Detecting radiographic knee osteoarthritis: what combination of views is optimal?

Objective. The failure to image the patellofemoral joint or the posterior k nee compartment when evaluating persons for knee osteoarthritis may result in missed cases. While the skyline view has been recommended due to more re producible assessment of the patellofemoral joint space, the lateral view m ay be easier to acquire and provides different information. We evaluated th e sensitivity of different combinations of X-ray views (anteroposterior and lateral; anteroposterior and skyline; all three views) in 377 persons with knee symptoms who had all three views available and had a definite osteoph yte on at least one view. Results. Of the different views, skylines had to be excluded most often bec ause the image of the patellofemoral joint was technically unsatisfactory. In the remaining knees, adding either a lateral or a skyline view to an ant eroposterior view yielded roughly equal and high sensitivity (94-97%) when compared with the gold standard of a positive X-ray on any of the three vie ws. Conclusion. As long as at least an anteroposterior view and one image of th e patellofemoral joint is obtained (either skyline or lateral), few cases w ith radiographic disease will be missed. For clinical or epidemiological st udies the lateral view may be easier to acquire with high quality than the skyline view.