Inter-rater reliability in calculating glenoid bone loss among orthopedic surgeons and musculoskeletal radiologists: how much do we agree?

Background: In shoulder instability, preoperatively quantifying the amount of glenoid bone loss is performed by both orthopedic surgeons and musculoskeletal radiologists and is crucial in guiding ultimate management. While there exists a high inter-rater reliability when using 3-dimensional (3D) computed tomography (CT) reconstruction to evaluate glenoid bone loss among orthopedic surgeons, no studies have examined the inter-rater reliability of glenoid bone loss measurements between radiologists and orthopedic surgeons. The aim of this study is to determine if a difference exists in glenoid bone loss interpretation on 3D CT reconstruction between these specialties. Methods: A retrospective review of patients with a 3D CT scan of the shoulder performed at a single institution with a glenoid bone loss calculation by an attending musculoskeletal radiologist was identified. Two orthopedic surgeons independently calculated the percentage of glenoid bone loss using the best-fit circle technique. Glenoid bone loss measurements between the radiologists and orthopedic surgeons were compared with a significance of Results: A total of 95 patients with an average age of 35.9 years and primarily anterior (n = 75; 78.9%) glenoid bone loss were included. The average glenoid bone loss calculated by attending radiologists and orthopedic surgeons was 20.3 ± 11.3 and 20.2 ± 9.8, respectively ( Conclusion: There are no significant differences in the calculation of glenoid bone loss among orthopedic surgeons and radiologists and a high overall inter-rater reliability between the specialties. These findings highlight the reproducibility of the best-fit circle technique when applied to 3D CT imaging among specialties, emphasizing that orthopedic surgeons can consult and trust radiology reports when developing their treatment plan for shoulder instability.