In simple terms, the patient’s own blood is drawn from a vein into a test tube and placed into a centrifuge. Centrifugation causes the heaviest blood components (red and white blood cells) to collect at the bottom of the tube. The layer of plasma above this contains a high concentration of platelets which are then activated to release growth factors with healing properties.
Most of the evidence for the use of PRP in OA comes from knee studies. These studies suggest that about 80% of patients with knee OA who undergo a course of PRP injections experience decreased pain and stiffness and improved knee function for 6-12 months.
The magnitude and duration of the effect is generally related to the severity of OA (ie. those with milder OA are more likely to benefit and have longer-lasting pain relief). Though its use in other joints is still being studied, PRP can be used for OA in any joint to try to relieve arthritic pain when other treatment options have not been successful. The protocol for PRP injection used by Dr. Lewis is two injections spaced 4 weeks apart.
The full benefits can take up to a month to appear and to achieve best results it is recommended to have concurrent physiotherapy treatment to help strengthen the joint. As the effect of PRP starts to wear off, “top-up” injections can be done at 6, 12 and 24 months.
Injuries to tendons can occur both acutely and from overuse. Whilst tendons will initially attempt a healing response after an injury, if this process repeatedly fails, eventually the tendon may cease all attempts at healing. The result is a tendon that is unable to adapt to attempts at rehabilitation.
The goal of PRP injected into a degenerative tendon is to initiate a healing response. However PRP is not a miracle cure on its own and it is best administered in conjunction with an appropriate tendon rehabilitation program for best results.
As PRP comes from the patient’s own blood, side effects are generally restricted to those related to the injection process itself, rather than the product that is injected. Fainting and dizziness or bruising at the injection site are the most common problems encountered.
Most people will experienced increased discomfort for a few days post injection and it is recommended to avoid strenuous exertion until pain returns to pre-injection levels. Infection is a rare complication (approximately 1 in 10,000).