Meaningful Outcomes at Five Year Following Hip Arthroscopy in Patients with Borderline Hip Dysplasia

Abstract

To compare 5-year patient reported outcomes (PROMs) and rates of achieving Minimum Clinical Important Difference (MCID) and Patient Acceptable Symptomatic State (PASS) between patients with and without borderline hip dysplasia (BHD). Data from consecutive patients who underwent primary hip arthroscopy for treatment of FAIS between January 2012 and July 2014 were analyzed. Patients with BHD (LCEA=20-25 degrees) were matched 3:1 by age (+/-1 year) and BMI (+/-5) to control patients with normal acetabular coverage (LCEA=25-40 degrees). Baseline and 5-year postoperative PROMs were collected including: Hip Outcome Score-Activity of Daily Living (HOS-ADL), HOS-Sport Subscale (HOS-SS), and modified-Harris Hip Score (mHHS), along with visual analog scale (VAS) for pain and satisfaction. MCID was calculated using a distribution-based method, while PASS was calculated using an anchor-based method for the study group. PROMs, MCID, and PASS were compared among the two groups. MCID in BHD patient was defined as 10.2, 15.0, and 11.0 for HOS-ADL, HOS-SS, and mHHS, respectively. Threshold scores for achieving PASS in both groups was 91.7, 83.7, and 83.6, respectively. Sixty-five patients with 5-year PROMs were identified with having BHD and were matched to 195 controls. Both BHD and non-BHD patients saw significant increases in score averages over the 5-year period across all 3 PROMS and VAS pain. Comparison of the 5-year PROMS, VAS pain, and VAS satisfaction between the two groups did not demonstrate a statistical difference (p>0.05 for all). There was no difference in the frequency of BHD and non-BHD patients achieving MCID on at least one threshold score (80.0% vs 84.7%; p-value=0.447) and PASS (67.2% vs 69.3%; p-value=0.778). Functional outcome scores of patients with BHD undergoing arthroscopic treatment for FAIS are not significantly different from patients with normal acetabular coverage at 5-year follow-up. Furthermore, patients with BHD achieve meaningful clinical outcomes at the same rate as non-BHD patients.