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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. A rotator cuff injury can include any type of irritation or damage to the rotator cuff muscles or tendons.
Rotator cuff tears are 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, with 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 also been found on post mortem and MRI studies in those without any history of shoulder pain or symptoms.
Acute tears occur as a result of a sudden, high stress motion or impact, such as a fall on the outstretched arm, or a heavy lift with a jerking motion. They can also occur in association with other shoulder injuries, such as a broken collarbone or dislocated shoulder.
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 factor. 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 the natural ability to repair, ultimately leading to, or contributing to, tears.
The final common factor is impingement syndrome, the most common non-sport related rotator cuff injury. This occurs when the tendons of the rotator cuff muscles become irritated and inflamed while passing through the subacromial space, the passage beneath the acromion. This is a relatively small space and becomes even smaller when the arm is raised into a forward or upward position. Repetitive impingement can make the tendons and the bursa inflamed, 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 contribute by causing 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. With acquired causes, 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 the injury mechanisms that occur within the rotator cuff itself. Chief among these 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 the 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. The tendinous insertions of the rotator cuff muscles 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 the most common muscle tendon involved in a rotator cuff tear.
This layered anatomy of the rotator cuff tendons provides a glimpse into the various types of tears that could form given the different fiber characteristics of each layer.
Tears of the rotator cuff tendon are described as partial thickness, 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.
For surgical purposes, Neer promoted the concept of three stages of rotator cuff disease. Stage I occurs in those younger than 25 years and involves edema and hemorrhage of the tendon and bursa. Stage II involves tendinitis and fibrosis of the rotator cuff in 25 to 40-year-olds. Stage III involves tearing of the rotator cuff (partial or full thickness) and occurs in those older than 40 years. Tears are also described by location (articular, bursal, complete), size or area (in mm2), and depth (grade 1, <3 mm deep; grade 2, 3–6 mm deep; grade 3, >6 mm deep). Further subclasses include the acromiohumeral distance, acromial shape, fatty infiltration or degeneration of muscles, muscle atrophy, tendon retraction, vascular proliferation, chondroid metaplasia, and calcification. Finally, age-related degeneration of thinning and disorientation of the collagen fibers, myxoid degeneration, and hyaline degeneration are considered in surgical planning.
Tears are also sometimes classified as acute, subacute, and chronic based on the trauma that caused the injury:
Diagnosis is based upon physical assessment and detailed history, including descriptions of previous activities and acute or chronic symptoms experienced. The 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. Pain arising from the neck is frequently 'referred' to the shoulder so the physical examination should include a thorough assessment of the cervical spine looking evidence suggestive of a pinched nerve, osteoarthritis or rheumatoid arthritis.
Diagnostic modalities, dependent on the circumstances, include x-ray, MRI, MR arthrography, double-contrast arthrography, and ultrasound. Although MR arthrography is currently considered the gold standard for imaging diagnosis, ultrasound may be most cost-effective because of its lower cost. Usually, a rotator cuff tear will be undetected by x-ray, although bone spurs, which can impinge upon the rotator cuff tendons, may be visible. Moreover, if bone spurs are present, chronic severe rotator cuff disease is suggested. Double-contrast arthrography involves injecting contrast dye into the shoulder joint to detect leakage out of the injured rotator cuff. Its value is dependent on 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 a reasonable accuracy and is also suitable to diagnose further 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). Large tears of the rotator cuff may allow the humeral head to migrate upwards (high riding humeral head) and this can be seen 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 the acromion and secondary degenerative arthritis of the glenohumeral joint (the ball and socket joint of the shoulder) may ensue called cuff arthropathy. 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 found in people without pain or symptoms. The role of x-ray, MRI and ultrasound, is adjunctive to clinical assessment and serves to confirm the diagnosis, which is provisionally made by a thorough history and physical examination. Over reliance on x-rays or MRI imaging may lead to over treatment or distraction from the true underlying problem.
Symptoms of a rotator cuff tear may occur immediately after trauma (acute) or develop gradually 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. This disease involves a wide range of pathology. Symptoms arising as a result of 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 to 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 missed by the patient and are only brought out during the examination.
Primary shoulder problems may cause pain over the deltoid muscle that is made worse by abduction against resistance, called the impingement sign. Impingement reflects pain arising from the rotator cuff but cannot distinguish between inflammation, strain, or tear. Patients may report their experience with the impingement sign when they report that they are unable to reach upwards to brush their hair or to reach in front to lift a can of beans up from an overhead shelf.
An evaluated eight well known physical examination tests to determine their diagnostic values to help distinguish between bursitis, partial-thickness rotator cuff tears, and full-thickness rotator cuff tears. The study concluded that "the best test" was a combination of tests. For the diagnosis of impingement disease the best combination of tests were a positive: Hawkins-Kennedy impingement sign (the physician medially rotates the patient's flexed arm: this forces the supraspinatus tendon against the coracoacromial ligament, and if there is pain, the test is positive), a positive painful arc sign, and weakness in external rotation with the arm at the side. To diagnose a full-thickness rotator cuff tear, the best combination of tests, when all three are positive: were the painful arc, the drop-arm sign, and weakness in external rotation.
Magnetic resonance imaging (MRI) and ultrasound are comparable in efficacy. MRI can reliably detect most full-thickness tears (although false positives are a serious problem (http://www.iasm.com/pdfs/PartialThicknesTearsoftheRotatorCuff-recommendationsf.pdf), although very small pin-point tears can be missed. If a small pin-point tear is suspected, 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. In these circumstances, magnetic resonance arthrography can improve the differentiation. Stetson et al. reported an overall sensitivity of 91% (9% false negative rate) and concluded that magnetic resonance arthrography was a very reliable test in the detection of partial-thickness rotator cuff tears. However, the routine use of magnetic resonance arthrography is not advised since it involves entering the joint with a needle with possible risk of infection and the test is reserved for those cases in which the diagnosis remains unclear.
Unlike x-rays which require exposure to radiation and MRI studies which are costly, ultrasound studies have been advocated as an alternative, when interpreted by experienced practitioners. When compared with magnetic resonance imaging studies, they have been shown to have comparable accuracy for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears. Ultrasound 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. The MRI provides more information about adjacent structures in the shoulder such as the capsule, glenoid labrum muscles and bone. These are factors to 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, called the rotator cuff impingement test. A few cc's of a local anesthetic and an injectable cortisone preparation are injected into the subacromial space to block pain and to provide anti-inflammatory relief. If the pain disappears and function remains good no further treatment or testing are pursued. The test helps to confirm that the pain arises from the shoulder primarily and is not referred pain from the neck, heart or gut.
It is thought[who?] that the cortisone helps diminish inflammation of the bursa that directly over lies the rotator cuff (sub-acromial bursitis). The test, if pain is relieved, is considered positive for rotator cuff impingement, of which tendinitis and bursitis are a part. However, partial rotator cuff tears may also have good pain relief and a good response cannot rule out a partial rotator cuff tear. In the face of good function and no pain, even with a partial rotator cuff tear, treatment would not change and the impingement test is useful in relief of pain and avoiding over testing or unnecessary surgery.
Patients suspected of having a rotator cuff tear are divided into two treatment groups initially: Each patient is initially a candidate for either operative or non-operative treatment, however patients are re-evaluated throughout the course of treatment and may move from one group to the other based on their clinical response and findings on repeated examination.
There is no evidence of better results from early rather than delayed surgery, and many with partial tears and some with complete tears will respond to non-operative management. For these reasons, many first recommend non-surgical management of rotator cuff tears. Early surgical treatment may be considered in acute tears that are significant (>1 cm-1.5 cm) or in young patients with full-thickness tears who have a significant risk for the development of irreparable rotator cuff changes.
Patients with pain, whose function is reasonably maintained, are suitable candidates for non-operative management which 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 the event which gave rise to the symptoms. Under normal situations, 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 of one to two weeks 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. Injections are recommended two to three months apart with a maximum of three injections. Multiple steroid injections (four or more) have been shown to compromise the results of rotator cuff surgery which result in weakening of the tendon. 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. The program 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 to each individual patient, fitting the needs of the patient and altering when necessary. Patients are asked to do all their home exercise program on their own whether that be at home, at work, or when traveling.
There are several instances in which non-operative treatment would not be suggested. The first is the 20 to 30-year-old active patient with an acute tear and severe functional deficit from a specific event. The second is the 30 to 50-year-old patient with an acute rotator cuff tear secondary to a specific event. The third instance is the highly competitive athlete who is primarily involved in overhead or throwing sports. These patients need to be treated operatively because rotator cuff repair is necessary for restoration of the normal strength required to return these athletes to the same competitive preoperative level of function. Patients who do not respond or are unsatisfied with conservative treatment should seek an opinion concerning surgery.
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 the procedure now allow arthroscopic repair of even the largest tears, and arthroscopic techniques are now required to mobilize many of the retracted tears. The results now match open surgical techniques, while permitting a more thorough evaluation of the shoulder at the time of surgery, increasing the diagnostic value of the procedure, as other conditions may simultaneously cause shoulder pain. Arthroscopic surgery allows for a shorter recovery time and predictably less pain in the first few days following the procedure.
If there is a significant bone spur, any of the major approaches may include an acromioplasty, a subacromial decompression, as part of the procedures. Subacromial decompression consists of removal of a small portion of the bone (acromion) that overlies the rotator cuff, aiming 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, this procedure does not physically repair the tear 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. Decompression alone tends to degrade with time, but the combination of repair and decompression appears to produce better results.
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, and resuture the torn tendon to the anchor. If the tissue quality is poor, mesh (collagen, Artelon or other degradable material) may be used to reinforce the repair. The repair can be performed through an open incision, again requiring detachment of a portion of the deltoid. The mini-open technique approaches the tear through a deltoid splitting approach. This seemingly causes less damage to the deltoid muscle and may produce better results. Modern techniques now use an all arthroscopic approach. Surgical recovery can take as long as three–six months, with a sling being worn for the first one–six weeks. Furthermore, in some severe cases where arthritis has developed, one option is to replace the shoulder joint, but these represent a small minority of cases.
Surgical outcomes for severe tears of the rotator cuff have been shown to be positive on a ten-year followup. However, the same study demonstrated ongoing and progressive fatty atrophy and re-tears of the rotator cuff. A study by Shen has shown that MRI evidence of fatty atrophy in the rotator cuff prior to surgery is predicative of a poor surgical outcome. To address this issue of failure of surgical repair and poor conservative care outcomes caused by muscular atrophy, bioengineering may be the answer. Mesenchymal stem cells have been shown to differentiate into skeletal muscle. Rotator cuff tears can be hereditary. Regardless of the method used, recent studies have shown that stable repairs of the rotator cuff give a more functional shoulder. Rotator cuff tears of the impingement type usually begin in patients in their 40's, and progress with time.
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 slowly strengthen the muscle. Third, the arm is gradually exercised normally, strengthening it further.
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. Many public web sites such as WebMD and Mayo Clinic offer preventive advice. 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.
There is no solid evidence that rotator cuff surgery benefits patients any more than non-surgical management. A percentage of patients never regain full range of motion after rotator cuff tear surgery.
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.
The vast majority of these tears occur in the supraspinatus tendon. In a study of 306 cadaveric shoulders, noted a 32% incidence of partial-thickness tears and a 19% incidence of full-thickness tears within the supraspinatus tendon. Cadaveric studies have noted intratendinous tears to actually be more frequent than bursal-sided or articular-sided tears. Partial-thickness tears were further grouped as bursal-sided (2.4%), intratendinous (7.2%), and articular-sided (3.6%). However, clinically, articular-sided tears are found to be 2 to 3 times more common than bursal-sided tears. In fact, among a population of young athletes, found that articular-sided tears constituted 91% of all partial-thickness tears. Partial-thickness tears of the subscapularis that were seen with concomitant lesions of the long head of the biceps in 30.4% of these tears have also merited attention. Therefore, lesions within the biceps tendon mandate close evaluation for related injury within the subscapularis tendon.
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