knee surgery

I had surgery 12-18-08 on my knee area. I had fallen and had a muscl. tear and a cyst. I had been getting ster. injections, and cart. injections since the previous May when I fell, trying to avoid surgery.  Surgery with scope (3 holes) when great and I felt very optomistic. But in late Jan. My knee area swell 3-times the size and I could not bend it or get around that good. I was taking pen. for a tooth infection, and it seemed to get better and the swelling went down about half by the time I could see the Doc. He drew off 5 tubes of fluid and told me it was worst than he thought when he operated, and said my knee cart. was 70% gone, even though my mri didn't suggest this. He cleaned it out, fixed the tear and got rid of the cyst.  what causes fluid like that? It does feel better, but he wants me off of it longer. I love my Doc. and I was told it would be awful getting the fluid off the knee, but he never hurt me !  If the fluid is caused by infection, should I be on medicine, or should the fluid be checked that he got out of my knee? Should I question this and is this normal?  Thank-you Rurh Ireland

[Michael L Gross, MD]

I am assuming that you mean you had a meniscus tear, not a muscle tear.  It also sounds like you had somewhat more arthritic changes in your knee than your surgeon expected.  The cyst is probably a Baker's cyst, a popliteal cyst, and is usually caused by the collection of fluid in your knee. It will continue to recur until the fluid is completly gone. Treatment for the cyst is treatment for whatever is going on in your knee; when that is resolved, the fluid collection ceases and the cyst goes away.  As far as the fluid itself, if there are no other signs of infection, then the index of suspicion for infection is low.  However, if fluid is aspirated again, it can be sent to the lab for culture and gram staining, as well as other tests.  In the mean time, cortisone injections, oral NSAID's, ice and physical therapy are in order.