The Effects of Intra-articular and Peri-articular Platelet-rich Plasma (PRP) Injections ın Chronic Knee Osteoarthritis

Summary

The primary objective of this study is to evaluate and compare the effectiveness of ultrasound-guided combined intra-articular and peri-articular platelet-rich plasma (PRP) injections with intra-articular PRP injections alone in patients with chronic knee osteoarthritis (OA). The study specifically examines the effects of these treatment approaches on pain, physical function, activities of daily living, and structural parameters, including medial collateral ligament (MCL) thickness and distal femoral cartilage thickness.

Osteoarthritis is a degenerative joint disease characterized by progressive cartilage erosion, osteophyte formation, and subchondral sclerosis, leading to pain, stiffness, and functional disability. It is the most common form of arthritis and a leading cause of disability worldwide, affecting approximately 300 million individuals. Although the knee is the most frequently involved joint, OA is now recognized as a whole-joint disease, involving not only cartilage degeneration but also pathological changes in subchondral bone, synovium, and surrounding extra-articular structures.

Platelet-rich plasma is an autologous concentration of platelets suspended in a small volume of plasma and contains a variety of bioactive growth factors, such as transforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), and vascular endothelial growth factor (VEGF). These factors play a crucial role in promoting cell proliferation, angiogenesis, and tissue repair. In knee OA, PRP has been shown to reduce matrix metalloproteinase (MMP) activity, particularly MMP-13, enhance endogenous hyaluronic acid production, and support chondrogenesis. Although intra-articular PRP injections are widely accepted as a safe and effective treatment and have demonstrated superiority over placebo and hyaluronic acid in long-term follow-up studies, most existing research has focused exclusively on intra-articular applications.

Knee OA is a multifactorial condition frequently associated with extra-articular pathologies, including ligament laxity, peri-articular edema, and soft tissue inflammation. Limiting treatment to the intra-articular space alone may therefore overlook these important contributors to pain and functional impairment. Emerging evidence suggests that a combined treatment approach targeting both intra-articular and peri-articular structures may provide superior outcomes in terms of pain reduction and functional improvement.

This prospective randomized controlled trial will include 42 patients aged 40-65 years with chronic knee OA classified as Kellgren-Lawrence grade 2 or 3. Participants will be randomly assigned to one of three groups: a control group receiving conservative treatment only (exercise therapy and lifestyle modifications), a group receiving conservative treatment plus ultrasound-guided intra-articular PRP injections, and a third group receiving conservative treatment plus combined ultrasound-guided intra-articular and peri-articular PRP injections targeting the MCL and pes anserinus regions.

Clinical outcomes will be assessed using validated instruments, including the Visual Analog Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Short Form-36 (SF-36) Quality of Life Scale. In addition, ultrasonographic measurements of MCL thickness and distal femoral cartilage thickness will be performed to evaluate structural changes. By investigating the additional value of peri-articular PRP injections, this study aims to contribute to the development of more comprehensive and effective injection protocols for the management of chronic knee osteoarthritis.

Conditions

• Platelet Rich Plasma Injection
• Ultrasonography
• Gonarthrosis

Interventions

BEHAVIORAL

Conservative Therapy

Patients will receive guidance on conservative exercise therapy and lifestyle modifications. Exercise instruction forms will be provided, and patients will be shown how to perform the exercises correctly. Strengthening, stretching, and joint range of motion exercises targeting the quadriceps and hamstring muscle groups will be performed twice daily for 10 repetitions throughout the treatment period. Adherence will be monitored during follow-up visits.

PROCEDURE

Intra-Articular PRP

Patients will receive intra-articular platelet-rich plasma (PRP) injections three times at one-week intervals. Following the PRP injections, patients will receive standard post-procedure recommendations, including resting the knee joint for 1-2 days, avoiding aggressive exercise, refraining from using nonsteroidal anti-inflammatory drugs (NSAIDs), and applying warm compresses as needed.

PROCEDURE

Peri-Articular PRP

Patients will receive peri-articular platelet-rich plasma (PRP) injections three times at one-week intervals. Following the PRP injections, patients will receive standard post-procedure recommendations, including resting the knee joint for 1-2 days, avoiding aggressive exercise, refraining from using nonsteroidal anti-inflammatory drugs (NSAIDs), and applying warm compresses as needed. Peri-articular injections will be administered under ultrasound (USG) guidance to the origin and insertion sites of the medial collateral ligament (MCL), relevant joint areas, and the insertion points of the pes anserinus tendons.

Sponsors & Collaborators

• Ankara City Hospital Bilkent

  lead OTHER

Principal Investigators

• Emre ADIGÜZEL, Prof. Dr. · Ankara Bilkent City Hospital Physical Therapy and Rehabilitation Hospital

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

40 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-08-01

Primary Completion

2026-02-01

Completion

2026-04-30

Countries

• Turkey (Türkiye)

Study Locations