title: Arthroscopically assisted fixation of glenoid fractures: a cadaver study to show potential applications of percutaneous screw insertion and anatomic risks.
abstract: BACKGROUND
  Displaced glenoid fractures require reduction and internal fixation to avoid chronic instability or degenerative changes. Arthroscopically assisted percutaneous fixation has been performed successfully for such fractures, avoiding extensive surgical dissection. To assess the application of this new technique, our cadaveric study was designed to show 1) the safe zones of percutaneous screw insertion and 2) the position of bony obstructions to the glenoid.
  
  
  METHODS
  In 18 cadaver shoulders, we performed arthroscopically assisted percutaneous wire insertion into the glenoid using anterior, superior, and posterior approaches. After dissection, distances from wires to the relevant neurovascular structures were recorded, and 95% confidence intervals were calculated. A safe distance was defined as 15 mm. The entry point of each wire and angle of insertion relative to the glenoid clock face was also recorded.
  
  
  RESULTS
  Superior and posterior percutaneous approaches appear to be safe, with minimal risk to the suprascapular vessels and axillary nerve, respectively. The anterior approach injured the cephalic vein in 30% of specimens, and there was a clinically significant risk to the musculocutaneous nerve and inferior branch of the suprascapular nerve. The superior portion of the glenoid is accessible by percutaneous screw insertion between the clock times 7:40 and 2:50, apart from positions occupied by the coracoid (1:05-2:00) and acromion (9:35-10:55).
  
  
  CONCLUSIONS
  Arthroscopic fixation of complex glenoid fractures has had good outcomes in clinical case studies. This cadaveric study shows that percutaneous screw insertion is safe via superior and posterior approaches and feasible for a range of fracture configurations.
authors.affiliation: International Center for Orthopaedic Advancement, The Johns Hopkins Bayview Medical Center, Baltimore, MD 21224-2780, USA. ehenze1@jhmi.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Marsland
authors.forename: Hasan A
authors.initials: HA
authors.lastname: Ahmed
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy / Q000379:methods; D001863:Bone Screws; D002102:Cadaver; D004210:Dissection; D005260:Female; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011859:Radiography; D000070636:Rotator Cuff Injuries; D012784:Shoulder Fractures / Q000601:surgery*; D012785:Shoulder Joint / Q000000981:diagnostic imaging*