Clinical efficacy of electroacupuncture at different frequencies for acute-stage periarthritis of the shoulder (Hand-Shaoyang meridian type)

INTERVENTION: Low Frequency Group (2 Hz):Electroacupuncture (continuous wave, 2 Hz), intensity adjusted to participant tolerance, 30 min per session, with concurrent TDP heat irradiation to the shoulder. Acupoints: LI15, SJ14, LI14, ST38 (connected to EA), plus SJ11 and SJ5 (not connected). Once daily; 5 consecutive days per course, 2‐day interval between courses; 2 courses in total.;High‐frequency group (100 Hz):Electroacupuncture (continuous wave, 100 Hz), intensity adjusted to participant tolerance, 30 min per session, with concurrent TDP heat irradiation. All acupoints, needling procedures, and treatment schedule are identical to the 2 Hz group; only the EA frequency differs. Once daily; 5 days per course with a 2‐day interval; 2 courses total.; CONDITION: Acute‐stage periarthritis of the shoulder (Hand‐Shaoyang meridian type) M75.0 PRIMARY OUTCOME: Visual Analogue Scale (VAS); SECONDARY OUTCOME: Constant‐Murley Score Shoulder Assessment (CMS);Activities of Daily Living (ADL) scale;Range of Motion (ROM); INCLUSION CRITERIA: (1) Meets the diagnostic criteria for periarthritis of the shoulder (Frozen shoulder), including the classic Codman five signs/diagnostic points, and conforms to the TCM syndrome differentiation criteria for this study (Hand Shaoyang Meridian type/Leoshanfeng‐related classification, as per the protocol/guidelines). (2) 40 = age = 80 years old, gender, unilateral onset, duration of illness <36 weeks; (3) No specific treatment for periarthritis of the shoulder has been received within 2 weeks of this onset (including but not limited to intra‐articular injection therapy, nerve block therapy, surgical therapy, etc.); (4) Voluntarily signs the Informed Consent Form, agrees to participate in this study, and has no major health conditions (including but not limited to infections, coagulation disorders, heart disease, tumors, etc.); (5) Good compliance, able to adhere to the treatment.