My dad had his done one at a time. Dec. , then Mar.
To do both is a bold move.
You obviously want to get out of the hospital asap and they want you out as well.
Now, with that, he is very pleased he did it. The knee pain is gone, except for when his patella (knee cap) snapped last month.
He went in and the end result is that he has 20% of his kneecap left and the tendons, etc. are attached to that. He is still healing in week 2 with a 5-6 week recovery time since they had to open up the same place they just were, though I think it is a parallel incision.
Key is to do all the exercises and rehab.
I suggested that was the opportunity to get back a 1/2 inch or so in height, but nobody listened.

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85' 300D No inspection, No registration fees, Cheap insurance
"If my calculations are correct, when this baby hits 88 miles per hour, you're going to see some serious %$&^."