A 3-arm randomized clinical trial comparing interscalene blockade techniques with local infiltration analgesia for total shoulder arthroplasty

Abstract

The ideal analgesic modality for total shoulder arthroplasty (TSA) remains controversial. We hypothesized that a multimodal analgesic pathway incorporating continuous interscalene blockade (ISB) provides better analgesic efficacy than both single-injection ISB and local infiltration analgesia. This single-center, parallel, unblinded, randomized clinical trialevaluated 129 adults undergoing primary TSA. Patients were allocated to single-injection ISB, continuous ISB, or local infiltration analgesia. The primary outcome was the Overall Benefit of Analgesia Score (range, 0 [best] to 28 [worst]) on postoperative day 1. Additional outcomes included pain scores, opioid consumption, quality of life, and postoperative complications in the first 24 hours, at 3 months, and at 1 year. We analyzed 125 patients (42 with single-injection ISB, 41 with continuous ISB, and 42 with local infiltration analgesia). The Overall Benefit of Analgesia Score was significantly improved in the continuous group (median [25th percentile, 75th percentile], 0 [0, 2]) compared with the single-injection group (2 [1, 4]; P = .002) and local infiltration analgesia group (3 [2, 4]; P < .001). Pain scores were significantly lower in the continuous group compared with the local infiltration analgesia group (P < .001 for all time points)and after 12 hours from ward arrival compared with the single-injection group (median [25th percentile, 75th percentile], 1.0 [0.0, 2.8] vs. 2.5 [0.0, 4.0]; P = .016). After postanesthesia recovery discharge, opioid consumption (oral morphine equivalents) was significantly lower in the continuous group (median [25th percentile, 75th percentile], 7.5 mg [0.0, 25.0 mg]) than in the local infiltration analgesia group (30 mg [15.0, 52.5 mg]; P < .001) and single-injection group (17.6 mg [7.5, 45.5 mg]; P = .010). No differences were found across groups for complications, 3-month outcomes, and 1-year outcomes. Continuous ISB provides superior analgesia compared with single-injection ISB and local infiltration analgesia in the first 24 hours after TSA.