Clinical outcomes of human umbilical cord blood derived mesenchymal stem cells application in knee osteoarthritis patients

Abstract

Purpose: There are many animal studies on the articular cartilage regeneration using stem cells, but studies on stem cell treatment on human are rare. For patients with knee osteoarthritis with full thickness cartilage defect (> 2.0 cm2), we have been using human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) to regenerate articular cartilage since 2012. The purpose of this study is to analyze the effect of hUCB-MSCs based cartilage regeneration surgery on the preoperative and postoperative changes of symptoms, function and arthroscopic findings. Methods: After standard arthroscopic examination, the cartilage defect site was exposed through small arthrotomy or arthroscopy. Then, multiple drill holes (2-5mm in diameter and 5mm depth) were made approximately 2-3 mm apart at the cartilage defect site, and hUCB-MSCs mixture was implanted in the drill holes of the lesion. Patients with varus or valgus deformity greater than 5 degrees were treated simultaneously with osteotomy. Among 253 patients (276 knees) who underwent hUCB-MSCs surgery from February 2012 to October 2017, we reviewed 64 patients (76 knees) who underwent second-look arthroscopy after postoperatively 1 year. Cartilage regeneration was graded according to Oswestry Arthroscopy Score (OAS). Functional outcomes using subjective International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and visual analog scale (VAS) were evaluated at preoperative and postoperative 1 year. Results: Totally 76 knees (64 patients; mean age, 59.8 ± 8.7 years; age range, 31 to 79 years) underwent second-look arthroscopic surgery at postoperative 1 year. The average preoperative cartilage defect is 4.4 ± 1.1 cm2 (range, 2.0 to 5.9 cm2). IKDC score improved from 22.9 points preoperatively to 69.3 points at postoperative 1 year. WOMAC score (mean 52.3 points preoperatively to 13.4 points at postoperative 1 year) and VAS score (mean 7.7 points preoperatively to 1.9 points at postoperative 1 year) all significantly improved at postoperative 1 year. The mean OAS were significantly improved from 5.6 ± 1.8 preoperatively to 2.1 ± 2.4 at postoperative 1 year. There was no complication due to hUCB-MSCs application itself, but in 2 kness, there was poor cartilage regeneration, pain persisted, so converted to TKA. Conclusions: Although there is no histological study and lifespan of the regenerated cartilage, the cartilage regeneration using hUCB-MSCs showed significant pain and function improvement, and excellent arthroscopic findings of cartilage regeneration. These results suggest that hUCB-MSCs application surgery is good treatment option for patients with severe knee osteoarthritis of relatively younger age to perform TKA surgery.