Patients With Dysplasia Achieve Similar Outcomes and Survivorship to Nondysplastic Patients 10 Years After Hip Arthroscopy for Femoroacetabular Impingement.

Purpose: To determine the long-term outcomes of hip arthroscopy (HA) for femoroacetabular impingement (FAI) in the presence of concomitant lateral rim dysplasia compared with a matched control group.

Methods: Patients undergoing HA between January 2009 and October 2013 with minimum 10-year follow-up were reviewed. The inclusion criteria consisted of patients undergoing HA for FAI with evidence of lateral rim dysplasia (lateral-center edge angle [LCEA] < 25°). Patients with lateral rim dysplasia were matched to patients with an LCEA greater than 30° based on sex, Tönnis grade, and age. Outcomes included survival (avoidance of total hip replacement [THR]), repeated HA, and patient-reported outcomes (PROs). Survivorship was assessed using a Kaplan-Meier curve and log rank test, whereas revision rates between groups were assessed using χ² analysis. Between- and within-group analyses of PROs were conducted using the Mann-Whitney U test and Wilcoxon signed rank test, respectively. The proportion of cases achieving the patient acceptable symptom state was compared between groups using χ² analysis.

Results: This study comprised 46 dysplasia cases and 90 control cases. There was no statistically significant difference between groups in baseline metrics apart from the LCEA (P < .001), Sharp angle (P < .001), and Tönnis angle (P < .001). By 10 years postoperatively, 9% of dysplasia cases and 4% of control cases underwent conversion to THR. There was no statistically significant difference between groups in survival or revision rates. Both groups reported improvements in PROs, and there was no difference between PRO scores at either time point. Excluding cases that underwent THR, 84% and 83% of dysplasia and control cases, respectively, achieved the patient acceptable symptom state.

Conclusions: HA for symptomatic FAI is a successful treatment in cases in which dysplasia is present. Low complication rates, comparable outcomes to cases without lateral rim dysplasia, and a high survivorship rate of 91% at minimum 10-year follow-up are observed. Increasing Tönnis angle preoperatively may increase the risk of THR conversion.

Level of evidence: Level IV, retrospective cohort study.