I had total knee replacement 10 weeks ago, & although I'm told my knee is doing "well", I have been almost unable to function normally since about a week after surgery due to extreme lightheadedness, fatigue & interrmittent nausea. My appetite has improved, but I've lost 13 lbs. & although I force myself to do PT, I feel like simply lying in bed. Prior to surgery I was very active, biked 15 miles & worked out at the gym several times a week. My blood work and xrays, etc., are normal, except for some hyponatremia and electrolyte abnormalities about a week after surgery which resolved. I had spinal anesthesia, (no general), & am otherwise healthy, but have never felt this ill & incapacitated. My internist has tested most everything, & cannot explain why I feel this way, & why I cannot resume my normal lifestyle. I've become very depressed & concerned. My hypertension is also poorly controlled now, & my internist has changed my medications to avoid further hyponatremia.