The purpose of this study is to compare the effectiveness of V.A.C.® Therapy to moist wound therapy of diabetic foot ulcers. The primary objective is to determine the effect of V.A.C.® Therapy on the incidence of complete wound closure. Secondary objectives include: evaluating the acceleration of ulcer closure or facilitation of surgical closure, reduction of ulcer surface area over time, reduction in complications, the quality of life and the average total cost of care.