Tendon rupture at the arm joint can cause arm pain. Tendon ruptures are usually caused by chronic or acute injuries and can lead to symptoms such as intense pain, localized swelling, and limited movement. Tendon ruptures cause damage to the tendon tissue, which can cause irritation to the local blood vessels and nerves, resulting in congestion, swelling, and pain. If the affected area is in the arm, it can cause arm pain. The first step after a tendon rupture is to apply brakes and avoid moving the affected area. If the tendon rupture is mild, it can be treated by immobilization in a cast. If the tendon is completely ruptured or mostly ruptured, the ruptured tendon will need to be surgically repaired. It is important to go to the hospital in time after a tendon rupture to avoid affecting the function of the joint.