Veterinary advice should be sought before applying any treatment or vaccine.


Sesamoiditisis refers to proliferative or degenerative bony changes of the horse's proximal sesamoid bones, which are the paired teardrop shaped bones located behind the fetlock joint. There are two general forms of sesamoiditis which have been described in horses, a 'periostitis' form and an 'osteitis' form.
  • Periostitis form: This form of sesamoiditis occurs as a result of damage to the bone-ligament interface with the sesamoid bones. This can result from injuries to the palmar/plantar annular ligament of the fetlock, distal sesamoidean ligaments of the fetlock, or the suspensory ligament branches.
  • Osteitis form: Occurs as a secondary result of horses with arteriosclerosis, thrombosis, and local ischaemic necrosis.
The clinical signs observed in horses with sesamoiditis include moderate to severe lameness with swelling, heat and pain. In some cases the area of the injury may feel enlarged on palpation.

Treatment of horses with sesamoiditis depends on the underlying cause, associated with the form developed, severity, and whether horses are acutely or chronically affected. Recent studies suggest that horses with severe sesamoiditis are five times more likely to develop suspensory ligament branch injury (SLBI) in yearlings which are clinically normal at the time of the sale.


Lameness, usually only during heavy work
Mild, local swelling, heat and pain
Reduced range of motion in the fetlock joint


  • History
  • Clinical signs
  • Lameness exam - Distal limb flexion test may result in lameness
  • Radiography - Presence of enlarged or irregular vascular channels in the abaxial side of the proximal sesamoid bones
  • Ultrasound
  • MRI



Extended stall rest and external support
Analgestic, anti-inflammatory drugsIndicated for pain and inflammation
Extracorporeal shockwave therapy (ECSWT)Useful for chronic entheseopathy of the suspensory ligament, palmar annular ligament or distal sesamoidean ligaments.
Local Tildren injectionsUsed to suppress ongoing osteolysis or bone inflammation.
Platelet-rich plasma (PRP) therapy
Aquatread exercising
Isoxuprine hydrochlorideA type of peripheral vasodilating drug used for horses with the osteitis form.


  • Wrap legs with bandages that limit fetlock overextension during exercise
  • Regular trimming and shoeing
  • Watch workload intensity levels

Scientific Research

General Overviews

Age Range

It is often seen in young racehorses and jumping horses between 2 and 5 years of age.

Risk Factors

  • Poor conformation - horses with long, sloping pasterns are more at risk of developing sesamoiditis.

Horse Case Stories