Epitendinous-first Zone II Flexor Tendon Repair: A Biomechanical Study
Joseph Catapano, MD1, Pooyan Abbasi, MS2, Ryan D Katz, MD3, Aviram M Giladi, MD, MS2 and Kenneth R. Means, Jr., MD2, (1)Division of Plastic and Reconstructive Surgery, University of Toronto, Toronto, ON, Canada, (2)The Curtis National Hand Center, Baltimore, MD, (3)Curtis Hand Center, The Curtis National Hand Center, Baltimore, MD
Introduction: Epitendinous flexor tendon suturing facilitates core suture placement and lessens repair bulk. Our objective was to determine whether the proposed benefits of epitendinous-first repair, including improved alignment and tensioning of the repair site, facilitates improved residual repair strength with cyclic loading as well as speed of repair as compared to core-first repair in a cadaver model.
Materials and Methods: In fresh human cadaver hands, we exposed the flexor digitorum profundus (FDP) tendon between the A2 and A4 pulleys and made a transverse laceration in the tendon. Each matched-pair FDP was repaired by a solo surgeon with a running-locking epitendinous suture using 6-0 prolene and a locking cruciate 8-strand core-suture repair using 4-0 fibreloop, with either the epitendinous-first (n = 12) or the core suture-first (n = 12). Via a computer-controlled load-generator attached to the finger flexor and extensor tendons, each repaired tendon had cylic loading with full finger extension to tip-to-palm flexion at 0.2 Hz for 2,000 cycles. Repair failure during cyclic loading was defined as gap formation >2 millimeters. The repairs that had not failed by 2,000 cycles were then loaded to failure at 1 mm/s. Our primary outcome was residual load-to-failure after cyclic loading.
Results: One core suture-first repair failed during cyclic loading (P>0.05). There was no significant difference in residual mean load-to-failure between epitendinous-first and core suture-first repair (97.5 vs. 91.3 N, P>0.05). There was also no significant difference in mean repair time (15.3 vs 13.4 min, P>0.05).
Conclusions: With a transverse zone II FDP laceration, the order of epitendinous suture placement does not significantly impact repair speed or residual strength after cyclic loading. Further investigation may be beneficial to determine whether epitendinous-first repair influences repair strength and repair speed for non-transverse lacerations where tendon alignment and tensioning may be more challenging.
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