If he is walking on joints , knuckled over, do some stretches with him, a bit of lambie physio, sometimes they can come out with either tendons too tight or tendons too loose, but can improve. Gently bring the leg back and fro, like he or she is doing pointy toes, not over stretching. Can also splint, making sure that nothing is too tight. Using soft gauze, cotton wool, and lolly sticks or similar x