The Combination of the Tunnel View and Weight-Bearing Anteroposterior Radiographs Improves the Detection of Knee Arthritis

Imaging used for the evaluation of knee pain has historically included weight-bearing anteroposterior (AP), lateral, and sunrise radiographs. We wished to evaluate the utility of adding the weight-bearing (WB) posteroanterior (PA) view of the knee in flexion. We hypothesize that (1) the WB tunnel view can detect radiographic osteoarthritis (OA) not visualized on the WB AP, (2) the combination of the AP and tunnel view increases the radiographic detection of OA, and (3) this may provide additional information to the clinician evaluating knee pain. We retrospectively reviewed the WB AP and tunnel view radiographs of 100 knees (74 patients) presenting with knee pain and analyzed for evidence of arthritis. The combination of the WB tunnel view and WB AP significantly increased the detection of joint space narrowing in the lateral (p < 0.001) and medial (p = 0.006) compartments over the AP view alone. The combined views significantly improved the identification of medial subchondral cysts (p = 0.022), sclerosis of the lateral tibial plateau (p = 0.041), and moderate-to-large osteophytes in the medial compartment (p = 0.012), intercondylar notch (p < 0.001), and tibial spine (p < 0.001). The WB tunnel view is an effective tool to provide additional information on affected compartments in the painful knee, not provided by the AP image alone.