We discovered that when Annie drags her back leg, it falls to the side. When she attempts to go forward in this cart, she runs over her back leg - which is why she cannot use it correctly. There is no attachment to hold her leg out of the way - so I returned it to the E-bay seller. They refunded my money, minus the shipping cost. I am pleased with the transaction. We are going to have a company called Eddie's Wheels make her a chair. They have many options as each chair is made specifically for each dog. Annie needs either a device to hold her leg out of the way, or have the wheels splayed out and wider so she will not run over her own foot.
Here is a picture of one of Eddie's Wheelchairs where the dogs bad leg is in a holder. I will keep you informed.
The web site is: