Poor Maddie. I wouldn't be opposed to using a cart, but this would be a great question for the specialist first. I'm wondering if the cart would hinder potential progress and improvement that might be gained through regular walking (short walks to start, in grass where she can keep her footing better). 6 weeks is not a very long time. I know with humans that surgery like this can require much longer to show more improvement.
You could also add in stroller rides for the time being. Being outdoors, the sights, sounds, and smells are all stimulating for a dog. Whenever Max has been on restricted activity for various reasons, he has enjoyed stroller rides.
Sending best wishes for Maddie.
__________________ Kristin, Max and Teddy  |