Summary

This study demonstrates the clinical and radiological outcome of intra-articular leukocyte-poor PRP injections for the Japanese patients with osteoarthritis of the knee at a mean follow-up of three years.

Abstract

Introduction

We have previously confirmed the safety and feasibility of intra-articular platelet-rich plasma (PRP) injections for the Japanese patients with osteoarthritis (OA) of the knee.

Purpose

The purpose of this study was to investigate the clinical and radiological results of the patients with a mean follow-up of three-years.

Methods

This was a retrospective study of 10 knees in 10 patients treated between March 2014 and June 2015. The population was composed of 10 females, with a mean age of 60.6 years (51-70). Knee OA was graded according to the Kellgren-Lawrence (KL) radiographic classification as grade 1 in 4 patients, grade 2 in 4, and grade 3 in 2. PRP was prepared using single centrifuge technique (2100 rpm, 8 minutes, PRGF-Endoret, BTI Biotechnology Institute) classified leukocyte-poor (LP)-PRP. Treatment protocol was a total of three intra-articular injections with 6.0 mL volume at weekly intervals. Patients were evaluated at baseline and final follow-up using Japanese Orthopedics Association (JOA) score which represent standard tools for assessing knee function in Japan and KL grade. Further, presence/absence of additional treatment at a final follow-up were also investigated.

Results

At a mean follow-up of three-years, 9 knees in 9 patients with a mean age of 64.3 years were reviewed (follow-up rate was 90%). One patient, KL grade 3 with varus deformity and ACL mucoid degeneration was converted total knee arthroplasty at 7 months after PRP injections. In the remaining 8 patients, JOA score was improved from 75 points (p) to 83.8 p (sub-categorical score was as follows; gait 23.1 to 26.9 p, stairs 12.5 to 17.5 p, ROM 30 to 30 p, swelling 9.4 to 10 p). KL grade was maintained in 6 patients (75%) and progressed in 2 patients from grade 1 to 2 and grade 2 to 3. Presence of additional treatment at final follow-up was in 2 patients (25%) with lateral wedge insole or hyaluronic acid injection.

Discussion

The most important finding of this study is that knee functional score, especially gait and up-down stairs ability were improved in six of 8 patients (75%) without additional treatment at a final follow-up. The result suggests that LP-PRP gives efficacious and safe outcomes in the majority cases at a mean follow-up of three-years. A limitation of this study is small number of subjects. To verify the true efficacy double-blind RCT is currently in progress.