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The natural history consists of bowed legs, knock knees, bow legs, knock knee consists of spontaneous resolution. The varus is worst at birth, neutral at 18 months and valgus at 30 and 36 months. That is what happens. This is by a group out of Sweden who documented a lot of kids with bowing and knock knees and this is the natural history. So you can put these up in your office and the kid comes in and has this much bowing at 1 year or 2 years and you know that it falls within a certain amount of standard deviations of normal. The alignment is usually adult by 4 to 5 years and x-rays of this are bowed legs.
Reassurance is the key unless there are severe bowed legs or knock knees at 18 to 24 months which they should have already resolved. That you want to think about Blount’s disease and rickets which are treatable and are severe if they are left alone. If a patient has significant short stature like metaphyseal chondrodysplasia and bowed legs, that is abnormal. If they have asymmetrical involvement, one leg really bows and one leg doesn’t, then you want to think about these things like focal fibrocartilaginous dysplasia. Or if it is an adolescent, adolescent Blount’s disease. Or if they have a positive history for dwarfism and that is something.
Here is a kid that comes in, sent in with bowed legs. He’s got bowed legs here you could drive a train through. But the kid was under the age of 2 years so they watched it and this is what happens over time. That’s almost always what happens over time.
This is a kid with some serious bowed legs and this is a kid with some less serious bowed legs. These bows look like big "C"s. They are really round, like making an O. This kid has a fairly straight femur right here. His bowing takes off right here is where he starts to bow. In other words, it is almost like he has two straight segments connected by a joint here but the joint is going the wrong way. It is going mediolateral. This kid has Blount’s disease. This kid has regular good old physiologic bowing.
This is the x-ray of the little black kid who was 18-month-olds. He has really no involvement of his proximal tibial metaphysis. It looks pretty normal. This kid has this really severe beaking – this growth arrest here in his tibial metaphysis proximally. That is a sign of Blount’s disease and