A prospective study of the diagnostic potential of the knee tunnel view radiograph in assessing anterior knee pain. 
The aim of this comparative study was to examine the potential advantage of the tunnel view radiograph over a series of weight bearing antero-posterior (AP), lateral and skyline radiographs.  The study population consisted of 240 subjects with knee pain aged 19 to 93 years.  A total of 309 knees had a weight bearing AP in extension, lateral, skyline and tunnel view radiographs.  Each radiograph was reported with respect to features related to osteoarthritis, modified from the Ahlback system.  Each feature was assessed using the tunnel radiograph alone and then the AP, lateral and skyline views in combination without, and blind to, the information from the tunnel view.  On the basis of Bowker's test, the tunnel view was more likely to pick up abnormal intercondylar notch and tibial spine osteophytes but not loose bodies.  We conclude that the tunnel view is a valuable addition in the routine assessment of the knee joint in osteoarthritis but not for the diagnosis of loose bodies alone.