title: Posterior chondrolabral cleft: clinical significance and associations with shoulder instability.
abstract: BACKGROUND
  A high signal intensity cleft between the labrum and articular cartilage of the posterior glenoid is commonly visible on MRI and has been suggested to be anatomic variation [3, 10, 23]. The association of a posterior cleft with variations in glenoid morphology or with shoulder instability is unknown.
  
  
  OBJECTIVE
  The purposes of this study were to determine if posterior chondrolabral clefts are associated with variations in glenoid morphology, and to determine if they are associated with shoulder instability.
  
  
  METHODS
  Shoulder MRI was performed in 1,264 shoulders, 1,135 male (89.8%), and 129 female (10.2%). A musculoskeletal radiologist blinded to history and outcomes evaluated the MR images for linear high signal intensity at the posterior chondrolabral junction and a rounded or truncated contour of the posterior glenoid. Glenoid version and depth were measured. Patients were followed prospectively for shoulder instability for 4 years. Univariate and multivariate statistical analysis were performed.
  
  
  RESULTS
  Posterior chondrolabral cleft was present in 114/1,264. Posterior chondrolabral cleft was associated with a rounded or truncated posterior glenoid. There were 9.5° retroversion in shoulders with a posterior cleft, and 7.7° retroversion in shoulders without a cleft. Shoulders with a posterior chondrolabral cleft were more likely to develop shoulder instability.
  
  
  CONCLUSIONS
  Posterior chondrolabral clefts are not uncommon on MRI. They are associated with a rounded or truncated posterior glenoid and a small but significant increase in glenoid retroversion. They are associated with shoulder instability.
authors.affiliation: Department of Radiology, Landstuhl Regional Medical Center, CMR 402, Box 966 APO,, AE 09180 Landstuhl, Rhineland-Pfalz Germany.
authors.forename: Scot E
authors.initials: SE
authors.lastname: Campbell
authors.affiliation: Keller Army Hospital, US Military Academy, West Point, NY USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Dewitt
authors.affiliation: Keller Army Hospital, US Military Academy, West Point, NY USA.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Cameron
authors.affiliation: Keller Army Hospital, US Military Academy, West Point, NY USA.
authors.forename: Adrianne K
authors.initials: AK
authors.lastname: Thompson
authors.affiliation: Keller Army Hospital, US Military Academy, West Point, NY USA.
authors.forename: Brett D
authors.initials: BD
authors.lastname: Owens
keywords: glenoid version; posterior chondrolabral cleft; shoulder MRI; shoulder instability