The 20% Rule

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Hey all, many doctors say they only do up to 5, 6, 7.5 so on cms. However, some other respectable doctors say that they recommend lengthening a maximum of 20% of a bones length and 15% would be the safest.

So I decided to see for myself. I measured my tibia from the front beginning at the ankle to the top of the bone before the soft tissue: a length of 3 iPhone 4s or approximately  34.3cm.
20% = ~6.9cm
15% = ~5.15cm

It seems like the safest amount for me is the safe amount that most doctors prescribe (assuming my iPhone measurements are correct).

So would you trust the 20% or 15% rule more than the 5cm like most doctors say?

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Best I've read I what Dr Lee said regarding this issue but I think but I think if you care about athletic ability 15% then 20% if its less important.

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I think percents and ratios are better than absolutes.  Dr. Xia said I could lengthen my tibias until they became equal to my femurs in length, but that I shouldn't go over that.

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Quote from: Medium Drink Of Water on November 29, 2015, 10:04:31 PMI think percents and ratios are better than absolutes.  Dr. Xia said I could lengthen my tibias until they became equal to my femurs in length, but that I shouldn't go over that.

Did Dr Xia give reasons behind his theory? As femur is always the longest bone in the human body and you'd assume biomechanically there is a good reason for this otherwise doctors wouldn't be aware of the 0.80 tibia to femur ratio.

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I didn't ask him to explain the theory behind it, sorry.  I was so desperate to get LL and worried about getting turned away again that I didn't ask anything other than what's the maximum I could lengthen and how soon could I be on the operating table.  He actually volunteered the ratio information.

It's probably that there's an acceptable range that the ratio could be if you're getting LL on one segment.  From 1 to 0.6 or something like that.

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There is no set number, However some of the doctor's suggest to not go above 15% of existing bone length. Ironically this also means the shorter you are the less you should lengthen to stay with in safe limit.