Clinical Outcomes Comparing Capsular Repair vs. No Repair Following Hip Arthroscopy: A Prospective, Randomized, Control Study

OBJECTIVES: As hip arthroscopy procedures become more common there is increasing concern of iatrogenic instability from excessive capsulotomy during surgery. As a result, greater attention is being focused preserving hip capsule integrity following surgery. To date, there are no large scale prospective blinded studies that address whether capsular closure has any detrimental effect on outcomes. Our goal is to evaluate outcomes in patients undergoing interportal capsulotomy repair compared to outcomes when not repairing the capsule. The purpose of this study is to demonstrate a clinical/functional difference at 1 & 2 year follow up between patients who undergo capsular repair vs no repair following hip arthroscopy. Our hypothesis is that restoration of normal capsular anatomy with interportal repair will achieve similar clinical outcomes as the “no repair” group without functional deficits from over-constraint. METHODS: Adult patients were recruited from November 2013 to July 2015 who were scheduled to undergo hip arthroscopy for femoral acetabular. Subjects were randomized into either the capsular repair (CR) or no repair (NR) groups. Standard AP/Dunn view radiographs were evaluated and alpha angle (AA) /center-edge (CEA) angle measurements were performed for all patients preoperatively. All patients underwent standard hip arthroscopy with labral repair +/- CAM/pincer lesion resection. Primary clinical outcomes were measured via the Hip Outcome Score Activities of Daily Living (HOS-ADL) and Sport-Specific (HOS-SS) subscales at 3 months, 6 months and 1 year. Secondary outcome measures included the modified Harris Hip Score (mHHS), visual analog scale (VAS), the international hip outcome tool (iHOT-12), and the Veterans RAND 12 Item Health Survey (VR-12) scores. RESULTS: A total of 56 patients were included in this study (30 male, 26 females) with a mean age of 33 years. Follow up was available for 49 patients at 6 months, 41 patients at 1 year and 26 patients at 2 years. Radiographic measurements were similar between groups. The remainder of the demographic data and baseline functional scores were not significantly different between CR and NR groups apart from height, which was larger in the no-repair group by 3.8 inches (p = .003). The HOS-ADL score significantly improved over time in both groups from 56.7 +/- 18.2 to 86.7 +/- 19 in the CR group (p < .0001) and from 66 +/- 19.2 to 86.9 +/- 23.2 in the NR group (p < .0001) at 1 year. The HOS-SS score significantly improved over time in both groups from 31.7 +/- 21.5 to 72.7 +/- 28.9 in the CR group (p < .0001) and from 38.9 +/- 25.6 to 79.3 +/- 35.8 in the NR group (p < .0001) at 1 year. However, there were no significant differences in functional scores (HOS-ADL, HOS-Sports subscale, iHOT-12, Modified HHS, VAS, VR-12 Physical Score and the VR-12 mental score) between groups at 6 months, 1 year and 2 years. Functional improvement was noted for all secondary outcome measures, however there was no significant difference between the groups at any time point. Pearson correlation coefficients identified a negative relationship between alpha angle and HOS-SS (-0.32, p = .053) suggesting that larger alpha angle may be associated with inferior functional outcome. CONCLUSION: Capsular closure appears to have no detrimental effect on functional outcome scores compared to patients who do not have capsular closure following hip arthroscopy. We recommend restoration of native anatomy if possible when performing procedures that alter it for exposure.