Comparison of the short-term efficacy of intra-articular platelet-rich plasma injection alone versus intra-articular platelet-rich plasma injection combined with high-power laser therapy on pain and physical function in patients with grade 1-3 knee osteoarthritis

Comparison of short-term efficacy of intra-articular PRP alone vs PRP combined with HILT in knee OA (grades 1-3).

Randomized controlled trial, parallel group, single-blind (patient-blinded), 48 patients (24 per group), block randomization (4 blocks of 12) using random number software, allocation concealment with sequentially numbered sealed opaque envelopes.

Patients at Imam Khomeini Hospital’s physical medicine clinic (Tehran) were split into two groups of 24. Group 1 received one PRP injection; Group 2 received the injection plus high-intensity laser. Assessments (VAS and Persian WOMAC) were done before, 1 month, and 3 months post-injection. The laser operator was unblinded (single-blind).

Inclusion criteria: 30-70y; knee OA grade 1-3 (ACR criteria); pain≥6 months; VAS≥3; failed conservative Tx; washout≥2 weeks for NSAIDs/cortisone; no injection in last 3 months. Exclusion criteria: pregnancy; inflammatory arthritis; severe heart disease; skin infection; immunosuppressants/anticoagulants; bleeding disorders; active radicular low back pain; knee surgery in last 3 months; active infection/malignancy in last 6 months; substance abuse; intra-articular corticosteroid (3 months) or hyaluronic acid (6 months). Controlled diabetes allowed.

Group 1 (PRP alone): Single intra-articular PRP injection (4 mL, platelet concentration 5-6 times baseline, prepared by double centrifugation of 20 mL whole blood with anticoagulant). Group 2 (PRP+HILT): Single PRP injection (same protocol) followed by one session of HILT (pulsed mode, max power 12W, average 7W, dose 50 J/cm² per 64 cm², frequency 10 Hz, duration 6 minutes).

Pain severity (Visual Analogue Scale - VAS); Pain subscale of WOMAC; Stiffness subscale of WOMAC; Physical function subscale of WOMAC.

Method: Block randomization (restricted randomization) with fixed block size of 12. Four blocks will be used, each containing 6 allocations to PRP alone group and 6 allocations to PRP+HILT group. Unit of randomization: Individual patient. Tools: Random number generation using R software to randomly select 4 numbers from 1 to 4 for block order. Allocation concealment using sequentially numbered, sealed, opaque envelopes. Each random sequence is recorded on a card placed inside an envelope. Envelopes are numbered externally in sequence and opened in order of participant enrollment.

This is a single-blind (patient-blinded) study. The blinding is achieved as follows: Participants (patients): Blinded. For patients in the PRP-only group (Group 1), a sham laser procedure is performed with the same device, same duration (6 minutes), same positioning and sound effects, but with zero watt power output. Patients in the PRP+HILT group (Group 2) receive real laser therapy. All patients are unaware of their group allocation. Principal investigator: Not blinded. The investigator knows which patient receives which intervention. Healthcare providers (interventionists/laser operator): Not blinded. The laser operator must know the actual power settings to deliver real or sham laser accordingly. Data collectors: Not applicable separately, as outcome assessors are described below. Outcome assessors: Blinded. The physician or trained personnel who administer the VAS and WOMAC questionnaires at baseline, 1 month and 3 months follow-up are unaware of the patients' group allocation. Assessments are performed before laser session (for Group 2) and at the same time points for both groups. Data Safety and Monitoring Board (DSMB): Not applicable (no DSMB for this trial). Manuscript writers: Not blinded during analysis; however, group allocation will be coded (e.g., Group A and Group B) until final analysis is completed.

After deidentifying people, all the data obtained from the research, including the demographic information of the samples, clinical information and the results of the intervention can be shared.

It is possible to access the results after nine to twelve months from the publication of the results.

Researchers in academic centers and scientific research centers.

In order to data comparison in similar studies, the researchers of academic centers and scientific research centers have the possibility to receive data and re-analyze it if they comply with the principles of ethics in research.

Dr Alireza naeiji with below email address: alirezanaeiji3@gmail.com and phone number:+989116899200

Researchers should send a written request to receive data to the relevant email address.A week after receiving an email , it will take action.