Reliability and reproducibility of the new AO/OTA 2018 classification system for proximal humeral fractures: a comparison of three different classification systems

Abstract

Background: The classification systems for proximal humeral fractures routinely used in clinical practice include the Neer and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 2007 systems. Currently used systems have low inter-and intraobserver reliability. In 2018, AO/OTA introduced a new classification system with the aim of simplifying the coding process, in which the Neer four-part classification was integrated into the fracture description. The aim of the present work is to assess the inter-and intraobserver agreement of the new AO/OTA 2018 compared with the Neer and AO/OTA 2007 classifications. Materials and methods: A total of 116 radiographs of consecutive patients with proximal humeral fracture were selected and classified by three observers with different levels of experience. All three observers independently reviewed and classified the images according to the Neer, AO/OTA 2007, and new AO/OTA 2018 systems. To determine the intraobserver agreement, the observers reviewed the same set of radiographs after an interval of 8 weeks. The inter-and intraobserver agreement were determined through Cohen's kappa coefficient analysis. Results: The new AO/OTA 2018 classification showed substantial mean inter-(k = 0.67) and intraobserver (k = 0.75) agreement. These results are similar to the reliability observed for the Neer classification (interobserver, k = 0.67; intraobserver, k = 0.85) but better than those found for the AO/OTA 2007 system, which showed only moderate inter-(k = 0.57) and intraobserver (k = 0.58) agreement. The two more experienced observers showed better overall agreement, but no statistically significant difference was found. No differences were found between surgical experience and agreement regarding specific fracture types or groups. Conclusions: The results showed that the Neer system still represents the more reliable and reproducible classification. However, the new AO/OTA 2018 classification improved the agreement among observers compared with the AO/OTA 2007 system, while still maintaining substantial descriptive power and simplifying the coding process. The universal modifiers and qualifications, despite their possible complexity, allowed a more comprehensive fracture definition without negatively affecting the reliability or reproducibility of the classification system.

Poor reliability and reproducibility of 3 different radiographical classification systems for distal ulna fractures

“…When assessing the reliability and reproducibility of the AO/OTA 2018 classification compared with the previous AO/OTA 2007 and Neers classification for proximal humeral fractures a substantial mean inter- and intra-rater agreement was seen for the AO/OTA 2018 system. The interrater agreement was substantially higher for the AO/OTA 2018 compared with the AO/OTA 2007 classification ( 12 ).…”

What is the interobserver agreement of displaced humeral surgical neck fracture patterns?

“…The interobserver reliability of the general AO and full Neer classification systems has been studied intensively. However, many of these studies had a limited number of observers, which could result in overestimation of agreement, and the question remained unanswered as to the interobserver agreement for the subgroups of surgical neck fractures (Neer included three subgroups, and AO included two subgroups) [ 14 , 15 ]. Regarding the AO classification, the largest study included 46 observers and found a kappa of 0.18 [ 10 ].…”

Not All Proximal Humerus Fractures Do Well Without Surgery: Anterior Translation Predicts the Need for Surgery

“…A retrospective review of Current Procedural Terminology (CPT) codes, trauma registries, and operative logs between 2005 and 2015 was conducted at 5 trauma centers to identify patients who sustained isolated low-energy proximal humerus fractures (OTA/AO 11 A-C) initially treated nonoperatively. 16,17 To be included, patients needed to be skeletally mature and have an isolated low-energy proximal humerus fracture. Skeletally immature individuals, patients with pathologic fractures, patients who were nonambulatory before their injury, and those unable to follow-up at least 84 days were excluded from review and analysis.…”