Some factors that may contribute to this sensation include:
– A loose joint – if the joint is not securely attached, it will frequently move and cause discomfort. This can be caused by wear and tear, age, or a congenital abnormality.
– Tight muscles around the knee – if these muscles are tense, they can pull on the socket in a way that causes pain and instability. This is often due to longstanding lower-back pain or leg fatigue.
– Inflammation – when the knee becomes inflamed, irritated cells accumulate within its tissues. This can cause stiffness and limited range of motion.
If you are experiencing any of the above symptoms, please consult with your doctor as soon as possible. He or she may be able to recommend some conservative measures (such as resting or elevating the leg) to alleviate your pain without needing surgery.