The intertarsal joint is a synovial roll-and-glide joint. Ligament damage and luxations of this joint are often the result of traumatic injury or growth deformities and result in significant functional impairment. A 9-month-old female Pekin duck (Anas platyrhynchos domesticus) was examined because of progressive, nonweight-bearing lameness of the left leg. Moderate effusive swelling was present at the level of the left intertarsal joint, without radiographic evidence of bone involvement. The duck failed to respond to nonsteroidal anti-inflammatory medications and analgesia and was diagnosed with rupture of the medial collateral ligament. Extracapsular surgical correction using bone tunnels and circumferential nylon suture on the medial aspect of the intertarsal joint led to a complete clinical resolution with normal return to function 2 weeks after surgery. This report reviews the anatomy and function of the intertarsal joint in the duck and details a simple extracapsular repair technique useful in the correction of collateral ligament rupture in this joint of ducks.