Leukocyte-Poor Platelet-Rich Plasma Reduces Pain Symptoms in the Treatment of the Lateral Epicondylitis

Overview

Lateral epicondylar tendinopathy (LET), or tennis elbow, is a degenerative condition affecting the forearm's extensor tendons. It commonly leads to pain, reduced grip strength, and impaired function, particularly in individuals performing repetitive wrist and forearm movements. Standard treatments, including physiotherapy, braces, and anti-inflammatory medications, provide relief but do not always lead to full recovery. Platelet-rich plasma (PRP) has gained interest as a regenerative therapy with the potential to enhance tendon healing and improve clinical outcomes. This randomized, double-blind, placebo-controlled trial aims to evaluate PRP's effectiveness in treating LET, comparing it to leukocyte-rich PRP (L-PRP) and saline (placebo). Additionally, it assesses the composition of PRP and its role in tendon regeneration. The study will enroll 80 patients diagnosed with LET, meeting predefined clinical criteria. Participants will be randomized into three groups (PRP, L-PRP, saline) and receive two injections (day 0 and day 7). PRP will be prepared using a standardized protocol to ensure consistency. Patients will undergo clinical evaluations (VAS, Mayo Elbow Score, SECEC Elbow Score), grip strength testing, and MRI scans at baseline and 24 weeks post-treatment. The PRP composition will be analyzed in a laboratory. Follow-ups will be conducted at 12, 24, and 54 weeks to monitor pain reduction, functional improvement, and tendon healing. This study will provide critical insights into PRP's therapeutic potential, helping refine treatment approaches for LET and improve patient outcomes.

Detailed Description Study Rationale Lateral epicondylar tendinopathy (LET), commonly referred to as tennis elbow, is a chronic degenerative condition affecting the common extensor tendon (CET) at the lateral epicondyle of the humerus. It is commonly observed in individuals engaged in repetitive wrist and forearm movements, such as athletes, manual laborers, and office workers. The primary pathological mechanism involves microtears leading to pain, reduced grip strength, and impaired function. Conservative treatments, including physiotherapy, nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections, and bracing, often provide temporary symptom relief but do not facilitate tendon regeneration. Corticosteroid injections may offer short-term pain relief but have been associated with tendon degeneration and higher recurrence rates. Given the limitations of these treatments, platelet-rich plasma (PRP) has emerged as a promising biological therapy due to its high concentration of growth factors that promote tissue healing, angiogenesis, and anti-inflammatory effects. However, the optimal formulation of PRP remains controversial. Some studies suggest that leukocyte-rich PRP (L-PRP) may enhance the inflammatory response and accelerate healing, while others indicate that leukocyte-poor PRP (LP-PRP) may have superior effects by reducing excessive inflammation. The cellular composition of PRP is not standardized across clinical studies, leading to variability in treatment outcomes. This study seeks to clarify the role of PRP in LET treatment, determine whether L-PRP offers superior benefits, and evaluate its effects on pain relief, functional recovery, and tendon healing over time. Study Design and Methodology This is a randomized, double-blind, placebo-controlled clinical trial designed to evaluate the efficacy of PRP and L-PRP, saline compared to saline injections in treating LET. The study will enroll 80 symptomatic patients diagnosed with LET based on clinical criteria. Patients will be randomly assigned to one of the three treatment groups: PRP Group (n=20): Standard platelet-rich plasma injection L-PRP Group (n=20): Leukocyte-rich platelet-rich plasma injection Saline Group (Control) (n=20): Placebo (saline) injection Both PRP and L-PRP will be prepared using a standardized, non-commercial protocol to ensure consistency in cellular composition. Blinding procedures will ensure that neither the patients nor the evaluating clinicians know which treatment is administered. Patient Selection Criteria Inclusion Criteria: Age 18-65 years Diagnosed with chronic lateral epicondylitis (duration \>6 months) Positive clinical tests: pain on resisted wrist extension and decreased grip strength Written informed consent Exclusion Criteria: Previous elbow surgery or PRP treatment Corticosteroid injections within the past 3 months Systemic inflammatory or autoimmune diseases Pregnancy or breastfeeding Neurological conditions affecting upper limb function PIN syndrome Treatment Protocol Pre-Treatment Evaluation: All patients will undergo: Clinical assessment of pain and function VAS and Oxford Elbow Score questionnaires Grip strength testing using BTE MRI imaging of the affected elbow (baseline) Injection Procedure: Blood Collection: 30 ml of venous blood will be drawn from each patient Centrifugation: Blood will be centrifuged at 2054 g for 7 minutes to separate PRP fractions PRP/L-PRP Preparation: The appropriate PRP fraction will be extracted (with or without leukocytes) Injection: 2 ml of PRP or L-PRP will be injected into the CET, with 1 ml retained for laboratory analysis Control Group: Patients will receive an equivalent saline injection following the same procedure Post-Treatment Rehabilitation: Guided physiotherapy program focusing on eccentric strengthening Use of elbow braces during daily activities Activity modification guidelines Outcome Measures and Follow-Up Primary Outcome: Pain reduction measured by VAS score Secondary Outcomes: Functional improvement assessed using Oxford Elbow Score Grip strength recovery using a digital dynamometer BTE Structural tendon healing assessed via MRI at baseline and 24 weeks post-treatment Follow-Up Schedule: Week 0: Baseline assessments and first injection Week 1: Second injection Week 12: First follow-up visit (VAS, Oxford Elbow Score, grip strength) Week 24: Second follow-up visit (MRI assessment, VAS, Oxford Elbow Score, grip strength) Week 54: Final follow-up visit (long-term clinical evaluation, VAS, Oxford Elbow Score, grip strength) Laboratory Analysis PRP samples will be analyzed for platelet concentration, leukocyte content, and growth factor levels Comparative analysis between PRP and L-PRP to correlate biological composition with clinical outcomes Expected Impact and Clinical Relevance This study aims to establish a standardized PRP protocol for LET treatment and determine whether PRP offers superior benefits compared to conventional approaches. The results will provide: High-quality evidence for clinicians regarding PRP effectiveness Guidance on PRP formulation (leukocyte-rich vs. leukocyte-poor) Objective MRI data to track structural healing of the common extensor tendon Improved treatment strategies to enhance patient recovery and reduce recurrence rates By correlating PRP composition with clinical and imaging outcomes, this trial will help refine biologic treatment strategies for chronic tendinopathies, ultimately improving evidence-based management of LET.