Do adipofascial flaps affect the mechanical properties of a repaired tendon? A biomechanical rat model study

The aim of this study was to evaluate the effect of vascularized and non-vascularized fascial flaps on tendon healing, specifically the maximum strain, maximum stress, elasticity and resistance of the repaired tendon. Rats were randomly divided into 3 groups: Group 1 - primary repair; Group 2 - vascularized pedicled fascial graft; Group 3 - non-vascularized free fascial graft. The rats were euthanized after 2 weeks and 40mm-long samples were taken from the Achilles tendon and gastrocnemius muscle. To evaluate the mechanical properties of the tendons, maximum load, maximum deformation, energy stored until yield point and stiffness on the load-deformation curve were measured. Based on this mechanical testing, the best group in terms of tissue strength and quality was the primary repair group. When the samples were examined individually, the two samples with the highest breaking force after the control group were in the pedicled graft group. The worst results overall were in the free graft group. We believe that if the blood flow is preserved for the fascial flap in the pedicled graft group, the tendon's breaking force would be higher.