Unfortunately large breed dogs usually end up with bone problems because of their rapid growth and large body parts. A common problem in large breed dogs is Hip Dysplasia that affects their back legs and breeds arthritis. My dog has not gotten Hip Dysplasia yet but he has torn a ligament in one of his back legs.
He had to have surgery done to reattach the ligament and to prevent further development of arthritis in his back legs. Here are some pictures of his surgery..... If you have a soft stomach then I suggest you skip this post.