Primary flexor tendon repair: the mechanical limitations of the modified Kessler technique.

The aim of primary suture of flexor tendons in the hand is to achieve full function as soon as possible with a one stage operation. Much interest has been aroused by this subject and more recently by the possibility of improving results by postoperative active movement of the repaired tendon. We report the results of mechanical testing of the modified Kessler suture which suggests that the peripheral stitch is an important structural component of the suture. It is not merely a 'tucking in' stitch, but is essential to prevent very early gap formation. Steel is the best material for the central or core part of the suture. Cautious active postoperative movements may be possible using the modified Kessler suture, but within a narrow range of safety and with careful supervision.