Are lateral view radiographs necessary to properly classify femoral neck fractures? Intra and interobserver analysis using Garden's classification system

INTRODUCTION Femoral neck fractures have been historically diagnosed by anteroposterior (AP) and lateral (L) radiographic views. We analyzed the importance of the L view for management of femoral neck fractures, using the Garden's classification system. MATERIALS AND METHODS Slides were elaborated with AP and L radiographic views of 100 patients with femoral neck fractures admitted to our emergency department. Three hip surgeons assessed independently AP views only and then AP and L views together using Garden's classification system. RESULTS No statistically significant differences (Kruskal Wallis 0, p=1) were found while comparing categories among Garden's classification system, after assessing L views. There was an 81 % (p < 0.001) agreement of Garden category between AP and AP combined with L views. When analyzing patients with changing categories between displaced and non displaced after assessing L view images, we found a 5% (n=5, CI 95% 1-11%) of change. For comparing AP Garden with L view Garden, we used a quadratic weighted kappa method. CONCLUSIONS There is a high agreement in the Garden category when comparing AP with combined AP and L observations. Five patients would have received a different surgical treatment dependent on the hip surgeon who assessed the radiographs. This highlights the relevance of routinely L radiographs whenever a femoral neck fracture is suspected.