#728 6 Stages of fracture healing in runners explained - DOC

#728 6 Stages of fracture healing in runners explained

How long is each stage of fracture healing when you have a broken bone? Well, that’s what we’re talking about today on the Doc On The Run Podcast.



Everybody who has a fracture wants to know when can I actually run. It’s not that simple. Number one, it really depends on when you have enough strength in the bone that you know it will withstand the forces when running without it breaking again, obviously. But it seems like that’s not so obvious to all the people who post questions and send me emails and comments.

The reality is, is that it depends on what you had done. It depends on your physiology, and it depends on these timelines. But it does wholly depend on these timelines like everybody wants to think. We’ll talk about this in more detail.  

There are basically six stages of fracture healing and what is written in textbooks like the Sonography of Fractures textbook, for example, it talks about six very specific things. This is the kind of stuff were taught in med school and this is what people want to think means when you start running, but that’s not true. We’re going to discuss as we go through this.

Stage 1

First thing in stage one. So, break the bone, right, and stage one is basically from day Zero to day 10. What that means is that you break the bone in two pieces. So, what happens, well, you get a blood clot that forms. In that early phase, you have blood vessels that are in the bone and when you tear those blood vessels because you broke it, it bleeds. And so, you get a blood clot, it bleeds in between here, and it forms a blood clot between the two pieces of broken bone. And that starts to change over those 10 days, forming what we call a hematoma, which is a firm congeal blood clot. That’s the first phase.

Stage 2

The Second phase, well, obviously starts somewhere around days 11 and 19. This is where you get an initial soft callus. So, I’ve talked about this a number of different episodes, but basically, you’ve got your fracture here and day 11 and 19 that blood clot actually starts to change. So, not only does it have the blood in between there, but you start getting some actual collagen fibers and fibrin. They’re strands of collagen that basically form within the blood clot and that actually starts to kind of hold it together. Like if you look at duct tape, for example. It has fibers in it to make them a lot stronger. It starts to become a more stable glue during this period of initial soft callus formation where you have fibrin. So that’s soft callus with the fibrin strands in there.

Stage 3

Stage three goes on from about three weeks until a little over a month. So, stage three, what happens is that you have a bridge callus, and this is where again you have your bone here fractured, and now what you’re getting is that instead of just having these little strands of collagen kind of holding it together within this glue, you start to get some mineralization. In this time is the earliest it’s going to actually begin to show up on an X-ray.

During these phases you can actually see this on ultrasound, and you can see this progression better on ultrasound than you can on X-rays. So, it starts to become stronger because you’re starting to get some minerals deposited in there, in the fracture site.

Stage 4

Stage four from day 36 to 49, where you have your fracture here and what’s happening during stage four is where you’re really getting a drastic increase in the strength of the bone because now, you’re actually starting calcification.

So, where it’s fractured, where you’ve had that blood clot, where you’ve had the soft callus formed, not only do you have the fibrin kind of glue holding it together, but now you’re actually starting to get the calcium deposit in there that shows up on X-rays, what looks like actual bone. And so that’s actually where it’s kind of welded together instead of just glued together.

It’s getting a lot stronger in this stage. Now at this point, we know that you’re okay to run if you see this on an X-ray during stage three, that’s different. So, stage three is really kind of a critical phase and what’s going to happen I think is most people are going to watch this and they’re going to incorrectly think that because I said this is the critical phase or stage three, that they’re going to think this 20 to 35 days as long as you make it pass that’s okay to run. Not necessarily but it is the critical phase because during that time, either it becomes stable and becomes way more solid enough that it actually starts to mineralize during that time, or it starts to become a non-union where it’s not going to heal.

This is also the time when people make a critical mistake. It’s where they actually force too much activity, and it starts aching again. And now they’re actually really delaying the healing of the bone and they’re really putting themselves at risk of having to have surgery later because if it comes non-union. That’s what I mean by this being the critical stage. That’s the most important is getting through that part. That’s really the most important thing is to get past this stage and that does not mean just make it to 20 days or just make it to 35 days. That’s not what I’m talking about.

But if you get through that, you get to stage four, then we actually see this on X-ray. The other reason this is important is that most doctors will wait until this happens before they’ll let you do any activity at all. That’s not what I necessarily recommend. So, for most people that I talk to, I try to figure out how to start an activity that gets you exercising before you actually pass a critical set stage. How can we maintain your running fitness during all this time up to that, so that when you get to this stage, you’re actually really ready to run, not just trying to get off the couch. That’s the most important thing for injured runners, I think.

Stage 5

Stage five is when you’re from day 50 to 89. During this phase what happens is when you’ve had the fracture, not only do you already see it on X-ray, not only all that fibrin stuff is starting to get resorbed but actually what you get is a whole lot of extra thickness of what we call hard callus that is visible oftentimes is a lump on the X-ray, right where the fracture was.

That big thick callus is very, very stable and so the callus thickness during the stage five, actually, not only does the bone get thicker but where you also have that you won’t see on X-ray, but you could see on ultrasound is that you’ll have this area of fluid, basically here and here that you can see on ultrasound, where you’ve had fluid over here, where all this healing process is taking place, during the soft callus phase until it starts to actually mineralize. And then when you get to this phase, if you do ultrasound, that layer of fluid starts to go away. It gets very, very thin. So, that’s one of the reasons we can know when I am looking at the ultrasound unit that that is actually changing.

Stage 6

Stage six is really mostly remodeling. So, I think this can go on for like up to a year and a half personally. But what’s written in the textbooks is from day 90 to 140. And what’s happening during that time is that this callus is getting thinner at that point. So, it’s still going to be there. You are still going to have a lump but where you’ve have had that fracture lump,  the thick dark line where you’ve had this fracture so visible on the X-ray, gets very, very obscured. You start to see these trabeculation lines across the X-ray and this callus gets thicker.

So, what’s happened during that phase is you have the balance of two cells called osteoblasts and osteoclasts. And basically, one of them goes through and eats these channels of bone and then another cell comes down and lays down tubular sort of well formed, much stronger bone, kind of like a whole bunch of like if you took a bunch of rebar and wire it all together. Well, if you do that it’s all going to be stable because it’s linear. That all those tubes are linear, and they’re all wrapped together much like the cables inside the Golden Gate Bridge or something.

But basically, you get all this remodeling going on during that phase where the bone becomes significantly more stable, a whole lot stronger and as a result, the lump of bone around it is kind of dissolved over time. Just because you have that callus does not mean, you know many years later, doesn’t mean it’s not completely healed. It probably is completely healed but it’s all about the amount of stability.

The really critical piece here is that you don’t just think that the timeline means it’s okay for you to run. That’s not true. You need to really be thoughtful about this. You really need to figure out where you are in this continuum. You have to do everything possible to maintain your fitness while you go through this process of healing a bone.

If you want to check more about stress fractures, I made a thing  for you. It’s a deep dive into metatarsal stress fractures and what it really means with injured runners and how you can navigate some of this better. You can get it for free, it’s at www.docontherun.com/stressfracturemasterclass.

If you enjoyed this episode, please like it, please subscribe, go check out stress fracture masterclass and I will see you on the training.