Outcomes of Capsular Plication as Part of Hip Arthroscopic Management for Surgically Identified Microinstability Are Comparable to Outcomes in Matched Controls

PURPOSE: To compare 2-year minimum outcomes of hip arthroscopic management with capsular plication in patients with microinstability with propensity-matched controls. METHODS: We searched primary hip arthroscopies undertaken between August 2009 and December 2020 from a single-surgeon database, excluding those with lateral center-edge angle <18°, for those with intraoperatively confirmed microinstability: having either increased ease of distraction under anesthesia, an isolated straight anterior labral tear, inside-out chondral lesion, or lateral Seldes 2 or 3 labral tear without cam or pincer morphology. Patient-reported outcome scores were prospectively collected at 6-month, 12-month, and minimum 2-year follow-up: International Hip Outcome Tool 12-Item, Non-Arthritic Hip, and Hip Disability and Osteoarthritis Outcome Score. Scores and rates of revision/reoperation or conversion to hip arthroplasty were compared with control hips matched for gender, age, lateral center-edge angle, and degree of chondral defect. RESULTS: Scores for 208 microinstability hips (aged 30.9 ± 10.4 years, 201 women) were comparable to 208 controls (aged 30.6 ±10.5 years, 200 women); only the Hip Disability and Osteoarthritis Outcome Score-Sports subscale showed a minor between-group difference in the trajectory of change in scores from preoperative to 2-year minimum follow-up (P = .045 for time point × group interaction), with shorter follow-up duration for microinstability group (2.2 ± 0.4 years) versus control group (2.7 ± 1.9 years; P < .001). Proportions attaining minimal clinically important difference, 0.5× preoperative standard deviation (70.6%-84.8%), patient acceptable symptom state (54.7%-59.7%), and substantial clinical benefit (48.3%-62.3%) did not differ between groups for any scores (all P > .1). Surgery occurred 2.61 years later in the microinstability group than in the control group (P < .001). Annual rates of revision/reoperative procedures and conversion to arthroplasty did not differ between groups; the combined-group rates were 1.65%/year and 0.27%/year, respectively, after 6.2 ± 2.9 years (mean ± standard deviation) of follow-up. CONCLUSIONS: Patients with surgically identified microinstability can be successfully managed with capsular plication as part of hip arthroscopy, achieving surgical and patient-reported outcomes similar to those of other arthroscopy patients of comparable sex, age, and surgical characteristics. LEVEL OF EVIDENCE: Level III, case-control study.