No Difference in Patient-Reported Outcomes for Periacetabular Osteotomy and Hip Arthroscopy With Capsular Plication in the Setting of Borderline Hip Dysplasia: A Propensity-Matched Multicenter Study With Minimum 5-Year Follow-Up

Purpose To compare minimum five-year patient-reported outcomes (PROMs) following hip arthroscopy (HA) and periacetabular osteotomy (PAO) for borderline hip dysplasia (BHD). Methods Hips with a lateral center-edge angle (LCEA) with values 18° ≤ LCEA < 25° that underwent either PAO or HA were selected from two institutions. Exclusion criteria were LCEA < 18°, Tönnis osteoarthritis (OA) grade > 1, prior hip surgeries, active inflammatory disease, Worker’s Compensation, concomitant surgery. Patients were propensity-matched based on age, gender, body-mass index (BMI) and Tönnis grade of OA. PROMs included the modified Harris Hip Score (mHHS), calculation of the minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS) and maximum outcome improvement satisfaction threshold (MOIST). Preoperative radiographic predictors included comparison of the Femoro-Epiphyseal Acetabular Roof (FEAR) Index and ligamentum teres lesions. Results A total of 28 PAO patients were propensity-matched to 49 HA patients. Both groups were similar in terms of mean age, gender, preoperative BMI and LCEA. The PAO group had a higher mean follow-up (95.8 vs. 81.3 months; p = 0.001). The mean FEAR index was significantly lower pre-operatively in the HA group (p < 0.001). Both groups demonstrated similar and significant improvements in mean mHHS from pre-operatively to latest follow-up (p < 0.001). The relative risk for future surgery in the PAO group was 3.49 (p = 0.024), mostly attributed to hardware removal (25%). The revision rate was 3.6% in the PAO group and 8.2% in the HA group (p= 0.65). One patient required revision HA for intraarticular adhesions in the PAO group. Three of the revisions in the HA group required PAO due to persistent pain, and one underwent revision HA alone. One patient in the HA group required conversion to total hip arthroplasty (THA), with none in the PAO group. Conclusion Both PAO and HA with capsular plication provide BHD patients with clinically significant improvements and low revision rates at a minimum of five years postoperatively. Leve of Evidence Level III, retrospective comparative therapeutic trial