Summary

Intra-articular gadolinium for magnetic resonance arthrogram administered concurrently with a diagnostic intra-articular anesthetic injection can result in a false negative response to the diagnostic injection, but is not a negative predictor of short-term surgical outcomes after hip arthroscopy.

Abstract

Introduction

Magnetic resonance arthrography (MRA) with intra-articular gadolinium and diagnostic intra-articular anesthetic injections (DIAI) are important tools in the evaluation of young patients with hip pathology and are often performed concurrently. However, some authors have questioned whether concurrent gadolinium administration can lead to false negative DIAI due to post-arthrography pain.

Methods

Patients receiving a series of two diagnostic intra-articular hip injections with anesthetic, the first with gadolinium for concurrent MRA and the second without gadolinium, were retrospectively identified. Pain response to diagnostic injection, injectate volume, local anesthetic volume, inclusion of corticosteroids, and method of injection were compared between injections. False negative injection was defined as <50% pain relief with concurrent gadolinium, but > or =50% pain relief with subsequent anesthetic injection without gadolinium. False negative injections in patients that ultimately underwent primary hip arthroscopy were identified from this cohort and matched in a 3:1 ratio to a control cohort to compare post-operative single assessment numerical evaluation (SANE) scores.

Results

Forty-three patients underwent a series of anesthetic injections with and without gadolinium and met inclusion and exclusion criteria. Pain response was significantly different in injections performed with and without gadolinium (18% vs. 81%; p<0.001). There were significant differences in total injectate volume, local anesthetic volume, corticosteroid use, and method of injection between injections, but these variables were not correlated with pain response based on Spearman's correlation tests. Fifteen patients had false negative responses to injection with gadolinium and were matched in a 3:1 ratio to a control cohort. There was no difference in post-operative SANE scores between the gadolinium-sensitive and control groups (81.6 vs. 80.0, p>0.05) collected at an average one year post-operatively.

Conclusion

Concurrent administration of intra-articular gadolinium with DIAI may result in a false negative response to anesthetic. Additionally, in patients with initial false negative DIAI with gadolinium followed by response to a second injection without gadolinium, short-term post-operative outcomes after hip arthroscopy are similar to a matched cohort.