title: Biomechanical comparison of double-row versus transtendon single-row suture anchor technique for repair of the grade III partial articular-sided rotator cuff tears.
abstract: BACKGROUND
  For partial-thickness tears of the rotator cuff, double-row fixation and transtendon single-row fixation restore insertion site anatomy, with excellent results. We compared the biomechanical properties of double-row and transtendon single-row suture anchor techniques for repair of grade III partial articular-sided rotator cuff tears.
  
  
  METHODS
  In 10 matched pairs of fresh-frozen sheep shoulders, the infraspinatus tendon from 1 shoulder was repaired with a double-row suture anchor technique. This comprised placement of 2 medial anchors with horizontal mattress sutures at an angle of ≤ 45° into the medial margin of the infraspinatus footprint, just lateral to the articular surface, and 2 lateral anchors with horizontal mattress sutures. Standardized, 50% partial, articular-sided infraspinatus lesions were created in the contralateral shoulder. The infraspinatus tendon from the contralateral shoulder was repaired using two anchors with transtendon single-row mattress sutures. Each specimen underwent cyclic loading from 10 to 100 N for 50 cycles, followed by tensile testing to failure. Gap formation and strain over the footprint area were measured using a motion capture system; stiffness and failure load were determined from testing data.
  
  
  RESULTS
  Gap formation for the transtendon single-row repair was significantly smaller (P < 0.05) when compared with the double-row repair for the first cycle ((1.74 ± 0.38) mm vs. (2.86 ± 0.46) mm, respectively) and the last cycle ((3.77 ± 0.45) mm vs. (5.89 ± 0.61) mm, respectively). The strain over the footprint area for the transtendon single-row repair was significantly smaller (P < 0.05) when compared with the double-row repair. Also, it had a higher mean ultimate tensile load and stiffness.
  
  
  CONCLUSIONS
  For grade III partial articular-sided rotator cuff tears, transtendon single-row fixation exhibited superior biomechanical properties when compared with double-row fixation.
authors.affiliation: Department of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning 116001, China.
authors.forename: Chun-Gang
authors.initials: CG
authors.lastname: Zhang
authors.forename: De-Wei
authors.initials: DW
authors.lastname: Zhao
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Wang
authors.forename: Ming-Fa
authors.initials: MF
authors.lastname: Ren
authors.forename: Rui-Xin
authors.initials: RX
authors.lastname: Li
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.forename: Yu-Peng
authors.initials: YP
authors.lastname: Liu
mesh_terms: D000818:Animals; D019637:Orthopedic Procedures / Q000379:methods*; D017006:Rotator Cuff / Q000601:surgery*; D012756:Sheep; D053441:Suture Anchors