Investigation into MRI diagnostic value of occult fracture of knee

Objective To investigate the MRI manifestation of knee joint occult fracture and its clinical value. Methods 35 cases who suffered from obvious pain after knee trauma but were not diagnosed as having fracture by X ray were analyzed and given re examination of MRI. The MRI signals were focused on femur, fibula and patella, anterior and posterior cruciate ligament, media and lateral meniscus. Results All the 35 cases who had been diagnosed as normal by X ray film were found to have occult fractures by MRI. Of the 35 cases, 11 case had CT scanning and 3 were found to have occult fracture. The most frequent sites of occult fracture were medial and lateral condyle of femur (13/35) and tibial plateau (14/35). Conclusion MRI is the best method in the diagnosis of occult fracture of knee joint. For patients with obvious knee joint pain after injury the MR scanning is necessary even when their X ray and /or CT results are normal so that the misdiagnosis and delayed diagnosis can be avoided as much as possible.