A number of different types of injections have been used in an attempt to facilitate healing of chronic sporting and orthopaedic problems over the last 50 years. Cortisone injections have been used for their anti-inflammatory properties, however although steroids provide good short term relief by reducing inflammation, there appears to be limited effect on long term healing. It is also well known that repeated steroid injections can weaken connective tissue, which in rare instances has led to tendon rupture in athletes.
This knowledge has led to a change in philosophy regarding the use of injections. The aim now is to stimulate fresh tissue repair and healing through use of so called “regenerative therapies”. The simplest of these is a concentrated mixture of dextrose (a type of sugar) known as dextrose prolotherapy. More recent studies have also looked at the effects of Autologous Blood Injections (ABI) and Platelet Rich Plasma (PRP) injections for degenerative conditions.
Clinical uses for PRP injections:
- To enhance tendon and ligament repair in conditions such as tennis elbow, rotator cuff tears and jumpers knee
- To enhance bone healing in fractures
- For treatment of osteo-arthritis of the knee, hip, thumbs and other joints
When PRP injections are not appropriate:
- If there is skin infection in the local area
- If there is a local inflammatory process such as gout (generally better treated with steroid)
- If injection is required into or near a prosthetic joint (in case of a rare infection)
- If the patient is taking anticoagulation medications with reduced clotting capacity (requires caution)
Patients should ideally fast for 3-4 hours prior to having blood taken. It is OK to drink water and take usual medications. A small amount of the patient’s blood is taken from a vein at the elbow. The amount of blood taken varies according to the area treated (up to 32 ml). Platelet rich plasma (PRP) is obtained by spinning down the blood in a centrifuge for about 10 minutes. This separates the blood into a red blood cell fraction at the bottom, the buffy coat (a thin 1mm layer of white cells) and the serum (or plasma) on top. The PRP is that portion of serum just above the buffy coat layer containing a high concentration of platelet cells and growth factors. The resultant PRP may be activated by the addition of calcium chloride. As well as being rich in platelets, numerous growth factors have been identified in the PRP fraction including Fibroblast growth factor, Platelet derived angiogenesis factor, TNF-α and Connective tissue growth factor. In principle this high concentration of growth factors should lead to improved healing.
Trial of therapy
Currently most clinicians recommend a trial of 3 sessions of Platelet Rich Plasma Injections for knee osteoarthritis. The injections are usually spaced out at intervals of between 1 to 3 weeks. We recommend spacing them 3 weeks apart to give the growth factors time to work in between injections. The injections should be combined with active exercise and the results assessed at 3 months after the 3rd injection. Improvement may be seen to continue over 12 months.
The main side effect is stiffness and soreness after treatment. As no anaesthetic is used, it is more painful afterwards compared to the usual anaesthetic/steroid combination, but less painful than a whole blood injection. Typically the soreness will last for 1 to 3 days but occasionally longer. Infection is possible but much less likely than with steroid injections. Once the initial soreness settles one can expect a gradual settling of pain and improved healing over a period of 1 to 4 weeks.
There appears to be good evidence for treatment of tennis elbow; trials comparing PRP with steroid injection showed a superior outcome at 12 and 24 months. Similarly, plantar fasciitis and jumpers knee trials appear promising (Rafael Nadal had them with good results), whereas there have been mixed reports regarding Achilles tendinopathy and rotator cuff pathology. Intra-articular (within the joint itself) PRP has been trialled in osteoarthritis of the knee, with 2 small trials showing positive results. Another trial showed superiority over Hyaluronic acid (Synvisc) injections for talar dome lesions of the ankle. There have been few trials comparing PRP with Autologous whole blood (ABI). Two recent studies of tennis elbow suggested no significant differences at 6 months. No studies have compared PRP, ABI and dextrose prolotherapy.
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The above information is provided for education purposes and as general advice. The topics may or may not relate to you individually. Therefore before taking any action as a result of reading this information, speak to your health practitioner or GP for professional guidance. Please contact Brighton Spine and Sports Clinic to make an appointment with one of our specialised back care practitioners, to provide a full comprehensive assessment of your condition or for further information.