Outcomes After Diagnostic Hip Injection

Purpose To provide a comprehensive review of outcomes associated with local anesthetic (LA) or LA and corticosteroid (CS) diagnostic hip injections, and how well response predicts subsequent operative success. Methods A systematic review from database (PubMed, Medline, Scopus, Embase) inception to January 2015 for English-language articles reporting primary patient outcomes data was performed, excluding studies with >50% underlying osteoarthritis. Studies were assessed by 2 reviewers who collected pertinent data. Results Seven studies were included, reporting on a total 337 patients undergoing diagnostic hip injection. The mean age was 34.4 years, with 5 studies reporting 94 (35.2%) males and 173 (64.8%) females. One study examined the rate of pain relief with LA (92.5%); 2 CS studies reported relief on a scale from 0% to 100% (no to complete relief), ranging from 61% to 82.3%; and 3 studies used 10-point pain scales, with a CS study noting a pain score of 1.0, an LA study with a score of 3.03, and 1 study using either CS or LA scores of 3 to 5.6. Duration of pain relief was 9.8 (CS) and 2.35 days (LA). By pathology, greatest relief was achieved in acetabular chondral injury (93.3%) and least in cam impingement (81.6%), with clinical and imaging findings being unreliable predictors of relief. One study showed nonresponse to be a strong predictor of negative surgical outcome for femoroacetabular impingement. Conclusions Diagnostic hip injections provide substantial pain relief for patients with various hip pathologies, with limited data to suggest greatest relief for those with chondral injury. Clinical and imaging findings are unreliable predictors of injection response, and nonresponse to injection is a strong negative predictor of surgical outcome. Future research should focus on elucidating differences by underlying pathology and predicting future operative success. Level of Evidence Level IV, systematic review.