Hi welcome to HCm I have gone thru your query regarding severe upper abdominal pain after total knee replacement surgery . It is a matter of great concern . Dear , I am sure , your pain has no connection with your knee surgery . Upper left abdominal pain is most often due to a condition afflicting one or more organs or structure in the LUQ (left upper quadrant) of the abdomen. It may also be due to conditions in the thoracic cavity or lower left abdominal area that either refers or radiates to the LUQ. Constipation , Pancreatitis , enlarged SPLEEN , stone in kidney or ureter , conditions that may cause left side abdominal pain . Any of the above conditions may be cause of your present agony The severe pain Ultimately a diagnosis by a medical professional is necessary so that the appropriate treatment can be commenced as soon as possible. Your doctor may suggest abdominal ultrasound, x-ray, CT scan or MRI are often necessary for a definitive diagnosis . Meanwhile , Rest until you are feeling better. Drink plenty of fluids to prevent dehydration. You may find that taking small, frequent sips of a beverage is easier on your stomach than trying to drink a whole glass at once. Drink lemon juice in a glass of water with a pinch of salt and black pepper , thrice a day , is very energetic , good appitiser and alley pain very fast . Try eating several small meals instead of 2 or 3 large ones. Eat mild foods, such as rice - moong dal khichi , oats , porriage , crushed an inch of ginger with salt and black pepper . Do not use aspirin or medicines, may irritate your stomach and increase your pain. `avoidingAvoid fried fast foods too much of sugar, tea, coffee ,alcohol , smoking ,stress ,constipation . Pranayam - deep breathing , Vajjarasan , mandookasan , Bhujjangasan , lying on right side can help . If problem persists or worson ,rush to your ASAP . Hope this helps solves your query .Take care , All the best . Don t hesitate to get back if have any further query