O2295 HALLUX VALGUS–TREATMENT ALGORITHM: IS THE RADIOGRAPHIC ASSESSMENT RELIABLE?

Abstract

Aims: To assess the reliability and repeatability of the þve described methods of measuring hallux valgus (HVA) and intermetatarsal angles (IMA). The diagnosis of congruency of þrst MTP joint was also assessed. Methods: Five Orthopaedic staff analysed 50 pre-operative standing foot radiographs on two occasions. ANOVA was used to examine the difference between the þve methods and between the þve observers, for both IMA and HVA. Kappa test was used to measure agreement in diagnosing congruency between two occasions. Results: The mean IMA and HVA varied signiþcantly between some of the methods (p< 0.00001). The ANOVA model showed that both method and observer variations (p=0.0264 and p< 0.001 respectively) were signiþcant for IMA and there was no signiþcant difference between measurement methods (p=0.7882) for HVA. The intraobserver reliability of congruency was good (k=0.608) but the interobserver reliability was only fair (k=0.261). A second IMA measurement will lie between 4.2û less and 4.6û more than the þrst IMA measurement 95% of the time. A second HVA measurement will lie between 6û less and 5.6û more than the þrst HVA measurement 95% of the time. Conclusions: This study shows that the different methods give signiþcantly different results. The methods are, therefore, not interchangeable. There was no advantage to any of the method in terms of reliability. All methods had considerable inter- and intra- observer variability that makes these measurements unreliable.