title: Restoration of anterior glenoid bone defects in posttraumatic recurrent anterior shoulder instability using the J-bone graft shows anatomic graft remodeling.
abstract: BACKGROUND
  The J-bone graft technique has previously been reported for anatomic restoration of the bony glenoid surface in cases of posttraumatic recurrent anterior shoulder instability with significant glenoid bone loss.
  
  
  OBJECTIVE
  To analyze the physiological remodeling process of the J-bone graft over time.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Thirty-one consecutive patients treated with anatomic glenoid restoration surgery using the J-bone graft for posttraumatic recurrent anterior shoulder instability with a significant bony glenoid defect were included in this study. Twenty patients received 3-dimensional computed tomography scans of the affected shoulder preoperatively, postoperatively, and at 1-year follow-up. On "en face" views of the glenoid, the change over time of the glenoid diameter, glenoid area, and glenoid defect size in relation to a best-fit circle indicating 100% was measured.
  
  
  RESULTS
  The average glenoid diameter increased from 81.0% preoperatively to 110.4% postoperatively (P < .001). At 1-year follow-up, the diameter had decreased significantly to 100.6% (P < .001), which is concordant to a theoretical perfect glenoid diameter of 100% (P = .73). The average glenoid surface area increased from 80.8% preoperatively to 110.0% postoperatively (P < .001). At 1-year follow-up, a decrease to 102.2% (P < .005) was measured, which again is close to a theoretical perfect glenoid surface area of 100% (P = .15). By applying the J-bone graft, the average missing surface area of the glenoid was reduced from 19.2% preoperatively to 3.9% postoperatively (P < .001). At 1-year follow-up, an average of 3.6% was calculated, indicating no statistically significant change over time (P = .90).
  
  
  CONCLUSIONS
  Anatomic glenoid reconstructive surgery using the J-bone graft technique benefits from a physiological remodeling process, molding the bone graft closely into the original shape of an uninjured anterior glenoid rim. While parts of the graft lying inside the projected former surface area of the glenoid are preserved, the parts lying outside are resorbed over time, suggestive of strain-adapted graft remodeling.
authors.affiliation: Department of Traumatology and Sports Injuries, Paracelsus Medical University, Muellner Hauptstrasse 48, Salzburg, 5020 Austria. philipp.moroder@pmu.ac.at
authors.forename: Philipp
authors.initials: P
authors.lastname: Moroder
authors.forename: Corinna
authors.initials: C
authors.lastname: Hirzinger
authors.forename: Stefan
authors.initials: S
authors.lastname: Lederer
authors.forename: Nicholas
authors.initials: N
authors.lastname: Matis
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hitzl
authors.forename: Mark
authors.initials: M
authors.lastname: Tauber
authors.forename: Herbert
authors.initials: H
authors.lastname: Resch
authors.forename: Alexander
authors.initials: A
authors.lastname: Auffarth
mesh_terms: D016723:Bone Remodeling; D016025:Bone Transplantation / Q000379:methods*; D061165:Glenoid Cavity / Q000000981:diagnostic imaging / Q000293:injuries / Q000502:physiology* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D019637:Orthopedic Procedures / Q000379:methods*; D016059:Range of Motion, Articular; D012008:Recurrence; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000502:physiology / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D014182:Transplantation, Autologous