Anatomic Evaluation of the Interportal Capsulotomy Made with the Modified Anterior Portal versus Standard Anterior Portal: Comparable Utility with Decreased Capsule Morbidity.

PURPOSE

To identify potential differences in interportal capsulotomy size and cross-sectional area (CSA) using the anterolateral portal (ALP) and either the: (i) standard anterior portal (SAP) or (ii) modified anterior portal (MAP).

MATERIALS AND METHODS

Ten cadaveric hemi pelvis specimens were included. A standard arthroscopic ALP was created. Hips were randomized to SAP (n=5) or MAP (n=5) groups. The spinal needle was placed at the center of the anterior triangle or directly adjacent to the ALP in the SAP and MAP groups, respectively. A capsulotomy was created by inserting the knife through the SAP or MAP. The length and width of each capsulotomy was measured using digital calipers under direct visualization. The CSA and length of the capsulotomy as a percentage of total iliofemoral ligament (IFL) side-to-side width were calculated.

RESULTS

There were no differences in mean cadaveric age, weight or IFL dimensions between the groups. Capsulotomy CSA was significantly larger in the SAP group compared with the MAP group (SAP 2.16±0.64 cm vs. MAP 0.65±0.17 cm, =0.008). Capsulotomy length as a percentage of total IFL width was significantly longer in the SAP group compared with the MAP group (SAP 74.2±14.1% vs. MAP 32.4±3.7%, =0.008).

CONCLUSION

The CSA of the capsulotomy and the percentage of the total IFL width disrupted are significantly smaller when the interportal capsulotomy is performed between the ALP and MAP portals, compared to the one created between the ALP and SAP. Surgeons should be aware of this fact when performing hip arthroscopy.