You 'could' use some proprietary bagged compost at the bottom of the hole when you plant the seeds but, if you've been growing successfully for several years without I probably wouldn't.

Runner beans are one of the few veg that are happy in the same spot from year to year. Many old gardeners used to dig a deep trench and throw in all the stuff that would go in a compost heap, including old newspaper (though modern printing inks might make that a bad idea).Otherwise you can manure in autumn If you look at allotments you'll see that the bean racks are not moved. Beans fix their own nitrogen but if you want to feed use a bit of sulphate of potash a couple of weeks before sowing.