PAIN IN THE SHOULDER
The shoulder is a shallow joint with a large range of movements .The humeral head is held in place by the rotator cuff ,which is part of the joint capsule.
It comprises the tendons of infraspinatus and teres minor posteriorly ,supraspinatus superiorly and teres major and subscapularis anteriorly .The rotator cuff ( particularly supraspinatus ) prevents the humeral head blocking against the acromion during abduction , the deltoid pulls up and the supraspinatus pulls in to produce a turning moment and permit the greater tuberosity to glide under the acromion without impingement.
Pain in the shoulder can sometimes be due to problems in the neck.Although the term FROZEN SHOULDER is commonly used for any painful stiff shoulder ,true frozen shoulder ( adhesive capsulitis ) is uncommon .
A painful ,stiff shoulder can result from rotator cuff lesions and is also seen following hemiplegia ,chest or breast surgery or myocardial infarction.Painful shoulders may also be the initial presentation of Rhematoid arthritis ,less commonly a seronegative spondarthritis ,and of polymyalgia rheumatica in the elderly.
DIFFERENTIAL DIAGNOSIS OF SHOULDER PAIN
Rotator cuff tendonitis pain is worse in night ad radiates to the upper arm.
Painful shoulders produce secondary muscular neck pain.
Muscular neck pain ( also known as shoulder girdle pain ) does not radiate to the upper arm.
Cervical nerve root painis usually associated with pins and needles or neurological signsin the arm.
ROTATOR CUFF ( SUPRASPINATUS ) TENDONITIS
This is a common cause of painful resriction of the shoulder at all ages .It follow trauma in 30% of cases and is bilateral in under 5% .The pain radiates to the upper arm and is made worse by arm abduction and elevation ,which are often limited.The pain is often worse during the middle of the range of abduction , reducing as the arm is raised fully and the painful part of the tendon rotates through to the proximal side of the acromion - a so - called painful arc syndrome.When examined from behind ,the scapula rotates earlier during elevation.Passive elevation reduces impingement and is less painful .Severe pain virtually immobilizes the joint ,although some rotation is retained ( cf ,adhesive capsulitis ) .There is also painful spasm of the trapezius .X-rays are necessary only when rotator cuff tendonitis is persistent or the diagnosis is uncertain.
TREATMENT
Analgesics or Nonsteroidal anti inflammatory drugs may suffice ,but severe pain responds to an injection of crticosteroid .Patients should be warned that 10% will develop worse pain for 24-48 hours after injection .Severiy per cent improve over 5-20 days and mobilize the joint themselves.Physiotherapy helps persistent stiffness but further injections may be needed.
CALCIFIC TENDONITIS AND BURSITIS
Calcium pyrophosphate deposits in the tendon are visible on x-ray ,but they are not always symptomatic.The pathgenesis is unclear ,although the part of the tendon affected is likely to be affected by relative ischemia.The deposit is ususlly just proximal to the greater tuberosity.It may lead to acute or chronic recurrent shoulder pain and restriction of movement .A local corticosteroid injection may help and ultrasound treatment may help to resolve the calcification .Aspiration of the deposit under x-ray control may be required for persistent pain .Rarely arthroscopic removal is necessary.Shedding of crystals into the subacromial bursa causes severe pain and shoulder restriction.The shoulder feels hot and is swollen ,and an x-ray will show a diffuse opacity in the bursa.The differential diagnosis of calcific bursitis is gout ,pseudogout or septic arthritis.Aspiration and injection with corticisteroid can help.
TORN ROTATOR CUFF
This is caused by trauma in the young but also occurs spontaneously in the elderly and in rheumatoid arthritis ( RA).It prevents active abduction of the arm , but patients learn to initiate elevation using the unaffected arm.Once elevated ,the arm can be held in place by the deltoid muscle.In younger people ,the tear is repaired surgically but this is rarely possible in the elderly or in rheumatoid arthritis.Repeated trauma of the cuff between humerus and acromion/acromioclavicular joint causes osteophyte and cyst formation.
Shoulder impingement syndrome causes pain and crepitus on abduction and rotation.
ADHESIVE CAPSULITIS ( TRUE " FROZEN SHOULDER " )
This is uncommon .Severe shoulder pain is associated with complete loss of all shoulder movements,including rotation.High doses of Non steroidal anti inflammatory drugs ( NSAIDs ) and intra-articular injections of corticisteroids are helpful.Once the pain settles ,a manipulation under anaesthetic is advisable.When untreated ,it removes in 1-2 years.
