Arthroscopic Anchor Placement During Shoulder Anterior Labral Repair in the Beach-Chair Versus the Lateral Decubitus Position: An Imaging Analysis.

Background: Arthroscopic shoulder capsuloligamentous repair can be performed in the beach-chair (BC) or lateral decubitus (LD) position. Patient positioning may influence anchor placement. Limited research exists evaluating these 2 positioning techniques, specifically with respect to anchor position and trajectory. Purpose/Hypothesis: The purpose of this study was to perform a cadaveric imaging analysis of arthroscopic anterior shoulder stabilization in the LD and BC positions. It was hypothesized that repairs performed in the LD position would demonstrate more accurate anterior inferior anchor positioning. Study Design: Controlled laboratory study. Methods: Nine matched pairs of cadaveric shoulders (18 total shoulders) were used. Specimens underwent arthroscopic anterior inferior labral repair using 3 suture anchors placed in the 3:30, 4:30, and 5:30 positions. Repairs were performed by 2 fellowship-trained orthopaedic surgeons each trained in a respective technique. Specimens then underwent computed tomography analysis to evaluate anchor position and trajectories. Target anchor location was determined using a 3-dimensional computed tomography glenoid model, using ImageJ software, with the clockface overlaid onto the glenoid. The 3-o'clock position was set at 0° for reference, with the 3:30, 4:30, and 5:30 anchor positions set at -15°, -45°, and -75°, respectively. One-tailed Results: Inferior anchor (5:30) placement was found to be more accurate in the LD position, while superior anchor (3:30) placement was found to be more accurate in the BC position. Specifically, the LD group did not demonstrate statistically significant deviation from the target ideal (-75°) for the 5:30 anchor. The true deviance for the LD group from the 5:30 target angle was between -78.6° and -58.5° ( Conclusion: Both positioning techniques remain safe and efficacious. The LD position may offer improved inferior anchor placement, and the BC position may offer improved superior anchor placement. Additional studies are warranted to further elucidate the advantages and disadvantages of each position. Clinical Relevance: Knowledge pertaining to the accuracy of anchor placement based on patient positioning and anchor location may aid surgeons in choosing operating positions to potentially optimize anchor placement during arthroscopic anterior shoulder stabilization surgery.