A cadaveric study was undertaken to determine the best radiographic method of diagnosing dislocation of the proximal tibio-fibular (PTFJ) joint. Three pairs of cadaver knees were used, the right side serving as a control in each case. Plain radiographs, antero-posterior (AP) lateral and 45 degrees oblique films, and axial computed tomography (CT) scans were obtained with the joints in each of three positions: (1) anatomical, (2) dislocated anteriorly and (3) dislocated posteriorly. Similar views were obtained in the control joints with the PTFJ undisturbed. The radiographs were assessed by eight independent observers and the results were analysed. The diagnostic accuracy with plain AP and lateral radiographs was 72.5%. This was unchanged with the addition of oblique views, but improved to 82% with the control films and 86% with the axial CT scans. The authors conclude that in the diagnosis of suspected dislocation of the PTFJ, axial CT scanning is the investigation of choice. Plain AP, lateral and comparison views are useful but less accurate, while oblique views are unhelpful and unnecessary.