Cyclical testing of zone II flexor tendon repairs

Kessler, Strickland, or modified Becker repairs, all augmented with a runni ng circumferential epitenon suture, were performed for simulated zone II fl exor tendon lacerations in the index, long, and ring fingers of 12 fresh-fr ozen cadaveric specimens. Each hand was tested with a tensiometer built for curvilinear testing of human flexor tendons in an intact hand. Each tendon was cycled 100 times, then examined for gapping before testing to failure. Maximum load to failure, including tendon load and pinch force, was record ed for each tendon. We propose that combining the advantages of cyclical te sting and a curvilinear model is the most effective way of testing flexor t endon repairs capable of undergoing an early active motion protocol. None o f the repaired tendons failed during the cyclic portion of testing. The ave rage gapping after cycling for the 3 suture techniques was 0.12 +/- 0.35 mm for the Kessler technique, 0.00 +/- 0.00 mm for the Strickland technique, and 0.19 +/- 0.26 mm for the modified Becker technique. The maximum tendon loads to failure were 33.8 +/- 6.8 N for the Kessler technique, 30.4 +/- 5. 64 N for the Strickland technique, and 76.3 +/- 9.02 N for the modified Bec ker technique. There was a statistically significant difference between the modified Becker repair and the other 2 repa irs for maximum tendon load an d pinch force to failure. The results of th is study show that a Il 3 tendo n repair techniques can withstand forces reported with passive motion, but only the modified Becker repair allows sufficient strength above those forc es that are estimated for active motion during tendon healing. Copyright (C ) 2000 by the American Society for Surgery of the Hand.