title: Intra and inter-examiner reliability of the subacromial impingement index.
abstract: OBJECTIVE
  The present study aimed to assess the reliability of intra and inter-examiner subacromial impingement index (SII) measures obtained from radiographs.
  
  
  METHODS
  Thirty-six individuals were enrolled and divided into two groups: control group, composed of 18 volunteers in good general health without shoulder problems, and a group of 18 patients with subacromial impingement syndrome (SIS). Radiographic images were taken with the dominant upper limb in neutral rotation, while the volunteers held their arm at 90 degrees of abduction in the frontal plane. The beam of radiation at 30 degrees craniocaudal inclination was used to provide an antero-posterior image view. Three blinded examiners each performed three measurements from the subacromial space (SS) and the anatomical neck of the humerus (NH). The SII was calculated as the ratio of the SS and the NH measures. The mean values of SII were compared using t-tests. The intra-class correlation coefficient (ICC) was used to assess intra- and inter-examiner reliability of the measures.
  
  
  RESULTS
  The mean values of SII were greater for the control group (0.12) than for the SIS group (0.08; p = 0.0071). SII measurements showed excellent intra (0.96-0.99) and inter-examiner reliability (0.94) for both the control and SIS group.
  
  
  CONCLUSIONS
  The results of this study show the potential use of the SII; a greater mean value for the control group compared to the SIS group and excellent reliability for intra- and inter-examiner measurement. Validation studies of the index should be conducted to correlate the index with clinical findings from subacromial impingement syndrome.
authors.affiliation: Ribeirão Preto School of Medicine, University of São Paulo, Paineiras St, Monte Alegre, 14049-900, Ribeirão Preto, SP, Brazil.
authors.forename: Carlos Eduardo Sala
authors.initials: CE
authors.lastname: Ramos
authors.forename: Felipe Varella
authors.initials: FV
authors.lastname: Ferreira
authors.forename: Guilherme de Carvalho
authors.initials: Gde C
authors.lastname: Sposito
authors.forename: Marcello Henrique
authors.initials: MH
authors.lastname: Nogueira-Barbosa
authors.forename: Anamaria Siriani
authors.initials: AS
authors.lastname: de Oliveira
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D012015:Reference Standards; D019534:Shoulder Impingement Syndrome / Q000000981:diagnostic imaging