Claw injuries and broken claws are relatively common problems in dogs, but can also affect cats and can be painful and uncomfortable for your four-legged friend. A common cause of broken claws in dogs is that the claw has become too long. In some cases, a broken claw can occur without any external force, and this is called a detached claw capsule. The causes of detached claw capsules can be tumors, infections or autoimmune diseases.