Comparative Research Of Osteonecrosis Of The Knee Between MRI And Histopathology

Osteonecrosis is a common orthopedics disease, which is a kind of ischemic death of osteocytes and bone marrow cells induced by circulation obstacle. The incidence of the osteonecrosis of the femoral head is the highest, just a little more than that of the osteonecrosis of the knee. Of all the diseases located in the knee, osteonecrosis is about 2%, which is the critical etiopathogenisis of the osteoarthritis. ONK can be categorized into two groups, spontaneous or secondary. The former one is the type which has no definite reasons while the latter one is on the opposite, such as steroid, alcohol, trauma, SLE and so on. Additionally, rheumatoid arthritis with the treatment of steroid is also considered to be a proved reason. However, there is still no agreement on whether RA without treatment of steroid, can be classified as the primary osteonecrosis or not. Furthermore, degenerative osteoarthritis is also not presumed as the conclusive cause of osteonecrosis. According to all the demonstrations above, we assign 35 patients (35 knees), with degenerative OA, to the primary ON group while assign the 11 patients (13 knees), with RA, to another group alone. Spontaneous osteonecrosis of the knee was reported as a distinct disease by Alhb?ck in 1968, and since then, a great deal of literatures came out. But most of them were focus on the femoral head rather than the knee. Old women, especially fat, is liability to spontaneous osteonecrosis of the knee (SONK). The lesions are limited in the subchondral zone, mostly single and always locate in the medial femoral condyle, still can be seen in the lateral femoral condyle, tibial plateau and patella. The characteristics are severe pain in the jointspace, rest pain(apparently in the midnight),with slight synovitis, effusion and mild restriction of motion. These symptoms and signs are easily to be distinguished from that of secondary osteonecrosis, which is multiple lesions, diffused distribution, slow onset pains, while hard to be differentiated from that of the diseases inside the knee, taking meniscus injury as an example. The prognosis of SONK is dependeded on the prompt diagnosis as early as possible. conservative treatment can manage early lesions while operations, even the articulus reestablishment operations, are unavoidable for the late lesions. It is confirmed that traditional X plain radiograph is not sensitive to the early lesions and the sensitivity and specificity of radioisotope scanning is worse than MRI. Therefore, MRI is generally accepted as a predominant non-invasion way to diagnose osteonecrosis. As patients at various stages need different therapeutic tools, MRI is responsibility to offer a clue to the SONK staging diagnosis. Unfortunately, there is few retrospective studies to describe different appearances of MRI in different stages according to the therapeutic result, not to mention the systematic staging of MRI representation. As a result, we purpose to initially construct systematic staging of MRI based on the observations on MRI appearances in various stages of SONK. We also use corresponding histopathological staging as the evaluation criterion in that there is still some arguments on the diagnosis specificity of MRI. Our reseach is divided into two sections as follows:Initially construct systematic staging of MRI via pathological staging and appearances comparison of corresponding sections.From Feb,2006 to Feb,2007, in the Jointsurgery Center out-patient clinic, Southwest Hospital, TMMU, the patients ,who are suspiciously diagnosised ONK via clinical features and radiological appearances and whose pathological specimen can be obtained by TKA operation are admitted in this research and assigned to the group A. Patients who have definite osteonecrosis etiopathogenisis such as trauma history, conduction of steroid and alcoholism and whose preoperative diagnosis is RA are eliminated. Among these 35 candidates (35 knees), 5 of them are male(5 knees), 30 are female(30 knees), aged from 49 to 79, at an average of 69.0. 21 of the knees are left while 14 are right. All the cases are undergoing pre-operation MRI examination and post-operation pathological biopsy of corresponding sections of the osteoectomy specimen. These data were classified by stages double-blindly according to the MRI and pathological staging protocols by two radiologists and two pathologists. It is shown that there is no significant deviation in the staging outcomes of the two radiologists, which are 3 cases belonging to the 0 stage of MRI; 4 cases, the first; 16 cases, the second and 12 cases, the third. Further more, it is proved that, according to the correlation analysis, all the cases belonging to the 0 stage of MRI are pertaining to the 0 stage of pathology; all the cases belonging to the first stage of MRI are pertaining to the first stage of pathology; of all the cases belonging to the second stage of MRI ,2 cases are the pertaining to the first stage of pathology and 14 cases are the second; of all the cases belonging to the third stage of MRI ,2 cases are the pertaining to the second stage of pathology and 10 cases are the third. It is demonstrated that the MRI staging is of highly concordance with the pathological staging by the preliminary experiment.2. MRI appearance and pathological variation control study of the ONK with RAFrom Feb,2006 to Feb,2007, in the Jointsurgery Center out-patient clinic, Southwest Hospital, TMMU, The patients who are suspiciously diagnosised ONK via clinical features and radiological appearances, whose pathological specimen can be obtained by TKA operation and whose preoperative diagnosis is RA are admitted in this research and assigned to the group B. Patients who have definite osteonecrosis etiopathogenisis such as trauma history, conduction of steroid and alcoholism are eliminated. Among these 11 candidates (13 knees), 3 of them are male(4 knees), 8 are female(9 knees), aged from 51 to 71, at an average of 61.0. 8 of the knees are left while 5 are right. All the cases are also undergoing double-blind evaluation of MRI and pathology. The differences between the SONK are as follows: 10 cases have the similar MRI characteristics to those of the second stage of SONK, of which, 9 cases have the similar pathological characteristics to those of the second stage of SONK and 1 cases ,the third; 2 cases have the similar MRI characteristics to those of the third stage of SONK and all of them have the similar pathological characteristics to those of the third stage of SONK.Through this research, we can draw these conclusions: 1) the mri staging method constructed in this research, to some extent, has objectivity and feasibility. as a result, various radiologists with similar seniority can divide mri apperances of sonk into different stages objectively through this method. 2)MRI staging constructed in this research is of highly concordance with the pathological staging, which can be initially used as a principle of SONK staging diagnosis and therapeutic regimens selection based on the staging. The specific abnormal appearances in various MRI sequences during the different stages of SONK have their own pathological foundation, as different changes of signals can reflect reciprocal pathological diversities; 3) The pathological changes and MRI appearances of ONK accompanied with RA without steroid history are similar to those of SONK and might belong to SONK, whereas distinct to those of steroid-using types. As a result, we can presume that there may be many differences in the pathogenesy.