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[maximize]

I just finished reading a few of the cases that people have attacked Betz or Guichet over in this forum. One of Betz's very bad cases was a nonunion due to infection that reportedly was not identified or treated correctly. The other bad cases for each I have seen have all been simple nonunions.

We know obviously nonunion is the greatest risk for these mechanical nails because they cannot close back down if you open them too fast.

The question I have is: Why can't this risk of nonunion be controlled with slower distraction?

I read on either Guichet's or Betz's website (not sure which one) that from their perspective one of the advantages of their nails is because the ratcheting is predictable, you only need x-rays once a month. They say you need fewer x-rays because you can measure the progress by clicks, not by x-ray. But to me this would be insane. If you were only getting monthly x-rays and distracting at 1 mm/day, you would only be getting an x-ray every 3 cm of distraction. If you do not have callus forming in that gap even just that gap could cripple you and ruin the procedure if you do it too fast.

My inclination would be:

• Distract 1 cm at a time.
• Every 1 cm, get an x-ray.
• If the x-ray shows inadequate callus in the gap, do not proceed further.
• Use PEMF/LIPUS to stimulate constantly and until the gap starts to fill.
• Repeat until done.

A 1 cm gap should fill almost universally for anyone (if it won't there is something medically wrong with you and no LL will likely work). But if you create a 5-10 cm gap with nothing bridging it or go so quickly the tissue can't maintain a connection, obviously you will then be totally fked.

The only challenge I would imagine with that protocol is you might risk premature consolidation and not be able to ratchet further. Also I have seen pictures where sometimes the outside/inside aspect consolidates or develops callus faster than the other - in those cases it would be hard to know if you should keep going or waiting. You need bridging all around to be safe but if one side hardens you won't be able to ratchet.

Premature consolidation is a much lower risk than nonunion. You can always go back in the OR to get it rebroken. You can do that a dozen times and it's no big deal (as long as no infection is introduced during the rebreak). On the other hand, a nonunion can ruin your life. So watching closely, going slower, and risking premature consolidation seems far better than risking nonunion.

What do you think is actually happening in these cases? Are people just distracting way too quickly/far and not checking the x-rays?

In most LL aren't the surgeons checking for callus every 1-2 weeks to give you the okay to go further or slow down (or stop)? Or are people blasting ahead blindly for 8 cm like a runaway train with no x-rays or nothing showing on the x-rays and then surprised when there is no bone in the gap at the end?

Thanks for any thoughts.

[maximize]

I went looking for answers on how the distraction rate ought to be determined and this is the best reference I could find with a clear answer:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3364349/pdf/11832_2012_Article_391.pdf

Plain  radiography—weekly  to  bi-weekly  during  distraction,   monthly   in   the   consolidation   phase   and   3–4 monthly   after   consolidation—is   still   the   most   useful methodology to monitor the fragment alignment, as well as the quantity and quality of bone formation [60]. More than a  typical  central  4–6-mm-thick  radiolucent  zone  corresponds to an exaggerated rate of distraction and vice versa [38,92,108–111]. The assessment of the shape, type and quality  of  regenerate  bone  may  be  helpful  to  predict  the stability.

In other words, you should be getting x-rays every 1-2 weeks and there should always be a 4-6 mm thick radiolucent (no bone visible) gap between the fragments during distraction. Any more and you've gone too fast. Any less and you've gone too slow.

Here is an example diagram of what they mean (FZ should always be 4-6 mm):



So basically as long as you are watching the callus formation closely with x-rays there should be clear indicators of whether you are going too fast or too slow.

If I were to guess, I would expect most of the cases of nonunions were not getting regular x-rays or no one was looking at them seriously. If they were, this sort of thing should have been clearly recognized and addressed no matter which distraction method you are using.

If any of the chronic nonunion patients are still around and reading this, could you comment on whether you think that was the case for you? Or was there something else you think contributed to it?

[chasing_higher_dream]

This is fantastic article @maximize. Thanks for doing this research and for the information.

[RealLostSoul]

Thanks for sharing. I think getting xrays is everyones duty during lengthening just get biweekly xrays and I think you should be okay. I bet a lot of bad outcomes with these doctors comes from them being allowed to go home and neglecting monitoring their bone regeneration rate.

[Antonio111111]

This is something I've been thinking of as well. Why so many non union cases with betz. I think op is correct.

With betz your allowed to go home after 2 weeks and lengthen at home. It raises risk of patient clicking too much and neglecting xrays. It's the flexibility offered by betz that ultimately can make him look bad with non unions caused by patients.

What about the ratchet mechanism. It looks like rods need to twist to extend. So the 2 pieces of cut bone need to twist against each other for it to work. This would also twist the new callus/soft bone making it weaker? That's my guess. Maybe this also raises non union risk.