rotator cuff anatomy and its pathologies

rotator cuff anatomy and its pathologies

1. Rotator cuff disease Dr. Mehraj (PG2) Dr. Mary Dorothy (PG1)

2. Rotator Cuff: • an anatomical term given to the group of muscles & their tendons that act to stabilize the shoulder. • These muscles are : 1 . Supraspinatus . 2. Infraspinatus. 3. Teres minor . 4. Subscapularis .

3. They Fuse together with the articular capsule into a common insertion on the tuberosities of the humerus, which is known as the footprint of the rotator cuff.

4. Important functions: • Counterbalance the upward pull of the deltoid on the Humerus. • Hold the head of the humerus secure in the glenoid. • Externally rotate the shoulder which is important during arm elevation.

5. Function of Rotator Cuff Is to hold the head of humerus in the small and shallow glenoid fossa of the scapula. During elevation of the arm, the rotator cuff compresses the glenohumeral joint in order to allow the large deltoid muscle to further elevate the arm.

6. The subacromial space : Its the under the surface of the acromion and the under surface of the coracoid process of the scapula with the coracoacromial ligament (aka “roof of shoulder”) stretched between them the roof of spac e is formed by the coracoacromial arch and the acromioclavicular joint. The floor of the space is formed by the greater tuberosity and upper portions of the humeral head. The space is occupied by the rotator cuff tendons, the tendon of the long head of biceps brachii and the subacromial and subdeltoid bursae .

7. Rotator interval is a triangular structure that lies between superior aspect of subscapularis tendon and anterior aspect of supraspinatus tendon. The base of triangle is located at coracoid. The interval contains coracohumeral ligament (protecting supraspinatus tendon and restraining inferior translation of humerus in adduction), SGHL and transverse humeral ligament (protecting the biceps tendon and roofing the bicipital tunnel).

8. • Vascular supply and anomalies : Rotator cuff is supplied by anterior branch of ascending humeral circumflex artery, acromial branch of thoracoacromial artery and the subscapular and posterior humeral circumflex arteries. There is a debate on the vascular supply of the critical zone (8–10 mm proximal to insertion) of supraspinatus tendon. It seems that the neovascularization is in fact secondary to the impingement rather than being the cause of degeneration of tendon.

9. ETIOLOGY injury to 1 or more of the 4 muscles in the shoulder. This shoulder injury may be sudden or be associated with a specific injury such as a fall (acute) , or it may be something that gets progressively worse overtime with activity that aggravates the muscle(s) (chronic). can range from an inflammation of the muscle without any permanent damage, such as tendinitis, to a complete or partial tear of the muscle that might require surgery to fix it

10. Tests : Drop arm test is helpful in diagnosing massive rotator cuff tear. The examiner abducts the patient’s shoulder to more than 90° and then asks the patient to hold it in that position as the examiner withdraws support The patient with a rotator cuff tear will not be able to hold it and the arm will drop down suddenly. The drop of the arm may be accompanied by severe pain. Horn blower’s sign will test the integrity of infraspinatus and teres minor tendons. The patient’s elbow is flexed to 90° and then arm is elevated to 90° of abduction. Patient rotates the arm externally against examiner’s resistance Weakness indicates incompetency in one of the components while test is positive if there is pain and or inability to maintain the externally rotated position. In complete rupture as in massive rotator cuff tears the arm drops back to neutral position.

11. The “lift off test” assesses the integrity of the lower subscapularis muscle Another test is the “belly press test” which requires less internal rotation and tests the upper portion of subscapularis. The patient presses against the belly with wrist extended and elbow in front of body. “Napoleon test” is a further modification of “belly press test”. Here the patient puts his hand on belly with elbow resting by his side, then he is asked to bring the elbow forward/anteriorly while maintaining the position of hand. Positive test is when patient is unable to bring the elbow to front without moving the shoulder girdle. “Bear hug test” also assesses subscapularis muscle. In this test, the patient cross his hand and keeps it over the other shoulder. He is asked to push against the shoulder down where a subscapularis muscle produces pain.

12. Test Finding Muscle Drop arm test Patient unable to maintain arm in 90° elevation Supraspinatus External rotation lag test Patient unable to maintain arm in maximum external rotation in adduction Infraspinatus Hornblower sign Patient unable to maintain arm in external rotation 90° abduction, 90° external rotation Teres minor Belly press test Pain while pressing on abdomen with hand and elbows anterior to midsagittal plane of body Upper subscapularis Lift-off test Patient unable to maintain hand off lumbosacral spine in full internal rotation Lower subscapularis

13. Investigations: Radiographs are helpful in diagnosing a variety of pathologies. In shoulder instability, glenoid bone loss can be, at times, seen in an axillary view, humeral head bone loss (Hill-Sachs lesion) in the AP and axillary views, subacromial spurs, ossification of coracoacromial ligament in outlet views. Scapular Y-view also helps to evaluate the shape of acromion. Bigliani et al. classified acromion into three types : Type I : A flat acromion Type II : A curved acromion Type III : An anterior downward hook on the acromion.

14. Ultrasonography: Ultrasonography has been reported to detect full-thickness tears in 92–95% cases. Absence of cuff motion on real time ultrasound is a reliable sign for full-thickness cuff tear. Computed tomography scans are very helpful in assessing glenoid bone loss and humeral head in recurrent instabilities.

15. Ultrasonography • Dynamic Non - invasive Inexpensive Helpful as a screening tool •USG guided Injection

16. Magnetic Resonance Imaging (MRI) and Magnetic Resonance (MR) Arthrography Magnetic resonance imaging (MRI) and magnetic resonance (MR) arthrography can diagnose a variety of lesions of the shoulder with great accuracy. The MRI is done in three planes, i.e. axial, oblique coronal and oblique sagittal. In the axial plane, the glenoid labrum with the ligaments, humeral head, subscapularis tendon and the biceps tendon (Fig. 2) can be visualized. In the oblique coronal plane the acromioclavicular (AC) arch and the rotator cuff tendons and muscles are visualized. In the oblique sagittal plane, the supraspinatus tendon, the AC joint, the biceps anchor and the subacromial bursa are seen.

17. Rotator Cuff Disease: It encompasses the full spectrum including : 1. impingement syndrome, 2. subacromial bursitis, 3. supraspinatus tendinitis and 4. rotator cuff tear.

18. SUBACROMIAL IMPINGEMENT SYNDROME often precedes nontraumatic cuff tears normal rotator cuff function, the humeral head translates less than 3 mm superiorly during the midranges of active elevation, whereas at extreme movements, anteroposterior and superoinferior translations of 4–10 mm do occur. An increase in superior translation with active abduction may result in encroachment of the coracoacromial arch. This encroachment produces a compression of the suprahumeral structures against the anteroinferior aspect of the acromion and coracoacromial ligament . Repeated compression of these structures, when coupled with other predisposing factors, results in SIS.

19. Types of impingement : 1.the outlet (intrinsic) impingement, and 2.the nonoutlet (extrinsic) impingement. “Outlet impingement”, classically described by Neer, is called so because it occurs at the supraspinatus outlet formed by the coracoid process, the anterior acromion, the AC joint, and the coracoacromial ligament. The term impingement syndrome refers to this outlet impingement per se. It is thought to be the cause of symptoms in 90–95% cases, however, with better understanding and evaluation of elderly, the role of degenerative changes is gathering importance.

20. Neer divided the outlet impingement process into three stages, although the condition is a continuum of symptoms. These stages have specific findings and the intrinsic or extrinsic factors contributing to the problem. 1. Stage I : This stage consists of localized inflammation, and edema of the rotator cuff typically observed in younger (<25 years of age) patients, although it can also be seen in older patients as a result of overuse The patient has painful shoulder and a history of associated trauma or microtrauma. There is tenderness at the supraspinatus insertion and anterior acromion, the range of motion (ROM) is painful, and weakness arises due to pain. Scapular stabilization is jeopardized due to painful inhibition of the serratus anterior and trapezius. 2. Stage II : This represents a progressive deterioration in the tissues of the rotator cuff typically seen in the 26- to 40-year-old age group. With continued irritation of the subacromial structures, secondary changes develop in the tissues . The subacromial bursa loses its ability to lubricate and tendonitis of the cuff develops. Especially the overhead activities are painful with pain commonly located on the top of the shoulder radiating to arm in the deltoid insertion region.

21. 3. Stage III : This is the end stage with destruction of the soft tissue and tear of the rotator cuff. It is commonly seen in patients above 40 years age group. The wear of the anterior aspect of the acromion on the greater tuberosity and the supraspinatus tendon eventually results in a full-thickness tear of the rotator cuff. Degeneration of nearby AC joint is seen with osteophyte formation . Muscle atrophy is quite prominent especially of the infraspinatus and supraspinatus. There is progressive limitation in active and passive ROM. Rotator cuff tears hence develop

22. Nonoutlet Impingement or Posterior Superior Glenoid Impingement This is a newly recognized source of rotator cuff pathology seen in athletes performing repetitive overhead motions and is associated with superior labrum anterior and posterior (SLAP) lesions (possibly they represent a spectrum of the disorder). It has been found that a triad of anterior capsular laxity, posterior contraction and internal impingement occurs in overhead athletes. It results from impingement of the in-folded rotator cuff between the greater tuberosity and the posterior superior glenoid labrum during forced humeral elevation and internal rotation. During extreme overhead abduction, the articular surface of the cuff gets stuck between the posterosuperior labrum and humeral head Also stress concentration has been found to occur in the so-called critical zone of cuff in varying degrees of abduction. This leads to degenerative tears being initiated on the articular side, bursal side and the intratendinous portion. This can eventually result in posterior superior tears in the glenoid labrum (reverse bankart lesion), and lesions in the posterior humeral head.

23. Primary and Secondary Impingement Jobe and Pink proposed two other types of impingeme nt, which relate to chronic disorders of the rotator cuff. Primary impingement same as outlet impingemen t of Neer occurs when the superior aspect of the rotator cuff is compressed and abraded by the surrounding bony and soft tissues due to a decreased subacromial space. In primary impingement, the impingement itself creates the clinical presentation so that treatment should be directed to the impingement itself. 2. Secondary impingement is a condition found in both older and younger individuals. This type results in tensile overload of the rotator cuff resulting in poor control of the humeral head during overhead activities and may be associated with instability. In secondary impingement, the signs and symptoms are those of impingement; however, they result from factors other than impingement of the tissues “directly”, e.g. instability of shoulder might lead to secondary impingement of the tissues as in the posterosuperior corner or scapular dyskinesis . 3. Apart from SIS, another entity called “subcoracoid impingement” has also been described. The condition arises from a laterally placed coracoid process that impinges on proximal humerus with forward flexion and internal rotation.

24. Rotator Cuff Tears: The current understanding of rotator cuff pathology can be summarized into four mechanisms: Tensile overload : The rotator cuff is subject to stretching forces when it attempts to resist horizontal adduction, internal rotation, anterior translation and distraction forces eventually damaging the collagen fibers. Compression : Compression of the cuff can either be primarily due to a reduction in the size of the subacromial space, or secondary (dynamic) due to joint instability. Internal impingement : Stretching and impingement of the rotator cuff tendons in internal impingement leads to articular side tear of supraspinatus and infraspinatus [partial articular surface tendon avulsion (PASTA)].

25. Acute trauma : Tearing of the tendon results when forces generated by the trauma exceed the tensile strength of the tendon. These pathologies include AC joint arthritis and sometimes the involvement of glenohumeral articulation. The long head of biceps may be involved with fraying or detachment . Some uncommon findings include the presence of os acromiale (8% of population) and suprascapular nerve compression pathology. The suprascapular nerve compression can cause shoulder pain and weakness mimicking full-thickness supraspinatus and/or infraspinatus tears. The compression can also come secondary to excessive retraction (>2 cm) following complete tear of tendon. Rotator cuff tears have been classified according to the depth (full- versus partial-thickness), etiology (traumatic vs degenerative), age of the tear (fresh vs chronic with secondary changes), size (partial to massive), and number of tendons involved (single, multiple to massive). The Patte classification is the most elaborate system and includes anatomic and pathologic considerations that are important for defining an individual treatment plan for each patient.

26. Patte classification of rotator cuff tears Extent of Tear: • Group I : Partial tears or full-substance tears less than 1 cm in sagittal diameter at bony detachment ▪ Deep, partial tears ▪ Superficial tears ▪ Small, full-substance tears • Group II : Full-substance tears of entire supraspinatus • Group III : Full-substance tears involving more than one tendon • Group IV : Massive tears with secondary osteoarthritis

27. Topography of Tear in Sagittal Plane • Segment 1: Subscapularis tear • Segment 2: Coracohumeral ligament tear • Segment 3: Isolated supraspinatus tear • Segment 4: Tear of entire supraspinatus and one half of infraspinatus • Segment 5: Tear of supraspinatus and infraspinatus • Segment 6: Tear of subscapularis, supraspinatus and infraspinatus Topography of Tear in Frontal Plane • Stage 1: Proximal stump close to bony insertion • Stage 2: Proximal stump at level of humeral head • Stage 3: Proximal stump at level of glenoid Quality of Muscle • Minimal fatty streaking • Less fat than muscle • Equal fat and muscle • More fat than muscle State of the Biceps Tendon • Intact • Subluxated • Dislocated

28. THANKYOU