Old raspberry canes

You could re-plant with runners as long as they're looking healthy. Having said that, perhaps dig them all out and incorporate some fresh soil and compost, grit (if needed) then get some new ones. There is a replacement for Joan J but I can't remember what it is, but someone on here will. 

My raspberry canes did look a bit aged about three years back. I had potted up some 40 runners in black plastic tubs of the size you get small shrubs and things in from the garden centres and which breed in garden  corners over the years using decent compost. Dug out the old canes (and don't anyone tell you that raspberry canes are shallow rooted and don't go far  ) which went for the bonfire. Dug in decent compost and fertiliser before filling up the bed in the autumn. The only cost was labour and some compost.