Purpose: Intra-articular (IA) hip cortisone injection is commonly performed as a therapeutic modality in patients with femoral acetabular impingement (FAI). To our knowledge, there is no published data evaluating the clinical benefit of these injections. The purpose of this study was to assess the efficacy of therapeutic IA cortisone injection in these patients.
Methods: At our institution, patients with FAI and labral tear prospectively recorded their numerical rating scale (NRS) pain scores pre-injection, during post-injection anaesthetic phase, and at 14 days post-injection. From this cohort, all patients treated with guided IA cortisone injection, no radiographic evidence of arthritis (Tönnis grade 0 or 1) and pain relief during the anaesthetic phase of the IA injection were included. An absolute change of two points on the NRS score was considered the minimal amount of clinically significant pain relief. Pain scores were compared between the different types of steroid injected.
Results: Fifty-four patients (35 females, 19 males) with a mean age of 32 ± 12 years were included. Average median pre-injection NRS score was 7.0 (range 2.5-10.0), post-injection anaesthetic phase was 1.0 (range 0.0-5.0), and 14 day post-injection was 5.0 (range 0.0-10.0). As a group, NRS scores significantly diminished from post-injection anaesthetic phase to 14 days post-injection (p < 0.001). At 14 days post-injection, only 20 patients (37 %) and at 6 weeks, only 3 patients (6 %) reported a clinically significant decrease in pain. Average duration of pain relief was 9.8 days. There was no difference in pain reduction between steroid preparations.
Conclusion: In patients with symptomatic FAI and labral tear, intra-articular cortisone injection has limited clinical benefit as a therapeutic modality. However, anaesthetic-only IA injections for patients who may be candidates for hip arthroscopy can be a useful diagnostic tool.