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Common Conditions of the Shoulder
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GENERAL INFORMATION
The shoulder is classified as a ball and socket joint. It is the most mobile joint in the body as well as one of the most complex. Three bones come together at the shoulder: the humerus (arm bone), the scapula (shoulder blade), and the clavicle (collar bone). The head of the humerus rests in a shallow socket in the shoulder blade called the glenoid. Because this socket is usually much smaller than the humeral head, a soft fibrous tissue rim, called the glenoid labrum, surrounds the socket to help stabilize the joint. The rim deepens the socket by up to fifty percent so that the head of the humerus fits better. Altogether there are eight ligaments that hold the shoulder together and fifteen muscles that act on the shoulder joint.
Shoulder injuries can be caused by sports activities like swimming, tennis, pitching, weightlifting, or everyday activities like gardening, washing walls, or painting. All these activities require a repetitive overhead movement. It is not unusual for some people to underestimate the extent of a shoulder injury because steady pain, weakness in the arm, or limitation of joint motion can become almost second nature. Most problems with the shoulder involve the muscles, ligaments, and tendons rather than the bones. Some of these problems are explained below.
IMPINGMENT SYNDROME
Impingement syndrome involves one or a combination of problems, including: - Bursitis: inflammation of the lubrication sac (bursa) located just over the rotator cuff - Tendonitis: inflammation of the rotator cuff tendons - Calcium Deposits: deposits of calcium within the tendons caused by wear and tear injury - Bone Spurs: extra bone under the acromion, a bony-tipped part of the scapula, that can press on structures surrounding the shoulder joint
The above problems alone or in combination effectively decrease the space within your shoulder joint, causing a pinching pain when the shoulder is used. In some cases, you may even feel a nagging pain when you are not using your shoulder, such as at night. If you do not seek medial care for inflammation in your shoulder, it could eventually lead to a more serious injury involving the rotator cuff or biceps tendon (see below).
If detected early, impingement syndrome may be treated with physical therapy, cortisone injection and/ or anti-inflammatory medication. All of these methods aim to keep the shoulder mobile while decreasing the inflammation in the area and creating more space in the joint. If these conservative methods fail, surgical decompression may be indicated. This surgery is a same day procedure and involves taking off any excess bone under the acromion and excising a thick, unnecessary ligament which decrease space in the joint, as well as evaluating the rotator cuff and/ or biceps tendons to make sure they are not torn (see rotator cuff tears below). A sling is worn after surgery and physical therapy is used for several weeks post-operatively to help you gain back the motion and strength in your shoulder in a gradual, monitored fashion.
ROTATOR CUFF TEARS
The rotator cuff is one of the most important components of the shoulder. It is comprised of four muscles and their tendons that surround the top of the humerus and hold it in the shoulder joint. The rotator cuff muscles and tendons provide you with the ability to move your arm, lifting and reaching overhead and turning it inward and outward.
When the cuff has a tear, the muscles cannot function properly in helping you to use your arm. Often, this is felt as weakness when the arm is lifted above the shoulder, as with lifting objects overhead. Grating, weakness, or catching may also be felt in this position. As with impingement syndrome, the shoulder may also be tender over the acromion, the prominent tip in the shoulder, and pain may be noticed when the shoulder is not being used, such as at night with difficulty laying on the affected side.
A rotator cuff tear is often suspected during the history and physical examination. If a rotator cuff tear is suspected, x-ray and/ or MRI pictures might be taken of the shoulder to confirm the diagnosis. Partial thickness tears may respond well to conservative treatments such as physical therapy, cortisone injection, and/ or anti-inflammatory medication. If partial thickness tears do not respond to these conservative treatments, surgery may be recommended. Full thickness tears do not repair themselves, thus requiring surgery to correct. If you have a full thickness tear, your physician will discuss with you if surgery would be appropriate according to your functional needs.
Rotator cuff surgery involves decompression of the shoulder (see above “impingement”) and repair of the cuff by suturing the tendons of the cuff back together. A shoulder immobilizer, similar to a sling but slightly more restrictive, is worn after rotator cuff surgery, and physical therapy is used post-operatively to help you regain your motion and strength on a gradual, monitored basis while the cuff heals. It is important to note that occasionally the rotator cuff is irreparable, either because the tendons are too retracted back to be able to pull them back together, or, because the tissue is too weak to be held together by artificial materials such as sutures.
The biceps muscle forms two tendons that each separately attach the muscle into the shoulder. The long head tendon, inserts in a groove in the head of the humerus and can be felt when your arm is rotated inward and outward from the body. The short head tendon inserts in a bony process of your shoulder blade, located in front of your underarm area.
Ruptures most often occur during a trivial event as a result of long-standing biceps tendonitis or impingement syndrome condition, though a previously unworn biceps tendon can tear during very strenuous activities. Ruptures in the biceps can occur in the shoulder area ("proximal", most common), in the elbow area ("distal"), or within the length of the muscle itself.
Biceps tendonitis produces nagging shoulder pain and tenderness in the groove. Biceps dislocation produces similar symptoms, but the tendon can be felt to slip out of place. A rupture is often heard by a snap followed by mild pain initially. Ruptures usually produce bulges in the arm where the tendon has separated and the muscle has slipped down into the arm. Here, bruising can be seen tracking in the middle part of the arm. If a rupture occurs at the elbow area (rare), pain and bruising is often felt more towards the elbow rather than the shoulder, though the bulge may be noticed in a similar position as the muscle is pulled upwards towards the middle arm.
Diagnosis of a biceps problem involves a careful history and physical examination. X-rays and an MRI are common diagnostic tests involved in confirming the diagnosis while excluding other problems such as fracture, impingement, tendonitis, or rotator cuff tear.
Treatment of a biceps tendon problem depends on the severity of the functional impairment. The main areas of function in concern are the ability to bend the elbow and to turn the forearm outwards, as with using a screwdriver. Biceps tendonitis and dislocation can be treated without surgery, utilizing physical therapy to maintain motion and strength. Ruptures in the proximal shoulder area can also be treated conservatively to achieve almost full function, although young, active patients, or those involved in heavy labor or lifting activities are more frequently recommended to have their ruptures repaired surgically. Ruptures in the distal elbow area usually require surgical repair in a timely manor, as its attachment to the elbow is critical for any function.
INSTABILITY
While the shoulder has a great range of motion, it can lose its stability and the head of the humerus (the “ball” in the socket) can sometimes move out of the socket of the joint. It can move either partially out of the glenoid socket (called subluxation), or completely (called dislocation). When the head of the humerus slips out of the glenoid, usually it happens out the front of the joint (called anterior dislocation or instability). Anterior instability can be a problem when the arm is in position for such movements as throwing. Multidirectional instability is often a sign of long standing problems with instability in the shoulder. Rarely, the head of the humerus can be pushed backwards (posteriorly) out of the glenoid, which usually only occurs during awkward movements such as those experienced during seizures or electrocutions when the arms turn inward and stiffen.
Instability is often described as the feeling of the shoulder slipping out of the joint in various positions. If the instability is in one direction, such as anterior, the shoulder might feel unstable when in the throwing position. If the instability is multidirectional, you might be able to correlate certain activities that precipitate the unstable feeling or you might be able to voluntarily dislocate the shoulder.
Diagnosis of instability involves a careful history and physical examination. Your physician might move your shoulder in a variety of positions to determine which direction your instability is prominent, including asking if you can voluntarily dislocate your shoulder or if it happens with ease while lifting your arm overhead. General laxity in other joints of the upper extremity might be examined. X-rays are an important test to visualize how the bones of the shoulder sit in relation to one another, but a variety of views may have to be attempted if your injury is acute and painful. An MRI or arthrogram can help confirm if other problems exist in your shoulder, such as a rotator cuff tear.
Treatment of shoulder instability often depends on whether or not the instability is the result of a traumatic injury and/ or if you have experienced a similar occurrence in the past. Initially, treatment of an unstable shoulder involves getting the shoulder back in to place, a non-surgical procedure called a shoulder reduction. The shoulder is then usually immobilized with a sling. Physical therapy to strengthen the muscles around the shoulder is an important way to prevent further dislocations and instability. If reduction cannot be achieved, therapy does not work, and/ or chronic dislocations occur, surgery to tighten the capsule around the shoulder might be recommended. In addition, traumatic events that cause subluxation or dislocation often cause tears in the glenoid labrum and might also require surgery to remove the torn cartilage (see glenoid labrum tear, below).
GLENOID LABRUM TEARS
Injuries to the tissue rim surrounding the shoulder socket can occur from acute trauma, such as from falling on an outstretched arm or from using the shoulder in a repetitive motion. The glenoid can be torn in different parts causing different kinds of tears. A SLAP lesion is a tear of the rim above the middle of the socket that may also involve the biceps tendon. A Bankart lesion is a detachment or tear of the glenoid rim below the middle of the glenoid socket that also involves the inferior gleno-humeral ligament. Below is a diagram of these two different tears.
The symptoms of a tear in the shoulder socket rim are very similar to other shoulder injuries, including pain with daily and/ or overhead activities, a feeling of instability in the shoulder, and/ or pain in the shoulder at night time. These symptoms may relate to a specific incident, as is common with concurrent dislocation, or they might be symptoms that gradually increase over time. Because these symptoms overlap other common conditions in the shoulder (such as impingement), diagnosis of a glenoid labrum problem is often difficult.
Diagnosis of glenoid labrum tears begins with a careful history and physical examination. Your physician will test your range of motion, stability, and pain patterns to help determine where the problem is located. Frequently, other diagnostic tests are ordered such as an x-ray and MRI or CT scan to rule out other conditions as well as confirm a glenoid problem.
The glenoid labrum is a cartilage in your shoulder socket and will not repair itself. However, whether or not surgery is indicated depends on the degree of your pain and functional impairment. If surgery is indicated, it is a same day procedure that involves arthroscopy to enter the shoulder and excise the torn cartilage. Occasionally, the joint may have to be opened to effectively achieve excision and/ or to correct other concurrent shoulder problems. A sling is worn post-operatively and the physical therapy is used to regain the motion and strength in your shoulder in a gradual, monitored fashion.
ARTHRITIS
Click here fore more information on the general process, diagnosis, and treatment of arthritis conditions.
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