title: Bone marrow edema of the mandibular condyle related to internal derangement, osteoarthrosis, and joint effusion.
abstract: OBJECTIVE
  The purpose of this prospective study was to evaluate whether common magnetic resonance imaging (MRI) variables such as temporomandibular joint (TMJ) internal derangement, osteoarthrosis, and effusion may predict the diagnostic group of bone marrow edema of the mandibular condyle.
  
  
  METHODS
  The relationship between bone marrow edema and TMJ disc displacement, osteoarthrosis, and effusion was analyzed in MRIs of 120 TMJs in 73 consecutive patients with TMJ pain and/or a clinical diagnosis of TMJ internal derangement type III (disc displacement without reduction). The diagnostic bone marrow edema group was comprised of 54 TMJs in 40 patients with a unilateral or bilateral MRI diagnosis of bone marrow edema. The control group consisted of 66 non-bone marrow edema TMJs in 33 patients with a bilateral MRI finding of an absence of bone marrow edema. A logistic regression analysis was used to compute the odds ratios for internal derangement, osteoarthrosis, and effusion for non-bone marrow edema TMJs (n = 66) versus TMJs with bone marrow edema (n = 54).
  
  
  RESULTS
  Using Chi;(2) analysis for pair-wise comparison, the TMJ-related data showed a significant relationship between the MR imaging findings of TMJ bone marrow edema and those of internal derangement (P = .000), osteoarthrosis (P = .000), and effusion (P = .010). Of the MRI variables considered simultaneously in the multiple logistic regression analysis, osteoarthrosis (P = .107) and effusion (P = .102) dropped out as nonsignificant in the diagnostic bone marrow edema group when compared with the control group. The odds ratio for individuals with an internal derangement showing bone marrow edema was strong (3.6:1) and highly significant (P = .000). Significant increases in risk of bone marrow edema occurred with disc displacement without reduction and osteoarthrosis (9.2:1) (P = .000) and disc displacement without reduction and effusion (6.4:1) (P = .002).
  
  
  CONCLUSIONS
  The results suggest that the MR imaging findings for TMJ bone marrow edema are related to those of internal derangement, osteoarthrosis, and effusion. However, the data re-emphasize the aspect that internal derangement, osteoarthrosis, and effusion may not be regarded as the unique and dominant factors in defining TMJ bone marrow edema instances.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Innsbruck, Innsbruck, Austria. Ruediger_Emshoff@hotmail.com
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Emshoff
authors.forename: Iris
authors.initials: I
authors.lastname: Brandlmaier
authors.forename: Christoph
authors.initials: C
authors.lastname: Schmid
authors.forename: Stefan
authors.initials: S
authors.lastname: Bertram
authors.forename: Ansgar
authors.initials: A
authors.lastname: Rudisch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001855:Bone Marrow Diseases / Q000150:complications* / Q000503:physiopathology; D016009:Chi-Square Distribution; D004487:Edema / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000150:complications* / Q000503:physiopathology; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008335:Mandibular Condyle / Q000473:pathology*; D008336:Mandibular Diseases / Q000150:complications / Q000503:physiopathology; D016555:Matched-Pair Analysis; D008875:Middle Aged; D016017:Odds Ratio; D010003:Osteoarthritis / Q000150:complications* / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D013582:Synovial Fluid / Q000502:physiology*; D019224:Temporomandibular Joint Disc / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000150:complications* / Q000503:physiopathology