Background/Purpose: Calcific tendonitis (CT) and noncalcific tendonitis (NCT) of the shoulder is a common cause of shoulder pain and can be unresponsive to conventional therapies. Based on several randomized controlled studies (RCTs), extracorporeal shock wave therapy (ESWT) has been considered an effective alternative treatment. We performed an updated meta-analysis using all available data to analyze the efficacy of ESWT on CT and NCT.

Methods: We searched Medline, Cochrane database, and Google Scholar from inception to May 2012 for human RCTs comparing ESWT versus placebo for shoulder pain due to CT or NCT. We hand searched review articles, manuscripts, and medical journal supplements for additional references. Inclusion criteria were outcome measures of pain (VAS score; low score = less pain), functional assessment (Constant score; high score = better function), and resolution of calcifications (for CT trials). Two reviewers independently determined eligibility, assessed the quality of each trial, and extracted means and variances for these outcome measures. We computed effect sizes for mean change from baseline to 6 months or 3 months if not reported, using Hedges’ g statistic. Effect sizes were pooled using random effects model. We assessed heterogeneity and performed sensitivity analyses removing the outlier trials. Subgroup analyses for CT and NCT, and high energy (HE) and low energy (LE) trials were also performed.

Results: Fifteen trials met inclusion criteria; 11 for CT, 4 for NCT. Overall there were 1221 participants with mean age of 51 years (range 46-56). The proportion of women was 56% (range 39% – 76%). Among all trials, the effect size (ES) for VAS pain favored HE (-2.17; 95%CI [-2.85, -1.49]; I² 51%, p=0.15) and LE showed no effect (-1.15; [-2.63, 0.32]; I² 96%, p=0.00). and the ES for Constant score favored HE (1.77; [1.41, 2.14]; I² 29%, p=0.24) and LE (0.53; [0.16, 0.89]; I² 28%, p=0.24). In CT trials, any level of ESWT improved VAS scores (-2.18; [-3.55, -0.8]; I² 95%, p=0.00) and Constant scores (1.39, [0.81, 1.97]; I² 84%, p=0.00). In NCT trials, any level of ESWT had no effect on VAS scores (-0.15; [-0.57, 0.27]; I² 0%, p=0.35) or Constant scores (0.65; [-0.51, 1.82], I² 75%, p=0.04). Among CT, effect sizes for VAS, Constant scores and resolution of calcifications favored HE over LE (VAS: -0.57; [-1.10,-0.03]; I² 74%, p=0.01; Constant: 0.57; [0.28, 0.87]; I² 56%, p=0.03; Resolution of calcifications: 3.95; [1.55, 10.03]; I² 70%, p <0.01). Sensitivity analysis removing outlier trials yielded comparable results. The overall trial quality was moderate.

Conclusion: High energy shock wave therapy is effective for improving pain and shoulder function in patients with chronic calcific shoulder tendonitis, and can result in complete resolution of calcifications. Limitations include the heterogeneous nature of the included studies. Despite this, ESWT may be an underutilized therapy for a condition that is difficult to manage otherwise.