Osteoarthritis in right knee

Spoke to my doctors surgery today and been referred to the Clinical Assessment and Treatment Services (CATS). They received the referral 7 days ago.

Just wondering how long I should have to wait to hear from them. Had x-ray done which didn't show up anything. But I did have surgery done on it back in 2014 where I had some bone removed some cartalidge removed and cleaned out. Been applying ice packs resting and now taking Tramadol as I can't put that much weight on my leg and it keeps locking up.