Shoulder injuries
From Medical-Wiki
The shoulder is the most remarkable joint in the human body. Its range of motion and utilitarian versatility are a remarkable piece of biologic adaptation. Unfortunately, this also places the shoulder at a greater risk of injury than any other joint.
When considering the array of possible injuries, clavicle fractures are perhaps the most common bony injury with humeral head fractures a close second, particularly in the elderly. The most common soft tissue injuries are shoulder dislocations, rotator cuff tears, and acromioclavicular (AC) sprains.
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Shoulder anatomy
The shoulder joint is comprised of the proximal humerus, the clavicle and the scapula. These are affixed to each other, to the sternum and to the rib cage via the scapula. The configuration of the joint allows the upper extremity to rotate up to 180 degrees in three different planes. [1]
Clavicle fractures
Clavicle fractures are usually easy to notice because of the clavicle’s subcutaneous position. The bone is relatively slender and acts as a strut between the torso and the upper limb. It is attached to the sternum at the sternoclavicular (SC) joint. It is attached to the acromion of the scapula at the acromioclavicular (AC) joint. The clavicle is joined at these joints, and to the coracoid process, via very strong ligaments. The bone is at its weakest at the junction of its middle and distal thirds—making this junction the most common site of fracture. Running behind the clavicle is a neurovascular bundle. Damage to these structures is a factor that must be considered when treating injuries.
Fractures of the clavicle may be caused by direct or indirect trauma. Indirect trauma causes the greatest number of fractures. Typically, a patient will fall onto the lateral shoulder. The force from the fall is transmitted across the clavicle, causing the fracture. Direct trauma can come from a blow or a fall that impinges on the body of the clavicle. Football, hockey, wrestling, soccer, roller skating, skiing, bicycling, or horseback riding are all associated with clavicular injuries. [2]
Humerus fractures
In elderly patients, proximal humerus fractures typically result from falling onto an outstretched arm. Young adults will more commonly incur fractures as a direct blow. The first step in evaluating proximal humerus fractures is checking for the extremity’s neuro-vascular integrity. Because these fractures may be treated conservatively, referral is often not necessary, but this means that the neuro-vascular integrity should be carefully documented. Axillary artery and nerve, brachial plexus, and peripheral nerve injuries can sometimes be subtle. The arm should also be closely inspected for dislocation of the humeral head. This may appear as a bulge — either anteriorly or posteriorly. However, the swelling and pain in the area of the fracture often obscure this finding.
A standard shoulder series of x-rays should include anteroposterior, trans-scapular, and axillary views. Do not allow a technician to shorten this series with only internal and external rotation views of the humerus.
Fractures are classified by the displacement and degree of angulation. More than 80 percent of proximal humerus fractures are nondisplaced and can be treated conservatively. Treatment includes a sling for comfort and early range-of-motion exercises. These are crucial to prevent the frozen shoulder syndrome. They may be initiated as soon as they are tolerated. Patients bend at the waist, dangle the affected arm, rotate it in a circle, and then increase the excursion of the arm over time.
Open fractures, fractures with neurologic or vascular deficits, displaced fractures, fracture-dislocations, and fractures of the anatomic neck require orthopedic referral.
Joint injuries
One of the most commonly dislocated joints is the glenohumeral joint. Of these, roughly ninety percent are anterior. Posterior are the next most common, and inferior are the rarest. Inferior are also quite often accompanied by neurovascular injury as well as fracture. As with proximal humerus fractures, the elderly usually dislocate shoulders during a fall and the young dislocate them through direct trauma or athletic injuries.
Patients with shoulder dislocations will usually present with the arm cradled by the other arm. A bulge where the humeral head rests and emptiness beneath the acromion suggests an anterior dislocation. The arm should be checked for neuro-vascular injuries. A full shoulder series should be ordered. [3]
Reducing shoulder dislocation
One of the difficulties with reduction of a dislocation is the ensuing muscle spasm. The earlier the reduction, the less the spasm, and some clinicians prefer a reduction in the field, even before radiographs. There are a number of reduction techniques that may be utilized.
on how to reduce dislocated shoulder.
Treatment after reduction usually consists of immobilization of the shoulder for four weeks and then rehabilitation. However, it is well established that in a younger population, early surgical intervention provides a better outcome, particularly in athletes. Thus referral of young athletes to an orthopod is a judicious decision.
Soft tissue injuries
Soft tissue injuries to the AC joint (sprains, separations) are exceedingly common. The most common event causing these injuries involves a direct blow to the acromion while the humerus in an adducted position. The resultant forces push the acromion medially and inferiorly. Another common injury is via indirect trauma through a fall onto an outstretched arm or elbow.
The ligaments involved are the acromioclavicular, coracoclavicular, and deltotrapezial fascia. In addition to sprains, the ligaments can be disrupted, detached, or separated. Of these, the first to be damaged is the AC ligament. Then, if enough force is applied, the coracoclavicular ligaments will be torn, and finally, the deltotrapezial fascia injured or detached.
If all support is disrupted or detached, the distal clavicle is freed to rise superiorly. When this happens, there may be an associated fracture of the coracoid process or the lateral one third of the clavicle. This is a circumstance that needs immediate orthopedic evaluation.
When a patient with an AC injury presents, there should first be an assessment neurovascular status. Then, the patient should be assessed for appropriate radiographs. The contralateral side should also be imaged for comparison. While old standards utilized weighted radiographs, their use is now being questioned.
A patient with a type I injury will present with tenderness over the AC joint, no visible deformity of the distal clavicle, and a positive cross-arm test—sharp pain at the AC joint if the patient holds the arm out straight and brings it across the chest.
With type II injuries, the distal clavicle may be slightly more prominent on inspection. The patient will also have pain at the distal end of the clavicle. This pain is from the sprained coracoclavicular ligament. X-rays in this case may be normal but may also show slight widening of the AC joint.
Treatment of type I and II injuries consists of symptomatic relief with use of a sling for one to three weeks, ice, and nonsteroidal anti-inflammatory drugs (NSAIDs). Range-of-motion and general strengthening exercises should begin when pain allows. Usually, patients return to their prior activities although there may be mild complaints of clicking and pain with push-ups.
A patient who presents with an obvious prominence of the distal clavicle and has an x-ray that shows an obvious separation of the AC joint and an increase of the coracoclavicular distance of 25 to 100 percent compared with the normal side has a type III injury.
Types IV to VI have grossly abnormal radiographs.
Type IV, V and VI require immediate referral and usually require surgical repair. The treatment of type III injuries is variable, but it is judicious to refer them for orthopedic evaluation. [4]
Rotator cuff injuries
As America’s population ages and as the portion of that population who participated in long term, vigorous exercise increases, rotator cuff injuries, both acute and chronic, have become an increasingly common problem.
The tendons of the rotator cuff are the main stabilizers of the shoulder. The cuff consists of tendons from 4 muscles, the subscapularis, the supraspinatus, the infraspinatus, and the teres minor.
When evaluating a shoulder for a rotator cuff tear, there are three clinical findings that have proven to be useful: supra-spinatus weakness, weakness of external rotation, and impingement. When all 3 tests are positive, or when 2 tests are positive for a patient older than 60, there is a 98% chance of the patient having a rotator cuff tear. Physical exam will often show pain located in the lateral deltoid. A patient with a full-thickness tear may often show compromised strength in a shoulder’s active mid-arc abduction and resisted external rotation with elbow flexed. A partial tear might not show weakness. Atrophy of the infraspinatus or supra-spinatus muscles is sometimes seen if a patient has a long-standing injury, i.e. several weeks old.
Plain x-rays are of little use.
Historically, the mechanism of injury, i.e. falling on an outstretched arm or repetitive and excessive use of the shoulder as in pitching a baseball or serving a tennis ball, are also helpful clues. Pain is aggravated by activities such as combing one’s hair or reaching for a wallet in the back pocket. Because they have difficulty finding a comfortable position, patients often have trouble sleeping.
Both MRI and ultrasound are accurate in the evaluation of the Rotator cuff. [6]
With regard to treatment, a 2007 Cochrane study concluded, “There were no randomised controlled trials comparing conservative to surgical treatment. From two studies, open surgical repair is superior to arthroscopic debridement/cleaning of the joint in rotator cuff tears for overall improvement at five year and nine year follow-up. The limited data suggests favouring conservative interventions as less invasive and less expensive than surgery.” [7]
National guidelines for surgical repairs of the shoulder
There is a national guideline for all surgical repairs of the shoulder that summarizes a broad, general consesus. [8]
