Suspected multipartite patella in a Pomeranian dog successfully treated with osteochondral debridement, cerclage suture and transarticular external skeletal fixation

Abstract A 4‐year‐old, male, neutered Pomeranian presented with a 3‐week history of an acute‐onset Grade 3/5 left pelvic limb lameness, with no reported history of trauma. Radiographic and computed tomographic studies revealed separation of the left patella into multiple small variably sized, minimally displaced, bony fragments, with rounded margins. A chronic multipartite malformation or, less likely, a delayed comminuted fracture were both considered possible differentials. After 4 months of unresponsive conservative management, surgical treatment was implemented. The articular surface of the patella was debrided with removal of three small osteochondral fragments. A cerclage suture was placed around the patella, and a transarticular external skeletal fixator was applied, removed 6 weeks postoperatively. The patient recovered successfully with complete resolution of clinical signs 7 weeks post removal of the transarticular external skeletal fixator. This complex clinical manifestation and successful treatment approach has not previously been described in a small breed dog.