SCIENTIFIC ARTICLE Biomechanical Comparison of Techniques to Reduce the Bulk of Lacerated Flexor Tendon Ends Within Digital Sheaths of the Porcine Forelimb M. Vigler, MD, S. K. Lee, MD, R. Palti, MD, J. C. Williams, MD, A. J. Kaminsky, MPH, M. A. Posner, MD, M. R. Hausman, MD Purpose Zone II flexor tendon repairs may create a bulging effect with increased bulk and resistance to tendon gliding. A biomechanical time 0 study was performed to assess 2 methods of tendon antibulking for work of flexion and strength characteristics. Methods We placed 24 fresh-frozen porcine forelimb tendons in a custom jig. Deep flexor tendon was sectioned just distal to the intact A1 and A2 pulleys. Specimens were divided into 3 groups before repair: group 1, nonmodified tendon; group 2, 30° bilateral notch excised from both tendon ends; and group 3, triangular longitudinal central wedge excised from both tendon ends. All repairs used a 4-strand modified Kessler core suture and running circumferential epitendinous suture. Work of flexion, 2-mm gap formation, and ultimate load to failure were tested. Results Both antibulking techniques (groups 2 and 3) had significantly less work of flexion than group 1 (36.3 and 34.9 J vs 142.9 J, p  .001). There was no significant change in work of flexion between groups 2 and 3 (p  .05). There was no significant difference in terms of 2-mm gap formation among the 3 groups (p  .05). Groups 1 and 3 exhibited a significantly higher load to failure compared with group 2 (p  .05). Conclusions The antibulking repair techniques used in this study decrease the work of flexion with no significant change in force to 2-mm gap formation. Group 2, however, did have significantly lower load to failure. These techniques might be beneficial in zone II flexor tendon injury, in which the tight annular pulley system restricts tendon gliding. However, this is a time 0 study and the potential adverse effects of increase tendon manipulation and trauma were not analyzed, which might increase adhesions and scar during the healing phase of tendon repair. (J Hand Surg 2009;34A:1653 –1658. Copyright © 2009 by the American Society for Surgery of the Hand. All rights reserved.) Key words Flexor, tendon, repair, antibulking, biomechanical. S TERLING BUNNELL REFERRED TO the flexor digital sheath in fingers as “no man’s land” and cau- tioned surgeons about repairing tendons within it because of the likelihood of scarring resulting in limited tendon excursion. 1 An immediate problem after a ten- don repair in the sheath is bulging or flaring of each tendon end that leads to increased resistance to gliding (increased work of flexion). The objectives of our in vitro study were to evaluate 2 different antibulking techniques and to compare the work of flexion and From the Department of Orthopedic Surgery, Mount Sinai Medical Center; and the Division of Hand Sur- gery, Department of Orthopedic Surgery, NYU Hospital for Joint Diseases, New York, NY. Received for publication June 30, 2008; accepted in revised form June 29, 2009. The authors thank Karl Jepsen, PhD, of the Orthopedic Research Laboratory at Mount Sinai School of Medicine for use of laboratory equipment, as well as Mathew Cordova, MD, for assistance. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Mordechai Vigler, MD, Department of Orthopedic Surgery, Mount Sinai Medical Center, New York, 1343 E 31st Street, Brooklyn, NY 11210; e-mail: drvigler@gmail.com. 0363-5023/09/34A09-0010$36.00/0 doi:10.1016/j.jhsa.2009.06.028 ©  ASSH  Published by Elsevier, Inc. All rights reserved.  1653