title: A new method to evaluate glenoid erosion in instable shoulder.
abstract: BACKGROUND
  We aimed to establish values and parameters using multislice reconstruction in axial computerized tomography (CT) in order to quantify the erosion of the glenoid cavity in cases of shoulder instability.
  
  
  METHODS
  We studied two groups using CT. Group I had normal subjects and Group II had patients with shoulder instability. We measured values of the vertical segment, the superior horizontal, medial and inferior segments, and also calculated the ratio of the horizontal superior and inferior segments of the glenoid cavity in both normal subjects and those with shoulder instability. These variables were recorded during arthroscopy for cases with shoulder instability.
  
  
  RESULTS
  The mean values were 40.87 mm, 17.86 mm, 26.50 mm, 22.86 mm and 0.79 for vertical segment, the superior horizontal, medial and inferior segments, and the ratio between horizontal superior and inferior segments of the glenoid cavity respectively, in normal subjects. For subjects with unstable shoulders the mean values were 37.33 mm, 20.83 mm, 23.07 mm and 0.91 respectively. Arthroscopic measurements yielded an inferior segment value of 24.48 mm with a loss of 2.39 mm (17.57%). The ratio between the superior and inferior segments of the glenoid cavity was 0.79. This value can be used as a normative value for evaluating degree of erosion of the anterior border of the glenoid cavity. However, values found using CT should not be used on a comparative basis with values found during arthroscopy.
  
  
  CONCLUSIONS
  Computerized tomographic measurements of the glenoid cavity yielded reliable values consistent with those in the literature.
authors.affiliation: Department of Orthopaedics and Traumatology, Faculdade de Medicina do ABC, Av, Príncipe de Gales, 821,, 09060-650 Santo Andre, SP, Brazil. rob.ike@hotmail.com.
authors.forename: Roberto Y
authors.initials: RY
authors.lastname: Ikemoto
authors.forename: Joel
authors.initials: J
authors.lastname: Murachovsky
authors.forename: Luis G
authors.initials: LG
authors.lastname: Nascimento
authors.forename: Rogerio S
authors.initials: RS
authors.lastname: Bueno
authors.forename: Luiz Henrique
authors.initials: LH
authors.lastname: de Oliveira
authors.forename: Edson N
authors.initials: EN
authors.lastname: Fujiki
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: de Abreu
authors.forename: Vitor E
authors.initials: VE
authors.lastname: Valenti
authors.forename: Sergio L
authors.initials: SL
authors.lastname: Checchia