Tibial Anatomy and Functional Outcome in Growing Dogs with Tibial Tuberosity Avulsion Fracture Repair Followed by Implant Removal

The aims of this study were to compare tibial anatomy between a cohort of dogs that had implants removed following repair of tibial tuberosity avulsion fracture and a historical cohort that had implants left in situ, and to objectively quantify patient function to determine if deformity resulted in impaired function. Dogs that had open reduction and fixation of tibial tuberosity avulsion fracture with subsequent implant removal (Cohort A) had radiographs of both hindlimbs and objective gait analysis. Tibial plateau angle, patellar position, axial and transverse tibial tuberosity position, and total pressure index were compared between operated and normal limbs. Measurements of tibial anatomy of the operated limbs were then compared with a historical cohort of dogs that did not have implants removed (Cohort B). Five dogs in Cohort A had implants removed 23 to 28 days after tibial tuberosity avulsion fracture repair with no refractures. Operated limbs had a lower tibial plateau angle, greater axial tibial tuberosity position and smaller transverse tibial tuberosity position when compared with normal limbs, but there was no significant difference in total pressure index between operated and normal limbs. There were no clearly meaningful differences in tibial anatomy between Cohort A and B. However, Cohort A had no dogs with a tibial plateau angle less than 0 degrees, while 2/6 dogs in Cohort B had a negative tibial plateau angle. Implant removal 23 to 28 days after tibial tuberosity avulsion fracture repair did not preserve normal tibial anatomy; however, objective function was maintained.