Dislocated Kneecap: As we all know, the kneecap is a bone that acts as a protective cover for the knee-joint. It prevents premature wear and tear of the knee-joint. However, when the kneecap is displaced from its normal position, due to trauma, (accident or a sports injury) it can cause chronic pain. A change in direction while running can cause a sudden twist, leading to dislocation of the kneecap.