No need for any extra supplements if you are in good shape. Walking is a very good natural exercise, doing it everyday will naturally increase your bone density and cartilage health. Just be sure you have a balanced diet that contains good nutrients and vitamins and then you're good to go! 

Glucosamine doesn't really work, to be honest, at least for me and for most experts. I once took glucosamine when I was recovering from my knee injury and it wasn't very effective... I had stopped eating it and my knee improved just by eating the right food and doing light physical exercises such as walking and cycling. Oh... my knee was so bad that I couldn't even walk.