Written by Gerard Malanga, MD, Coauthor: Jay E. Bowen, DO and Christopher J Visco, MD
Rotator cuff injuries are a common cause of shoulder pain in people of all age groups. They represent a spectrum of disease, ranging from acute reversible tendinitis to massive tears involving the supraspinatus, infraspinatus, and subscapularis. Diagnosis is usually made through detailed history, physical examination, and often, imaging studies. [1, 2, 3, 4, 5]
A normal rotator cuff and rotator cuff tear are shown below.
Rotator cuff, normal anatomy.
Rotator cuff tear, anterior view.
Often, younger individuals with rotator cuff injuries relate a history of repetitive overhead activities involving the rotator cuff or, less commonly, a history of trauma preceding clinical onset of symptoms. In contrast, older individuals usually present with a gradual onset of shoulder pain and, ultimately, after radiographic testing is shown to have significant partial or full rotator cuff tears without a clear history of predisposing trauma. Nonoperative or conservative treatment is usually sufficient to heal the problem in the vast majority of individuals, with a few exceptions that are discussed. [1, 2, 3, 4, 5]
The frequency of full-thickness rotator cuff tears ranges from 5-40%, with an increasing incidence of cuff pathology in advanced age. Cadaveric studies by Bigliani et al found that 39% of individuals older than 60 years had full-thickness rotator cuff tears with an even higher incidence of partial tears. 
Normal shoulder motion
The shoulder complex is comprised of several joints, including the sternoclavicular joint, acromioclavicular joint, glenohumeral (GH) joint, and scapulothoracic (ST) joint or pseudoarticulation. These articulations work together to carry out normal shoulder motion. The majority of motion occurs at the GH and ST joints. A rhythm between these 2 areas of motion has been described. [1, 3, 7, 8, 9, 10, 11, 12]
The GH–to–ST motion ratio of total shoulder motion is 2:1 (ie, 180° of abduction, consisting of 120° of GH motion and 60° of ST motion). The 2:1 ratio is an average over the entire arc of motion. This ratio changes through the arc of motion (ie, the 2:1 ratio is not constant throughout the entire range of motion [ROM]). In the initial portion of abduction, GH motion predominates and the ratio is 4:1 (GH:ST). As the shoulder moves above 90° of abduction, this ratio becomes 1:1° GH to 1° ST motion.
The importance of the scapula in normal shoulder motion cannot be overstated. The scapula, with the glenoid as its contact point, forms the platform for humeral head articulation and motion. A stable platform is essential for normal shoulder biomechanics in everyday activities and is crucial for high-demand activities (eg, overhead sports or work). 
The scapula must glide along the chest wall as it protracts and retracts during normal shoulder movements. Scapular winging results in glenoid antetilting, which results in functional elevation of the humeral head and impingement of the rotator cuff. In addition, without scapular motion, the origin and insertion of the deltoid approximate each other, resulting in a decreased optimal length-tension relationship and a decrease in force as the shoulder abducts. Normal scapular motion allows the deltoid to maintain its length-tension relationship and generate adequate force.
Stabilizers of the shoulder
The shoulder is considered a ball-in-socket joint, although the glenoid fossa is flat. In addition, the surface area of the glenoid is much smaller than that of the contacting humeral head (25-30%). The cartilaginous labrum provides much of the socket function and increases the surface area of contact for the humeral head.
Together, these components provide a great amount of shoulder mobility with limited stability. Shoulder stabilizers can be grossly categorized as static or dynamic. Dynamic stabilizers require an intact neuromuscular system to function, whereas static stabilizers help maintain congruity.
The static stabilizers have been studied well in cadaver specimens to understand their stabilizing effects. Static stabilizers continue to function in the setting of neurologic or intrinsic muscle pathology in conditions such as hemiplegia, spinal cord injury, brachial plexus injury, suprascapular nerve injury, and myopathies. This is not true for the dynamic stabilizers (eg, rotator cuff muscles). With neuromuscular injury or intrinsic muscle damage, the dynamic stabilizers lose their ability to exert dynamic motor control of the humeral head, ultimately eading to GH laxity and shoulder pain.
Static stabilizers include the bony structures, labrum, GH ligaments, and joint capsule. Unlike the hip joint, the bony articulation of the shoulder offers little stability. This is due to the limited contact area of the glenoid with the humeral head, flattened architecture, and retroverted positioning. The labrum is a fibrous structure that attaches to the glenoid to increase the contact area and deepen the socket of the glenoid up to 50%, forming a concave surface. Three GH ligaments exist, as follows: superior, middle, and inferior. The inferior GH ligament is the most important for shoulder stability and has 3 components, anterior, inferior, and posterior, therefore, it is more appropriately referred to as the inferior GH complex.
Dynamic stabilizers  include the rotator and scapular stabilizers (ie, teres major, rhomboids, serratus anterior, trapezius, levator scapula). The rotator cuff is composed of 4 muscles: the supraspinatus, infraspinatus, subscapularis, and teres minor. The supraspinatus is the principal supporting and kinetic muscle of the shoulder. The primary function of the rotator cuff muscles is to stabilize the GH joint so that the larger shoulder movers (eg, deltoid, latissimus dorsi) can carry out their function without significant motion of the humeral head on the glenoid. Increased movement results in shearing forces across the joint (to the labrum, in particular) and may result in humeral head migration and impingement upon the rotator cuff muscles and tendons.
The rotator cuff muscles are associated and assist with some shoulder motion; however, their main function is to provide stability to the joint by compressing the humeral head on the glenoid. The supraspinatus assists in shoulder abduction by maintaining the humeral head centered on the glenoid, with the middle deltoid acting as the primary mover. These muscles act as force couples, because they work synergistically to carry out a particular movement.
Electromyography (EMG) studies have demonstrated a high degree of supraspinatus activity during the initial 30° of abduction. This has been misinterpreted to imply that the supraspinatus initiates shoulder abduction and acts to abduct the shoulder in the first 30°. In actuality, the supraspinatus fires to stabilize the GH joint as the deltoid abducts the arm. [15, 16, 17, 18, 19]
Increased EMG activity in the supraspinatus during the initial 30° is a reflection of increased firing requirements of this muscle to stabilize the GH joint as the deltoid is activated. The infraspinatus and teres minor muscles assist in external rotation of the shoulder and also provide an inferior pull upon the humeral head, assisting in its centering during overhead activity. The subscapularis muscle participates in this centering but also acts with the pectoralis muscles and latissimus dorsi as an internal rotator of the shoulder, serving as the main internal rotators of the shoulder.
Weakness or insufficiency of the rotator cuff muscles results in increasing demands on the static stabilizers. If these demands are long term or recurrent, static stabilizers may begin to fail. This can result in stretching or attenuation of the capsule, which results in even greater shoulder laxity and greater demands on the already weak rotator cuff muscles. Humeral head migration may occur with capsule laxity and result in rotator cuff impingement and pain. Pain may inhibit rotator cuff muscle firing, leading to disuse and further weakening of the dynamic stabilizers with greater demands placed on the static stabilizers.
Increased humeral head translation can also lead to shearing and injury to the glenoid labrum. Rotator cuff impingement, tendinitis, and labral pathology are commonly encountered injury patterns in athletes and workers who perform overhead motions. Focusing solely on the static stabilizers in treatment neglects the dynamic structures that probably initiate and perpetuate the cycle.
A similar type of motion is involved in a number of overhead sports activities (eg, serving in tennis, spiking in volleyball, throwing a football or baseball). The baseball throwing motion has been studied in detail and can be divided into 5 stages.
- Stage 1 is the wind-up phase. EMG studies have determined that the rotator cuff muscles are inactive during this initial stage.
- Stage 2 is the early cocking stage and involves shoulder external rotation and abduction supplied primarily by the deltoid.
- Stage 3 is the late cocking stage, which continues until maximal external rotation is achieved. The rotator cuff muscles are very active during this stage, especially the subscapularis, which eccentrically contracts and acts as a dynamic stabilizer.
- Stage 4 is the acceleration stage, which begins with internal rotation of the humerus and ends with release of the baseball. During this phase, the pectoralis major and the latissimus dorsi are very active, whereas the muscles of the rotator cuff are inactive.
- Stage 5 is the follow-through of the baseball pitch, where deceleration takes place. During this phase, the rotator cuff muscles and the posterior deltoid are most active. The supraspinatus eccentrically contracts to decelerate internal rotation of the limb.
Proper balance between the concentrically contracting muscles that generate force and the eccentrically contracting muscles that control movement is important. Imbalance between these opposing muscle groups results in overuse of muscles and, ultimately, overuse injuries of the shoulder. Note that a great deal of the force generated in overhead sports occurs in the trunk and lower extremity, and these areas should be targeted in any conditioning program for athletes who throw.
A detailed history is important to diagnose a rotator cuff injury and can help rule out other diagnoses in the differential (eg, referred pain from the cervical spine, more serious referred symptoms of cardiac origin) (see Differential Diagnoses and Other Problems to Be Considered).
- First, determine the patient’s chief symptom (eg, pain, weakness, instability, limited ROM).
- Direct further questions at how and when the problem began.
- Determine if the patient’s symptoms are related to a specific injury or event or to a repetitive motion or are of a more insidious onset.
- Activities and arm positions that increase or decrease symptoms are also helpful in diagnosing and guiding treatment. Previous episodes of similar symptoms may give a useful clue to the patient’s present condition.
- The presence of associated symptoms (eg, instability, weakness, swelling, numbness, loss of motion, catching or popping of the shoulder) also provides helpful information.
- Ask if previous treatments have been tried, including the use of ice, heat, or medications (eg, acetaminophen, aspirin, nonsteroidal anti-inflammatory drugs [NSAIDs]).
- A social history should include the patient’s occupation and sport (including position) and level of athletic participation.
Pain, weakness, and loss of shoulder motion are common symptoms reported with rotator cuff pathology. Pain is often felt over the anterolateral part of the shoulder and is exacerbated by overhead activities. Night pain is a frequent symptom, especially when the patient lies on the affected shoulder. Symptoms may be relatively acute, either following an injury or associated with a known repetitive overuse activity. In elderly patients, symptoms are often insidious and with no specific injury. Repetitive motion can be associated with the symptoms.
Approach the shoulder examination systematically in every patient with a suspected rotator cuff injuries. Expose the entire shoulder and perform inspection, palpation, ROM testing, motor strength testing, and special shoulder tests as clinically indicated.
Examination begins with patient observation during the history portion of evaluation. Carefully inspect the shoulder from the anterior, lateral, and posterior positions. Note any swelling, atrophy, asymmetry, or other findings.
Supraspinatus and infraspinatus atrophy can be observed in massive rotator cuff tears and in entrapments of the suprascapular nerve.
Scapular winging is rare in rotator cuff injuries; however, ST motion abnormalities are often present and should be addressed as part of the treatment plan.
Tenderness is often localized to the greater tuberosity and subacromial bursa. The biceps tendon is palpated anteriorly in the bicipital groove and can become inflamed and painful in this condition.
Evaluate total active and passive ROM in all planes and scapulohumeral rhythm. Maximal total elevation occurs in the plane of the scapula, which lies approximately 30° forward of the coronal plane. Patients with rotator cuff tears tend to have a decrease in GH motion and an increase in ST motion during active shoulder elevation. Decreased active elevation with normal passive ROM is usually observed in rotator cuff tears secondary to pain and weakness. When both active and passive ROM are decreased similarly, this usually suggests onset of adhesive capsulitis.
Assess internal rotation by having the patient reach an extended thumb up the spine. Patients with normal internal rotation reach the T5-T10 level. Note that overhand throwers often develop excess external rotation (up to 15-20°) on the throwing side, which is usually accompanied by loss of internal rotation on the same side. Note any accompanying pain and specific pain location in ROM testing. The impingement syndrome associated with rotator cuff injuries tends to cause pain with elevation ranging from 60-120° when the rotator cuff tendons are compressed against the anterior acromion and coracoacromial ligament.
Perform strength testing to isolate the relevant muscles individually. The anterior cuff (subscapularis) can be assessed using the lift-off test, which is performed with the arm internally rotated behind the back. Lifting the hand away from the back against resistance tests the strength of the subscapularis muscle. The posterior cuff (infraspinatus and teres minor) is isolated best in 90° of forward flexion with the elbow flexed to 90°, testing external rotation. Significant weakness in external rotation is observed in large rotator cuff tears.
Using either of 2 techniques described in the literature can test the supraspinatus muscle. Jobe and Moynes suggested that the best position for isolating the supraspinatus is with the elbow extended, the shoulder in full internal rotation, and the arm in the scapular plane (thumbs down position).  In another report, Blackburn et al recommended testing in the prone position, with the elbow extended and the shoulder abducted to 100° and externally rotated while the patient lifts in abduction (thumbs up position).  Malanga et al noted that although both techniques significantly activate the supraspinatus muscle, neither truly isolates this muscle for testing because other muscles are active in both positions. 
Dropping of the arm in either position usually indicates a significant supraspinatus muscle tear. More subtle weakness may represent early degeneration of the rotator cuff. Testing of the scapula rotators (trapezius and serratus anterior) is also important. Serratus anterior weakness can be observed by having the patient lean against a wall. Winging of the scapula as the patient pushes against the wall indicates serratus anterior weakness.
Abduct the patient’s shoulder to 90° and ask the patient to lower the arm slowly to the side in the same arc of movement. Severe pain or inability of the patient to return the arm to the side slowly indicates a positive test result. A positive result indicates a rotator cuff tear.
Neer impingement test
The shoulder is forcibly forward flexed and internally rotated, causing the greater tuberosity to jam against the anterior inferior surface of the acromion. Pain reflects a positive test result and indicates an overuse injury to the supraspinatus muscle and possibly to the biceps tendon. See the image below.
Neer impingement test. The patient’s arm is maximally elevated through forward flexion by the examiner, causing a jamming of the greater tuberosity against the anteroinferior acromion. Pain elicited with this maneuver indicates a positive test result for impingement.
Hawkins-Kennedy impingement test
Perform this test by forward flexing the shoulder and elbow to 90° and forcibly internally rotating the shoulder. Pain indicates a positive test result and is due to supraspinatus tendon and greater tuberosity impingement under the coracoacromial ligament and coracoid process. See the image below.
Hawkins test. The examiner forward flexes the arms to 90° and then forcibly internally rotates the shoulder. This movement pushes the supraspinatus tendon against the anterior surface of the coracoacromial ligament and coracoid process. Pain indicates a positive test result for supraspinatus tendonitis.
Abduct the arm 90° and fully externally rotate, while placing anteriorly directed force on the posterior humeral head from behind. The patient becomes apprehensive and resists further motion if chronic anterior instability is present.
Perform the apprehension test with the patient supine and the shoulder at the edge of the table. In a positive relocation test result indicative of anterior instability, a posteriorly directed force on the proximal humerus causes resolution of the patient’s apprehension and usually allows more external rotation of the humerus.
Several primary causes of rotator cuff pathology have been described, including age-related degeneration, compromised microvascular supply, and primary outlet impingement. Secondary factors (eg, GH instability) also appear to be related to rotator cuff injuries.
Age-related degeneration 
Intrinsic tendinopathy is an age-related degenerative process. Uhthoff and Ozaki found an increase in frequency of partial-thickness and full-thickness tears with increasing age. Increased degenerative changes are observed in athletes and workers who perform overhead motions.
Compromised microvascular supply
- In 1934, Codman first described a critical zone in the supraspinatus tendon where a tenuous blood supply exists. 
- A decrease in vascularity is noted with aging.
- In 1970, Rathburn and Macnab showed that shoulder position is important for proper vascular supply to the rotator cuff. 
- The term “wringing out” was coined to describe the reduced blood flow that occurs upon shoulder adduction.
- The microvascular pattern of the supraspinatus tendon is thought to be nonhomogenic in cadavers. 
- In 1990, Lohr and Uhthoff found that the bursal side of the supraspinatus tendon has a higher blood supply compared to the articular surface.  This difference in blood supply is thought to contribute to the increased incidence of articular surface tears compared with bursal tears.
The rotator cuff is surrounded by the coracoacromial arch, which comprises the supraspinatus outlet and consists of the acromion, coracoacromial ligament, and coracoid process. The shape of the acromion has been implicated in rotator cuff pathology.
Bigliani and Morrison classified 3 types of acromions based on cadaveric examination, as follows  :
Type I – Flat
Type II – Curved
Type III – Hooked
Bigliani noted a significant increase in rotator cuff tears in curved (type II) and hooked (type III) acromions. This work has led to the belief that rotator cuff pathology occurs secondary to the type of acromion and that treatment should be directed toward correcting pathoanatomic changes by making the acromion smoother and flatter. However, debate exists concerning whether the acromion shape causes pathology to the rotator cuff or is a result of a diseased rotator cuff that secondarily causes bony changes to the acromion.
Neer proposed that acromial changes are secondary to rotator cuff tendinopathy.  According to this view, the initial process is migration of the humeral head superiorly with repeated impingement, followed by secondary bony changes to the undersurface of the anterior acromion. This view was further corroborated by the work of Yamanaka and Fukuda, who found a greater incidence of partial rotator cuff tears on the articular surface of the rotator cuff rather than the bursal surface.  If acromial changes actually caused rotator cuff tendinopathies, one would expect the opposite (ie, higher incidence of pathology on the bursal surface).
The rotator cuff contacts the coracoacromial arch undersurface in the normal shoulder. The coracohumeral ligament is often resected in order to decompress the supraspinatus outlet, which can lead to increased superior translation of the humeral head, particularly in the young athlete. Rotator cuff abrasions and fiber failure occur when repeated and excessive compression from humeral head migration is present. This occurs secondary to underlying muscular imbalance and loss of rotator cuff depressor effects.
Most people with ligamentous laxity are functionally stable. In patients with inherent shoulder or generalized laxity, instability may develop with minimal or no injury. Ligamentous laxity may be acquired by repetitive stretching of the joint, as observed in swimmers, gymnasts, and tennis players. Dynamic stability may be lost if the shoulder becomes deconditioned. As a result, a vicious self-perpetuating cycle of instability, less use, more muscle weakness, and more instability is present. These patients frequently have relative rotator cuff muscle weakness, particularly the external rotators and scapular stabilizers. Subtle instability patterns may contribute to the impingement development. Increased anterior and superior translation of the humeral head, as observed in athletes with generalized laxity and multidirectional instability of the shoulder, may predispose to impingement along the coracoacromial arch, resulting in rotator cuff injury.
- Differential Diagnoses
- Acromioclavicular Joint Injury
- Angina Pectoris
- Bicipital Tendonitis
- Cervical Radiculopathy
- Myocardial Infarction
- Imaging Studies
Plain radiography of the shoulder can be very helpful in the diagnosis of rotator cuff disease. Standard views should include a true anteroposterior (AP) view (in the plane of the scapula), a supraspinatus outlet view, and an axillary view. The true AP view helps determine acromiohumeral distance, which is narrowed in association with rotator cuff tears. This view also identifies sclerosis and spurring of the acromion and reactive changes at the rotator cuff insertion site on the greater tuberosity, including sclerosis and cyst formation, all of which are associated with chronic tears. The outlet view (a lateral radiograph in the scapular plane with the beam tilted 10° caudad) helps identify acromion shape and slope. The axillary view helps identify the humeral head position in relation to the glenoid. Magnetic resonance imaging (MRI) has replaced arthrography as the criterion standard for diagnosing injuries to the rotator cuff, as arthrography was found to be specific, but not sensitive, for the diagnosis of partial rotator cuff tears in adolescents.  MRI is a noninvasive imaging modality that is extremely sensitive and specific. It can be used to detect the size, location, and characteristics of rotator cuff pathology. In a rotator cuff tear, the tendon demonstrates a bright signal on T1-weighted images that increases significantly on T2-weighted images. The increased signal on T2-weighted images is fluid that is filling the defect and helps to differentiate a frank tear from tendinosis. MRI is a very costly technique that requires absolute lack of patient motion while the patient is being scanned. A small percentage of patients are unable to complete the test secondary to pain or claustrophobia.
Ultrasonography may also be used to evaluate the rotator cuff.  This modality is inexpensive, convenient, and highly accurate in detecting full-thickness rotator cuff tears. Ultrasonography can be used to characterize the extent of the rotator cuff tear and to visualize biceps tendon dislocation. One drawback to this modality is that it is extremely operator dependent, and the sensitivity and specificity of this test in detecting rotator cuff tears vary with the ultrasonographer’s skill.
EMG and nerve conduction testing are helpful in the evaluation of possible suprascapular nerve impingement and involvement of the long thoracic, axillary, musculocutaneous, spinal accessory, and brachial plexus nerves and to rule out cervical radiculopathy as a cause of shoulder pain and weakness.
Pain control and inflammation reduction are initially required to allow progression of healing and initiation of an active rehabilitation program in patients with a rotator cuff injury. This can be accomplished with a combination of relative rest, icing (20 min, 3-4 times per d), and acetaminophen or an NSAID. Have the patient sleep with a pillow between the trunk and arm to decrease tension on the supraspinatus tendon and to prevent blood flow compromise in its watershed region.
Patients are instructed to continue the pain control techniques at home, work, or vacation as part of their exercise program. The home exercise program builds on itself through each phase of the rehabilitation process, and carry-over should be monitored.
Corticosteroids delivered directly to the site via injection can be considered to allow further progression of the rehabilitation program. Place injections into the subacromial space, avoiding direct injection into the rotator cuff tendon. Advise the patient to limit activity that involves high-tensile loads (eg, maximal overhead throwing) for 2-3 weeks while the tendon is potentially at risk after injection, particularly if the patient exhibits rotator cuff muscle weakness. These injections need not be given to patients with complete rotator tears, especially if surgery is being considered.
A systematic review by Louwerens et al found that high-energy extracorporeal shockwave therapy, ultrasound-guided needling and arthroscopy all had positive outcomes for the treatment of calcific tendinopathy of the rotator cuff. 
The recovery phase from a rotator cuff injury must include several components to be successful. These include the following: (1) restoration of shoulder ROM, (2) normalization of strength and dynamic muscle control, and (3) proprioception and dynamic joint stabilization.
Restoration of shoulder ROM
After the pain has been managed, restoration of motion can be initiated. Codman pendulum exercises, wall walking, stick or towel exercises, and/or a physical therapy program are useful in attaining full pain-free ROM. Address any posterior capsular tightness because this can lead to anterior and superior humeral head migration, resulting in impingement.
Posterior capsular tightness is common in athletes performing overhead motions (particularly throwers), because the posterior muscles and capsule are greatly stressed during the follow-through phase of the throwing motion. This activity places large eccentric loads on the posterior capsule and posterior rotator cuff musculature and can result in microtrauma and inflammation, followed by scarring and contracture.
Many overhead athletes have a great degree of external rotation with restriction of internal rotation. This was once thought to be a normal adaptation to the demands of the sport. The tight posterior capsule and the imbalance it causes forces the humeral head anterior, producing shearing of the anterior labrum and causing additional injury.
Stretching of the posterior capsule is a difficult task to isolate. The horizontal adduction that is usually performed tends to stretch the scapular stabilizers and not the posterior capsule. If care is taken to fix and stabilize the scapula, which prevents stretching of the ST stabilizers, the objective of posterior capsule stretching is obtained. The focus of treatment in this early stage should be on improving range, flexibility of the posterior capsular postural biomechanics, and restoring normal scapular motion.
Initially, ultrasonography to the posterior capsule followed by gentle passive prolonged stretch may be needed. Closely monitor ultrasonography use to avoid heating an inflamed tendon, which worsens the situation. Instruct the patient about proper posterior shoulder stretches with the scapula fixed, which should be performed after a period of aerobic exercise. Such exercise results in increasing the core body temperature. The increase in core temperature makes the tissues more extensible and allows for greater benefit from stretch. Each stretch should be held for a minimum of 30 seconds, although stretching for 1 minute is encouraged.
Postural biomechanics are important because poor posture (eg, excessive thoracic kyphosis and protracted shoulders) increases outlet narrowing, resulting in greater risk for rotator cuff impingement. Restoring normal scapular motion is also essential because the scapula is the platform upon which the GH joint rotates; thus, an unstable scapula can secondarily cause GH joint instability and resultant impingement. Scapular stabilization includes exercises such as wall push-ups and biofeedback (visual and tactile).
Perform strengthening in a pain-free range only. Begin with the ST stabilizers. The scapular stabilizers include the rhomboids, levator scapulae, trapezius, and serratus anterior. Shoulder shrugs, rowing, and push-ups isolate these muscles and help return smooth motion, allowing normal rhythm between the scapula and GH joint. Then, turn attention toward strengthening the rotator cuff muscles. Position the arm at 45° and 90° of abduction for exercises to prevent the wringing out phenomenon, in which hyperadduction can be caused, stressing the tenuous blood supply to the tendon of the exercising muscle. Avoid the thumbs-down position with the arm in greater than 90° of abduction and internal rotation to minimize subacromial impingement.
Many ways to strengthen muscles are available. The rehabilitation program usually starts with isometric and co-contractions, progresses to concentric contractions, and finally incorporates eccentric contractions as part of the preparation for return to sports. Using the baseball thrower example, the most important muscle conditioning is that of eccentric control. Eccentric forces are the most damaging to muscles, and if the patient is not fully rehabilitated and conditioned, injury occurs or reoccurs.
Additional strengthening techniques that can be used are progressive resistive exercises (PREs), Thera-Band (Hygienic Corporation; Akron, Ohio), and plyometrics. Use of isokinetic exercises has been debated because they are not performed in a functional manner. Probably the best use for isokinetic exercise machines is for objective side-to-side comparison of strength and progress made in strength rehabilitation. Incorporate endurance training into the program as it advances. When strength is restored, continue a maintenance program for fitness and prevention of reinjury.
Proprioceptive training is important to retrain neurologic control of the strengthened muscles, providing improved dynamic interaction and coupled execution of tasks for harmonious movement of the shoulder and arm. Begin tasks with closed kinetic chain exercises to provide joint stabilizing forces. Then, as the muscles become reeducated, one can progress to open chain activities, which may be used in sports or tasks.
Capsuloligamentous structures contain sensory afferents, which respond to motion and changes in joint position, whereas musculotendinous structures sense muscle length and tension. Injury can affect these afferents, which require retraining much like restrengthening the muscles. In addition, proprioceptive neuromuscular facilitation (PNF) is designed to stimulate muscle/tendon stretch receptors for reeducation. In a 1965 report, Kabat described shoulder PNF techniques in detail. 
Indications for operative treatment of rotator cuff disease include partial-thickness or full-thickness tears in an active individual who does not have improved pain and/or function within 3-6 months with a supervised rehabilitation program. An acromioplasty is usually performed in the presence of a type II (curved) or type III (hooked) acromion with an associated rotator cuff tear. Athletes with rotator cuff pathology secondary to GH instability also need to have this addressed. Surgical treatment of a shoulder rotator cuff injury is reliable, and it provides good clinical results in patients who were operated on within the first 3 weeks after the injury. 
In surgical candidates, early repair is useful to avoid fatty degeneration and retraction of the remnant rotator cuff musculature. Functional recovery should be stressed, and, in a patient who can achieve pain-free activities of daily living in the setting of a rotator cuff tear, surgical repair may be avoided. Surgeries including muscle transfers and debridement are generally reserved for massive, irreparable rotator cuff tears. A latissimus dorsi tendon transfer is one type of treatment for irreparable rotator cuff tears that has demonstrated improvement in shoulder function, range of motion, strength, and pain relief. 
Attempts to enhance healing in rotator cuff repair have included the use of platelet-rich fibrin matrix applied to the tendon-bone interface at the time of rotator cuff repair; this technique, however, has no demonstrable effect on tendon healing or vascularity, manual muscle strength, or clinical rating scales. Whether fibrin matrix is the ideal substrate to enhance tissue healing remains unknown, and perhaps other forms of growth factors may prove to be better at enhancing tissue healing following surgery. 
Kissenberth et al observe that the tangent sign is an easily performed and reproducible tool with good intraobserver and interobserver reliability that is a powerful predictor of whether a rotator cuff tear will be repairable. 
Deniz et al evaluate the changes in fatty degeneration and atrophy of rotator cuff muscles after arthroscopic repair. The authors found that initial muscle atrophy and fatty degeneration did not improve even after a successful rotator cuff repair where the tendon anatomic integrity was maintained for at least 2 years. 
Return to task-specific or sport-specific activities is the last phase of rehabilitation. This phase is an advanced form of proprioceptive training for the muscles to relearn previous activities. It is an important phase of rehabilitation and should be supervised properly to minimize the possibility of reinjury. Rehabilitation begins at a cognitive level but must be practiced so that transition to unconscious motor programming occurs. All various phases of shoulder injury rehabilitation may overlap and can progress as rapidly as tolerated, but all should be performed to speed recovery and prevent reinjury.
At the conclusion of formal therapy sessions, patients should be independent in an ROM and strengthening program and should continue these exercises, initially under supervision and then completely on their own. A natural tendency exists for patients to abandon the home program once they feel better; however, patients must be encouraged to continue a maintenance exercise program to prevent symptom relapse. Athletes are often tempted to return to their overhead throwing sport too soon after recovery of the acute phase.
A meta-analysis by Mazuquin et al of 10 systematic reviews and 11 randomized-controlled trials of patients who underwent surgery repair for chronic rotator cuff tears found little difference between early and conservative rehabilitation after surgical repair in terms of function, pain, range of motion, and retear ratio. 
NSAIDs are frequently used at the onset of rotator cuff injuries to reduce inflammation and control pain. Currently, good clinical studies justifying routine NSAID use are not available. In addition, adverse effect profiles and patient tolerance of NSAIDs may preclude their use in some cases. Various NSAIDs are available over the counter or by prescription. Use proper doses in the acute phase of rotator cuff injuries for a few days to a week, and stop when pain and inflammation begin to subside.
Nonsteroidal Anti-inflammatory Agents (NSAIDs)
NSAIDs have analgesic and antipyretic activities. The mechanism of action of these agents is not known, but they may inhibit cyclooxygenase (COX) activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell-membrane functions. Treatment of pain tends to be patient specific.
Ibuprofen (Motrin, Ibuprin)
DOC for mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.
Ketoprofen (Actron, Orudis)
- For the relief of mild to moderate pain and inflammation.
- Small dosages are initially indicated in small and elderly patients and in those with renal or liver disease.
- Doses >75 mg do not increase therapeutic effects. Administer high doses with caution, and closely observe patient for response.
Naproxen (Naprosyn, Naprelan, Anaprox)
For the relief of mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing activity of COX, which results in a decrease of prostaglandin synthesis.
Return to Play
Return to play criteria should be individualized for every player.  General criteria require the athlete to experience no pain with rest or activity, full strength in muscles across the affected joint, pain-free shoulder ROM with normal ST motion, and negative provocative tests (eg, Neer impingement test, Hawkins impingement test).
An athlete who returns to his or her sport too soon tends to alter throwing mechanics and risks injuries not only to the same shoulder, but also to the elbow, hip, and spine. Resumption of activities should be gradual, and activity intensity may need to be modified in response to recurrence of symptoms. Imaging findings alone should not be used to determine return to play.
When treatment is delayed in rotator cuff injuries and shoulder discomfort persists, the patient can develop symptomatic stiffness of the GH joint, which is called adhesive capsulitis. In this condition, the patient consciously or subconsciously limits the use of the shoulder because of pain, leading to the development of soft-tissue tightness or stiffness in one or more planes. The chance of developing adhesive capsulitis can be minimized through prompt diagnosis of painful problems in the shoulder, such as rotator cuff injuries, and the institution of early shoulder ROM as part of the rehabilitation program.
Severe supraspinatus and infraspinatus muscle atrophy is often associated with massive rotator cuff tears, but an underlying entrapment of the suprascapular nerve should always be considered. Symptoms of suprascapular nerve entrapment include shoulder pain that is described as a deep dull ache localized to the posterolateral aspect of the shoulder. Weakness of the shoulder and arm is common, with visible wasting and atrophy of the supraspinatus and infraspinatus and normal bulk in the deltoid. Clinical differentiation of suprascapular nerve entrapment from rotator cuff injuries may be difficult, especially if both are present simultaneously. EMG is the single most helpful test for diagnosing this condition.
Following rotator cuff injuries, patients must pay careful attention to the use of proper mechanics during athletic activities and avoid harmful adaptations (eg, changing arm position when throwing a baseball). The nature of many overhead sports makes the athlete susceptible to injury and dysfunction because of the repetitive high-velocity stress that is required.
Athletes should maintain balanced shoulder ROM, paying particular attention to shoulder internal rotation, which can be limited by increased posterior capsular tightness. Dynamic stabilizers should be strengthened, including the rotator cuff muscles and the scapula stabilizers. This decreases demands on the static stabilizers (eg, bony structures, labrum, ligaments, capsule) and helps the athlete minimize the risk of injury. Maintaining proper trunk and lower extremity strength is also important, because these muscles generate significant force for athletes performing overhead motions and reduce stress on the shoulder girdle muscles.
Most athletes with primary outlet impingement without full-thickness rotator cuff tears respond well to nonoperative treatment. Rehabilitation is also effective in the majority of athletes with rotator cuff pathology due to other causes (eg, instability), except when instability is caused by trauma. When surgery is performed for rotator cuff injuries not responding to conservative treatments, results vary depending upon patient age, size and pattern of the tear, degree of retraction, tissue quality, and quality of repair.
One study evaluated 51 patients, aged 60 years or younger, with nonoperatively treated rotator cuff tears and found that full-thickness rotator cuff tears tended to increase in size in about half of the patients. The study suggests that surgery be considered to prevent an increase in size tear, and those treated nonoperatively should be monitored for tear size increase. 
Proper sport technique can be of great importance in the prevention and rehabilitation of rotator cuff injuries. This includes proper hand position on water entry in swimming, changes in paddling technique in canoeing and kayaking, and evaluation of pitching mechanics by coaches and trainers in throwing athletes. Encourage the importance of maintaining proper trunk and lower extremity strengthening in athletes performing overhead motions, because these muscles generate significant force during overhead activities and serve to reduce stresses on the shoulder stabilizers.
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