Pain management in shoulder arthroplasty: a systematic review and network meta-analysis of randomized controlled trials

Background: Postoperative pain management after total shoulder arthroplasty (TSA) can be challenging. Given the variety of pain management options available, the purpose of this investigation was to systematically review the literature for randomized controlled trials reporting on pain control after shoulder arthroplasty. We sought to determine which modalities are most effective in managing postoperative pain and reducing postoperative opioid use.

Methods: A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. PubMed, Scopus, and the Cochrane Central Register of Controlled Trials were searched for Level I-II randomized controlled trials that compared interventions for postoperative pain control after TSA. Pain control measures included nerve blocks and nerve block adjuncts, local injections, patient-controlled analgesia, oral medications, and other modalities. The 2 primary outcome measures were pain level measured on a 0-10 visual analog scale and opioid use. The risk of study bias and methodologic quality were analyzed using The Cochrane Collaboration's Risk of Bias 2 (RoB 2) tool. Network meta-analyses were performed for visual analog scale pain scores at postsurgical time points and opioid use using a frequentist approach and random-effects model, with heterogeneity quantified using the I² statistic. Treatments were ranked using the P score, and statistical significance was set at P < .05.

Results: The initial search yielded 2391 articles (695 duplicates, 1696 screened, 53 undergoing full-text review). Eighteen articles (1358 shoulders; 51% female patients; mean age range, 65-73.7 years; 4 studies with low risk of bias, 12 with some risk, and 2 with high risk) were included and analyzed. At 4 and 8 hours postoperatively, patients receiving local liposomal bupivacaine (LB) injection (P < .001 for 4 and 8 hours) or local ropivacaine injection (P < .001 for 4 hours and P = .019 for 8 hours) had significantly more pain compared with patients who received either a continuous interscalene block (cISB) or single-shot interscalene block (ssISB). No differences in opioid use (at P < .05) were detected between modalities. The P scores of treatments demonstrated that ssISBs were most favorable at time points < 24 hours, whereas pain at 24 and 48 hours after surgery was best managed with cISBs or a combination of an ssISB with a local LB injection.

Conclusion: Interscalene blocks are superior to local injections alone at managing pain after TSA. Single-shot interscalene blocks are optimal for reducing early postoperative pain (< 24 hours), whereas pain at 24-48 hours after surgery may be best managed with cISBs or a combination of an ssISB with a local LB injection.