PRP vs PRP+Betamethasone vs Betamethasone Injection for Upper Trapezius Myofascial Pain

Brief Summary Myofascial pain syndrome (MPS) is a common musculoskeletal condition characterized by active trigger points (TrPs), which are hypersensitive, painful nodules within taut bands of skeletal muscle. The upper trapezius muscle is one of the most frequently affected sites. Trigger point injection (TPI) is a widely used minimally invasive treatment for patients who are refractory to conservative management. Corticosteroids provide rapid anti-inflammatory effects, whereas platelet-rich plasma (PRP) has regenerative properties through growth factors that may support tissue healing. Despite their widespread use, the optimal injectate for TPI remains unclear. Additionally, the potential benefit of combining PRP with corticosteroids has not been adequately studied in upper trapezius MPS. This study is a single-center, prospective, randomized, assessor-blinded controlled trial designed to compare the clinical effectiveness of three injection protocols: (1) PRP plus bupivacaine, (2) PRP plus betamethasone plus bupivacaine, and (3) betamethasone plus bupivacaine with saline (volume-matched control). A total of 150 patients with a single active trigger point in the upper trapezius will be included. The primary outcome is pain intensity measured by the visual analog scale (VAS) at 3 months. Secondary outcomes include pressure pain threshold (PPT), cervical range of motion (ROM), rescue analgesic use, recurrence rate, and adverse events at 1 week, 4 weeks, 3 months, and 6 months. All injections are performed by the same investigator using a palpation-guided technique, and outcome assessments are conducted by a blinded evaluator.

Inclusion Criteria: * Age between 18 and 65 years * Presentation to the Orthopedics and Traumatology outpatient clinic with neck and/or shoulder pain * Diagnosis of upper trapezius myofascial pain syndrome based on Simons and Travell criteria, including: * Presence of a taut band * Local tenderness * Referred pain pattern * Local twitch response * Presence of a single active trigger point in the upper trapezius muscle * Symptom duration ≥ 4 weeks * Pain intensity ≥ 4 on the visual analog scale (VAS) * Inadequate response to at least 4 weeks of conservative treatment (physical therapy and/or oral analgesics) * Ability to provide written informed consent Exclusion Criteria: * Presence of multiple active trigger points * Diagnosis of fibromyalgia according to ACR 2010 criteria * Cervical radiculopathy or myelopathy * Trigger point injection in the same region within the past 3 months * Coagulopathy or current anticoagulant or antiplatelet therapy * Known allergy or contraindication to corticosteroids, local anesthetics, or PRP components * Active infection (systemic or local) * Pregnancy or lactation * Thrombocytopenia (platelet count \< 100,000/µL) * Malignancy * Inability to cooperate or provide informed consent