Corticosteroid vs Platelet-Rich Plasma Intra-articular Injections in the Treatment of Knee Osteoarthritis.

This study will explore the effectiveness of intra-articular knee injections in patients with osteoarthritis by comparing Corticosteroid (triamcinolone) vs Platelet Rich Plasma (PRP).

This study is a randomized controlled trial with a sample size of one hundred and sixty patients (160). Patients would be recruited via new referrals and follow-up appointments in the Orthopaedic clinic at the UHWI (University Hospital of the West Indies) with knee osteoarthritis.

The recruitment period will run from July 31, 2023 to January 31, 2024 and a subsequent year of follow-up for each patient.

Selected patients will be informed of the study and given informed consent to fill out once they meet the inclusion criteria. Information will be stored on a password-encrypted external storage device that can only be accessed by the investigator or supervisor. Data will be analyzed using Statistical Package for the Social Sciences (SPSS).

The study will be conducted according to the good clinical practice guidelines of the World Medical Association (WMA) declaration of Helsinki which addresses research on human subjects and will conform to local laws and ethical requirements of the Ministry of Health.

The study will provide information on the effectiveness of two non-operative management of osteoarthritis of the knee; in the form of Platelet-rich plasma and corticosteroid injection. Results from the study can be used as a reference point for future treatment in patients with knee osteoarthritis.

Hypothesis:

PRP is superior to corticosteroid intra-articular injection over one year for knee pain and functional outcome in patients with osteoarthritis of the knee

Design This study is a randomized controlled double-blinded trial. Patients with knee osteoarthritis would be recruited via new referrals and follow-up appointments in the Orthopaedic clinic at the UHWI (University Hospital of the West Indies).

The intervention will be done in the minor operating room at no additional cost to the patient. All the equipment needed will be provided via funding.

• Using the WOMAC scores and visual analogue scale, pain and functional outcomes before and after the procedures will be studied to assess if PRP injection is superior to steroid injection.
• Selected patients will be informed of the study and given an informed consent to fill out once they meet inclusion criteria. Persons consenting will be Orthopaedic residents knowledgeable of the study but will not be a part of the care.
• One person who is not a part of analyzing the data will be in charge of assigning the unique identifying number to each tested knee prior to the start of the study.
• WOMAC questionnaire will be administered at the outpatient clinic visits prior to injection, at two weeks, three months, six months, and a year post-injection.
• Information will be stored on a password-encrypted external storage device that can only be accessed by the investigator or supervisor. Data will be analyzed using Statistical Package for the Social Sciences (SPSS)

Research-related justification for sample size:

The sample size was calculated to be one hundred and sixty patients (160). Calculations for the sample size were done using the formula to calculate the sample size for a two-sample test of means; independent samples T-test. Where:

The type I error rate (5%) The type II error rate (20%)

= The effect size (set at 0.5 for a medium effect size).

Yields a sample size of 64 participants for each group. It is recommended to account for a loss to follow-up of at least 20%, bringing the sample size required for each group to 80, for a total sample size of 160.

Additionally, when considering sample size estimates a larger sample size is always considered better. To estimate a linear regression model to control for other factors such as age and sex, Green (1991) recommends that the sample size should be at least 50 +8*(number of predictors). When seeking to test individual predictors, Green's rule of thumb for a medium effect size is that the sample size be at least 104 + predictors.

Using the estimate of 160, the study should be adequately powered for analysis testing the hypothesis of WOMAC pain scores being different in the group receiving PRP injections compared to the group receiving corticosteroid injection, while controlling for 2 - 3 other characteristics.

Patients will be randomized with the help of an online randomization tool (National Cancer Institute Clinical Trial randomization tool) being placed in one of two arms, corticosteroid vs PRP injection.

Patients will be recruited by the investigator and recruited for the study over 6 months with a further follow-up of up to one year post-injection. The persons assessing the patients at each visit plus the physiotherapist will not be aware of the intervention given.

Patients will be given a single injection of either PRP or corticosteroids (triamcinolone).

All injections will be given by persons post part 1 in the Doctorate of Medicine Orthopaedic program or higher except for the investigators. All patients will have 30 ml of blood taken in an area separate from the location of the centrifuge machine to prepare the PRP.

Patients and administrators will be blinded to the injection by wrapping each syringe before injection. All patients will be injected 20 minutes after the blood has been drawn. The tubes will be sorted by an individual who will know about the desired randomization. Patients will be blinded to the injection as the syringe will be wrapped to hide its content, this will also blind the person administering the injection; who is separate from the person preparing.

The steroid injections are commercially packaged as 40mg/ml. 80 mg of triamcinolone will be used for patients receiving steroids. Preparation of the PRP will be done by the PRP method.

PRP method:

1. Obtain 30mls Whole Blood by venepuncture in acid citrate dextrose (ACD) tubes
2. Do not chill the blood at any time before or during platelet separation.
3. Centrifuge the blood using a 'soft' spin.
4. Transfer the supernatant plasma containing platelets into another sterile tube (without anticoagulant).
5. Centrifuge tube at a higher speed (a hard spin ) to obtain a platelet concentrate.
6. The lower 1/3rd is PRP and upper 2/3rd is platelet- poor plasma (PPP). At the bottom of the tube, platelet pellets are formed.
7. Remove PPP and suspend the platelet pellets in a minimum quantity of plasma (2-4 mL) by gently shaking the tube.

The procedure will be done in the minor operating theatre. Patients will be adequately cleaned with betadine or hibitane in alcohol before venepuncture. Blood will then be brought to a separate sterile room for preparation. Injections will be given under aseptic conditions. The area will be cleaned thoroughly with Povidone-Iodine or Hibitane in 70% Alcohol, depending on the allergy profiles of the patients. With the knee flexed to ninety degrees injection will be given with a 22 gauge needle through the lateral parapatellar space. Dressings will then be applied and patients will be observed for five minutes after the injections, post-procedural analgesics will be given for two days.

Patients will be assessed before injection, at 2 weeks, 3 months, 6 months, and a year post-injection using the WOMAC (Western Ontario and McMaster Osteoarthritis index) and Visual Analogue Score (VAS), by a trained physician who will be blinded to the interventions. There will also be a standardized rehab program for osteoarthritis of the knee developed by the physiotherapy department. This program will be administered for a duration of 6 months to all patients by volunteer registered Physiotherapists in the department.

The proposed start time of the study is July 2023 with the recruitment of patients over 6 months, followed by a one-year follow-up for each patient.