Missing senior cat

Our ~11 year old cat has not come home in days, the last time he didn't come home was because he was seriously injured and couldn't physically make the journey so we're very worried. We live in Cnocan Glas, which is upper Westside, he is a larger tabby male cat, he does not have a collar, he has an odd walk very stiff and slow with shoulders wide apart. He is completely indifferent to humans will not respond to his name being called or anything but he does fight cats.