Evaluation of magnetic resonance imaging in the intracapsular fracture of femur after internal fixation

MRI was carried out twice or three times for one year in the 24 cases who had received internal fixation for intracapsular fracture of femur. The appearance time of abnormal MRI image, type classification and predicted prognosis were evaluated. Abnormality in MRI was found in 11 cases (46%) and appearance rate was as follows; stage 1: 1/9 (11%), stage 2: 0/3 (0%), stage 3: 4/6 (67%), stage 4: 6/6 (100%). Abnormality was confirmed by high probability in stage 3 and 4. Seven cases whose late segmental collapse (LSC) became clear with X-ray image were classified in stage 3 or 4. Abnormality in MRI was recognized in 7/10 by 2 months, and 11/11 (100%) by 6 months. Abnormal group (11 cases) was classified in 3 types, type 1: 1 case (9%); type 2: 6 cases (54.5%); type 3: 3 cases (27.5%). But there was 1 case which wasn't classified in these classes, and classified as type 4. In this case, ring field of low signal level was found in grit instead of belt field of low signal level in the cases of type 1-3. Seven cases that caused LSC belonged to type 2 or 3, and the LSC was found for less than 24 months. (K.H.)