Does the Radius Contain Bone Marrow Mesenchymal Stem Cells?-A Comparison between Cells of the Iliac Crest and Radius in Kienbock's Disease

Background: Numerous studies have indicated the presence of mesenchymal stem cells (MSCs) in the bone marrow aspirated from the vertebral body, distal femur, proximal tibia, humeral head, sternum, and iliac crest. However, their presence has not been reported in the radius thus far. In this study, we aimed to compare the number of MSCs in bone marrow aspirated from radius and iliac crest in patients with Kienbock's disease. Furthermore, we examined the association between the number of MSCs in the bone marrow and patient age. Methods: A total of 17 patients were recruited. Owing to difficulties in obtaining samples for 5 cases, only 12 cases were included. Hematological analyses and fibroblastic colony-forming unit (CFU-F) assay were performed using bone marrow samples aspirated from the radius (group R), the first sample aspirated from the iliac crest (group I-1), and the second sample aspirated from the iliac crest (group I-2). The CFU-F numbers among the three groups were compared using Mann-Whitney U-test. Pearson's correlation coefficient was calculated to evaluate the association between the CFU-F numbers and patient age. Results: The average numbers of CFU-Fs/ml in the bone marrow samples from the R, I-1, and I-2 groups were 3.4, 57.3, and 13.7, respectively. The CFU-F number in Group I-1 was significantly higher than that in the other two groups; the CFU-F number was lower in group R than in group I-2. The correlation coefficients were -0.168, 0.166, and 0.036 for samples from groups R, I-1, and I-2, respectively. No significant association between the CFU-F numbers and patient age was observed. Conclusions: The presence of MSCs in the radius was indicated by CFU-Fs in patients with Kienbock's disease. The number of CFU-Fs was lower in the radius than in the iliac crest; the CFU-F number was not associated with patient age.