I have had surgery to repair a menial meniscus tear. The Baker's cyst I have behind my right knee was present before the surgery. It has hardened a great deal and is about the size of a golf ball. I have had it drained and rec'd a cortisone shot to no avail. It is even affecting my back now since I can't stand up straight because of the right knee cyst. Should I have it surgically removed and what are the possible negative side effects of this?