This is a phase I single center open label trial study that will enroll sixteen patients requiring semi-elective below knee amputation (BKA) within a 30 day period for non-infectious complications related to critical limb ischemia (CLI). After enrollment patients will be randomized to BKA at 3,7,14, or 21 days after MSC administration. The investigational treatment uses allogeneic bone marrow derived mesenchymal stem cells at the point of care. Allogeneic MSCs will be injected in the thigh muscles and the gastrocnemius muscle of sixteen patients undergoing BKA. Through a review of treatment related adverse events over 6 months we will test the hypothesis that allogeneic MSCs do not result in significant cardiovascular, respiratory, or infectious treatment related adverse events. Through an exploratory investigation we will assess the efficacy of MSCs in promoting freedom from gangrene, conversion to AKA, and death after BKA.