Wisteria are really super tough plants. Can you pop the plant out of the pot check the roots. Hopefully the roots did not freeze depending on the winter climate and where stored during winter. If roots are white the plant is alive. Wait a few weeks for newer growth to show. In the mean time trim back long stems back to 5 or six buds to encourage blooms. Do not fertilize. Keep watered with good drainage or better yet plant it ASAP. It will do much better in well draining soil give the roots more area to grow for next seasons blooms.
Post a pic in two weeks... would be wonderful to see the progress.
Below pics taken 5-3-20. This plant is a double Japanese wisteria 30 years old. Trim in summer and always trim back to 3-4 buds every fall for next seasons blooms.
There is a nice tutorial on how to prune wisterias for them to flower every season. https://youtu.be/85dOUnLjCSI