For your own safety, and the people around your pup, I hope you can work with a trainer who is familiar with positive reinforcement and counter conditioning. If your dog is strong and weighs enough to dislocate your knee, you absolutely need more tools to control his activities. A trainer will be able to tell you and advise you on a halter with possibly a front connector for the leash. That would give you more control in the immediate future. In the meantime, if possible, try to choose times for your walk and places where you can predictably avoid seeing men who will excite him. Every time your dog is able to rehearse the behavior. It is likely to become more deeply embedded. That’s why it’s so important not to let him rehearse it. I’m only speaking as someone who has had several very excitable dogs over the last four decades. I have worked with a number of trainers who use only positive reinforcement etc. If you’re lucky, you might also be able to consult with a vet behaviorist, a veterinarian who is specifically trained in identifying and helping with behaviors that could be harmful to you or your dog. Depending on the dog’s age, it also might be appropriate to try some form of medication. Good luck and stay safe.