Shoulder Flashcards
Shoulder joint
The shoulder ,or gleno‐humeral, joint is a ball and socket synovial joint formed by the humeral head and the scapular glenoid.
shape of the glenohumeral joint and the complex interplay between bony anatomy and the supporting muscles affords a wide range of movement.
Due to the lack of inherent bony stability, the shoulder joint is dependent on the surrounding musculature for stability with the rotator cuff muscles providing an essential role.
shoulder girdle
shoulder girdle is formed by the scapula, the clavicle, the proximal humerus and the supporting muscles including the deltoid and the muscles of the rotator cuff.
rotator cuff is formed by four muscles :
-Supraapinatus
-Infraspinatus
-Teres Minor
-Subscapularis
what do the Supraapinatus, Infraspinatus & Teres Minor do
attach to the greater tuberosity.
Supraspinatus is responsible for initiation of abduction whilst infraspinatus and teres minor are external rotators.
what do the Subscapularis do
attaches to the lesser tuberosity and is the principal internal rotator.
rotator cuff muscles function
Collectively the rotator cuff muscles serve the crucial function of pulling the humeral head into the glenoid to provide a stable fulcrum for the powerful deltoid muscle to abduct the arm.
The rotator cuff muscles are under significant repeated stress and acute or degenerate tendon tears can occur which can cause pain and disability.
Furthermore due to altered shoulder biomechanics, chronic rotator cuff insufficiency can lead to glenohumeral OA.
The shoulder can also be subject to primary OA of the glenohumeral and acromioclavicular joints and other soft tissue disorders.
Impingement syndrome
a syndrome where the tendons of the rotator cuff (predominantly supraspinatus) are compressed in the tight subacromial space during movement producing pain.
Typically the patient has a painful arc between around 60 to 120 degrees of abduction (these values are variable) as an inflamed area of supraspinatus tendon passes though the subacromial space.
Impingement syndrome causes
-Tendonitis Subacromial bursitis
-Acromioclavicular OA with inferior osteophyte
-A hooked acromion Rotator cuff tear
Impingement syndrome symptoms
Pain from impingement characteristically radiates to the deltoid and upper arm.
Tenderness may be felt below the lateral edge of the acromion.
Impingement syndrome investigation
Hawkins-Kennedy test (internally rotating the flexed shoulder) recreates the patient’s pain.
Cervical radiculopathy should be excluded from history and examination.
Impingement syndrome treatment
conservative in the first instance with the majority of cases settling with NSAIDs, analgesics, physiotherapy and subacromial injection of steroid.
Up to 3 subacromial injections may be required.
Cases which do not improve with these interventions may benefit from subacromial decompression surgery to create more space for the tendon to pass through.
This procedure can be done as an open procedure (through an incision large enough to visualise the subacromial space) or with minimally invasive arthroscopic techniques (when small instruments and a keyhole camera are inserted into the subacromial space to perform the surgery) .
Rotator cuff tears
The tendons of the rotator cuff can tear with minimal or no trauma as a consequence of degenerate changes in the tendons.
Rotator cuff tears symptoms & risk factors
A classic history is of a sudden jerk (eg holding a rail on a bus which suddenly stops) in a patient >40 years of age, with subsequent pain and weakness.
At least 20% of over 60 year olds have asymptomatic cuff tears due to tendon degeneration.
In theory, rotator cuff tendons can tear in young patients due to a significant injury (including shoulder dislocation) although this is very uncommon.
Rotator cuff tears different types of tears & investigation
Tears can be partial or full thickness and usually involve suprapinatus.
Large tears can extend into subscapularis and infraspinatus. Weakness of initiation of abduction (supraspinatus), internal rotation (subscapularis) or external rotation (infraspinatus) may be detected and wasting of supraspinatus may be seen.
Tears are confirmed on Ultrasound or MRI.
Rotator cuff tear treatment
Surgery: Rotator cuff repair (open or arthroscopic) with subacromial decompression can be performed in an attempt to improve/maintain strength and to prevent subsequent arthritis from chronic cuff deficiency.
However, the tendon is usually diseased and failure of repair occurs in around a third of cases. Very large tears may be irrepairable and the tendon may be retracted too far.
Non-operative: Many patients do well with physiotherapy to strengthen up the remaining cuff muscles which can compensate for the loss of supraspinatus.
Subacromial injection may help symptoms.
Overall the long term results of rotator cuff surgery are not fully known.
Adhesive capsulitis (frozen shoulder)
This is a disorder characterized by progressive pain and stiffness of the shoulder in patients between 40 and 60, resolving after around 18‐24 months.
Adhesive capsulitis (frozen shoulder) aetiology/ causes
aetiology is unclear.
sometimes a history of an innocuous triggering injury but often not. It may also occur after shoulder surgery.
diabetics are particularly prone and the condition has also been associated with hypercholesterolaemia and Dupuytren’s disease (similar thickened fascial tissue is found histologically).
the capsule and glenohumeral ligaments become inflamed then thicken and contract.
Adhesive capsulitis (frozen shoulder) symptoms
complain of pain, which will subside (after around 2‐9 months) as stiffness increases (for around 4‐12 months) and then the stiffness gradually “thaws” out over time, usually with good recovery of shoulder motion.
principal clinical sign is loss of external rotation (along with restriction of other movements) which can also occur in OA, however OA tends to affect older patients.
Adhesive capsulitis (frozen shoulder) treatment
majority of cases is non-operative with the aim of relieving pain and to prevent further stiffening while the condition resolves naturally.
Physiotherapy and analgesics help.
Intra‐articular (gleno‐humeral rather than subacromial) injections can help in the painful phase.
Once the pain has settled, if the patient cannot tolerate functional loss due to stiffness, recovery can be hastened by manipulation under anaesthetic (MUA which tears the capsule) or surgical capsular release (usually done arthroscopically) which divides the capsule leading to improved motion.
Acute calcific tendonitis
results in the acute onset of severe shoulder pain and is characterized by calcium deposition in the supraspinatus tendon which is seen on xray just proximal to the greater tuberosity.
Great relief of pain is achieved with subacromial steroid and local anaethetic injection.
condition is self‐limiting with pain easing as the calcification resorbs.
Instability of the shoulder
involves painful abnormal translational movement or subluxation and/or recurrent dislocation.
Two sub-types or patterns of instability:
Traumatic instability
Atraumatic instability
Traumatic instability
experience a traumatic anterior dislocation which after reduction may settle and the shoulder stabilizes with rest and a physiotherapy strengthening programme.
some shoulders do not stabilize and develop recurrent dislocations or subluxations, often with minimal force.
age at time of first dislocation predicts the likelihood of further dislocations with 80% re‐dislocation rate in under 20s and 20% re‐dislocation rate in under 20s and 20% re‐dislocation rate in over 30s.
recurrent dislocations, a Bankart repair (open or arthroscopic) can stabilize the shoulder by reattaching the labrum and capsule to the anterior glenoid which was torn off in the first dislocation.
Atraumatic instability
Patients with generalized ligamentous laxity (idiopathic, Ehlers‐Danlos, Marfan’s) can have pain from recurrent multidirectional (anterior, posterior or inferior) subluxations or dislocations.
Treatment is difficult as soft tissue procedures may not work.
