Long-term outcome of a canine longitudinal patellar fracture treated with lag screw and pin

Abstract

We report a rare case of a 4-year-old, female, mixed-breed dog with a longitudinal patellar fracture of the left hindlimb. Orthopaedic examination revealed pain, swelling and crepitus in the patella. Stifle radiography and computed tomography confirmed a longitudinal patellar fracture with lateral displacement of the fragment. A lateral parapatellar approach was chosen to assess the stifle joint. Intraoperative findings were consistent with the diagnostic imaging findings, with an additional partial tear of the quadriceps tendon at the fracture location. The fracture was treated using a 2 mm lag screw combined with a 1.25 mm K-wire, and the partial quadriceps tendon tear was repaired with a locking-loop suture. Despite a soft tissue injury due to temporary external coaptation treated conservatively, recovery was uneventful, and lameness gradually decreased, remaining lameness-free from postoperative Week 7. The dog finally returned to full activity without recurrence of lameness during long-term follow-up (422 days).