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.