If a component was loose in a tkr, what would it feel like?

No specific feeling: Actually, loosening components may not have any specific presentation. In many cases, it could be symptom free, and only detected on x-ray/imaging. In other cases, pain, swelling, and instability may be the presenting symptoms. Annual check-ups with your orthopedic surgeon for exam and x-rays is the best way to detect progressive component loosening.

Pain: The pain is usually worse with activity and better with rest. It usually slowly gets worse with time.