title: Effect of lesser tuberosity osteotomy size and repair construct during total shoulder arthroplasty.
abstract: BACKGROUND
  Lesser tuberosity osteotomy has been shown to decrease postoperative subscapularis dysfunction. The purpose of this study was to determine the effect of osteotomy thickness and suture configuration on repair integrity.
  
  
  METHODS
  One side of 12 matched-pair cadaveric shoulders was randomly assigned to either a thick osteotomy (100% of lesser tuberosity height) or a thin osteotomy (50% of height). Both sides of the matched pairs were given the same repair, either (1) compression sutures or (2) compression sutures plus 1 tension suture. This created 4 groups of 6 paired specimens. Computed tomography imaging was used to measure tuberosity dimensions before and after osteotomy to validate fragment height and area. The repairs were loaded cyclically and then loaded to failure. A video system measured fragment displacement. The percent area of osteotomy contact was calculated from the computed tomography and displacement data.
  
  
  RESULTS
  The average initial displacement was less in the thin osteotomy groups (P = .011). Adding a tension suture negated this difference. A significant number of thin repair sites compared with thick repair sites remained intact during load-to-failure testing (P = .001). No difference occurred because of maximum load between the repair groups (P = .401), and construct stiffness was greater when a tension suture was used (P = .032). The percent area of osteotomy contact showed no differences between the osteotomy (P = .431) and repair (P = .251) groups.
  
  
  CONCLUSIONS
  The study showed that thin osteotomies displaced less than thick osteotomies. Adding a tension band improved construct stability and eliminated some failure modes. Our ideal repair was a thin wafer with both tension and compression sutures. This construct had smaller total displacement, a high osteotomy percent contact area, and a high maximum load.
authors.affiliation: Orthopaedic Specialists - UPMC, Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. Electronic address: cschmidthand@comcast.net.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Schmidt
authors.affiliation: Upper Extremity Reconstructive Surgery, The Emory Orthopaedic Center, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Claude D
authors.initials: CD
authors.lastname: Jarrett
authors.affiliation: Department of Mechanical Engineering and Material Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Allegheny General Biomechanics Laboratory, Pittsburgh, PA, USA.
authors.forename: Brandon T
authors.initials: BT
authors.lastname: Brown
authors.affiliation: North Louisiana Orthopaedic and Sports Medicine Clinic, Monroe, LA, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: DeGravelle
authors.affiliation: Department of Orthopaedic Surgery and Sports Medicine, Essentia Health, Fargo, ND, USA.
authors.forename: Prasad
authors.initials: P
authors.lastname: Sawardeker
authors.affiliation: Department of Mechanical Engineering and Material Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Allegheny General Biomechanics Laboratory, Pittsburgh, PA, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Weir
authors.affiliation: Department of Radiology, Allegheny General Hospital, Pittsburgh, PA, USA.
authors.forename: Carmen R
authors.initials: CR
authors.lastname: Latona
authors.affiliation: Department of Mechanical Engineering and Material Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Allegheny General Biomechanics Laboratory, Pittsburgh, PA, USA.
authors.forename: Mark Carl
authors.initials: MC
authors.lastname: Miller
mesh_terms: D019643:Arthroplasty, Replacement / Q000379:methods*; D002102:Cadaver; D005260:Female; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods; D011897:Random Allocation; D012785:Shoulder Joint / Q000601:surgery*; D013536:Suture Techniques; D014057:Tomography, X-Ray Computed
keywords: Basic Science Study; Biomechanics; Cadaveric Model; Total shoulder arthroplasty; biomechanics; compression sutures; lesser tuberosity osteotomy repair; lesser tuberosity thickness; subscapularis repair; tension-band sutures