Radiographs are not useful in detecting arthroscopically confirmed mild chondral damage

Preoperatively predicting chondral damage is important. Weightbearing radiographs, including the standing antero- posterior and 45° flexion posteroanterior views traditionally have been used for this purpose. We wanted to determine if one radiograph had superior sensitivity or specificity in detecting arthroscopically confirmed Grade II chondromalacia (mild arthritis). A standard prospective standing radio- graphic protocol was designed for all patients who presented to a sports medicine center with knee complaints. Patients who had subsequent arthroscopic surgery had their radio- graphs measured in a blinded manner for articular cartilage intervals in millimeters to detect joint-space narrowing. Intraarticular chondral damage was correlated with the radio- graphic findings. Three hundred forty-nine of a possible 411 (87%) patients during a 2-year period had both radiographs and subsequent arthroscopic grading of chondromalacia. This has been the largest study that correlated arthroscopic chondromalacia grades with two commonly preferred weightbearing radiograph projections. Despite specificities greater than 90%, the sensitivity was extremely low and neither standing radiograph was superior. Neither radiograph was useful in detecting Grade II chondral damage.