Hi Barbara - I had an MRI on my knee a couple of years ago. The main difference between this and the x-ray is that it shows more of the soft tissue. The x-ray will show what bone damage there is, but only the MRI will show the cartilage. Your knee is a very complex joint and there is cartilage on the end of each bone that provides a cushion when they rub together. There are also bits of cartilage on both sides of the joint. Any of this cartilage can get worn down by normal wear and tear (osteo-arthritis) or through injuries (like playing football or skiing). The joint is encased in stuff called the synovial capsule which holds the synovial fluid (like the oil in your car engine). When your knee is swollen and painful it might be because there is excess fluid or it might be because the synovial capsule is inflamed and "puffy". A simple x-ray can't see what is swollen or if the cartilage is damaged, but an MRI can show this detail.
As I understand it, RA causes inflammation of the synovium, and that's what causes the pain (and eventually leads to bone damage). Steroid jabs are very effective at controlling this inflammation and therefore reducing the swelling and pain, but obviously the consultant will need to understand what's happening inside your knee before deciding where to put the injection. There might be other complications but again the MRI gives an very clear picture.
In my case, the MRI showed that I had a torn cartilage due to an old skiing injury, so my left knee has always been weaker than my right knee, and that's where the RA attacked the worst - RA always seems to go for your weakest points!!! Anyway, I had a simple operation to trim the torn cartilage, and then later on I had a steroid jab in the knee, and that's pretty much fixed the problem. I still have to be careful as the knee is not as perfect as it once was and I've got a bit of osteo-arthritis too (well I'm 54!!), so for example I avoid kneeling down, and I don't run, and I use hiking poles for any long-distance walking, and I exercise to keep my leg muscles strong - but it doesn't have to rule my life. I keep aware of how stiff the joint is, and when the RA flares a bit, I just rest more and do my limbering-up exercises (tai-chi) to keep the joints moving and so far so good.
Hopefully in your case it's good news that they need an MRI as that suggests they are just looking for soft tissue damage and that can be controlled by anti-inflammatories, steroids and your dmards. If the inflammation can be controlled then that will delay any damage to the actual bones themselves.
Good luck with the MRI - remember to lie nice and still and relax - it doesn't hurt and they even play soothing music because it does take half an hour or so to complete the scan. (I fell asleep and woke with a start and they had to take it again because I made it blurred - whoops!!!)
Best wishes - Sylvia xx
Be kinder than is necessary because everyone you meet is fighting some kind of battle
