Use of cannulated screws in the treatment of unicondylar humeral condylar fractures in dogs

Objective To describe unicondylar humeral fracture (UHF) repair using cannulated transcondylar screws, report postoperative fracture reduction, healing, and complication rates. Study design Retrospective. Animals A total of 49 client owned dogs with UHF. Methods Surgical technique and approach (i.e., open, limited open, or minimally invasive) were recorded. Articular step defect (ASD) and gap (Gap) at the humeral condylar articular surface were measured on pre- and postoperative images and reported as percentages. Fracture healing was graded on follow-up radiographs. Functional outcome was based on client questionnaire over the phone. General linear models were used to assess the impact of surgical approach on %ASD, %Gap, whereas Cox regression was used to assess prognostic factors of full fracture healing. Results A total of 49 fractures repaired with a transcondylar screw with or without an antirotational pin(s) were included. Surgical approach did not have an impact on postoperative %ASD, %Gap or development of complications. The overall complication rate was 26% (11/42), with no revision surgery necessary. Of the dogs that encountered complications, 50% required pin and/or screw removal after fracture healing. For 29 dogs with a minimum of four-month owner telephone questionnaire follow-up, 90% reported no lameness and only three reported intermittent lameness. Achieving complete fracture healing was affected by increased postoperative %ASD (p = .033). Conclusion The UHFs repaired by transcondylar cannulated screws had acceptable outcomes and fracture reduction with complication rates being similar regardless of the surgical approach. Clinical significance Cannulated screws can be implanted with varying surgical approaches to successfully repair UHFs with comparable clinical outcome to previous reports.