Purpose: Our purpose was to evaluate the distance from the bony edge of the glenoid to the visible (or macroscopic) demarcation at the junction of the labrum and the articular cartilage.
Methods: Ten fresh-frozen cadaveric upper extremity specimens were dissected. The shoulder was disarticulated and periarticular structures were removed, leaving the glenoid with the labrum attached. The macroscopic edge of the glenoid was then marked with a drill at the 3-, 4-, 5-, 6-, 7, 8-, and 9-o'clock positions, as defined by a clock face (right) and a reverse clock face (left). Soft tissue and cartilage were then removed, and the distance from the outer edge of the drill hole to the bony rim was measured.
Results: The mean distance from the bony edge in hourly intervals starting at the 3-o'clock position anteriorly and extending to the 9-o'clock position posteriorly was 4.03 mm (range, 2.1 to 5.21 mm; SD, 0.96 mm), 4.2 mm (range, 2.1 to 5.31 mm; SD, 0.97 mm), 4.51 mm (range, 3.1 to 5.2 mm; SD, 0.91 mm), 5.14 mm (range, 3.1 to 7 mm; SD, 1.38 mm), 3.24 mm (range, 1.1 to 5.2 mm; SD, 1.4 mm), 3.78 mm (range, 1 to 6 mm; SD, 1.6 mm), and 4.28 mm (range, 2.1 to 7.3 mm; SD, 1.51 mm), respectively. A trend was noted for significant differences between locations, but this did not reach statistical significance (analysis of variance, P = .086).
Conclusions: The macroscopic edge of the labrum on the glenoid face does not correspond to the bony edge of the glenoid. The labrum overlaps onto the bony surface of the glenoid from a minimum of 1.6 mm to a maximum of 7.3 mm.
Clinical relevance: Our findings provide anatomic data that enhances the arthroscopist's ability to anatomically reconstruct the glenoid labrum.