Biomechanical assessment of suture techniques used for tendon repair.

Objective: The aim of this study was to assess different tendon suture techniques from the perspectives of both tensile strength and early active mobilization.
Methods: In this study, we implemented repairs on 40 flexor digitorum profundus (FDP) tendons, acquired from fresh frozen cadavers. The tendons were divided into 5 groups of 8 tendons each. We applied the 2-strand modified Kessler suture technique in the first group, the 4-strand Strickland suture technique in the second group, the 4-strand modified Kessler (without epitenon suture) suture technique in the third group, and the 4-strand modified Kessler (with epitenon sutures) suture technique in the fourth group. The remaining 8 intact tendons were set aside as the control group. The strength of the different tendon suture techniques were measured using the Instron(®) device.
Results: The average tolerance strength of the first group was determined as 39.89 ± 9.65 Newtons (N), the average tolerance strength of the second group was 39.64 ± 9.14 N, the average tolerance strength of the third group was 50.29 ± 11.24 N, the average tolerance strength of the fourth group was 54.47 ± 6.83 N, and the average tolerance strength of the control group was 119 ± 17.59 N. The tensile strength of the fourth group was significantly higher (p<0.05) than the first group, and the tensile strength of the third group was also significantly higher (p<0.05) than the first group. No significant difference was observed between the tensile strengths of the second and first groups (p>0.05).
Conclusion: According to our findings, the tensile strength of 4-strand sutures, with or without epitenon sutures, are significantly higher than the tensile strength of 2-strand sutures. All suture techniques applied had sufficient tensile strength to promote early mobilization.