A Cochrane review included 2 studies with a total of 63 subjects. 34 were allocated to corticosteroids and lidocaine, and 29 were allocated to lidocaine alone. Corticosteroid injection with lidocaine was more effective than lidocaine alone on treatment success at four weeks (relative risk 3.15, 95% CI 1.34 to 7.40). In one study the effects of corticosteroid injections lasted up to four months. The number needed to treat to benefit was 3. No adverse events or side effects were reported.
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment) and by imprecise results (few patients and wide confidence intervals).