Agree that the published material is (a) old and (b) thin on the ground. Anecdotally (I have worked with a LOT of hand therapists over the years), its use appears to have a 'softening' effect on the tissues (in my terms this is a change in tissue extensibility). In order to do this, relatively high doses need to be delivered and a significant heat effect needs to be achieved. Whether ultrasound is the optimal way to achieve this heating is certainly not established (certainly not for Dupuytrens) though it would make an interesting and relatively straightforward study. At the end of the day, certainly supported anecdotally if not by recent research evidence.