Blood Cell Ratios as Predictors of Response to Platelet-Rich Plasma in Knee Osteoarthritis

NCT07617233 | Not Yet Recruiting

• 1 other identifier: PRP-NLR-2026
• Study Type: observational
• Target: 120
• Locations: 1 country
• Sites: 1

Brief Summary

Intra-articular platelet-rich plasma (PRP) injection is a widely used treatment for knee osteoarthritis, but patients respond to it very differently and there is currently no simple, inexpensive way to predict who will benefit. The neutrophil-to-lymphocyte ratio (NLR) and related indices derived from a routine complete blood count reflect a person's baseline inflammatory state. This prospective single-arm observational cohort study investigates whether the baseline NLR, together with the platelet-to-lymphocyte ratio (PLR), the systemic immune-inflammation index (SII), and the monocyte-to-lymphocyte ratio (MLR), predicts the clinical response to intra-articular PRP in patients with Kellgren-Lawrence grade 2 to 3 knee osteoarthritis. The investigators will enroll 120 patients aged 40 to 60 years, each of whom receives a standardized course of three leukocyte-poor PRP injections one week apart. Patients are followed for 6 months, and the primary clinical outcome is the change in the WOMAC osteoarthritis index at 6 months. Outcome assessors are blinded to patients' blood-count values. If a baseline blood ratio predicts response, it could become a low-cost tool to guide patient selection for PRP.

Conditions

Knee Osteoarthritis; Osteoarthritis

Keywords

platelet-rich plasma; PRP; knee osteoarthritis; neutrophil-to-lymphocyte ratio; NLR; systemic immune-inflammation index; biomarker; predictor; intra-articular injection; WOMAC; inflammatory index

Outcome Measures

Primary Outcomes (1)

• Change in WOMAC total score at 6 months

  Change from baseline in the total score of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at 6 months after the first injection. The primary analysis is a multivariable linear regression testing the baseline neutrophil-to-lymphocyte ratio (NLR) as the predictor of interest, adjusted for age, body mass index, Kellgren-Lawrence grade, and baseline WOMAC score.

  Baseline to 6 months

Secondary Outcomes (6)

• Treatment response at 6 months (responder versus non-responder)

  Baseline to 6 months

• Predictive value of PLR, SII, and MLR for 6-month WOMAC change

  Baseline to 6 months

• Change in WOMAC total score at 1 and 3 months

  Baseline to 1 month and to 3 months

• Change in knee pain on a Visual Analogue Scale

  Baseline to 1, 3, and 6 months

• Change in the Knee injury and Osteoarthritis Outcome Score (KOOS)

  Baseline to 6 months

Other Outcomes (1)

• Platelet-rich plasma product characterization

  At the three injection sessions (study weeks 1, 2, and 3)

Eligibility Criteria

• Age: 40 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Adult patients aged 40 to 60 years presenting to the orthopedic clinic of the University of Kyrenia, Dr. Suat Gunsel Hospital, with symptomatic primary knee osteoarthritis of Kellgren-Lawrence grade 2 or 3, who are candidates for and scheduled to receive a course of intra-articular platelet-rich plasma for the index knee.

You may qualify if:

• Age 40 to 60 years
• Symptomatic primary knee osteoarthritis, Kellgren-Lawrence grade 2 or 3 on weight-bearing radiographs
• Body mass index below 40
• Candidate for and scheduled to receive a course of intra-articular platelet-rich plasma for the index knee
• Able and willing to provide written informed consent and to attend the 6-month follow-up schedule

You may not qualify if:

• Systemic inflammatory or autoimmune disease
• Active acute infection at the time of enrollment
• Current anticoagulant or antiplatelet therapy, or current or recent chemotherapy
• Any contraindication to platelet-rich plasma per the 2025 GRIIP recommendations
• Intra-articular injection of the index knee within the previous 6 months
• Inability to comply with the planned follow-up schedule

Sponsors & Collaborators

• Utku Gürhan: lead

Study Sites (1)

University of Kyrenia, Dr. Suat Gunsel Hospital - Department of Orthopaedics and Traumatology

Kyrenia, Cyprus

Location

Related Publications (6)

• Tonutti et al. Biomed Pharmacother. 2025. doi:10.1016/j.biopha.2025.118674

  BACKGROUND

• De Luca et al. Nutrients. 2025. doi:10.3390/nu17193134

  BACKGROUND

• Lee et al. BMC Musculoskelet Disord. 2024. doi:10.1186/s12891-024-07475-1

  BACKGROUND

• Zhang et al. Front Med (Lausanne). 2026. doi:10.3389/fmed.2026.1787872

  BACKGROUND

• Louis et al. Arthroscopy. 2021. doi:10.1016/j.arthro.2021.03.074

  BACKGROUND

• GRIIP recommendations on intra-articular orthobiologics. Knee Surg Sports Traumatol Arthrosc. 2025. doi:10.1002/ksa.12682

  BACKGROUND

MeSH Terms

Conditions

Osteoarthritis, Knee; Osteoarthritis

Condition Hierarchy (Ancestors)

Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases

Study Officials

• Utku Gurhan, MD

  University of Kyrenia

  PRINCIPAL INVESTIGATOR

• Fazli Levent Umur, MD

  University of Kyrenia

  SUB INVESTIGATOR

• Enes Sari, MD

  Near East University

  SUB INVESTIGATOR

• Yakup Kahve, MD

  Ankara City Hospital Bilkent

  SUB INVESTIGATOR

Central Study Contacts

Utku Gurhan, MD

CONTACT

+90 539 112 6898; utkugrhn@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Assistant Professor of Orthopaedics and Traumatology

Study Record Dates

• First Submitted: May 20, 2026
• First Posted: June 1, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): July 1, 2027
• Study Completion (Estimated): July 1, 2027
• Last Updated: June 1, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE
• Time Frame: Beginning 6 months after manuscript publication, with no specified end date.
• Access Criteria: Reasonable request for academic research purposes; a data use agreement to be signed.

Locations

CY (1)