Is the Bare Spot reliable for the bone loss measurement?

Background: To evaluate the reliability of the Bare Spot (BS) as an anatomical landmark for the intra-operative definition of bone loss in anterior shoulder instability.

Methods: The distances from the BS to the anterior (BS-A), posterior (BS-P) and inferior margins of the glenoid cavity were determined both under arthroscopic visualization and by an open approach in 20 shoulders.

Results: The BS did not coincide with the centre of the glenoid cavity of the studied shoulders because the BS-P distance was greater than the BS-A distance ( p  < 0.05) and was located 40% closer to the anterior margin. The authors suggest a correction factor: BP-A × 1.25/BP-P = 1.

Conclusions: The BS is located at a mean distance of 40% of the joint diameter, relative to the anterior margin of the glenoid. This point may be used as a landmark, using a correction factor of its mostly anterior positioning. Arthroscopy was reliable for bone measurements of the shoulder joint.