Preparation, Procedures and Evaluation of Platelet-Rich Plasma Injection in the Treatment of Knee Osteoarthritis

Knee osteoarthritis is frequently seen in the orthopedic department. We introduce in detail the entire knee osteoarthritis treatment process with platelet-rich plasma injection. Including preparation, procedures, and evaluation.

Knee osteoarthritis, KOA, is one of the most frequently seen diseases in the orthopedic department. 30 to 50%of people over the age of 65 years experience this disease, however existing non-surgical treatments have a limited effect on the repair of cartilage and on bone regeneration. Platelet-rich plasma, PRP, is an autologous bioactive substance that can repair cartilage injury and accelerate bone regeneration effectively.

And the application of PRP to bone and joint problems is being increasingly studied. The biological rational for the clinical use of PRP includes its effect on the local delivery of growth factors and modification of the inflammatory response and its positive effects on cell proliferation and differentiation. However, the reporting of PRP preparation protocols in clinical studies is highly inconsistent.

And the majority of studies do not provide sufficient information to allow the protocol to be reproduced. The manual method requires the least equipment, is convenient, is low-cost, and is simple to perform. First of all we prepare PRP by performance of manual double centrifugation.

Extract PRP layer from peripheral blood. Next use this layer to perform knee joint cavity injection. At last evaluations of the method include assessments of blood platelet concentration and clinical outcomes.

Here we describe a reproducible method of preparing PRP and treatment of KOA with PRP intra-articular injection. With evaluation of the outcome, the whole treatment procedure takes less than 30 minutes and the blood platelet concentration of PRP is proven to reach a standardized measurement. Its effectiveness is demonstrated by evaluating the outcomes during close follow-up.

Prepare the patient in a supine position in a sterile, laminar flow operating room with a comfortable room temperature and humidity. Draw point two milliliters heparin sodium. Moisten a 50 mil syringe.

Rig a tourniquet. Sterilize the elbow. Draw 30 mil peripheral blood from the elbow vein.

Perform the first centrifugation. Divide peripheral blood equally into two 50 mil sterile centrifuge tubes. Put two tubes in horizontal rotors and then in the centrifuge under aseptic conditions.

Centrifuge for six minutes with 800 G centrifugal force. Take the horizontal rotors out. Wear sterile gloves.

Then take centrifuge tubes out. Observe the stratifications to make sure the peripheral blood is stratified into two layers. Collect the supernatent liquid from one centrifuge tube into a clean centrifuge tube.

Repeat this step for another centrifuge tube. Add the supernatent layer liquid to the same centrifuge tube. Perform the second centrifugation.

Add an equivalent amount of sterile water or normal saline into another clean centrifuge tube. Put the tubes in the horizontal rotors. Mark the one with the supernatent layer liquid by adhesive plaster.

Centrifuge for five minutes at 1400 G centrifugal force. Take the horizontal rotors out. Choose the marked tube.

And by observing the stratifications, check that the liquid of the marked tube is divided into three layers. Use a 10 mil syringe to draw four mil liquid from the middle granular cell layer which is the PRP layer and part of the bottom layer of supernatent. If the middle layer quantity is sufficient, just draw four mil from that.

Put point four mil of the liquid in a sterile anticoagulation tube for evaluation, leaving 3.6 mil of liquid remaining in the syringe. Let the patient lie supine on the operating table and bend the knee to 90 degrees. Locate the puncture site at the interior margin of the patella and one centimeter from the lateral patellar ligament.

Wear sterile gloves, perform skin sterilization on the puncture site three times with anerdian three. Cover with an aseptic hole towel. Place the syringe parallel to the tibial plateau, then perform the puncture at an angle of 45 degrees.

The needle should completely insert into the skin. Inject the 3.6 mil PRP from the syringe into the knee joint cavity. Cover the puncture position with sterile gauze and fix it with adhesive plaster.

Apply pressure to the wound for 10 minutes. Observe for any severe adverse reaction for 30 minutes. The entire treatment consists of a total of three injections administered at monthly intervals.

Evaluate the concentration of blood platelets in the PRP. We use the point four mil PRP from the anticoagulation tube. Analyze the blood platelet concentration of the PRP using an automatic blood cell analyzer.

Evaluate the postoperative outcome of the PRP injection. with a consultation one day before each of the three treatments, conduct further patient followup one day after each treatment, three days after each treatment, one week after each treatment, one month after the third treatment, three months after the third treatment, and six months after the third treatment. Use a visual analog scale, The Western Ontario and McMaster Universities Osteoarthritis Index, Knee Society Score, and lysholm knee functional scale to evaluate the postoperative effect.

The platelet count of the PRP prepared in the Jove video reached a standard concentration level of 1121 times 10 to the third per microliter. We conducted the 15 followup surveys described in the protocol on a 55 year old male patient with early KAO, it was obvious that early outcome was satisfactory after the intra-articular administration of PRP. However, medium term efficacy was slightly inferior.

A markedly significant analgesic effect was observed. KSS knee score was higher than KSS function score which meant the effect of PRP on subjective symptoms was better than on objective symptoms. The lysholm knee functional scale scores indicated that our method had an evidential effect in improving cartilage injury and soft tissue injury symptoms.

Overall, the therapeutic effects of our PRP protocol were notable. It's widely believed that blood platelet concentration of PRP should reach about one million per microliter, which is three to five times normal concentrations. Therefore, a minimum requirement for this protocol is the blood platelet concentration of PRP is between these levels.

To obtain blood platelets in higher concentrations, we use double centrifugation. The collection rates of blood platelets is related to centrifugal force and time. Through the exploration of our team, we established an optimal centrifugation time for double centrifugation of six and five minutes for the first and second centrifuge.

And force is of 800 and 1400 G respectively to prepare the PRP. Finally, for the evaluation of patient outcomes, we used a number of scales. In summary, intra-articular injection of PRP is an effective treatment for knee osteoarthritis.

This study report provides the whole treatment procedure in detail, including the preparation of PRP of reliable quality, the introduction of a standard injection procedure, and a scientific and practical evaluation plan.