Computed tomography-based classifications of posterior malleolar fractures and their inter- and intraobserver reliability: a comparison of the Haraguchi, Bartoníček/Rammelt, and Mason classifications

INTRODUCTION: Complex ankle fractures often include fractures of the posterior malleolus. The most clinically relevant posterior malleolus fracture classifications are computed tomography (CT) based. These classifications aim to enable clear communication and help develop treatment strategies. This study investigates the inter- and intraobserver reliability of the Haraguchi, Bartoníček/Rammelt and Mason posterior malleolar fracture classifications.

MATERIALS AND METHODS: CT scans of 113 patients with a mean age of 56.2 (SD ± 17.8) years and fractures involving the posterior malleolus were analyzed twice by 4 observers with different levels of training. The posterior malleolar fractures were classified according to Haraguchi et al., Bartoníček/Rammelt et al. and Mason et al. The intraobserver and interobserver reliabilities were determined by calculating Cohen's and Fleiss' kappa values.

RESULTS: We found substantial multi-rater interobserver agreement for all three classifications. The Haraguchi classification 0.799 (CI 0.744-0.855) showed the highest agreement, followed by the Bartoníček/Rammelt 0.744 (0.695-0.793) and Mason 0.717 (CI 0.666-0.768) classifications. Subgroup analyses showed substantial to perfect agreement for the Haraguchi and substantial agreement for the Bartoníček/Rammelt and Mason classifications independent of observer expertise. The intraobserver reliability was perfect for three and substantial for one of the observers. However, the classifications have certain pitfalls and do not consider the number of fragments, articular surface impressions, or intercalary fragments.

CONCLUSION: All classifications show substantial, if not perfect inter- and intraobserver reliabilities independent of observer level of expertise.