title: Value of knee MRI in the diagnosis and management of knee disorders.
abstract: The primary objectives of this study were to determine how frequently knee magnetic resonance imaging (MRI) changes (1) diagnosis, (2) diagnostic confidence, and (3) management. A secondary objective was to correlate these changes with specific patient/physician characteristics and develop a prediction model using these characteristics. Six orthopedic specialists prospectively completed surveys when ordering knee MRI (n=93). Pre-MRI surveys recorded history, symptoms, signs, diagnosis, diagnostic confidence, and planned management. Post-MRI surveys recorded diagnosis, confidence, and planned management. Changes in diagnosis, management, and diagnostic confidence were correlated with patient/physician characteristics using chi-square and logistic regression tests. A multiple variable model was created with the most significant variables from the univariate analysis, and a c-index was used for cross-validation. Magnetic resonance imaging changed diagnosis in 29.3% and management in 25.3% of cases. Confidence in diagnoses after MRI increased, on average, by 10.6%. Change in diagnosis was significantly correlated with lateral joint line pain (P=.012) and tenderness (P=.006). The 3 most significant predictors for change in management were ligament pathology (P=.017), medial-sided pain/tenderness (P=.051), and age (P=.133). A 3-variable model using these predictors was significantly better than chance alone at predicting management changes (c-index: model=0.766; cross-validation=0.661). Magnetic resonance imaging frequently changed diagnosis and management and improved diagnostic confidence in a large minority of patients with internal derangement of the knee, even after evaluation by subspecialized physicians. A statistical model using specific patient characteristics can be created to predict when MRI will change management.
authors.forename: Naveen
authors.initials: N
authors.lastname: Subhas
authors.forename: Sunny H
authors.initials: SH
authors.lastname: Patel
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Obuchowski
authors.forename: Morgan H
authors.initials: MH
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019091:Critical Pathways / Q000706:statistics & numerical data; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis* / Q000628:therapy*; D007718:Knee Injuries / Q000175:diagnosis* / Q000628:therapy*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult