From Wikipedia, the free encyclopedia - View original article
|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|
Rotator cuff tears are tears of one or more of the four tendons of the 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 torn. Of the four tendons, the supraspinatus is most frequently torn as it passes below the acromion; the tear usually occurs at its point of insertion onto the humeral head at the greater tubercule.
The main functions of the cuff are to stabilize the glenohumeral joint and rotate the humerus outward. When shoulder trauma occurs, these functions can be attenuated, therefore suggesting a rotator cuff tear. Since individuals are highly dependent on the shoulder for many activities, overuse and overbearing of the muscles can lead to tears, with the vast majority of these tears occurring in the supraspinatus tendon.
Many rotator cuff tears cause no pain nor produce any symptoms, tears are known to have an increasing incidence with increasing age. The most frequent cause of rotator cuff damage is age related degeneration and less frequently by sports injuries or trauma. Partial and full thickness tears have been found on post mortem studies and on MRI studies, in people who do not have a history of shoulder pain or symptoms.
There are two main causes of rotator cuff tears: injury (acute) and degeneration (chronic). The mechanisms involved can be categorized as either extrinsic or intrinsic.
Chronic tears are symptomatic of extended periods of use in conjunction with other factors such as poor biomechanics or muscular imbalance. Most tears are the result of a wearing down of the tendon that occurs slowly over time. This degeneration naturally occurs as we age. Rotator cuff tears are more common in the dominant arm. Having a rotator cuff tear in one shoulder indicates an increased risk of a tear in the opposing shoulder, despite lack of pain or other symptoms. Several factors contribute to degenerative, or chronic, rotator cuff tears. Repetitive stress is the most significant factor involved in degeneration of the rotator cuff. Repetitive stress consists of repeating the same shoulder motions frequently, such as overhead throwing, rowing, and weightlifting. Many jobs that require frequent shoulder movement as a requirement such as lifting and overhead movements also contribute to degeneration.
Another factor that is prevalent in older populations is a lack of blood supply. As we get older our circulation to our rotator cuff tendons decreases, impairing the natural ability of our body to repair tendon damage. This can ultimately lead to or contribute to rotator cuff tears.
The final common factor is impingement syndrome. Impingement syndrome is the most common non-sport related rotator cuff injury. If the supraspinatus tendon passes beneath the acromion, the bone on top of the shoulder, the tendon and the lubricating tissue, or the bursa, is then pinched when the arm is raised into a forward or upward position. Repetitive impingement can make the tendons and the bursa inflamed, resulting in the disease referred to as impingement syndrome.
Acute tears occur due to a sudden, high stress motion or impact, such as if you fall down on your outstretched arm or lift something too heavy with a jerking motion. This type of tear can also occur with other shoulder injuries, such as a broken collarbone or dislocated shoulder.
One of the most well documented anatomical factors is the morphologic characteristics of the acromion. Hooked, curved, and laterally sloping acromions are strongly associated with cuff tears and may contribute by causing tractional damage to the tendon. On the other hand, flat acromions may have a insignificant involvement in cuff disease and consequently are often best treated conservatively. The development of these different acromial shapes is likely both genetically inherited and acquired from other causes. With acquired causes, only age has been positively correlated to progression from a flat to a curved or hooked acromion. The nature of mechanical activities, such as sports involving the shoulder, along with frequency and intensity of such a sport may be responsible for the adverse development. Sports such as bowling in cricket, swimming, tennis, baseball, and kayaking are primarily responsible. Moreover, 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 encompass the range of 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, the humerus, and the scapula that features the glenoid fossa, acromion and coracoid processes. These three bones create a ball-and-socket joint, also known as the glenohumeral joint, that give the shoulder its wide range of motion encompassing three different planes. In order for this joint to be operational ligaments, muscles, and tendons help support the bone; keeping it in place.
Ligaments and joints are formed from the connection between two bones that are adjacent. Examples of both ligaments and joints are represented by the glenohumeral, acromiclavicular, and sternoclavicular regions.
The major muscle groups of the rotator cuff are the supraspinatus, subscapularis, infraspinatus, and teres minor that contribute to the stability of the shoulder. The cuff adheres to the glenohumeral capsule and attaches to the humeral head. The only individualized structures at the humeral head are the upper edge of the subscapularis tendon and anterior edge of the supraspinatus muscle, which delineate a triangular space called the rotator interval. The cuff plays two main roles: it stabilizes the glenohumeral joint and rotates the humerus outward. The cuff centers the humeral head in the glenoid cavity via passive effects and, more importantly, via active multidirectional effects. In other words, the cuff prevents upward migration of the humeral head caused by the pull of the deltoid muscle at the beginning of arm elevation. Furthermore, two cuff muscles, the infraspinatus and the teres minor, are the only muscles that ensure 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 torn 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 tears, full thickness tears and full thickness tears with complete detachment of the tendons from bone.
Shoulder pain is variable and does not always correspond to the size of the tear.
For surgical purposes classifying the tendon further is needed in order to determine the correct repair strategy. Neer generalized the concept of rotator cuff disease in 3 stages. 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. Before surgery every aspect of the shoulder needs to be taken into account. Therefore, it has further been described depending on the tear 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). And still further measurements are taken to classify the acromiohumeral distance, acromial shape, fatty infiltration or degeneration of muscles, muscle atrophy, tendon retraction, vascular proliferation, chondroid metaplasia, and calcification. Age-related degeneration of thinning and disorientation of the collagen fibers, myxoid degeneration, and hyaline degeneration also need to be taken into consideration before a surgery plan is implemented.
Tears are also sometimes classified as acute, subacute, and chronic based on the trauma that caused the injury:
Diagnosis is based upon a physical assessment and a detailed history of the patient, including descriptions of previously participated activities and acute or chronic symptoms experienced. The physical examination of a shoulder deals with a systematic approach constituting inspection, palpation, range of motion, strength testing, and neurological testing. The shoulder will be examined to see whether it is tender in any area or whether there is a deformity. Since most cervical pain is commonly mistaken for shoulder pain, the physical examination should include a thorough assessment of the cervical spine in order to eliminate other contradictions such as a "pinched nerve", osteoarthritis or rheumatoid arthritis.
Common medical studies used in diagnosing a rotator cuff tear include X-ray, MRI, double-contrast arthrography, and ultrasound techniques. A normal rotator cuff tear usually goes undetected with an X-ray, although bone spurs, which can pinch the rotator cuff tendons and result in a tear, can be captured. Moreover, if bone spurs are present, it suggests 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. Arthrography and ultrasound are used, but depend heavily on the experience of a radiologist. The most effective and common diagnosis tool is magnetic resonance imaging (MRI), which can sometimes tell how large the tear is, 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 correct use of diagnostic tests is an important component of effective medical practice. X-rays cannot directly reveal tears of the rotator cuff as the tendon is made of soft tissue and not bone. Normal x-rays cannot rule out a torn or damaged rotator cuff. Indirect evidence of rotator cuff pathology can be seen on x-ray 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. Bone spurs may also be seen on the underside of the acromion. These types of bone spurs were thought to cause direct fraying of the rotator cuff from contact friction, a concept currently in controversy.
Symptoms of a rotator cuff tear may advance instantly after a trauma (acute) or develop gradually, yet persistently over time (chronic).
Acute injuries are not as frequent as chronic rotator cuff disease. Acute tears occur following bouts of forcefully raising the arm against resistance, which are evident during weight lifting. In addition, falling forcefully on the shoulder can elicit acute symptoms. Traumatic rotator cuff tears predominantly affect the supraspinatus tendon or the rotator interval. These acute symptoms include severe pain that radiates through the arm, tenderness at the site of injury, and limited range of motion, specifically during abduction motions of the shoulder.
Chronic tears occur among individuals that constantly participate in overhead activities, such as pitching or swimming. Also, these tears can develop from shoulder tendinitis or rotator cuff disease. This disease involves a wide range of pathology of the rotator cuff tendons. Symptoms that persist as a result of a chronic rotator cuff tears are sporadic worsening of pain, debilitation and atrophy of the muscles, noticeable pain during rest, crackling sensations 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 can be due to many causes, symptoms may reflect pathology outside of the shoulder which cause referred pain to the shoulder from sites such as 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.
Some areas of the rotator cuff tendons have poor blood supply.
Park et al. 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, 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) or ultrasound are comparable to examine the rotator cuff. The MRI can reliably detect most full thickness tears, 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, called an MR-arthrogram may help to confirm the diagnosis. With larger tears, a false positive, is less likely. However, a normal MRI cannot fully rule out a small tear (a false negative). Partial thickness tears are not as reliably detected on MRI. The MRI is sensitive in identifying tendon degeneration (tendinopathy), however, the MRI may not be able to reliably distinguish between a degenerative tendon and a partially torn tendon. Magnetic resonance arthrography can improve the differentiation of rotator cuff degeneration from partial or complete rotator cuff tears. Stetson et al., in 2005 showed a false-negative rate of 9% and sensitivity at 91%, the authors concluded that magnetic resonance arthrography was a very reliable test in the detection of partial-thickness rotator cuff tears. The routine use of magnetic resonance arthrography was not advised and the test was reserved in cases where the diagnosis was unclear.
Ultrasound studies have also been reported as a means of identifying rotator cuff tears. Unlike x-rays which require exposure to radiation and MRI studies which are costly, ultrasound studies have been advocated as an alternative, when read by experienced clinicians. When ultrasonography and magnetic resonance imaging studies have been read by investigators with comparable experience, 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.
Clinicians and patients are advised to use clinical judgement and not rely on MRI images or x-rays to determine the cause of shoulder pain or treatment, since rotator cuff tears are found in people without any pain or symptoms. The role of x-rays, MRI and ultrasound, are part of the entire clinical picture and serve 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.
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.
Since many patients with partial tears and some even with complete tears can respond to non-operative management, generally conservative care is offered first. If a significant trauma such as a shoulder dislocation, or fracture, or high energy force is known to have been followed by complete to near complete loss of rotator cuff-mediated motion and strength, then an operative work-up is initiated with plans to proceed to surgery for repair, if confirmatory.
Patients with pain and maintenance of reasonable function are generally treated for pain relief at first. Non-operative treatment of shoulder pain thought to be related to the rotator cuff, or a tear of the rotator cuff, includes oral medications that provide pain relief such as anti-inflammatory medications, topical pain relievers such as cold packs and if warranted a subacromial cortisone/local anesthetic injection to block the pain and start direct instillation of anti-inflammatory treatment. An alternative to needle injection is iontophoresis, a battery powered patch which phoresis the medication to the target tissue. A sling may be offered for comfort for a day or two, with the awareness that the shoulder can become stiff with prolonged immobilization, which is to be avoided. Early physical therapy may afford pain relief with modalities (ex. iontophoresis) and help to maintain motion. Ultrasound treatment is not efficacious. As pain decreases, strength deficiencies and biomechanical errors can be corrected.
A non-operative or conservative physical therapy treatment program begins with preliminary rest and restriction from engaging in the event which caused the injury itself. Frequently the duration of rest is too short. Under normal situations, inflammation can usually be controlled within 1 to 2 weeks, using NSAIDs 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 1 to 2 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 performed by the patient as a part of the motion program. Codman exercises are renowned sources of motion using the pendulum to "permit the patient to abduct the arm by gravity, the supraspinatus remains relaxed, and no fulcrum is required," which is widely practiced in clinics. 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 2 to 3 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 the tendon in . 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, 1-m-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 nonoperative 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 operative management.
If conservative treatments have yielded poor results, surgery is considered to repair the torn tendons. Surgery is designated in patients under 60 years of age, full thickness tear demonstrated clinically, failure to improve after 6–8 weeks of physical therapy, and activity levels requiring use of the shoulder.
There are several surgical options for treatment of a rotator cuff tear. The exact type of surgery may depend on factors including the degree of tendon disruption, location of the tear, patients preferred activities, and presence or absence of bone spurs that may be contributing to the tear (ehealthmd.com). The three general approaches of surgical repairs are arthroscopic repair, mini-open repair, 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. Arthroscopic results now match open surgical techniques, and allow for a more thorough evaluation of the shoulder at the time of surgery, increasing the diagnostic value of the procedure, as several 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 than does open surgery.
If there is a bone spur that instigated the rotator cuff tear, arthroscopic repair, open repair (6–10 cm incision), or mini-open repair (3–5 cm incision) will often 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, hoping to relieve pressure on the rotator cuff in certain conditions and promote healing and recovery. Although subacromial decompression may be beneficial to partial and full thickness tears, this procedure does not consist of physically repairing the tears. Arthroscopic decompression has more recently been combined with "mini-open" repair of the rotator cuff, which allows for the repair of the cuff without disruption of the deltoid origin. A sole decompression approach tends to degrade with time, but combining repairing of the tear with decompression produces better results.
A complete full-thickness rotator cuff tear, the most severe, involves mending the torn rotator cuff by suturing the tissues back together. The usual method that is currently in use, is to place an anchor in the bone of the natural attachment site, and suture the torn tendon end back down to the bone from which it originally tore away. If the tissue quality is poor the surgeon might use a mesh (collagen, Artelon or other degradable material) 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 3–6 months, with a sling being worn for the first 1–6 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 10 year follow-up. However, the same study demonstrated ongoing and progressive fatty atrophy and re-tears of the rotator cuff. 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. In the first stage, the arm is immobilized so that the muscle can heal. After the surgeon decides that the arm is healed enough to be exercised, a therapist assists with passive exercises to slowly strengthen the muscle. Gradually the arm is exercised normally, strengthening it further.
Rotator cuff is a group of muscles and tendons that allow for flexibility and stability. Long-term abuse to the shoulder joint may limit range of motion and productivity due to daily wear and tear of the muscles. This can be prevented by regular shoulder exercises to maintain strength and flexibility, utilizing proper form when lifting or moving heavy weights, and resting the shoulder when experiencing pain. If pain is experienced, apply cold packs and heat pads to the inflamed area. Shoulder-strengthening program can help prevent injuries from occurring. It is equally important to work out the back and shoulder girdle muscles as it is to work the chest, shoulder and upper arm. Having a history of rotator cuff injuries, avoid sports that require tremendous amount of arm movement such as basketball, baseball, tennis, swimming or hockey. If symptoms of pain arise, it is important to rest the shoulder muscles and tendons. For example, taking breaks at work if required to lift or reach for things.
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 5-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.
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.
|Wikimedia Commons has media related to: Rotator cuff tear|