What is wrong with my puppy?

He's two months old.A lhasa apso bichon mix.So his leg just got like this.It's his front left paw.It's crooked.When he stands it tremble.I felt it.He didn't whine or anything.He seems normal,running and playing.But he can't get uop the steps.Is this a problem.Do lhasa have this problem or the bichon.Please help me! Before my puppy really hurt himself.