Swelling within an arthritic knee is common as the body produces extra fluid within the joint. The amount of fluid changes over time and can be related to activity.
Prepatellar bursitis, also known as housemaid’s knee, involves fluid accumulating in the bursa, a thin fluid filled sack area on top of the patella (knee cap), outside the knee joint.
This can be caused by trauma or overuse and results in pain and swelling on the knee cap.
If swelling continues after resting the joint or if infection is suspected, the fluid can be drained. This simple procedure can take place in outpatients. A sample of the fluid is tested for infection, which will be treated by antibiotics.
In some cases, the swelling will continue to return following draining the bursa. This may require removal of the bursa to prevent recurrence.
Gout is caused by a build-up of uric acid crystals in the joints, which leads to inflammation, swelling and pain. Pseudogout has a similar presentation, but is caused by a build up of calcium crystals.
People who suffer from gout often have acute episodes with swelling starting suddenly in one or more joint. This can be triggered by alcohol, certain foods or medicines or can have no noticeable cause.
Gout can be diagnosed by your Consultant removing a small sample of the fluid for analysis, to see if it contains crystals.
Once your Consultant has diagnosed gout or pseudogout, they can provide advice and prescriptions of anti-inflammatories and other medicines for mild attacks and provide injection therapies for moderate and severe ones.
Any trauma to the knee may result in swelling, which will come on quickly over the next 24 hours. Your swollen knee will be investigated and a sample of the fluid taken, to see if it contains blood.
The most common causes of blood in the knee are torn ligaments, most frequently the ACL or a fracture. Swelling will occur within minutes of the injury.
If there is no blood in the fluid, this can indicate a meniscal tear
or a ligament sprain. The swelling will start quickly, within hours of the injury.
Assessment of the knee following an injury is advisable to test if there is blood in the fluid and to check for damage. Surgery is not always required and your Consultant will advise you on the most suitable investigation and treatment plan for the type of injury and your activity levels.
Knee Replacement & Knee Surgery
A swollen knee following a knee replacement or major knee surgery is expected as the normal drainage of fluid in the knee is disrupted, combined with increased blood flow as the knee heals.
This swelling can last up to 6 months post surgery. If it is not associated with any other worrying symptoms like wound discharge, redness, etc. then there should be no cause for concern.
If you are concerned about the swelling in your knee post surgery, visit your GP or arrange a follow up appointment
with your Consultant so the knee can be checked for problems.
To have any type of knee swelling assessed and treated, arrange an appointment with one of our expert Consultants.