Ultrasound-guided injections of platelet rich plasma are an increasingly popular treatment for tendon and joint pain and injury.
As a comparatively new treatment, not everyone has heard of platelet rich plasma (PRP) injections and fewer still understand how they work. Yet the science behind the treatment is relatively straightforward.
What is Platelet Rich Plasma (PRP) Injections?
PRP is extracted from the patient’s own blood by placing a sample of blood inside a centrifuge and spinning it to separate it into liquid component plasma, platelets, red blood cells and white blood cells. Once extracted, PRP contains a 94% concentration of platelets and plasma, compared to just 6% in normal blood.
The plasma contains platelets, growth factors and proteins. When injected into the site of injured or worn tendons these can help promote cellular healing and regeneration, thereby supporting the alleviation of pain.
What platelets do
Platelets play a key role in healing as they promote mitogenesis (transformation) of healing capable cells and angiogenesis (development of new blood vessels) in the tissue.
They consist of proteins known as growth factors. Among the naturally-occurring growth factors contained in PRP are platelet-derived growth factors, transforming growth factor beta, vascular endothelial growth factor and epithelial growth factor. PRP also contains adhesion molecules, such as fibrin, fibronectin and vitronectin, which promote bone formation.
The scientific evidence for PRP injections
Scientific studies have shown that PRP stimulates chondrocytes and synoviocytes which produce cartilage and also increases production of proteoglycan and leads to a greater deposition of type II collagen synthesis.
Tendons have a low metabolic rate and tend to heal slowly after injury but studies on sheep show that PRP promotes the secretion of VEGF and hepatocyte growth factor, which stimulate angiogenesis and reduce inflammatory fibrosis. In rats it was found to promote tendon-to-bone healing and remodelling.
Evidence for repair of ligament damage using PRP injections is conflicting and scientists have called for further study in this area.
What are PRP injections used for?
Platelet rich plasma injections are used to treat a range of orthopaedic conditions affecting the hip, knee, elbow, ankle and foot. The treatment takes around 45 minutes from start to finish.
What happens during treatment?
First, a sample of blood is taken from the arm of the patient. It is placed into a centrifuge machine and spun for several minutes, which separates the blood into its component parts. The platelet rich plasma is removed to be used in the injection.
Before injecting the PRP, the patient’s skin is cleaned and the area to be injected is numbed with a local anaesthetic. Ultrasound is used to guide the injection into precisely the right location to target the site of pain.
The injection site may throb for a short time after the treatment and you will need to avoid anything too strenuous for a few days but within a few weeks or months the treatment will take effect. Having physiotherapy after the injection will produce the best outcomes.
PRP injections to relieve pain and treat sports injuries – Manchester, Wigan, London
If you are experiencing tendon or joint pain, W27 offers ultrasound-guided PRP injections at a range of sites in the UK. We also provide a comprehensive range of radiology diagnostic tests and treatments delivered by leading radiologists.