The Efficacy of Acupuncture for the Treatment of Snapping Finger in Adults

—Evaluated with a visual analogue scale—

Abstract

Objective: Snapping finger is the result of gliding disorder of the superficial and deep digital flexor tendon and the flexor pollicis longus muscle tendon at the synovial and ligamentous tendon sheath (A1 pulley). In this study, acupuncture was performed at the A1 pulley of the affected finger to determine its effect on pain during snapping and the degree of the snapping phenomenon.
Methods: Acupuncture was performed on 19 fingers of 15 patients. No control group of untreated patients was included in the study, and the same acupuncture treatment was used for all of the patients. The acupuncture needles were inserted in the radial and ulnar sides of the flexor tendon (left inserted for 10 min) at the A1 pulley of the affected finger. Treatment was performed a maximum of 5 times (once every 5 to 7 days). Before and after each treatment, the pain during snapping and the degree of the snapping phenomenon were evaluated using a visual analogue scale (VAS) ranging from 0 mm (no symptoms) to 100 mm (intolerable symptoms). Symptoms before the first treatment and before the fifth treatment were compared to determine the degree of change, taking a 50% improvement as the criterion for judging whether there was an improvement or not, and the relationship between improvement or lack of improvement and the duration of the disorder was examined.
Results: VAS evaluation showed a significant improvement in pain during snapping and the degree of the snapping phenomenon with scores before the first treatment and before the fifth treatment of 57.1±22.2 (mm, mean±SD)→26.0±29.8, 61.2±23.1→26.1±27.6 respectively. VAS evaluation directly after the first treatment also showed a significant improvement in pain and the degree of the snapping phenomenon with scores of 40.8±19.6 and 44.3±23.9 respectively. Furthermore, by the fifth treatment, pain and the snapping phenomenon were observed to have completely disappeared in 4 and 6 fingers respectively. In patients showing an improvement in pain and the snapping phenomenon, the duration of the disorder was significantly short.
Discussion: It is unlikely that acupuncture had an influence on the degeneration and thickening of the ligament tendon sheath. Improvement in the snapping phenomenon is thought to be the result of acupuncture treatment changing regional blood flow and thereby exerting a favorable influence on inflammatory swelling. The alleviation of pain during snapping is believed to be the result of improved flexor tendon gliding as well as the involvement of acupuncture in activation of the pain inhibitory system. Since no control group of untreated patients or sham treatment group were included in the study, the possibility of a placebo effect influencing the results cannot be completely excluded. However, because a difference was observed in the efficacy of the treatment depending on the duration of the disorder, the view is that acupuncture at the impaired A1 pulley could be effective treatment for snapping finger when the main cause is inflammatory swelling of the synovial membrane of the tendon sheath and when the duration of the disorder is short.