The low anterior five-o'clock portal during arthroscopic shoulder surgery performed in the beach-chair position.

We evaluated the difficulty, accuracy, and safety of establishing a low anterior 5-o'clock portal for anterior capsulolabral repair in patients positioned in the beach-chair position during shoulder arthroscopy. An initial 5-o'clock portal was created using an inside-out technique as described by Davidson and Tibone. During establishment of the portal, significant force was required to lever the humeral head laterally, and chondral indentations were noted in several specimens. Because of the difficulty noted establishing the 5-o'clock portal using an inside-out technique, we attempted to establish a 5-o'clock anterior portal using an outside-in technique. Seven fresh-frozen cadaveric shoulders underwent shoulder arthroscopy in the beach-chair position. After the establishment of a 3-o'clock portal, a specially constructed guide was used to place a pin at the 5-o'clock position. The distances of the pins from the cephalic vein and the musculocutaneous and axillary nerves were recorded. The bottom (5-o'clock position) and top (3-o'clock position) pins varied from 12 to 20 mm from the musculocutaneous and axillary nerves. The bottom pin was located within 2 mm of the cephalic vein and varied from medial to lateral in different specimens. We do not recommend the use of a 5-o'clock portal using an inside-out or outside-in technique for patients positioned in the beach-chair position during shoulder arthroscopy because of the potential for cephalic vein or articular cartilage injury.