The Mechanism of Action of Unite Biomatrix in Venous Leg Ulcers

Inclusion Criteria: * venous ulcer confirmed w/ duplex ultrasound * ulcer greater than 6 months duration * post-debridement, the ulcer size must be \>5cm2 * at least 18 years old * ABI is between 0.7 to 1.2 and/or one of the following: * TcPO2 \> 30mmHg at the ankle * Doppler waveform consistent with adequate flow in the foot (biphasic or triphasic) * able and willing to provide a voluntary written informed consent * three or fewer ulcers separated by \>3.0 cm distance * able and willing to attend scheduled follow-up visits and study related exams Exclusion Criteria: * greater than 20% reduction in wound size during the first 2 weeks of observation with the investigator * ulcer with exposed bone or tendon * clinical infection at the studied ulcer site including cellulitis and osteomyelitis * ulcer of a non-venous insufficiency etiology * phlebitis or deep leg vein thrombosis in past 30 days * arterial bypass in previous 30 days * severe anemia (Hgb\<8) * serum albumin \<3.0 * uncompensated congestive heart failure * renal failure with Creatinine \>2.5mg/dl * rheumatoid arthritis (and other collagen vascular disease), vasculitis, sickle cell disease, HIV * severe liver disease as defined by treating physician * uncontrolled diabetes mellitus determined by treating physician * malignancy at or near the ulcer site * any condition judged by the PI that would cause the study to be detrimental to the patient * known allergy to equine derived tissue * received another investigational device or drug within 30 days of Day 0 * radiation therapy at the wound site * chemotherapy or immunosuppressive therapy within 30 days of enrollment * received another allograft, autograft, xenograft within 30 days of the study * pregnant or nursing women