ePoster #808 - ISHA Annual Scientific Meeting 2016

Does The Hip Capsule Remain Closed Following Hip Arthroscopy With Routine Capsular Plication For Femoroacetabular Impingement?

Alexander Weber, MD, Chicago, IL UNITED STATES
Benjamin Kuhns, MD, Chicago, IL UNITED STATES
Gregory Cvetanovich
Paul Lewis, MD, Chicago, Illinois UNITED STATES
Richard C. Mather, MD, MBA, Durham, NC UNITED STATES
Michael Jonathan Salata, MD, Cleveland, OH UNITED STATES
Shane J. Nho, MD, MS, Chicago, IL UNITED STATES
Gift C. Ukwuani, MD, Chicago, IL UNITED STATES

Rush University Medical Center, Chicago, Illinois, UNITED STATES

FDA Status Not Applicable

Summary: We present MRI data demonstrating the postoperative integrity of the hip capsule in a cohort of patients that underwent capsular closure as a routine component of primary hip arthroscopy for FAI.

Introduction: Capsular defects following hip arthroscopy have now been reported as one of the leading causes necessitating revision surgery for continued pain and/or instability. The purpose of the current study was to examine the integrity of the hip capsule in a cohort of patients that underwent capsular closure as a routine component of primary hip arthroscopy for FAI. Methods: All patients undergoing primary hip arthroscopy for FAI with routine capsular closure between 1/1/2012 and 12/31/2015 were eligible for this study. This cohort was cross-referenced with all hip MRIs ordered by the senior author during this time period to identify patients with postoperative MRIs ordered within 24 months of surgery. Only patients with postoperative MRIs of the surgical hip were selected. Exclusion criteria included patients with a prior hip arthroscopy and those who underwent hip arthroscopy for conditions aside from FAI. Four independent, blinded reviewers evaluated each hip capsule for thickness and the absence or presence of defects. Operative and nonoperative sides were compared using the student t-test. Inter-observer reliability was determined through the intra-class correlation coefficient (ICC) using the two-way mixed model for absolute agreement. Statistical significance was considered for p values < 0.05. Results: During the inclusion period, 1463 patients had hip arthroscopy for FAI with routine capsular closure and 53 (3.6%) underwent a postoperative MRI due to abnormal pain or increased symptoms in the postoperative period. Fourteen of the 53 were excluded due to a prior hip arthroscopy or hip arthroscopy that did not pertain to FAI. The final study cohort included 39 patients (23 female and 16 male) with an average patient age of 31.7 ± 11.4 years and an average body mass index (BMI) was 23.3 ± 2.9 kg/m2. Postoperative MRIs were performed on average 12.5 ± 6.8 months following surgery. The average preoperative alpha angle was 62.2 ± 10.1 degrees, which significantly declined with femoral osteochondroplasty to 32.2 ± 4.3 degrees (p<0.001). The average preoperative LCEA was 39.7 ± 5.9 degrees and this also significantly declined with acetabular rim trimming to 29 ± 4.8 degrees (p<0.001). In the 39 patients examined, there were 3 (7.5%) capsular defects, ICC 0.82. The operative hip capsule was significantly thicker in the zone of capsulotomy and subsequent repair as compared to the unaffected, contralateral hip capsule (5.0 ± 1.2 mm vs. 4.6 ± 1.4 mm; p=0.02), ICC 0.83. Additionally, following capsular repair, males had significantly thicker hip capsules as compared to their female counterparts, on the operative-side (5.4 ± 1.1 mm vs. 4.5 ± 1.2 mm; p=0.02), and the nonoperative-side (4.8 ± 1.6 mm vs. 4.1 ± 0.9 mm; p=0.08). Conclusions: The majority (92.5%) of the repaired hip capsules remained closed at greater than one-year follow-up. The hip capsule adjacent to the capsulotomy and subsequent repair is thickened compared to the same location on the contralateral hip, possibly suggesting a healing response. Aside from gender, patient-related and FAI-related factors do not correlate with capsular thickness nor do they seem to correlate with the propensity to develop a capsular defect.