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

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.