title: A biomechanical comparison of multistrand flexor tendon repairs using an in situ testing model.
abstract: An in situ testing model was used to evaluate the performance of zone II flexor tendon repairs and to compare the biomechanical properties of 4-strand repairs with 2- and 6-strand repairs. Fifty digits from human cadaveric hands were mounted in a custom apparatus for in situ tensile testing. Intratendinous metallic markers were placed so that gap formation could be determined by fluoroscopy during tensile testing. Three 4-strand repairs (the 4-strand Kessler, the cruciate, and a locked modification of the cruciate repair) were compared with the 2-strand Kessler and the 6-strand Savage repairs. Ultimate tensile strength, load at 2-, 3-, and 4-mm gap formation, and work of flexion were determined. Work of flexion, while increased for the multistrand repairs, did not show a statistically significant correlation with the number of strands crossing the repair site. The tensile strength of the 6-strand repair was significantly greater than each of the 2- or 4-strand repairs. The tensile strength of all 4-strand repairs was significantly greater than the 2-strand repair. The 6-strand repair and the 2 cruciate repairs demonstrated a statistically increased resistance to gap formation compared with the 2-strand Kessler repair, but notably there was no statistically significant difference in gap resistance between the 2and 4-strand Kessler repairs. This in situ tensiletesting protocol demonstrated that 4- and 6-strand repairs have adequate initial strength to withstand the projected forces of early active motion protocols. Three of the 4 multistrand repairs demonstrated improved gap resistance compared with the 2-strand repair. The presence of the second suture in the Kessler configuration significantly increases its strength but not its gap resistance.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Barrie
authors.forename: S W
authors.initials: SW
authors.lastname: Wolfe
authors.forename: C
authors.initials: C
authors.lastname: Shean
authors.forename: D
authors.initials: D
authors.lastname: Shenbagamurthi
authors.forename: J F
authors.initials: JF
authors.lastname: Slade
authors.forename: M M
authors.initials: MM
authors.lastname: Panjabi
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D002102:Cadaver; D017629:Gap Junctions / Q000502:physiology*; D006801:Humans; D008663:Metacarpus / Q000502:physiology; D008954:Models, Biological; D011336:Probability; D013314:Stress, Mechanical; D013536:Suture Techniques; D013537:Sutures; D013710:Tendons / Q000601:surgery*; D013718:Tensile Strength; D014945:Wound Healing / Q000502:physiology