Comparison of two different suture-passing techniques with different suture materials and thicknesses: Biomechanical study of flexor tendons for yield points, gap formation and early post-operative status

Objective: The purpose of this study was to evaluate the biomechanical characteristics of two different suture-passing techniques with different suture materials and thicknesses and assess whether they could with stand passive and/or active mobilization in the very early post-operative period. Materials and Method: 192 flexor digitorum profundus communis tendons of similar diameters were obtained from sheep front limbs. Each tendon was transected completely at a point 6 cm from the distal end and each repaired by one of the following suture materials: polyester suture (Ethilon 3.0 and 4.0 (Ethicon, U.S.)) and polypropylene monofilament (Polypropylene 3.0 and 4.0 (Ethicon, U.S.)). The repair of the tendons was performed through employing two different techniques with each suture material the Bunnel and Modified Kessler. The primary outcome measures for each repair combination was suture material, suture-passing type and suture thickness. Regarding post-operative early motion, the yield point differences between the suture materials and techniques were compared. Results: There was a statistically significant difference between suture materials used for the repair. Tendons repaired with Ethibond needed significantly greater amounts of force for rupture compared with tendons repaired with Polypropylene. There was a statistically significant difference between Ethibond and Prolene for all study groups. Conclusion: The yield points with higher forces is expected to be preferred, but their thicknesses can be 3-0 or 4-0. Oblique suture passing should be preferred rather than longitudinal passing. Obviously, suture strengthening methods, like epitendineous running sutures and core sutures, should be used. Without these measures, even passive wrist motion can result in gap formation at the repair site. The results of this study showed that tensile properties of the repaired vary considerably with differences in suture material and design.