Clinical Outcomes of Arthroscopic Femoroacetabular Impingement Surgery for Adolescent Patients With Borderline Hip Dysplasia With a Minimum 5-Year Follow-up.

BACKGROUND: The relationship between borderline developmental dysplasia of the hip (BDDH) and concomitant femoroacetabular impingement (FAI) has not been established in the adolescent population.

PURPOSE: To compare the minimum 5-year outcomes after primary hip arthroscopy in adolescent patients with BDDH and FAI to those with FAI alone.

METHODS: A retrospective review of 122 adolescent patients who underwent primary hip arthroscopy for FAI by the senior author between February 2007 and December 2016 was conducted. Eligible patients who were ≤19 years of age and whose proximal femoral physis had not yet closed and who completed a minimum 5-year follow-up were included. Then, patients with BDDH (lateral center-edge angle [LCEA], 18°-25°) were compared with patients without BDDH (LCEA, ≥25°). Outcome scores, including the modified Harris Hip Score (mHHS), Hip Outcome Score Activities of Daily Living (HOS-ADL), Hip Outcome Score Sport-Specific Subscale (HOS-Sport), Short Form-12 scores, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were prospectively collected.

RESULTS: In total, 23 patients with BDDH and 67 patients without BDDH were included. The mean follow-up times for those with and without BDDH were 6.60 years (range, 5.24-9.73 years) and 8.17 years (range, 6.39-10.08 years), respectively (P = .063). After surgery, the BDDH group showed significantly lower mHHS (median, 96 vs 100; P = .027) and HOS-Sport (97 vs 100; P = .014) values and a higher WOMAC score (4 vs 2; P = .021) compared with the non-BDDH group. However, when looking at the percentage of patients achieving the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) with mHHS, HOS-ADL, and HOS-Sport at 5 years, there were no significant differences between the 2 groups. Only 1 patient (4.3%) required revision hip arthroscopy in the BDDH group, while 8 patients (12%) in the non-BDDH group underwent revision hip arthroscopy. There were no cases that required conversion to periacetabular osteotomy.

CONCLUSION: Hip arthroscopy for FAI in growing adolescents with BDDH is safe and effective and yields equivalent achievement in PASS and MCID with clinical outcomes when compared to adolescents without BDDH.

STUDY DESIGN: Cohort study; Level of evidence, 3.