Hip Arthroscopy Outcomes With Respect to Patient Acceptable Symptomatic State and Minimal Clinically Important Difference.PURPOSE
 To determine whether the hip arthroscopy literature to date has shown outcomes consistent with published patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID) estimates.


 All clinical investigations of hip arthroscopy using modified Harris Hip Score (mHHS) and/or Hip Outcome Score (HOS) outcomes with at least 1 year of follow-up were reviewed.  Ninety-one studies (9,746 hips) were included for review.  Eighty-one studies (9,317 hips) contained only primary hip arthroscopies and were the primary focus of this review.  The remaining studies (429 hips) did not exclude patients with prior surgical history and were thus considered separately.  Mean mHHS, HOS-ADL (Activities of Daily Living) and HOS-SS (Sports-Specific) scores were compared with previously published PASS and MCID values.


 After 31 ± 20 months, 5.8% of study populations required revision arthroscopy and 5.5% total hip arthroplasty.  A total of 88%, 25%, and 30% of study populations met PASS for mHHS, HOS-ADL, and HOS-SS, respectively, and 97%, 90%, and 93% met MCID.  On bivariate analysis, increasing age was associated with significantly worse postoperative mHHS (P < .01, R(2) = 0.14), HOS-SS (P = .05, R(2) = 0.12), and rates of reoperation (P = .02, R(2) = 0.08).  Increasing body mass index was associated with significantly worse HOS-ADL (P = .02, R(2) = 0.35) and HOS-SS (P = .03, R(2) = 0.30).


 CONCLUSIONS
 In this meta-analysis of 81 studies of primary hip arthroscopy, we have found that more than 90% of study populations meet MCID standards for the most commonly used patient-reported outcomes measures in hip arthroscopy literature, mHHS and HOS.  Eighty-eight percent meet PASS standards for the mHHS, but PASS standards are far more difficult to achieve for HOS-ADL (25%) and HOS-SS (30%) subscales.  Differences in psychometric properties of the mHHS and HOS likely account for the discrepancies in PASS.


 LEVEL OF EVIDENCE
 Level IV, systematic review of Level I to IV studies.
C