I guess plug grafts would be subject to donutting at several stages in the maturation process. Initially if the center of the graft was not able to establish circulation, it would donut rather quickly. I would say in the first couple of weeks.
Then there is also danger in the later stages of healing where scarring causes the punch graft to contract. The contraction could strangle any circulation that was initially established, creating the hypoxia, as you had stated. This could happen anytime in the first year as changes to the tissue mature and settle.
Foote does have an interesting point. However, I don’t agree that the edema-DHT-lymphatic pressure idea would cause the donutting. But rather that the contraction of the graft can complicate the normal life cycle morphology of the hair. This might then lead to the inflammatory response that Foote is talking about.
During the anagen or growing phase of the hair, the root of the follicle extends down to the subcutaneous tissues. The cells of the follicle are hypertrophic and active. This phase lasts about 7 years on the scalp. But when the hair goes into telogen or resting phase, the entire follicle crenates and shrinks up towards the surface of the scalp. Contraction of the graft due to scarring could interfere as the telogen hair begins into the anagen phase again. There might not be room for the follicle to expand into it’s active form again. This phenomenon would be seen at around 6 or 7 years.
It is possible that this could cause inflammatory edema secondary to the follicle being compressed. There has been research that shows higher concentration of DHT in areas of inflammation on the scalp. The lymphatic pumps would be active due to the inflammatory response to deliver extra white blood cells.
Foote might be on the right track, but it seems a bit backwards in the mechanism flow. The answer is that Foote should have talked to Dr. Cole’s assistant Jessica before publishing his hydraulic theory to get the details right. Hahaha! Just kidding! I’m just speculating as to what I think might be happening.
I’m pretty sure that we don’t know enough about the cellular mechanisms within the follicle to know this kind of stuff for sure. But perhaps this could initiate some research. Could some one get a grant and find out for us?