Effects of capacitive and resistive electric transfer therapy in patients with painful shoulder impingement syndrome: a comparative study

Background / Purpose

Shoulder impingement syndrome (SIS) is among the most frequent causes of shoulder pain and dysfunction, commonly resulting from subacromial inflammation and rotator cuff tendinopathy. Standard treatments—such as exercise therapy, NSAIDs, or corticosteroid injections—often provide only temporary relief. Capacitive and Resistive Electric Transfer (CARE), also known as Tecar therapy, delivers 448 kHz radiofrequency currents that promote deep tissue heating, enhance blood flow, and stimulate cellular metabolism. This study aimed to evaluate the clinical efficacy of CARE therapy in reducing pain and restoring shoulder function in patients with acute subacromial impingement compared with a sham protocol.

Methods

A retrospective case-control design was used, enrolling 46 patients with Neer stage II–III shoulder impingement syndrome and pain duration under one month. Participants were divided into:

• CARE group (n = 22): Received nine 20-minute sessions over three weeks (three per week) using CareTherapy VR (TecnoBody, Italy) — 10 minutes in capacitive mode (100 W) followed by 10 minutes in resistive mode (200 W).
• Sham group (n = 24): Identical procedure with the device turned off.

Electrodes were placed over the biceps brachii insertion and upper thoracic spine (T1–T9), with conductive cream to ensure even current distribution. No adjunctive therapies were allowed. Outcomes were assessed at baseline (T0), post-treatment (T1), and two-month follow-up (T2) using:

• Pain: Visual Analogue Scale (VAS, 0–10)
• Function: Constant–Murley Scale (CMS, 0–100)
• Disability: Disabilities of the Arm, Shoulder and Hand (DASH, 0–100).

Results

The CARE group experienced a significant and sustained reduction in pain and disability, along with a substantial improvement in shoulder function compared with the sham group.

• Pain (VAS): Decreased from 7.23 ± 1.11 to 2.09 ± 1.51 post-treatment, remaining low at 2.68 ± 0.99 after two months (p < 0.001). The sham group showed no relevant change (6.62 ± 1.06 → 6.58 ± 1.10).
• Function (CMS): Increased from 31.6 ± 11.6 to 66.0 ± 22.1 post-treatment, with sustained results at follow-up (64.9 ± 21.4, p < 0.001).
• Disability (DASH): Improved from 47.7 ± 25.8 to 16.8 ± 12.7, while the sham group remained unchanged (33.5 ± 19.9 → 34.2 ± 19.8).
  Two-way ANOVA confirmed a strong group-by-time interaction (p < 0.001) across all measures, indicating that the observed improvements were due to active Tecar therapy rather than placebo or natural healing.

Discussion

These outcomes demonstrate that Tecar therapy induces rapid and meaningful recovery in shoulder impingement through both thermal and bioelectrical mechanisms. The immediate reduction in pain is likely associated with deep vasodilation, increased oxygen delivery, and the modulation of nociceptive signaling via capacitive–resistive current flow. The concurrent improvement in functional mobility suggests accelerated tissue repair and improved elasticity of periarticular structures. The authors attribute these effects to enhanced ATP production, increased cell membrane permeability, and muscle relaxation, allowing faster resolution of inflammatory congestion. Importantly, improvements persisted two months after the treatment series, reflecting Tecar’s capacity to trigger sustained neuromuscular and metabolic adaptations, not just transient analgesia.

Conclusion

Tecar therapy (CARE) at 448 kHz produced clinically significant, long-lasting pain relief and functional recovery in patients with shoulder impingement syndrome. With just nine sessions, patients experienced over 60% reduction in pain and doubled shoulder mobility, with no adverse effects. These findings support Tecar therapy as a safe, non-invasive, and effective conservative alternative to injections or surgical intervention for subacromial impingement, offering both immediate and sustained therapeutic benefits.