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[maximize]

To bring this discussion even one step further, if you DO have an internal femur lengthening procedure, develop a valgum deformity, and notice in 2-3 (or 10) years your knees are feeling sore, particularly to the lateral compartment, you are not completely screwed. A femoral wedge osteotomy (removing a wedge of bone from the lower femur to reangle it) may straighten the knee. Doing so can at least partly reverse the damage being caused by the valgum to the lateral knee compartment. But it is not pleasant or easy.

Ref: http://emedicine.medscape.com/article/1251668-overview#aw2aab6b7

"The rationale of corrective osteotomy is to unload the diseased lateral compartment by overcorrecting the pathologic malalignment of the lower extremity and to facilitate the reparative capacity of the knee joint once it is mechanically unloaded. The regeneration of articular cartilage and proliferation of fibrocartilage has been demonstrated during repeat arthroscopy, compared with previous arthroscopic findings in knees that were overcorrected by an osteotomy.[39, 40, 41, 42, 43, 44, 45, 46]" (ie. Damage caused to the cartilage by genu valgum can repair itself to an extent once the genu valgum is corrected.)

"Valgus malalignment of the knee joint is often corrected by a distal femoral osteotomy, with a medial closing wedge fixed internally (see the image below)... It has been shown to be safe and effective in correcting deformity and slowing progression of knee arthritis. To bring the knee joint line parallel to the floor by osteotomy, the deformity usually has to be corrected in the deformed distal femur itself.[16, 42, 49, 52, 53, 54, 55, 56, 57, 58, 59, 60]" (ie. To properly fix this misalignment, you need to go back, chop off the lower end of the femur, take a small wedge out to reangle it, and then refix it together. Pic below. This will possibly cost you a small amount of height gain from all the sawing, plus it's another major operation you'd need on both sides, if someone is willing to even provide it to you for only a few degrees correction and after cosmetic LL sugery.)



The suggestion above of correcting it via tibial varusing during a tibial Ilizarov could also be valid. But then again, you need to do both upper and lower legs, and tibial Ilizarov isn't that much fun from what I gather. And again, you are opening yourself up to risk that your surgeon will not control the device precisely enough to give you the exact correction you need.

Seems better to me to just pursue methods of LL that don't (or at least more minimally) shift the axis of the hips/knees/ankles to begin with.

[YellowSpike]

I think those of you with bowlegs (genu varum) are lucky. You might be the only "ideal" candidates for internal femurs in terms of potentially improving rather than worsening the mechanical axis.

Yeah I was fairly significantly bowlegged before (not ridiculously so, but it was noticeable if you looked enough at it), and now my legs are perfectly straight. And, I don't have x-legs when I stand with my feet apart. So if anything, I'm hoping the realignment has helped me a bit.

[maximize]

For anyone with unoperated, natural, well aligned knees who doubts or wonders how a subtle valgum would affect their hips/knees/ankles/gait, I suggest a simple experiment. It's not perfect, but I think it's the best you can do without actually operating on yourself.

Pick up a pair of cheap dollar store foam sandals. Cut a small wedge of foam off from the sandals to run along the whole outside of your feet like this:





Put the wedging material in your shoes. Now walk around with that for the next week or two. Maybe the next month or year. Do that and then report back how natural your gait now feels, and how naturally or not your knees and ankles hinge.

I just tried it for a few minutes, and I could be mistaken but I think I might have been starting to develop the same kind of subtly "strange" looking gait we have seen from some lengtheners that have done internal femurs. eg. Like the video that was posted ITT a bit earlier. Not sure. Could be placebo. It certainly feels different though.

I'm not suggesting performing this experiment will accurately emulate what happens from the shift in axis caused by internal femur lengthening surgery. The only thing that can show you what that would feel like would be to actually get the surgery and see. But I think it should make it evident if you try it that even subtle valgus stresses/deviations can change the mechanics quite noticeably.

On the other hand, if you have already had internal femurs done and are experiencing knee/ankle pain, perhaps you may wish to try the opposite and apply a medial wedge (to the inside of your foot) to see if it helps relieve your discomfort like this:



If it helps, custom orthotics can be designed with a medial wedge like this, and it may be the simplest, easiest method to manage any discomfort caused by the valgus shift.

[Wazzup]

Damn. You are making some good and important observations!

 I was planning on lenghtening my femurs only 6cm because I was already concerned on biomechanical functionality due to the tibia to femur ratio and proportions.

I was sure I wanted to do femurs because i guess using aomething like 2cm insoles or boots would helph that ratio..

Unfortunately and from what you are saying using insoles or boota wouldn't make a different when it xomes to the problem you are pointing out... Or would it?

There god I will only do it in 4-5 years time when ll is way more expensive but more studies have been done.

What are your thoughts when it comes of using insoles to helph this voth cases after lenghtenig femurs? Would it help both, one of them or none?

Well at least when it comes to tibias using insoles or boots would only make things worse

[crimsontide]

this is getting tiresome and obessive

ask a surgeon.... a real dr what they think is best..

[maximize]

I just had another thought brainstorming solutions for this subject that I am finding exciting. In fact, it could be groundbreaking. Let me share. I hope you will find the concept as intriguing as I do.

Current Internal Options:
Most of us would prefer to lengthen via internal fixation (eg. Guilet, Precision) for the speed, safety, and lack of wearing an external cage.

As stated, a internal tibial lengthening procedure should theoretically maintain the anatomical axis perfectly if well done. But when I was reviewing the journal articles on this, I was seeing even with this approach there can be slight deviations. It's understandable why, given that the exact angle of distraction will depend on the angle of the rod in the tibia. Drilling the rod into the tibia isn't exactly a perfect science, and a lot of tibias have a slight "S" curvature to them that could slightly alter the angle as the rod goes in. The point being, not even internal tibias will probably be "100%" perfect every time. But they should be pretty damn good. Tibia lengthening is slow though, and I'm not confident that a deformity couldn't occur to the fibula during distraction affecting the lateral ankle.

By contrast, internal femurs are fast, effective, and safe. Since only the femur is involved, there is minimal joint complexity. It's much easier to gain mechanical access to drill the hole for the device to be inserted (no patella, peroneal nerve, no fibula to fix, etc), so surgically it's as simple as can be. The problem is as stated, this approach guarantees that you will have axis deviation. Perhaps this may truly be a nonissue for many of us. But I think all of us would prefer not to have this axis deviation if there is a way to avoid it.

So what's my proposed solution? How can we improve the cutting edge of modern internal femur leg lengthening? Well I sort of brushed against the solution a bit earlier and I just connected it now. Some of you may perhaps think this is crazy, but bear with me. I think if you consider it fully, it may make a compelling argument.

Without further ado, here's my great big new idea ... Surgeons, if you like the idea, please feel free to apply liberally... Just please don't claim to name it after any one of you if it catches on... And please do PM me for co-authorship credits if you publish on it...

NEW IDEA - Internal Femur Lengthening Followed by Distal Femoral Opening Wedge Osteotomy (During Nail Extraction):
In my proposed new approach to lengthening, internal femur lengthening is first performed as usual. In this way, you get all the benefits of rapid growth, safety, and avoiding ankle/equinus/peroneal/patellar problems. You rehabilitate from this femur lengthening as usual for 1 year. When you reach the 1 year point and are ready to have your nail removed, final full leg sets of xrays are taken while standing in natural anatomical position. These xrays are then used to calculate and assess the degree of post-op genu valgum (or perhaps paradoxically varus if you have an abnormal alignment to begin with). The deviation is carefully assessed and measured for.

Then when you go in for your nail extraction, in addition to taking the nail out, if the misalignment is deemed significant, the surgeon performs a carefully calculated small bilateral distal femoral opening wedge osteotomy to perfectly correct it:




Re-alignment could be verified for perfection in the OR during the osteotomy with temporary pinning and portable xray before final fixation is applied. You can then get a rapid safe internal femoral lengthening, combined with a totally perfect (to the surgeon's skill level) correction of your axis bilaterally. Furthermore, since it's an opening wedge osteotomy, you don't lose a millimeter of height. In fact, you may actually gain a tiny bit more.

This adds one extra layer of surgery, but since it's done at the time of nail extraction, you're under anesthetic already anyway. The osteotomy procedure alos doesn't appear to be that complicated. Furthermore, it's rigidly fixed, so should be back to full normal weight bearing shortly post op. It could probably be optional whether or not you want the fixation metal for the osteotomy removed at a second follow up.

This could even provide superior alignment of the axis compared to internal tibias, because if you get a mild deviation during internal tibias, there is no way to correct that at the end. This approach offers a way to get a rapid femur growth and then completely fix any degree of misalignment no matter how great, as long as the finishing osteotomy is well planned and performed. In other words, if you can accept the idea of the osteotomy during nail removal, I think it's pretty much a perfect solution for rapid, safe femur lengthening while maintaining neutral knee/ankle axis alignment.

I'm pretty happy. I think this is an awesome solution that should be offered electively to any person who wants it done. I think this would be a great approach if a reputable surgeon could be convinced to consider it. I hope if they like it, they won't mind that it wasn't their idea first.

Also, I wasn't going to say this, but if it helps add weight to further consideration of this idea (which I think could potentially be quite good), then I will say it. I am a real doctor. Not a surgeon, but yes a real doctor. During med school and residency, I assisted in the OR for numerous hip replacements, knee replacements, arthroscopies, etc., did tonnes of ortho exams, joint injections, casting fractures, etc., and assisted consults in numerous orthopedic surgery offices. So I have at least some limited background in orthopedics.

[KiloKAHN]

I'd still do external tibias all over again before doing them internally. At least if you go to a doctor that offers a Taylor Spatial Frame or a six-axis correction system like a hexapod, your doctor can do a perfect realignment with the computer software once the lengthening is complete.

[Wazzup]

To be honest when I was making my previous post I thought about it. But not like you did. Mine were:

1. doing the Distal Lateral Femoral Opening Wedge Osteotomy at the time of the LL operation. It was stupid because we didnt know how much we were going to lenght.

2. Doing long time after. As you said before 2-3 (or even 10) years later

The way you said it was just perfect. Doing it when removing the nail! But what would be the new risks? The new price?

[Wazzup]

Well in the old forum they already wrote about this. The name of the topic was: Bow Legs & Knock Knees Correction

[maximize]

Well in the old forum they already wrote about this. The name of the topic was: Bow Legs & Knock Knees Correction

Just read that thread. It looks like it was just a very general discussion of how major varus and valgus deformities can be corrected in orthopedics. It's not really touching on our specific points ITT.

I'm still laying claim to the idea of performing distal femoral opening wedge osteotomies as part of routine practice during nail removal for internal femoral leg lengthening.

If this catches on, remember, you saw it here first.

[maximize]

I'd still do external tibias all over again before doing them internally. At least if you go to a doctor that offers a Taylor Spatial Frame or a six-axis correction system like a hexapod, your doctor can do a perfect realignment with the computer software once the lengthening is complete.

KiloKAHN, I just read your thread. Wow. Thanks. I didn't even know such advanced external tibial fixation devices existed. Based on that I think the two best approaches for preserving/correcting axis during leg lengthening could be in order:

1) Tibial Taylor or Hexapod - If you can wear it 8 months to lengthen 6 cm and don't mind the pins/apparatus.
2) Internal Femurs with Distal Femoral Opening Wedge Osteotomies (DFOWO) - Faster with bigger gains, and still with good post-op alignment, although as proposed above, this option doesn't technically exist yet.

I would guess the Tibial Taylor/Hexapod approach would be slightly superior in terms of final alignment given that they can be fine tuned by computer. With the femoral method I suggested, the surgeon's hands are the final arbiter of your alignment, so there is opportunity for human error. Additionally, the Internal Femurs with DFOWO approach will still by design force a mild probably 1-2° abduction (opening) of both hips. I don't think that would cause any issues at all, since the hips are freely ball-and-socket. But this abduction is avoided with a strictly tibial approach, so from a purist perspective on alignments, a computer assisted external tibial approach might probably be most ideal (though very slow).

Do you know anyone using the Taylor device for cosmetic leg lengthening? It looks more advanced than the Hexapod.

[KiloKAHN]

I don't know of any diaries where a TSF was used. They're quite expensive so I'm told they're not usually done for simple lengthenings. You might end up paying around the same price for a TSF as you would for an internal device.

As far as I know the hexapod does the same exact thing, according to my surgeon, who's used the TSF before when they were donated to him from a UK clinic. I'm guessing the main difference is the material it's made out of. But they both use computer software and are six-axis so the result would be the same.

[maximize]

I've looked a bit more into the subject of using distal lateral femoral open wedge osteotomies to correct the valgus shift that can be induced by internal femoral lengthening.

For anyone that's interested in details, a full article is here describing the procedure in depth:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2899363/

To illustrate again what a valgum looks like (a, b) and what a distal femoral opening wedge osteotomy can do to recreate an ideal alignment (c), here's one pic from the linked article:



Here's a small diagram showing the hardware:



The main points I've learned from reading about the procedure are:

• This can be an exceptionally precise procedure. The angles are all planned out in advance. A small metal spacer (eg. between 5-17 mm) can be introduced to the edge of the osteotomy to guarantee you are getting the amount of wedging you want.
• Primary risk is incurred during the "splitting" process to open up the osteotomy. This risk is that if this is not done cleanly/well, the bone can just fracture straight through. Not sure what the probability of this is. Probably very low in healthy bones. But obviously you'd want someone who's done this before operating on you.
• Big point: In order to protect the alignment post-osteotomy, it's suggested that are completely non-weightbearing for 4 weeks, and 6-8 weeks total to get back to full normal weight bearing, or as x-rays indicate consolidation has occurred.
  

My final impression is that this procedure is the definitive solution to the potential problem of valgus shift during internal femoral lengthening. It could be best applied by getting the internal femurs done and then rehabbing for 1-2 years. After 1-2 years, if the valgus is significant/bothersome (or the individual worries it will in the future), nail extraction and distal femoral opening wedge osteotomy are booked to occur during the same procedure.

I don't know what Dr. Guichet's or Dr. Paley's experience with performing this kind of osteotomy would be. I'm guessing they would be capable of performing it, but probably haven't done it much before since it's not their field of expertise. If so, if it was me, I would probably see if I could get another surgeon with expertise in this to attend during the nail extraction and perform it with Dr. Guichet/Paley assisting.

It's a tossup for me between going this route vs a comparatively noninvasive approach like tibial Ilizarov with Hexapod.

The internal femurs even with time for the corrective wedge osteotomy is probably going to be faster. With Guichet, it's almost exclusively weightbearing. The femur approach also allows you to still wear heel lifts for another 1-2 nonsurgical inches without it looking ridiculous. The main downsides of this approach are first that the realignment osteotomy will require two months of downtime. Plus then you've got permanent hardware in your knee, or you have to go back for a third operation to remove it. It also involves a lot of drilling/cutting into the femurs.

By contrast, the Ilizarov with Hexapod is comparatively noninvasive with very little cutting/drilling. I also personally prefer the look of long tibias. But it's very slow for comparable gains, such that even with good progress, at 10 months you can still have your frames on. Plus you have to spend 6-8 months under medical supervision in a foreign country.

It's a tough decision. Both approaches should maintain the hip/knee/ankle axis well. But they are very different pathways. Thoughts?

For my own part, I think I am leaning towards internal femurs, perhaps weightbearing with Guichet, and then following that with a slight realignment osteotomy in 1-2 years during nail removal if needed.

[Sean Connery]

You don't think the wedge will make it easier to get femur fractures or anything? It looks like they'd be more sensitive to that sort of thing when you cut a bit of the bone out.

[maximize]

You don't think the wedge will make it easier to get femur fractures or anything? It looks like they'd be more sensitive to that sort of thing when you cut a bit of the bone out.

You are not actually cutting a bit of the bone out. Cutting the bone out would be a "closing" osteotomy. That would cost you height. The beauty of the "opening" osteotomy, is you are doing just that - opening up more space, and thus you will actually gain at least a few more mm through the procedure.

Here is a picture of how the "opening" is done:



As long as everything is well fixated together when done, you should ossify the few mm gap on your own within the 8 weeks or so they suggest for sufficient recovery. But that is why you must be nonweightbearing for at least 4 weeks post op.

In the case of a big valgus deformities, where you need more than 7.5 mm wedging, they suggest using a small bone graft from the iliac crest (where bone grafts are usually harvested from) to fill the gap and prevent nonunion. Below 7.5 mm it depends who you ask they say whether there is still benefit from grafting or if it is fine to just leave it open with just the metal spacer and it will fill easily enough with bone on its own.

I expect it should be fine for most of us with no graft at this small a wedge, because as a wedge, it will start to fill from the narrowest aspect and continue outwards from there. I suspect a graft would only be universally necessary in, for example, an elderly woman with poor bone/healing quality.

I'm not sure which category we'd typically fall into in terms of how much correction we'd need. It would be easy enough to calculate though with some simple math though, and I will do this at some point in the future.

[Overdozer]

I had a thought...

You're showing the effect of mechanical axis deviation from norm, when someone is standing with their feet together. So as we've figured the tibia is angled 0 degrees, but only when standing with your legs closed (obviously deviatons also occur). When you spread them apart, tibia gains more angle. So what happens when you lengthen femurs internally is that you just have to spread your legs more to put feet together now. Where I was going with that... You don't usually see people standing with legs completely closed feet together, right? That means their tibias are already angled and in comparison with someone who has done internal femurs, it would be no different angle, because you're standing with your legs apart anyways. Now you could say: it's walking that matters, not standing. Lets think about that...




So they're walking with their legs spread, knees not connecting together, feet are more spread in the first video.


Now imagine if they lengthened 7 cms in their femurs along anatomical axis. As their feet and knees aren't being put together, which should btw mean that they are walking with an angle in their tibs as is, they shouldn't feel too much difference after LL. What do you say? I think your mistake was basing all your assumptions on a model of someone standing with their feet together, which is when the tibias are angled 0 degrees.

[maximize]

I'll clarify a bit:

The mechanical axis is defined as a straight line going through the femoral head and the middle of the ankle joint. In a well aligned leg, when you draw a line connecting the middle of the femoral head to the middle of the ankle, you will also go straight through the middle of the knee:



This alignment is important, because having it means the primary points of load bearing of the leg will pass weight and hinge efficiently (femoral head, knee, ankle). According to eMedicine "the mechanical axis averages 1.2° of varus". This means the line that goes through all these weight bearing points when you are standing in a natural position is for most people on a tiny 1.2° varus tilt relative to the perpendicular.

If you start with a good mechanical axis and then lengthen along the axis of the femur, you will inevitably throw these three points of alignment out of wack into a mild genu valgum (as per my diagram in the OP). You will be misaligned when standing in any position and even when walking. Whether you will notice this or it will cause damage to your joints may vary from person to person. I posted explanation and evidence for why I believe it has the potential to be a significant long term problem on page 4.

The only way I can see to properly get the alignment back after such internal femoral lengthening is to do a distal femoral opening wedge osteotomy to the lateral aspect of the femur during follow up as described above. (Or the other valid option for maintaining the axis is to avoid the femurs altogether and do, for example, internal tibias or Ilizarov tibias with Hexapod. But as discussed, those options both come with other challenges.)

I can perhaps put together some proper Photoshops in the future if this doesn't make it clear.

[Overdozer]

I know what mechanical axis is. I don't think you understood what I was talking about. In fact, you ignored all of the points I've made.

Initially you were claiming that after lengthening femurs along anatomical axis, "spacing feet naturally now creates angulation to joint lines". But you're looking at only one position (feet together) and also ignoring the fact that you're going to have the very same 'angulation to joint lines' if you stand in ANY position other than the initial one with your feets closed. Let me show...


Here we have someone standing with their feet together, no angulation to joint line, right? We have a perfectly straight line. But then he spreads his legs/feet apart...



And now he has the very same angulation in knee joint, which he'd get after IFL. And I could also argue that this position is more natural and usual, than the one with feet together.

[maximize]

I think the exaggerated nature of the diagrams I used to demonstrate this are throwing off the discussion. Let's stick to more anatomically correct diagrams. This diagram shows the natural alignment of a good mechanical axis with the feet naturally apart as one would generally stand (with the ankles pretty much directly under the femoral heads, and the knees lining up along that axis perfectly with their joint line perfectly horizontal):



Do you recognize that if you lengthen the femur along it's anatomical axis, when standing with the feet similarly spaced so the ankles are still under the femoral heads (as they must be for natural stability and weight bearing), you will no longer be able to draw this straight line through the exact middles of the femoral head, knee, and ankle?

[Blackhawk]

There is a lot of good info in this thread.  But there is another variable to consider.  How does ballspan affect the mechanical axis and does it eventually cause joint pain?

[Uppland]

There is a lot of good info in this thread.  But there is another variable to consider.  How does ballspan affect the mechanical axis and does it eventually cause joint pain?

The issue of the anatomical ballspan is a complicated one that frequently split the scientific consensus. Many questions remain before a unified theory about balls can be presented: do we measure ballspan in cold or warm temperature? What about hairy balls? Are the balls balls beyond the balls and just how many balls are there?

One thing is for certain though: with a proper ballspan, there is no limit to how far you can go. Godspeed and may your balls never shrink or drop below your knees.

[Blackhawk]

The issue of the anatomical ballspan is a complicated one that frequently split the scientific consensus. Many questions remain before a unified theory about balls can be presented: do we measure ballspan in cold or warm temperature? What about hairy balls? Are the balls balls beyond the balls and just how many balls are there?

One thing is for certain though: with a proper ballspan, there is no limit to how far you can go. Godspeed and may your balls never shrink or drop below your knees.

Lol!!!  I agree, the issue of ballspan is indeed a complicated issue.

[maximize]

I just want to provide a brief update on my thought process regarding this issue (in the interest of continuing to think out loud for whatever it's worth to anyone else).

I've looked at the distal femoral opening wedge osteotomy a bit more, and I know now why it's not offered. It's no small surgery. You're looking at large, deep incisions (at least 5-6" long), and significant tissue spreading to good exposure of the bone for plating. And then you've got that hardware in you which could cause pain by itself. Going back to remove the hardware is going to be equally invasive and risky.

So basically the best options as I see them in LL are:

1) Get internal femurs and live with the valgum shift. Realize it could put you at risk for chronic joint pain secondary to axis misalignment. But there's no way to know if it will for sure.

or:

2) Get external tibias via Hexapod or Taylor Spatial Frame. Internal tibias are an option too but with the risk of anterior knee pain like MDOW has secondary to patellar tendon or bursa damage.

Unless my preop xrays show a major varus to my knees, I'm almost certainly going to go with the second option. It's slower and more painful in the short run, but done by a competent doctor I think it has the lowest probability of any LL surgery of causing chronic joint/nerve/pain problems.

I'd rather take an extra few months to get my lengthening done that way and suffer in the frames than take a shortcut and pay for it in 5-10 years (and for the rest of my life).

[682]

Bump for a very interesting post and to bring to peoples attention!