title: Effect of anatomic bone grafting in post-traumatic recurrent anterior shoulder instability on glenoid morphology.
abstract: BACKGROUND
  Shoulder stability primarily depends on concavity compression, which relies on the concave shape of the glenoid not mere glenoid width. This study analyzed the effect of anatomic glenoid reconstruction surgery on concavity morphology.
  
  
  METHODS
  Thirty-one consecutive patients with recurrent anterior shoulder instability and glenoid bone loss underwent surgical stabilization using the J-bone graft. Twenty patients were available for preoperative, postoperative, and 1-year follow-up computed tomography scans. On standardized axial images, the change over time of the glenoid concavity extent, depth, version, and step-formation was measured and compared with the unaffected side.
  
  
  RESULTS
  The mean preoperative concavity extent was 82.3% and increased (P < .001) after surgery to 113.1% before decreasing (P < .001) to 99.2% at follow-up concordant to the contralateral side (P = .75). The mean concavity depth was 56.6% preoperatively, increased to 226.4% postoperatively (P < .001), and diminished to 149.2% at follow-up (P < .001). Affected glenoids showed an average loss of -6.0° of retroversion preoperatively, with an increase to +5.6° postoperatively (P < .001) and a decrease to +0.2° at follow-up (P < .001). The average step-formation on the articular surface after graft insertion diminished significantly, from 2.3 mm postoperatively to 0.3 mm at follow-up (P < .001).
  
  
  CONCLUSIONS
  Anatomic glenoid reconstruction surgery using the J-bone graft provides temporary overcorrection of the glenoid concavity extent, depth, and version, with subsequent normalization due to physiologic remodeling processes.
authors.affiliation: Department of Traumatology and Sports Injuries, Paracelsus Medical University, Salzburg, Austria. Electronic address: philipp.moroder@pmu.ac.at.
authors.forename: Philipp
authors.initials: P
authors.lastname: Moroder
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hitzl
authors.forename: Mark
authors.initials: M
authors.lastname: Tauber
authors.forename: Thomas
authors.initials: T
authors.lastname: Hoffelner
authors.forename: Herbert
authors.initials: H
authors.lastname: Resch
authors.forename: Alexander
authors.initials: A
authors.lastname: Auffarth
mesh_terms: D000328:Adult; D016025:Bone Transplantation / Q000379:methods*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012540:Scapula / Q000000981:diagnostic imaging / Q000601:surgery*; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Case Series; J-bone graft; Level IV; Shoulder instability; Treatment Study; glenoid bone loss; glenoid defect; glenoid reconstruction; glenoid remodeling