What makes a rotator cuff tear symptomatic in humans?

What makes a rotator cuff tear symptomatic in humans?

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The majority of rotator cuff tears is asymptomatic {1}. What makes a rotator cuff tear symptomatic or asymptomatic in humans?


  • {1} Minagawa, Hiroshi, Nobuyuki Yamamoto, Hidekazu Abe, Masashi Fukuda, Nobutoshi Seki, Kazuma Kikuchi, Hiroaki Kijima, and Eiji Itoi. "Prevalence of symptomatic and asymptomatic rotator cuff tears in the general population: from mass-screening in one village." Journal of orthopaedics 10, no. 1 (2013): 8-12.,22 ;

    In conclusion, our survey of 664 residents in one village demonstrated that the prevalence of rotator cuff tear was 22.1% in the general population, which increased with age. Asymptomatic tear was twice as common as symptomatic tear.

    [… ]

    In this study, “asymptomatic” was defined as having neither pain nor any other symptoms related to the shoulder when the survey was conducted including the past history of shoulder pain, whereas “symptomatic” was defined as having pain or any other symptoms related to the shoulder when the survey was conducted.

    Caption: Prevalence of symptomatic and asymptomatic tears. Asymptomatic tear accounted for 50% of all tears in the 50s. However, in the 60s and over, the percentage of asymptomatic tear was significantly greater than that of symptomatic tear.

The underlying reason is difference in the rate of firing of torned and intact muscle in movement of shoulder joint.

Asymptomatic patients had minimal pain (<3 on the visual analog scale and no loss of active range of motion compared with the contralateral side); symptomatic patients had pain greater than 3 on the visual analog scale and decreased range of motion compared with the contralateral side (>10 degrees of motion loss). Electromyographic activity from 12 muscles and kinematic data were collected simultaneously during 10 functional tasks. Both symptomatic and asymptomatic cuff subjects demonstrated a trend toward increased muscle activation during all tasks compared with normal subjects. During the internal rotation tasks, asymptomatic patients had significantly greater (P<.05) subscapularis activity than symptomatic patients (65% maximal voluntary contraction [MVC] vs 42% MVC). During the carrying task, asymptomatic patients demonstrated significantly less (P<.03) upper trapezius muscle activation than symptomatic patients (16% MVC vs 50% MVC). During shoulder elevation tasks, symptomatic patients had significantly greater supraspinatus (52% MVC vs 28% MVC, P<.03), infraspinatus (32% MVC vs 16% MVC, P<.05), and upper trapezius (39% MVC vs 20% MVC, P<.04) muscle activation compared with asymptomatic patients. During heavy elevation (8 lb), asymptomatic patients showed a trend toward increased activation (P<.06) of the subscapularis compared with symptomatic patients (34% MVC vs 21% MVC). Differential shoulder muscle firing patterns in patients with rotator cuff pathology may play a role in the presence or absence of symptoms. Asymptomatic subjects demonstrated increased firing of the intact subscapularis, whereas symptomatic subjects continued to rely on torn rotator cuff tendons and periscapular muscle substitution, resulting in compromised function.

Source: Kelly, Bryan T., Riley J. Williams, Frank A. Cordasco, Sherry I. Backus, James C. Otis, Daniel E. Weiland, David W. Altchek, Edward V. Craig, Thomas L. Wickiewicz, and Russell F. Warren. "Differential patterns of muscle activation in patients with symptomatic and asymptomatic rotator cuff tears." Journal of shoulder and elbow surgery 14, no. 2 (2005): 165-171.

Rotator Cuff Injury and Repair

Anyone who has injured a shoulder’s rotator cuff has a deep appreciation for the role this group of muscles and tendons plays in a healthy lifestyle. A painful rotator cuff makes it difficult to reach up into a cabinet for something, or down to pick up a child, or around to swing a baseball bat.

Yale Medicine Orthopedics & Rehabilitation offers comprehensive and skilled care for rotator cuff injuries. Our surgeons provide nonoperative care, as well as tall of the latest surgeries, including arthroscopic and minimally invasive procedures, open procedures and revision surgery.

How do I treat the stiffness?

You should always follow the directions of your surgeon after surgery, since some tears need more time to heal than other tears. The best thing is to listen to your doctor as well as the physical therapist involved in your care. We tell our patients that ice is helpful for the pain, along with pain medicine of some sort, such as acetaminophen (e.g. Tylenol), anti-inflammatory medications (e.g. aspirin, ibuprofen, naproxen, etc.), pain relievers (non-narcotic or narcotic) and even prednisone by mouth (e.g. cortisone dose packs). You should take these medications only at the direction of your doctor. We usually recommend that during the first three months the emphasis in physical therapy and with your home program should be on regaining motion in your fingers, wrist, elbow and shoulder. We tell patients they have the rest of their lives to get strong, but during the first four months after rotator cuff surgery, the major goal should be largely to regain motion in the shoulder. Stiffness in the shoulder can be the cause of pain months after the surgical repair, so it is important that stiffness be addressed even months or years after the surgery.

Torn rotator cuff: Everything you need to know

A torn rotator cuff is a common injury that affects a person’s ability to lift and rotate their arm.

According to the American Academy of Orthopaedic Surgeons, an estimated 2 million people in the United States will visit a doctor for a rotator cuff problem each year.

The rotator cuff is four muscles connected by tendons to the humerus, or upper portion of the shoulder.

When a rotator cuff tear occurs, one or more of the tendons detaches from the humerus. The tear may be complete or partial and can cause significant pain and restrict movement.

Both surgical and nonsurgical treatments are available when a person tears their rotator cuff.

Rotator cuff injury causes tend to fall in one of two categories — an acute injury or chronic degeneration.

Acute injury

Share on Pinterest Injury or degeneration of the tendons can cause a torn rotator cuff.

A person can tear their rotator cuff performing a variety of activities. Examples of these types of injuries include:

  • trauma, such as breaking a collarbone or dislocating a shoulder
  • falling onto an outstretched arm
  • lifting something in a sudden, jerking motion
  • lifting something that is too heavy

These are just some of the common activities that can cause a rotator cuff tear.

Chronic degeneration

A person’s tendons naturally wear down as they age. This degeneration is especially true for a person’s dominant arm.

Some of the potential contributors to chronic degeneration include:

  • Affected blood supply: Blood supply to the tendons lessens with age, which increases the risk of tearing a rotator cuff. This means injuries are more common after 40 years of age.
  • Bone spurs: Bone spurs are overgrowths of bone that can occur from repetitive movements. A person may notice that the pain worsens when they lift their arm if the bone spur presses on the rotator cuff.
  • Repetitive movements: Athletes and people who work with their hands are prone to rotator cuff injuries. Examples of activities that increase the risk include baseball, rowing, and weightlifting. Common occupations where a person is prone to a rotator cuff tear include carpentry and decorating.

Rotator cuff tears may not immediately cause pain, although they can in acute injuries. Sometimes, a person may hear a distinct snapping sound with weakness in the upper arm afterward.

Other symptoms doctors associate with a rotator cuff tear include:

  • popping sensations when a person moves their arm
  • cracking sensations, known as crepitus, when moving the shoulder
  • pain in the shoulder even at rest
  • pain when lifting the arm or when throwing overhead
  • shoulder locking into place
  • weakness in the arm and hand

Sometimes, rotator cuff injury symptoms occur not only from the injury itself but also due to inflammation.

This inflammation is typically in the protective bursa sacs in the rotator cuff. Doctors call this condition bursitis.

A doctor will ask about a person’s symptoms, how the injury occurred, and if anything makes the pain better or worse.

They will also do a physical examination to determine a person’s range of motion and listen for any cracking or popping when they move their shoulder.

A doctor can also arrange imaging studies of the arm and shoulder, such as:

  • X-ray: This type of imaging will look for signs of bone calcifications, arthritis, or other injuries.
  • Magnetic resonance imaging (MRI): This method of imaging uses a magnetic field to generate images of soft tissue. A doctor can identify areas of inflammation and potential tearing.

Depending on the nature of the injury, a doctor may perform other tests to determine if the rotator cuff is torn or if symptoms are due to another problem.

The treatment for a rotator cuff repair often depends on the tear’s severity, and how much it is affecting the individual.

A doctor will usually recommend conservative methods over surgical treatment whenever possible.

Examples of conservative treatments for rotator cuff injuries include:

  • Rest: Resting the affected shoulder and wearing a sling for a few days following the injury can help reduce inflammation and pain. A doctor may also recommend avoiding certain activities to reduce strain on the shoulder.
  • Physical and occupational therapy: Therapy exercises to stretch and strengthen the muscles around the shoulder can help reduce the demands on the injured rotator cuff.
  • Over-the-counter medications: Medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) can help relieve pain. Examples of these include ibuprofen and naproxen sodium.
  • Injections: A doctor may recommend corticosteroid injections into the shoulder to reduce inflammation and improve mobility.

It is possible for a rotator cuff tear to worsen or persist over time, even with at-home treatments.

If the rotator cuff does not heal with conservative methods, a doctor may recommend surgical treatment. Surgery may also be necessary for a tear greater than 3 centimeters.

A doctor will discuss the likelihood of the repair being successful, and the range of motion a person can expect after the surgery.

A 2015 meta-analysis covered studies on rotator cuff surgery versus conservative treatment. The evidence from this investigation suggests that surgery is not necessarily more effective than conservative treatments.

The authors concluded that more research is necessary, although current evidence does not suggest surgery is a guaranteed success for rotator cuff tears.

The surgical approach to a rotator cuff tear depends upon the tear’s severity and position. Sometimes, a surgeon will treat it by reattaching the tendon to its original attachment point.

Another approach involves trimming the injured tendon or smoothing the affected area. A doctor can do this by inserting small instruments into the shoulder and using other special tools to manipulate and repair the tendon.

Other surgical approaches include an open repair where a surgeon makes a larger incision.

Associated Conditions

Sometimes, shoulder pain can come on for no apparent reason. Wear and tear of the rotator cuff and shoulder joint may occur due to repetitive stress and postural neglect. When this happens, different structures around your rotator cuff may become compromised.

If you have suffered an injury to your rotator cuff, you may experience pain or weakness when lifting your arm. Your rotator cuff injury may cause difficulty with basic functional activities like lifting, reaching, or sleeping.

Possible injuries and problems with these four rotator cuff muscles may include:

Any of these problems around your shoulder can cause limited motion and function.

But surprisingly, some people have rotator cuff tears that show up on magnetic resonance imaging (MRI) though they have no pain, loss of strength, or limited function. The presence of a rotator cuff tear does not necessarily mean you will experience problems with your shoulder.  

Risk Factors for Rotator Cuff Injuries

There are certain motions and activities that increase your likelihood of suffering a rotator cuff injury. These include:

  • Performing overhead tasks
  • Repetitive stress to your shoulder joint, as in throwing and racquet sports
  • Contact sports
  • Sitting with a rounded shoulder posture
  • Failing to maintain general physical fitness

Normal wear and tear of the rotator cuff, as well as aging, also increase the risk of injury.   Accidents, such as a car accident or fall, can also result in a rotator cuff issue.

Working to maintain healthy joints, avoiding overhead and repetitive strain on your shoulders, and maintaining proper posture can help you avoid painful shoulder injuries.

4. Discussion

The most important finding of this study was that the treatment of partial rotator cuff tears with PRP injections seems to lead to significantly better outcomes in terms of pain and shoulder function in long-term follow up, whereas, in short- and medium-term follow up, PRP injections seem to be superior only in terms of shoulder function.

Rotator cuff disorders are the most common cause of shoulder disability. However, management of rotator cuff problems remains controversial, mainly because of the remarkable variability of the clinical manifestations and insufficiency of information regarding the natural history of these disorders [28,29].

Resting, NSAIDs, physical therapies (therapeutic ultrasound, laser, tens, etc.) and training rotator cuff muscles with strengthening and stretching exercise programs are recommended for patients complaining of shoulder pain [30]. Recently, injection therapies (including steroids, PRP, prolotherapy and sodium hyaluronate) have been considered to treat those rotator cuff tendon problems. The indications are controversial and a complete agreement has not been reached so far by the various authors studying these methods [31,32]. Despite the advances in conservative treatment cases of tendinosis are still difficult to treat successfully in the long term [26]. Most of the studies did not include a detailed description of patient randomization methods thus, we could not effectively evaluate for patient selection bias. Using ROM as a surrogate outcome measure for functional assessment data should be viewed with caution, since the possible differences found could be due to inter- and intraoperator variability.

The use of corticosteroids should be carefully evaluated given the high risk of muscle weakness, tendon rupture and collagen collapse [33]. PRP is a method recently developed due to the discovery of growth factors released by platelets, which have been shown to be effective in tissue repair. Prolotherapy injection is a technique that has been previously used treating other orthopedic diseases the ease of application, the reduced cost and the reduction of the rehabilitation process make it advantageous [34].

This paper revealed that, with the aim of reducing pain, the effect of corticosteroid injection is stronger in the short and medium term compared to other injections although not statistically significant, whereas PRP provided better functional outcomes during the whole follow up period analyzed and more pain reduction in the long term ( Table 4 ). Therefore, for patients with partial rotator cuff tear, corticosteroid plays a role in the short term but not in long-term pain reduction. By contrast, PRP may yield better outcomes according to shoulder functionality and long-term pain reduction. Only one study compared PRP and prolotherapy over the long term as regards pain control, highlighting the absence of significant differences [26].

The short-term �icacy” of corticosteroids as found in this review is in agreement with previous evidence [8,9,35]. Several systematic reviews have found the effectiveness of corticosteroids in the treatment of shoulder disorders [36,37,38,39,40,41].

Several authors agree with the concept that repeated corticosteroids injections at short intervals are dangerous with regard to tendon atrophy and reduction of connective tissue quality [42,43]. Despite the efficacy of prolotherapy on rotator cuff lesions [8], tendinopathies and fasciopathies of the lower limbs [44] reported in different papers, only two studies included in this review analyzed this technique therefore more comparative trials need to be carried out to better evaluate this treatment.

The complications reported were described in only two of the studies analyzed [21,25]. Hong et Al. reported no serious complications other than transient diarrhea on day 3 after injection, facial flushing on days and dizziness due to vasovagal reaction during injection in the [21] Damjanov et al. noticed eight transient adverse events (AEs) in three patients within the corticosteroids treated group, listed as headache, arterial hypertension, facial erythema and facies lunata. No AEs were reported in the PRP group during the 24-week follow up period [25].

The remaining studies did not find or did not report any complications, although several studies in the literature have described tendon rupture events associated with the use of corticosteroids [45]. Because of the heterogeneity of the studies, a meta-analysis was not conducted. The available data does not allow to calculate the frequency and the optimal number of infiltrations to be carried out.

Strengths and Limitations

Despite the PRP group constant score being significantly higher in short and long term follow up, the difference with the corticosteroid group was below the MCID (minimal clinical importance difference). Therefore, our results should be taken with caution, as the PRP may not be the appropriate treatment for every partial tear. It may be possible that a clinical difference would present with a longer follow-up period.

An inter-reviewer agreement in assessing MINORS score of the studies included was not calculated, which is a limitation of the review process. The most relevant limitation of the present investigation is the low number of studies available on this topic. A further limitation is the difficulty to compare different outcomes, which was related to the differences in study design and in dose and medication used for the treatment. Moreover, there is heterogeneity in diagnosis criteria among different trials. Many of the trials used clinical diagnosis for rotator cuff tendinopathy without image confirmations and it may be very difficult to differentiate a partial rupture from a total one. However, the present systematic review is the first piece of work carried out with the aim to evaluate the role of conservative treatment for partial thickness rotator cuff tears.

3 Symptoms Suggesting A Rotator Cuff Tear

If you are over 30 years old, chances are greater than 30% at one time or another you have experienced some type of shoulder discomfort. All human beings can relate to whether it was a transient sting in the shoulder after a sudden tug or fall, or a lingering nagging ache that just does not seem to go away.

You don’t have to be an athlete to experience shoulder pain. Second to back pain, shoulder pain is the most common musculoskeletal problem seen by health care professionals in this country. More than 6 million patients seek medical care for shoulder pain in the U.S. each year. More than 30% of these are related to the rotator cuff, and approximately 1 in 7 of rotator cuff issues eventually undergo surgery.

This high prevalence of shoulder pain, and particularly, rotator cuff disease lies in the unique anatomy of our shoulder joints as being the most mobile joint in our body. This mobility gives us our ability to place our hands virtually anywhere in space, such as reaching for that grocery bag in the back seat of a car or screwing in that high ceiling light bulb. In exchange for this increased mobility comes with it inherent instability. 100% of shoulder stability rely on the rotator cuff muscles. There is no bony socket for structural support as in the hip joint. The 4 rotator cuff muscles emanate from the shoulder blade (scapula) and extend out toward the top of the arm bone (humerus) like a group of outcropping legs of an octopus. These are the 4 rotator cuff tendons. These tendons are supple to allow directional changes when the arm moves, however must be simultaneously stiffen up to keep the shoulder joint centered and aligned during arm motion and prevent dislocation. It is this delicate balance between flexibility and rigidity that is so taxing on the rotator cuff.

Rotator cuff disease present in various shades of gray. This can be construed as the fabric of your jeans where they go through varying degrees of wear and tear. These may range from a simple surface discoloration, to mild fraying, to small separation, all the way to a large gap. The actual tears may be either acute or acute-on-chronic or most commonly may develop as a result of a chronic degeneration process. In fact, an estimated 50% of healthy population have radiographic evidence of bilateral rotator cuff tears after age 66 years, although symptoms may vary. It is noted that statistically, almost all full thickness rotator cuff tears occur in individuals over 40 years of age. Full thickness rotator cuff tears in younger individuals are invariably associated with a catastrophic event that leaves no guess work whether the tendon is torn or not.

The 3 most common complaints by patients who have full thickness rotator cuff tears are : (1) Pain at night and unable to sleep on the affected side. (2) History of recurrent episodes of shoulder “tendinitis” or “bursitis”. These episodes of shoulder soreness may seem to have gone away after a period of rest, or use of anti inflammatory medication, or even a cortisone injection. But these episodes become more frequent and linger longer in spite of rest and medication. (3) Reproducible pain and weakness with arm elevations overhead or against resistance, particularly painful when the arm externally rotates such as when trying to put the arm into the sleeve of a jacket.

Treatments are varied. Not everyone with rotator cuff tears necessarily undergo surgery. Many factors come into the decision making process. Most importantly being how much does the shoulder bother you? How frequent, how severe, and under what circumstances? How much are you willing to live with the symptoms and how much are you willing to change your activity in exchange for less of symptoms? How is your health in general and are you willing to accept the potential risks and complications associated with surgery? Keeping in mind that there may be a need for repeat surgery in the event that the repair does not heal. What are your goals and expectations? Surgery is no panacea and treatment options can only be arrived after thorough discussions with your treating surgeon. Everyone is treated differently. Individual variations must be kept in mind.

In spite of technological advances and improved surgical techniques, unfortunately 10-90% of all rotator cuff repairs fail to heal after surgery. This has to do with the biology of healing. Broken bones reliably heal, because it is bone-to-bone healing. Torn muscles heal, because it is muscle-to-muscle healing when sewn together. Even in circumstances where tendons are torn in mid substance such as sewing back the torn achilles tendon, tendon-to-tendon, they heal. But in the case of the rotator cuff tendon, where the tendon is detached from the bone, when repaired together, it is relying on tendon-to-bone healing. Tendon-to-bone healing is not very reliable because tendon and bone are two dissimilar substances. Just like oil and vinegar, they are difficult to mix. However, remarkably, 60-85% of those with rotator cuff tears seem to have successful outcomes after non-operative management. In fact, as an entire population, over 95% of those individuals with full thickness rotator cuff tears over age 65 never wind up having surgery.

Force Couples

A force acting on a body has two effects, one to move it and two to rotate it. However, a body may rotate without moving. I.e. a force can cause only rotation with out translation. A force couple is a system that exerts a resultant movement, but no resultant force. Two equal and opposite forces exert a purely rotation force. In the shoulder the body is the humeral head and the equal but opposite forces are the rotator cuff muscles.

In a force couple, force generated by one muscle (the primary agonist) requires the activation of an antagonistic muscle so that a dislocating force does not result (Nordin & Frankel, 2001).

The rotator cuff muscles act as a force couple with each other and the deltoid. The rotator cuff muscles work together to contain the glenohumeral joint, which is an inherently unstable joint. The progression of a rotator cuff tear or dysfunction leads to superiorsubluxation of the humeral head. This leads to dysfunction of the shoulder.

The rotator cuff stabilises the glenohumeral joint through force couples in both the coronal and transverse planes.

Coronal Force Couple

Deltoid and supraspinatus both contribute to abduction equally.
As the arm is abducted the resultant joint reaction force is directed towards the Glenoid. This 'compresses' the humeral head against the Glenoid and improves the stability of the joint when the arm is abducted and overhead. [ Parsons et al. J Orthop Res. 2002 ]

Transverse Plane Force Couple

Throughout the range of motion the compressive resultant joint reaction force in the transverse plane contributes to joint stability. This is the predominant mechanism resisting superiorhumeral head displacement with cuff tears. As long as the force couple between subscapularis and Infraspinatus remains balanced the joint remains centred. [Parsons et al. J Orthop Res. 2002]

What makes a rotator cuff tear symptomatic in humans? - Biology

OBJECTIVE. The purpose of this article is to review the biomechanical properties of the rotator cuff and glenohumeral joint and the pathophysiology, imaging characteristics, and treatment options of rotator cuff tear arthropathy (RCTA).

CONCLUSION. Although multiple pathways have been proposed as causes of RCTA, the exact cause remains unclear. Increasing knowledge about the clinical diagnosis, imaging features, and indicators of severity improves recognition and treatment of this pathologic condition.

The shoulder has the most mobility but the least intrinsic stability of all joints in the human body [1]. A complex association of static and dynamic stabilizers balances the joint's mobility with its functional stability. The rotator cuff tendons play a crucial role in maintaining this dynamic stability in the naturally unstable glenohumeral joint [2, 3]. The loss of this important stabilizer can lead to a complex pattern of joint degeneration referred to as rotator cuff tear arthropathy (RCTA). Understanding the role of the rotator cuff in maintaining the balance between mobility and stability leads to an appreciation of the progressive findings seen in RCTA and the treatment options that are available if arthropathy progresses to joint failure.

In 1977, Charles Neer and his colleagues invented the term “cuff tear arthropathy” and eventually provided the first detailed description of RCTA in 1983 [4]. RCTA has three major characteristics: first, massive rotator cuff tear ( Fig. 1A ) second, degenerative changes (i.e., glenoid erosion, loss of articular cartilage, osteoporosis of the humeral head, and eventually humeral head collapse) ( Figs. 1B and 1C ) and third, superior migration of the humerus resulting in “femoralization” of the humeral head ( Fig. 2A ) and “acetabularization” of the coracoacromial arch [5] ( Fig. 2B ).

Fig. 1A —MRI of rotator cuff tear arthropathy.

A, Coronal proton density–weighted MR image of 73-year-old woman shows massive rotator cuff tear.

Fig. 1B —MRI of rotator cuff tear arthropathy.

B, Coronal proton density–weighted MR image of 69-year-old woman shows chronic superior migration of humeral head (arrow) resulting in full-thickness chondral loss, osteophyte formation, and subchondral cystic changes over superior humeral head and superior glenoid.

Fig. 1C —MRI of rotator cuff tear arthropathy.

C, T2-weighted fat-suppressed MR image of right shoulder of 58-year-old woman shows chronic superior migration of humeral head resulting in degeneration and maceration of superior labrum (arrowhead).

Fig. 2A —Radiography of rotator cuff tear arthropathy.

A, Frontal radiograph of right shoulder of 73-year-old woman shows femoralization of humeral head and erosion of greater tuberosity (arrowhead).

Fig. 2B —Radiography of rotator cuff tear arthropathy.

B, Frontal radiograph of left shoulder of 87-year-old man shows acetabularization of coracoacromial arch— that is, reshaping of coracoacromial arch to create socket for superior aspect of humerus (arrow).

Understanding the imaging findings and stages of RCTA is important in the preoperative evaluation of the patient with a symptomatic massive rotator cuff tear because this information can be used to determine the proper surgical treatment of end-stage arthropathy and to provide patients with realistic expectations about the postoperative outcome. The objectives of this article are to review the biomechanical properties of the rotator cuff and glenohumeral joint and their relationship to the pathophysiology of RCTA. We will discuss the various imaging modalities and classification systems for the diagnosis of RCTA and will review the current management options for treatment.

The glenohumeral joint lacks intrinsic osseous constraints, which allows a high degree of mobility but simultaneously creates inherent instability. This instability is compensated for by many static stabilizers, such as the labrum, joint capsule, and glenohumeral ligaments. The dynamic stabilizers of the rotator cuff—which consist of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles—are crucial. These muscles provide stability through a mechanism termed “concavity compression” [6–8] ( Fig. 3 ).

Fig. 3 —Drawing shows concavity-compression mechanism (triple-headed arrow) of rotator cuff: Rotator cuff muscles (single-headed arrows) provide joint stability and center humeral head on glenoid cavity. (Drawing by Murakami AM)

The forces acting on the shoulder can be divided into three components: a stabilizing compressive force, a destabilizing translational superior-inferior force, and an anterior-posterior force. Joint stability is simply a balanced ratio between the translational forces in any direction and the compression forces [9–11]. For instance, the combined force of the subscapularis muscle anteriorly and the infraspinatus and teres minor muscles posteriorly provide antagonistic forces that compress the humeral head onto the glenoid bone [3, 12]. This stability also depends on the effective glenoid arc and the area of the glenoid's articular surface available for humeral head compression [13]. Also important is the interplay between the deltoid muscle and the rotator cuff. The rotator cuff provides a net inferiorly directed and compressive force, whereas the strong deltoid muscle provides a superiorly directed force these forces result in a net force balance or force coupling of the glenohumeral joint [14] ( Fig. 4A ).

Fig. 4A —Rotator cuff. (Drawings by Murakami AM)

A, Rotator cuff biomechanics. Drawing shows that net inferior and compressive force vector (double-headed arrow) of rotator cuff is balanced by net superiorly directed force vector of deltoid muscle (single-headed arrow).

Fig. 4B —Rotator cuff. (Drawings by Murakami AM)

B, Rotator cuff insufficiency. Drawing shows superior migration of humeral head and degenerative changes of glenohumeral joint (arrow) that are suggestive of rotator cuff insufficiency.

There is no general agreement regarding the definition of a “massive” rotator cuff tear, although its prevalence has been reported in the literature to range from 10% to 40% of all rotator cuff tears [15–17]. Both functional and anatomic characteristics have been used to classify massive rotator cuff tears, but each type of characteristics has some disadvantages. Cofield et al. [18] defined a massive rotator cuff tear as a cuff tear with a diameter of 5 cm or larger, whereas Zumstein et al. [19] defined it as complete detachment of two or more tendons. Other investigators have proposed classification systems based on the area of the defect or on indexes of tear dimensions [20].

Despite the different criteria used to define a massive rotator cuff tear, the result of a massive rotator cuff tear is the destabilization of the glenohumeral joint and the attritional destruction of the primary static stabilizers, leading to chondral wear and subsequent osteoarthritis [21]. It is noteworthy that massive rotator cuff tears, although technically challenging to repair, are not necessarily irreparable [22]. Signs of irreparability include static superior migration of the humeral head, a narrowed or absent acromiohumeral interval (AHI), and fatty infiltration affecting 50% or more of the rotator cuff muscles [16, 17, 23, 24].

The exact cause of RCTA is unknown, although numerous pathomechanical concepts have been hypothesized for its development.

An association between RCTA and the presence of calcium phosphate crystals in synovial fluid and tissue was proposed by Halverson et al. [25]. They postulated that the calcium phosphate–containing crystals in synovial tissue induce an immunologic cascade that leads to the release of proteolytic enzymes and that these proteolytic enzymes cause the rapid degradation of the cartilage matrix components and the destruction of periarticular and articular structures [26].

Neer et al. [21] hypothesized that massive rotator cuff tears lead to the degeneration of the shoulder joint through two mechanisms: a mechanical pathway and a nutritional pathway. This concept is based on clinical observations and pathologic observations made at surgery and on review of histologic samples.

Mechanical factors—The mechanical factors associated with massive rotator cuff tears lead to unbalanced muscle forces. These factors are anteroposterior instability of the humeral head, resulting from massive cuff tears and rupture or dislocation of the long head of the biceps tendon, which leads to superior migration of the humeral head and acromial impingement. Shoulder joint wear occurs as a result of repetitive trauma from the altered biomechanics associated with the loss of primary and secondary stabilizers. The wear on the glenoid bone is often eccentric, involving the anterior-superior margin. This wear leads to an accelerated process of further cuff destruction and arthropathy ( Fig. 4B ).

Nutritional factors—The nutritional factors associated with massive full-thickness tears are related to the loss of motion and periarticular damage due to disruption of the normal joint milieu. The loss of fluid pressure and the accompanying reduction in the quality of the chemical content of the synovial fluid lead to cartilage and bone atrophy. Recurrent bloody effusions and the loss of glycosaminoglycan content of the cartilage further accelerate the destruction of both bone and soft tissue [27].

The deltoid and rotator cuff muscles work cooperatively to preserve a balanced force couple for the glenohumeral joint in both the coronal and transverse planes. The muscles inferior to the humeral head equator maintain a balanced coronal force, whereas the subscapularis and infraspinatus–teres minor complex balance each other in the transverse plane. In this capacity, the rotator cuff muscles function as primary dynamic stabilizers to maintain a concentric reduction during rotation of the humeral head on the glenoid bone [28–31]. A massive rotator cuff tear can disrupt this force couple, as shown fluoroscopically by Burkhart et al. [14] in comparisons of the kinematic patterns of massive rotator cuff tears. As a result, the uncoupled or unopposed deltoid muscle leads to superior migration of the humeral head, which in turn results in the distinctive degenerative wear pattern on the acromion and coracoid process. Additionally, the uncoupling leads to instability and reduced motion, which lead to chondral loss.

Fatty degeneration of the rotator cuff muscles, which occurs after a rotator cuff tear, is characterized by atrophy of the muscle fibers, fibrosis, and fatty accumulation within and around the muscles [32, 33]. It is frequently associated with an aging-related reduction of the regenerative potential of the rotator cuff tendons [34]. Studies have shown that low-grade preoperative fatty degeneration may predict a better clinical outcome [32, 33], whereas high-grade infiltration is associated with a worse clinical outcome [35, 36]. A delayed diagnosis of a rotator cuff tear also worsens the prognosis because both the tendon and muscle belly undergo atrophy and degeneration [37]. Fatty infiltration and muscle atrophy have also been shown to not improve after successful structural repair of the rotator cuff, and their presence is associated with poor functional results [32, 38–40]. The risk of irreversible fatty infiltration of the rotator cuff muscles may limit future treatment options and must be considered when counseling patients. This event has a negative influence on both functional and radiographic outcomes [41].

A few classification systems based on radiography have been developed to define the bone changes that occur in RCTA. Although the characteristics of these systems overlap, each system focuses on a different set of findings associated with the disorder. These systems include the Seebauer system [27] and the Hamada system [42].

The Seebauer classification system separates RCTA into four distinct types: IA, IB, IIA, and IIB [27]. Each type is characterized by a massive rotator cuff tear, a distinctive level of joint instability, humeral head translation, and articular surface erosion [27]. This classification system is a biomechanical description of RCTA, in which each type is distinguished on the basis of the degree of superior migration of the humeral head from the center of rotation and the amount of instability [27]. The extent of decentralization seen on radiographs depends on the size of the rotator cuff tear, the integrity of the coracoacromial arch, and the degree and direction of glenoid bone erosion [27] ( Fig. 5 ).

Fig. 5A —Radiographs show examples of types of rotator cuff tear arthropathy (RCTA) according to Seebauer classification system [27].

A, 58-year-old man with type IA RCTA. Type IA is characterized as centered and stable. Imaging findings are intact anterior restraints, minimal superior migration, femoralization, and acetabularization.

Fig. 5B —Radiographs show examples of types of rotator cuff tear arthropathy (RCTA) according to Seebauer classification system [27].

B, 74-year-old woman with type IB RCTA. Type IB is characterized as centered and medialized. Imaging findings are intact anterior restraints, minimal superior migration, and medial erosion of glenoid bone.

Fig. 5C —Radiographs show examples of types of rotator cuff tear arthropathy (RCTA) according to Seebauer classification system [27].

C, 87-year-old man with type IIA RCTA. Type IIA is characterized as decentered, limited, and stable. Imaging findings are compromised anterior restraints, superior translation, minimal stabilization by coracoacromial arch, and superior and medial erosions of glenoid bone.

Fig. 5D —Radiographs show examples of types of rotator cuff tear arthropathy (RCTA) according to Seebauer classification system [27].

D, 68-year-old man with type IIB RCTA. Type IIB is characterized as decentered and unstable. Imaging findings are incompetent anterior structures, anterior-superior escape, and no stabilization by coracoacromial arch.

The Hamada classification system describes structural changes within the coracoacromial arch and changes in the acromiohumeral interval (AHI) on anteroposterior radiographs as the bases for classification [43]. This system divides massive rotator cuff tears into five radiographic stages, with consecutive stages indicating disease progression [42]. Table 1 shows the characteristics of each of the stages in this system.

The multiplanar imaging capabilities of MRI combined with its excellent soft-tissue contrast make it ideally suited for imaging the rotator cuff. Although a massive rotator cuff tear can often be diagnosed on the basis of physical examination and advanced radiographic findings as detailed earlier, MRI can be used to evaluate the integrity of the cuff overall or to determine whether an existing tear is repairable when other findings are ambiguous. Additionally, MRI can assist in the characterization of chondral loss that can be typical of RCTA.

The primary use of CT in patients with advanced osteoarthritis of the glenohumeral joint has been in the assessment of the glenoid bone. In particular, advanced osteoarthritis can be associated with posterior glenoid bone loss, which can inevitably lead to posterior subluxation of the humeral head. These findings are associated with a poor clinical outcome after total shoulder arthroplasty (TSA) [44]. Accurate assessment of the glenoid bone stock is also important in surgical planning because a small volume of bone may require bone grafting to accommodate the glenoid prosthesis [45]. CT has been shown to be more effective than radiography in this assessment and in the measurement of glenoid version [46]. Glenoid version is defined by Friedman et al. [47] as the angle between a line drawn from the medial border of the scapula to the center of the glenoid bone and the line perpendicular to the face of the glenoid bone on the axial 2D CT slice at or just below the tip of the coracoid process.

Both CT and MRI can be used to assess the degree of fatty infiltration according to the classification system proposed by Goutallier et al. [33]. They first described a classification system based on the presence of fatty streaks within the muscle belly on CT, but the grading criteria have since been applied to MRI [37, 48]. The classification system that Goutallier et al. [33] described in their original article in 1994 is composed of five stages of fatty infiltration ( Fig. 6 and Table 2).

Fig. 6A —Stages of fatty infiltration of rotator cuff muscles according to classification system proposed by Goutallier et al. [33].

A, MR image of 33-year-old woman shows stage 0 fatty infiltration.

Fig. 6B —Stages of fatty infiltration of rotator cuff muscles according to classification system proposed by Goutallier et al. [33].

B, MR image of 74-year-old man shows stage 1 fatty infiltration.

Fig. 6C —Stages of fatty infiltration of rotator cuff muscles according to classification system proposed by Goutallier et al. [33].

C, MR image of 58-year-old woman shows stage 2 fatty infiltration.

Fig. 6D —Stages of fatty infiltration of rotator cuff muscles according to classification system proposed by Goutallier et al. [33].

D, MR image of 73-year-old woman shows stage 3 fatty infiltration.

Fig. 6E —Stages of fatty infiltration of rotator cuff muscles according to classification system proposed by Goutallier et al. [33].

E, MR image of 58-year-old man shows stage 4 fatty infiltration.

Sonography is an alternative modality for evaluating the rotator cuff that is capable of providing images with high image contrast but without the use of ionizing radiation. The diagnostic accuracy of shoulder sonography for rotator cuff tears can reach as high as 91% and 100% for partial- and full-thickness tears, respectively [49–51]. Although the accuracy of sonography hinges on the skill and experience of the operator performing the examination [52], sonography is a suitable alternative modality in patients who are not able to undergo MRI because it is contraindicated or cannot be tolerated.

Patients presenting with RCTA present with pain, disability, or both. Numerous treatment options are available, and the treatment of choice varies according to the patient's circumstances, surgeon's preferences, and resources.

The initial management of RCTA should begin with conservative measures including activity modification, oral analgesics including nonsteroidal antiinflammatory drugs or cyclooxygenase inhibitors, physical therapy, fluid aspiration, and intraarticular injections of corticosteroid and hyaluronans. Aspiration and corticosteroid administration may be a useful adjunct to physical therapy for patients who are unable or unwilling to undergo surgical intervention. Intraarticular corticosteroid injections may be useful at first, but multiple injections are not recommended because of decreasing utility and the possibility of increasing the risk of infection [53]. Although the initial management of RCTA should begin with conservative measures, surgical intervention is often required.

Total shoulder arthroplasty—TSA is most commonly performed for the treatment of advanced degenerative osteoarthritis in patients older than 60 years [54]. Other indications include inflammatory arthritis, humeral head avascular necrosis with secondary glenohumeral arthritis, postinfectious arthritis, and Charcot arthropathy [54, 55].

Unconstrained TSA prostheses were used by Neer et al. [4, 21] to treat 26 shoulders with RCTA and yielded poor functional outcomes. The poor outcomes were thought to be related to the superior migration of the humeral head seen with a defective rotator cuff, which resulted in eccentric loading of the superior aspect of the glenoid component. Over time, this eccentric loading resulted in loosening of the glenoid component, a complication that Franklin et al. [56] termed the “rocking horse glenoid.”

Constrained and semiconstrained TSA prostheses were used with the hope of preventing superior humeral head migration and thus the eccentric loading of the superior aspect of the glenoid component. Nevertheless, these prostheses still caused stresses at the superior interface of the glenoid component and therefore were also associated with high rates of glenoid component loosening [57, 58].

Humeral hemiarthroplasty—Humeral hemiarthroplasty is now a current treatment option for patients with symptomatic RCTA and modest functional goals [53, 59–62]. The benefits of humeral hemiarthroplasty are a shorter and technically easier surgery: Repair of the rotator cuff is easier because of less humeral lateralization [58], and the lack of a glenoid component eliminates the potential complication of component loosening. Humeral hemiarthroplasty also avoids the problem of the rocking horse glenoid. The results from several studies have shown no pain or mild pain in 47–86% of shoulders with glenohumeral arthritis and a deficient rotator cuff treated with humeral hemiarthroplasty [53, 59–61]. Active forward elevation of the glenohumeral joint was also found to increase by an average of 17–50° after humeral hemiarthroplasty [53, 59–61]. Based on the “limited-goals” criterion proposed by Neer et al. [4, 21], between 63% and 86% of humeral hemiarthroplasties were considered to have successful outcomes [53, 59, 61]. However, studies have shown that a significant number of patients are left with painful and unsatisfactory shoulders after humeral hemiarthroplasty, even though this surgical option helped many patients and was preferable to TSA [53, 61, 63].

Reverse total shoulder arthroplasty— RCTA is currently the primary indication for reverse TSA, as this group has reported predictable outcomes [64]. The ideal candidate for reverse TSA is an older patient with decreased functional demand, a preoperative active forward elevation of the glenohumeral joint of less than 90°, and an intact deltoid muscle. As surgeons have gained more experience with reverse TSA, the indications have been expanded to include revision arthroplasty, inflammatory arthropathy with a massive rotator cuff tear, painful and irreparable rotator cuff tear, proximal humeral nonunion or malunion, acute fractures, tumor, and chronic pseudoparalysis without arthritis [65–75].

A reverse TSA is essentially a reversal of the normal shoulder ball-and-socket anatomy. In this design, the concave component replaces the humeral head, and the convex component is fixed to the glenoid bone, which results in a “humerosocket” and a “glenosphere.” It is composed of three main components: the baseplate (metaglene), the glenosphere, and the humeral socket. The baseplate is a metal-backed plate that directly contacts the glenoid bone ( Fig. 7 ).

Fig. 7A —Reverse total shoulder arthroplasty (TSA).

A, Drawing shows anatomy after reverse TSA: “Ball” is at glenoid, and “socket” is on humeral head. Axis is moved medially and distally to allow control by deltoid muscle. Arrow shows restored center of rotation. (Drawing by Murakami AM)

Fig. 7B —Reverse total shoulder arthroplasty (TSA).

B, Radiograph of 74-year-old woman who underwent reverse TSA of right shoulder shows prosthesis.

Fig. 7C —Reverse total shoulder arthroplasty (TSA).

C, Photograph shows reverse TSA prosthesis.

This design results in a semiconstrained prosthesis that stabilizes the glenohumeral center of rotation like a functioning rotator cuff [76]. This design avoids the superior migration of the humerus on the glenoid bone, thereby restoring the deltoid muscle's anatomic resting length. The deltoid muscle now can compensate for the rotator cuff deficiency. By replacing both sides of the joint, reverse TSA offers more reliable pain relief than humeral hemiarthroplasty [59]. Multiple series of patients with RCTA that was treated using reverse TSA have shown substantial improvements in Constant-Murley scores, an average active forward elevation of the glenohumeral joint of greater than 110°, and good long-term joint stability [77–81]. Furthermore, a faster recovery may be achieved because the rotator cuff does not need to be protected during the early postoperative period [82]. Several clinical studies have also reported noticeable improvements in activity and quality of life after a successful reverse TSA [65, 78, 81, 83, 84]. Although abundant long-term data are not available, short- to intermediate-term outcome studies suggest that survivorship of the reverse TSA is comparable with humeral hemiarthroplasty and TSA [78, 81, 85–90].

Arthrodesis—Another surgical option is glenohumeral arthrodesis, which has the goal of relieving pain by eliminating motion. The most noticeable disadvantage of this procedure is the total loss of glenohumeral joint motion. Additionally, the compensatory scapulothoracic motion may expose the acromioclavicular joint to excessive motion and result in further pain [91, 92]. Despite these drawbacks, some patients may benefit from glenohumeral arthrodesis. Patients with multiple failed previous operations, a history of infection, or a deficient anterior deltoid muscle may have the best outcomes with glenohumeral arthrodesis [93].

Despite favorable short- and medium-term clinical results, the overall complication rate of reverse TSA is high, ranging between 19% and 68% depending on what is considered to be a complication [94]. Wall et al. [79] reviewed the results of reverse TSA according to cause and reported a 19% complication rate in 186 patients, with the most common complications being dislocation (7.5%) ( Fig. 8A ) and infection (4%). Glenoid fractures, humeral fractures, pain, radial nerve palsy, and loosening of the glenosphere or baseplate were among the least commonly reported complications. It is important to understand that the risk of complications in the revision surgeries was more than double that observed with primary surgeries (37% and 13%, respectively) [79]. Instability is one of the other complications that may be related to undertensioning of the deltoid muscle, deltoid insufficiency or detachment, or medial impingement of the humeral component on the scapular neck [79]. Overtensioning of the deltoid muscle, however, can lead to fracture of the acromion, especially in elderly patients with osteoporosis [95] ( Fig. 8B ). Given the dead space surrounding the prosthesis, there is a substantial risk of postoperative hematoma formation and deep infection [78].

Fig. 8A —Complications of reverse total shoulder arthroplasty (TSA): dislocation and stress fracture.

A, Frontal radiograph of left shoulder of 69-year-old woman shows dislocation of components of reverse TSA prosthesis.

Fig. 8B —Complications of reverse total shoulder arthroplasty (TSA): dislocation and stress fracture.

B, Frontal radiograph of left shoulder of 73-year-old man shows acromial stress fracture (arrowhead) due to reverse TSA prosthesis.

Another common complication is scapular notching, which is due to the impingement of the medial aspect of the humeral cup on the scapular neck during adduction [96–100]. The incidence of scapular notching has been reported to be as high as 96% [78]. A classification system proposed by Sirveaux et al. [43] in 2004 to grade scapular notching is illustrated in Figure 9 . In grade 1 of this classification, notching involves only scapular bone. Grade 2 notching contacts the inferior screw of the baseplate. Grade 3 notching extends to the superior aspect of the inferior screw of the baseplate, and grade 4 notching extends past the superior aspect of the inferior screw of the baseplate to include the area under the baseplate.

Fig. 9A —Complication of reverse total shoulder arthroplasty (TSA): scapular notching.

A, Drawing shows Nerot-Sirveaux grading system (grades 1–4) for characterizing postoperative scapular notching after reverse TSA. (Drawing by Murakami AM)

Fig. 9B —Complication of reverse total shoulder arthroplasty (TSA): scapular notching.

B, Radiograph of left shoulder of 69-year-old woman who underwent reverse TSA shows grade 4 scapular notching.

The clinical relevance of scapular notching is controversial. In some studies, significant scapular notching was associated with worse clinical outcomes and premature baseplate failure [66, 100]. Both the prevalence and severity of scapular notching are noted to increase over time [98]. Other studies have found no relation between notching and a lower Constant-Murley score, decreased range of motion, pain, or glenoid component loosening [98]. The incidence of scapular notching has been shown to depend on several factors, including the position or offset of the glenosphere. For example, the use of laterally offset glenospheres in different styles of prostheses has reduced the incidence of scapular notching to between 0% and 13% [81, 94].

RCTA is an uncommon and challenging to treat condition. Increased knowledge about the clinical diagnosis, imaging features, and imaging and clinical indicators of severity improves recognition of this pathologic condition. Multiple pathways have been proposed as the cause of RCTA, but the exact cause remains unclear. The initial management of RCTA should begin with conservative measures, but surgical intervention is often required. The current surgical treatments of RCTA are TSA, humeral hemiarthroplasty, and reverse TSA, with reverse TSA being the most recent advancement. In patients with advanced RCTA, painful pseudoparalysis, or both, reverse TSA can provide predictable pain relief and return of function but is associated with a relatively high risk of complications. The significant complication rate underscores the importance of strict patient selection and careful operative technique and the need for design modifications to the existing arthroplasty prostheses.

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  1. Nale

    This is evident, you have not been wrong

  2. Damario

    It is already nothing less than an exception

  3. Thorndyke

    I think you are wrong. I can prove it.

  4. Bourkan

    You have an inquisitive mind :)

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