Knee swelling can result from fluid within the knee or can be due to swelling around the joint. Common causes of swelling within the knee are injury - for example anterior cruciate ligament injury where there is bleeding into the joint which occurs rapidly after the injury. If you have developed sudden swelling in the knee following a twisting injury then it is important that your knee is assessed to identify the cause of this sudden swelling. Other causes of swelling within the joint include knee arthritis where the lining of the joint is inflamed and this causes more fluid to be produced than is absorbed. This situation can also occur after surgery and sometimes occurs spontaneously. If the knee is extremely swollen it is possible in some cases to relieve pressure by removing the excess fluid and at the same time inject the knee with local anaesthetic and steroid. It is however important to identify the cause of swelling within the joint.
In order to assist making a diagnosis you may require x-rays of your knee and an MRI scan. Sometimes taking fluid from the joint can also assist in making a diagnosis. If your knee swells up dramatically associated with severe pain and great difficulty moving the joint, this could signify an infection within the knee. Rarely this occurs out of the blue and requires urgent investigation - particularly if you feel unwell and shivery. Sometimes this can occur following surgery and again this requires urgent investigation.
When you see Simon to discuss management of knee swelling, he will take a careful history and examine your knee. He will talk about the necessary investigations and after discussion with you decide on a plan of management. Sometimes knee swelling will settle but sometimes this requires physiotherapy or a surgical procedure.