Improved Biomechanical Performance of Tibial Spine Fracture Repair With Suture and Anchor Fixation in Pediatric Cadaveric Knees.

Abstract

Background: Prior studies in porcine and adult human bone suggest that suture fixation is superior to screw fixation of pediatric tibial spine fractures (TSFs). However, we have previously demonstrated that 2-suture repair was biomechanically comparable with 2-screw repair in human pediatric cadaveric knees.

Purpose: To evaluate whether TSF fixation with sutures attached to anchors placed in stronger metadiaphyseal bone would produce biomechanically superior repair to 2-screw and 2-suture constructs.

Study design: Controlled laboratory study.

Methods: Six pediatric cadaveric knees were acquired. We applied the same TSF creation protocol used in our previous study, then repaired the fractures by passing 2 No. 2 FiberWire sutures through the fracture fragment and the base of the anterior cruciate ligament, with sutures passed through bony tunnels and secured to two 2.8-mm anchors in the metadiaphyseal cortex. This construct of suture plus suture anchor (suture anchor group) underwent the same biomechanical loading protocol used in our prior study, in which pediatric knees were randomly assigned to either screw fixation (n = 6; fractures reduced with two 4.0-mm cannulated screws and washers) or suture fixation (n = 6; fractures repaired as in the suture anchor group except the sutures were tied across a metaphyseal bony bridge after their exit from the bony tunnels). All specimens were mounted in flexion and biomechanically tested with cyclic loading followed by a load-to-failure test. New data were statistically compared with the prior study's results.

Results: The suture anchor group had a median age of 9.00 years, while the screw and suture groups had identical median ages (8.50 years). All groups had an identical number of samples of each laterality. The ultimate failure load differed significantly across fixation methods (P = .006), primarily driven by higher ultimate failure loads in the suture anchor group (225.50 ± 46.46 N) when compared with the screw group (143.52 ± 41.97 N; P = .01) and suture group (135.35 ± 47.94 N; P = .009).

Conclusion: TSF fixation with sutures tied to metadiaphyseal suture anchors provided significantly stronger repair than 2-suture and 2-screw constructs.

Clinical relevance: The suture anchor fixation method for TSF may offer enhanced stability and durability to reduce the risk of postoperative complications while improving functional patient outcomes.