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.
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.
Rotator cuff tendinopathy is, by far, the most common reason people seek care for shoulder pain. Pain related to rotator cuff tendinopathy is typically on the front side of the shoulder, down to the elbow, and worse reaching up or back. Diagnosis is based on symptoms and examination. Medical imaging is used mostly to plan surgery and is not needed for diagnosis.
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. Indeed, a 2025 study in BMJ concluded that arthroscopic subacromial decompression offered no benefit after ten years of follow-up over placebo surgery or exercise in patients with symptoms consistent with subacromial pain syndrome for more than three months.
Signs and symptoms
Rotator cuff tendinopathy is often asymptomatic even when there is thinning or a full-thickness defect. Rotator cuff defects are common on post mortem and MRI studies in those without any history of shoulder pain or symptoms. Rotator cuff tendinopathy is associated with pain over the front and side of the shoulder that radiates towards the elbow. The pain may occur with shoulder movement above the horizontal position, shoulder flexion and abduction. Pain is often described as weakness. Actual muscle weakness does not correlate with symptoms of weakness. Symptom severity does not correlate with rotator cuff defect size and associated muscle quality.Risk factors
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 are also at greater risk. In a 2008 study the frequency of such tears increased from 13% in the youngest group to 20%, 31%, and 51% in the oldest group.
Some risk factors, such as 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 overuse 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 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 while 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 the natural ability to repair, increasing the risk for a 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
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.