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 < .05, and an inter-rater reliability was calculated using intraclass correlation coefficients.

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 ( = .98). There were no differences in glenoid bone loss calculations between orthopedic surgeons and radiologists or between orthopedic surgeons at critical bone loss values. The interclass correlation coefficient was 0.86 between raters.

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.