Before I forget, I want to let you know that I created a special work sheet to go along with this podcast. If you fill it out, I promise it will help you to ask your doctor important questions and think about whether or not an MRI is going to get you back to running faster. Go to DocOnTheRun.com, go to the Show Notes page for Episode #68 and download the “MRI Questions to Ask Your Doctor.” It’s free.
Yesterday Kelly sent in a great question.
“I recently had some pain during the last 2 weeks of my marathon training. I begrudgingly took some time off to recover and unfortunately had to skip my marathon due to the pain. After 3 weeks and still having some pain I went to an orthopedic doctor and got an x-ray. The x-ray showed a stress fracture, but the doctor said the fracture appeared to be healing already. The doctor suggested I get an MRI. Knowing that MRIs are not cheap and me being on a budget, is it essential I go get the MRI or can I let my body heal and return to running once the pain has gone away? I’ve continued to keep my fitness levels up through biking and swimming and am hoping to be able to compete in an upcoming marathon in early December. It will be my first marathon and I am trying to qualify for Boston. Thank you so much for all your help. Your podcasts are amazing and I have learned so much from you. Thanks again! Kelly”
First of all, Kelly, thanks for sending in your question! I am sorry to hear about your stress fracture, but I am glad to hear you are already starting to heal!
Now for the most part, I stay out of my wife’s health unless she specifically asks me for help. I do not offer unsolicited advice. But one night we were out to dinner and she told me how it was getting was and not better.
I said, “I know this isn’t any of my business, but you need an MRI because I think you have a stress fracture in your femur.” Based on her story, her symptoms, her failure to respond to the treatments she was receiving I was 100% certain she had a stress fracture.
She got an MRI. And guess what. The MRI showed a stress fracture. It sucks to always be right about these things, but at least she wasn’t wasting any more time with soft tissue work when she actually had a bone problem.
The first thing you have to understand about an MRI is that it doesn’t actually provide a 100% clear picture. And although a complete discussion about MRIs is beyond the scope of this episode I do think it’s worth giving a basic description of how an MRI actually works. An MRI, in the simplest sense, provides imaging of tissues using a big
powerful very expensive magnet and a computer.
The images that result from an MRI look very accurate. But they are not hundred percent accurate. Basically an MRI creates the image based on the differences in water content or fat content of the tissues. It’s all about different ratios of water versus oil.
For example, inside the bones you have bone marrow. Bone marrow is mostly fat. That is basically a solid form of oil. So if you have a set of images on your MRI called the T-2 images the bones look black. The bones are very dark because they are mostly filled with fat and there is very little water in them. On the same images the veins and arteries will all look bright white. That of course is because the veins and arteries are filled with blood which is mostly water. They’re complete opposites. So in those images on an MRI anything containing oil or fat looks dark and anything containing water looks bright white.
So a normal bone looks dark black. But when you get a stress fracture your body responds with inflammation. Inflammatory fluid, like blood and most other fluids in your body are mostly made up of water. So if you have an inflammatory response within a bone, because you have a stress fracture, then you end up with inflammatory fluid, or water inside the bone, which show was up as a bright white signal on the image.
When you see your radiology report the radiologist will usually mention this bright white area as a “signal change” or “increased signal intensity.” But when you look at the image you just see that the bone the irritated bone looks bright white.
The stress fractures always become very irritated. There’s lots of inflammation within the bone. This is very easy to see you on an MRI.
So if you are not certain whether or not you actually have a stress fracture, or you have some other injury that seems to be behaving like a stress fracture, you can get an MRI and an MRI will definitively rule out a stress fracture. Because if you don’t have a stress fracture the bone will looked just as dark as all the other bones.
A stress fracture is actually a whole range of trouble. I live in California and we often talk about earthquakes. And earthquakes provided good analogy for stress fractures. If somebody said, “hey did you feel that earthquake today?” That could mean lots of different things. It could mean that you actually felt a tiny vibration while you were sitting on the couch. It could mean you actually saw a pendant lamp swing very slightly for a second or two. It could mean that you actually felt the ground move so much you almost fell down. And in the worst possible scenarios buildings can fall down and people can be killed. But all of those different stages of moving and shaking, but are still called earthquakes.
Here’s a really good way to think about stress fractures. Take a coat hanger, hold it in your hands. Start bending it back and forth several times. After you bend it just a couple of times if you feel the part of the coat hanger you’ve been bending it will actually feel warm or even hot. If you keep bending it and then you look at it you’ll actually see some opacity or change in the surface of the metal suggesting that it’s becoming damaged. If
you keep bending back-and-forth you’ll eventually start to see cracks in the surface of the metal. If you bend it a few more times it’ll break into two pieces.
So the beginning phase of a stress fracture is really more analogous to when you just bent a coat hanger a couple of times. It’s warm. It’s hot. It’s inflamed. That’s part of the reason nothing shows up on most x-rays when people think they have a stress fracture. But all of that stress and heat will show up on MRI. The only problem is that the MRI doesn’t really show you how far along that continuum you are unless there’s a big crack
in the bone. And again, even when there’s a crack sometimes MRI will miss it.
So it is true that in the same way and MRI can rule out a stress fracture it can also tell you that your foot is completely calmed down, If you’re willing to wait many months after the stress fracture heals before you start running. Of course, pretty much every runner who calls me for a second opinion consultation on the phone or on Skype is trying to figure out how to run sooner, not later. Nobody really wants to wait months and then get an MRI just to be absolutely 100% sure it’s safe to start running. So that brings us back to Kelly’s question. She mentioned that she wants to run because she wants to qualify for Boston. She also mentioned that just trying to figure out whether or not it’s worth spending the money to get an MRI. So based on all that it seems like what she really needs to know is how is her money best spent to get her back to running as quickly as possible.
It sounds like her doctor has already confirmed she has a bone issue, in the form of stress fracture, because he noted some evidence of healing on the x-ray. The X-ray evidence of healing can be several different things. It can be a little bit of swelling between the bone and the covering of the bone. That just looks like a shadow around the area where there’s a stress fracture.
But there can also be a big lump of bone visible on the x-ray. In that case, the stress fracture has been healing for some time and there is actually what we call a bone callus around the stress fracture. The bone callus is a hard lump and it is structurally supporting the fractured area. That shows us the stress fracture is a long way along its course of healing and presumably fairly stable.
But if there is evidence on x-rays that the stress fracture is healing it doesn’t seem like the doctor is likely ordering the x-ray to just rule out a stress fracture altogether. It just wouldn’t make sense. Given that there is some evidence of an ongoing healing process on the x-rays it also seems safe to assume that if you get an MRI there is going to be inflammation within the bone that the radiologist will read as a stress fracture. The radiologist isn’t going to give you any clear indication of how far you are along the healing process.
The fact is MRIs are expensive. If the hospital or imaging center bill your insurance for the MRI it will likely cost a couple thousand dollars. If you’re lucky and you can get one for a relatively low cost by paying cash it still but probably cost at least $500. Here in San Francisco I having a good relationship with a great outpatient imaging facility where I can order your MRI and you can walk in and get an MRI for about $500. But still, that’s
500 bucks.
If money is the issue, and money is limited, you may be better off spending that same money on a bone stimulator instead of an MRI, which really is just going to tell you what you already know.
Keeping that in mind you probably want to call or email your doctor and ask several questions. I’m going to outline all those for you here. But don’t worry don’t have to write them down. Just go to the Show Notes page for Episode #68 and download the “MRI Questions to Ask Your Doctor.” It’s free.
Can you do an ultrasound exam really quickly, at a lower cost than the MRI right here in the office today?
What would you see on the MRI that would convince you it is safe for me to run today?
If that doesn’t show up on the MRI now, do I have to get another MRI again in a few weeks before you will let me run?
Without an MRI, how would you be able to tell when I can safely run? You have to remember that MRIs are relatively new technology. People have been getting injuries for centuries. We didn’t make them take a year off of running.
Sometimes is better to go old-school with the evaluation process and then come up with some very creative strategies to reduce the stress you can get back to running sooner.
This is exactly the sort of thing that I do with runners you call me for second opinion on Skype or by phone. I try to figure out exactly where they are in their healing process and then help show them how they can evaluate their response to increasing activity without making a stress fracture worse.
What are the signs (other than MRI) that stress fractures have healed enough to run?
Absence of bruising
If you have a question that you would like answered as a future addition of the Doc On The Run Podcast, send it to me PodcastQuestion@docontherun.com. And then make sure you join me for the next edition of the Doc On The Run Podcast!