A rotator cuff is made of the tendons of four muscles. It surrounds the head of the humerus like a cuff. One part of these muscle attachments is located below the top of the shoulder. So these parts lie between two opposite, movable bones and are therefore endangered. The tendons keep the head of the humerus within the joint and centre it in the shoulder socket when moved. If the centering of the head is disturbed or if the space is constricted various pain syndromes and shoulder disorders may result from it. Inflammations of the bursa, tendon irritations or premature wear of the tendon can be the result. Sometimes the tendon tears after a fall or strenuous work. However the tendon has to have suffered a prior disorder. A healthy tendon will seldomly tear during an accident. It the tendon is torn it will not grow back together by itself! On the contrary: The tear becomes larger and larger until the tendon is completely disintegrated (an operation with tenosuture is not possible then) and the muscle degenerates (muscle fibres are changed into fat and the muscle itself loses every function). Because of this rupture the shoulder will never function "normally" again without an operation (reconstruction of the tendons), as it will have lost its ability to centre. Some patients learn to still move the arm, using tricks. But the strength in the arm will decrease further. Pains are the direct consequence, especially at night. These can become unbearable. These pains are caused by the remains of the tendon, that can now (like a torn meniscus) become trapped, resulting in a chronic inflammation of the bursa. Caused by the missing tendon the head of the humerus is elevated. Every movement causes a friction of bone against bone which leads very rapidly to an attrition of the real shoulder joint (gleno-humeral joint). We call it a defect-arthropathy. By a defect of the tendon a joint is damaged. An operation at this stage cannot improve or even regain the function of the shoulder. At that stage only a reduction of the pains is possible. Although the following attrition of the shoulder joint can be treated with an endo-prothesis (artificial joint) but as the gearing (tendon) and the engine (muscle) are missing, the result will not be functionally satisfactory. The early diagnosis of the tendon rupture is inexpendable in order to repair the rupture arthroscopically. That means by many small incisions into the skin the torn tendon is sewn back on. That way the advancing joint destruction is stopped and the loss of the arm lifting function as well as the pains are countered.
