The Association Of BMLs/OAPC Of The Subchondral Bone With Stabilizer Failure In Knee Joint

Objective: To evaluate the contribution of the stabilizing structures of the knee and other stress factors to the subchondral bone marrow edema-like lesions (BMLs) and osteoarthritis subchondral pseudocyst (OAPC) of the knee, and to further indentify the relationship between stabilizer failure of the subchondral bone and the subchondral focal lesions of the knee.Methods: Three hundred and seven knee MR images were collected between February 2009 and Aprial 2009. The patients aged 7～85 years old, and their mean age is 51.94±13.17 years. They were divided into the stabilizer failure group and the normal structure group. The patients with pain and meniscus tear or extrusion or cartilage defect or ligaments tear were included in the stabilizer failure group. The patients with pain and normal stabilizing structure were included in the normal structure group. There were 281 patients in the stabilizer failure group, including 90 men and 191 women. There were 26 patients in the normal structure group, including 11 men and 15 women.Medical history and symptom were collected including morbility motivation and treatment course, trauma history, heavy activities, hormone therapy history, alcohol abuse history, blood disease, collogen disease and diving history. Age, sex, height, weight were recorded. MR images were graded by WORMS, including the cartilage, the meniscus, the ligaments (the anterior and posterior cruciate ligament, the medial and lateral collateral ligament), bone marrow edema, cyst, joint effusion and osteophytes. The presence of subchondral focal lesions between the stabilizer failure group and the normal structure group were compared and analyzed, as well as the presence of subchondral focal lesions between the cartilage defect and normal, the meniscus tear and normal and the ligaments tear and normal in the stabilizer failure group. The relationship between stabilizing structures and subchondral BMLs and OAPC, the relationship among the stabilizing structures, the relationship between the subchondral BMLs and OAPC and the relationship between the meniscus extrusion and osteophytes were tested by correlative analysis. The difference of the size of the subchondral focal lesions between the BMI normal and overweight of the man and women were all by significant difference analysis. The abnormality of the stabilizing structures and possible risk factors affected the size of subchondral focal lesions were tested by logistic regression method. The stabilizing structures among the groups of the pure BMLs, the pure OAPC and the BMLs and OAPC simultaneously were compared. The stress history of the subchondral BMLs and OAPC of the stabilizer failure group were also analyzed.Results:1 Comparison of the presence of subchondral focal lesions between stabilizer failure group and normal structure group245 subchondral focal lesions were found in the stabilizer failure group, while only 1 lesion with overuse history was found in the normal structure group. Chi-square test showed statistically significant differences between the two groups. There were more subchondral focal lesions in the stabilizer failure group. There were 207 BMLs, 122 OAPC, 11 spontaneous osteonecrosis of the knee (SONK), 3 osteochondritis dissecans (OCD) in the 246 subchondral focal lesions of the knee, but we did not make a detailed study of the SONK and OCD due to small simple size.2 Comparison of the presence of subchondral BMLs and OAPC between the steady structure defect and normal in the stabilize failure groupThe presence of BMLs and OAPC was significant higher in patients with cartilage defect than normal. The presence of medial femoral condyal (MFC) and medial tibial plateau (MT) BMLs was significant higher in patients with meniscus tear or extrusion than normal. The presence of MT BMLs and OAPC was significant higher in patients with the anterior horn of the meniscus extrusion than normal. The presence of MFC BMLs and OAPC, MT BMLs was significant higher in patients with the posterior horn of the medial meniscus extrusion than normal. The presence of lateral tibial plateau (LT) BMLs and OAPC was significant higher in patients with the anterior horn of the lateral meniscus tear than normal. The presence of LT BMLs was significant higher in patients with the posterior horn of the lateral meniscus tear than normal. The presence of LT OAPC was significant higher in patients with the posterior horn of the lateral meniscus extrusion than normal. The presence of subchondral BMLs was significant higher in patients with the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL) and the medial collateral ligament (MCL) tear than normal. The presence of subchondral BMLs and OAPC was significant higher in patients with lateral collateral ligament (LCL) tear than normal.3 The relationship between the stabilizing structures of the knee and the subchondral BMLs and OAPC, and between meniscus extrusion and osteophytes, as well as the relationship among the stabilizing structures of the knee3.1 The association of the stabilizing structures of the knee with subchondral BMLs and OAPCResults show the total meniscus and cartilage defect was positive related to subchondral BMLs and OAPC. MFC cartilage defect, the anterior horn of the medial meniscus tear and extrusion were positive related to MFC BMLs. MT cartilage defect and the anterior horn of the medial meniscus tear were positive related to MT BMLs. LFC cartilage defect was positive related to LFC BMLs. LT cartilage defect and the anterior horn of the lateral meniscus tear were positive related to LT BMLs. There was no relationship between the anterior horn of the lateral meniscus extrusion and the LT BMLs.3.2 The relationship among the stabilizing structures of the kneePositive correlation was found between the medial cartilage defect and the medial meniscus tear or extrusion, as well as the medial meniscus tear and extrusion, the lateral cartilage defect and the lateral meniscus tear or extrusion, the lateral meniscus tear and extrusion. In other words, the more severely the cartilage defects, the more severely of the meniscus tear or extrusion at the corresponding side.3.3 The relationship between meniscus extrusion and osteophytesResults show the anterior and posterior horn of the meniscus extrusion was positive related to osteophytes. In other words, the more severely the meniscus extrusion was found, the larger the osteophytes.4 The discrepancy of the range of the subchondral focal lesions and the severity of the meniscus extrusion between the BMI of the man and women overweight and normalThe stabilizer failure group was divided into two groups by the BMI overweight and normal. The results show the LFC, MT and LT BMLs of the overweighted man were larger than the man with normal weight, but the OAPC and MT BMLs were not affected by weight, and the severity of the medial and lateral meniscus extrusion of the man was not affected by weight. It indicated that man overweight would induce the formation of LFC, MT and LT BMLs easily.MFC BMLs and OAPC of the overweighted woman were larger than the normal weight woman, but the two lesions were not affected by weight. The degree of the medial meniscus extrusion of the overweighted woman was more severely than the normal weight woman, but the degree of the lateral meniscus extrusion was not affected by weight. It indicated that woman overweight would induce the formation of MFC BMLs and OAPC and medial meniscus extrusion easily.5 The relationship among the range of the subchondral BMLs and OAPC, the abnormality of the stabilizer structrue, and other possible factors.Tested by logistic regression method, the range of MFC BMLs is mainly affected by the anterior horn of the medial meniscus extrusion, and followed by the anterior horn of the medial meniscus tear, MFC cartilage defect and age.The range of MT BMLs is mainly affected by MT cartilage defect, and followed by the anterior horn of the medial meniscus tear and age.The range of LFC BMLs is mainly affected by LFC cartilage defect, and followed by the age.The range of LT BMLs is mainly affected by the gender, and followed by LT cartilage defect, the anterior horn of the lateral meniscus tear and BMI.The range of MFC OAPC is mainly affected by the anterior horn of the medial meniscus tear, and followed by BMI.The range of MT OAPC is mainly affected by MT cartilage defect, and followed by the gender.The range of LFC OAPC is mainly affected by LFC cartilage defect, and followed by LFC BMLs.The range of LT BMLs is mainly affected by LT cartilage defect, and followed by the anterior horn of the lateral meniscus tear.The range of the gross BMLs is mainly affected by cartilage defect, and followed by the meniscus abnormality and age.The range of the gross OAPC is mainly affected by cartilage defect, and followed by the meniscus abnormality, the gross BMLs, BMI and age.6 Because of the simultaneous appearance of the BMLs and OAPC, we listed it and make a comparision with the pure BMLs and OAPC.Results show there was significant difference among the cartilage and PCL of the there groups, and the defect degree of them form high to low is the simultaneous appearance of the BMLs and OAPC, the pure BMLs and the pure OAPC group by turns, but there is no significant difference among the meniscus tear, extrusion and ACL of the three groups.7 The BMLs and OAPC of the stabilizer failure group were categorized by the patient history, and they were analyzed about the influence by the stress history.The stress history was classified into several factors as follows: the long-term stress, recent stress, trauma (more than half a year), stress and trauma and no stress or trauma. The long-term stress indicated centralized over use of the knee for more than one year, and recent stress indicates heavier exercises the recent one year.The BMLs frequency of the patients with long-stress history was significant higher than the patients with trauma. The OAPC frequency of the patients with on stress or trauma was significant higher than the patients with long-term stress and recent stress.Conclusion:1 Articular stabilizer structure defect would induce the formation of subchondral BMLs and OAPC, and the main factor was the cartilage defect.2 BMLs may be the risk factor of the OAPC formation, and they may have same pathogenesis and represented pathologic different stages. Deduced that BMLs represented early stage, and progressed to OAPC eventually.3 Overuse could induce the formation of subchondral BMLs easily.4 The degree of the cartilage and PCL defect of the simultaneous appearance of the BMLs and OAPC was more severely than the two lesions individualism.5 Man overweight could induce the formation of LFC, MT, and LT BMLs, and woman overweight could induce the formation of BMLs at weight-bearing area, as well as the medial meniscus extrusion.6 Interdependence and interaction relationship was found among the stabilizer structures of the knee, and osteophytes induce meniscus extrusion.