rotator cuff tear rotator cuff tear rotator cuff tendinopathy is a process of senescence. the pathophysiology is mucoid degeneration. most people develop rotator cuff tendinopathy within their lifetime. rotator cuff tearother namesrotator cuff injury, rotator cuff diseasesome of the muscles of the rotator cuff, with a tear in the supraspinatus musclespecialtyorthopedicssymptomsshoulder pain, weaknesstypespartial, completediagnostic methodbased on symptoms, examination, medical imagingdifferential diagnosissubacromial bursitis, rotator cuff tendinitis, impingement syndrometreatmentpain medication, specific exercises, surgeryfrequencycommon as part of rotator cuff tendinopathy, the tendon can thin and develop a defect. this defect is often referred to as a rotator cuff tear. acute, traumatic rupture of the rotator cuff tendons can also occur, but is less common. traumatic rupture of the rotator cuff usually involves the tendons of more than one muscle. this may limit people's ability to perform normal daily activities that require normal range of motion in the shoulder joint. clicking may also occur with movement of the arm. tears may occur as the result of a sudden force or gradually over time. risk factors include certain repetitive activities, smoking, a family history of the condition, increased age, and dominant arm. diagnosis is based on symptoms, examination, and medical imaging. the rotator cuff is made up of the supraspinatus, infraspinatus, teres minor, and subscapularis. the supraspinatus is the most commonly affected. treatment may include pain medication such as nsaids and specific exercises. it is recommended that people who are unable to raise their arm above 90 degrees after two weeks should be further assessed. surgery may be offered for acute ruptures and large attritional defects with good quality muscle. the benefits of surgery for smaller defects are unclear as of 2019. signs and symptoms location of the pain many rotator cuff tears have no symptoms. 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. however, symptoms of pain do not correlate with rotator cuff tear severity. abnormal mobility or function of the scapula (scapular dyskinesia) may be present and is related to lower functional scores; it unclear whether scapular dyskinesia is a cause, effect, or compensation for rotator cuff pathology. risk factors claims of rotator cuff tears by industry epidemiological studies strongly support a relationship between age and cuff tear prevalence, with the most common cause being age-related degeneration and, less frequently, sports injuries or trauma. those most prone to failed rotator cuff syndrome are people 65 years of age or older; and those with large, sustained tears. smokers, people with diabetes, individuals with muscle atrophy or fatty infiltration, and those who do not follow postoperative-care recommendations also are at greater risk. in a 2008 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). some risk factors, such as increased age and height, cannot be changed. increased body mass index is also associated with tearing. recurrent lifting and overhead motions are at risk for rotator cuff injury as well. this includes jobs that involve repetitive overhead work, such as carpenters, painters, custodians, and servers. people who play sports that involve overhead motions, such as swimming, water polo, volleyball, baseball, and tennis, and american football quarterbacks are at a greater risk of experiencing a rotator cuff tear. striking-based combat sports, such as boxing, also account for severe rotator cuff injuries in competitors, typically when their punches miss the target, or overusing the shoulder by throwing an excessively large number of punches. certain track-and-field activities, such as shot put and javelin throw are also of considerable risk, especially when athletes perform outdoors under cold weather conditions or neglect warming-up procedures; proper warm-up of the throwing and/or swinging arm can help reduce the stress on the musculature of the shoulder girdle. corticosteroid injections around the tendons increase the risk of tendon tear and delay tendon healing. mechanisms of injury the shoulder joint is made up of three bones: the shoulder blade (scapula), the collarbone (clavicle) and the upper arm bone (humerus). the acromion is a bony process at the end of the scapula the shoulder is a complex mechanism involving bones, ligaments, joints, muscles, and tendons. the two main causes are acute injury or chronic and cumulative degeneration of the shoulder joint. mechanisms can be extrinsic, intrinsic or a combination of both. the cuff is responsible for stabilizing the glenohumeral joint to allow abduction and rotation of the humerus. when trauma occurs, these functions can be compromised. because individuals are dependent on the shoulder for many activities, overuse can lead to tears, with the vast majority being in the supraspinatus tendon. the role of the supraspinatus is to resist downward motion, both while the shoulder is relaxed and carrying weight. supraspinatus tears usually occurs at its insertion on the humeral head at the greater tubercle. though the supraspinatus is the most commonly injured tendon in the rotator cuff, the other three can also be injured at the same time. acute tears the amount of stress needed to acutely tear a rotator cuff tendon will depend on the underlying condition of the tendon. if healthy, the stress needed will be high, such as with 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 more modest, such as with a sudden lift, particularly with the arm above the horizontal position. the type of loading involved with injury is usually eccentric, such as when two people are carrying a load and one lets go, forcing the other to maintain force while the muscle elongates. chronic tears 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. in older populations impairment of blood supply can also be an issue. with age, circulation to the rotator cuff tendons decreases, impairing natural ability to repair, increasing risk for tear. another potential contributing cause is impingement syndrome, the most common non-sports 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. extrinsic factors a flattened or hooked acromion can predispose a shoulder to rotator cuff impingement and tearing. well-documented anatomic factors include the morphologic characteristics of the acromion, a bony projection from the scapula that curves over the shoulder joint. hooked, curved, and laterally sloping acromia are strongly associated with cuff tears and may cause damage through direct traction on 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, there can be a progression from flat to curved or hooked with increasing age. repetitive mechanical activities such as sports and exercise may contribute to flattening and hooking of the acromion. cricket bowling, swimming, tennis, baseball, and kayaking are often implicated. progression to a hooked acromion could be an adaptation to an already damaged, poorly balanced rotator cuff with resultant stress on the coracoacromial arch. other anatomical factors include an os acromiale and acromial spurs. environmental factors include age, shoulder overuse, smoking, and medical conditions that affect circulation or impair the inflammatory and healing response, such as diabetes mellitus. intrinsic factors 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. surgical considerations depending upon the diagnosis, several treatment alternatives are available. they include revision repair, non-anatomic repair, tendon transfer, and arthroplasty. when possible, surgeons make tension-free repairs in which they use grafted tissues rather than stitching to reconnect tendon segments. this can result in a complete repair. other options are a partial repair, and reconstruction involving a bridge of biologic or synthetic substances. partial repairs are typically performed on retracted cuff tears. tendon transfers are prescribed for young, active cuff-tear individuals who experience weakness and decreased range of motion, but little pain. the technique is not considered appropriate for older people or those with pre-operative stiffness or nerve injuries. people diagnosed with glenohumeral arthritis and rotator cuff anthropathy have the alternative of total shoulder arthroplasty, if the cuff is largely intact or repairable. if the cuff is incompetent, a reverse shoulder arthroplasty is available and, although not as robust a prosthesis, does not require an intact cuff to maintain a stable joint. diagnosis a complete tear of the supraspinatus resulting in a shift upwards of the head of the humerus 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. 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. 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 most common 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 for