Shoulder

Question 1

Muscle length-force relationship

Answer 1

Maximum contraction strength cannot be achieved when a muscle is placed in a position outside of its native resting length.
Therefore, the reliability of muscular strength testing depends on the clinician’s knowledge of correct testing positions that are designed to optimise the length-force relationship of the particular muscle being tested.

Question 2

Muscle isolation

Answer 2

Complete isolation of a single muscle for the purpose of strength testing is a nearly impossible task.
It is more advantageous to isolate the overall function of specific groups of muscles rather than attempting to isolate each muscle individually.
It is necessary to develop a consistent, repeatable examination protocol which can improve individual diagnostic efficiency and accuracy.

Question 3

Limitations of Manual muscle testing

Answer 3

1. Subjective in nature
2. Inability to detect small, between level differences in strength
3. Not capable of detecting clinically relevant differences in muscle strength

Question 4

Strength screening

Trapezius

Answer 4

Patients with trapezius weakness may have difficulty elevating the humerus above the horizontal plane due to the inability to initiate upward rotation of the scapula.

The upper fibres of the trapezius muscle are tested by simply asking the patient to shrug their shoulders against resistance.

The middle trapezius is most easily tested with the patient in the prone position with the arm hanging over the side of the table in 90 degrees of forward flexion. the examiner then places their hand distally and applies a moderate downward force while the patient resists. (care must be taken to rule out anterior instability before performing this test)

To test the lower fibres of trapezius, the patient is placed in the prone position with the arm abducted to approximately 120 degrees within the scapula plane. This position aligns the upper extremity with superolaterally directed fibres of the lower trapezius. From this position, the subject then attempts to extend the arm upward while the examiner both applies resistance and simultaneously examines the scapula for any evidence of winging.

Question 5

Strength screening

Rhomboids

Answer 5

The rhomboid musculature consists of both the rhomboid major and minor which, on some occasions, exist as a single muscle-tendon unit.

To test the rhomboids, the patient is asked to place the hands on the iliac crest with the thumbs pointed posteriorly and with the elbows in neutral position. The patient is then asked to resist an anteriorly directed force applied to the medial epicondyles such that the elbows are pushed anteriorly into a flared position. Medial scapular border can be palpated while the test is being performed.

Question 6

Strength screening

Serratus Anterior

Answer 6

Scapular winging due to global weakness of the serratus anterior can be elicited by simply having the patient actively forward flex both arms to 90 degrees of elevation while simultaneously observing the dynamic motion of both scapulae.

Performing wall push up is more sensitive for the detection of both mild and severe serratus anterior weakness in a busy clinic setting.

Question 7

Strength screening

Latissimus Dorsi

Answer 7

Clinically, the latissimus dorsi is tested with the patient in the prone position and the arms at the side (slight abduction). The patient is then asked to simultaneously extend and internally rotate the humerus while the examiner applies resistance.

Question 8

Strength screening

Supraspinatus

Answer 8

The isolated primary functions of the supraspinatus muscle are to abduct the humerus and to act as a physical barrier to prevent superior migration of the humeral head.

The most popular supraspinatus strength test was one proposed by Jobes, the empty can test. However EMG studies have shown that Empty can test does not fully isolate the supraspinatus muscle and that other muscles, particularly the anterior and middle portions of the deltoid muscle, contribute significantly to strength in these positions (deltoid and supraspinatus work synergistically to abduct the humerus)

The ability to achieve an empty can position may be difficult for some patients due to guarding and pain, especially as IR of the humerus positions the shoulder inn impingement position.

A study by Kelly et al found no difference in EMG activity between empty can, full can or neutral positions, indicating that supraspinatus testing can probably be estimated using any of these positions.

Question 9

Strength screening

Infraspinatus

Answer 9

It is generally accepted that the optimal position for testing infraspinatus strength is with the humerus at the side in neutral rotation with the elbow flexed at 90 degrees.

Question 10

Strength screening

Subscapularis

Answer 10

Resisted internal rotation in the neutral position (arm at the side in neutral position with the elbow flexed to 90 degrees) electrically activated the subscapularis more than any other muscle at teach tested position; however the muscle is probably best isolated when the humerus is abducted to 90 degrees within the scapular plane in neutral rotation.

Question 11

Strength screening

Teres Minor

Answer 11

The teres minor is primarily an external rotator with the humerus at 90 degrees of abduction within the scapular plane.

Screening for teres minor weakness can be performed by simply having the patient abduct the humerus to 90 degrees in neutral rotation with the elbow flexed to 90 degrees and resisting external rotation from this position.

Question 12

Strength screening

Teres Major

Answer 12

Physical examination to detect weakness of the teres major have not been developed. However, the primary function of the teres major muscle is to adduct, extend and internally rotate the humerus, similar to the latissimus dorsi

Question 13

Strength screening

Deltoid

Answer 13

In reality, all 3 divisions of the muscle are active with nearly any movement of the arm in any direction.

Testing the individual components of the deltoid muscle is probably not routinely necessary unless one suspects axillary nerve dysfunction.

To test the anterior deltoid, the patient is in the sitting position with the humerus at the side and the elbow flexed to 90 degrees. We then ask the patient to make a fist and to push forward against resistance applied by the examiner.

The middle deltoid can be tested in 70 degrees of straight lateral abduction where further abduction is resisted.

Posterior deltoid is tested by resisting active extension in standing

Question 14

Strength screening

Biceps Brachii

Answer 14

The biceps muscle function primarily to supinate the forearm and to flex the elbow

Question 15

Strength screening

Triceps Brachii

Answer 15

The main function of the triceps muscle is to extend the elbow joint

Question 16

Strength screening

Pectoralis Major

Answer 16

The muscle is tested by first having the patient forward flex both arms to 90 degrees of elevation with each humerus internally rotated.

Question 17

Strength screening

Pectoralis Minor

Answer 17

Based on the orientation of its fibres, the pectoralis minor has been theorised to primarily cause scapular protraction and internal rotation.

Question 18

Subacromial impingement

Pathogenesis involving extrinsic factors

Answer 18

Neer originally described subacromial impingement as the repeated contact between the greater tuberosity and the under surface of the acromion and coracoacromial ligament. He described 3 basic stages in the development of the impingement syndrome

Stage 1 of impingement, occurring asymptomatically in patients younger than 25 years of age, involves subacromial edema, haemorrhage and bursitis. Between the ages of 25-40, continued impingement results in RC fibrosis and tendinitis, eliminating the normal lubricating effects of the subacromial bursa. Beyond the age of 40 years, continued impingement becomes more symptomatic with the development of acromial spurs along with partial - and full -thickness rotator cuff tears.

Question 19

Subacromial impingement

Coracohumeral Ligament

Answer 19

The coracoacromial ligament originates from the distal-lateral extension of the coracoid process and travels posterolaterally to insert upon the antero-lateral margin of the acromion.
One cadaveric study found that shoulders with rotator cuff tears and clinical evidence of impingement had stronger, thicker anterolateral bands compared to shoulders with unrelated issues.
Evidence of traction spur formation within the anterolateral band has also been found which further implicates its involvement with the development of impingement. Yamamoto found that the superior cuff made contact with and generated increased tension through the coracoacromial ligament during ROM testing in a series of normal, healthy shoulders. This findings may provide at least one possible explanation behind the development of traction-type spurs on the anterolateral acromion with advancing age, potentially leading to extrinsic compression of the superior cuff tendons.

Question 20

Subacromial impingement

Os Acromiale

Answer 20

Developmental abnormality of acromion where there is failed fusion of secondary ossification centre is called os acromiale.
Os acromiale is a mobile accessory ossicle that, when unstable and pulled inferiorly by contraction of the deltoid with arm elevation, has been associated with the development of identifiable impingement lesions and pain at the top of the shoulder.

Further study is needed to clarify the effects of os acromilae on normal RC tendons.

Question 21

Subacromial impingement

Acromial morphology and glenoid version

Answer 21

The anterior aspect of the acromion may, in itself, be a potential site of RC abrasion and subsequent tearing regardless of the presence or absence of space-occupying traction spurs associated with the coracoacromial ligament.

Question 22

Subacromial impingement

Pathogenesis involving extrinsic factors

Answer 22

While extrinsic factors probably have some role in the development of subacromial impingement, many authors believe that the initiation and progression of rotator cuff disease primarily occurs as a result of intrinsic cuff degeneration. They argue that degenerative changes and/or traumatic injuries weaken the contractile strength of supraspinatus muscle which predictably leads to superior humeral head migration and cuff impingement beneath the acromion with humeral elevation.

The deterioration of tendon quality due to advanced age is often implicated as one of the primary causes of rotator cuff weakness, potentially resulting in proximal humeral head migration, subsequent bursal irritation and cuff tendinopathy.

The tenuous microvascular blood supply to the supraspinatus and infraspinatus tendons has also been suggested as a possible intrinsic factor related to the development and progression of certain rotator cuff tears. the most distal 15mm of supraspinatus and infraspinatus insertion sites on the greater tuberosity has been found to be hypovascular. Some authors believe these findings are the result of cuff degeneration rather than the cause of cuff degeneration.

Question 23

Subacromial Impingement
Physical examination

Neer Impingement sign

Answer 23

Passive and maximal forward elevation of the humerus and stabilisation of the scapula with the examiner’s contralateral hand. Stabilisation of the scapular is essential to maximise the utility of the test since upward rotation of the scapula (and therefore the acromion) with forward elevation will decrease the likelihood of reproducing cuff impingement under the acromion. Reproduction of patient’s symptoms is indicative of a positive test.

Hegedus et al found that overall sensitivity of the Neer impingement sign was 72% while its overall specificity was approximately 60%.

Combination of results with those obtained from the Hawkins-Kennedy test and the painful arc sign are likely to improve the diagnostic accuracy.

Question 24

Subacromial Impingement
Physical examination

Hawkins-Kennedy test

Answer 24

A positive Hawkins-Kennedy test is the result of greater tuberosity contact on the undersurface of the coracoacromial ligament that is though the reproduce symptoms related to subacromial impingement.
To perform this test, the shoulder is brought to 90 degrees of abduction in the scapular plane with the elbow also flexed 90 degrees. From this position, the humerus is slowly and maximally internally rotated.
Reproduction of patient’s symptoms (typically pain over the anterior shoulder) is deemed a positive test and may be indicative of superior cuff impingement.

Question 25

Subacromial Impingement
Physical examination

Painful arc sign

Answer 25

The painful arc sign is elicited with resisted abduction of the shoulder in the scapular plane with the elbow in full extension.

Question 26

Subcoracoid Impingement

Pathogenesis

Answer 26

Subcoracoid impingement is a potential cause for anterior shoulder pain as a result of compression of the subscapularis between the posterolateral edge of the coracoid process and the lesser tuberosity of the humerus. In contrast to subacromial impingement which likely involves a multitude of intrinsic and extrinsic factors, most authors agree that many subscapularis tears associated with a narrowed coracohumeral interval are most likely caused by external tendon compression.

Patients with anterior glenohumeral instability present with subcoracoid impingement due to increased anterior translation of the humerus which subsequently narrows the coracohumeral interval.

Question 27

Subcoracoid Impingement
Physical examination

Subcoracoid impingement test

Answer 27

Patients with subcoracoid impingement typically complain of dull pain over the anterior aspect of the shoulder. This pain may radiate distally along the brachium if the long head of the biceps tendon is involved. Although patients typically present with full ROM, they typically present with pain over the coracoid that is exacerbated by forward flexion, internal rotation and cross-body adduction.

Subcoracoid impingement remains a diagnosis of exclusion when all other causes of anterior shoulder pain have been ruled out. Despite the lack of literature on the subject, it is important to remember that subcoracoid impingement may be result of disordered scapular mechanics. Thus, it is critically important to evaluate the scapula in patients suspected of having subcoracoid impingement.

The subcoracoid impingement test, which is a modified version of the Hawkins-Kennedy test, is useful to perform in any patient with shoulder discomfort, especially anteriorly. The test is performed by placing the patient’s arm in 90 degrees of forward flexion, submaximal internal rotation and 90 degrees of elbow flexion. From this position, the patient’s arm is progressively adducted and internally rotated. Onset of dull anterior shoulder pain is sign of positive test.

Because this maneuver is similar to the cross-body adduction test for AC joint pathology, it is important to note the precise location and quality of the pain that is generated by the test.

Because the subscapularis muscles makes a significant contribution to the bicipital sheath, testing for pathology of the LHB tendon is also indicated when subcoracoid impingement is suspected.

Question 28

Symptomatic Internal Impingement

Answer 28

The term internal impingement refers to a normal physiologic occurrence where the greater tuberosity makes contact with the posterosuperior glenoid labrum when the humerus is abducted and externally rotated. Although its primary function may be involve the prevention of hyper-external rotation and maintenance of stability, repeated episodes of this impingement may lead to posterosuperior labral tears and posterosuperior RC tears which eventually become symptomatic. In essence, the posterosuperior labrum and RC become pinched between the greater tuberosity and the bony glenoid rim leading to posterior shoulder pain especially when the humerus is abducted and externally rotated.

Question 29

Rotator Cuff Tears

Pathogenesis

Answer 29

The different etiologies of rotator cuff tears are most often multifactorial, ranging from acute traumatic injuries to the 3 main types of mechanical impingement that can each progress rotator cuff tearing.
In acute injuries, patients will typically recall the specific events leading to their shoulder pain, weakness and dysfunction.
Without treatment, small tears with intact GH mechanics can progress to larger tears, leading to weakness and unbalanced force couples and, subsequently, increased shoulder pain and dysfunction.

Subacromial impingement involves a combination of intrinsic factors and extrinsic factors that lead to the insidious onset of pain especially a night and/or with overhead activities. As the cuff tear develops and increases in size, pain and weakness become the predominant features. Pain and weakness becomes worse as the tear extends to involve other tendons, such as those of the infraspinatus (posterosuperior tear) or subscapularis (anterosuperior tear). Left untreated, pain will often diminish and the patient will complain of weakness as the primary symptom.

Subcoracoid impingement is thought to result from a narrowed coracohumeral interval and presents with an insidious onset of dull pain over the anterior aspect of the shoulder is positions of adduction and IR. Similar to subacromial impingement, the progression of small, structural lesions of the subscapularis can lead to large, full-thickness tears resulting in progressive pain, dysfunction and, in some cases, anterior instability.

Symptomatic internal impingement occurs a result of repetitive hyperabduction and ER which leads to posterosuperior articular sided RC tears and labral lesions.

Question 30

Rotator Cuff tears
Physical examination

Supraspinatus

Answer 30

Supraspinatus tendon tears are initially suspected during the initial surgery as a result of specific historical findings and the presence of pain and/or weakness with GH abduction.
Furthermore, since painful impingement of the rotator cuff may progress to partial- or full-thickness tears, positive impingement signs may also be present in patients with weakness associated with a rotator cuff tear.

Jobe test: The arm is passively placed in 90 degrees in the scapular plane with the thumbs pointed downward
From this position, the examiner places their hands on the top of the patient’s forearms and applies a downward pressure while the patient resists. A positive test occurs when asymmetric weakness occurs in the affected shoulder.
To alleviate some of this pain and to more directly evaluate supraspinatus strength, the test can be repeated with the thumbs pointed upward.

Drop arm sign: In some patients with massive supraspinatus tears, the patient may be unable to hold the arm abducted against the force of gravity as the arm drops back to the patient’s side.

Question 31

Rotator Cuff tears
Physical examination

Infraspinatus

Answer 31

The identification of an external rotation deficit is initially found during the general strength survey with the resisted external rotation maneuvers.

External Rotation lag sign: To elicit the ER lag sign, the arm is kept at the patient’s side and the elbow is flexed 90 degrees. From this position, the humerus is passively placed in 20-30 degrees of external rotation. A positive ER lag sign occurs when the patient is unable to hold this ER position.

Question 32

Rotator Cuff tears
Physical examination

Subscapularis

Answer 32

Suspicion of IR weakness involving the subscapularis muscle is typically generated during the initial strength survey via resisted IR stress tests at both 0 and 90 degrees of GH abduction. In addition, patients may also exhibit increased ER capacity due to the decreased resting tension of the subscapularis muscle.

Belly-Press test: A positive test occurs when the affected elbow falls posteriorly due to the recruitment of ancillary muscles to compensate for the weakened subscapularis.

Lift-Off test: The test is begun by having the patient place the dorsal aspect of the hand on the lumbar spine. The examiner then passively lifts the hand away from the lumbar spine and asks the patient to hold this position. Inability to hold this position indicates subscapularis weakness.

Bear-Hug test: The bear hug test is though to cause near maximal activation of the subscapularis muscle.
In the most common version of the test, the patient first places the palm of the ipsilateral hand over the contralateral AC joint. With the tip of the elbow pointed directly forward, the patient is then instructed to push down onto the top of the shoulder without allowing the elbow to fall inferiorly. A positive test occurs when the patient is unable to maintain the elbow in a horizontal plane.

Question 33

Long Head of Biceps

Tendonitis, tearing and rupture

Pathogenesis

Answer 33

LHB tendonitis can occur as a result of impingement under the coracoacromial arch, subluxation out of the bicipital groove, or attrition as a result of degeneration.

Inflammation of the LHB tendon most often occurs secondarily as a result of surrounding pathologies such as impingement syndrome, pulley lesions, and/or degenerative rotator cuff tears.
Primary LHB tendonitis in which there is isolated inflammation with no apparent cause, is not uncommon in clinical practice. It is important to remember that because the LHB tendon is encased with synovium inflammation within the shoulder may track proximally into the biceps-labral complex or distally into the bicipital groove.
Subacromial impingement is the most common mechanism by which LHB tendonitis occurs, especially in older patients. Subcoracoid impingement can also lead to injury involving the LHB tendon and the BRP. Weak rotator cuff and periscapular musculature potentially allow increased translation of the HH, narrowing the space available for the subacromial or subcoracoid contents to pass thus allowing impingement of these structures between the greater tuberosity and the undersurface of the acromion or between the lesser tuberosity and the coracoid.

In patients with subacromial impingement, LHB tendonitis almost always occurs simultaneously since the LHB is subject to the same mechanical wear from the coracoacromial arch. In addition, because the LHB tendon is encased in an outward-facing synovial membrane extending from the GH joint, any inflammatory process within the joint can thus involve the LHB tendon, producing painful inflammation and tenosynovitis.

The acute stage of LHB tendonitis is characterised by significant anterior shoulder pain localised within the bicipital groove. The LHB tendon will swell and sometimes develop partial-thickness tearing at points of maximal wear. Later, the tendon further degenerates and may form adhesions with surrounding structures such as the bicipital sheath and rotator interval structures.

Question 34

Long Head of Biceps

Tendonitis, tearing and rupture

Physical Examination

Answer 34

Palpation: It is most important to realise that the bicipital groove faces directly anteriorly when the humerus is slightly internally rotated and tenderness with palpation of the groove will typically move laterally as the humerus is externally rotated.

Speeds test: The affected arm is placed in a position of 90 degrees forward flexion with the elbow extended and the palm supinated. From this position, the examiner applies a downward force to the forearm while the patient resists. Pain localised to the area of the bicipital groove is a positive test and may indicate the presence of bicipital tendonitis or partial tearing.

Yergason test: the affected arm is placed at the side with the elbow flexed 90 degrees. In patients with bicipital tendonitis or partial tearing, resisted supination of the forearm should produce pain over the anterior aspect of the shoulder localised to the bicipital groove.

Lift-off test: testing for RC function, especially that of the subscapularis can also provide clues regarding the status of the proximal LHB tendon as it passes through the bicipital groove. Tearing of the subscapularis may also involve tearing of the bicipital sheath and the LHB tendon itself.

Question 35

Long Head of Biceps tendon instability

Pathogenesis

Answer 35

Instability of the LHB tendon is most often associated with tearing of the subscapularis tendon, corcohumeral ligament and the SGHL, all of which are components of the BRP.
Most episodes of instability occur with the LHB translating medially over the lesser tuberosity.

Currently, there is insufficient data to suggest a specific pathomechanism responsible for the development of pulley lesions.

Question 36

Long Head of Biceps tendon instability

Physical Examination

Answer 36

Typically, the clinician will palpate the bicipital groove while simultaneously internally and externally rotating the humerus. Painful clicking or popping occurs as the LHB tendon translate over the lesser tuberosity.

Arm wrestler test: in the standard arm wrestling position, patient is asked to flex the elbow and supinate the forearm against resistance. A positive test occurs when pain or other mechanical symptoms are reproduced as the LHB tendon subluxes out of the bicipital groove.

Question 37

SLAP tears

Pathogenesis

Answer 37

Investigators most commonly cite forceful traction loads, forceful compression loads, and overhead sporting activities as the most common causes of SLAP tears.

Question 38

SLAP tears

Physical examination

Answer 38

The physical diagnosis of SLAP tears is one of the most challenging aspects of the shoulder examination.

However, it is now well recognised that sudden compression (eg FOOSH) or traction loads (eg shoulder dislocation or sudden inferiorly directed traction) are probably the most common etiologies of SLAP tears in the general population.

Crank test: The humerus is elevated above the horizontal plane with the elbow flexed to approximately 20 degrees. The examiner applies axial load though the humerus towards the glenoid while simultaneously internally and externally rotating the humerus. Reproduction of patient’s symptoms is considered a positive test.

Question 39

Classification of instability

Answer 39

Instability is typically described according to severity (microinstability, subluxation or dislocation), direction and chronicity.
Thomas and Matsen categorically divided those with instability into 2 distinct groups.
1. TUBS = Traumatic Unilateral instability with Bankart lesion and generally requires Surgery
2. AMBRI = Atraumatic, multidirectionaly instability which is typically Bilateral, responds to Physiotherapy and sometimes require Inferior capsular plication

Question 40

Pathoanatomic Features of Traumatic instability

Capsular Distention

Answer 40

The IGHL complex is the most important static restraint that prevents abnormal AP HH translation.
Once the microstructure of the ligament has been damaged via plastic deformation, a return to its previous shape and function is unlikely in most cases.

Question 41

Pathoanatomic Features of Traumatic instability

Bankart Lesions

Answer 41

Detachment of the anteroinferior glenoid labrum (Bankart lesion) is thought to occur in up to 90% of cases of traumatic anterior instability. Despite its near-universal presence in cases of traumatic instability, soft tissue Bankart lesion alone are not a frequent cause of recurrent instability. Rather, the underlying cause is most often multifactorial with particular focus on redundancy and plastic deformation of the IGHL complex.

Question 42

Pathoanatomic Features of Traumatic instability

ALPSA lesions

Answer 42

the Anterior labral periosteal sleeve avulsion lesion is an entity similar to that of the Bankart lesion; however, in this case, the periosteum along the anterior glenoid neck elevates from the underlying bone in a sleeve like pattern along with the IGHL-labrum complex.

Question 43

Pathoanatomic Features of Traumatic instability

SLAP tears

Answer 43

Superior labral anterior posterior tears are more common in overhead athletes probably as a result of the peel-back mechanism. The deceleration phase of the throwing motion may also produce extraphysiologic eccentric loads on the biceps anchor that can result in tearing or rupture.
More recent evidence suggests that posterosuperior migration of the HH in overhead athletes as a result of posterior capsular contracture may produce a greater degree of anterior translation that can easily be perceived as clinical laxity.

SLAP lesions that extend into the MGHL can also produce increased anterior humeral head translation.

Question 44

Pathoanatomic Features of Traumatic instability

HAGL lesions

Answer 44

The humeral avulsion of the GH ligament lesion occurs when the insertion of the IGHL complex avulses or otherwise separates from the humeral neck. Although its incidence is relatively low, this injury most commonly occurs after a 1st time anterior shoulder dislocation.
When combined with a Bankart lesion, the anterior band of the IGHL complex is referred to as floating segment.

Question 45

Pathoanatomic Features of Traumatic instability

Bony bankart lesions

Answer 45

Anterior shoulder dislocations can also create fractures of the anteroinferior glenoid rim. Loss of bone from the anterior glenoid from any cause decreases glenoid concavity and increases the potential for recurrent dislocations. In general, as the size of the lesion increases, GH stability decreases.

Question 46

Pathoanatomic Features of Traumatic instability

Attritional Glenoid bone loss

Answer 46

Erosion of the anteroinferior glenoid rim as a result of repeated dislocations is another cause for glenoid bone loss. These patients must rely on soft-tissue constraints to maintain anterior stability; however, these restraints are insufficient due to the capsuloligamentous stretching from previous anterior dislocations.
Bony reconstruction of the anterior glenoid is typically indicated which may involve iliac crest bone grafting the Latarjet procedure

Question 47

Pathoanatomic Features of Traumatic instability

Hill-Sachs lesions

Answer 47

The Hill-sacks lesion is characterised by an impression fracture of the posterosuperior aspect of the humeral head. These fractures can occur as a result of anterior dislocation when the soft bone of the posterosuperior HH impacts the much harder bone of the anteroinferior glenoid rim.
Although most lesions are small and generally do not affect GH stability, other larger lesions can cause recurrent dislocations especially in positions of 90 degrees of abduction and ER where the HH defect can engage the glenoid rim

Question 48

Pathoanatomic Features of Traumatic instability

Glenoid version

Answer 48

Glenoid version, especially retroversion, has been cited as an uncommon, but potential contributory factor involved in recurrent shoulder instability due to the absence of an effective glenoid arc.

Question 49

Pathoanatomic Features of Atraumatic instability

Answer 49

The cumulative effects of ADL and/or sporting activities can lead to joint damage and may lead to unilateral or bilateral instability without an apparent cause. However, some degree of genetic predisposition is implied when patients present with atraumatic bilateral shoulder instability.
for eg, studies have demonstrated increased elastin content in both the skin and capsular tissue of many patients with MDI in addition to increased capsular volume. These findings suggest that undiagnosed Ehlers-Danlos syndrome or multiligamentous laxity may be a substantial contributing factor involved in the development of instability in many of these patients.

Question 50

Glenohumeral Instability

Laxity testing

Answer 50

Drawer signs: Drawer signs can used to assess anterior or posterior humeral head translation as long as the patient remains in a relaxed state throughout the maneuver.
Although the original developers of this maneuver recommended that the arm be placed between 80 and 120 degrees of abduction, it is preferred to place the humerus in the approximate “loose pack” position to
1. minimise the effects of proprioceptive muscle contraction (generated by increased capsular tension)
2. to prevent scapular motion during testing
3. to more accurately assess true humeral head translation
The GH resting position is approximately between 55-70 degrees of abduction within the scapular plane with the neutral rotation.
A anterior or posterior force is applied to the shoulder and the amount of translation is estimated.

Load-and-shift test: With the patient sitting, the examiner places one hand over the top of the shoulder to stabilise the scapula while the other hand is placed over the proximal humerus. The examiner then applies gentle pressure to the proximal humerus in the direction of the glenoid fossa, thus ‘loading’ the joint. The humeral head is then grasped with the examiner’s hand. Anterior or posteriorly directed force is applied to induce translation of HH anteriorly or posteriorly.

Sulcus sign: This test has been utilised as a measure of inferior GH instability. The test is typically performed with the patient in sitting position. The examiner grasps the arm just above the elbow and applies gentle inferior traction to the GH joint. Each shoulder should also be tested individually with the humerus is maximum ER to evaluate laxity of the rotator interval structures.

Question 51

Glenohumeral Instability

Anterior instability

Answer 51

Drawer signs: A positive test was defined as either increased anterior HH translation as detected by the examiner or when the patient experienced feelings of apprehension during the maneuver. It should be remembered that asymmetric laxity measurements do not always indicate instability

Anterior Apprehension sign:

Question 52

Acromioclavicular Joint

Instability

Answer 52

Patients with acute AC joint injuries will complain of pain at the top of the shoulder following a significant impact-type injury to the lateral shoulder. Inspection of shoulder usually reveals swelling surrounding the area of the AC joint.
In cases of higher-grade injuries, an obvious step-off deformity may be present. Clinical should assess for concomitant clavicle fracture by palpating the entire length of the clavicle, beginning at the SC joint and moving towards the AC joint.

Type I injuries: patients typically present with mild to moderate pain and swelling over the AC joint following a traumatic injury; However, there are no visible or palpable deformities of the AC joint on clinical examination. These injuries represent a sprain of the capsuloligamentous structures without disruption of any associated structural ligaments.

Type II injuries: characterised by moderate to severe pain over the AC joint which usually increases when shoulder motion is initiated. Palpation of the AC joint often reveals moderate swelling and slight superior migration of the distal clavicle relative to acromion. Horizontal instability, which can be detected by manually moving the clavicle in anterior-posterior direction may be present in some type 2 injuries.
In type 2 injuries, the AC capsuloligamentous structures are torn which allows the clavicle to migrate suuperiorly; however, the CC ligaments remain intact.

Type III injuries: Patients usually present in moderate to severe pain with the arm in an adducted position and the weight of the arm supported to provide pain relief. The joint to tender to palpation and an obvious deformity is usually present which represents significant superior displacement of the distal clavicle. Manipulation of the clavicle would reveal both horizontal and vertical instability although significant guarding is usually present in the clinical setting. Radiographically, the clavicle will appear superiorly displaced relative to the acromion by approximately 100% the width of the distal clavicle. This injury pattern requires complete disruption of both the AC joint capsule and the CC ligaments while the deltotrapezial fascia remain intact.
A shrug test has been described to differentiate type 3 and 5 injuries. In this test, reduction of the injured AC joint by having the patient shrug their shoulders indicates that the deltotrapezial fascia is intact. If shrugging does not reduce the joint, the deltotrapezial fascia has been ruptured which usually signifies a type 5 injury.

Type IV injuries: characterised by complete posterior dislocation of the distal clavicle which typically pierces or punctures the fascia of the trapezius muscle. Patients with type IV injuries often present with severe swelling and pain localised to an area posterior to the medial acromion. In some cases, the distal clavicle may also produce skin tenting posteriorly.
Although infrequent, type 4 AC joint injuries can occur in combination with an anterior dislocation of the medial clavicle at the SC joint, thus producing a ‘floating clavicle’.

Type V injuries: Patients with type 5 injuries present similarly to those with type 3 injuries; however, the degree of pain, swelling and deformity are markedly more severe. Disruption of the deltotrapezial fascia is a hall-mark for type 5 dislocations.

Type VI injuries: are inferior dislocations in which the distal clavicle may end up in the subacromial space or beneath the coracoid process following a severe hyperabduction injury. Subcoracoid dislocations may also involve neurovascular symptoms given the proximity of the brachial plexus and surrounding vessels; however, symptoms usually resolve following joint reduction.

Question 53

Acromioclavicular Joint

Chronic AC joint injuries

Answer 53

Patients with chronic AC joint injuries who return for clinical evaluation should be thoroughly evaluated for possible sequelae such as scapular dyskinesia, RC disease and OA of the AC joint.

Question 54

Acromioclavicular Joint

Osteoarthritis

Answer 54

Symptoms related to a previous AC joint injury may reappear in the form of post-traumatic OA many years after the initial injury. It is presumed that nonoperative treatment of the initial injury allows repetitive micromotion and elevated shear stresses to occur across articular surfaces during shoulder motion until joint destruction leads to the development of pain. In addition, many patients with chronic AC joint dislocations display evidence of scapular dyskinesis which may increase the risk for other conditions such as RC impingement.

Question 55

Acromioclavicular Joint

Physical examination

Answer 55

Observation
Palpation
Cross-body adduction test
Active compression test (Obrien test)
Resisted arm extension test

Question 56

Sternoclavicular Joint

Acute SC joint dislocation

Answer 56

Due to the strength of its ligamentous stabilisers, subluxation or dislocation of the SC joint typically requires high-energy trauma. In fact, many patients who present with these injuries often sustain other, more dramatic injuries that require more immediate attention.
Instability of the SC joint is typically classified according to etiology (traumatic VS atraumatic), chronicity (acute VS chronic), direction and severity (sprain, subluxation or complete dislocation).

Physical examination: In most cases, patients with acute injuries to the SC joint typically complain of pain and swelling in the vicinity of the medial clavicle after a traumatic event.
When reduction of SC joint dislocation cannot be maintained, outpatient reconstruction of the SC joint may be needed to restore shoulder function, to maintain joint stability and to prevent the progression of post-traumatic OA.

Question 57

Sternoclavicular Joint

Osteoarthritis

Answer 57

Progressive articular cartilage degeneration of the SC joint most commonly occurs following an acute injury to surrounding capsuloligamentous, especially in cases that were initially treated nonoperatively.

Patients with degenerative conditions involving the SC joint will generally present with pain and swelling over the medial clavicle in the absence of a recent traumatic injury. The clinician should palpate the SC joint to detect crepitus or microinstability while the shoulder is placed through a ROM.

Question 58

Scapular Dyskinesis

Possible etiologies of scapular dyskinesis

Answer 58

Primary cause: primary causes of scapular dyskinesis are most commonly related to mechanical or neurogenic defects. Mechanical problems may be associated with a decrease in scapulothoracic space such as kyphoscoliosis, rib fracture callus or hypertrophic nonunion, shortened clavicle as a result of fracture malunion and enlarging soft-tissue or skeletal masses

Secondary cause: Many patients with shoulder pain develop compensatory periscapular muscle contraction (or relaxation) that functions to limit the pain associated with shoulder motion. This abnormal firing pattern produces disordered scapular motion that, in some cases, may exacerbate the inciting injury.
Currently, most forms of scapular dyskinesis are attributed to underlying defects related to soft-tissue structures around the shoulder. For eg: many overhead athletes display physical evidence of GIRD which generally is not considered pathologic unless there is an associated ROM loss relative to the total arc of motion. However, posterior capsular contractures are often found in these same athletes due to repeated throwing. These contractures essentially stiffen the posterior capsule such that GH adduction and IR causes the scapula to IR without input from the periscapular musculature.
Other common findings in patients with scapular dyskinesis are tightness of the short head of the biceps tendon and the pectoralis minor tendon which attaches to the coracoid process.

The most commonly encountered cascade of event occurs in the following sequence:

1. primary or secondary dyskinesis, which leads to
2. submaximal supraspinatus contraction, which leads to
3. gradual superior HH migration, which leads to
4. a gradual decrease in subacromial space
5. subacromial impingement and supraspinatus tears, which lead to
6. pain, which leads to
7. compensatory, asymmetric muscle firing patterns, which leads to
8. worsening of scapular malposition, dyskinesis, superior HH migration and so on

Question 59

Scapular Dyskinesis

Physical Examination

Answer 59

Scapular dyskinesis is usually diagnosed by simple palpation of the relevant scapular landmarks while also observing both scapulae during movement of the shoulder through the various motion planes.

The condition is most often characterised by prominence of the inferior angle and the medial scapular border(as a result of protraction in the resting position), early upward rotation of the scapula during arm elevation and/or early downward rotation of the scapula when lowering the arm back to the side.
Any abnormal scapular motion can compromise normal shoulder function by
1. reducing GH articular congruency
2. reducing acromiohumeral distance
3. increasing tension and strain across the AC joint capsule
4. decreasing the strength of RC contraction (which can also reduce GH stability)

Question 60

Scapular Dyskinesis with

Subacromial impingement and rotator cuff disease

Answer 60

Numerous studies have documented the presence of scapular dyskinesis in patients with subacromial impingement and rotator cuff tears. The precise abnormality in scapular motion that predisposes individuals to RC disease appears to vary significantly; However, theses studies have generally found decreased upward rotation, decreased posterior tilt, increased internal rotation of the scapula in patients with RC tears or impingement.
It is not known whether scapular dyskinesis is the cause or the result of RC disease.

Periscapular strengthening and proprioceptive training are typical rehabilitation options that are most often successful at providing symptomatic improvement

Question 61

Scapular Dyskinesis with

SLAP tears

Answer 61

SLAP tears are often seen in combination with scapular dyskinesis, especially in overhead athletes how demonstrate GIRD. This adaptation to repetitive throwing places the scapula in a position of decreased posterior tilt and increased internal rotation, thus increasing the strain across the biceps-labral complex via increased anterior capsular tension, extraphysiologic torsional strain and posterosuperior glenoid impingement.

Question 62

Scapular Dyskinesis with

Multidirectional instability

Answer 62

Inherited mulitligamentous laxity is most commonly implicated in patients with who present with evidence of multidirectional instability such as positive sulcus sign, apprehension sign and relocation sign.

Specifically, these patients often demonstrate decreased upward rotation, decreased posterior tilt, and increased internal rotation of the scapula during humeral elevation.
However, in contrast to many other shoulder conditions, the cause of scapular malposition and dyskinesis in patients with MDI is most likely secondary to increased capsular laxity.
Several studies concluded that both the GH ligaments and GH joint capsule have mechanoreceptors that respond to stretch by inducing a proprioceptive reflex mechanism that alters muscle firing patterns around the shoulder in order to optimise the position of the glenoid in 3D space.

Question 63

Neurovascular Disorders

Cervical radiculitis/radiculopathy

Answer 63

Many conditions related to the cervical spine can cause impingement of exiting nerve roots, leading to radiating pain towards the ipsilateral shoulder.

Physical examination

1. Cervical ROM
2. Spurlings test
3. Shoulder abduction test: resting the hand on top of the head. This maneuver is thought to increase the space available for the cervical nerve roots to exit the spinal cord, thus diminishing symptoms.
4. Cervical distraction test: This test is performed with the patient in the supine position. the examiner cradles the jaw and occiput and slightly flexes the neck to improve patient comfort. A distraction force is applied gently and gradually until significant resistance is felt. This maneuver is thought to increase the space available for exiting nerve roots. Relief of symptoms indicates a positive test and is indicative of cervical pathology.
5. Upper limb tension test

Question 64

Neurovascular Disorders

Thoracic Outlet syndrome

Answer 64

As the brachial plexus and subclavian vessels course towards the axilla and the upper arm, there are at least four areas of potential narrowing that can result from TOS.
The first potential site of compression occurs in patients with a congenital bony or fibrous extension of the transverse process of the 7th cervical vertebrae (cervical rib).
the second site of compression (most common) is between the anterior and middle scalene muscles.
Third site of narrowing is the costoclavicular space located between the middle 1/3 of the clavicle and the first rib. Impingement in this area primarily involves the subclavian artery and/or vein.
The fourth potential site of neurovascular compression is within the subcoracoid space in an area beneath the pectoralis minor muscle-tendon unit.

The numerous potential etiologies for TOS can be divided into static and dynamic causes. Static causes might include cervical ribs, fracture callus, fibrous bands, anomalous or fibrotic musculature, poor posture, pathologic lesions with significant mass effect such as a Pancoast tumor.
Reproduction of symptoms with scapulothoracic or GH motion typically indicates a dynamic cause which can occur within any of the 3 typically steotic areas.

Question 65

Neurovascular Disorders

Thoracic Outlet syndrome

Physical Examination

Answer 65

It is important to inspect the entire upper extremity, including the intrinsic muscles of the hand, for muscle atrophy, wasting or fasciculations since there may suggest the presence of a neuropathy or myelopathy. Hoffman’s sign is a useful test for the detection of cervical myelopathy.
Combined supraspinatus and infraspinatus atrophy can occur since innervation for both of these muscles is derived from the C5 nerve root (suprascapular nerve).

Adson’s test: The patient is asked to rotate the neck toward the affected shoulder, extend the neck and to take a deep breath while the examiner palpates the radial pulse. Where there is a decrease in pulse amplitude, the test is positive and indicates that the vascular component of the neurovascular bundle is being compressed within either the interscalene triangle or the costoclavicular triangle. Reproduction of parasthesias with this manuever can also occur, indicating compression of a neural structure.

Roos test:

Question 66

Peripheral Nerve entrapment around the shoulder

Brachial neuritis (also known as Pasonage-Turner sndrome, brachial neuropathy)

Answer 66

Unknown aetiology: has been associated with various factors proposed to cause the neuritis including trauma, infection, virus, heavy exercise, surgery, autoimmune conditions, vaccinations

Characteristically presents with 3 stages:

1. acute onset of severe shoulder pain which may both distally into the arm and proximally into the neck which may persist for days to weeks
2. Thereafter followed by resolution of pain and the onset of painless paresis, atrophy and sensory impairment of the shoulder girdle and/or upper limb due to involvement of the brachial plexus or its components of nerves
3. Followed by gradual recovery

Presentations can vary greatly dependent upon the predominant