Preoperative Hip Injection Response Does Not Reliably Predict 2-Year Postoperative Outcomes After Hip Arthroscopy for Femoroacetabular Impingement

Purpose: To determine whether response to preoperative local anesthetic or corticosteroid intra-articular injections can predict 2-year postoperative outcomes in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS).

Methods: We performed a retrospective analysis of patients undergoing hip arthroscopy for FAIS at a single institution from 2014 to 2020. Patients who underwent preoperative intra-articular hip injections were classified based on injection type (local anesthetic or corticosteroid) and whether they experienced pain relief after injection (responders or nonresponders). Responders were matched 2:1 to nonresponders by age, body mass index, and sex. Patient-reported outcomes (PROs) including the Hip Disability and Osteoarthritis Outcome Score (HOOS), 12-Item Short-Form Health Survey (SF-12) Mental Component Summary score, SF-12 Physical Component Summary score, and visual analog scale pain score were collected preoperatively and 2 years postoperatively. Mean score change and minimal clinically important difference (MCID) achievement were calculated and compared between groups.

Results: The matched cohort included 126 total patients (42 nonresponders and 84 responders; 74.6% female sex; age [mean ± standard deviation], 30.9 ± 9.9 years; body mass index, 24.7 ± 3.7) with no differences in demographic or radiographic hip variables. Both groups showed significant 2-year postoperative score improvements across all PROs, except the SF-12 Mental Component Summary score, which remained unchanged. There was no difference in mean score change or MCID achievement across all PROs between the corticosteroid injection responder and nonresponder groups. In the local anesthetic group, MCID achievement was similar across all PROs, except the visual analog scale pain score, which showed a greater percentage of MCID achievement among local anesthetic nonresponders (89.5%) than in responders (55.0%, P = .03). Significant ceiling effects were most readily apparent within the injection responder group, with greater percentages of patients achieving maximal 2-year postoperative survey scores (HOOS-Activities of Daily Living, 36.9%; HOOS-Pain, 19.0%; HOOS-Quality of Life, 15.5%; and HOOS-Sport, 32.1%).

Conclusions: Response to preoperative injection with either corticosteroid or local anesthetic did not predict 2-year outcomes after hip arthroscopy in patients with FAIS.

Level of evidence: Level III, retrospective matched-cohort study.