"Disappointed "

Was referred to see a specialist after having an x-ray on my right knee I have osteoporosis, osteoarthritis and in chronic pain difficulty walking referral was 4th April heard nothing so messaged them got a message back saying it would be 4 to 6 months for an appointment! Have been referred before 18 months ago for my shoulder and had a shoulder replacement with in weeks and couldn’t praise the surgeon enough what has happened I’m at a loss.