Glenoid Bare Area: Arthroscopic Characterization and Its Implications on Measurement of Bone Loss

Purpose The purpose of this study was to characterize arthroscopically the frequency and location of the glenoid bare area. Methods Three fellowship-trained orthopaedic sports surgeons evaluated and characterized the bare area of the glenoid in 52 consecutive patients undergoing arthroscopic surgery of the shoulder without a diagnosis of instability. Among the patients with a visible bare area, the position was measured, and when eccentrically located, an apparent bone loss or gain was calculated. Results The bare area of the glenoid was observed in only 48% of patients undergoing arthroscopic surgery, and when observed, it was at the center only 37% of the time. Of the glenoids with visible bare areas, 8% were located anteriorly enough to result in an apparent bone loss calculation of greater than 20%. An additional 25% of visible bare areas were posteriorly located, resulting in an apparent bone gain. Conclusions The glenoid bare area is a variably visible and eccentric landmark on the glenoid and thus should not be used as the sole reference point to measure glenoid bone loss. Level of Evidence Level IV, retrospective observational study.