Hello dear Greetings Following your symptom of ankle edema following a post knee replacement surgery with a history of bad feet bone fusion sciatica I am suggesting the following differential diagnosis Peripheral vascular disease Arthritis Myositis Tendonitis Malunion of ankle bones Cellulitis Deep venous thrombosis In view of this you will need to see an orthopaedic surgeon for further clinical assessment but before then please do the following test Doppler scan Blood culture ESR X-ray of the ankle Please take Tablet nurofen Tablet cerebrex Tablet Athrotec Continue with your physical therapy I hope this helps