title: Trans-subscapularis portal versus low-anterior portal for low anchor placement on the inferior glenoid fossa: a cadaveric shoulder study with computed tomographic analysis.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the accuracy of inserting a glenoid anchor at the 5:30 clockface position using a trans-subscapularis (TSS) portal versus a low anterior (LA) portal.
  
  
  METHODS
  Five surgeons (T.D., J.C., C.V., D.J.O-H., J.S.T.) placed a single anchor in 20 fresh-frozen cadaveric shoulders. In each of 2 shoulders, surgeons used an LA portal to insert the anchor, whereas in 2 shoulders a TSS portal was used. Surgeons were directed to place the anchor at the 5:30 position at an angle 45° to the glenoid surface (axial plane) and passing perpendicular to the glenoid rim in the coronal plane. Shoulders were then dissected and computed tomographic (CT) scans obtained. Anchor position relative to the clockface was documented by 2 blinded assessors, as was the angle of insertion in the axial and coronal planes. Statistical significance was calculated with a Student t test for paired samples (confidence interval [CI], 95%; significance, P < .05).
  
  
  RESULTS
  The average deviation from the 5:30 position was 48 minutes (standard deviation [SD], 31 minutes) for the LA portal (average position, 4:42 o'clock) versus 28.5 minutes (SD, 19 minutes) for the TSS group (average position, 5:02 o'clock) (P = .15). The average angle of anchor insertion in the axial plane was 67.2° (SD, 19°) for the LA portal versus 62.8° (SD, 14°) for the TSS portal (P = .49), whereas the average angle of insertion in the coronal plane was 31.3° (SD, 14°) of inferior angulation in the LA group and 14.3° (SD, 8°) of inferior angulation in the TSS group (P = .009). Of the anchors inserted, 9 of 20 (45%) showed evidence of far-cortical perforation. No difference in cortical perforation was seen between the 2 portals, with perforation more likely with anchors inserted greater than 45° in the axial plane (8 of 20) than with those inserted less than 45° (1 of 20) (P = .02).
  
  
  CONCLUSIONS
  The use of a TSS portal improves the angle of approach to the inferior glenoid rim in comparison with an LA portal, reducing the acuity of the angle of insertion in the coronal plane.
  
  
  CONCLUSIONS
  The TSS portal is an option for surgeons performing arthroscopic Bankart repair using anchors low on the glenoid rim.
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada. Electronic address: tim.dwyer@wchospital.ca.
authors.forename: Tim
authors.initials: T
authors.lastname: Dwyer
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Massimo
authors.initials: M
authors.lastname: Petrera
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: White
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Ofir
authors.initials: O
authors.lastname: Chechik
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Wasserstein
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Jaskarndip
authors.initials: J
authors.lastname: Chahal
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Veillette
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Darrell J
authors.initials: DJ
authors.lastname: Ogilvie-Harris
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: John S
authors.initials: JS
authors.lastname: Theodoropoulos
mesh_terms: D001182:Arthroscopy / Q000379:methods*; D002102:Cadaver; D061165:Glenoid Cavity / Q000601:surgery*; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D012540:Scapula / Q000000981:diagnostic imaging / Q000601:surgery; D012785:Shoulder Joint / Q000601:surgery*; D053441:Suture Anchors; D014057:Tomography, X-Ray Computed