ABSTRACT
BACKGROUND: Frozen shoulder is not an uncommon disease, which is associated with chronic pain and joint movement limitation. However, there are numerous devices to assist in the treatment of shoulder pain, but their efficacy has not been proven and their use remains immensely controversial. Therefore, a randomized clinical study was conducted to determine the effectiveness of a low-frequency stimulator for the treatment of frozen shoulder. METHODS: A randomized clinical trial was carried out on 40 patients with frozen shoulder, with 40 patients assigned to two groups; a control treatment group (group C, n = 20) and a low frequency stimulator application group (group T, n = 20). Both groups were given a routine treatment modality, such as trigger point injection, intramuscular stimulation or suprascapular nerve block etc. The level of the shoulder pain was evaluated using a 100mm VAS (visual analog scale) at each visit, with the limitation in the range of motion simultaneously evaluated. RESULTS: All the subjects improved after treatment, with the VAS scores after termination of treatment showed a statistically significant reduction (P < 0.05). However, there was no significant difference between the two groups. One month after termination of 5 cycles of treatment, group T maintained their improved state, whereas the pain in some of those in group C reemerged, which also showed a statistically significant difference (P < 0.05). The limitation in the range of motion improved, with most subjects able to resume daily activity. CONCLUSIONS: Although the low frequency stimulation provided no more pain relief than routine treatment, the effect was significantly prolonged. From this result, low frequency stimulation can be considered to aide the therapeutic effect of classical frozen shoulder therapy.