Introduction: Bunnell suture technique is effective for tendon repair. A modification of the classic suture technique could increase ultimate failure point (UFP) on the suture-tendon site. The purpose of this study is to evaluate UFP of regular and modified Bunnell suture techniques on in vitro porcine patellar tendons.

Methods: Porcine patellar tendon samples (N=24) were used for this study, separating them in 2 groups: Group A: classic Bunnell suture on the tendon (N=12). Group B: two perpendicular Bunnell sutures at 90° between them on the tendon (N=12). After suturing the samples, axial traction until failure on the tendon-suture site was applied on samples of both groups documenting UFP with a tension sensor device. UFP was measured and described in Newtons for all samples. Statistics: Non parametric Mann-Whitney test for independent variables was used to analyze outcomes.

Results: The UFP for group A was 224 ± 38,9 N. The UFP for group B was 307 ± 19,9 N. We found statistical differences among groups (p=0,00006).

Discussion: In this study we analyzed the UFP of classic Bunnell suture technique vs. a modification adding a second Bunnell suture perpendicular to the classic technique. The purpose of this modification is to increase the contact area between the suture and the tendon, reaching a stronger disposition at suture-tendon site. This has been documented in the UFP values obtained.

Conclusion: Adding a perpendicular Bunnell suture run in porcine ex vivo patellar tendons increases UFP in tendon repair at tendon – suture site.