title: Initial load-to-failure and failure analysis in single- and double-row repair techniques for rotator cuff repair.
abstract: OBJECTIVE
  This experimental study aimed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture materials. Additionally, the mode of failure of each repair was evaluated.
  
  
  METHODS
  In 32 sheep shoulders, a standardized tear of the infraspinatus tendon was created. Then, n = 8 specimen were randomized to four repair methods: (1) Double-row Anchor Ethibond coupled with polyester sutures, USP No. 2; (2) Double-Row Anchor HiFi with polyblend polyethylene sutures, USP No. 2; (3) Single-Row Anchor Ethibond coupled with braided polyester sutures, USP No. 2; and (4) Single-Row Anchor HiFi with braided polyblend polyethylene sutures, USP No. 2. Arthroscopic Mason-Allen stitches were placed (single-row) and combined with medial horizontal mattress stitches (double-row). All specimens were loaded to failure at a constant displacement rate on a material testing machine.
  
  
  RESULTS
  Group 4 showed lowest load-to-failure result with 155.7 +/- 31.1 N compared to group 1 (293.4 +/- 16.1 N) and group 2 (397.7 +/- 7.4 N) (P < 0.001). Stiffness was highest in group 2 (162 +/- 7.3 N/mm) and lowest in group 4 (84.4 +/- 19.9 mm) (P < 0.001). In group 4, the main cause of failure was due to the suture cutting through the tendon (n = 6), a failure case observed in only n = 1 specimen in group 2 (P < 0.001).
  
  
  CONCLUSIONS
  A double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used.
authors.affiliation: Department of Orthopaedic Surgery, University of Göttingen Medical Centre, Georg-August-University, Robert-Koch-Street 40, Göttingen, Germany. mbaums@t-online.de
authors.forename: M H
authors.initials: MH
authors.lastname: Baums
authors.forename: G H
authors.initials: GH
authors.lastname: Buchhorn
authors.forename: F
authors.initials: F
authors.lastname: Gilbert
authors.forename: G
authors.initials: G
authors.lastname: Spahn
authors.forename: W
authors.initials: W
authors.lastname: Schultz
authors.forename: H-M
authors.initials: HM
authors.lastname: Klinger
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D019245:Compressive Strength; D019544:Equipment Failure Analysis; D023421:Models, Animal; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods*; D011897:Random Allocation; D012307:Risk Factors; D017006:Rotator Cuff / Q000502:physiology / Q000601:surgery*; D012756:Sheep; D012785:Shoulder Joint / Q000601:surgery; D013314:Stress, Mechanical; D053441:Suture Anchors; D013536:Suture Techniques; D016474:Weight-Bearing