Outcomes of High Tibial Osteotomy With Versus Without Mesenchymal Stem Cell Augmentation: A Systematic Review and Meta-analysis

BACKGROUND: The outcomes after high tibial osteotomy (HTO) with augmentation of intra-articular mesenchymal stem cell (MSCs) for medial tibiofemoral osteoarthritis remain controversial. PURPOSE: To pool existing studies to compare the outcomes of HTO with versus without intra-articular MSC augmentation when performed for medial tibiofemoral osteoarthritis. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: The systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were clinical studies that compared the outcomes of HTO with intra-articular MSC augmentation (MSC group) versus without (control group). Pre- and postoperative outcomes were compared between groups from measures including the Lysholm score, International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score, Hospital for Special Surgery Knee Rating Scale, Tegner score, visual analog scale for pain, arthroscopic and histological grading scales, femorotibial angle, weightbearing line, and posterior tibial slope. RESULTS: We reviewed 4 studies with a total of 224 patients. The MSC group demonstrated significantly greater improvement versus controls in the pooled Lysholm score (weighted mean difference [WMD], 6.64; 95% CI, 0.90 to 12.39) and pooled IKDC score (WMD, 9.21; 95% CI, 4.06 to 14.36), which were within or close to the minimal clinically important difference. Radiological outcomes were similar in both groups, including the femorotibial angle (WMD, –0.01; 95% CI, –1.10 to 1.09), weightbearing line, and posterior tibial slope. The studies were homogeneous, and no publication bias was noted. CONCLUSION: Intra-articular MSC augmentation for HTO may modestly improve functional outcomes as compared with HTO alone. However, adequate data are lacking to make definitive conclusions regarding the effect of MSC augmentation on pain or arthroscopic and histologic grading.