My job as an Orthopaedic surgeon is challenging, fun and interesting. I often get to play detective as I search for clues and evidence as to why my patients are having certain symptoms, pain, and dysfunction. I can usually make a diagnosis based on a physical examination, talking to the patient in detail about their symptoms and asking lots of specific questions. However, when I need to know what is really going on biologically or chemically in the synovial fluid inside of a joint, that’s when I whip out my trusty needle and syringe and draw out a sample for testing.
We all know how popular it is when I say “Hey, I’m gonna’ stick this big needle into your knee (hip, shoulder, elbow, etc.) joint and pull out some fluid!” You may groan under your breath, “Yeah, it won’t hurt you at all” as you steel yourself for the needle. Believe me, I get it. But there is an entire microbiome living inside that fluid that can give me incredible information about the health of your joint AND your entire body for that matter. That’s why it is so important.
At OSC, we will do everything possible to make the needle aspiration as comfortable as possible. If you get woozy, we are happy to have you lie down while we perform the procedure. We use ultrasound so that our providers can precisely know where the needle is in the joint for perfect placement. We also use a numbing cold spray right before the injection, which helps to give your mind something else to think about. Have you ever noticed how I usually will ask you a question about your kids or vacation right when giving you an injection? That’s another trick to get you to focus on something else besides the injection! Sneaky, I know. Usually, by the time you start to feel any real discomfort, the aspiration is over, and the injection of the medication begins. Typically, you only feel pressure, but that too is over quickly. We put a big, impressive band-aid on the injection site and let you check-out as soon as you are ready to go.
You may or may not know this, but when we withdraw fluid from a joint, we replace it with something or it will fill back up on its own, often with too much fluid. Orthopaedists prefer to replace it with medication that will help with the pain and inflammation. At OSC, we use a combination of Depo-medrol® (a corticosteroid) and Marcaine® (a numbing agent) when we do an aspiration of synovial fluid from a joint.
So, for what diagnoses do I order needle aspiration of the joint? That’s a great question! I can order testing of the synovial fluid to see if my patient may have rheumatoid arthritis or other inflammatory markers that signal autoimmune diseases that produce symptoms in the joints. I can also see if the patient has a crystalline disorder, such as gout.
If a patient comes in for a consult with a painful, red and swollen joint, with a fever, I often ask whether or not infection could be to blame. There are certain risk factors for a joint infection that I will also look for: a history of diabetes, previous injury near the joint, recent surgery, past joint replacement, STDs, etc. Viruses, bacteria, and fungi may all cause infection in the lining of the joint. I can look at the color, amount, and viscosity of the synovial fluid for clues as well. Does it have blood in it that may signal a fracture or injury? While I can guess, a lab will be able to tell me, with certainty, everything I want to know, so I can best know how to treat the patient.
Treatment may require antibiotics for a bacterial infection, a fungicide for a fungal infection, a referral to a rheumatologist if rheumatoid arthritis is detected or may indicate any number of other treatment options, including surgery. If the joint isn’t infected, sometimes the bursa sacs near the joints can be. We may draw fluid from those to see if the patient has infectious bursitis and we will treat that with antibiotics. As I said in the beginning of this article, I must be a bloodhound sometimes, but eventually, with the help of my patient and a good lab, we’ll get to the bottom of even the trickiest hidden diagnosis.
Make an appointment with Dr. Carlson or another OSC provider by clicking the “Request Appointment” button below or by calling (757) 596-1900.