Abstract / Summary
Background: Foot and ankle involvement is common in inflammatory rheumatic diseases.Plantar fasciitis frequently occurs in spondyloarthritis (SpA) and psoriatic arthritis (PsA), whereas tibialis posterior tendon involvement is relevant in rheumatoid arthritis (RA).Evidence for platelet-rich plasma (PRP) in autoimmune disease remains limited.Objective: This study aimed to evaluate leukocyte-poor PRP (LP-PRP) in SpA/PsA-related plantar fasciitis and RA-related PTT tendinopathy and to assess whether disease activity or structural abnormalities influenced treatment response.Materials and methods: This dual-center observational study included adults treated with ultrasoundguided LP-PRP.Outcomes included pain (Numeric Rating Scale (NRS)), power Doppler (PWD) activity, effusion, plantar fascia thickness, MRI-detected bone marrow edema (BME), and partial tendon tears.PRP was characterized according to the DEPA classification and administered without exogenous activation.Generalized Estimating Equation models were used to assess changes over time and interactions.Results: Among 101 patients (68 SpA/PsA; 33 RA), LP-PRP was associated with significant clinical and imaging improvements.In plantar fasciitis, fascia thickness decreased from 0.75 to 0.37 cm and pain from NRS 9 to 1, with resolution of PWD activity.Outcomes were similar between SpA and PsA and were not influenced by disease activity or BME.In RA, pain decreased from 8.36 to 0.48, with resolution of effusion, PWD signal, and partial tears.No disease flares occurred.Conclusions: Ultrasound-guided LP-PRP was associated with substantial clinical and imaging improvement in inflammatory rheumatic foot and ankle tendinopathies, without observed disease flares.Controlled studies using standardized PRP characterization are warranted.