Influence of the Labrum on Version and Diameter of the Glenoid: A Morphometric Study Using Magnetic Resonance Images

摘要

Purpose: To use magnetic resonance imaging to determine the influence of the labrum on both the osseous version and effective diameter of the glenoid. Methods: This was a retrospective, cross-sectional study of patients with shoulder pain who underwent MRI between February 2014 and February 2015. The morphology of the glenoid labrum and glenoid was scanned with a 3-T magnetic resonance imaging scanner, and variables were measured by use of IntelliSpace PACS Enterprise. Patients were included if they were aged between 18 and 40 years and the radiologist reported a normal glenohumeral joint or if they were young patients aged less than 30 years with acute traumatic isolated partial-or full-thickness tears of the rotator cuff with a history of symptoms of less than 3 months. A pilot study was conducted with 3 observers and 3 repeated measurements at intervals to determine the interobserver and intraobserver reliability. Data analysis included descriptive statistics of measured variables, as well as paired Student t tests to determine the relative difference between labral and osseous morphometric variables. Results: Excellent inter-rater reliability (0.95-0.96) and intrarater reliability (0.93-0.98) were obtained in the pilot study of 20 patients. The study population was composed of 100 patients with a mean age of 37.3 years (standard deviation [SD], 11.8 years), having a gender distribution of 56 male and 44 female patients; there were 53 right and 47 left shoulders. The glenoid osseous version measured -5.7 degrees (SD, 5.3 degrees), and the labral version measured -10 degrees (SD, 5.5 degrees); the glenoid osseous diameter measured 28.0 mm (SD, 3.3 mm), and the labral diameter measured 31.9 mm (SD, 3.2 mm). The labrum significantly increased the version by 4.3 degrees (P = .001) and significantly increased the diameter by 3.9 mm (P = .001). Conclusions: The results of this study showed that the labrum increased the effective glenoid version by 75% (4.3 degrees of retroversion) and the effective glenoid diameter by 14% (3.9 mm).