Safe suture anchor insertion for anterior and posterior hip labral repair

We sought to define bone thickness in relation to the chondral surface at various depths along the anterior and posterior acetabular rim and safe portals for anchor insertion in these regions. Six cadaveric pelvises were mounted on a custom jig. A custom guide was attached to simulate anterolateral (AL), mid-anterior (MA), distal anterolateral (DALA) and posterolateral (PL) arthroscopy portals. Anterior 3 o'clock and 4 o'clock positions were drilled using MA and DALA portals. Posterior 8 o'clock to 11 o'clock positions were drilled using a 1.4-mm drill bit from the PL portal. At depths of 5, 10 and 15 mm, the distance from the drill to the intra and extra-articular surfaces was measured using a custom caliper. Mean distance between drill hole and articular surface for anterior and posterior positions ranged from 1.61 to 2.75mm at 5 mm. The smallest distance between the drill hole and articular surface and the largest width between drill hole and the extra-articular surface were at the 4 o'clock position. No difference between the MA and DALA portals were noted for the anterior positions. For the posterior rim positions, the distance on the articular side remained consistent throughout. For the posterior positions, only the PL portal was utilized. Both the MA or DALA portals can be utilized for safe drilling of the anterior rim positions. The posterior positions can all be safely drilled with a relatively good bone margin using the PL portal, but use of the MA or DALA portals resulted in extra-articular cortical perforation in all cases.