Quality of life after ACL surgery

My almost 9 year old lab, tore his acl two summer who’s, originally he had metal plates put in due to infection from allergy they were removed and they fused the bone. He’s never been the same, ever since longer walks have often would make his limp or stiff . The last two months he’s been worse, although he’s walking fine I noticed him putting less and less weight on the leg, he’s can’t run for any amount of time without limping after. The vet always warned he would be different after but what does life look for a dog this case? I consulted with our local vet she isn’t to concerned but I have thought of booking an appointment at the vet hospital that performed his surgery. He’s got great health , he will still run but I concern his quality of life may be affected now.