Consistency of Ao Fracture Classification for the Distal Radius

Abstract

W e sought to quantify agreement by different assessors of the AO classification for distal fractures of the radius. Thirty radiographs of acute distal radial fractures were evaluated by 36 assessors of varying clinical experience. Our findings suggest that AO 'type' and the presence or absence of articular displacement are measured with high consistency when classification of distal radial fractures is undertaken by experienced observers. Assessors at all experience levels had difficulty agreeing on AO 'group' and especially AO 'subgroup'. To categorise distal radial fractures according to joint displacement and AO type is simple and reproducible. Our study examined only whether distal radial fractures could be consistently classified according to the AO system. Validation of the classification as a predictor of outcome will require a prospective clinical study.

Are distal radius fracture classifications reproducible? Intra and interobserver agreement

“…In the literature, we saw that κ ranged from 0.37 to 0.60 in different studies, 10,12,16,22 thus suggesting that the intraobserver reproducibility of AO/ASIF should be close to 0.5. In the present study, the mean κ was 0.48, with a range from 0.31 to 0.63.…”

“…In the literature, 10,12,16,22 we saw that the interobserver κ ranged from 0.3 to 0.5. This suggests that the AO/ASIF kappa is close to 0.4, implying unsatisfactory reproducibility.…”

“…This could be explained by the presence of radiologist and orthopedist observers who were working in similar fields and frequently applied the AO/ASIF classification, in the same way as in our study. In the other studies, 12,16,22 expertise played a modifying role in relation to intraobserver reproducibility.…”

“…Studies have shown that less experienced observers attain lower rates of intraobserver agreement than do expert physicians. 12,16 However, in a comparison of one group in which the observers were more experienced in rating assessments with another group whose expertise was lower, no significant difference in interobserver agreement was found. 12 It would also be expected that, as observers study and become accustomed to using a given rating system, the agreement between them, and within their own observations, would increase.…”

“…It is one of the most complete ratings available, but its intra and interobserver reproducibility has been a problem when evaluating groups and subgroups. 11,12 The Universal rating system described by Cooney 13 is characterized by simplicity, classifying fractures as intra or extra-articular, displacement present or absent, and according to the degree of stability and possibilities of reduction. It thus acts as a guide for treatment patterns.…”