Lateral elbow tendinopathy (LET), also known as tennis elbow, affects roughly 1–3% of the general population, particularly individuals engaged in repetitive forearm or gripping activities. The condition is characterized by degenerative changes and fibrosis of the common extensor tendon, primarily the extensor carpi radialis brevis, leading to pain, weakness, and reduced function. Conventional therapies—such as manual therapy, shockwave treatment, or corticosteroid injections—often target inflammation, but the underlying issue in chronic tendinopathy is primarily degenerative rather than inflammatory.
Capacitive–resistive electric transfer (CRet), also known as Tecar therapy, is a form of deep diathermy that delivers radiofrequency currents (300 kHz–1.2 MHz) to produce controlled thermal and non-thermal effects. These include improved blood flow, oxygenation, and cellular proliferation, contributing to tendon repair and pain reduction. Despite its increasing clinical use, few studies have quantified how Tecar energy affects deep elbow structures such as the common extensor tendon and radiohumeral joint capsule, nor have they established the magnitude of current flow required for cellular-level effects.
This study, conducted at the Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya (Barcelona) and the Faculty of Health Sciences, Universidad de Zaragoza (Spain), aimed to analyze the thermal behavior and electric current transmission in both superficial and deep elbow tissues during a 30-minute Tecar (CRet) treatment protocol modeled on clinical practice for chronic elbow tendinopathy. The objective was to determine how each phase of the protocol—varying in mode (capacitive vs resistive) and power level—affects tissue temperature and current flow, thereby identifying which settings best facilitate cellular proliferation and tissue recovery.
This experimental in vitro cadaveric study was designed to evaluate the thermal response and current transmission of a clinical capacitive–resistive electric transfer (CRet) protocol for chronic lateral elbow tendinopathy, using the T-Plus device by Wintecare (Chiasso, Switzerland).
The research was carried out at the Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya (Barcelona) in partnership with the University of Zaragoza. All specimens were provided by the Body Donation Program of UIC, and ethical approval was obtained from the Comitè d’Ètica de Recerca (CER-UIC) under reference CBAS-2019-18.
The study used five cryopreserved full cadavers (three men, two women; mean age 80.6 ± 14.6 years), yielding ten elbows (bilateral). Cadavers were thawed at −16 °C and brought to room temperature for 48 hours before experimentation. None exhibited trauma, surgical scars, or pathology affecting the upper limbs.
A 30-minute Tecar treatment replicating a standard clinical protocol for chronic elbow tendinopathy was applied dynamically by an experienced physiotherapist. The treatment included five consecutive phases using both resistive (RES) and capacitive (CAP) modes:
Dynamic, rhythmic probe movements were performed throughout all applications with constant manual pressure, simulating real clinical handling. The return electrode was placed on the lumbar region of the cadaver to complete the electrical circuit.
Temperature was monitored using Hart Scientific PT25 5628-15 thermocouples inserted under ultrasound guidance (Aloka Prosound C3 with 12L5 linear transducer) into two deep structures:
A Thermocomed digital thermometer measured surface temperature over the lateral elbow. Baseline readings were obtained before treatment, then recorded after each application phase. Electrical impedance was verified with a Fluke 8846A multimeter, ensuring accurate device output. Current flow (A) was computed as average voltage divided by initial impedance for each stage.
All data were analyzed using SPSS v25 (IBM, USA). Distributions were tested for normality with the Shapiro–Wilk test (p > 0.05). Mean, standard deviation, and percentage change from baseline were calculated for all tissue temperature points.
Comparisons between phases were made with the Wilcoxon test, and statistical significance was defined as p < 0.05.
All ten elbows completed the full Tecar protocol successfully, with consistent baseline readings confirming thermal stability prior to treatment. The combination of resistive and capacitive applications produced measurable and statistically significant changes in both temperature and electric current flow across the superficial, common extensor tendon, and radiohumeral capsule regions.
At the end of the 30-minute protocol, temperatures increased in all evaluated tissues relative to baseline:
The detailed evolution of temperature through the five application stages revealed distinct patterns:
Average electric current intensity throughout the treatment remained above 0.03 A—a threshold previously associated with cellular proliferation in vitro. Recorded mean currents per stage were:
These results confirm that even low-power applications—particularly the RES 7 W phase—produced sustained electrical activity sufficient to trigger bioelectrical cellular responses without excessive heat buildup.
Temperature differences between applications were statistically significant for nearly all tissues (p < 0.005), and current flow remained within physiologically relevant ranges throughout. Collectively, the data verified that the 30-minute clinical Tecar protocol induces both controlled deep-tissue heating and steady bioelectric current transmission, depending on each phase’s power and mode configuration.
This cadaveric study demonstrated that a 30-minute clinical Tecar (CRet) treatment protocol using the Wintecare T-Plus device effectively produces both thermal and non-thermal physiological effects in tissues associated with chronic lateral elbow tendinopathy. Across the full sequence of capacitive and resistive applications, the common extensor tendon, radiohumeral joint capsule, and superficial layers exhibited measurable increases in temperature and sustained electric current flow, reflecting controlled energy transfer through multiple tissue depths.
The protocol’s high-power phases (CAP 105–120 VA and RES 90 W) generated marked vasodilatory and hyperthermic effects, promoting increased perfusion and metabolic activity suitable for fibrotic remodeling and chronic stiffness. Meanwhile, the low-power resistive phase (RES 7 W) produced minimal heat but maintained a current intensity around 0.24 A, within the bio-stimulatory range known to enhance cell proliferation and protein synthesis—supporting its role in tissue regeneration. The final CAP 20 VA hypothermic phase effectively lowered tissue temperatures, aligning with the cool-down and drainage objectives of clinical recovery protocols.
These findings confirm that Tecar therapy’s therapeutic versatility arises from its ability to alternate between subthermal electrical activation and controlled hyperthermia, each serving a distinct biological purpose. Clinically, this dual action suggests that non-thermal, low-power resistive applications may be ideal for acute or proliferative phases of tendon rehabilitation, while high-power, thermal phases are better suited for chronic or fibrotic stages, where heat enhances collagen extensibility and local circulation.
Although the absence of perfusion and thermoregulation in cadaveric tissue may exaggerate absolute temperature rises, the study provides the first quantitative verification of energy distribution and current flow during a full, clinically modeled Tecar session for elbow tendinopathy. It establishes a physiological foundation for tailoring treatment phases according to tissue depth and healing stage—reinforcing Tecar therapy’s status as a precise, multimodal intervention capable of combining cellular bioactivation and deep-tissue thermal recovery.
