title: Cyclic loading of rotator cuff repairs: an in vitro biomechanical comparison of bioabsorbable tacks with transosseous sutures.
abstract: OBJECTIVE
  This study compares rotator cuff repair strength after cyclic loading of bioabsorbable tacks and traditional transosseous sutures, and correlates the results with bone density, age, and gender. The hypotheses were that tack repair strength would be inferior to transosseous sutures and that repair strength would be directly related to bone quality.
  
  
  METHODS
  In vitro randomized biomechanical study.
  
  
  METHODS
  Eight paired cadaveric shoulders with a standardized supraspinatus defect were randomized to tack or suture repair and subjected to step-wise cyclic loading. Repair migration was measured by quantifying the motion of markers affixed to tendon and bone using a digital camera. Failure mode, cycles, and load were measured for 50% and 100% loss of repair. Results were correlated with bone density, age, and gender.
  
  
  RESULTS
  Tack repairs failed at the tack-tendon interface, whereas suture rupture was the mode of failure for the suture repairs. Mean values for 50% loss of repair were 206 +/- 88 cycles and 44 +/- 15 N for the sutures, and 1,193 +/- 252 cycles and 156 +/- 20 N for the tacks (P < .05). The corresponding values for 100% loss of repair were 2,458 +/- 379 cycles and 294 +/- 27 N for the sutures, and 2,292 +/- 333 cycles and 263 +/- 28 N for the tacks (P > .05). These results did not correlate with bone density, age, or gender.
  
  
  CONCLUSIONS
  This study has shown that bioabsorbable tacks provide improved repair strength in comparison with traditional suture techniques. Repair strength did not correlate with bone quality, and this may be attributed to failure primarily through the repair construct or at the tack-tendon interface and not through bone. This report describes a new high-resolution optical method of measuring tendon repair strength that should be a useful model for future studies.
  
  
  CONCLUSIONS
  This study demonstrates the biomechanical advantages of a sutureless tack device for rotator cuff repair compared with a traditional augmented suture repair technique.
authors: Department of Surgery, University of Western Ontario, London, Ontario, Canada.
authors: Ryan T
authors: RT
authors: Bicknell
authors: Chris
authors: C
authors: Harwood
authors: Louis
authors: L
authors: Ferreira
authors: Graham J W
authors: GJ
authors: King
authors: James A
authors: JA
authors: Johnson
authors: Ken
authors: K
authors: Faber
authors: Darren
authors: D
authors: Drosdowech
mesh_terms: D020341:Absorbable Implants; D000368:Aged; D001696:Biomechanical Phenomena; D015519:Bone Density; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D013537:Sutures; D016474:Weight-Bearing