3D-radiographic analysis does not improve the Neer and AO classifications of proximal humeral fractures

Abstract

The Neer and AO fracture classifications for fractures of the proximal humerus have shown poor reproducibility based on plain radiography. We wanted to investigate whether the addition of 3-dimensional (3D) reconstructions would increase the reproducibility of classification. 7 observers independently classified 24 fractures of the proximal humerus using both plain radiographs, CT and 3D and the classification was repeated 2 months later. There was a moderate interobserver agreement when using the Neer classification, but only a fair agreement with the AO classification. The Neer system had a mean kappa value of 0.44 and the AO had a value of 0.32 for the first assessment. In the second assessment, the mean kappa values were 0.49 and 0.34, respectively. Intraobserver reproducibility was fair to substantial agreement for Neer (kappa range 0.27-0.73) and for AO (kappa range 0.29-0.74). In conclusion, the addition of CT and 3D to plain radiographs did not improve the reproducibility of the classifications of Neer and AO of the proximal humerus.

Low agreement among 24 doctors using the Neer-classification; only moderate agreement on displacement, even between specialists

“…Bernstein et al [2] reported a mean kappa value of 0.52. No significant improvement of mean kappa values has been demonstrated despite exclusive use of high-quality radiographs [2,13] or by adding CT scans and three-dimensional reconstructions [2,12,15,16].…”

“…1) of proximal humeral fractures is commonly used. Several previous studies have shown poor agreement between observers using the system [1,2,3,9,12,13,14,15,16]. Low agreement might explain conflicting study outcomes of the treatment of three-and four-part fractures [4].…”

“…Prior to calculations the original 16 Neer groups were reduced to six groups (Table 1). Mean kappa values for all pairs of observers were calculated, and a pre-defined subgroup analysis of agreement within three levels of clinical experience was performed.…”

Proximal humeral fractures

“…[26][27][28][29][30] Because important new concepts for prognosis and treatment of PHF do not easily fit in past classification systems, some authors have proposed new imaging techniques 8,12 or new functional classifications. 14 Since 2003, new systems of fracture classifications have been published. 20,22,31,32 Hertel 22 presented a structured system for reading images, including 12 questions, which require 3-D image measurements.…”

Reproducibility of three classifications of proximal humeral fractures

“…Such difference towards classifications' agreement could be due to multiple variables, for example, studies of low quality because of difficulties in placing patients with a fracture of proximal humerus, and also the surgeon's lack of experience to analyze these fractures (5)(6)(7)(8)(9)(10) . In spite of improvements demonstrated by some authors in the agreement of intra-and interobserver results using more complex tests like simple tomography and tridimensional (3D) reconstructions, these results are inconclusive when the relationship between classifications and suggestions of treatment is evaluated towards physician's experience (7)(8)(9) .…”