Background
To treat lateral compartment osteoarthritis caused by a valgus deformity, partial or total knee joint arthroplasty is recommended. However, for young patients, joint preservation surgery such as distal femoral osteotomy (DFO) can be an alternative treatment option. Combined cartilage defects of lateral compartment osteoarthritis can be restored by human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs). This case report presents the results of DFO and hUCB-MSC implantation for treating two patients with valgus deformity who had lateral compartment osteoarthritis.