Trigger finger (TF) is a condition that causes triggering, snapping, or locking on flexion of the involved finger, with a life- time risk between 2%-3% in the general population. A variety of treatments have been described, but the most effective treatment for this common disorder is still under debate. Recently, extracorporeal shock wave therapy(ESWT) has been advanced as a possible alternative to surgery for the treatment of musculoskeletal disorders in patients recalcitrant to traditional conservative treatment.

However, the effectiveness of ESWT on the treatment of TF is still in lack of evidence. The purpose of this study is to conduct a prospective randomized clinical trial to compare the efficacies of ESWT at two different energy flux density with placebo treatment for the management of TF. The investigators intended to enrolled 60 participants randomly allocated to three groups: low energy ESWT (1500 impulses and 0.006mJ/mm2, 3bar, once per week for 4 weeks), high energy ESWT (1500 impulses and 0.01mJ/mm2, 5.8bar, once per week for 4 weeks) or placebo treatment groups. The effectiveness of the treatment will be assessed using cure rates, a visual analogue scale, the frequency of triggering, the severity of triggering, the functional impact of triggering, and the Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire (qDASH) at 1, 3, and 6 months after treatment. An intention-to-treat analysis will be used in this study. The investigators intend to determine the efficacy of ESWT in the treatment of TF and to find out the ideal energy set-up of ESWT for TF treatment.

Trigger finger (TF) (also known as stenosing tenovaginitis) is characteristic of triggering, snapping, or locking on flexion of the involved metacarpophalangeal joint of finger, with incidence of 2%-3% in the general population and approximately 10% in diabetic patients. A variety of treatments have been described, including activity restriction, stretching exercise, splitting, non-steroid anti-inflammatory drugs, steroid injection, percutaneous or open release. However, none of the above-mentioned treatments is absolutely better than the others. The most effective treatment for this common disorder is still under debate.

Recently, extracorporeal shock wave therapy (ESWT) is getting popular as an alternative to surgery for the treatment of musculoskeletal disorders in patients recalcitrant to traditional conservative treatment. ESWT has been reported to effectively treat orthopedic disorders, such as plantar fasciitis, lateral epicondylitis of the elbow, calcific tendinopathies of the shoulder, and the non-union of long bone fractures. Biologically, ESWT is believed to result in a mechanosensitive feedback between the acoustic impulse and the stimulated cells, involving specific transduction pathways and gene expression. Furthermore, previous studies have shown that increased angiogenetic growth factors with ESWT are causally related to enhanced neovascularization and blood supply in the tendinopathy area of the tendon. ESWT can also induce the repair of the inflamed tissues by tissue regeneration and stimulates nitric oxide synthase, leading to suppression of ongoing inflammation in the soft tissues. However, there are still few clinical evidence on ESWT in treatment of TF in the literature.

One randomized control study reported the efficacy of ESWT in treatment of TF in 2016, and claimed that ESWT was as effective as steroid injection in treatment of TF. However, this clinical study was limited to the lack of control group with placebo treatment, since steroid injection for TF is reported to be with short-term effect and only effective in 57% of patients. Further evidence on the efficacy of ESWT in treatment of TF is needed to be clarified. In addition, the ideal energy set-up and protocol for ESWT are still left to be proven.

Considering the noninvasive advantage and potentially biological effect on the thickening of the flexor tendon and its sheath, the investigators hypothesize ESWT is effective on relieving the symptoms of TF. The purpose of this study is to conduct a prospective randomized clinical trial to compare the efficacies of ESWT at two different energy flux density with placebo treatment for the management of TF. The investigators intended to determine the efficacy of ESWT in the treatment of TF and to find out the ideal energy set-up of ESWT for TF treatment.

Inclusion Criteria:

1. Older than 20 years of age
2. Grade 2~3 trigger finger based on the Quinnell classification

Exclusion Criteria:

1. Previous treatment by physical therapy, local corticosteroid injection, or surgical release for trigger finger before the study
2. The presence of a musculoskeletal disease or previous nerve injuries at the upper extremities
3. Multiple trigger finger; local infection; malignancy; inflammatory arthritis; cardiac arrhythmia or cardiac pacemaker; and pregnancy.

all collected IPD, all IPD that underlie results in a publication

starting 6 months after publication; ending 36 months after publication

With whom: For investigators whose proposed use of the data has been approved by an independent committee

For what type of analysis: For individual participants meta-analysis

For what mechanism: To gain access, data requestor should sign a data access agreement. Data are available for 3 years at third party website.

The patients will be randomized to each group. All participants are blinded to the treatment groups. All of the outcome will be followed by an assistant who is blinded to the allocation.