Intra-Articular Lidocaine Versus Intravenous Sedation for Anterior Shoulder Dislocation Reduction
Benefits in NNT
Similar rates of reduction success rate between the two groups
1 in 6 were helped (adverse events prevented with intra-articular lidocaine compared to intravenous sedation)
Reduced length of stay in the emergency department (by a mean difference of 1.48 hours) with intra-articular lidocaine approach
19.5% lower risk of adverse events
Harms in NNT
SourceLong B, Gottlieb M. intra‐articular lidocaine versus intravenous sedation for anterior shoulder dislocation reduction. Academic Emergency Medicine. Published online January 2023:acem.14653.
Study Population: 12 trials of 630 ED patients ≥15 years undergoing closed reduction for acute anterior shoulder dislocation
Efficacy EndpointsSuccessful reduction, adverse events, emergency department length of stay, pain score, procedure time and patient satisfaction
NarrativeAnterior shoulder dislocation is the most common large joint dislocation managed in the emergency department (ED).1, 2, 3, 4 Several analgesic techniques are available to assist with reduction, including intra-articular lidocaine, nerve blocks, and procedural sedation with intravenous (IV) medications.2, 3, 4 Each technique has distinct advantages (e.g., reduced length of stay with intra-articular lidocaine) and disadvantages (e.g., adverse event such as respiratory depression with procedural sedation). Indeed, several studies have compared these techniques, with a 2014 meta-analysis finding similar efficacy in reduction success rate using either procedural sedation or intra-articular lidocaine with fewer adverse events in the intra-articular lidocaine group.2 Since 2014, additional randomized controlled trials (RCT) have been published, providing further data comparing intra-articular lidocaine and IV sedation.5, 6, 7
The systematic review and meta-analysis summarized here included RCTs comparing intra-articular lidocaine and IV sedation in ED patients with acute anterior shoulder dislocation.8 Participants were ≥15 years of age undergoing closed reduction for treatment of the dislocation. Studies with pediatric populations, posterior dislocations, fracture-dislocations, and settings other than the ED were excluded. The main outcomes included reduction success rate, adverse events, procedure time, and patient satisfaction. Successful reduction was defined as confirmation of relocation in post-reduction imaging. Adverse events were defined by the individual RCT. The meta-analysis identified 12 RCTs published between 1994 to 2020 with 630 patients (327 patients receiving intra-articular lidocaine and 303 patients receiving IV sedation) conducted in the ED setting.8 All patients in the intra-articular lidocaine group received 1% lidocaine, with 10 trials administering 20 mL of 1% lidocaine and 2 trials administering 4 mg/kg (maximum 200 mg). The type of IV sedation medications varied widely across all studies, with a benzodiazepine (diazepam, midazolam) in combination with an opioid (meperidine, morphine, or fentanyl) being the most common sedation regimen used.
There was no difference in reduction success rate nor pain scores between groups. There were, however, reductions in adverse events (RR 0.16; 95% CI, 0.07 to 0.33; number needed to treat: 6; absolute risk reduction: 19.5%), shortened ED length of stay (mean difference: -1.48 hours; 95% CI -2.48 to -0.47), and a shortened procedure time (mean difference: 8 min; 95% CI: 4.42 to 11.57) in the intra-articular lidocaine group. The reported adverse events included agitation and drowsiness associated with intra-articular lidocaine and respiratory depression (including apnea/hypoxia), hypotension, nausea/vomiting, headache, allergic reaction, and thrombophlebitis in patients assigned to the IV sedation group. The systematic review also reported patient satisfaction for each technique. The patient satisfaction rate was lower with intra-articular lidocaine (70.5% vs. 90.4%; RR 0.80: 95% CI, 0.67 to 0.95, moderate certainty). However, this outcome was subject to significant heterogeneity due to variability in the tools used for measuring it.
Of note, a recent network of meta-analysis was published in 2022 that evaluated intra-articular anesthetic injection, intravenous sedation, and peripheral nerve block for shoulder dislocation reduction.9 This meta-analysis found no differences in reduction success rate, adverse respiratory events, or patient satisfaction between the techniques. However, it did identify a longer time for the reduction procedure with intra-articular analgesia compared to IV sedation. As in the previous meta-analysis, intra-articular analgesia resulted in a shorter length of ED stay.8, 9
CaveatsIntra-articular lidocaine and IV sedation can be effective in facilitating the reduction of anterior shoulder dislocations, with distinct advantages and disadvantages for each. This meta-analysis found no significant difference in reduction success rate or pain scores between either option.8 Intra-articular lidocaine was associated with fewer adverse events, shorter ED length of stay, and reduced procedure time, while procedural sedation was associated with higher patient satisfaction.
The presented data have several limitations. There was moderate to high heterogeneity for almost all of the evaluated outcomes except adverse events. The levels of certainty for the measured outcomes ranged from very low to moderate. Both successful reduction and pain score outcomes had low to very low levels of certainty. The significant heterogeneity and lower certainty of evidence limit the applicability of the results. Another important limitation is the variability in the specific agents used for IV sedation. Six RCTs used meperidine/pethidine with a benzodiazepine or propofol, while the other 6 RCTs used propofol, etomidate, ketamine, morphine, fentanyl, midazolam, and diazepam. The specific agent could increase the risk of adverse events, and many of the included studies relied on older regimens, as opposed to current era sedation medications (e.g., propofol, ketamine, and etomidate). Adverse events were also based on individual study definition and may have led to underreporting of some events. Moreover, reduction technique was not standardized, and success rates vary among techniques.3, 10 Neither of these studies compare intra-articular analgesia nor IV sedation with manipulation alone. Modern reduction techniques such as the Cunningham method have demonstrated high rates of success in the hands of trained providers, without concomitant sedation.3, 11 Finally, the efficacy of intra-articular lidocaine is dependent on clinician skill, and the included trials did not provide information concerning clinicians’ training level or whether ultrasound was used.12
Based on the available evidence, we have assigned a color recommendation of Yellow (Equal Efficacy) for the use of intra-articular lidocaine in reduction of anterior shoulder dislocation. It is likely that intra-articular lidocaine injection for anterior shoulder dislocation does not affect the procedure success rate, but it reduces the risk of adverse events and shortens ED length of stay. However, the heterogeneity among trials and suboptimal level of evidence certainty call for larger, more rigorous trials.
The original manuscript was published in Academic Emergency Medicine as part of the partnership between TheNNT.com and AEM.
AuthorBrit Long, MD; Michael Gottlieb, MD
Supervising Editors: Shahriar Zehtabchi, MD
Published/UpdatedDecember 6, 2022
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