Awkward postures and repetitive work have been attributed to shoulder fatigue. Superior and anterior-superior migration of the shoulder is quite concerning as it implies disruption of rotator cuff. If timely treatment is not sought, the condition will aggravate. Characteristics of a rotator cuff tear such as a larger size has been associated with superior and anterior-superior migration of the shoulder.
When a rotator cuff tendon tears, it can allow the ball of the shoulder joint to move upward or outward from the socket. This results in superior and anterior-superior migration of the shoulder. This can lead to loss of shoulder function and sometimes pain. Reduced range of motion of the shoulder is the key symptom that one has to keep in mind in terms of superior and anterior-superior migration of the shoulder. As a result, there will be loss of arm motion and you will find it very difficult to lift the arm up. Ironically, the symptoms of superior and anterior-superior migration of the shoulder mimic other shoulder problems, so getting an accurate diagnosis from a skilled orthopedic surgeon is very important for timely diagnosis and treatment of the condition.
Let’s first understand what migration of the shoulder is.
The shoulder is a ball-and-socket joint. The ball is located at the end of the arm bone (humerus). The socket is an extension of the shoulder blade and is flat in shape. The ball is much larger than the socket, more or less like a big ball on a dinner plate. The ball is held into the socket by a number of things such as muscles, ligaments, labrum, rotator cuff. The ligaments are rope-like structures that go from the socket to the ball. Ligaments keep the ball from rolling out of the socket. However, the rotator cuff muscles originate from the shoulder blade and as they get close to the joints they transform into tendons. These tendons form a cuff of attachment around the front, back and top of the ball. When the muscles contract, a pull force is applied to the tendons, which in turn pulls on the ball, causing it to move. When the arm is rotated, lifted or moved, the ball rotates on the socket. For effortless movement of the arm, the ball has to be in a position which is nearly in the middle of the shoulder socket. In other words, the center of the ball and the center of the socket should stay fairly close. If there is a misalignment between the center of these two structures (the ball and the socket), the ball will not rotate correctly, which in turn will lead to loss of arm movement. When the ball of the shoulder joint is not entirely in the center of the socket of the shoulder joint, it is called migration. In other words, subluxation. The point to be understood is the ball of the shoulder joint does not completely dislocate out of the socket, but the ball is rotating out of the center of the socket enough to cause loss of range of motion. Thus migration happens.
What is superior or anterior-superior migration of the shoulder?
Superior or anterior-superior migration of the shoulder is generally seen in two types of patients. The first are those with relatively large rotator cuff tears where one or multiple tendons are completely missing, whereas in the second category are those who have had unsuccessful shoulder replacement surgery and as a result the rotator cuff tendons get weak.
In normal situation, the ball is kept in the center of the socket by the ligaments and rotator cuff tendons. When the rotator cuff muscles are weak or not present (as a result of a tear), the ball of the humerus no longer sits in the center of the socket. When the humeral head rides upward, it is called superior migration of the shoulder. In some individuals the humeral head may not only migrate upward, it may migrate toward the front of the shoulder as well. In this situation, the ball not only moves upward abnormally in the socket, it also moves too far forward. When the head moves in this direction it is called anterior-superior migration.
Signs and symptoms of a superior and anterior-superior migration of the shoulder:
The principal sign of this condition is the arm losing its motion. When a person with this condition tries to raise his/her arm, they can only raise it about one third of the way up or around 60 to 70 degrees. There will be a prominence in the front of the shoulder as ball goes up and forward. The loss of full range of motion of the arm above shoulder level makes it difficult to reach into overhead bins or to the back of the head.
The second predominant symptom of this condition is pain. In fact, not everyone with this condition feels pain. However, when pain is present, it can be located in the shoulder area, arm or in the middle of the arm. The degree of pain is related to the extent to which one tries to use his/her arm. Pain is generally present when one tries to lift heavy objects or lift over shoulder height.
Diagnosis of the condition:
The condition is diagnosed based on your past medical history, physical examination and radiographs. History of an injury to rotator cuff can act as a clue to zero in on the condition.
Treatment for superior and anterior-superior migration of the shoulder:
The treatment for the condition based on the symptoms of the patient; whether the problem is loss of flexibility or pain, or both. The treatment is tailor-made for each patient based on the complaints. One strategy is to avoid the activities that trigger the symptoms, particularly heavy lifting or trying to carry heavy objects away from the body. Another method is to treat the pain with ice or heat; whichever ameliorates the pain. Ice packs are more suited if the shoulder is sore.
It is very important to avoid the shoulder getting stiff. Stiffness further deteriorates the range of motion of the shoulder and aggravates the pain. On that count, physiotherapy can be helpful to help range of motion and strength. However, correction via operated route is indicated when the conservative measures fails to bring the desired result. The nature of the surgery depends on the problem experienced by the patient.
It is necessary to have a consultation in the first place with an expert before embarking on any forms of treatment.
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