Abstract: We included a total of 20 heterogeneous studies (2012 participants with acute ankle sprains); three of which included more than one comparison. Seventeen trials were conducted in China. All of the studies had a high risk of bias due to lack of blinding. The results may also have been affected by selection bias, particularly as five studies were quasi-randomised controlled trials and 12 studies gave no information on their method of randomisation. Of our three prespecified primary outcomes, only cure rate was reported by the majority of studies. No study reported on patient-reported assessment of function and only one reported on adverse events (in which three participants receiving a control intervention experienced skin problems from over-the-counter Chinese herbal patches). The other 19 studies did not record or report on adverse events. We assessed the quality of evidence for cure rates as very low for all comparisons, which means we are very uncertain about the reliability of any of the estimates. The single study comparing acupuncture treatment with no treatment found acupuncture to be more effective with regard to cure rate at five days (31/31 versus 1/30; RR 20.34, 95% CI 4.27 to 96.68). Acupuncture plus another standard treatment versus that standard treatment alone was tested in eight studies; with cure rate data available for seven. Most of these studies reported higher cure rates in the acupuncture plus another standard treatment group than in the standard treatment alone group. However, while the results of an exploratory meta-analysis of cure rate data from eight trials testing acupuncture versus no acupuncture tended to favour acupuncture, the results were very inconsistent across the studies and the estimated effect was very imprecise (383/396 versus 272/355; RR 1.32, 95% CI 0.95 to 1.84; P value = 0.1; I2 = 98%). Fourteen studies compared acupuncture with a variety of other non-surgical treatments, such as Chinese drug patches, hot and cold water, ice packs, oral Chinese herbal medicine and elastic bandage. Some studies found in favour of acupuncture, some in favour of the other treatment and some found a lack of evidence for a difference between the two interventions under test. The results of an exploratory meta-analysis of cure rate data from 11 trials testing acupuncture versus another non-surgical intervention tended to slightly favour acupuncture, but these were not statistically significant and the data were very heterogeneous (404/509 versus 416/497; RR 1.07, 95% CI 0.94 to 1.22; P value = 0.30; I2 = 92%). The currently available evidence from a very heterogeneous group of randomised and quasi-randomised controlled trials evaluating the effects of acupuncture for the treatment of acute ankle sprains does not provide reliable support for either the effectiveness or safety of acupuncture treatments, alone or in combination with other non-surgical interventions; or in comparison with other non-surgical interventions. Future rigorous randomised clinical trials with larger sample sizes will be necessary to establish robust clinical evidence concerning the effectiveness and safety of acupuncture treatment for acute ankle sprains.

Plain-language summary: Our review includes 20 studies involving 2012 people with ankle sprains. These studies differed from each other in many ways and compared various types of acupuncture with a variety of standard control interventions. Most studies reported only the 'cure rate' - the number of participants who had recovered at a set time. No study reported on patient-reported assessment of function. Only one study reported on adverse events and found skin problems in individuals receiving over-the-counter traditional Chinese herbal patches as a control intervention. Most trials had flaws in the way they were conducted, which makes their results less reliable; for example, most studies failed to ensure participants did not know which intervention they were receiving. One study, which compared acupuncture with no treatment, found more people were cured with acupuncture. Most of the eight studies comparing acupuncture plus another standard treatment versus that standard treatment alone found higher cure rates in the acupuncture group. However, we found that pooling these results did not provide conclusive evidence that acupuncture resulted in a better cure rate. Fourteen studies compared acupuncture with a variety of other non-surgical treatments, such as Chinese herbal patches, hot and cold water, ice packs, Chinese oral herbal medicine and elastic bandages. Some studies found in favour of acupuncture, some in favour of the other treatment and some found a lack of evidence for a difference between the two interventions under test. The pooled results from 11 studies comparing acupuncture versus another non-surgical intervention tended to favour acupuncture, but this evidence was not conclusive. Currently, we are unable to conclude whether or not acupuncture is more effective than other standard methods for the treatment of ankle sprains in adults because of the very low quality of the available evidence. Because the adverse effects of acupuncture treatment were not described in most of the studies, we are also unable to draw any conclusions about the safety of acupuncture. Large, high quality studies of acupuncture for sudden-onset ankle sprains in adults are needed.