Can intra-articular hip injections predict arthroscopy outcomes for femoroacetabular impingement syndrome? A systematic review.

Background: Femoroacetabular Impingement (FAI) syndrome represents a prevalent aetiology of hip discomfort observed among both adolescent and adult populations. It is initially managed conservatively with oral anti-inflammatories and physiotherapy; some patients proceed to receiving an intra-articular (IA) hip injection, but ultimately, the gold-standard treatment is hip arthroscopy. Study design: Systematic Review. Purpose: To systematically investigate the relationship between response to IA anaesthetic or steroid hip injections and arthroscopy outcomes for FAI syndrome. Methods: A systematic search of PubMed, Medline, CINAHL, SCOPUS, and Cochrane was conducted in line with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Results: Seven studies (Level II-IV) were identified that met our inclusion and exclusion criteria. These studies collectively included 637 patients, demonstrating an average age of 37.5 years (and a range of 14-72 years). Two of the seven studies reported a statistically significant positive correlation between response to IA injections and arthroscopy outcomes. The remaining five studies found that although a positive IA injection response increased the odds of a good outcome post arthroscopy (defined across various studies as a post-operative modified Harris Hip score of >70 points, >79 points or an improvement by 8 or more points), this correlation was not statistically significant. Conclusion: IA hip injections can be a useful prognostic tool, though they are not a consistently reliable predictor of which patients will have good arthroscopic outcomes.