title: The biomechanical performance of a new forked knotless biceps tenodesis compared to a knotless and suture anchor tenodesis.
abstract: OBJECTIVE
  Biomechanical comparison of three different fixation techniques for a proximal biceps tenodesis.
  
  
  METHODS
  Eighteen human cadaver specimens were used for the testing. A tenodesis of the proximal biceps tendon was performed using a double-loaded suture anchor (5.5-mm Corkscrew, Arthrex), a knotless anchor (5.5-mm SwiveLock, Arthrex) or a forked knotless anchor (8-mm SwiveLock, Arthrex). Reconstructions were cyclically loaded for 50 cycles from 10-60 to 10-100 N. Cyclic displacement and ultimate failure loads were determined, and mode of failure was evaluated.
  
  
  RESULTS
  Cyclic displacement at 60 N revealed a mean of 3.3 ± 1.1 mm for the Corkscrew, 5.4 ± 1.4 mm for the 5.5-mm SwiveLock and 2.9 ± 1.6 mm for the 8-mm forked SwiveLock. At 100 N, 5.1 ± 2.2 mm were seen for the Corkscrew anchor, 8.7 ± 2.5 mm for the 5.5-mm SwiveLock and 4.8 ± 3.3 mm for the 8-mm forked SwiveLock anchor. Significant lower cyclic displacement was seen for the Corkscrew anchor (p < 0.020) as well as the 8-mm SwiveLock anchor (p < 0.023) compared to the 5.5-mm SwiveLock anchor at 60 N. An ultimate load to failure of 109 ± 27 N was found for the Corkscrew anchor, 125 ± 25 N were measured for the 5.5-mm SwiveLock anchor, and 175 ± 42 N were found for the 8-mm forked SwiveLock anchor. Significant differences were seen between the 8-mm SwiveLock compared to the 5.5-mm SwiveLock (p < 0.044) as well as the Corkscrew anchor (p < 0.009). No significant differences were seen between the Corkscrew and the 5.5-mm SwiveLock anchor.
  
  
  CONCLUSIONS
  The new 8-mm forked SwiveLock anchor significantly enhances construct stability compared to a 5.5-mm double-loaded Corkscrew anchor as well as the 5.5-mm SwiveLock suture anchor. However, a restrictive postoperative rehabilitation seems to be important in all tested reconstructions in order to avoid early failure of the construct.
authors.affiliation: Department of Orthopedic Surgery, Saarland University, Kirrberger Str., Geb. 37, 66421, Homburg (Saar), Germany. olaf.lorbach@gmx.de.
authors.forename: Olaf
authors.initials: O
authors.lastname: Lorbach
authors.affiliation: Department of Orthopedic Surgery, Saarland University, Kirrberger Str., Geb. 37, 66421, Homburg (Saar), Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Trennheuser
authors.affiliation: Department of Orthopedic Surgery, Saarland University, Kirrberger Str., Geb. 37, 66421, Homburg (Saar), Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Kohn
authors.affiliation: Department of Orthopedic Surgery, Saarland University, Kirrberger Str., Geb. 37, 66421, Homburg (Saar), Germany.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Anagnostakos
mesh_terms: D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D008422:Materials Testing; D011474:Prosthesis Design; D012782:Shoulder / Q000601:surgery; D053441:Suture Anchors; D013536:Suture Techniques; D053656:Tenodesis / Q000295:instrumentation* / Q000379:methods
keywords: Biceps; Cyclic loading; Suture anchor; Tenodesis