title: Biomechanical comparison of the primary stability of suturing Achilles tendon rupture: a cadaver study of Bunnell and Kessler techniques under cyclic loading conditions.
abstract: BACKGROUND
  Biomechanical studies investigating suture techniques for Achilles tendon repair used single load to failure tests in order to evaluate the maximal load capacity of the repaired construct. During early rehabilitation the repair is repetitively loaded such as exercise or daily living activities like walking. Cyclic loading seems to duplicate the physiological loading conditions more closely than single cycle failure tests. Aim of this study was to test the most commonly used Achilles tendon repair techniques (Bunnell and Kessler repair) under cyclic loading conditions.
  
  
  METHODS
  Following tenotomy fresh human cadaveric tendons were sutured either with the Bunnell or Kessler technique. After repair, cyclic loading tests were performed with a uniaxial biomechanical testing machine Lloyd LR-5K Plus. Both groups were sutured with 0.7 mm PDS.
  
  
  RESULTS
  Except at maximum load we could not find significant differences between tendons sutured by Bunnell and Kessler techniques. During the cyclic testing there were no differences between both groups with respect to displacement. This applies also to the stiffness of the constructs, which we defined from the load to failure measurements. The failure modes in both groups differed; the tendons repaired by Kessler technique were cut by the tendons and in the Bunnell group the suture material tore in each specimen tested.
  
  
  CONCLUSIONS
  In our study Bunnell and Kessler techniques showed similar biomechanical properties using the same suture material. The typical failure mode of the Bunnell technique shows potential to optimise biomechanical behavior by using stronger suture material.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Westfaelische, Wilhelms, University Muenster, Waldeyerstrasse 1, 48149, Munster, Germany. mirco.herbort@ukmuenster.de
authors.forename: Mirco
authors.initials: M
authors.lastname: Herbort
authors.forename: Axel
authors.initials: A
authors.lastname: Haber
authors.forename: Thore
authors.initials: T
authors.lastname: Zantop
authors.forename: Georg
authors.initials: G
authors.lastname: Gosheger
authors.forename: Steffen
authors.initials: S
authors.lastname: Rosslenbroich
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Raschke
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
mesh_terms: D000125:Achilles Tendon / Q000293:injuries* / Q000601:surgery*; D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D012421:Rupture / Q000601:surgery; D013536:Suture Techniques; D013718:Tensile Strength