A Krackow-based suture technique as a novel alternative for feline patellar fracture repair: a biomechanical comparison.

ObjectivesThe aim of the study was to evaluate the biomechanical properties of the combination of circumferential and Krackow sutures using FiberWire compared with the conventional methods in feline transverse patellar fractures.MethodsA total of 24 feline cadaveric pelvic limbs (mean body weight 3.74 kg) were harvested, and the patella of each limb was osteotomised transversely to simulate a fracture. The limbs were then randomly assigned to 1/3 stabilisation methods (n = 8 per group): group 1 (PFW) was stabilised with a modified tension band wire with a 0.9 mm Kirschner wire and No 2 FiberWire; group 2 (CFS) was stabilised with a circumferential and figure-of-eight suture with No 2 FiberWire; and group 3 (CKS) was stabilised with a circumferential and Krackow suture with No 2 FiberWire. All knee joints were fixed at a 135° neutral standing angle and tested by applying tensile force. Loads at 1, 2 and 3 mm gap formation, the maximum failure load and failure modes were recorded.ResultsAt 1 mm displacement, group 3 (mean tension 96.1 ± 18.6 N) was significantly stronger than group 1 (P <0.017). At 2 mm and 3 mm displacements, group 3 (mean tension 162.4 ± 12.2 N and 238.6 ± 25.4 N) was significantly stronger than both groups 1 and 2 (P <0.017). The maximum failure load of group 3 (mean tension 352.3 ± 31.0 N) was significantly higher than groups 1 and 2 (P <0.017). The primary failure mode was pin pull-out (group 1), suture pull-out (group 2) and tendon rupture (group 3).Conclusions and relevanceThe combination of circumferential and Krackow suture technique provides greater resistance to fragment displacement and construct failure than conventional methods in this ex vivo feline patella fracture model.