Since the early 1990s, extracorporeal shock wave therapy (ESWT) has been used for the treatment of non-union or delayed union of fractures. During ESWT, a characteristic shock wave is generated outside the body. The energy is transmitted into the body and is believed to ease pain and speed up the healing process. This systematic review aims at summarising the evidence concerning the efficacy and safety of ESWT for the treatment of non-union or delayed union of fractures.

Overall, we identified ten studies through a systematic literature search that was complemented by a hand search. Of the ten studies, one was a randomised controlled trial (RCT) and the remaining nine were prospective, uncontrolled case-series. In total, 1,469 patients with delayed union or non-union of fractures were treated across all studies, 1,427 of whom received ESWT and the remaining 42 were treated surgically.

In terms of efficacy, we included one RCT and reported the following outcomes: union rate, time to fracture union, function, pain and quality of life. Regarding safety, we included one RCT and six out of nine prospective case-series, in which safety outcomes were reported.

In total, there is a lack of evidence concerning ESWT for the treatment of non-union or delayed union of fractures, particularly in terms of efficacy. It is recommended to conduct prospective, (randomised) controlled trials comparing ESWT with placebo (e.g. sham-ESWT) and to standardise definitions and treatment protocols. Furthermore the inclusion of homogeneous patient populations is recommended, as well as taking into account co-morbidities and assessing patient-relevant outcomes.