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

ABSTRACT

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.