Hello,
Not sure if this has just come on or if you have only just noticed it but I have a sow who was sat on by her mama at birth and has a deformed leg. We call her 'big leg'!
Big leg has a very oddly shaped foot, very low on her pastern with one toe pointing upwards and the little side bit curled up. She has always been a bit strange in her gate because of it but has never gone truly lame. If she had we wouldn't have kept her for breeding but she has managed a winter litter last year and looks no worse for it.
Obviously if you can't trace the cause of the problem, it has come on suddenly or she is in pain, you need to be getting a vets opinion.