Which injections are effective for lateral epicondylitis?
EVIDENCE-BASED ANSWER:
Placebo injections actually improve lateral epicondylitis at high rates. No other injections convincingly improve it better than placebo.
Corticosteroid injection is not superior to saline or anesthetic injection (strength of recommendation [SOR] A, systematic review of randomized controlled trials [RCTs]). Platelet-rich plasma (PRP) injection is not superior to saline injection (SOR A, meta-analysis of RCTs).
Botulinum toxin injection, compared to saline injection, modestly improved pain in lateral epicondylitis, but with short-term grip-strength weakness (SOR A, meta-analysis of RCTs). Prolotherapy injection, compared to saline injection, improved pain at 16-week, but not at 8-week, follow-up (SOR B, one small pilot RCT).
Hyaluronic acid injection, compared to saline injection, resulted in a statistically significant pain reduction (6%) but did not achieve the minimum clinically important difference (SOR B, single RCT). Autologous blood injection, compared to saline injection, did not improve disability ratings (SOR B, one small RCT).
Prolotherapy needs further study
A 2008 RCT9 of 20 adults with at least 6 months of lateral epicondylitis received either prolotherapy (1 part 5% sodium morrhuate, 1.5 parts 50% dextrose, 0.5 parts 4% lidocaine, 0.5 parts 0.5% bupivacaine HCl, and 3.5 parts normal saline) injections or 0.9% saline injections at baseline, 4 weeks, and 8 weeks. On a 10-point Likert scale, the prolotherapy group had a lower mean pain score at 16 weeks than the saline injection group (0.5 vs 3.5), but not at 8 weeks (3.3 vs 3.6). This pilot study’s results are limited by its small sample size.
Hyaluronic acid improves pain, but not enough
A 2010 double-blind RCT10 (n = 331) compared hyaluronic acid injection vs saline injection in treatment of lateral epicondylitis in adults with > 3 months of symptoms. Two injections were performed 1 week apart, with follow-up at 30 days and at 1 year after the first injection. VAS score in the hyaluronic acid group, at rest and after grip testing, was significantly different (statistically) than in the placebo group but did not meet criteria for minimum clinically important improvement. Review of the literature showed limited follow-up studies on hyaluronic acid for lateral epicondylitis to confirm this RCT.
Autologous blood has no advantage over placebo
The only RCT of autologous blood compared to saline injections11 included patients with lateral epicondylitis for < 6 months: 10 saline injections vs 9 autologous blood injections. Patient scores on the Disabilities of the Arm, Shoulder, and Hand scale (which measures symptoms from 0 to 100; lower is better) showed no difference but favored the saline injections at 2-month (28 vs 20) and 6-month (20 vs 10) follow-up.
Editor’s takeaway
Limiting the evidence review to studies with a placebo comparator clarifies the lack of effectiveness of lateral epicondylitis injections. Neither corticosteroid, platelet-rich plasma, botulinum toxin, prolotherapy, hyaluronic acid, or autologous blood injections have proven superior to saline or anesthetic injections. However, all injections that contained “placebo” significantly improved lateralepicondylitis.
