Impact of age on glenoid size: three-dimensional computed tomographic analysis of glenoid anatomy

Abstract

ObjectivePredictors of glenoid size are not fully understood. Reported factors include ethnicity, sex, and height. However, many studies have been conducted with relatively younger age groups on the assumption that no significant change in the size of the glenoid fossa occurs after the termination of bone growth. The purpose of this study was to examine glenoid size in a population representing the age groups eligible for rotator cuff surgery and to identify the influence of age on the size of the glenoid. MethodsThis retrospective review included 380 shoulders in 380 patients (151 females and 229 males; mean age: 67.2 ± 10.1 years; range: 27–89 years) who underwent preoperative three-dimensional computed tomography (3D-CT) evaluation and elective shoulder surgery (open or arthroscopic). The exclusion criteria were: history of prior shoulder surgery or glenoid fractures; history of shoulder instability; patients aged younger than 25 years; and those with advanced glenohumeral osteoarthritis. Anatomic parameters of the glenoid (height and width) were measured using 3D-CT images. A generalized linear model with the gamma distribution (multivariate gamma regression) was used in the analysis with the glenoid size (height or width) as the dependent variable. Initial exploratory models included all independent variables, followed by the stepwise selection of variables based on the P value, variance inflation factor, and Akaike’s information criterion for developing the final models. ResultsThe final analytical model showed that age was a significant predictor in both glenoid height and width. The mean glenoid width was 31.2 mm in men and 26.1 mm in women, and the mean glenoid height was 41.1 mm in men and 38.8 mm in women. Other factors that were significant were sex, body height, and hand dominancy. The analysis models accounted for 65% of the glenoid height (pseudo r-squared = 0.65; likelihood ratio test, P = .011) and 73% of the glenoid width (pseudo r-squared = 0.73; likelihood ratio test, P < .0001). ConclusionThis study showed that predictors of glenoid size (height and width) included age. Other positive predictors were shown to be taller body height, male gender, and dominant hand. The influence of rotator cuff tear was not observed.