Plain language summary
Platelet-rich therapies for musculoskeletal soft tissue injuries
What is the medical problem?
Muscle, ligament and tendon injuries frequently occur during activities such as sports, and may be due to tissue degeneration. These injuries are more frequent in particular parts of the body, such as the tendons located in the shoulder, elbow, knee and ankle.
What treatments are available?
Several treatment options are available. These include conservative methods, such as physical therapy, and surgery, for example to repair torn tendons. Another, increasingly popular, therapy is platelet-rich therapy.
What is platelet-rich therapy?
Platelets form part of blood. They produce growth factors that assist in repair and regeneration of tissue. It is possible that if a high concentration of platelets is applied to an injury, healing may progress faster. Platelet-rich therapy involves the production of a platelet-rich (concentrated) fraction of the patient's own blood. This is then applied, such as by an injection, to the site of injury.
Does it work?
This review set out to examine the evidence to see if platelet-rich therapy (PRT) works in practice.
We searched medical databases (until March 2013) and registers of new studies (until March 2012) and found 19 studies that compared PRT with a control condition (such as no PRT). These involved a total of 1088 participants. Most participants were men, except in trials involving shoulder (rotator cuff) injuries, and elbow and Achilles tendinopathies (sometimes called tendinitis), where similar numbers of women were included.
The 19 trials covered eight types of injury, some of which were being treated surgically: rotator cuff tears (surgical repair) (six trials); shoulder impingement syndrome (surgery to release trapped tissues in the shoulder) (one trial); tennis elbow (three trials); knee ligament reconstruction using a section of tendon from the patient (four trials); the donor site of the tendon used for knee ligament reconstruction (two trials); patellar tendinopathy (jumper's knee) (one trial); Achilles tendinopathy (tendinitis) (one trial); and acute rupture of the Achilles tendon (surgical repair) (one trial).
The quality of the evidence is very low, partly because most trials used flawed methods that mean their results may not be reliable. The trials also used different ways of preparing and applying the platelet-rich plasma. We were only able to pool data for our primary outcomes (function, pain, adverse events) for a maximum of 11 studies and 45% of participants.
When we pooled the limited data that was available for all these conditions, we found very weak (very low quality) evidence for a slight benefit of PRT in pain in the short term (up to three months). However, pooled data do not show that PRT makes a difference in function in the short, medium or long term. There was weak evidence that suggested that adverse events (harms) occurred at comparable, low rates in people treated with PRT and people not treated with PRT.
In terms of individual conditions, we were able to pool results from six studies and found no differences in long-term function between those who received PRT during rotator cuff surgery and those who did not. Pooled data for short-term function from three tennis elbow studies showed a slight benefit for people receiving PRT but it is uncertain if this difference would actually be meaningful for a patient.
In conclusion, the available evidence is insufficient to to support the use of PRT for treating musculoskeletal soft tissue injuries or show whether the effects of PRT vary according to the type of injury. Any future research in this area should bear in mind the several studies currently going on and should consider the need for standardisation of the PRP preparation.