Sesamoid Fractures in Horses: Fetlock Injury, Lameness, and Prognosis

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Quick Answer
  • See your vet immediately. A sesamoid fracture is a painful fetlock injury that can range from a small chip fracture to a catastrophic breakdown involving both sesamoid bones and supporting ligaments.
  • Most horses show sudden lameness, fetlock swelling, heat, pain on flexion, and reluctance to bear weight. Severe cases may have marked fetlock dropping or inability to stand normally on the limb.
  • Diagnosis usually starts with a lameness exam and fetlock radiographs. Ultrasound may be added to assess suspensory and soft tissue injury, which strongly affects prognosis.
  • Prognosis depends on fracture type, whether the joint surface is involved, forelimb versus hindlimb, and how much suspensory apparatus damage is present. Small fragments can sometimes return to athletic work after surgery and rehabilitation, while large basilar or catastrophic fractures carry a guarded to poor outlook.
  • Typical 2025-2026 U.S. veterinary cost range is about $800-$2,500 for initial exam and imaging, $3,500-$8,500 for surgical fragment removal or fixation in selected cases, and $8,000-$20,000+ for referral hospitalization, intensive care, or catastrophic injury management.
Estimated cost: $800–$20,000

What Is Sesamoid Fractures in Horses?

Sesamoid fractures in horses are breaks in the proximal sesamoid bones, the two small bones at the back of the fetlock joint. These bones help the suspensory apparatus support the fetlock during weight-bearing and fast exercise. When one fractures, the injury can affect not only bone, but also the joint surface, suspensory ligament branches, and nearby soft tissues.

This condition is especially important in athletic horses because the fetlock experiences very high forces during speed work, jumping, and hard turns. Some fractures are small apical or abaxial fragments that may be manageable with surgery and rest. Others are larger basilar, axial, or comminuted fractures that extend into the joint and can seriously destabilize the limb.

For pet parents, the key point is that this is not a wait-and-see problem. A horse with sudden fetlock pain or severe lameness needs prompt veterinary assessment so your vet can determine whether the injury is potentially repairable, whether the suspensory support is intact, and what level of care fits your horse's comfort, use, and prognosis.

Symptoms of Sesamoid Fractures in Horses

  • Sudden onset lameness
  • Fetlock swelling
  • Heat and pain around the fetlock
  • Pain worsened by fetlock flexion
  • Reluctance to bear weight
  • Dropped fetlock or abnormal limb angle
  • Reduced performance before a major injury

See your vet immediately if your horse develops sudden lameness, fetlock swelling, marked pain, or difficulty bearing weight. If the fetlock appears dropped, unstable, or the horse cannot stand comfortably, treat it as an emergency and limit movement until your vet arrives. Even fractures that look mild from the outside can involve the joint or important supporting ligaments, which changes treatment choices and prognosis.

What Causes Sesamoid Fractures in Horses?

Most sesamoid fractures happen when the fetlock is exposed to very high loading and overextension. This is why they are seen most often in performance horses, especially racehorses, where the fetlock repeatedly absorbs large forces at speed. Merck notes that proximal sesamoid fractures are relatively common and often extend into the fetlock joint, and many are associated with suspensory ligament damage.

The exact cause is not always one single bad step. In some horses, repeated high-speed exercise may create microscopic bone fatigue or remodeling changes that increase fracture risk over time. Research from Cornell has focused on these pre-fracture bone changes in racehorses, because catastrophic proximal sesamoid fractures can occur with little or no obvious warning.

Conformation, footing, workload, discipline, and shoeing may all contribute. Merck also notes that certain trailer-type shoes have been associated with hindlimb sesamoid fractures in Standardbreds. In practical terms, risk rises when a horse is asked to perform hard work on a limb that is already stressed, fatigued, or carrying subtle fetlock pathology.

How Is Sesamoid Fractures in Horses Diagnosed?

Your vet will usually begin with an urgent lameness and orthopedic exam, looking for swelling, heat, pain, fetlock instability, and how much weight your horse can place on the limb. In severe cases, the exam may be brief at first so the horse can be stabilized and moved as little as possible.

Radiographs (X-rays) are the main first test and are used to confirm the fracture, identify which sesamoid bone is involved, and see whether the fracture extends into the fetlock joint. Merck specifically notes that X-rays confirm the diagnosis. Multiple views are often needed because small apical or abaxial fragments can be missed on limited imaging.

Your vet may also recommend ultrasound to evaluate the suspensory branches and surrounding soft tissues, since ligament injury can make the prognosis much more guarded. In referral settings, advanced imaging such as CT, MRI, or nuclear scintigraphy may be used for complex cases, surgical planning, or when the fracture pattern is unclear. The final diagnosis is not only the bone break itself, but the full picture of bone, joint, and soft tissue damage.

Treatment Options for Sesamoid Fractures in Horses

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$800–$2,500
Best for: Small, non-displaced fractures; horses not intended to return to high-level athletic work; situations where referral surgery is not feasible; or cases where your vet believes comfort-focused management is the most appropriate option.
  • Urgent farm call or clinic exam
  • Pain control and anti-inflammatory treatment directed by your vet
  • Bandaging or external support when appropriate
  • Strict stall rest with controlled movement plan
  • Initial fetlock radiographs
  • Basic follow-up recheck imaging
Expected outcome: Variable. Some horses with small fragment fractures may become comfortable for pasture soundness or light use. Return to previous athletic performance is less predictable without surgery when fragments are intra-articular.
Consider: Lower upfront cost range, but there may be a higher risk of persistent lameness, joint arthritis, or reduced athletic outcome if a fragment remains in the joint. This approach is not appropriate for unstable or catastrophic injuries.
Most Common

Recommended Standard Treatment

$3,500–$8,500
Best for: Horses with repairable apical, abaxial, or selected non-comminuted fractures where surgery may improve comfort and athletic prognosis, especially when the horse is intended for future riding or performance.
  • Referral lameness and orthopedic evaluation
  • Full radiographic series of the fetlock
  • Ultrasound of suspensory branches and surrounding soft tissues
  • Surgical fragment removal or internal fixation in selected fracture types
  • Hospitalization, bandage care, and discharge plan
  • Structured rehabilitation with repeat imaging
Expected outcome: Often fair for small fragments treated promptly, and some horses can return to work or even racing. Prognosis becomes more guarded when the fracture is large, involves the joint surface extensively, affects the forelimb, or includes meaningful suspensory damage.
Consider: Higher cost range and a longer rehabilitation period, but this tier often gives the clearest diagnosis and the best chance of preserving joint function in suitable cases.

Advanced / Critical Care

$8,000–$20,000
Best for: Complex, unstable, comminuted, basilar, bilateral, or catastrophic sesamoid fractures; horses needing specialty surgical planning; or pet parents who want every reasonable diagnostic and treatment option explored.
  • Emergency referral hospitalization
  • Advanced imaging such as CT or MRI when indicated
  • Complex fracture fixation or salvage-oriented surgical planning
  • Intensive pain management and limb support
  • Management of severe suspensory apparatus injury or catastrophic breakdown
  • Extended hospitalization, repeated imaging, and specialty farriery/rehabilitation planning
Expected outcome: Guarded to poor in many advanced cases, especially when both sesamoid bones are fractured or blood flow to the foot is compromised. Some horses may be candidates for salvage or comfort-focused care, while others may have a grave prognosis despite intensive treatment.
Consider: This tier offers the most information and the widest range of interventions, but it carries the highest cost range and does not guarantee a return to function. In catastrophic injuries, advanced care may still lead to difficult welfare decisions.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Sesamoid Fractures in Horses

Bring these questions to your vet appointment to get the most out of your visit.

  1. Which sesamoid bone is fractured, and does the fracture extend into the fetlock joint?
  2. Is the fracture small and potentially repairable, or is it a larger basilar, axial, or comminuted injury?
  3. Do you suspect damage to the suspensory branches or other soft tissues around the fetlock?
  4. What are the realistic goals for my horse now: comfort, pasture soundness, light riding, or return to performance?
  5. Would referral surgery improve prognosis in this specific case, and how soon would it need to happen?
  6. What imaging do you recommend today, and what follow-up imaging will be needed during healing?
  7. What is the expected rehabilitation timeline, and what restrictions should I follow at home?
  8. What cost range should I plan for with conservative care, surgery, and possible complications?

How to Prevent Sesamoid Fractures in Horses

Not every sesamoid fracture can be prevented, especially in high-level athletes, but thoughtful management can help reduce risk. The goal is to limit repeated overload of the fetlock and catch smaller problems before they become major injuries. That means matching training intensity to fitness, building workload gradually, and taking subtle changes in performance or post-exercise fetlock filling seriously.

Regular soundness monitoring matters. If your horse develops intermittent lameness, shortened stride, repeated fetlock soreness, or declining performance, ask your vet whether a lameness workup is warranted before continuing hard work. Early imaging may identify fetlock or suspensory problems that need rest, treatment, or a training change.

Work with your vet and farrier on footing, shoeing, and limb support that fit your horse's discipline and conformation. Good conditioning, appropriate rest periods, and avoiding intense work on poor footing can all help. In racehorses and other high-demand athletes, prevention is often about many small management decisions rather than one single fix.

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