Poor Jumble, Barty sends his love and woofy licks.
What supplements have you got him on - I have Barty on Cortaflex which does help him greatly. I have to beg to differ about nature ruling out a surgical option for the dear boy. It is possible to get around it and an FHO might give him a better long term quality of life than leaving him on Metcam for life.
Metcam, as I am sure you know, isn't without long term health risks to liver and kidneys and I would urge you to at least ask for a referral to a top hip specialist. If you are anywhere near Nottinghamshire I can thoroughly recommend Barty's old specialist - Graham Oliver.
Anyway more love and hugs sent as I know how hard it is to watch our special "hipless" boys struggle