36 Acta Orthop Scand 2001; 72 (1): 36–41 ABSTRACT – 20 radiographs of pertrochanteric femoral fractures were classified as to fracture “group” and “sub- group” according to the AO/ASIF Fracture Classification (type 31A) by 15 observers. 3 months later, the same ra- diographs were reviewed by the same observers. Mean agreement of the observers with the final consensus ranged from 53% (with subgroup classification) to 81% (without subgroup). The mean kappa value for interob- server reliability was 0.33 and 0.34 for classification with subgroup in both observer sessions, respectively. Omis- sion of the subgroup classification resulted in better mean kappa values (0.67 and 0.63, respectively). Mean intra- observer reliability was 0.48 in the fracture “subgroup” and 0.78 in the “group” classification. In conclusion, the results show that the AO/ASIF clas- sification for pertrochanteric fractures is reliable for fracture subgroups 31A1, A2 or A3. The group classifi- cation should be used to compare scientific data and de- termine the best treatment. Further classification of fracture subgroups leads to poor reproducibility of re- sults. n Reliability of the AO/ASIF classification for pertrochanteric femoral fractures Inger B Schipper 1,3 , Ewout W Steyerberg 2 , Rene M Castelein 1 and Arie B van Vugt 3 1 Isala Clinics, Weezenlanden Hospital, Departments of General and Orthopedic Surgery, Zwolle, The Netherlands, 2 Erasmus University Rotterdam, Department of Public Health, Rotterdam, The Netherlands, 3 University Hospital Rotterdam Dijkzigt, Department of Traumatology, Rotterdam, The Netherlands. Correspondence: Dr. I.B. Schipper, Department of Traumatology, University Hospital Rotterdam, Dr. Molewaterplein 40, NL-3015 GD Rotterdam, The Netherlands. Tel +31 10 4639222. E-mail: ibschip@xs4all.nl Submitted 00-04-30. Accepted 00-08-07 Copyright © Taylor & Francis 2001. ISSN 0001–6470. Printed in Sweden – all rights reserved. Nowadays, the commonest classification is that of Fractures of the Long Bones introduced by the AO/ASIF group (Müller et al. 1990). This classifi- cation is organized into hierarchical triads. For every bone segment (e.g., femur, tibia or humer- us), 3 “types” of possible fractures exist (A, B, C), each of which can be divided into 3 “groups” (e.g., for pertrochanteric fracture groups A1, A2, A3). The 3 groups are each divided into 3 “sub- groups” according to increasing fracture severity, indicating a greater difficulty in operative treat- ment, a higher likelihood of complications, and a poorer prognosis (Figure). Despite its common use and wide acceptance, its reliability and repro- ducibility have been questioned for a small num- ber of specific fracture types (Johnstone et al. 1993, Siebenrock and Gerber 1993, Kreder et al. 1996, Martin et al. 1997, Craig and Dirschl 1998). Systematic classification of a pertrochanteric frac- ture may reduce problems related to interpretation of the fracture and facilitate the choice of the ap- propriate method of treatment. To assess clinical studies on various types of pertrochanteric hip fractures, a reproducible classification is manda- tory. Therefore, we assessed the interobserver and in- traobserver reliability of the AO/ASIF classifi- cation system for pertrochanteric femoral frac- tures. Interobserver reliability was assessed for fracture “group” classification and for “subgroup” classification during 2 radiograph sessions. We also evaluated interobserver reliability among 3 different groups of observers (surgeons, surgical residents and radiologists). Material and methods The preoperative anteroposterior and lateral ra- diographs of 20 patients admitted to our hospital in 1998 with pertrochanteric femoral fractures were selected from a trauma database. No special Acta Orthop Downloaded from informahealthcare.com by 186.192.240.114 on 05/20/14 For personal use only.