title: Inter-rater reliability of an arthritic glenoid morphology classification system.
abstract: To our knowledge, no independent analysis of the inter-rater agreement of the widely used Walch classification for osteoarthritic glenoid morphology has been performed. The computed tomography scans of 24 shoulders with primary osteoarthritis were used by 4 experienced shoulder surgeons to classify the glenoids independently according to Walch et al. The weighted kappa statistic was calculated to determine the inter-rater and intrarater agreement among observers. The overall inter-rater agreement for the Walch classification was fair (kappa = 0.37) when classified into the 5 types (A1, A2, B1, B2, and C). Agreement for the various subclassifications was as follows: A1, kappa = 0.22; A2, kappa = 0.33; B1, kappa = 0.17; B2, kappa = 0.32; and C, kappa = 0.86. When the classification system was simplified to just the 3 major types (A, B, and C), overall agreement was moderate (kappa = 0.44). Agreement for each type was moderate for A (kappa = 0.59) and B (kappa = 0.59) and almost perfect for C (kappa = 0.89). Overall intrarater agreement was fair (kappa = 0.37). We conclude that only fair agreement was found among experienced shoulder surgeons when classifying arthritic shoulders using the classification system of Walch et al. A glenoid classification scheme that relies more upon glenoid morphology and less upon humeral head position may demonstrate greater observer agreement and, therefore, may offer greater value.
authors.affiliation: The CORE Institute, 14420W Meeker Blvd, Suite 300, Sun City West, AZ 85375, USA. jason.scalise@thecoreinstitute.com
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Scalise
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Codsi
authors.forename: John J
authors.initials: JJ
authors.lastname: Brems
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Iannotti
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000145:classification* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010003:Osteoarthritis / Q000145:classification* / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012785:Shoulder Joint / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed