Goals. Assessment of the clinical value modern MRI in acute intraarticular injuries of the knee. Evaluation the importance of MRI in the diagnosis intraosseous changes in spongy areas micro-fractures form of bone formations that formed the knee joint. Methods. In the period from 2003 to 2006 based on the State Medical Center №1, Ministry of Health of the Russian Federation, RMSC named after Pirogue N.I., orthopedics departments, 221 patients with acute anterior cruciate ligament injury and chronic knee joint instability were operated.The patients were divided by gender: women — 67 (30.4%), men were 154 patients (69.6%). The age of patients ranged from 15 to 57 years (the average age was 29.3 years). Acute knee injury among 211 patients was noted in 86 patients (40.7%), chronic and recurrent instability of the knee joint was noted in 125 patients (59.3%). The mechanism of knee injury was associated with flexion+rotation+valgus/varus abduction. Clinical and special examination of patients was carried out according to standard methods. Results. 100% of the direction on MRI of 211 patients with knee joint pathology diagnosis, before surgery, allowed to increase the level of diagnosis of acute knee injury to 76.6%, and in the chronic stage this percentage was reduced to 100. Thus, in the clinic we were able to improve the quality preoperative diagnosis of knee joint damage and, first of all, damage to the anterior cruciate ligament, especially in the acute period of trauma. In addition, beyond clinical examination after surgery, we used an MRI after surgical treatment to further objectify the results of the anterior cruciate ligament autoplasty. Conclusion. Data of qualitative MRI were previously inaccessible to clinicians, which led patients to a prolonged pain syndrome in the knee joint, formed of arthrogenic contractures, etc. Especially, these MRI data are important, in the case of the alleged completion of the ACL reconstruction operation. In our opinion, if the surgeon does not know about the condyles concussion presence of the femur and tibia, he couldn’t explain the negative clinical picture of the operated patients in the nearest postoperative period. Thus, we believe, without detracting the need for a full-fledged clinical examination, that MRI should become in our country a standard study of pathology not only of the knee, but of any other joint, both in the chronic stage and especially in acute situations. In addition, MRI diagnostics is extremely useful for postoperative follow-up of ACL transplant, provided that absorbable fixing implants are used.