Abstract
OBJECTIVE: In chronic hand flexor tendon reconstruction with tendon grafts, the challenge is to obtain the best resistance and tension of the suture that allows early active mobility. This experimental study of tension relaxation aims to investigate whether prior preconditioning of the tendon graft could assist to identify the ideal tendon graft tension in these reconstructions. METHODS: The porcine flexor tendons were subjected to the tension relaxation test, with three test cycles each with up to 50 N of tension and relaxation for 300 seconds. Measured: maximum force (N), maximum tension (Mpa) and maximum deformation. RESULTS: After the peak tension of 50 N, the following was observed: maximum deformation, with an average tendon elongation of 2.3 mm; average residual tendon elongation of 0.6 mm; demonstrating the viscoelastic spring characteristic of porcine tendons. CONCLUSION: We recommend performing intraoperative preconditioning of the tendon graft with loads close to active grip strength (50 N to 70 N). If it is impossible to perform preconditioning, the suture can be placed 17 degrees of flexion of the proximal interphalangeal joint above the cascade flexion of fingers, compensating for tendon elongation under a load of 50 N. Level of Evidence III; Experimental .