Anterior-inferior (5 o'clock) portal for shoulder arthroscopy.

The present study describes an anterior-inferior portal for arthroscopic shoulder instrumentation at the 5 o'clock position along the glenoid rim. An anterior-inferior portal was established in 14 cadaver shoulders. The portal was created in an inside-to-outside fashion, with the humerus maximally adducted, directing the guide rod as far lateral as possible. Using the described technique, a 5 o'clock portal travels through the subscapularis and lateral to the conjoined tendon. Distance between the portal and the musculocutaneous nerve was 22.9 +/- 4.9 mm (mean +/- SD), and 24.4 +/- 5.7 mm between the portal and the axillary nerve. Previously described portals were either at, or above the 3 o'clock position, resulting in an acute, difficult angle of approach to the glenoid neck. Through a combination of proper arm positioning and rod insertion technique, the 5 o'clock portal can be created safely and is of great potential utility for arthroscopic shoulder stabilization procedures.