TY - JOUR

T1 - Interrater and intrarater reliability of four different classification methods for evaluating acromial morphology on standardized radiographs

AU - Mayntzhusen, Thomas W.

AU - Witten, Adam

AU - Gramkow, Jens

AU - Hansen, Sanja B.

AU - Chatterjee, Shefali A.

AU - Hölmich, Per

AU - Barfod, Kristoffer W.

N1 - Publisher Copyright: © 2023 The Author(s)

PY - 2023

Y1 - 2023

N2 - Background: Acromial morphology is an important pathophysiological factor for the development of subacromial impingement syndrome. There are 3 radiological methods to evaluate acromial morphology: Bigliani, modified Epstein, and acromial angle. However, their reliability have not been compared in a single study, nor using standardized radiographs. Consequently, the evaluation of acromial morphology is currently not validated though its widespread use across the world. The objective of this study was to investigate reliability of the 3 known classifications and the novel Copenhagen Acromial Curve classification. Methods: Three experienced clinicians rated 102 standardized supraspinatus outlet view radiographs with the 4 classification methods in 2 separate sessions a month apart. All measurements were blinded. With an expected kappa (κ) and intraclass correlation coefficient (ICC) > 0.7 (+/−0.15), the target sample size was 87 radiographs. Results: The Bigliani classification had interrater and intrarater reliability ranging from fair to good (κ 0.32-0.41 and 0.26-0.62). The modified Epstein classification had fair to good interrater and intrarater reliability (κ 0.24-0.69 and 0.57-0.63). The acromial angle classification had moderate to good interrater and intrarater reliability (κ 0.53-0.60 and 0.59-0.72). The novel Copenhagen Acromial Curve classification showed moderate to good interrater and intrarater reliability (ICC 0.66-0.71 and 0.75-0.78, respectively). Conclusion: The Copenhagen Acromial Curve was the only classification method with an ICC value > 0.7. The popular Bigliani classification had the worst reliability. The Copenhagen Acromial Curve classification produces numerical data, as opposed to the other 3 classification methods. This could potentially be utilized in future research to establishing cut-off values for treatment stratification.

AB - Background: Acromial morphology is an important pathophysiological factor for the development of subacromial impingement syndrome. There are 3 radiological methods to evaluate acromial morphology: Bigliani, modified Epstein, and acromial angle. However, their reliability have not been compared in a single study, nor using standardized radiographs. Consequently, the evaluation of acromial morphology is currently not validated though its widespread use across the world. The objective of this study was to investigate reliability of the 3 known classifications and the novel Copenhagen Acromial Curve classification. Methods: Three experienced clinicians rated 102 standardized supraspinatus outlet view radiographs with the 4 classification methods in 2 separate sessions a month apart. All measurements were blinded. With an expected kappa (κ) and intraclass correlation coefficient (ICC) > 0.7 (+/−0.15), the target sample size was 87 radiographs. Results: The Bigliani classification had interrater and intrarater reliability ranging from fair to good (κ 0.32-0.41 and 0.26-0.62). The modified Epstein classification had fair to good interrater and intrarater reliability (κ 0.24-0.69 and 0.57-0.63). The acromial angle classification had moderate to good interrater and intrarater reliability (κ 0.53-0.60 and 0.59-0.72). The novel Copenhagen Acromial Curve classification showed moderate to good interrater and intrarater reliability (ICC 0.66-0.71 and 0.75-0.78, respectively). Conclusion: The Copenhagen Acromial Curve was the only classification method with an ICC value > 0.7. The popular Bigliani classification had the worst reliability. The Copenhagen Acromial Curve classification produces numerical data, as opposed to the other 3 classification methods. This could potentially be utilized in future research to establishing cut-off values for treatment stratification.

KW - Acromion

KW - Basic Science Study

KW - Classification

KW - Interrater

KW - Intrarater

KW - Morphology

KW - Reliability

KW - Supraspinatus outlet view

KW - Validation of Classification System

U2 - 10.1016/j.jseint.2023.02.004

DO - 10.1016/j.jseint.2023.02.004

M3 - Journal article

C2 - 37266167

AN - SCOPUS:85151515986

VL - 7

SP - 445

EP - 449

JO - JSES International

JF - JSES International

SN - 2666-6383

IS - 3

ER -