EVIDENCE SUMMARY
Neither corticosteroids nor platelet-rich plasma are superior to placebo
A 2014 systematic review of RCTs of nonsurgical treatments for lateral epicondylitis identified 4 studies comparing corticosteroid injections to saline or anesthetic injections.1 In the first study, investigators followed 64 patients for 6 months. Both groups significantly improved from baseline, but there were no differences in pain or function at 1 or 6 months. Skin discoloration occurred in 2 patients who received lidocaine injection and 1 who received dexamethasone.2
In a second RCT of patients with symptoms for > 4 weeks, 39 participants were randomized to either betamethasone/bupivacaine or bupivacaine-only injections. In-person follow-up occurred at 4 and 8 weeks and telephone follow-up at 6 months. Both groups statistically improved from baseline to 6 months. No differences were seen between groups in pain or functional improvement at 4, 8, or 26 weeks, but the betamethasone group showed statistically greater improvement on the Visual Analog Scale (VAS) from 8 weeks to the final 6-month telephone follow-up. No functional assessments were reported at 6 months.3
The third RCT of 165 patients with lateral epicondylitis for > 6 weeks evaluated 4 intervention groups: corticosteroid injection with/without physiotherapy and placebo (small-volume saline) injection with/without physiotherapy. At the end of 1 year, the corticosteroid injection groups had less complete recovery (83% vs 96%; relative risk [RR] = 0.86; 99% CI, 0.75-0.99) and more recurrences (54% vs 12%; RR = 0.23; 99% CI, 0.10-0.51) than the placebo groups.4
The fourth RCT randomized 120 patients to either 2 mL lidocaine or 1 mL lidocaine plus 1 mL of triamcinolone. At 1-year follow-up, 57 of 60 lidocaine-injected patients had an excellent recovery and 56 of 60 triamcinolone plus lidocaine patients had an excellent recovery.5
Platelet-rich plasma. A meta-analysis6 of RCTs of PRP vs saline injections included 5 trials and 276 patients with a mean age of 48 years; duration of follow-up was 2 to 12 months. No significant differences were found between the groups for pain score—measured by VAS or the Patient-Rated Tennis Elbow Evaluation (PRTEE)—(standardized mean difference [SMD] = –0.51; 95% CI, –1.32 to –0.30) nor for functional score (SMD = 0.07; 95% CI, –0.46 to 0.33). Two of the trials reported adverse reactions of pain around the injection site: 16% to 20% in the PRP group vs 8% to 15% in the saline group.
Corticosteroids and PRP. A 2013 3-armed RCT7 (n = 60) compared 1-time injections of PRP, corticosteroid, and saline for treatment of lateral epicondylitis. Pain was evaluated at 1 and 3 months using the PRTEE. Compared to saline, corticosteroid showed a statistically significant, but not a minimum clinically important, reduction (8% greater improvement) at 1 month but not at 3 months. PRP pain reduction at both 1 and 3 months was not significantly different from placebo. Importantly, a small sample size combined with a high dropout rate (> 70%) limit validity of this study.
Botulinum toxin shows modest pain improvement, but …
A 2017 meta-analysis8 of 4 RCTs (n = 278) compared the effectiveness of botulinum toxin vs saline injection and other nonsurgical treatments for lateral epicondylitis. The studies compared the mean differences in pain relief and hand grip strength in adult patients with lateral epicondylitis symptoms for at least 3 months. Compared with saline injection, botulinum toxin injection significantly reduced pain to a small or medium SMD, at 2 to 4 weeks post injection (SMD = –0.73; 95% CI, –1.29 to –0.17); 8 to 12 weeks post injection (SMD = –0.45; 95% CI, –0.74 to –0.15); and 16+ weeks post injection (SMD = –0.54; 95% CI, –0.98 to –0.11). Harm from botulinum toxin was greater than from saline or corticosteroid, with a significant reduction in grip strength at 2 to 4 weeks (SMD = –0.33; 95% CI, –0.59 to –0.08).
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