ASSESSMENT OF THE AO ASIF FRACTURE CLASSIFICATION FOR THE DISTAL TIBIA/

Objectives: The purpose of this study was to assess the interobserver reliability and intraobserver reproducibility of the AO/ASIF and Ruedi and Allgower classifications for fractures of the distal tibia, and t o determine the benefit of a computed tomography (CT) scan and experie nce on observer agreement for several fracture characteristics, includ ing classification. Methods: The radiographs of forty-three fractures of the distal tibia, fourteen of which had CT scans, were assessed by groups of experienced and less-experienced observers. Each case was cl assified according to the AO/ASIF and Ruedi and Allgower systems. Seve ral other fracture characteristics also were assessed. The kappa coeff icient of agreement was calculated and used to compare the interobserv er reliability and intraobserver reproducibility of the classification systems and to determine the benefit of experience and CT scans. The intraclass correlation coefficient was used to assess noncategoric dat a. Results: Interobserver and intraobserver agreements were good when classifying fractures into AO/ASIF types and significantly better than that for the Ruedi and Allgower system. However, agreement was poor w hen classifying the fractures into AO/ASIF groups. For most assessment s, the experienced group tended to have higher levels of interobserver agreement, but not intraobserver agreement. Viewing the CT scans impr oved agreement on the percentage of articular surface involved, but it did not improve interobserver reliability or intraobserver reproducib ility for either of the classification systems. Conclusion: The AO/ASI F classification for fractures of the distal tibia has good observer a greement at the type level, but poor agreement at the group level. Exp erience tends to improve interobserver agreement, but not intraobserve r agreement. Viewing CT scans does not improve agreement on classifica tion, but it tends to improve agreement on articular surface involveme nt.