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[theuprising]

Those who have been around the boards long enough have read the medical journal article stating that for every 1cm lengthened in your femurs with internal nail the axis shifts 1mm with doctors like Dr Birkholtz stating that this can lead to arthritis hence why its best to lengthen smaller amounts.

My question: How does lengthening external femur not also cause this issue?

[ForcedPuberty]

externals lengthens along the mechanical axis.

internals lengthen across the anatomical axis.

the only solution to internals is reverse Planning method FOR INTERNALS, however to do this you HAVE TO GO THROUGH THE KNEE. its called retrograde insertion.

so you have a choice(for internals):
1) lengthen along the anatomical axis and your knees end up closer together,     OR
2) (reverse planning method)which go through the knee and risk permanent knee pain however your knees will not be closer, they will be the same distance as when you started.

[theuprising]

Interesting FP, would this mean that internal femurs would help people with bow legs or am I missing something?

[Taller]

YellowSpike had bow legs before lengthening gis femurs along the anatomical axis. Now he claims that his leg alignment is much better. So, maybe there is merit to your theory, theuprising.

[TRS]

If your mechanical axis goes through the medial portion of the knees, then you will benefit from antegrade nailing and lengthening along the anatomical axis of the femurs. This can actually decrease the risk of arthritis in the future. Your surgeon should be able to determine whether your axis will be corrected by looking at the X-ray and using a simulator.

[theuprising]

If your mechanical axis goes through the medial portion of the knees, then you will benefit from antegrade nailing and lengthening along the anatomical axis of the femurs. This can actually decrease the risk of arthritis in the future. Your surgeon should be able to determine whether your axis will be corrected by looking at the X-ray and using a simulator.

Thanks for the info TRS.
I forgot to ask you, how can a persons tibias still be bowed even if antegrade nailing and lengthening along the anatomical axis of the femur was relevant in their case. If you don't mind my asking are your legs still appearing to be bowed out at the tibia?

[TRS]

I forgot to ask you, how can a persons tibias still be bowed even if antegrade nailing and lengthening along the anatomical axis of the femur was relevant in their case.

Under normal circumstances, lengthening the femurs only should not affect the anatomical position of the tibias. If your tibias are bowed and you lengthen your femurs, then the tibias will still be bowed.

If you don't mind my asking are your legs still appearing to be bowed out at the tibia?

Both of my femurs and tibias were malaligned prior surgery. The PRECICE2 nail only corrected my femur alignment.
However, the PRECICE2 nail did not correct my tibial malalignment and therefore my tibias are still malaligned with 8 degrees varus. My lower legs do look bowed. The solution to this is external tibias, preferably with a hexapod fixator or Taylor's Spatial Frame.

[ForcedPuberty]

don't know the answer for sure, but I don't think it will help bow legs.

[YellowSpike]

YellowSpike had bow legs before lengthening gis femurs along the anatomical axis. Now he claims that his leg alignment is much better. So, maybe there is merit to your theory, theuprising.

Absolutely. Both doctors I consulted with before doing LL noted my bowlegs right away. I had a moderate degree of genu varum (bow legs). After LL, my knees are significantly closer together and appear much more straight. Dr. Guichet told me before the surgery that this would likely happen.

[ForcedPuberty]

did gitchet say it was because of bone remodeling?

[YellowSpike]

did gitchet say it was because of bone remodeling?

No he didn't. He just told me at my initial consultation that I could expect my genu varum deformity to improve somewhat from the femur lengthening (and it definitely did).

[Medium Drink Of Water]

externals lengthens along the mechanical axis.

internals lengthen across the anatomical axis.

the only solution to internals is reverse Planning method FOR INTERNALS, however to do this you HAVE TO GO THROUGH THE KNEE. its called retrograde insertion.

so you have a choice(for internals):
1) lengthen along the anatomical axis and your knees end up closer together,     OR
2) (reverse planning method)which go through the knee and risk permanent knee pain however your knees will not be closer, they will be the same distance as when you started.

How does that work exactly?  Seems to me that the intramedullary canal of the femur is still along the anatomical axis no matter which way you insert the nail.

[ForcedPuberty]

are you asking about the reverse planning method?

[Medium Drink Of Water]

Yes.

[ForcedPuberty]

http://www.ncbi.nlm.nih.gov/pubmed/19685230

the only problem with the reverse planning method, is you have to decide what length you want at the beginning. you can not change your mind half way through.

Postsurgical lengthening will occur along the axis of the straight nail.

basically you pre calculate the future mechanical axis. and then fit the nail accordingly. but yes the nail is straight.

[ForcedPuberty]

its hard to explain.

so bear with me.

the above post answers it but just incase you want a better visualization.

imagine a monorail. ( and imagine the patient is a skeleton with nothing but bones)

now imagine a monorail on a leg sideways. (perpendicular to the leg)

the bone will not gain length(height) but both segments of the bone will separate only along the mechanical axis.
this is the principal.

---------------------

truthfully imagine a slanted device, this will cause a mechanical deviation without a anatomical deviation.

this is the principal for reverse planning method.

[theuprising]

externals lengthens along the mechanical axis.

internals lengthen across the anatomical axis.

Does this mean that if someone lengthens internal tibias that they will cause misalignment as it is along the anatomical axis?

[ForcedPuberty]

Hello All


I want do femur lengtheing but is this a good reason not to do internal femur lengthening ?

The effect on mechanical axis deviation of femoral lengthing with an intramedullary telescopic nail  http://www.ncbi.nlm.nih.gov/pubmed/22933497



Here’s what Rainy said on old forum :

Long after healing from internal femur lengthening, I have cracking joints that get stuch with Knee/hip movement. Although stretching helped muscles some, but ligaments remain short. From what I’m feeling, femurs have shifted from their natural position in the joints and get struch with movement. Femurs are pushed forward on top of tibia in the knees and hurt when trying to bend them. Femur head in hips feel and sound like pop in and out of socket. Of course not completely out, but slightly off.  Enough for major problems in the future.. Premature arthritis… I lengthened within the “safe limit”. I don’t think there is such a thing as guaranteed safe limit for over 1 cm. Any amount of lengthening is very unnatural and hit or miss how much your body can adapt..

[ForcedPuberty]

also I don't know but I suspect this is why greekster cant run. no pain, just cant run. his body wont let him.

[Medium Drink Of Water]

Does this mean that if someone lengthens internal tibias that they will cause misalignment as it is along the anatomical axis?

No.  In tibiae, the mechanical axis and anatomical axis are the same.