TENS was employed as a non-invasive pain management technique in this study, utilizing the Intellect Advanced device manufactured by Chattanooga Group. Electrodes were strategically placed over the affected shoulder, ensuring coverage of the most painful areas as well as relevant nerve pathways to maximize the analgesic effect. A symmetric biphasic waveform was selected, with a frequency of 100 Hz and a pulse duration of 100 microseconds. The intensity of the stimulation was adjusted according to the patient's tolerance, typically aiming for a strong, yet comfortable tingling sensation.

In the experimental group, in addition to conventional TENS and hotpack, TECAR therapy was also applied three times per week for a total of six sessions. TECAR therapy was administered using the BTL-6000 TR-Therapy PRO device by an experienced physiotherapist.The device emitted energy at a frequency of approximately 500 kHz and used three types of electrodes: active, neutral, and static application electrodes. The active electrodes were of two types, capacitive and resistive, and were applied directly during treatment. The neutral electrode functioned as a reference and was positioned beneath the patient's body, close to the treatment site. Each patient was seated in a comfortable position with the affected shoulder exposed, ensuring adequate support and stability throughout the treatment session. Each session lasted approximately 15 minutes.

All patients were administered a therapeutic exercise program that included passive, active-assisted, and active range of motion exercises, stretching, strengthening, and mobilization exercises based on their level of movement restriction and pain intensity for 5 sessions per week for 2 weeks under the supervision of an experienced physiotherapist.

The Visual Analog Scale (VAS) was employed to evaluate pain intensity in patients. This scale features a 10 cm horizontal line, where one end represents "no pain" (0) and the other represents "worst imaginable pain" (10). Patients were instructed to place a mark on the line that best reflected their current pain level. The distance from the "no pain" end to the patient's mark was measured in centimeters and recorded as the VAS score, providing a numeric representation of their pain intensity

The Shoulder Pain and Disability Index (SPADI) was used to evaluate both pain and functional limitations related to shoulder disorders. SPADI is a patient-reported outcome measure consisting of 13 items, divided into two subscales: pain (5 items) and disability (8 items). Each item is rated on a numerical rating scale (0:no pain or difficulty to 10:worst pain imaginable or extreme difficulty). The scores for each subscale are averaged to create a total score, expressed as a percentage, with higher scores reflecting greater pain and disability. SPADI is widely recognized and validated for assessing shoulder-related pain and functional impairment in both clinical practice and research

The ultrasonographic assessments were performed using a 5-12 MHz linear array transducer by an expertized physician blinded to the groups. For the Supraspinatus (SS) tendon, the imaging was conducted with the patient in a seated position. To ensure optimal visualization, the patient positioned the hand of the examined side with the palm resting on the ipsilateral hip. The probe was aligned transversely to the inferior aspect of the acromion, allowing both the SS tendon and biceps tendon to appear within the same image. Once the image was captured and frozen, points at 10 mm, 15 mm, and 20 mm lateral to the terminal hyperechoic margin of the biceps tendon were marked. At each marked point, the thickness of the SS tendon was measured. For the biceps tendon, the prob was positioned over the anterior aspect of the shoulder to visualize the bicipital groove and surrounding tissues. This allowed the assessment of peritendinous effusion, with particular attention to any fluid accumulation.