What does Sesamoid Avascular Necrosis (osteonecrosis) Look Like?

Bone Fragmentation is Noted in AVN (here of the lateral or fibular sesamoid

This view showed the tremendous inflammation between sesamoid and metatarsal (this is actually why the patient hurts)

Another view of the fragmentation on CT Scan (these pieces will never come together)

The view is T1 (meaning healthy bone should be white) of the bottom of the foot

This view is T2 (normal bones can look like this) but the T1 and T2 should be different. You can tell the lateral sesamoid is both darker than the medial sesamoid and the white within is just the inflammation seen between the fragments.

So, it you just looked at T2 here, you would be misled as the sesamoid are darker, and there is tremendous inflammation within the joint.

This is crucial to making the diagnosis of AVN with the lateral sesamoid dark on the T2 above and T1 here. A fractured sesamoid can be dark on T1, but should be very bright with inflammation noting healing potential on T2. 

I discussed with the patient, who has had 2 years of pain, that AVN has occurred and removal of the lateral sesamoid is recommended. However, if he wants to try one more year of conservative treatment, even when the fragments will remain separate (some of these just do not hurt), then daily Exogen bone stimulation, contrast bathing twice daily, and some regimen of acupuncture, could be tried.