Evaluating Outcomes and Survivorship of Revision Arthroscopic Surgery for Femoroacetabular Impingement Compared With Matched Primary Cases.

Abstract

Background: The exponential rise in arthroscopy for femoroacetabular impingement (FAI) has led to increased revision surgery rates, although this is often an exclusion criterion from arthroscopy literature.

Purpose: To examine the midterm (minimum 5-year follow-up) outcomes after revision arthroscopic correction of FAI compared with a matched control group of primary surgical cases.

Study design: Cohort study; Level of evidence, 3.

Methods: Prospective outcome data, collected in a consecutive series of patients undergoing revision arthroscopic FAI correction, was retrospectively reviewed. Revision procedures were compared with a matched group of primary surgical cases. Survivorship was defined as the avoidance of total hip replacement (THR) and assessed using a Kaplan-Meier curve with the log-rank test. Regression analysis was conducted to identify predictors of THR conversion. Patient-reported outcomes (PROs) including modified Harris Hip Score (mHHS), University of California, Los Angeles (UCLA), 36-Item Short Form Health Survey (SF36), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) preoperatively and at 5 years postoperatively were compared between the groups. The proportion of patients across groups achieving the minimal clinically important difference (MCID) was compared for each PRO. Finally, a subgroup analysis was performed to compare the outcomes of those who had their index surgery at our clinic and those who had an index procedure elsewhere.

Results: A total of 124 revision cases were compared with 268 primary cases. The most common indication for revision surgery was residual bony deformity. Both groups had high survivorship rates at 5 years (>90%) although revision cases did have a statistically higher conversion to THR than did primary cases (6.5% vs 1.5%; P = .008). Increasing age and revision surgery were identified in regression analysis as predictors for THR conversion. Where THR was avoided, improvements in PROs were observed in both groups (P < .05 for all). Before surgery, revision cases reported lower scores for all PROs. At 5 years, the only statistical difference between the groups was in the distribution of mHHS scores. There were no differences in the rate of MCID achievement between groups.

Conclusion: Residual bony deformity is the most common indication for revision arthroscopy. Revision procedures may have a lower survival than primary cases, although overall survivorship at midterm follow-up is high. Of the revision cases, 17% required further arthroscopy. Where THR is avoided, improvements in pain and function can be expected that are similar to primary surgical cases.