Age-dependent variation of glenohumeral anatomy: a radiological study.

Purpose: Profound knowledge of variations in shoulder anatomy is gaining relevance in daily clinical work. In our study, we examine age-dependent variations of glenohumeral parameters in healthy individuals.

Methods: In this analysis, 774 severely injured patients who received a whole-body computed tomography (CT) scan were included. Patients with shoulder fractures were excluded. The resulting scans were split into two groups: patients younger than 25 (group 1) and older than 60 years (group 2). These groups were divided into four subgroups according to gender. Shoulder scans with advanced osteoarthritis were then removed. In order to maintain equal group size, redundant patients were randomly removed.

Results: A total of 210 measurements from 106 patients were included. The humeral head diameter (group 1: 41.6 ± 3.7 mm, group 2: 44.5 ± 3.7 mm, p < 0.001) and glenoid surface (group 1: 627.0 ± 110.8 mm(2), group 2: 763.9 ± 148.5 mm(2), p < 0.001) showed higher values in the group of older patients. Older patients also had a higher glenoid inclination (group 1: 50.9 ± 6.9°, group 2: 55.7 ± 8.8°, p < 0.001) as well as an increased glenoid to head ratio (group 1: 0.61 ± 0.04, group 2: 0.64 ± 0.05, p < 0.001).

Conclusions: Increased sizes of humeral head and glenoid surface are present in older patients without signs of osteoarthritis. Moreover, in patients with increased age more glenoid inclination as well as an increased glenoid to head ratio was revealed. These age-dependent anatomical parameters should be considered during planning of operative procedures of the shoulder joint.