THE ROLE OF SUTURE MATERIALS IN DIGITAL FLEXOR TENDON REPAIRS

Abstract

Stronger flexor tendon repair techniques achieving excellent zero time biomechanics are considered the cornerstone of the early active motion rehabilitation protocols in digital flexor tendon surgery. Stronger suture materials are being introduced constantly without being tested biomechanically. The purpose of this study was to identify the role of the suture material on the flexor tendon repair techniques.

Seventy two tendon segments from thirty six cadaveric flexor tendons were lacerated and repaired with 2 different repair techniques and 3 different suture materials. The repair techniques involved an easier form of the popular Strickland technique and the stronger Modified Becker technique. Ethilon, Ethibond and the newer Fiberwire sutures were used, creating a wide range of materials with diverse biomechanical properties. The repair constructs were tested in an in vitro linear load to failure model where the ultimate strength, the 2 mm gap load and the mode of failure were recorded. Furthermore, a similar test was performed using only suture materials tied in a loop in order to compare the materials without any tendon or repair technique interaction.

The Modified Becker repairs demonstrated higher loads to failure than the Modified Strickland repairs irrespective of the suture material. Stronger suture materials increased significantly the strength of the modified Becker repair. The biomechanical characteristics of the modified Strickland technique were not influenced by the different suture materials. The 2 mm gap loads were not influenced by the suture material with either technique. The mode of failure was by suture breakage in the case of the Modified Becker repair and mostly by suture pullout in the case of the modified Strickland technique. The superior strength characteristics of the Fiberwire over the rest of the suture materials were also observed in the suture material study.

Suture materials do not have a significant effect on the biomechanical characteristics of every flexor tendon repair technique. Techniques most likely to benefit are those that grasp the tendon substance tightly and are limited only by the breaking strength of the suture material itself.