Most limb injuries (i.e. to the arms, including the shoulder/elbow/wrist joints, and to the legs, including the hip/knee/ankle joints) come from improper use of the limbs. Specifically, from carrying excess tension in the limbs and using them as the primary source of strength and leverage. This creates rigidity, weakness, and fragility over time.
The limbs are just extensions of the body (trunk) and should be used that way. But since modern living has most people moving in such limited ways, people become like robots - disconnected from their bodies and unable to use the body in its natural integrated capacity.
Learning to move better, more naturally, through a regular movement practice and/or proper training can eliminate a lot of unnecessary problems and correct existing ones.