title: [Study on correlation between pain grading, stage of necrosis and bone marrow-edema in nontraumatic osteonecrosis of femoral head].
abstract: OBJECTIVE
  To explore the correlation between pain grading, stage of necrosis and bone marrow edema (BME) in nontraumatic osteonecrosis of femoral head (NONFH) so as to strengthen understandings about clinical significance of BME in NONFH.
  
  
  METHODS
  From October 2004 to October 2006, 97 patients (149 hips) with NONFH were treated. There were 68 males and 29 femals with an average age of 38.8 years (19-62 years). The disease course was from 20 days to 4 years. BME was identified grade 0 to grade 2 according to MRI. Based on grading scale of pain, pain grading were divided into no pain (grade 0), mild pain (grade 1) and moderate or severe pain (grade 2). According to Association Research Circulation Osseous staging system, NONFH were divided into I-IV stages. The incidence rate of BME in each pain grading and stages of necrosis was analyzed respectively. Contingency table analyses and rank sum tests were used to compare the difference of pain grading and stages of necrosis among these groups.
  
  
  RESULTS
  The total incidence rate of BME was 73.15% (109/149), the incidence rates were 84.38% in pain groups (108/128) and 94.12% in the grade 2 (32/34). Pain grading correlated with BME rating (P < 0.001). The results of rank sum tests for several independent samples showed significant difference in BME among pain groups(P < 0.001). With the advance of pain scale, the mean rank of BME increased gradually (28.19 for grade 0, 78.94 for grade 1 and 96.12 for grade 2). BME was more commonly and clearly seen in stage II (77.05%) and stage III (82.81%) of NONFH. Stage I-III of NONFH correlated with BME rating (P < 0.001). The results of rank sum tests showed significant difference in BME rating among three stages (P < 0.001). With the advance of disease, the rank of BME rating increased gradually (39.07 for grade 0, 60.16 for grade 1 and 86.15 for grade 2).
  
  
  CONCLUSIONS
  BME is a sign that is accompanied with NONFH. The probability and extent of BME correlated well with the pain and stage of NONFH. The condition of BME can be used as a index for the appraisal of advancement of disease and the judgment of treatment result.
authors.affiliation: Department of Orthopaedics, 1st Affiliated Hospital of Guangzhou Traditional Chinese Medicine University, Guangzhou Guangdong, 510405, P. R. China. hewei1123@21cn.com
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Qin
authors.initials: Q
authors.lastname: Zeng
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Pang
authors.forename: Ping
authors.initials: P
authors.lastname: Zeng
authors.forename: Haibin
authors.initials: H
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Yuan
mesh_terms: D000328:Adult; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000473:pathology*; D004487:Edema / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology*; D005271:Femur Head Necrosis / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000473:pathology; D010147:Pain Measurement; D012189:Retrospective Studies; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D055815:Young Adult