Issues like these are usually caused by different growth times of leg bones that are ordinarily supposed to grow simultaneously. The cause of that can be quite a few – there are various growth disorders, cancers, pathologic conditions, simple traumas and injuries during the growing phase, or even something as simple as some vitamin and mineral deficiencies.
This is why it’s important to always feed your pups with high-quality food and to be careful when you exercise them. At the same time, even if you do everything right, there is a small chance that an undetected growth disorder will be in effect anyway. So, always be on the lookout for the early symptoms and stages of angular limb deformity either way.