OBJECTIVETo investigate the MRI diagnosis of bone contusion on the knee, and improve the diagnosis skill.

METHODSA retrospective analysis of 47 cases of knee bone bruise with the performance of MRI in our hospital from 2008.5 to 2009.12, including 30 males and 17 females,aged from 12 to 69 years, with a mean of 34.5 years old. Forty-seven patients suffered from post-traumatic localized pain, tenderness and(or) soft tissue swelling and dysfunction. The time interval between the accident and the MRI examination ranged from 6 h to 30 days, averaged 7 days. The patients with only bone contusion were treated with conservative and symptomatic treatment.

RESULTSA total of 47 cases showed 82 lesions, including 39 distal femur, 35 proximal tibias (including the tibial plateau),5 patellas, 3 fibula top. MRI showed irregular patchy or map-like T1WI low signal, isointensity or slightly high signal intensity T2WI, STIR fat suppression all showed obviously high signal, in which 20 patients with torn meniscus, collateral ligament injuries in 14 cases, anterior cruciate ligament injuries in 8 cases. The X-ray and CT examination of all the patients revealed no signs of fracture. The clinical symptoms and signs of all the patients significantly reduced or disappeared after treatment. Among 29 patients who were followed up from 1 to 12 months, 21 patients had abnormal MRI signal disappearing and 8 patients had abnormal signal weakened.

CONCLUSIONMRI can reveal pathological changes of bone contusion on the knee, and accurately determine ligaments around the joint and soft tissues injuries. Conventional MRI examination and fat-suppression sequence is the most valuable method of bone contusion.