heavy mulch

Ditto what bambooo said. If you can still work in the beds, mulch with pretty much anything organic you can get. The weeds might not kill the perennials you want to keep but there's an old saying, "one years seeds equal seven years weeds." The weeds will produce millions of seeds and give you fits over the next few years. Plus, a well mulched bed will be less likely to suffer from any drought you get this summer.

The herbicides for lawns kill broad leaf plants and most perennials fall into that category. There is at least one herbicide that kills grass but not broad leaf plants. If you use that, be sure to read the label carefully since it's not safe on all ornamental perennials either.

Good luck with your surgery. Maybe you could supervise somebody else doing the weeding this summer. It would be a good learning experience for some young person in your neighborhood or some young family member with a stronger back and hips. Use a stick to point to the "weeds" as opposed to the desirable plants. Lessons in horticulture and experience in caring for others are invaluable.