The clinical outcomes of intra-articular injection of human umbilical cord blood-derived mesenchymal stem cells vs. bone marrow aspirate concentrate in cartilage regeneration: a systematic review.

OBJECTIVE: This systematic review focuses on which sources of mesenchymal stem cells (MSCs) are more beneficial for cartilage repair, specifically comparing umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) and bone marrow aspirate concentrate (BMAC) in patients treated via a high tibial osteotomy (HTO) plus mesenchymal stem cells augmentation. MATERIALS AND METHODS: PubMed, Scopus, Embase, Cochrane, and Web of Science were searched for literature published in English that compared the effects of hUCB-MSC amplification and BMAC transplantation in articular cartilage lesions of the human knee with at least 1 year of follow-up after surgery. The risk of bias in the included retrospective studies was assessed via the Coleman Methodology Score. The clinical prognosis was assessed based on the total clinical score, pain, function, and degree of cartilage repair. RESULTS: The risk of bias in the included retrospective cohort studies was evaluated as fair. A formal meta-analysis of outcomes was not possible as the low evidence level and the nature of pooled retrospective studies introduced considerable heterogeneity. At an average of 1 year after surgery, two included studies reported that the ratio of normal and nearly normal cartilage repair assessed by International Cartilage Repair Society grading system (ICRS) grading in the second arthroscopy was higher in the hUCB-MSC group (Lee: 71.2% and 81.3%; Yang: 77.3%) than in the BMAC group (Lee: 45% and 40.5%; Yang: 56.8%). Ryu et al reported no significant difference between groups in the ICRS grade at 1-year post-operation (p = 0.655). Overall clinical outcome, pain and function were significantly improved at the last follow-up in both the BMAC group and the hUCB-MSC group, and there were no significant differences in these measures between groups. CONCLUSIONS: This systematic review presents evidence that compared with BMAC injection, intra-articular hUCB-MSCs can induce significantly better tissue repair at 1 year after surgery, as assessed by the ICRS grade. Although there is only short-term follow-up evidence and a lack of histochemical evidence, our systematic review supports the recommendation to use hUCB-MSCs as the source of pluripotent stem cells for treating ICRS III cartilage lesions.