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

ConditionsKnee Osteoarthritis Osteoarthritis

Trial statusNot yet recruiting

Trial phaseNot listed

Trial typeObservational

Biological sexAll

Age40-60

SponsorUtku Gürhan

About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

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

Disqualifiers

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

Trial 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.

Trial design

Design model

Cohort

Time perspective

Prospective

Treatments tested in this trial

Not listed

Trial groups

No trial groups listed

Trial outcomes

Primary outcomes

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.

Time frame

Baseline to 6 months

Secondary outcomes

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

Treatment response is defined a priori as at least 30 percent improvement in WOMAC total score together with fulfilment of the OMERACT-OARSI responder criteria. The discriminative performance of the baseline NLR for responder status is assessed by receiver operating characteristic analysis with the optimal threshold identified by the Youden index.

Time frame

Baseline to 6 months

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

Association of the baseline platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and monocyte-to-lymphocyte ratio (MLR) with the change in WOMAC total score at 6 months, evaluated by multivariable regression.

Time frame

Baseline to 6 months

Change in WOMAC total score at 1 and 3 months

Change from baseline in WOMAC total score at the 1-month and 3-month assessments, describing the trajectory of clinical response.

Time frame

Baseline to 1 month and to 3 months

Change in knee pain on a Visual Analogue Scale

Change from baseline in knee pain on a Visual Analogue Scale at the 1-month, 3-month, and 6-month assessments.

Time frame

Baseline to 1, 3, and 6 months

Other outcomes

Platelet-rich plasma product characterization

Two-tier quality control of the PRP product. Tier 1 (all 120 patients, all 360 batches): final platelet concentration, total leukocyte count, and final volume. Tier 2 (a pre-specified validation subset of approximately 40 patients, approximately 120 batches): leukocyte differential and erythrocyte contamination.

Time frame

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

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Utku Gürhan

Lead sponsor

University of Kyrenia

Sponsor institution

Source ClinicalTrials.gov

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