Talk to Orthopedic Surgeon on Swelling After Lumber Discectomy

My monther has undergone lumber discectomy at level L2/L3 L3/L4 on 5th December. Initially she walked with walker then she was on stick. She has recovered a lot ..now she can walk on her own without stick and her gait is penguin type . Her problem is that her both ankles and calves has swelled alot. What are the possible causes for this? She is diabetic but her sugar levels are always under control and she has no other symptoms or medical issues