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Author Topic: What's the safe limit for femur lengthening?  (Read 2572 times)

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Jokerhastowait2022

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What's the safe limit for femur lengthening?
« on: September 21, 2020, 05:12:24 PM »

Hey there.

I was wondering what the safe limit for femur lengthening is, just like for tibia it's 5 cm, any ideas?
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Bane

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Re: What's the safe limit for femur lengthening?
« Reply #1 on: September 21, 2020, 05:50:33 PM »

This was discussed a while ago, but this website is constantly getting new members.

Doctors prefer to base safe lengthening measures based on the bone length. For the femurs, 30% additional is the max. However, over 20% and the bone regenerate quality usually starts to decrease. So 20% max for the femurs is often recommended.
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a

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Re: What's the safe limit for femur lengthening?
« Reply #2 on: September 22, 2020, 06:04:49 PM »

I'd say 7 cm, 7.5cm max. It depends on the individual, for me it's 7cm. Some people would say 5 for the max recovery, some'd say 6; I say 7.

5 is for the maxEST recovery
7 is still in the safe zone but it might worsen your bio-mechanics. I think 5 cm won't hurt anyone (on femurs). But 7 is still safe.
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ghkid2019

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Re: What's the safe limit for femur lengthening?
« Reply #3 on: September 22, 2020, 07:48:34 PM »

8cm is very common and pretty safe with an illiotibial band release. The less you go the better the recovery obviously. But plenty of people do 8cm no problem. So in this equivalence, 8cm for Femurs is like 5cm for Tibias.

To determine the safe limits for femur, just use the PRECICE nails mechanical limits for guidelines.

Tibial nail: 5cm (we alrdy established that it can do more but Achilles tendon gets buttraped as OP knows)
Femoral nail: 8cm (mechanical limit)

« Last Edit: September 22, 2020, 08:59:44 PM by ghkid2019 »
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short

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Re: What's the safe limit for femur lengthening?
« Reply #4 on: September 22, 2020, 08:04:39 PM »

To determine the safe limits, just use the PRECICE nails mechanical limits for guidelines.

Tibial nail: 5cm
Femoral nail: 8cm
This.
And safe limits are <= 15% of your bone-length.
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ghkid2019

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Re: What's the safe limit for femur lengthening?
« Reply #5 on: September 22, 2020, 09:01:31 PM »

Dunno why I included tibial nail in there. Both are 8cm mech limit but I should have referred femur only, as that's wat is relevant. My bad

And yeah ,15% of bone length is safe, any more and expect to be riskier. So it is ironic but a taller person doing CLL is actually safer than a shorter person. It's ironic but it is what it is-donald j trump
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MailGuy

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Re: What's the safe limit for femur lengthening?
« Reply #6 on: September 22, 2020, 11:42:59 PM »

From what ive read below 7 or 8 cm seems to have good safety
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BelowTheMean

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Re: What's the safe limit for femur lengthening?
« Reply #7 on: September 24, 2020, 02:32:13 AM »

I don't think it's necessarily "unsafe" to do 8 cm if your doctor signs off on it. However, you might lose more athletic function than with 5 cm. Personally I'm okay with that though, so I'm shooting for 8 cm.
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Journal (169cm -> 177cm) http://www.limblengtheningforum.com/index.php?topic=65617

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dreamingtall

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Re: What's the safe limit for femur lengthening?
« Reply #8 on: September 24, 2020, 07:47:42 PM »

Alot of veterans say 8cm is hard but its worth it in my eyes and when they say that I think they mean in terms of recovery time. So of course if you do 5cm inches its going to go by a lot quicker. An extra year of regenerating is worth it to me and most others
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Highest

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Re: What's the safe limit for femur lengthening?
« Reply #9 on: September 24, 2020, 11:46:20 PM »

Dunno why I included tibial nail in there. Both are 8cm mech limit but I should have referred femur only, as that's wat is relevant. My bad

And yeah ,15% of bone length is safe, any more and expect to be riskier. So it is ironic but a taller person doing CLL is actually safer than a shorter person. It's ironic but it is what it is-donald j trump

Then why do you keep saying limit of 5cm for tibia then going to say 15% is safe?
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ghkid2019

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Re: What's the safe limit for femur lengthening?
« Reply #10 on: September 25, 2020, 12:12:20 AM »

Then why do you keep saying limit of 5cm for tibia then going to say 15% is safe?

Because 5cm is a good generalization. People don't know their tibia lengths without an x-ray, so 15% is meaningless info. Both are good estimations. 5cm is for convenience, for most people it's a good guideline. If you have a 33cm tibia (if you're asian 168cm male, you have similar) 15% of that is 5cm. If you're like 6'3 and african descent, you can probably get away with 7cm tibia lengthening and still be within 15%.

The point is that both are good metrics, I say 5cm because that's what Paley saids. In many peoples case, 5cm is a good general estimate for the 15% metric.

I'm not a doctor anyways. The safe limit really is just the point where you don't overstretch your Achilles. Rozbruch saids 4cm, Paley saids 5cm, mahboubian saids 6.5cm, Dr. Xia saids 10cm+, sarin saids infinity, the best answer is the less the better, 5-6cm max wud be a good estimate for 95% of people.
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brondo

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Re: What's the safe limit for femur lengthening?
« Reply #11 on: September 25, 2020, 12:13:13 AM »

Does anyone know the approximate time it takes to consolidate at each of these stages? I read somewhere that it's 2 months for every centimeter to make sure that the bone is fully consolidated and the nail is ready for removal. Is this true? So for 5cm it would take about 2 months distraction, and 10 months consolidation.
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ghkid2019

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Re: What's the safe limit for femur lengthening?
« Reply #12 on: September 25, 2020, 12:16:33 AM »

Does anyone know the approximate time it takes to consolidate at each of these stages? I read somewhere that it's 2 months for every centimeter to make sure that the bone is fully consolidated and the nail is ready for removal. Is this true? So for 5cm it would take about 2 months distraction, and 10 months consolidation.

1.5 to 2 months for every cm, total, which already includes distraction. So 5cm would be anywhere from 7.5 months to 10 months total, starting from the osteotomy. Not 10+5= 15 months
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brondo

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Re: What's the safe limit for femur lengthening?
« Reply #13 on: September 25, 2020, 01:25:57 AM »

1.5 to 2 months for every cm, total, which already includes distraction. So 5cm would be anywhere from 7.5 months to 10 months total, starting from the osteotomy. Not 10+5= 15 months

Thanks, and at this point would you have your athleticism back, before or after (running, sports, lifting weights, etc.)?
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Hagane

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Re: What's the safe limit for femur lengthening?
« Reply #14 on: September 25, 2020, 02:16:56 AM »

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Bilateral tibia lengthening with Dr Gdalevitch 02/2023
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Hagane

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Re: What's the safe limit for femur lengthening?
« Reply #15 on: September 25, 2020, 02:19:19 AM »

Thanks, and at this point would you have your athleticism back, before or after (running, sports, lifting weights, etc.)?

assuming your religous with your rehab. most of it should come back quckly as soon as you stop lengthening.
once the nails are taken out then youll really start to feelgood
so lets say around 13 months from the osteotomy ( assuming no complications and nail removal at 12 months)
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Bilateral tibia lengthening with Dr Gdalevitch 02/2023
starting height approx 167cm ( morning height)
gained  55.55mm
End height approx just shy of 5 foot 8 ( morning height)

brondo

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Re: What's the safe limit for femur lengthening?
« Reply #16 on: September 25, 2020, 02:32:29 AM »

assuming your religous with your rehab. most of it should come back quckly as soon as you stop lengthening.
once the nails are taken out then youll really start to feelgood
so lets say around 13 months from the osteotomy ( assuming no complications and nail removal at 12 months)

Thanks
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MakeMeTallAF

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Re: What's the safe limit for femur lengthening?
« Reply #17 on: September 25, 2020, 04:56:54 AM »

Anyone know what is the average femur length for a 5'7 male? I'm trying to get an estimate of how long my femur bone is, I don't really know how to measure it.

Ideally I want to do 5 cm femur to get to 5'9 sometime in the future. Wondering what % that would be. Mainly concerned with soft tissues
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Highest

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Re: What's the safe limit for femur lengthening?
« Reply #18 on: September 25, 2020, 05:13:36 AM »

Because 5cm is a good generalization. People don't know their tibia lengths without an x-ray, so 15% is meaningless info. Both are good estimations. 5cm is for convenience, for most people it's a good guideline. If you have a 33cm tibia (if you're asian 168cm male, you have similar) 15% of that is 5cm. If you're like 6'3 and african descent, you can probably get away with 7cm tibia lengthening and still be within 15%.

I agree, it becomes an echo chamber in here when you have posters who repeatedly say "NOT 1mm OVER 5CM!!!!!!". 15% makes way more sense as it factors in different body types. The example you gave of the asian vs the african limb lengths made me think of how alot of people could be over lengthening their femurs and going way past 15%.

An individual would want an original femur length of around 53cm if they wanted to safely stick to 15% lengthening. This will be very unpopular to say but I imagine many here are over lengthening their femurs by going to max out at 8cm when they are very short to start with. Much like the big tibia lengthening of the past, RGkey anyone? Those who use "BUT DA NAIL GOES TO 8CM!?!?" to determine their femur amount is unwise in my opinion. Paley was even asked if he wanted the Stryde nail to go longer and he said NO as he knew LLers would take it to the maximum amount. Just because it goes to 8 doesn't mean everyone should especially the very short, this surgery is way too individual.

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ghkid2019

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Re: What's the safe limit for femur lengthening?
« Reply #19 on: September 25, 2020, 05:42:37 AM »

Anyone know what is the average femur length for a 5'7 male? I'm trying to get an estimate of how long my femur bone is, I don't really know how to measure it.

Ideally I want to do 5 cm femur to get to 5'9 sometime in the future. Wondering what % that would be. Mainly concerned with soft tissues

Stopped being concerned about soft tissues and be more concerned with the fact that you're breaking your legs. Your soft tissue is gonna stretch either way, and it will take sometime but new tissue cells will grow. You r worrying about the wrong problem. Ur not fking doing 1.5mm or 2mm. U is doing the normal distraction rate that has been done for 40 fkin years. Just stop it.

And 5cm will be somewhere around 11% to 14% for your height based on my guestimate.
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MakeMeTallAF

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Re: What's the safe limit for femur lengthening?
« Reply #20 on: September 25, 2020, 07:41:28 PM »

Soft tissues are the limiting factor though. That's what the 15% is based on

Bone is not a limiting factor, theoretically you could lengthen 500 centimeters of bone if soft tissues didn't exist

Anyone doing this surgery should be concerned of soft tissues more than anything else. That's where the decrease in athletic ability and long term problems come from.
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F_99

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Re: What's the safe limit for femur lengthening?
« Reply #21 on: September 25, 2020, 07:55:05 PM »

Anyone know what is the average femur length for a 5'7 male? I'm trying to get an estimate of how long my femur bone is, I don't really know how to measure it.

Femur length on average is 26.5-27% of a person's height, so 170cm x (~26.75/100) = ~45.5cm (45-46cm or so).
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ghkid2019

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Re: What's the safe limit for femur lengthening?
« Reply #22 on: September 25, 2020, 11:02:11 PM »

Soft tissues are the limiting factor though. That's what the 15% is based on

Bone is not a limiting factor, theoretically you could lengthen 500 centimeters of bone if soft tissues didn't exist

Anyone doing this surgery should be concerned of soft tissues more than anything else. That's where the decrease in athletic ability and long term problems come from.

Point is, you're   is going stretch. 1mm is ideal to be slow enough to be comfortable while fast enough to not consolidate early.

Trust me you're gonna stop all this BS when you actually do it and just lengthen at doctor's order rate. You ain't gonna gamble your legs to try to game the system. A rebreak osteometry is no joke, and it's extra costs,like 10k for Paley. Stop the bs
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Bane

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Re: What's the safe limit for femur lengthening?
« Reply #23 on: September 29, 2020, 11:18:10 PM »

It looks like 20% is the recommended maximum, because after that the bone regenerate quality declines. But the real limiting factors are the soft tissues, like muscles, nerves, blood vessels, skin, so it's more often recommended around 15%. Lengthening in the 15% to 20% range is feasible as many have already done so, but it requires good health and flexibility, and the determination and commitment of the patient.
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