Sprains are caused when the ligament between the joints is or stretched contracted by an external force, resulting in pain and edema in the local area. Ankle sprains are one of the most commonly observed injuries in clinical practice, presenting with swelling, localized pain, tenderness, and subcutaneous bleeding symptoms [1]. Ankle sprains are usually treated with rest, ice, compression and elevation (RICE) to reduce inflammation, pain, swelling and bleeding. When the pain subsides, plantar flexion is initiated and dorsiflexion exercises are introduced to allow joint mobilization and stretching, ensuring that adduction and abduction is kept to a minimum. Sprains are categorized into 3 grades according to signs and symptoms. Grade 1 and Grade 2 sprains respond well to conservative treatment such as RICE. Conservative treatment is also preferred in Grade 3 sprains when plaster fixation or surgical treatment is offered because these treatments will require long-term recovery and there may be a risk of complications [2].

Untreated sprains, or sprains complicated by other ankle injuries, may result in a chronic relapse of the sprain and joint instability. Early diagnosis and treatment of the sprain will shorten the healing period and prevent weakening of the ankle [3].

It has been reported that treatment of an ankle sprain with acupuncture, Dongsi acupuncture, herbal acupuncture, acupotomy, moxibustion, bloodletting, embedding, Chuna or taping treatment are clinically effective [4].

Chuna treatment is usually applied by the practitioner’s hand, other parts of the body, or ancillary equipment to stimulate the patient’s skin [5]. There are 5 techniques for Chuna treatment; wave, friction, pressure, vibration and osteopathic. Each type of Chuna treatment can aid the recovery of skeletal structures, such as ankle joints, and also help recovery of muscle and ligament injuries, preventing chronic recurrence and instability. In Korea, studies on the Chuna treatment for ankle sprains have been consistently reported [6-11], but these are mostly case reports or studies without controls.

The purpose of this study was to review national and international, randomized controlled trials (RCT) of Chuna treatment for ankle sprains.

A total of 676 studies were retrieved from 6 online databases until October 12, 2017. Of the 676 papers retrieved, PubMed had 23, Cochrane 5, EMBASE 341, CNKI 289, NDSL 13 and OASIS 5. From the 676 studies, 22 duplicates were removed, along with 564 non-related studies, 90 dissertations and, 42 non-RCTs. Of the 48 studies remaining, 1 study was excluded as it did not have the original text, 6 studies excluded due to ankle instability, 4 studies where Chuna belonged to the control group, and 13 studies where Chuna was included as part of combination therapy. This provided a final selection of 24 studies for analysis (Table 1; Fig. 1). Of the 24 studies, 17 [13-29] were in China, 4 [30-33] were in the United States, and 3 [9-11] were published in Korea.

To evaluate the efficacy of Chuna therapy for ankle sprains, 6 online databases were searched and 24 RCT were selected for systematic review.

Of the 24 studies, 17 were published in China, 4 in the United States, and 3 in Korea. In the last 10 years, 20 studies (83%) have been conducted, indicating increasing interest in Chuna treatment for ankle sprains.

In 7 studies (29%), the number of Chuna treatments received was set at 7, which was the most common number of treatments. There were 6 studies (25%) with 7 days of treatment, which was the most common, followed by 5 studies (21%) with treatment completed at 14 days. This suggests that 7 Chuna treatments for ankle sprains every day, or every other day may have a beneficial therapeutic effect.

A total of 18 evaluation indicators were used in the 24 studies. In only 4 studies, comparative, objective indicators such as the degree of swelling, volumetric measurement of the foot, ankle and lower leg (VOFAL), range of motion (ROM), dorsiflexion, and single support time were used to evaluate treatment effects. In most studies, indicators were used to assess the subjective symptoms of the patient making it difficult to completely exclude the possibility of an evaluation error. Therefore, further evaluation using objective indicators will be necessary in the future.

The treatment methods of Chuna were classified into 5 types. In 24 studies, a total of 55 types were used in duplicate, suggesting that more than 1 technique was used for the treatment of ankle sprains. Among the 5 types, the osteopathic technique was used most frequently. However, it was difficult to classify Chuna treatment when the technique was descriptive and not named, and there were limitations in the definition and classification of Chuna treatment, due to the variety of types and techniques. Further studies to more clearly identify Chuna treatment methodology will be needed.

In the control treatment setting, 8 studies used medication and 7 studies used RICE. This showed that comparing basic treatment RICE and Korean medicine drug therapy with Chuna treatment for ankle sprain was a common therapeutic approach.

In the 24 studies, the experimental group and the control group were compared. In each evaluation index of 18 studies, the experimental group showed a statistically significant difference compared to the control group, indicating that Chuna therapy was a beneficial treatment for ankle sprain. In 4 of the remaining 6 studies, there was a significant difference in several evaluation indices. In the other 2 studies, the difference between the control group and the treatment group was not statistically significant in each evaluation index.

There were no reports of adverse reactions in any of the 24 studies suggesting that Chuna therapy was a safe treatment for ankle sprain.

Bias is a systematic error where the findings have deviated from the true value of the outcome or estimation. Understanding bias is important because it can lead to underestimating or overestimating the intervention effect [34]. In this study, the risk of bias assessment was evaluated in 7 areas using Cochrane’s risk of bias (RoB) tool [12] (random sequence generation, allocation concealment, blinding of participant and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting, and other bias). The characteristic of the overall risk assessment of bias was that most of the 24 studies had “unclear risk” items. Only 5 out of 24 studies were describing random sequence generation, and only 6 studies described allocation concealment. The blinding of patient and staff was attempted using sham treatment only in 2 studies, but this proved to be difficult and it was reported that participants and staff became unblinded due to the nature of the Chuna treatment. Selective reporting areas were not mentioned in all studies. Analysis of bias risk showed that in most studies, explanations of research methods to avoid bias were overly concise, or not even described in the random sequence generation, allocation concealment or selective reporting area. These results suggest that researchers require greater awareness of bias when conducting RCT. Thus, in order to demonstrate the efficacy of Chuna treatment for ankle sprain, improved design of clinical studies with low bias will be required by referring to RCT guidelines such as CONSORT 2010 [35]. However, there is a limit to effectively designing a blinded trial due to the interventional nature of Chuna treatment, therefore future research will be needed to improve study designs and controls for Chuna research studies.

In conclusion these results suggest that Chuna treatment is statistically more effective than commonly used treatments such as RICE, internal medicine and external application. However, interpretation of these results is limited as it is difficult to classify the treatment method of Chuna accurately and to evaluate bias.