Lateral epicondylitis (LE), also known as tennis elbow, has an estimated prevalence in the general population of 1% to 3%, peaking at age 45 years to 54 years and affect both men and women equally. A randomised controlled trial published in The Lancet showed that 83% of the patients suffering from LE of more than 6 weeks duration on wait-and-see policy recovered only after 1 year without any therapeutic interventions. The costs associated with LE is substantial as patients not only incur hefty healthcare costs but also lose their productivity owing to their long recovery period.

Currently, there is a paucity of evidence worldwide for the efficacy of PRP injections compared to control in LE. This randomised controlled trial aims to compare the efficacy of PRP versus placebo (saline) injections in adults with LE.

The pathogenesis of LE was initially believed to be a generalised inflammatory process. However, in 1979, the pathology was better understood as invading immature fibroblasts disorganizing the normal collagen architecture of the elbow, associated with immature vascular responses to cellular repair. There is a variety of treatment modalities available for LE, varying from watchful waiting without any therapeutic interventions, pharmaceutical methods such as prescribing non-steroidal anti-inflammatory drugs, physiotherapy such as encouraging bracing and exercise, injections, and surgical modalities once non-surgical options fail.

For many years, injection with glucocorticoids has remained the mainstay of treatment. However, several studies have proven that the effects of corticosteroid injections do not seem to last in the long-term, amongst which a trial published in The Lancet showed that long-term differences at 52 weeks between injections and physiotherapy was significantly in favour of physiotherapy. Recently, many studies worldwide have demonstrated that platelet-rich-plasma (PRP) stimulates cartilage repair by actively secreting growth factors which activate cell proliferation and differentiation thereby promoting tissue regeneration. It has been postulated that PRP stimulates repair mechanisms within tendons and hence promote tendon healing.

However, there is a paucity of evidence worldwide for the efficacy of PRP injections compared to control in LE. Currently, PRP treatment is not formally recognized as a treatment modality for LE in Singapore, with the accepted indications for PRP treatment being limited to non-surgical treatment of acute muscle and ligamentous injuries, and the biological augmentation of acute Achilles tendon repairs.

This randomised controlled trial aims to compare the efficacy of PRP versus placebo (saline) injections in adults with LE.

Inclusion Criteria:

• Patients of age >21 years old
• History of chronic pain on the lateral side of the elbow and pain on lateral epicondyle on direct palpation and resisted dorsiflexion of the wrist for more than 3 months
• Ability of patients to provide informed consent

Exclusion Criteria:

• Previous tennis elbow surgery to affected elbow
• Previous corticosteroid injections to affected elbow
• Concurrent complementary and alternative medicine (CAM) treatments e.g. acupuncture
• Inflammatory diseases / infection / fracture / trauma
• Neck pain on ipsilateral side
• Chronic pain syndromes
• Malignancies
• Pregnant or lactating females
• Consistent use of NSAIDs within 48 hours of procedure
• Systemic use of corticosteroids within 2 weeks
• History of anemia, any blood disorders, hypothyroidism

Both the patients and the outcome assessor will be blinded in this trial.