Quote from: Purushrottam on June 14, 2018, 11:35:04 PMI think myloginacct posted a study that showed that the risk of arthiritis is higher if the tibia to femur ratio deviates too high from 0.8. That study suggested that bias should be towards lengthening the femur over the tibia.
Yep:
QuoteIncreasing tibia length relative to femur length was found to be a significant predictor of ipsilateral hip and knee arthritis. Therefore, we recommend that when performing limb lengthening, surgical planning should lean toward recreating the normal ratio of 0.80. In circumstances where one bone is to be overlengthened relative to the other, bias should be toward overlengthening the femur. This same principle can be applied to limb-reduction surgery, where in certain circumstances, one may choose to preferentially shorten the tibia.
If you have femur tibia ratio of 0.8, which one is better to be 0.7 or 0.9?
Quote from: myloginacc on June 14, 2018, 11:59:22 PMYeah, probably not perfect measurements. I'm assuming 46cm for femurs and 37cm for tibias.
Still, those measurements give you a 0.804 t/f ratio. That's super normal, at least according to that study. The average deviation is +/- 0.03 from 0.80. Thus, a normal/average T/F ratio, according to the study, is 0.77~0.83.
Going with the quoted "safe figures" in the forums... 5cm on tibias, and 6.5cm on femurs... If you actually did both segments, that'd give you a 0.80 ratio. If you did 5cm+5cm, you'd end up at 0.82. If you did 5cm tibias, 8cm femurs, you'd end up at 0.77. All average according to the study.
On the other hand, if you were lengthening only one segment, you could only lengthen your femurs by... 2cm... to keep within what the study shows as the lower end average for T/F ratio (0.770). For tibias, you could only lengthen them by 1.2cm to keep a normal/average t/f ratio (it'd go up to 0.830). 1.6cm would give you 0.839, the limit at 0.83.
According to this older post: http://www.makemetaller .org/index.php?topic=293.0, it could be up to 52:48. Probably your study just means average range instead of normal range which is difference. For example, a 5'1" man is well below the average height of man of 5'10" but he's not abnormal either because there are many men who are born 5'1". But 4' man is another story.
Quote from: Bruce Wayne on June 15, 2018, 05:20:35 AMAccording to this older post: http://www.makemetaller .org/index.php?topic=293.0, it could be up to 52:48. Probably your study just means average range instead of normal range which is difference. For example, a 5'1" man is well below the average height of man of 5'10" but he's not abnormal either because there are many men who are born 5'1". But 4' man is another story.
Your figures use percentage. 52% femurs and 48% tibias, and 56% femurs and 44% tibias.
Starting from your original (83cm) total leg length:
.56*83 = 46.48
.44*83 = 36.52
36.52/46.48 = 0.78.
.52*83 = 43.16
.48*83 = 39.89
39.89/43.16 = 0.92.
This is the supposed natural range your t/f ratios could have been. Indeed, your femurs are on the longer side of the spectrum according to M M T (0.804, closer to 0.78 - or 56% femurs). Whereas the ratio is almost perfect according to the study.
If you increased your height by 5cm (37cm tibias; 46cm femurs): tibias would give you a 0.91 t/f ratio (supposedly normal given the old forums' ratios). 5cm on femurs would give you a 0.72 t/f ratio (deviating from both the M M T post and the study). This almost seems too good for tibias, and anathema to the anecdotal evidence of femoral vs tibial patients posted here.
I'm not calling bs on the ratios from that post because human proportions vary. Black men have shorter trunks, longer legs (specially tibias) and longer forearms compared to white men of the same height. However, one figure is from a study which examined a cadaveric osteological collection, not written by doctors involved in cosmetic LL (JPO), and which evaluated correlation between t/f and osteoarthritis through multiple regression analysis. The other is by a former admin of the previous forum, a place involved in collusion scandals with CLL doctors, specially getting them to do external tibias in places like India. It may be because I don't have an account on the old forums, but I can't find the source for the ranges he posted and termed as the "normal range" of femur:tibia ratios.
The main counterargument you can use against the study is that it comes from the JPO - the Journal of Pediatric Orthopedics, which is under the umbrella of POSNA - the Pedriatic Orthopedic Society of North America.
However, the Hamann-Todd osteological collection doesn't seem to even focus towards infant and adolescent bone collections:
http://www.oberlinlibstaff.com/omeka_projects/exhibits/show/ohio-bones/the-hamann-todd-osteological-c
https://www.cmnh.org/phys-anthro/collection-database
https://en.wikipedia.org/wiki/Cleveland_Museum_of_Natural_History
QuoteHamann-Todd Human Osteological Collection
This collection contains more than 3,000 cadaver-derived human skeletons collected by Carl A. Hamann and T. Wingate Todd between 1912 and 1938. Superb documentation makes this the world’s largest documented collection of modern human skeletal remains.
The Hamann-Todd Human Osteological Collection is accessible for legitimate research and study by qualified investigators. Access is free for non-commercial use.
Quote from: myloginacc on June 15, 2018, 12:34:01 PMYour figures use percentage. 52% femurs and 48% tibias, and 56% femurs and 44% tibias.
Starting from your original (83cm) total leg length:
.56*83 = 46.48
.44*83 = 36.52
36.52/46.48 = 0.78.
.52*83 = 43.16
.48*83 = 39.89
39.89/43.16 = 0.92.
This is the supposed natural range your t/f ratios could have been. Indeed, your femurs are on the longer side of the spectrum according to M M T (0.804, closer to 0.78 - or 56% femurs). Whereas the ratio is almost perfect according to the study.
If you increased your height by 5cm (37cm tibias; 46cm femurs): tibias would give you a 0.91 t/f ratio (supposedly normal given the old forums' ratios). 5cm on femurs would give you a 0.72 t/f ratio (deviating from both the M M T post and the study). This almost seems too good for tibias, and anathema to the anecdotal evidence of femoral vs tibial patients posted here.
I'm not calling bs on the ratios from that post because human proportions vary. Black men have shorter trunks, longer legs (specially tibias) and longer forearms compared to white men of the same height. However, one figure is from a study which examined a cadaveric osteological collection, not written by doctors involved in cosmetic LL (JPO), and which evaluated correlation between t/f and osteoarthritis through multiple regression analysis. The other is by a former admin of the previous forum, a place involved in collusion scandals with CLL doctors, specially getting them to do external tibias in places like India. It may be because I don't have an account on the old forums, but I can't find the source for the ranges he posted and termed as the "normal range" of femur:tibia ratios.
The main counterargument you can use against the study is that it comes from the JPO - the Journal of Pediatric Orthopedics, which is under the umbrella of POSNA - the Pedriatic Orthopedic Society of North America.
However, the Hamann-Todd osteological collection doesn't seem to even focus towards infant and adolescent bone collections:
http://www.oberlinlibstaff.com/omeka_projects/exhibits/show/ohio-bones/the-hamann-todd-osteological-c
https://www.cmnh.org/phys-anthro/collection-database
https://en.wikipedia.org/wiki/Cleveland_Museum_of_Natural_History
Yeah, I also thought that with 5cm on tibia, I'd still fall into normal range according to the old forum while it wouldn't be the case with femur lengthening. Eventhough, I was wondering how they came up with that number too. But your study actually mentioned the average and not the normal range.
In the end, based on my mockups, I look more normal with the 5cm tibias.
Quote from: Bruce Wayne on June 16, 2018, 05:39:35 PMYeah, I also thought that with 5cm on tibia, I'd still fall into normal range according to the old forum while it wouldn't be the case with femur lengthening. Eventhough, I was wondering how they came up with that number too. But your study actually mentioned the average and not the normal range.
In the end, based on my mockups, I look more normal with the 5cm tibias.
Here's from Paley himself too. Of course standard deviations still exist.
Also, Bruce, if you read this thread again, bear in mind Android said (in his diary) his leg length estimates were totally off. You can only really know your numbers by getting them measured through x-rays.
Quote from: myloginacc on July 05, 2018, 08:52:06 AMHere's from Paley himself too. Of course standard deviations still exist.
Quote from: myloginacc on July 05, 2018, 09:04:08 AMAlso, Bruce, if you read this thread again, bear in mind Android said (in his diary) his leg length estimates were totally off. You can only really know your numbers by getting them measured through x-rays.
Fair enough. My estimation is most likely wrong.
Based on the measurements I took of myself, I seem to have a femur to tibia ratio of 0.92. I always had difficultly running, where my calfs would fatigue quite quickly and I need to walk a bit and recover before I can run or jog again. I am now starting to think maybe it's related to my femur/tibia ratio.
Mine are probably around 50-50 example tibia is 35 cm and femur is is around 35 cm as well
Quote from: Moon knight on August 01, 2018, 04:08:14 PMMine are probably around 50-50 example tibia is 35 cm and femur is is around 35 cm as well
That makes you an excellent candidate for femur lengthening and not just to be taller but for maintaining joint health in the long term. Usually the top range is 0.92, but you're 1, which is unusual. Did you measure yourself or with assistance?
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