Optimization of the design of a barbed suture for flexor tendon repair using extended finite element analysis

Aim: Use of barbed sutures for flexor tendon repair is a promising technique. These sutures lie within the substance of the tendon, avoiding the need of external knots and so improving tendon gliding. The load is dispersed equally along the length of the barbed suture, decreasing the possibility of rupture. The purpose of this article is to propose enhanced suture geometry by comparing different cross-sectional configurations, barb cut angles and cut depths using the finite element method.Methods: Inspired by the geometry of flexor tendons, an elliptical cross-sectional wire was investigated. Mechanical behavior of five different aspect ratios (ρ = 1/3, 1/2, 1, 2, 3), three different cut angles (150°, 154°, 160°) and three cut depths (0.07-mm, 0.12-mm, 0.18-mm) were studied via extended finite element analysis using ABAQUS, for two different loading conditions: one to assess the strength of the suture and the second to evaluate the strength of a single barb. An extended finite element method has been implemented on ABAQUS to predict crack growth in viscoelastic material.Results: Based on these results, an elliptical suture having an aspect ratio of 1/2, 160° of cut angle, and 0.12-mm of cut depth is recommended.Conclusion: Barbed sutures are a good option for tendon repair. Our experiments assessed the mechanical performance of barbed sutures and suggested an optimized suture geometry for a single-stranded repair technique