Outside-In Capsulotomy for Intra-articular Hip Access

Background: Arthroscopic treatment of excessive acetabular coverage with pincer morphology or coxa profunda can be challenging. In patients with excessive acetabular coverage with nondistractible hips, an outside-in capsuolotomy can be considered to gain safe and efficient intra-articular access to the hip. Indications: The indications for an outside-in capsulotomy include patients with acetabular retroversion, a lateral center-edge angle >40°, coxa profunda or protrusio, or stiff, older male patients who remain hip preservation candidates. Technique Description: The outside-in capsulotomy is performed once it is recognized that traction on the operative extremity will not provide adequate working space for safe intra-articular access. Traction is taken off the operative extremity, and an anterolateral portal is localized to the 12:00 position on the hip joint with the use of fluoroscopy. The camera is then placed in a juxta-capsular location, and a modified anterior portal is created under direct arthroscopic visualization. We then proceed with extracapsular dissection to identify the indirect head of the rectus. An outside-in capsulotomy is then performed parallel to the indirect head of the rectus, approximately 5 mm distal to its insertion on the acetabular rim. Prior to deep completion of the capsulotomy, the hip joint is flexed to 30° to protect the articular cartilage of the femoral head. Once intra-articular access is obtained, traction can be reapplied, and one can proceed with hip arthroscopy in a standard fashion. Results: This technique decreases the traction time needed, given that the capsulotomy is performed without traction applied. Additionally, the amount of force required for hip distraction is decreased once the capsuolotomy has been completed, through usual sectioning of the iliofemoral ligament. The presented technique is both safe and efficacious, with no published difference in complications as compared to standard inside-out access. A published series of patients with severe pincer morphology and lateral overcoverage who undergo hip arthroscopy with outside-in access demonstrates satisfactory postoperative improvements in patient-reported outcome measures. Discussion/Conclusion: The outside-in capsulotomy provides a means for safe access to the hip joint in otherwise limited or nondistractible hips.