M. (2024) — American Journal of Veterinary Research
Assessment of Noninvasive Low-Frequency Ultrasound as a Means of Treating Injuries to Suspensory Ligaments in Horses: A Research Paper.
Carrozzo Ugo, Toniato Matteo, Harrison Adrian (2019) — Journal of equine veterinary science
Microvesicles isolated from 5-azacytidine-and-resveratrol-treated mesenchymal stem cells for the treatment of suspensory ligament injury in horse—a case report
Kornicka-Garbowska Katarzyna, Pędziwiatr Rafał, Woźniak Paulina et al. (2019) — Stem Cell Research & Therapy
Tenogenically Induced Allogeneic Mesenchymal Stem Cells for the Treatment of Proximal Suspensory Ligament Desmitis in a Horse.
Vandenberghe Aurélie, Broeckx Sarah Y, Beerts Charlotte et al. (2015) — Frontiers in veterinary science
The effect of collection and extension on tarsal flexion and fetlock extension at trot.
Walker V A, Walters J M, Griffith L et al. (2013) — Equine veterinary journal
Tissue Doppler Imaging in the horse
Gehlen H, Iversen C, Stadler P (2009) — Pferdeheilkunde Equine Medicine
Tendon/Ligaments: Structure and Composition.
S. Durgam (2025) — The Veterinary clinics of North America. Equine practice
A review of the equine suspensory ligament: Injury prone yet understudied.
Guest Deborah J, Birch Helen L, Thorpe Chavaunne T (2025) — Equine veterinary journal
Suspensory Ligament Injuries: Pathogenesis, diagnosis, treatment and rehabilitation
P. Zielińska, J. Nicpoń, K. Śniegucka (2022) — Medycyna Weterynaryjna
Ex vivo mechanical testing of various suture patterns for use in tendon plating.
Hale Michael J, Zellner Eric M, Naiman Jaron H et al. (2021) — Veterinary surgery : VS
Equine suspensory ligament and tendon explants cultured with platelet-rich gel supernatants release different anti-inflammatory and anabolic mediators
Bonilla-Gutiérrez Andrés F., Castillo-Franz Cristian, López Catalina et al. (2018) — Biomedicine & Pharmacotherapy
Histological changes in the proximal suspensory ligament after neurectomy of the deep branch of the lateral palmar nerve of horses with induced proximal suspensory desmitis.
Lopez-Navarro Gabriela, Trigo-Tavera Francisco J, Rodriguez-Monterde Alejandro et al. (2017) — Veterinary journal (London, England : 1997)
Characterization of collagen fibrils after equine suspensory ligament injury: an ultrastructural and biochemical approach.
Shikh Alsook M K, Gabriel A, Salouci M et al. (2015) — Veterinary journal (London, England : 1997)
Biomechanical investigation of the association between suspensory ligament injury and lateral condylar fracture in thoroughbred racehorses.
Le Jeune Sarah S, Macdonald Melinda H, Stover Susan M et al. (2003) — Veterinary surgery : VS
In vitro evaluation of nonrigid support systems for the equine metacarpophalangeal joint.
Smith R K W, McGuigan M P, Hyde J T et al. (2002) — Equine veterinary journal