Hip and knee surgery

PRP (Platelet Rich Plasma)


Platelet Rich Plasma (PRP), first described in 1998, is a biological product derived from the centrifugation of blood in a tube containing an anticoagulant. It is a liquid product defined as a platelet suspension in plasma characterized by a higher platelet concentration than the whole blood of the patient. The PRP is intended for autologous use (for each patient himself). A multitude of different PRP exist according to the preparation protocol, more or less rich in leucocytes, more or less pure, more or less concentrated.

Platelets contain a natural reservoir of growth factors in their alpha granules, which are the active substance in PRP. These growth factors are TGFβ (transforming growth factor beta), PDGF (platelet-derived growth factor), IGF1 (insulin-like growth factor), FGF1 (fibroblast growth factor), EGF (epidermal growth factor) and VEGF ( vascular endothelial growth factor).

They are involved in the proliferation and cell differentiation of keratinocytes, fibroblasts, endothelial cells, chondrocytes, smooth muscle cells and myoblasts, and are involved in the healing of cartilage tissue. Platelet alpha granules also contain bioactive molecules such as serotonin, histamine, dopamine, adenosines, calcium, catecholamines, which play a fundamental biological role in the three phases of cartilage repair (inflammation, proliferation, remodeling).Platelet concentrates would also have bacteriostatic properties, demonstrated on Staphylococcus epidermidis and Staphylococcus aureus, thus reducing the risk of microbial contamination of the treated area.

The treatment of traumatic and degenerative pathologies of the osteoarticular apparatus has aroused a great interest on the part of surgeons in recent years. In osteoarthritis, the majority of clinical trials and case series concern the treatment of osteoarthritis of the knee, the results of which are promising. In 2017, Laver showed a significant good results with PRP compared to hyaluronic acid (read the summary of this study here). In 2013 Patel showed a significant improvement in knee pain and function at six months with PRP compared to placebo (read the summary of this study here).

The preparation of PRP requires a blood sample, which is centrifuged to separate platelet poor plasma (PPP, 5%) at the surface, platelet-rich fibrinogen plasma (PRP, 40%) in the middle, granulocytes and leukocytes at the bottom of the tube (55%). The cell separator makes it possible to increase the concentration of platelets and growth factors contained in their alpha-granules by 200 to 600%. Depending on the material used and the single or double centrifugation, the composition of the PRP may be variable in terms of platelet concentration and growth factors; it must not contain granulocytes or leucocytes and must not be coagulated.

The use of a local anesthetic before the injection of PRP is not recommended by the majority of authors, it would change the local pH, but the quality of the PRP is very pH-dependent. The platelet-concentrated plasma is then reinjected into the pathological zone. These platelets release growth factors in large numbers, allowing scarring of injured tissue by stimulating local stem cells, and reducing inflammation and hemorrhage.

NSAIDs should not be used on the previous days and two weeks after PRP injection, they may inhibit the action of prostaglandins and thus the stimulatory effects of PRP. Local anti-inflammatory care should also be avoided. In case of pain, use paracetamol.


Before the session, it is important to report any fever, any infection, any skin lesion (wound in particular), any drug intake especially aspirin, anticoagulant, platelet antiaggregant, allergy to iodine. It is important to report a blood disorder, frequent or prolonged bleeding, pregnancy. One to three injections are needed, one week apart.

On arrival, a blood sample will be taken in a vein, under strict aseptic conditions, with a single-use material. The use of a double syringe allows closed circuit blood handling (a small syringe in a large syringe). A few ml of blood placed in a centrifuge and then carefully handled under the enclosure of a sterile hood, usually used for the manipulation of anticancer drugs (hence the reason for your presence in the chemotherapy unit of Clairval). Platelet-rich supernatant plasma will be injected into your knee. After the injection, a dry dressing is put in place and will be maintained for 24 hours. It takes about 30 minutes for all the procedure.

After the session, rest is essential, the effectiveness of the treatment depends in part, for 48 hours, during which you apply ice regularly (20 to 30 minutes 4 times a day, using a hermetic pouch) and if necessary use paracetamol. Physical activity will be gentle between each session. The effect will not manifest until after a few weeks. The re-education and the resumption of the sports activity will be progressive. Depending on your professional activity, infiltration may require a temporary stop of your work.

The only complication although very rare, even if all the precautions are taken, is the infection. According to recent studies, under the conditions of realization in office, their incidence is of the order of 1 infection for 70,000 infiltrations. They occur within 48 to 72 hours. In case of fever or significant pain in the days following the infiltration (possible signs of infection), it is important to contact me immediately, either at my office ( or or at clinic standard (0826.666.966).

You will be reviewed in consultation with a 3-month control imaging to evaluate the effectiveness of the treatment.


The French CPAM does not reimburse this treatment. A preliminary estimate will be given to you. If the PRP injections concerned an injury that has been the subject of a declaration of accident to an insurance (leisure activity, sports license), you can claim from this insurance the possible reimbursement of expenses.


The stem cell combined to the PRP injections seems to be very interesting : this is a real innovation.
But, today, these PRP can’t be legally combined with the use of stem cells. The French FDA doesn’t have enough in-the field data to assess the efficiency of this blended mix and didn’t give this authorization yet.

Our colleagues from Montreal have some experience about stem cell injections : you can get a glimpse of here.