Platelet-rich plasmas (PRP) in tendon and joint pathologies of the upper limb

Posted by prpmed on March 23rd, 2021

What is PRP Platelet Rich Plasma?

The plasma is a serum including clotting factors and proteins.

The platelets are cells coreless with mitochondria, microtubules and alpha granules .

There are between 50 and 80 alpha granules per strip. These alpha granules synthesize, store and release around thirty bioactive proteins, which are growth factors whose function is hemostasis (blood coagulation) and tissue healing .

How do growth factors work?

Following tissue damage , the repair process takes place in 3 phases .

First, tissue inflammation is initiated by the platelets . During this phase, platelets release a large amount of growth factors.

In the second phase, these growth factors activate cell and matrix (tissue around cells) proliferation. The architecture of the scarred tissue is done in an anarchic way.

Finally, this cascade of growth factors leads to tissue remodeling , that is to say a reorganization of scar tissue.

How do you prepare and use PRPs?

The preparation of PRP requires a blood sample with PRP-Set, which is centrifuged with PRP-centrifuge to separate the Platelet Poor Plasma (PPP representing 5% of the blood) on the surface, the Platelet and Fibrinogen Rich Plasma (PRP representing 40% of the blood) in the middle, granulocytes and leukocytes at the bottom of the PRP tubes (accounting for 55% of the blood).

The PRP is performed for each patient from their personal blood sample.

Cellular centrifugation increases the concentration of platelets and growth factors , by removing alpha granules from platelets, making them active. The proportion of alpha granules in the serum thus increases from 200 to 600%, depending on the centrifugation process employed.

To be fully effective, 2 to 3 injections 4 to 6 weeks apart are necessary.
The injection can be painful because the use of local anesthetic is impossible, the pH of the anesthetic product disturbing the activation of the platelet granules.

What are the different types of PRP?

Depending on the material used and the single or double centrifugation, the composition of PRP, used in osteo-ligamentous pathologies, can be variable in terms of the concentration of platelets and growth factors. In addition, it must not contain granulocytes or leukocytes and must not be coagulated , otherwise the healing cascade is disturbed.

What precautions should be taken when injecting PRP?

Nonsteroidal anti-inflammatory drugs (NSAIDs) should not be used the days before and two weeks after the injection of PRP, as they may inhibit the action of prostaglandins and thus the stimulatory effects of PRP. Local anti-inflammatory treatments , including the application of a cold pack, should also be avoided . In case of pain, paracetamol will be used.

What are PRPs used for?

It is known that in vitro PRPs have a favorable action on bone, cartilage and tendon cells.
But in vivo the process is poorly understood, because there are major interactions between growth factors, but also opposing actions between some of them. These mechanisms differ according to the tissues and according to the healing phase, making the extrapolation of in vitro studies to medical practice uncertain. This is why randomized clinical studies have been carried out to scientifically prove the action of PRPs.

The use of PRP in osteoarthritis

For now, there is no study on osteoarthritis of the shoulder or elbow, but many studies have been done for the knee and seem extrapolable.

A meta-analysis of the use of PRP in the pathologies of osteoarthritis was carried out on a series of 20 in vivo and in vitro studies of level 1 (best level). This study shows that the following effects of PRP on osteoarthritis:

• anabolic stimulation (repair) of cartilage
• decreased catabolism (destruction) of cartilage
• beneficial effect on joint homeostasis (ability to maintain balance)
• decreased inflammation and synovial hyperplasia (development of the membrane around the joint).

PRP are therefore effective in the early stages of osteoarthritis . In the more advanced stages of osteoarthritis, PRPs are not very effective because the cartilage is too worn out to be able to regenerate.

PRP versus hyaluronic acid in osteoarthritis of the shoulder

Hyaluronic acid has been used in the treatment of early stage osteoarthritis for many years. It is now put in competition with the PRPs.

The use of PRP seems possible in osteoarthritis (osteoarthritis of the shoulder). In fact, a study of 10 patients suffering from osteoarthritis of the knee , showed that PRP have greater efficacy and more stable effects over time than hyaluronic acid. To date, there is no specific study for osteoarthritis of the shoulder, but these results are probably extrapolable.

PRP and torn cuff tendons

Some surgeons use PRP to speed up tendon healing after cuff repair.

A meta-analysis of 70 studies was performed (3); only 5 studies were retained as being significant. The findings indicate that at present there is no clinical improvement in recovery after use of PRP. On the other hand, it would seem that we find fewer re-ruptures after MRI control in the groups using PRP for lesions of small or intermediate size.

PRP and tendonitis of the cuff

So far, few studies have been carried out on cuff tendinopathies, but if we correlate with the many studies done for epicondylitis, PRP should be effective in calcifying and non-calcifying tendinopathies.

However, a study carried out on 20 patients does not seem to show clinical improvement.

PRP and tendinopathy of the elbow (epicondylitis)

A meta-analysis of 9 randomized level 1 studies (best level) shows clinical improvement with the use of PRP in elbow tendinopathies

Conclusion

• Effects of PRP proven in numerous studies on several pathologies: little developed osteoarthritis, unbroken tendonitis.
• No indication in tendon ruptures
• No indication in advanced osteoarthritis
• Therapeutic place in third line, after standard medical treatments (non-invasive): physiotherapist, infiltrations, shock waves ...
• Need 2 to 3 injections in the same way as hyaluronic acid
• Easy method of administration, but injection may be painful
• Problem of the cost: for the moment this is a gesture outside the social security nomenclature, which is therefore not or little reimbursed.