Single cortical positional screw for fixation of fibular head instability.

Fibular head instability is a rare, isolated injury in veterinary medicine, with no previous case reports in the veterinary literature. The fibular head is secured proximo-distally by the lateral collateral ligament and craniocaudally by the cranial and caudal fibular head ligaments. A 1-year-old, 26-kg, spayed female border collie mix dog was referred for chronic bilateral Salter Harris-II tibial tuberosity avulsion fractures. The dog was non-weight-bearing on the right pelvic limb, with pain and mobility localized to the right fibular head. Preoperative radiographs showed no fibular pathology. Intraoperatively, the cranial and caudal fibular head ligaments were completely torn, whereas the lateral collateral ligament remained intact. Open reduction and stabilization with a cortical positional screw was conducted. At the 8-week follow-up, the dog was sound at a walk, with a mild intermittent "hitch" at a trot. At 7 mo following surgery, the owner reported a return to high-energy activity. Key clinical message: This report documents the successful surgical repair of fibular head instability using a single cortical positional screw.