Diagnosis of medial tubercle fractures of the talar posterior process using oblique views.

Fracture of the medial tubercle of posterior process of talus is a very rare injury. Often, these fractures are not seen on the AP and lateral radiographs of the ankle joint resulting in them being misdiagnosed as an ankle sprain. This study examines 10 ankle specimens simulated with a posteromedial fracture in varying planes, by multiple X-ray views in varying angles of external rotation in order to increase the sensitivity of oblique views to diagnose a fracture of the posteromedial tubercle. True AP and lateral views (0 degrees and 90 degrees of external rotation) of the ankle joint were unable to detect the fracture simulated in the posteromedial tubercle of the posterior process in any specimens. The fractures in all the specimens were clearly visible when the X-ray beam was parallel to the plane of osteotomy. The fractures could still be identified when the plane of X-ray beam was within +/-10 degrees from the plane of osteotomy. Any further increase or decrease in plane of the X-ray beam could not identify the fracture. Two oblique views at 45 degrees and 70 degrees of external rotation could identify the fractures of the posteromedial tubercle at all planes. These oblique views can be used before resorting to the CT scan.