Can Vein Damage Cause Purple Foot After An Ankle Injury?

My90 yr old mother was stuck in the back of her left ankle with a shopping cart 3 months ago...she is still in wound care treament. Her wound if healing very slowly. She needed a pump for 2 months to draw fluids to promote healing after a deep scab was removed. I am wondering where to go from here. Whenever she puts her foot down ( even without bearing weight) her foot turns purple and feels very tight to her...worse when she bears weight on it. Could she have damaged the veins...would a vascular surgeon offer any help now?