Graphs comparing walking distance (A), fast-walking time (B), and mean walking speed (C) among three groups. ∗, p < .05 by Wilcoxon signed-rank test; †, p < .05 by Kruskal-Wallis test among 3 groups. Gray bars, preinjection; black bars, 4 weeks postinjection. Abbreviations: HA, hyaluronic acid; MSC, human umbilical cord blood-derived mesenchymal stem cell.