Local Anesthesia Prior to Ultrasound-Guided Hip Joint Injections: A Double-Blind Randomized Controlled Trial of Bacteriostatic Saline versus Buffered Lidocaine.

BACKGROUND: Ultrasound (US)-guided hip joint injections are commonly performed for patients with suspected or known intra-articular hip pain. Lidocaine is a well-established local anesthetic used prior to hip joint injections, but it is often associated with discomfort during infiltration. Bacteriostatic saline is an alternative local anesthetic that has been shown to be less painful during infiltration for superficial injections. OBJECTIVE: To compare infiltrative pain and anesthetic efficacy of bacteriostatic saline (0.9% benzyl alcohol) with a standard local anesthetic (buffered 1% lidocaine) used for local anesthesia prior to US-guided intra-articular hip corticosteroid injections. DESIGN: Double-blinded, randomized controlled trial. SETTING: Tertiary care medical center. PARTICIPANTS: Sixty eight patients age 18-80 (mean 54.8) years referred for US-guided intra-articular hip corticosteroid injections. INTERVENTION: Patients were randomized to receive a US-guided hip joint corticosteroid injection using either bacteriostatic saline or buffered 1% lidocaine for preinjection local anesthesia. MAIN OUTCOME MEASURES: Visual Analog Scale (VAS) for pain (0-100) during local anesthetic infiltration as well as during the intra-articular injection. Adverse events were also recorded. RESULTS: There were no significant differences between bacteriostatic saline and buffered lidocaine with respect to pain during local anesthetic infiltration or during the subsequent intra-articular injection. Pain VAS during local anesthetic infiltration was 13.2 (95% confidence interval [CI] 7.8, 18.5) in the bacteriostatic saline group and 14.0 (95% CI 9.4, 18.5) in the buffered 1% lidocaine group (P = .82). Furthermore, pain VAS during the intra-articular injection was 20.7 (95% CI 14.1, 27.3) in the bacteriostatic saline group and 15.7 (95% CI 10.9, 20.3) in the buffered 1% lidocaine group (P = .57). No adverse events occurred. CONCLUSIONS: Bacteriostatic saline is a safe and comparably effective alternative to buffered 1% lidocaine for local anesthesia before US-guided hip joint injections and may be considered for subcutaneous/periarticular anesthesia during similar musculoskeletal procedures.