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|Rotator cuff tear|
|Classification and external resources|
Muscles on the dorsum of the scapula, and the Triceps brachii.
|ICD-9||726.1 727.61, 840.4|
|eMedicine||radio/894 pmr/125 radio/889 sports/115|
|Rotator cuff tear|
|Classification and external resources|
Muscles on the dorsum of the scapula, and the Triceps brachii.
|ICD-9||726.1 727.61, 840.4|
|eMedicine||radio/894 pmr/125 radio/889 sports/115|
A rotator cuff tear is a tear of one or more of the tendons of the four rotator cuff muscles of the shoulder. A rotator cuff 'injury' can include any type of irritation or overuse of those muscles or tendons and is among the most common conditions affecting the shoulder.
The tendons of the rotator cuff, not the muscles, are most commonly involved and of the four, the supraspinatus most frequently, as it passes below the acromion. Such a tear usually occurs at its point of insertion onto the humeral head at the greater tubercle.
The cuff is responsible for stabilizing the glenohumeral joint and rotating the humerus outward (external rotation). When shoulder trauma occurs, these functions can be compromised. Because individuals are highly dependent on the shoulder for many activities, overuse of the muscles can lead to tears, the vast majority again occurring in the supraspinatus tendon.
Many rotator cuff tears are asymptomatic. They are known to increase in frequency with age and the most common cause is age-related degeneration and, less frequently, sports injuries or trauma. Both partial and full thickness tears have been found on post mortem and MRI studies in those without any history of shoulder pain or symptoms. However, the most common presentation is shoulder pain or discomfort. This may occur with activity, particularly shoulder activity above the horizontal position, but may also be present at rest in bed. Pain-restricted movement above the horizontal position may be present, as well as weakness with shoulder flexion and abduction.
There are two main causes, injury (acute) and degeneration (chronic and cumulative), and the mechanisms involved can be either extrinsic or intrinsic or, probably most commonly, a combination of both.
The amount of stress needed to tear a rotator cuff tendon acutely will depend on the underlying condition of the tendon prior to the stress. In the case of a healthy tendon, the stress needed will be high such as a fall on the outstretched arm. This stress may occur coincidentally with other injuries such as a dislocation of the shoulder, or separation of the acromioclavicular joint. In the case of a tendon with pre-existing degeneration, the force may be surprisingly modest such as a sudden lift, particularly with the arm above the horizontal position.
Chronic tears are indicative of extended use in conjunction with other factors such as poor biomechanics or muscular imbalance. Ultimately, most are the result of wear that occurs slowly over time as a natural part of aging. They are more common in the dominant arm but a tear in one shoulder signals an increased risk of a tear in the opposing shoulder. Several factors contribute to degenerative, or chronic, rotator cuff tears of which repetitive stress is the most significant. This stress consists of repeating the same shoulder motions frequently, such as overhead throwing, rowing, and weightlifting. Many jobs that require frequent shoulder movement such as lifting and overhead movements also contribute.
Another factor in older populations is impairment of blood supply. With age, circulation to the rotator cuff tendons decreases, impairing natural ability to repair, ultimately leading to, or contributing to, tears.
The final common factor is impingement syndrome, the most common non-sport related injury and which occurs when the tendons of the rotator cuff muscles become irritated and inflamed while passing through the subacromial space beneath the acromion. This relatively small space becomes even smaller when the arm is raised in a forward or upward position. Repetitive impingement can inflame the tendons and bursa, resulting in the syndrome.
Well documented, anatomical, factors include the morphologic characteristics of the acromion. Hooked, curved, and laterally sloping acromia are strongly associated with cuff tears and may cause tractional damage to the tendon. Conversely, flat acromia may have an insignificant involvement in cuff disease and consequently may be best treated conservatively. The development of these different acromial shapes is likely both genetic and acquired. In the latter case, only age has been positively correlated with progression from flat to curved or hooked. The nature of mechanical activities, such as sports involving the shoulder, along with frequency and intensity of such sports, may be responsible for the adverse development. Sports such as bowling in cricket, swimming, tennis, baseball, and kayaking, are most frequently implicated. However, a progression to a hooked acromion may simply be an adaptation to an already damaged, poorly balanced, rotator cuff that is creating increasing stress on the coracoacromial arch. Other anatomical factors that may have significance include os acromiale and acromial spurs. Environmental factors implicated include increasing age, shoulder overuse, smoking, and any medical condition that impairs the inflammatory and healing response, such as diabetes mellitus.
Intrinsic factors refer to injury mechanisms that occur within the rotator cuff itself. The principal is a degenerative-microtrauma model, which supposes that age-related tendon damage compounded by chronic microtrauma results in partial tendon tears that then develop into full rotator cuff tears. As a result of repetitive microtrauma in the setting of a degenerative rotator cuff tendon, inflammatory mediators alter the local environment, and oxidative stress induces tenocyte apoptosis causing further rotator cuff tendon degeneration. A neural theory also exists that suggests neural overstimulation leads to the recruitment of inflammatory cells and may also contribute to tendon degeneration.
Bone is living tissue that makes up the body's skeleton providing shape and support. The bones that form the shoulder are the clavicle, humerus, and scapula, the latter providing the glenoid fossa, acromion and coracoid processes. These three bones create a ball-and-socket glenohumeral joint, that give the shoulder its wide range of motion in three different planes. In order for this joint to be operational, ligaments, muscles, and tendons must support the bone and maintain the relationship of one to another. Joints are formed by the ligamentous connection between two adjacent bones. Examples of both ligaments and joints are demonstrated by the glenohumeral, acromiclavicular, and sternoclavicular regions.
The muscles of the rotator cuff are supraspinatus, subscapularis, infraspinatus, and teres minor, all contributing to the stability of the shoulder. The cuff adheres to the glenohumeral capsule and attaches to the humeral head. The upper edge of the subscapularis tendon and anterior edge of the supraspinatus muscle, delineate a triangular space at the humeral head called the rotator interval. The cuff plays two main roles:
The cuff centers the humeral head in the glenoid cavity and prevents upward migration of the humeral head caused by the pull of the deltoid muscle at the beginning of arm elevation. Furthermore, the infraspinatus and the teres minor, along with the anterior fibers of the deltoid muscle, are responsible for external rotation of the arm.
The four tendons of these muscles converge to form the rotator cuff tendon. These tendinous insertions along with the articular capsule, the coracohumeral ligament, and the glenohumeral ligament complex, blend into a confluent sheet before insertion into the humeral tuberosities. The insertion site of the rotator cuff tendon at the greater tuberosity is often referred to as the footprint. The infraspinatus and teres minor fuse near their musculotendinous junctions, while the supraspinatus and subscapularis tendons join as a sheath that surrounds the biceps tendon at the entrance of the bicipital groove. The supraspinatus is most commonly involved in a rotator cuff tear.
The insertions sites of the supraspinatus and infraspinatus tendons have been further described as a five-layer structure providing a glimpse into the various types of tears that can form given the different fiber characteristics of each layer.
Tears of the rotator cuff tendon are described as partial or full thickness, and full thickness with complete detachment of the tendons from bone.
Shoulder pain is variable and may not be proportional to the size of the tear.
Surgical considerations. Neer promoted the concept of three stages of rotator cuff disease. Stage I, according to Neer, occurred in those younger than 25 years and involved edema and hemorrhage of the tendon and bursa. Stage II involved tendinitis and fibrosis of the rotator cuff in 25 to 40-year-olds. Stage III involved tearing of the rotator cuff (partial or full thickness) and occurred in those older than 40 years. For surgical purposes, tears are also described by location, size or area, and depth. Further subclasses include the acromiohumeral distance, acromial shape, fatty infiltration or degeneration of muscles, muscle atrophy, tendon retraction, vascular proliferation, chondroid metaplasia, and calcification. Again, in surgical planning, age-related degeneration of thinning and disorientation of the collagen fibers, myxoid degeneration, and hyaline degeneration are considered.
However, for simplicity, tears are sometimes classified based on the trauma that caused the injury:
Diagnosis is based upon physical assessment and history, including description of previous activities and acute or chronic symptoms. A systematic, physical examination of the shoulder comprises inspection, palpation, range of motion, provocative tests to reproduce the symptoms, neurological examination, and strength testing. The shoulder should also be examined for tenderness and deformity. Since pain arising from the neck is frequently 'referred' to the shoulder, the examination should include an assessment of the cervical spine looking for evidence suggestive of a pinched nerve, osteoarthritis or rheumatoid arthritis.
Diagnostic modalities, dependent on circumstances, include x-ray, MRI, MR arthrography, double-contrast arthrography, and ultrasound. Although MR arthrography is currently considered the gold standard, ultrasound may be most cost-effective. Usually, a tear will be undetected by x-ray, although bone spurs, which can impinge upon the rotator cuff tendons, may be visible. Such spurs suggest chronic severe rotator cuff disease. Double-contrast arthrography involves injecting contrast dye into the shoulder joint to detect leakage out of the injured rotator cuff and its value is influenced by the experience of the operator. The commonest diagnostic tool is magnetic resonance imaging (MRI), which can sometimes indicate the size of the tear, as well as its location within the tendon. Furthermore, MRI enables the detection or exclusion of complete rotator cuff tears with reasonable accuracy and is also suitable to diagnose other pathologies of the shoulder joint.
The logical use of diagnostic tests is an important component of effective clinical practice. X-rays cannot directly reveal tears of the rotator cuff, a 'soft tissue', and consequently, normal x-rays cannot exclude a damaged cuff. However, indirect evidence of pathology may be seen in instances where one or more of the tendons have undergone degenerative calcification (calcific tendinitis). Also, large tears of the rotator cuff may allow the humeral head to migrate upwards (high riding humeral head) which may be visible on x-ray. Prolonged contact between a high-riding humeral head and the acromion above it, may lead to x-rays findings of wear on the humeral head and acromion and secondary degenerative arthritis of the glenohumeral joint (the ball and socket joint of the shoulder), called cuff arthropathy, may follow. Incidental x-ray findings of bone spurs at the adjacent acromio-clavicular joint (A-C joint) may show a bone spur growing from the outer edge of the clavicle downwards towards the rotator cuff. Spurs may also be seen on the underside of the acromion, once thought to cause direct fraying of the rotator cuff from contact friction, a concept currently regarded as controversial.
Clinical judgement, rather than over reliance on MRI or any other modality, is strongly advised in determining the cause of shoulder pain, or planning its treatment, since rotator cuff tears are also found in some without pain or symptoms. The role of x-ray, MRI and ultrasound, is adjunctive to clinical assessment and serves to confirm a diagnosis provisionally made by a thorough history and physical examination. Over-reliance on imaging may potentially lead to over-treatment or distraction from the true underlying problem.
Symptoms may occur immediately after trauma (acute) or develop over time (chronic).
Acute injury is less frequent than chronic disease but may follow bouts of forcefully raising the arm against resistance, as occurs in weight lifting, for example. In addition, falling forcefully on the shoulder can cause acute symptoms. These traumatic tears predominantly affect the supraspinatus tendon or the rotator interval and symptoms include severe pain that radiates through the arm, and limited range of motion, specifically during abduction of the shoulder. Chronic tears occur among individuals who constantly participate in overhead activities, such as pitching or swimming, but can also develop from shoulder tendinitis or rotator cuff disease. Symptoms arising from chronic tears include sporadic worsening of pain, debilitation and atrophy of the muscles, noticeable pain during rest, crackling sensations (crepitus) when moving the shoulder, and inability to move or lift the arm sufficiently, especially during abduction and flexion motions.
Pain in the anterolateral aspect of the shoulder is not specific to the shoulder, and may arise from, and be referred from, the neck, heart or gut.
Patient history will often include pain or ache over the front and outer aspect of the shoulder, pain aggravated by leaning on the elbow and pushing upwards on the shoulder (such as leaning on the armrest of a reclining chair), intolerance of overhead activity, pain at night when lying directly on the affected shoulder, pain when reaching forward (e.g. unable to lift a gallon of milk from the refrigerator). Weakness may be reported, but is often masked by pain and is usually found only through examination. With longer standing pain, the shoulder is favored and gradually loss of motion and weakness may develop which, due to pain and guarding, are often unrecognized by the patient and only brought to attention during examination.
Primary shoulder problems may cause pain over the deltoid muscle intensified by abduction against resistance - the impingement sign. This signifies pain arising from the rotator cuff but cannot distinguish between inflammation, strain, or tear. Patients may report that they are unable to reach upwards to brush their hair or to to lift a food can from an overhead shelf.
It has been suggested that there is no single physical examination test that distinguishes reliably between bursitis, partial-thickness, and full-thickness tears. On the contrary, a combination of tests seems to provide the most accurate diagnosis. For impingement, these tests include the Hawkins-Kennedy impingement sign in which the examiner medially rotates the patient's flexed arm forcing the supraspinatus tendon against the coracoacromial ligament and so producing pain if the test is positive a positive painful arc sign, and weakness in external rotation with the arm at the side. For the diagnosis of full thickness rotator cuff tear, the best combination appears to include once more the painful arc and weakness in external rotation, and in addition, the drop arm sign. This test is also known as Codman's test. The arm is raised to the side to 90° by the examiner. The patient then attempts to look to lower the arm back to neutral, palm down. If the arm drops suddenly or pain is experienced, the test is considered positive
Magnetic resonance imaging (MRI) and ultrasound are comparable in efficacy and helpful in diagnosis although both have a false positive rate of 15 - 20%. MRI can reliably detect most full-thickness tears although very small pin-point tears may be missed. In such situations, an MRI combined with an injection of contrast material, an MR-arthrogram, may help to confirm the diagnosis. It should be realized that a normal MRI cannot fully rule out a small tear (a false negative) while partial-thickness tears are not as reliably detected. While MRI is sensitive in identifying tendon degeneration (tendinopathy), it may not reliably distinguish between a degenerative tendon and a partially torn tendon. Again, magnetic resonance arthrography can improve the differentiation. An overall sensitivity of 91% (9% false negative rate) has been reported indicating that magnetic resonance arthrography is reliable in the detection of partial-thickness rotator cuff tears. However, its routine use is not advised since it involves entering the joint with a needle with potential risk of infection. Consequently, the test is reserved for cases in which the diagnosis remains unclear.
Musculoskeletal ultrasound has been advocated by experienced practitioners, avoiding the radiation of x-ray and the expense of MRI while demonstrating comparable accuracy to MRI for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears. This modality can also reveal the presence of other conditions that may mimic rotator cuff tear at clinical examination, including tendinosis, calcific tendinitis, subacromial subdeltoid bursitis, greater tuberosity fracture, and adhesive capsulitis. However, MRI provides more information about adjacent structures in the shoulder such as the capsule, glenoid labrum muscles and bone and these factors should be considered in each case when selecting the appropriate study.
As part of clinical decision making, a simple, minimally invasive, in-office procedure may be performed, the rotator cuff impingement test. A few cc's of a local anesthetic and an injectable corticosteroid are injected into the subacromial space to block pain and to provide anti-inflammatory relief. If pain disappears and shoulder function remains good, no further testing is pursued. The test helps to confirm that the pain arises from the shoulder primarily rather than referred from the neck, heart or gut.
If pain is relieved, the test is considered positive for rotator cuff impingement, of which tendinitis and bursitis are major causes. However, partial rotator cuff tears may also demonstrate good pain relief and so a positive response cannot rule out a partial rotator cuff tear. However, with demonstration of good, pain-free function, treatment will not change so the test is useful in helping to avoid over-testing or unnecessary surgery.
Those suspected of having a rotator cuff tear are potentially candidates for either operative or non-operative treatment. However, any individual may move from one group to the other based on clinical response and findings on repeated examination.
There is no evidence of benefit from early rather than delayed surgery, and many with partial tears and some with complete tears will respond to non-operative management. Consequently, many recommend initial, non-surgical management. However, early surgical treatment may be considered in significant (>1 cm-1.5 cm) acute tears or in young patients with full-thickness tears who have a significant risk for the development of irreparable rotator cuff changes.
Finally, a review of more than 150 published papers in 2010 concluded that there was no solid evidence that rotator cuff surgery benefited patients more than non-operative management, adding to management and treatment controversies.
Those with pain but reasonably maintained function are suitable for non-operative management. This includes oral medications that provide pain relief such as anti-inflammatory agents, topical pain relievers such as cold packs and, if warranted, subacromial corticosteroid/local anesthetic injection. An alternative to injection is iontophoresis, a battery-powered patch which "drives" the medication to the target tissue. A sling may be offered for short-term comfort, with the understanding that undesirable shoulder stiffness can develop with prolonged immobilization. Early physical therapy may afford pain relief with modalities (e.g. iontophoresis) and help to maintain motion. Ultrasound treatment is not efficacious. As pain decreases, strength deficiencies and biomechanical errors can be corrected.
A conservative physical therapy program begins with preliminary rest and restriction from engaging in activities which gave rise to symptoms. Normally, inflammation can usually be controlled within one to two weeks, using a non-steroidal anti-inflammatory drug (NSAID) and subacromial steroid injections to decrease inflammation, to the point that pain has been significantly decreased to make stretching tolerable. After this short period, rapid stiffening and an increase in pain can result if sufficient stretching has not been implemented.
A gentle, passive range-of-motion program should be started to help prevent stiffness and maintain range of motion during this resting period. Exercises, for the anterior, inferior, and posterior shoulder, should be part of this program. Codman exercises (giant, pudding-stirring), to "permit the patient to abduct the arm by gravity, the supraspinatus remains relaxed, and no fulcrum is required," are widely used. The use of NSAIDs, hot and cold packs, and physical therapy modalities, such as ultrasound, phonophoresis, or iontophoresis, can be instituted during this stretching period, if effective. Corticosteroid injections are recommended two to three months apart with a maximum of three injections. Multiple injections (four or more) have been shown to compromise the results of rotator cuff surgery which result in weakening of the tendon. However, before any rotator cuff strengthening can be started, the shoulder must have a full range of motion.
After a full, painless range of motion is achieved, the patient may advance to a gentle strengthening program. Rockwood coined the term orthotherapy to describe this program which is aimed at creating an exercise regimen that initially gently improves motion, then gradually improves strength in the shoulder girdle. Each patient is given a home therapy kit, which includes elastic bands of six different colors and strengths, a pulley set, and a three piece, one meter-long stick. The program is customized, fitting the needs of the individual and altering when necessary. Participants are asked to utilize their exercise program whether at home, work, or traveling.
There are several instances in which non-operative treatment would not be suggested:
These patients may need to be treated operatively because rotator cuff repair is necessary for restoration of the normal strength required to return to the preoperative, competitive level of function. Finally, those who do not respond to, or are unsatisfied with, conservative treatment should seek a surgical opinion.
If satisfactory function has not been regained with conservative treatment, surgery is considered and the following guidelines apply:
The three general surgical approaches are arthroscopic, mini open, and open-surgical repair. In the recent past small tears were treated arthroscopically, while larger tears would usually require an open procedure. Advances in arthroscopy now allow arthroscopic repair of even the largest tears, and arthroscopic techniques are now required to mobilize many retracted tears. The results match open surgical techniques, while permitting a more thorough evaluation of the shoulder at time of surgery, increasing the diagnostic value of the procedure, as other conditions may simultaneously cause shoulder pain. Arthroscopic surgery also allows for shorter recovery time although there does not appear to be significant difference in postoperative pain or pain medication use between arthroscopic and open surgical patients.
If there is a significant bone spur, any of the approaches may include an acromioplasty, a subacromial decompression, as part of the procedure. Subacromial decompression, removal of a small portion of the bone (acromion) that overlies the rotator cuff, aims to relieve pressure on the rotator cuff in certain conditions and promote healing and recovery. Although subacromial decompression may be beneficial in the management of partial and full-thickness tear repair, it does not repair the tear itself and arthroscopic decompression has more recently been combined with "mini-open" repair of the rotator cuff, allowing for the repair of the cuff without disruption of the deltoid origin. The results of decompression alone tend to degrade with time, but the combination of repair and decompression appears to be more enduring.
Repair of a complete, full-thickness, tear involves tissue suture. The method currently in favor is to place an anchor in the bone at the natural attachment site, with resuture of torn tendon to the anchor. If tissue quality is poor, mesh (collagen, Artelon or other degradable material) may be used to reinforce the repair. Repair can be performed through an open incision, again requiring detachment of a portion of the deltoid, while a mini-open technique approaches the tear through a deltoid splitting approach. The latter may cause less injury to muscle and produce better results. Contemporary techniques now use an all arthroscopic approach. Recovery can take as long as three–six months, with a sling being worn for the first one–six weeks.
Positive outcomes for surgical repair of severe tears of the rotator cuff have been shown on a ten-year followup study. However, progressive fatty atrophy and re-tears of the rotator cuff have also been noted and it has been suggested that MRI evidence of fatty atrophy prior to surgery is predicative of a poor surgical outcome. The issue of failure of surgical repair and poor conservative care outcomes caused by muscular atrophy continues to be vexing and the demonstration that mesenchymal stem cells can differentiate into skeletal muscle raises the question of a future bioengineering solution.
Rehabilitation after surgery consists of three stages. First, the arm is immobilized so that the muscle can heal. Second, when appropriate, a therapist assists with passive exercises to regain range of motion. Third, the arm is gradually exercised actively, with a goal of regaining and enhancing strength.
It is generally accepted that long-term overuse/abuse of the shoulder joint may limit range of motion and productivity due to daily wear and tear of the muscles and many public web sites offer preventive advice. (See external links) The recommendations usually include:
While people with rotator cuff tears may not have any noticeable symptoms, studies have shown that over time 40% will have enlargement of the tear over a five-year period. Of those whose tears enlarge, 20% have no symptoms while 80% eventually develop symptoms.
Epidemiological studies strongly support a relationship between age and cuff tear prevalence. In a recent study the frequency of such tears increased from 13% in the youngest group (aged 50–59 y) to 20% (aged 60–69 y), 31% (aged 70–79 y), and 51% in the oldest group (aged 80–89 y). This high rate of tear prevalence in asymptomatic individuals suggests that rotator cuff tears could be considered a "normal" process of aging rather than a result of an apparent pathological process.
In an autopsy study of rotator cuff tears, the incidence of partial tears was 28%, and of complete rupture 30%. Frequently, tears occurred on both sides and the frequency increased with age. The frequency was also higher in females. Other cadaver studies have noted intratendinous tears to be more frequent (7.2%) than bursal-sided (2.4%) or articular-sided tears (3.6%). However, clinically, articular-sided tears are found to be 2 to 3 times more common than bursal-sided tears and among a population of young athletes, articular-sided tears constituted 91% of all partial-thickness tears.
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