A Comparison of Clinical Outcomes After Unilateral or Bilateral Hip Arthroscopic Surgery: Age- and Sex-Matched Cohort Study

Abstract

Background: A significant number of patients undergoing hip arthroscopic surgery for femoroacetabular impingement (FAI) have bilateral deformities and may require surgery for both hips. Purpose: To compare outcomes between patients who underwent bilateral hip arthroscopic surgery to a matched cohort of patients who underwent unilateral hip arthroscopic surgery. Study Design: Cohort study; Level of evidence, 3. Methods: A consecutive series of patients who underwent primary hip arthroscopic surgery for FAI by a single fellowship-trained surgeon from January 2012 to January 2014 and had a minimum follow-up of 2 years were evaluated. Patients who underwent staged bilateral hip arthroscopic surgery were identified and matched 1:2 to patients who underwent unilateral hip arthroscopic surgery based on age, sex, and body mass index (BMI). Demographic, preoperative, and postoperative variables were compared between the groups. Results: Forty-three patients in the bilateral group were matched with 86 patients in the unilateral group based on sex (24 female [56%] vs 48 female [56%], respectively; P > .99), age (28.6 ± 10.8 years vs 28.9 ± 10.8 years, respectively; P = .88), and BMI (24.8 ± 5.8 kg/m2 vs 24.8 ± 4.0 kg/m2, respectively; P = .98). There were no significant preoperative demographic or radiographic differences between the groups. Both groups demonstrated significant preoperative to postoperative improvements in the Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), and modified Harris Hip Score (mHHS) (P < .0001 for all). When compared with patients in the unilateral group, patients who underwent bilateral hip arthroscopic surgery had less improvement in mHHS and pain scores. Sixty-five (76%) patients in the unilateral group achieved the minimum clinically important difference (MCID) for the mHHS compared with 21 (49%) in the bilateral group (P = .03), while 64 (74%) patients achieved the patient acceptable symptomatic state (PASS) for the mHHS compared with 22 (51%) in the bilateral group (P = .02). Patients in the bilateral group with greater than 10 months between surgical procedures had lower postoperative HOS-ADL scores (P = .04) and lower improvement in pain and HOS-SS scores (P < .0001 and P = .05, respectively). Conclusion: Patients who underwent unilateral and bilateral hip arthroscopic surgery for FAI had improved functional outcomes after 2 years. However, patients who underwent bilateral hip arthroscopic surgery had less improvement in their mHHS and pain scores compared with those who underwent unilateral hip arthroscopic surgery but no differences in HOS-ADL, HOS-SS, or satisfaction scores. Patients in the bilateral group with longer than 10 months between surgical procedures had lower outcome scores than patients who underwent their second surgical procedure within 10 months of their primary surgery.