Pedal osteitis—inflammation of the distal (third) phalanx—is a potential cause of lameness originating from the equine hoof. It is diagnosed by radiographic evaluation, which reveals several features, including loss of mineral at the solar margin or enlarged vascular channels. However, these changes do not always resolve with time, making it difficult to know whether the radiographic changes represent an active source of lameness.
Pedal osteitis is thought to be the result of excessive concussive forces, especially in horses that have thin soles. The condition can affect the entire distal phalanx, or it can be confined to one or both palmar/plantar processes. Horses are commonly sore to hoof testers across the sole, or across the affected palmar/plantar process.
Horses with pedal osteitis typically improve after perineural anesthesia of the palmar/plantar digital nerves at the level of the proximal sesamoid bones (abaxial sesamoid block). Because radiographic changes do not always indicate an active process, advanced diagnostic imaging can be useful.
On nuclear scintigraphy, horses with pedal osteitis can show increased radiopharmaceutical uptake.
On MRI, the distal phalanx can be characterized by edema or sclerosis, depending on the stage of disease.
Treatment of pedal osteitis depends on the extent of lameness and the horse’s hoof conformation. Imposing a regimen of rest, administering systemic NSAIDs, and making shoeing changes are potential treatment options.
See Regional Anesthesia in Horses for discussion of specific anesthetic techniques used to localize lameness.
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Also see pet health content regarding pedal osteitis in horses.
