Joint pain is a common problem affecting older dogs, as well as younger dogs that are inactive, too active or overweight. This condition often starts as a small tear in the dogs cruciate ligament (dog acl), which may go undetected and lead to more serious conditions like full rupture of the cruciate, dog arthritis and cartilage (meniscus) injury. Early detection through regular checkups and prompt intervention by a veterinarian are essential in stopping the progression of this condition.