title: Biomechanical evaluation of augmentation of suture-bridge supraspinatus repair with additional anterior fixation.
abstract: BACKGROUND
  Studies have recently focused on evaluating the ability of the supraspinatus repair to withstand rotational loads. Other studies have focused on the importance of minimizing gap formation to avoid decreased healing and failure of repair. The objective of this study was to use a loading model that incorporates external rotation to biomechanically evaluate augmenting a suture-bridge technique for supraspinatus repair with an additional anterior fixation.
  
  
  METHODS
  Eight matched cadaveric shoulder pairs were randomized to 2 different types of repairs after a simulated supraspinatus tear. One group received a standard suture-bridge technique, and the other underwent a suture-bridge repair with an additional anterior fixation consisting of a 4.5-mm suture anchor. A custom apparatus was used to test all specimens, allowing for dynamic external rotation from 0° to 30° during loading. Cyclic loading was performed for 30 cycles from 0 to 90 N, followed by load to failure using a materials-testing machine.
  
  
  RESULTS
  No differences were found in linear stiffness, yield load, ultimate load, and energy absorbed for load to failure between the 2 groups (P > .05). There was a reduction in anterior gapping at ultimate load between the anterior augmentation repair group (6.4 ± 3.1 mm) and the standard suture bridge (9.4 ± 2.8 mm; P = .037).
  
  
  CONCLUSIONS
  There does not appear to be a biomechanical advantage with the addition of an anterior suture augmentation of a suture bridge for a supraspinatus repair. However, using an anterior augmentation for a suture bridge prevents gap formation at ultimate load in a biomechanical, dynamic external rotation model.
authors: Department of Orthopaedic Surgery, University of Southern California, Los Angeles, CA, USA.
authors: Ivan A
authors: IA
authors: Garcia
authors: Nickul S
authors: NS
authors: Jain
authors: Michelle H
authors: MH
authors: McGarry
authors: James E
authors: JE
authors: Tibone
authors: Thay Q
authors: TQ
authors: Lee
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D002102:Cadaver; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology; D019651:Plastic Surgery Procedures / Q000379:methods; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D053441:Suture Anchors; D013536:Suture Techniques; D013708:Tendon Injuries / Q000601:surgery*; D013718:Tensile Strength