What Causes Prominent Veins In Thigh And Ankle Swelling In A Diabetic Patient?

hi, iam 42 yrs of age , female, diabetic(type II)(oct 2014 reading ,fasting is in range of 120-130and PP 230-280). I was weighing 71kgs ( before 4 months)and now I am 76kgsfor the past two months. recently have knee pain and have green veins popping out in the thigh area, swelling in the ankle..... what might be the reason?