Classification of proximal humeral fractures based on a pathomorphologic analysis.

BACKGROUND: The purpose of this study was to analyze the pathomorphology of proximal humeral fractures to determine relevant and reliable parameters for fracture classification. METHODS: A total of 100 consecutive acute proximal humeral fractures in adult patients were analyzed by 2 non-independent observers from a single shoulder department using a standardized protocol based on biplane radiographs and 3-dimensional computed tomography scans. A fracture classification system based on the most reliable key features of the pathomorphologic analysis was created, and its reliability was tested by 6 independent shoulder experts analyzing another 100 consecutive proximal humeral fractures. RESULTS: The head position in relation to the shaft (varus, valgus, sagittal deformity) and the presence of tuberosity fractures showed a higher interobserver reliability (κ > 0.8) than measurements for medial hinge, shaft, and tuberosity displacement, metaphyseal extension, fracture impaction, as well as head-split component identification (κ < 0.7). These findings were used to classify nondisplaced proximal humeral fractures as type 1, fractures with normal coronal head position but sagittal deformity as type 2, valgus fractures as type 3, varus fractures as type 4, and fracture dislocations as type 5. The fracture type was further combined with the fractured main fragments (G for greater tuberosity, L for lesser). Interobserver and intraobserver reliability analysis for the fracture classification revealed a κ value (95% confidence interval) of 0.700 (0.631-0.767) and 0.917 (0.879-0.943), respectively. CONCLUSION: The new classification system with emphasis on the qualitative aspects of proximal humeral fractures showed high reliability when based on a standardized imaging protocol including computed tomography scans.

Proximal humeral fracture classification systems revisited.

HYPOTHESIS: This study evaluated several classification systems and expert surgeons' anatomic understanding of these complex injuries based on a consecutive series of patients. We hypothesized that current proximal humeral fracture classification systems, regardless of imaging methods, are not sufficiently reliable to aid clinical management of these injuries. MATERIALS AND METHODS: Complex fractures in 96 consecutive patients were investigated by generation of rapid sequence prototyping models from computed tomography Digital Imaging and Communications in Medicine (DICOM) imaging data. Four independent senior observers were asked to classify each model using 4 classification systems: Neer, AO, Codman-Hertel, and a prototype classification system by Resch. Interobserver and intraobserver κ coefficient values were calculated for the overall classification system and for selected classification items. RESULTS: The κ coefficient values for the interobserver reliability were 0.33 for Neer, 0.11 for AO, 0.44 for Codman-Hertel, and 0.15 for Resch. Interobserver reliability κ coefficient values were 0.32 for the number of fragments and 0.30 for the anatomic segment involved using the Neer system, 0.30 for the AO type (A, B, C), and 0.53, 0.48, and 0.08 for the Resch impaction/distraction, varus/valgus and flexion/extension subgroups, respectively. Three-part fractures showed low reliability for the Neer and AO systems. DISCUSSION: Currently available evidence suggests fracture classifications in use have poor intra- and inter-observer reliability despite the modality of imaging used thus making treating these injuries difficult as weak as affecting scientific research as well. This study was undertaken to evaluate the reliability of several systems using rapid sequence prototype models. CONCLUSION: Overall interobserver κ values represented slight to moderate agreement. The most reliable interobserver scores were found with the Codman-Hertel classification, followed by elements of Resch's trial system. The AO system had the lowest values. The higher interobserver reliability values for the Codman-Hertel system showed that is the only comprehensive fracture description studied, whereas the novel classification by Resch showed clear definition in respect to varus/valgus and impaction/distraction angulation.