Gadolinium injected concurrently with anesthetic can result in false-negative diagnostic intra-articular hip injections.

Purpose: The purpose of this paper was to evaluate the response to intra-articular hip injections with and without concurrent gadolinium administration. Our secondary outcome was to compare post-operative outcomes between patients with an initial false-negative gadolinium-containing injection and a matched control group.

Methods: Patients receiving a series of two hip diagnostic intra-articular injections (DIAI), the first with gadolinium for concurrent MRA and the second without gadolinium, were retrospectively identified. Pain response to DIAI, 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 ≥ 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 short-term post-operative single assessment numerical evaluation (SANE) outcomes.

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. Fifteen patients with false-negative responses to injection underwent primary hip arthroscopy and were matched in a 3:1 ratio to a control cohort. There was no difference in short-term post-operative SANE scores between the gadolinium-sensitive and control groups (81.6 vs. 80.0, n.s.).

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, short-term post-operative outcomes after hip arthroscopy are similar to a matched cohort.

Level Of Evidence: Level III.