Although blood mainly consists of a liquid called plasma, it also contains a number of other components including red cells, white cells, and platelets. Platelets circulate in the blood and play a crucial role in blood clotting. They also contain proteins called growth factors, which are needed to stimulate the healing of injuries.
Platelet-rich plasma (PRP) is plasma produced from a person’s blood that has a much higher platelet concentration than usual. The platelet concentration and therefore growth factor concentration in PRP can be three to five times greater than would usually be present in the blood.
Injection of this PRP, enriched with platelets and growth factors, is becoming a popular option for boosting the body’s natural healing process in cases of injury to the tendons, ligaments, joints, cartilage, bone, and muscles. In some cases, PRP therapy can reduce the need for medication or surgical approaches to musculoskeletal problems. Although researchers are not sure exactly how PRP injection therapy works, studies have shown that the enriched concentration of growth factors in PRP has the potential to increase the speed at which healing occurs.
Preparation and Injection of PRP
To prepare PRP, a patient’s blood sample is spun in a centrifuge to separate the platelets from other blood components and produce platelet-rich plasma that can be collected and treated. The PRP preparation is applied to the injury site via an injection, which may be administered under the guidance of ultrasound or X-ray, to ensure PRP placement is precise. A single injection or a series of injections may be recommended, depending on the injury being treated and how the patient responds to initial therapy.
Once the injection has been given, the patient must avoid exercise or weight-bearing activity for 3 to 7 days, before gradually returning to their usual physical activities. For the period immediately following injection, a doctor may recommend the use of a cast, boot, or brace.
Since PRP is produced using a patient’s own blood, there is very little chance of a reaction occurring. However, as with any injection, there is a minimal risk of infection and injury to nerves and tissues in the area.
Researchers are currently carrying out studies to assess the effectiveness of PRP, which can vary depending on the injury site being treated, as well as the patient’s overall health and whether the injury is acute or chronic. The areas where PRP is currently being studied as a therapy are discussed below.
Chronic Tendon Injuries
According to the research currently reported, PRP is an effective treatment for chronic tendon injuries, particularly the common injury “tennis elbow.” PRP has also showed promise as a treatment for other chronic tendon injuries including Achilles tendonitis and jumper’s knee (inflammation or injury of the patellar in the knee). However, whether PRP is more effective than conventional treatments is yet to be established.
Acute Injury to Ligaments and Muscles
PRP has received a lot of publicity for its potential in treating acute sports injuries. It has been used to treat common injuries among athletes such as pulled hamstring muscles and knee sprains, although no conclusive evidence is currently published that proves PRP enhances healing in these injuries.
PRP has also been used during some kinds of surgery, to aid tissue healing. It was initially thought to be of benefit in surgery that corrects tears in rotator cuff tendons and knee ligaments. However, to date, studies have been unable to show any significant benefit of applying PRP in these types of procedures.
Some preliminary studies have looked at the effectiveness of PRP in treating the arthritic knee, but it is still too soon to know whether PRP will be any more beneficial than current therapies.
So far, no studies have shown PRP to be of any significant benefit in accelerating the healing of fractures.
In conclusion, although PRP does seem to be a beneficial treatment for patients with chronic tendon injuries, further research is needed before the effectiveness of PRP in other conditions can be determined.
Reviewed by Susha Cheriyedath, MSc Further Reading