I don’t know about TD but you are describing Duyputren Contracture. It’s when a tendon becomes tethered at the base, drawing a finger in toward the palm. Eventually you can No longer straighten it - meaning you fail the tabletop test and can no longer lie your hand flat on the table. That’s a Medicare Requirement to obtain approval for surgery.
Its related to trigger finger but the latter can be relieved by steroid injections.
I’ve had both in multiple fingers. I’ve had the surgery. And I’m getting ready to have it again in January.