Biomechanical and clinical evaluation of the epitenon-first technique of flexor tendon repair

Thirteen matched pairs of canine flexor tendons were repaired using both the Epitenon-first and the modified Kessler with an epitendinous running suture. These were then tested to failure with a longitudinal force in an Instron test machine. Human cadaver flexor digitorum profundus tendons were used to determine the cross sectional area of the tendon that is displaced by suture material of the Kessler repair and Epitenon-first core suture. Results of biomechanical testing revealed the epitenon-first technique to be 22% stronger than the modified Kessler technique. Comparison of tendon repair cross sectional contact areas by digital scanning of surface photomicrographs demonstrated 20% of the surface area of the repair is occupied by the knot of the modified Kessler technique, while the core suture of the epitenon-first repair consumed only 2.6% of the cross sectional area. These findings correlate with our clinical results of 26 zone II flexor tendon repairs in 18 patients repaired with the epitenon-first technique over a 4-year period. Of these, there has been one rupture and no repeat operations for lysis of adhesions.