Effect of extracorporeal shock wave therapy on pain and function in patients with knee osteoarthritis: a systematic review with meta-analysis and grade recommendations

Objective: To investigate extracorporeal shock wave therapy effect on knee osteoarthritis compared to a sham or kinesiotherapy by a systematic review and meta-analysis of randomized clinical trials.

Data sources: The search was performed in: Cochrane Library, PubMed, PEDro, Web of Science, EMBASE, Scopus, LILACS, and Scielo.

Review methods: We performed the online search until October, 2022. The following terms were used (Osteoarthritis) AND ("knee joint") AND ("Extracorporeal Shockwave Therapy"). Eligibility criteria: (1) randomized clinical trials; (2) effects comparison of shockwave therapy to a sham or kinesiotherapy in individuals with knee osteoarthritis; (3) pain and physical function as outcome variables. Risk of bias assessed using the PEDro scale. PROSPERO registration (CRD42021235597).

Results: We identified 4217 studies, and 12 were included in the qualitative synthesis and the meta-analysis, totaling 403 individuals submitted to the intervention and 331 control individuals. Compared to sham, shockwave was favored in short-term for the function outcome (SMD = -1.93; 95%CI: [-2.77; -1.09]; I² = 83%; P < 0.01). For the pain outcome, the shockwave was favored in the short (MD = -2.05; 95%CI: [-2.59; -1.51]; I² = 84%; P < 0.01), medium (MD = -3.46; 95%CI: [-4.03; -2.89]; I² = 0%; P < 0.01) and long-term (MD = -2.01; 95%CI: [-3.36; -0.65]; I² = 98%; P < 0.01). The association with kinesiotherapy was favored in the short term for the function outcome (SMD = -1.88; 95%CI: [-2.98; -0.78]; I² = 94%; P < 0.01) and favored for the pain outcome in the short (MD = -1.44; 95%CI: [-1.81; -1.07]; I² = 37%; P = 0.14), medium (MD = -1,31; 95%CI: [-1.76; -0,85]; I² = 0%; P = 0.41), and long terms (MD = -1.63; 95%CI: [-1.73; -1.52]; I² = 0%; P = 0.43).

Conclusion: Shockwave therapy may improve functionality in patients with knee osteoarthritis in the short term and pain in all follow-up moments, compared with sham. When associated to kinesiotherapy, it may improve function in the short term and pain in all follow-up time points, although improvement in pain may not be clinically significant.