Osteoarthritis of the glenohumeral joint leads to global degeneration of the shoulder and often results in humeral or glenoid osteophytes. It is established that the axillary neurovascular bundle is in close proximity to the glenohumeral capsule. Similar to other compressive neuropathies, osteophytic impingement of the axillary nerve could result in axillary nerve symptoms. The purpose of this study was to compare the proximity of the axillary neurovascular bundle to the inferior humerus in shoulders to determine distance of the neurovascular bundle as the osteophyte (goat's beard) of glenohumeral osteoarthritis develops. In this IRB approved study, preoperative MRI's of 98 shoulders (89 patients) with primary osteoarthritis (OA group) were compared to 91 shoulders (86 patients) with anterior instability (Control group). For MRI measurements (mm) two coronal-oblique T1 or proton density weighted images were selected for each patient located at 5 and 6 o'clock position of the glenoid in the parasagittal plane. Humeral head diameter to standardize the glenohumeral measurements, size of the spurs, and 6 measurements between osseus structures and axillary neurovascular bundle were obtained on each image using a calibrated measurement system (Stryker Office PACS Power Viewer). Level of significance was set at p>.05.Introduction
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