Substitution of liposomal bupivacaine for lidocaine reduces incidence of injection-emergent adverse events after intraarticular therapies for knee osteoarthritis: a prospective cohort study.

Background: Local anesthetics as a part of intraarticular therapies (IATs) are widely used for treating knee osteoarthritis (KOA). Whether the substitution of liposomal bupivacaine (LB) for lidocaine is safe and effective in reducing the incidence of injection-emergent adverse events (AEs) after IATs remains unclear.

Methods: We recruited outpatients who had a clinical diagnosis of KOA and decided to receive IATs from November 2023 to April 2024. The type of IATs (glucocorticoids, platelet-rich plasma, and hyaluronic acid) for each participant was decided by the preference of patients after consulting with his or her treating physicians. Using lidocaine or LB as local anesthetics was determined by enrollment timing due to considerations of safety. The primary outcome was injection-emergent AEs after IATs. Secondary outcome measures included the Visual Analog Scale (VAS) pain scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale score.

Results: In this study, 123 and 103 patients, respectively, received lidocaine and LB according to their enrollment date. Compared with lidocaine, using LB yielded a reduced incidence of AEs in the overall 2 weeks (LB vs. lidocaine, 30.1% vs. 45.5%, P = 0.018) and week 1 (LB vs. lidocaine, 23.3% vs. 39.8%, P = 0.008). After adjusting for sex, baseline body mass index, age, baseline WOMAC pain subscale score, and K-L grade, the substitution of LB for lidocaine was significantly associated with the reduced incidence of AEs in 2 weeks (OR, 0.484; 95% CI, 0.274-0.853; P = 0.012). In the initial 3 days, the LB groups reported better outcomes in terms of VAS pain score (change from baseline of VAS pain, LB vs. lidocaine, day 1 -8.3 ± 8.9 vs. -1.9 ± 9.3, P < 0.001; day 2 -20.6 ± 16.1 vs. -13.7 ± 19.4, P = 0.005; day 3 -22.3 ± 18.5 vs. -16.3 ± 19.3, P = 0.020). The changes from the baseline of the WOMAC pain subscale at day 14 were similar between the two groups (LB vs. lidocaine, -32.2 ± 11.7 vs. -29.4 ± 11.3, P = 0.073).

Conclusion: With the substitution of LB for lidocaine, patients might have reported reduced incidence of AEs, mainly derived from the superiority in week 1. The substitution of LB for lidocaine was safe in different scenarios of IATs, and future randomized clinical trials were warranted by the current study.