A swollen knee in a young woman needs a reason. What’s the most common cause?
Actually, I don’t know the answer to that exactly.
But when a 30-something year-old presents to her doctor with a swollen knee (knee effusion) that’s stiff and uncomfortable without a clear, recent history of trauma, it seems pretty obvious that it’s not going to be due to a torn meniscus or a torn cruciate ligament.
It’s even less likely that a referral to an orthopaedic surgeon is going to lead to any definitive diagnosis or appropriate treatment (I’m being a bit cheeky here and quite inflammatory to my orthopaedic colleagues here).
In this case, this poor lady was sent to a hospital to see a surgeon. He looked at the knee and decided it didn’t need surgery. Fortunately, the surgeon was a friend and he rang to get her reviewed by a rheumatologist asap.
Spontaneous knee effusion in a young person need to be investigated. If infection seems unlikely on the grounds of history and examination, you have to exclude an inflammatory arthritis. And most inflammatory arthritis in a female would be due to autoimmune disease.
If there aren’t any obvious clues in the rest of the history or examination, and probably even if there are, it’s usually worthwhile aspirating the joint.
You use a needle to enter the joint and you get a specimen of the excess synovial fluid. This fluid sample can be sent for analysis.
If you can actually perform the joint aspiration (and in this case, I drained 60mls), the person owning the knee will likely be quite thankful for the relief.
I also injected cortisone to help settle the joint inflammation and to prevent reaccumulation of the fluid. This is important for her comfort while I await results of investigations and attempt to work out the diagnosis, followed by a shared management plan.
What’s your experience with having a swollen knee? Was the diagnosis obvious? Did you need a joint aspiration?
