Horses often sustain wounds to their lower extremities, where there is minimal soft tissue to protect the underlying bone structure. Frequently, these wounds are treated successfully and appear to heal well, however within the next several weeks a draining tract may develop at the site of the previously “healed” wound. In other cases, the wound may appear to be healing well and then progress may stall, resulting in a persistent, non-healing portion of the wound.
In cases like these it is not uncommon that the reason for the abnormal healing is a sequestrum. A sequestrum is a devitalized, and typically infected, piece of bone that acts like a foreign body (think “splinter”) to prevent complete healing of the wound. These sequestra form when the blood supply to the bone is damaged or disrupted due to the initial wound, however often take 3-6 weeks to be identified.
Sequestrum treatment takes many forms. Often an initial treatment approach is to try to treat the infection with topical and systemic antibiotics, however if this is not successful, the recommended definitive treatment is surgical removal of the sequestrum and debridement (removal) of the infected wound bed. Typically this is performed under general anesthesia to accomplish thorough debridement and cleansing, but may be possible in the standing, sedated horse in some instances.