title: Reliability and precision of stress sonography of the ulnar collateral ligament.
abstract: OBJECTIVE
  Musculoskeletal sonography has emerged as an additional diagnostic tool that can be used to assess medial elbow pain and laxity in overhead throwers. It provides a dynamic, rapid, and noninvasive modality in the evaluation of ligamentous structural integrity. Many studies have demonstrated the utility of dynamic sonography for medial elbow and ulnar collateral ligament (UCL) integrity. However, evaluating the reliabilityand precision of these measurements is critical if sonography is ultimately used as a clinical diagnostic tool. The purpose of this study was to evaluate the reliability and precision of stress sonography applied to the medial elbow.
  
  
  METHODS
  We conducted a cross-sectional study during the 2011 baseball off-season. Eighteen National Collegiate Athletic Association Division I pitchers were enrolled, and 36 elbows were studied. Using sonography, the medial elbow was assessed, and measurements of the UCL length and ulnohumeral joint gapping were performed twice under two conditions (unloaded and loaded) and bilaterally.
  
  
  RESULTS
  Intraclass correlation coefficients (0.72-0.94) and standard errors of measurements (0.3-0.9 mm) for UCL length and ulnohumeral joint gapping were good to excellent. Mean differences between unloaded and loaded conditions for the dominant arms were 1.3 mm (gapping; P < .001) and 1.4 mm (UCL length; P < .001).
  
  
  CONCLUSIONS
  Medial elbow stress sonography is a reliable and precise method for detecting changes in ulnohumeral joint gapping and UCL lengthening. Ultimately, this method may provide clinicians valuable information regarding the medial elbow's response to valgus loading and may help guide treatment options.
authors.affiliation: Brown University Alpert Medical School, Affinity Sports Medicine, East Greenwich, Rhode Island USA (D.B.); and Department of Family Medicine, Division of Sports Medicine (J.A.), and Departments of Health Education and Promotion (A.S.K.), Family Medicine (K.Y.), and Athletics (Z.W.), East Carolina University, Greenville, North Carolina USA david_bica@brown.edu.
authors.forename: David
authors.initials: D
authors.lastname: Bica
authors.affiliation: Brown University Alpert Medical School, Affinity Sports Medicine, East Greenwich, Rhode Island USA (D.B.); and Department of Family Medicine, Division of Sports Medicine (J.A.), and Departments of Health Education and Promotion (A.S.K.), Family Medicine (K.Y.), and Athletics (Z.W.), East Carolina University, Greenville, North Carolina USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Armen
authors.affiliation: Brown University Alpert Medical School, Affinity Sports Medicine, East Greenwich, Rhode Island USA (D.B.); and Department of Family Medicine, Division of Sports Medicine (J.A.), and Departments of Health Education and Promotion (A.S.K.), Family Medicine (K.Y.), and Athletics (Z.W.), East Carolina University, Greenville, North Carolina USA.
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Kulas
authors.affiliation: Brown University Alpert Medical School, Affinity Sports Medicine, East Greenwich, Rhode Island USA (D.B.); and Department of Family Medicine, Division of Sports Medicine (J.A.), and Departments of Health Education and Promotion (A.S.K.), Family Medicine (K.Y.), and Athletics (Z.W.), East Carolina University, Greenville, North Carolina USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Youngs
authors.affiliation: Brown University Alpert Medical School, Affinity Sports Medicine, East Greenwich, Rhode Island USA (D.B.); and Department of Family Medicine, Division of Sports Medicine (J.A.), and Departments of Health Education and Promotion (A.S.K.), Family Medicine (K.Y.), and Athletics (Z.W.), East Carolina University, Greenville, North Carolina USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Womack
mesh_terms: D017885:Collateral Ligaments / Q000000981:diagnostic imaging*; D004551:Elbow Joint / Q000000981:diagnostic imaging*; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D008297:Male; D056888:Patient Positioning / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014457:Ulna / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult
keywords: musculoskeletal ultrasound; precision; reliability; sonography; ulnar collateral ligament