Purpose: Recognition of the glenoid version is important for evaluation of different pathologies. There is no consensus on method to use to evaluate version. The purpose of this study was to compare different measurement strategies in one hundred-sixteen (116) patients with shoulder CT-scans.

Method: Scapula CT-scan axial images were revised and the cut below the base of the coracoid was selected. The glenoid version was measured according to the Friedman method (FM) and the “scapula body” methods (BM). In case of B2 glenoid three different reference lines have been measure: the neo-glenoid NG (posterior erosion surface), paleo-glenoid PG (original glenoid surface) and the intermediate-glenoid IG (line from anterior and posterior edge). Three orthopaedic surgeons independently examined the images two times and intra/inter-observer reliability was calculated using Intra-Class Correlation (ICC). The objective of this paper is to define which method shows best reliability.

Results: Group 1 (B2 excluded n=53): The average glenoid version was significantly different between two measurement techniques for all three observers, with an average of – 7.29° for BM technique and – 10.43° for FM. Intra-observer reliability was excellent for both methods (ICC: 0.958–0.979 for FM; 0.940–0.970 for BM). Inter-observer reliability was excellent for both methods (FM: ICC= 0.977; BM: ICC= 0.962). The light superiority of the first method was not significant. For group 2 – B2 glenoid (n=63): six different measures of version were taken resulting by two scapula reference line (FM and BM) and three glenoid reference line (PG, IG, NG). The average glenoid versions were significantly different (p0.82). The inter-observer reliability were also very-good or excellent for all methods (ICC > 0.79). The most reliable method for measurement of B2 glenoid version was the association of the Friedman line for the scapula axis and the intermediate glenoid line with excellent intra observer reliability (ICC > 0.957) and inter-observer reliability (ICC=0.954).

Conclusion: Measurement of glenoid version on axial cut of a Ct-scan is highly reliable. Significant differences exist between measures depending which method is used, underlying the importance of a consensus for research and clinical purpose. Despite very good performance of all methods, authors recommend the use of the Friedman method for the scapula axis reference and an intermediate glenoid line in case of B2 glenoid.

Purpose: The glenoid status is a crucial aspect of planning for shoulder replacements. This study revisits the classification proposed by Walch et al and discusses its value to orthopedic surgeons in terms of reproducibility and reliability.

Method: Three evaluators viewed one hundred-sixteen (116) shoulder CT-scans with primary glenohumeral arthritis and classified glenoid wear according to Walch classification two times. The validation study was done for three sets of data: Set I: the complete classification: A1, A2, B1, B2, C. Set II: regrouping with main categories: A,B,C. Set III: regrouping categories according to glenoid facet morphology; Normal concavity: A1, A2, B1; Biconcave glenoid: B2; Retroverted glenoid: C.

Results: Intra-observer Kappa values for Observer 1, 2, and 3 averaged 0.866 (0.899, 0.927, 0.773) for Set I; for Set II, the values averaged 0.915 (0.955, 0.975, 0.814); and for Set III, the values averaged 0.874 (0.897, 0.948, 0.777), all excellent values. Inter-observer reliability values for Set I averaged 0.621 (0.776, 0.512, 0.574), indicating good agreement; for Set II, the values averaged 0.759 (0.880, 0.713, 0.685), indicating excellent inter-observer agreement; and for Set III, the average was 0.642 (0.825, 0.519, 0.581), indicating good inter-observer agreement.

Conclusion: A clarification of the Walch et al classification of the osteoarthritic glenoid was necessary, especially with regards to the wordings of categories B2 and C. When used properly, it is a reliable and valuable tool for orthopedic surgeons of all levels of experience in the evaluation of the osteoarthritic glenohumeral joint.