Destructive Lesions of the Proximal Sesamoid Bones as a Complication of Dorsal Metatarsal Artery Catheterization in Three Horses

Objective— To describe focal destructive lesions of the proximal sesamoid bones (PSBs) as a complication of dorsal metatarsal artery catheterization performed for direct blood pressure monitoring during equine general anesthesia. Study Design— Retrospective study. Animals— Three client-owned horses. Methods— A dorsal metatarsal artery was catheterized in each of 3 horses for direct blood pressure monitoring during anesthesia. Radiography, ultrasonography, synoviocentesis, and arthroscopy were used to diagnose postoperative lameness that occurred in the limb used for blood pressure monitoring. Results— Horses developed severe lameness, localized to the fetlock region of the catheterized limb within 21 days of surgery. Antibiotic therapy was administered. Surgical debridement was possible in 1 horse. Two horses that had lesions that were inaccessible, failed to respond to medical management and were euthanatized. The 3rd horse that had surgical debridement of affected bone, survived. Changes in hospital protocol, by improving aseptic technique during catheter insertion and use of new manometer tubing and heparinized saline for each arterial catheter inserted in the dorsal metatarsal artery, have eliminated this complication. Conclusions— Diagnosis and treatment of destructive lesions of the PSB were difficult. Strict aseptic technique should be followed during insertion of arterial catheters. Clinical Relevance— Focal destructive lesions of the PSB subsequent to dorsal metatarsal arterial catheterization is a rare but serious complication of equine anesthesia.