Locking Compression Plate Fixation of Equine Tarsal Subluxations

To report the clinical findings and outcome of locking compression plate (LCP) fixation of tarsal subluxations in horses.

Retrospective case series.

Horses (n = 3) and ponies (2).

All horses and ponies diagnosed with tarsal subluxations and treated with LCP fixation at our institution between 2011 and 2013 were included. Data were collected from the medical records, including all radiographic and computed tomographic (CT) studies and reviewed. Long-term (>1 year) followup examination, including owner interview, and clinical and radiographic examinations were performed for all cases.

Subluxations of the tarsometatarsal (n = 3) and proximal intertarsal (2) joints were diagnosed. CT examinations revealed complex joint injuries, including a combination of avulsion fragments and compression injuries at the opposite side of the joint from the subluxation. The LCP was applied to the plantarolateral or medial side of the limb. All horses survived and were discharged from the hospital. Short-term complications included mild laminitis (n = 1) and peroneus tertius rupture (2). At long-term followup, both ponies were sound and used as intended, whereas all horses showed mild to moderate lameness at the trot and were used for pleasure riding only. Radiographic signs of osteoarthritis developed in the joint affected by subluxation in all cases and in adjacent small tarsal joints in 2 horses and 1 pony.

LCP fixation of tarsal subluxations resulted in stable fixation and allowed adequate healing. Subluxation of the small tarsal joints represents a complex injury and osteoarthritis commonly develops in the affected and adjacent joints.