Purpose: In this cadaveric study, we aim to define the basic anatomy of the anterior glenoid with attention to the relationships of calcified cartilage, capsulolabral complex, and osseous morphology of the anterior glenoid.
Methods: Seventeen cadaveric glenoid specimens (14 male, 3 female, mean age 53.9 ± 10) were imaged with micro-computed tomography (CT) and embedded in poly-methyl-methacrylate. Specimens were included for final analysis only if the entire glenoid articular cartilage, labrum, capsule, and biceps insertion were pristine and without evidence of injury, degeneration, or damage during the preparation process. Group 1 members (n = 9) were axially sectioned through 3 to 9 o'clock and 4 to 8 o'clock; group 2 members (n = 8) were radially sectioned through 3, 4, 5, and 9 o'clock. A scanning electron microscope (SEM) analysis quantified the percentage of bone within a 5 × 2.5 mm region at the glenoid rim. Micro-CT, SEM, and light microscopy evaluated the capsulolabral complex and calcified fibrocartilage.
Results: A 7 ± 2.1 mm region of calcified fibrocartilage at 4 o'clock was identified from the articular face to the medial glenoid neck supporting the overlying capsulolabral footprint and was >3× thicker at the articular attachment (316 ± 153 μm) versus the glenoid neck (92 ± 66 μm). At 3 to 9 o'clock and 4 to 8 o'clock 79.2% ± 5.4% and 75.2% ± 7.8% of the glenoid osseous width was covered with articular cartilage. The labrum accounted for 13.1% ± 3.4% of the glenoid width at 4 o'clock. SEM analysis demonstrated decreased glenoid bone density at 3, 4, and 5 o'clock (P ≤ .015) and no difference (P = .448) at 9 o'clock versus central subchondral bone.
Conclusions: The capsulolabral footprint contributes significantly to the glenoid face, inserts directly adjacent to the articular cartilage, and extends medially along the glenoid neck. A layer of calcified fibrocartilage lies immediately beneath the capsulolabral footprint and is 3× thicker at the articular insertion compared with the glenoid neck. Lastly, there is a bone density gradient at the anterior-inferior rim versus the central subchondral bone.
Clinical relevance: Arthroscopic Bankart repair has been reported to have a significant failure rate in many settings. It is felt that reproducing anatomy with the repair could help improve outcomes. Based on this study's findings, an arthroscopic Bankart technique that most closely reproduces native anatomy and potentially optimizes soft-tissue healing could be performed. This includes removal of 1 to 2 mm of articular cartilage from the glenoid face with anchor placement at this location to appropriately reposition the capsulolabral complex.
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