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.