title: Interest in the glenoid hull method for analyzing humeral subluxation in primary glenohumeral osteoarthritis.
abstract: BACKGROUND
  Posterior humeral subluxation is the main cause of failure of total shoulder arthroplasty. We aimed to compare humeral head subluxation in various reference planes and to search for a correlation with retroversion, inclination, and glenoid wear.
  
  
  METHODS
  We included 109 computed tomography scans of primary glenohumeral osteoarthritis and 97 of shoulder problems unrelated to shoulder osteoarthritis (controls); all computed tomography scans were reconstructed in the anatomic scapular plane and the glenoid hull plane that we defined. In both planes, we measured retroversion, inclination, glenohumeral offset (Walch index), and scapulohumeral offset.
  
  
  RESULTS
  Retroversion in the scapular plane (Friedman method) was lower than that in the glenoid hull plane for controls and for arthritic shoulders. The threshold of scapulohumeral subluxation was 60% and 65% in the scapular plane and glenoid hull plane, respectively. The mean upward inclination was lower in the scapular plane (Churchill method) than in the glenoid hull plane (Maurer method). In the glenoid hull plane, 35% of type A2 glenoids showed glenohumeral offset greater than 75%, with mean retroversion of 25.6° ± 6° as compared with 7.5° ± 7.2° for the "centered" type A2 glenoids (P < .0001) and an upward inclination of -1.4° ± 8° and 6.3° ± 7° (P = .03), respectively. The correlation between retroversion and scapulohumeral offset was r = 0.64 in the glenoid hull plane and r = 0.59 in the scapular plane (P < .05).
  
  
  CONCLUSIONS
  Measurement in the glenoid hull plane may be more accurate than in the scapular plane. Thus, the glenoid hull method allows for better understanding type B3 of the modified Walch classification.
authors.affiliation: Department of Orthopedic Surgery of the Upper Limb, Hand Surgery and Peripheral Nerves Surgery, Lapeyronie Hospital, Montpellier, France. Electronic address: s-bouacida@chu-montpellier.fr.
authors.forename: Soufyane
authors.initials: S
authors.lastname: Bouacida
authors.affiliation: Department of Orthopedic Surgery and Traumatology, Larchet 2 Hospital, Nice, France.
authors.forename: Marc-Olivier
authors.initials: MO
authors.lastname: Gauci
authors.affiliation: Department of Orthopedic Surgery of the Upper Limb, Hand Surgery and Peripheral Nerves Surgery, Lapeyronie Hospital, Montpellier, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Coulet
authors.affiliation: Department of Orthopedic Surgery of the Upper Limb, Hand Surgery and Peripheral Nerves Surgery, Lapeyronie Hospital, Montpellier, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Lazerges
authors.affiliation: Department of Medical Imaging, Lapeyronie Hospital, Montpellier, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Cyteval
authors.affiliation: Department of Orthopedic Surgery and Traumatology, Larchet 2 Hospital, Nice, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Boileau
authors.affiliation: Department of Orthopedic Surgery of the Upper Limb, Hand Surgery and Peripheral Nerves Surgery, Lapeyronie Hospital, Montpellier, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Chammas
mesh_terms: D000328:Adult; D000072228:Arthroplasty, Replacement, Shoulder; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D058430:Humeral Head / Q000000981:diagnostic imaging* / Q000601:surgery; D004204:Joint Dislocations / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000601:surgery; D012540:Scapula / Q000000981:diagnostic imaging* / Q000601:surgery; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Humeral subluxation; glenoid hull; glenoid inclination; glenoid retroversion; shoulder arthritis; shoulder arthroplasty