Efficacy of Platelet-Rich Plasma Combined With Hyaluronic Acid in Knee Osteoarthritis

Effect of Adding Platelet-Rich Plasma to Hyaluronic Acid on Outcomes of Injection Therapy for Knee Osteoarthritis: A Prospective, Randomized Comparative Study

This prospective, randomized, open-label, single-centre post-market clinical follow-up (PMCF) study evaluates the clinical performance and safety of a single intra-articular injection of hyaluronic acid (HA) combined with autologous platelet-rich plasma (PRP) compared with a single intra-articular injection of HA alone in adults with symptomatic knee osteoarthritis (Kellgren-Lawrence grade II or III).

Knee osteoarthritis is a chronic degenerative joint disease associated with pain, functional limitations, and reduced quality of life. Hyaluronic acid is widely used as viscosupplementation therapy, while platelet-rich plasma provides autologous growth factors that may contribute to the modulation of inflammatory processes and tissue healing. The combination of HA and PRP may provide complementary effects and may offer additional clinical benefit compared with HA alone.

A total of 50 participants will be randomized in a 1:1 ratio to receive either a single intra-articular injection of 3.8 mL HA combined with 1 mL autologous PRP or a single intra-articular injection of 4.8 mL HA. Participants will be followed for 18 months.

The primary endpoint is the between-group difference in the change in knee pain, measured using the Numeric Rating Scale (NRS), from baseline to Month 6. Secondary outcomes include changes in pain intensity, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Knee Injury and Osteoarthritis Outcome Score (KOOS), quality-of-life measures, and safety assessments throughout the follow-up period.

Both medical devices are CE-marked and are used for their intended purpose. The study is conducted as a PMCF investigation in accordance with Regulation (EU) 2017/745 (MDR).

Inclusion Criteria:

• Knee osteoarthritis meeting American College of Rheumatology (ACR) criteria
• Kellgren-Lawrence radiographic grade II or III
• Pain intensity in the study knee NRS >= 4 and in the contralateral knee NRS <= 2
• Written informed consent

Exclusion Criteria:

• BMI >= 40 kg/m2
• Surgery of the same or contralateral knee within the previous year
• Intra-articular corticosteroid injection into the study joint within 3 months, or hyaluronic acid, platelet-rich plasma or other intra-articular injection therapy within 6 months before enrolment
• Systemic corticosteroid use within 2 weeks
• Systemic inflammatory or autoimmune disease with joint involvement (rheumatoid arthritis, spondyloarthropathy, systemic lupus erythematosus, etc.)
• Oral corticosteroid treatment
• Deep vein thrombosis
• Pregnancy or breastfeeding