MRI-Confirmed Resolution of Persistent Radiocarpal Synovitis and Ulnar Styloid Bone Marrow Oedema Following Single High-Concentration PlateletRich Plasma Injection: A Case Report

Persistent monoarticular radiocarpal synovitis with associated ulnar styloid bone marrow oedema (BMO) presents a significant diagnostic and therapeutic challenge, particularly when systemic inflammatory disease cannot be definitively established. Differentiating early inflammatory arthritis from localized osteochondral pathology is essential to prevent unnecessary long-term immunomodulatory therapy and to ensure appropriate targeted management. Magnetic resonance imaging (MRI) is central to evaluation. Bone marrow oedema is increasingly recognized as an active subchondral pathological entity characterized by trabecular microinjury, increased vascularity, inflammatory cell infiltration, and altered bone remodelling rather than simple fluid accumulation. The concurrent presence of synovitis and BMO reflects biological interaction within the osteochondral unit, potentially perpetuating pain, inflammatory signalling, and structural dysfunction at the radiocarpal joint. We report the case of a 40-year-old female with a two-year history of persistent radiocarpal synovitis and progressive ulnar styloid BMO. Hydroxychloroquine was initiated following a single positive antinuclear antibody titre (1:320); however, repeat autoimmune serology was negative, inflammatory markers remained normal, and established classification criteria for systemic lupus erythematosus were not fulfilled. Symptoms persisted despite multiple corticosteroid injections. After discontinuation of systemic therapy, a single ultrasound-guided injection of high-concentration, leukocyte-poor platelet-rich plasma (PRP) was administered. was administered targeting the radiocarpal joint and ulnar styloid region. Four-month follow-up MRI demonstrated complete resolution of radiocarpal synovitis and ulnar styloid BMO, with interval healing of the previously torn triangular fibrocartilage complex (TFCC). This case underscores the importance of diagnostic precision in isolated wrist synovitis and suggests that localized biologic modulation of the synovium– subchondral bone interface may represent a promising therapeutic strategy. Prospective controlled studies are warranted to confirm reproducibility and further elucidate the underlying biological mechanisms.