The osseous morphology of nondegenerated shoulders shows no side-related differences in elderly patients: an analysis of 102 computed tomography scans.

BACKGROUND: A precise understanding of glenohumeral anatomy is required to optimize preoperative planning in shoulder joint arthroplasty, which is difficult in the presence of degenerative disease. In unilateral disease, the contralateral shoulder can be used as a representation of normal anatomy; however, intrasubject differences in shoulder morphology have not been investigated. METHODS: A retrospective study of all patients aged >65 years who received whole body computed tomography at our trauma center from 2010 through 2014 was conducted. Right and left shoulder computed tomography scans were examined, and the following anatomic parameters were measured: humeral head diameter in anteroposterior and axial views, glenoid diameter in anteroposterior and axial views, glenoid surface, scapula neck depth, neck-shaft angle, glenoid inclination, glenoid/head ratio, and glenoid version. Patients with inadequate scan quality, osseous lesions, pre-existing anatomic abnormality, or metallic implant at the shoulder region and significant osteoarthritis were excluded. RESULTS: The study analyzed 102 shoulders of 51 patients. Mean age was 71.4 ± 8.2 years. Humeral head and glenoid diameters, scapula neck depth (right, 36 ± 8 mm; left, 36 ± 7 mm; P = .684), glenoid/head ratio (right, 0.6 ± 0.1; left, 0.6 ± 0.0; P = .961), and glenoid surface (right, 790 ± 152 mm(2); left, 754 ± 134 mm(2); P = .215) showed no significant side-related differences. In addition, no significant difference was found regarding the neck-shaft angle (P = .211) and glenoid anteversion or retroversion (right, 65% [n = 33] anteversion and 35% [n = 18] retroversion; left, 69% [n = 35] anteversion and 31% [n = 16] retroversion; P = .417). CONCLUSION: There are no significant side-dependent differences in the osseous anatomy of the glenohumeral joint. In patients with unilateral shoulder degeneration, the contralateral shoulder can provide reference values during the planning of shoulder replacement surgery.

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.