Efficacy of Intra-articular Platelet-Rich Fibrin Injection for Periarthritis of the Shoulder: A Pilot Study

Background Periarthritis of the shoulder (adhesive capsulitis) is a common and disabling condition characterized by pain and progressive restriction of shoulder motion. Conventional treatment modalities often provide inconsistent long-term outcomes. Platelet-rich fibrin (PRF) is an autologous biological product with regenerative and anti-inflammatory properties, though evidence for its intra-articular use in periarthritis remains limited. Objective To evaluate the clinical outcomes and safety of a single intra-articular injectable PRF (i-PRF) injection in patients with periarthritis of the shoulder. Methods This prospective single-arm interventional pilot study included 30 patients with periarthritis of the shoulder of less than six months' duration. All patients received a landmark-guided intra-articular i-PRF injection (approximately 3-4 mL) prepared using low-speed centrifugation (700 RPM, 60g at radius 110 mm, 3 minutes). Outcomes were assessed using the visual analog scale (VAS), Shoulder Pain and Disability Index (SPADI), and shortened Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) at baseline, immediate post-procedure, and at 2, 4, 8, and 12 weeks. Statistical analysis was performed using repeated measures analysis of variance (ANOVA). Results All patients completed the 12-week follow-up. Mean VAS scores improved significantly from 7.8 ± 1.2 at baseline to 1.5 ± 0.7 at 12 weeks (81% improvement, Cohen's d = 6.45, P < 0.001). SPADI scores improved from 68.5 ± 10.2 to 22.5 ± 6.3 (67% improvement, Cohen's d = 5.42), and QuickDASH scores from 65.3 ± 11.5 to 21.8 ± 7.1 (67% improvement, Cohen's d = 4.71) (P < 0.001 for both). Active range of motion improved significantly: forward flexion by 78.3°, abduction by 75.7°, and external rotation by 32.5° (all P < 0.001). Progressive improvement was observed at all follow-up intervals. No serious adverse events were reported. Conclusions Intra-articular PRF injection was associated with significant and sustained improvement in pain and functional outcomes in periarthritis of the shoulder, with an excellent safety profile. These preliminary findings support further randomized controlled studies to establish definitive efficacy.