title: Increasing pullout strength of suture anchors in osteoporotic bone using augmentation--a cadaver study.
abstract: BACKGROUND
  Rotator cuff tears are of increasing clinical impact in the physically active elderly patients. Recent research revealed, that a high percentage of these patients present with significant loss of bone mineral density at the insertion site of the rotator cuff, thereby compromising suture anchorage for operative repair. We therefore hypothesized that augmentation of suture anchors improves biomechanical properties in low bone quality.
  
  
  METHODS
  28 osteoporotic humeral heads were included in this biomechanical study. Bone quality at the anchor insertion sites (group 1: posterior-medial; group 2: anterior-lateral) within the greater tuberosity was analyzed using HR-pQCT (voxel size: 82μm). Anchor positions of identical quality were then randomized to either conventional screw anchorage or polymethylmethacrylat augmented screw anchorage. All anchors were cyclically ramp-loaded until pullout.
  
  
  RESULTS
  Pullout strength accounted for 226N in group I for conventional anchorage and for 332N in augmented technique. In group 2 (anterior-lateral) the pullout strength was 209N (conventional) and 304N (augmented). Pull-out strength of augmented screw anchors was significantly higher in both groups (p<0.05).
  
  
  CONCLUSIONS
  Compared to conventional insertion techniques, the cement augmentation technique increases the pullout strength of suture anchors in low bone quality significantly. Cement augmentation could therefore be a helpful tool for improved suture anchor stability, especially in locations of low bone quality.
authors: OrthoPlus-Muenchen, Germany; Department of Orthopedic Surgery and Traumatology, Ludwig-Maximilians-Universitaet, Muenchen, Germany.
authors: Volker
authors: V
authors: Braunstein
authors: Department of Orthopedic Surgery and Traumatology, Ludwig-Maximilians-Universitaet, Muenchen, Germany.
authors: Ben
authors: B
authors: Ockert
authors: AO Research Institute, AO Foundation, Davos, Switzerland.
authors: Markus
authors: M
authors: Windolf
authors: AO Research Institute, AO Foundation, Davos, Switzerland.
authors: Christoph M
authors: CM
authors: Sprecher
authors: Department of Orthopedic Surgery and Traumatology, Ludwig-Maximilians-Universitaet, Muenchen, Germany.
authors: Wolf
authors: W
authors: Mutschler
authors: Department of Sports Orthopedics, Technische Universitaet, Muenchen, Germany.
authors: Andreas
authors: A
authors: Imhoff
authors: Department of Trauma Surgery, Technische Universitaet, Muenchen, Germany.
authors: Lukas Karl Leo
authors: LK
authors: Postl
authors: Department of Trauma Surgery, Technische Universitaet, Muenchen, Germany.
authors: Peter
authors: P
authors: Biberthaler
authors: Department of Trauma Surgery, Technische Universitaet, Muenchen, Germany. Electronic address: Chlodwig.Kirchhoff@mri.tum.de.
authors: Chlodwig
authors: C
authors: Kirchhoff
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001843:Bone Cements; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D006801:Humans; D058430:Humeral Head / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D010024:Osteoporosis / Q000503:physiopathology / Q000601:surgery*; D019904:Polymethyl Methacrylate; D017006:Rotator Cuff / Q000601:surgery; D053441:Suture Anchors; D013718:Tensile Strength
chemical_list: D001843:Bone Cements; D019904:Polymethyl Methacrylate
keywords: Arthroscopy; BMD; Cement augmentation; HR-pQCT; Osteoporosis; Pullout strength; Rotator cuff repair; Suture anchor