Dear Ashok:

Non-unions are routinely classified into two groups either hypertrophic or atrophic according to their radiological appearance.

Hypertrophic nonunions

◦ Exuberant callus formation

◦ Because of their vascularity, they have excellent healing potential

◦ Result from inadequate immobilization of the fracture

Atrophic (oligotrophic) nonunions

◦ Absence of callus and bone ends that may be tapered and osteopenic or sclerotic

◦ Because of their lack of vascularity, they have poor healing potential

◦ A subcategory of this type may be freely movable and form a pseudarthrosis

Dear Nelson,

Thank You for your answer.

My main confusion in differntiating Atrophic from Hypertrophic Nonunion is particularly Between Oligotrophic and Atrophic Nonunion. But you have mentioned above that Atrophic is Oligotrophic. According to Campbell, Oligotrophic Nonunion is a type of Hypertrophic Nonunion. It says it is not hpertrophic with callus formation but it still is Vascular.

So, what are the diffentiating radiological features of Hypertrophic, particularly Oligotrophic and Atrophic Nonunion ??

WIth Regards.

Dear Ashok

The radiological differentiation between oligotrophic and atrophic non union is difficult but in the atrophic nonunion a gap is often present and this does not occur in oligotrophic. Best regards

Dear Nelson,

Thank You.

If I may simplify the hypertrophic nonunion is X-ray presented usualy with shape of the "elephant´s foot" while the atrophic one presents the shape of two "icicles" as my teacher Prof. Cech explained in his monography..

Dear Zidka,

I understand that 'Elephant foot" type and even "Horse roof" type can be identified. But I was just wondering to know about the differentiating features of "Oligotrophic" type and Atrophic Nonunion.

Atrophic Nonunion resembling the shape of two "icicles" is interesting though !!

Thank You for your reply.

With regards.

Oligotrophic means that some vascularity exists /from Greek oligos means little/ while atrophic means that no vascularity exists. So one should assume that in oligotrophic non-unions some signs of callus formation are to be noticed on x-rays'but not sufficient to bridge the gap. Exuberant callus is typical for hypertrophic non-unions.

hi Ashok. please look for RUST score. in atrophic nonunion it would b 0 but in oligotrophic RG score would b there but less than 7 or 8.

RUST score is a good means for grading non-union, although it is hard to juxtapose its validity on other scoring scales.

Dear Ajai Singh,

Thank you very much.

Dear Panayot Tanchev,

Thank you very much.

Dear Ajai and Panayot,

Would you please send me an article (PDF) reagarding RUST score.

Its completely new to me.

Thank you very much.

Regards.

Dear Ashok, RUST score is proposed previously to grade and assess tibia fracture non-union. Later it is successfully applied for other fractures. For example - hip fractures. See below www.biomedcentral.com/1471-2474/14/70

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Dear Panayot,

Thank You.

Regards.

The most common teaching is that atrophic non-union implies no evidence of callus formation at the fracture site. hypertrophic non-union implies that there is excessive formation of callus on plain x-rays. Elephant or horse-shoe foot hypertrophic non-unions are variations of excessive callus formation.

Dear Nkosana,

Thank You.

Regards!!!