Diagnosing shoulder pain
How should patients be examined?
What investigations should be carried out?
What are the red flags?
How should patients be examined?
What investigations should be carried out?
What are the red flags?
The prevalence of shoulder disorders has been reported to range from 7 to 36% of the population accounting for 1.2% of all GP?consultations.1 Shoulder pain has been said to be the second most common musculoskeletal complaint presenting in primary care. On average GPs are consulted approximately seven times each week for a complaint relating to the neck or upper extremity; three of these consultations will be for new complaints or new episodes. While current surgical management is complex, a significant proportion of cases can be managed non-surgically in general practice, by GPwSIs, with the aid of physiotherapy alone or in conjunction with steroid injection. An understanding of the anatomy, mechanics, aetiology and treatment of shoulder problems is therefore important to GPs.
The shoulder joint is an unstable ball and socket joint. The glenoid aspect of the scapula forms a shallow socket in which the humeral head rests. The lack of structural stability is necessary to enable the large range of motion at the shoulder joint which allows for all the prehensile actions of the upper limb and hand.
The stability is enhanced by the glenoid labrum. This is a thick band of fibrous tissue which is attached around the rim of the glenoid. This deepens the socket and thereby increases shoulder stability. The arch of the acromium above the shoulder and glenoid head also provides stability to the superior aspect.
The joint capsule contains thickened bands which strengthen the shoulder and act in a similar way to ligaments. The shoulder musculature contributes a large and significant degree of stability surrounding the posterior, superior and anterior aspect of the shoulder.
The muscles include (from posterior to anterior):
• the deltoid
• teres major
• teres minor
• long head of biceps.
These muscles coalesce near their insertion and form a muscular cuff around the head of the humerus. Above the humeral head there is a thick well defined conjoined tendon commonly referred to as the rotator cuff.
The function of the shoulder also depends upon the stability offered by the clavicle. This is joined to the manubrium and a stable part of the chest wall and to the scapula by the acromioclavicular joint.
It is often not fully appreciated that the function of the shoulder is dependent on the proper function of some structures at a distance from the shoulder itself, the clavicle, scapula, long head of biceps and the cervical spine.
The rotator cuff is principally made up of the teres minor, infraspinatus and supraspinatus muscles. It lies under the arch of the acromium above and anterior-lateral to the humeral head. It is here that the poorly vascularised tendon can become damaged and weakened by attrition or impingement against the overlying acromial arch of the scapula.
Shoulder mechanics are complex, involving simultaneous movement at three different joints (acromioclavicular, sternoclavicular and glenohumeral), between the scapula and the chest wall and also at the subacromial space.
The movement is a complex combination of muscle action. In movement the scapula needs to be stabilised against the chest wall by the scapular muscles including the clavicle, trapezius, serratus anterior and the rhomboids. The humeral head needs to be stabilised in the glenoid. The structural stability of the glenohumeral joint depends on the labrum being structurally sound. In addition, the stabilising effect of the isometric contraction of all the muscles around the shoulder provides stability for movement and strength in the hand and forearm. Without the shoulder stability to stabilise the joint and position the humerus no activity, strength or fine movement of the hand and forearm would be possible.
In many shoulder problems patients often feel pain around the medial aspect of the scapula in the area of the posterior chest wall. This pain is often from the rhomboid muscles which suffer strain when stiffness in the shoulder joint is compensated for by increased scapular excursion.
The cervical spine is a very important and often overlooked aspect of the shoulder and its problems. Many aspects have consequential effects on the shoulder joint:
If the cervical spine is stiff this may be due to muscular spasm in the para-cervical muscles. These muscles attach to the first rib or scapula therefore movement of the shoulder might also be painful and restricted.
If the cervical spine is arthritic this may restrict movement which may be compensated for by increased use of the shoulder joint and cause further problems.
Nerve root irritation
Cervical nerve root irritation may originate from a disc protrusion or nerve root canal narrowing. This may result in referred pain to the scapular or shoulder region or alternately radicular pain radiating into the upper arm. This commonly includes the C5 nerve root or the diaphragm or pericardium from the C5 component of the phrenic nerve.
If there is a cervical nerve root entrapment or neuropathy for any reason paralysis of certain shoulder muscles may occur with consequential dysfunction.
Peripheral nerve entrapment
Certain peripheral nerves may become damaged and result in shoulder problems. These include the:
• long thoracic nerve – scapular winging
• axilliary nerve – deltoid wasting
• suprascapular nerve – supraspinatus wasting.
The causes of shoulder pain are listed in table 1, attached. Making a diagnosis is a methodical process of identification, exclusion and confirmation by history, examination and additional investigations.
The nature and character of the onset of pain may be helpful in diagnosing shoulder joint problems. An injury, trauma or a repetitive movement may have precipitated pain eg serving while playing tennis, use of a keyboard or repetitive lifting. The site of the pain must be carefully identified and any change in the site or nature of the pain over time. Precipitating factors and relieving factors need to be identified. Specific questions must be targeted at excluding cervical, neurological or chest wall problems.
Careful questioning is important to establish the following:
• Length of complaint
• History of trauma
• Gradual or sudden onset
• Location of pain + any radiation
• What movement exacerbates the pain
• Is shoulder movement limited
• Any neck or back pain or stiffness
• Parasthesia/numbness in upper limb
• Pain at work or using keyboard
• Night pain
• Weight loss
• Loss of appetite
• Previous physiotherapy or injection
Many conditions have a characteristic age of onset. Impingement is very uncommon under the age of 35 and if present is likely to be due to instability, rather than degenerative.
0 - 30 years: Trauma; instability.
30 - 60 years: Subacromial impingement; adhesive capsulitis (frozen shoulder); acromio-clavicular joint degeneration.
>60 years: Impingement; rotator cuff tears; glenohumeral OA.
The site of the patient's pain gives many clues to the cause of the problem. Subacromial impingement or pain from rotator cuff tendonitis is typically felt in the lateral part of the upper arm and sometimes along the course of the supraspinatus tendon.
Pain from the acromioclavicular joint (ACJ) is often very localised to the ACJ at the anterior aspect of the shoulder.
Arthritis of the shoulder often presents with global pain in the joint which is worse following activity or at night.
A frozen shoulder may present with global pain in the whole arm, quadrant of the chest wall and lateral aspect of the neck. Pain felt to the medial aspect of the scapula with tenderness is often from the rhomboid muscles which become painful when the shoulder is stiff and more of the movement occurs at the scapulo-thoracic joint.
It is important to remember to assess the functional aspects of the shoulder problem and how the pain is impacting on the patient's life. Functional assessment will depend on the individual needs of the patient, ie the patient's occupation, sport, activities of daily living (ADLs).
In the elderly asking simple questions such as can you dress, wash or hang out the washing is helpful.
In younger patients the questions should relate more to their sporting, leisure and/or work activities. Such assessment can give you an idea of what the patient wants, or expects from treatment, and may help guide the eventual management and outcome criteria of the procedure.
Examination of the patient should start with the cervical spine. Examination should include forward and backward flexion, lateral flexion and rotation. Restrictions or pain and any areas of tenderness should be noted. Tenderness is commonly lateral to the cervical vertebral bodies rather than posteriorly.
The GP should stand behind the patient's affected shoulder while carrying out the examination. The examination should then proceed to the shoulder joint. Movement in flexion, lateral abduction and adduction across the chest should be assessed. The functional abilities in placing the hand up behind the back and behind the head should be recorded. Strength of resisted abduction (supraspinatus), external rotation (teres major) and elbow flexion (biceps long head) is also important.
Palpation should start with the trapezius, and progress around the shoulder. This includes the rhomboids infraspinatus, supraspinatus of the scapula before examination around the posterior aspect of the rotator cuff and humeral head, progressing to the lateral rotator cuff and anterior aspect of the glenoid. Finally, palpation of the acromio-clavicular joint and long head of biceps to the anterior aspect of the shoulder need special attention.
There are numerous tests for specific muscle function see below. Specific tests for shoulder pathology are listed in table 2, above.
• Muscle wasting (deltoid, supra/infraspinatus)
• ‘Squaring' of shoulder
Feel for tenderness, warmth, crepitus in the:
• Sternoclavicular joint
• Acromioclavicular joint.
• Clavicle, acromion, coracoid
• Internal/external rotation
• Describe the painful arc
Commonly radiographs are still used for the initial assessment of the shoulder. However for these to be diagnostic specific views need to be requested, see table 3, left.
However shoulder MRI is the investigation of choice and will provide the information necessary for surgical decisions. Once again on any request form the provisional diagnosis should be identified so the radiologist can determine the correct MRI sequences and planes of imaging. The information needed by a surgeon for a rotator cuff problem includes:
• the integrity and position of the rotator cuff
• the presence of fluid in the subacromial bursa
• the presence of any osteophytes under the ACJ
• the integrity of the long head of biceps
• for a patient with instability the information also includes: the integrity of the glenoid labrum and the presence of a Hill-Sacks defect in the femoral head
• the sensitivity of an MRI for rotator cuff tears is 92% and the specificity is 88 – 100%
MRI arthrography can be helpful in evaluating labral lesions, and may help to diagnose instability problems. CT scan can be used to obtain better imaging of bony structures. Ultrasonography is used in assessing rotator cuff tears, especially if full thickness. The accuracy of ultrasound is less than that of MRI and is reported as between 65 and 96%. Ultrasound is very operator dependent and it is more difficult for the surgeon to interpret the scan at a later stage. However it is much less expensive than MRI and can be used when MRI is contraindicated eg if the patient has claustrophobia, a pacemaker, metallic fragments or clips.
GPs may also want to order the following blood tests: FBC combined with an ESR or CRP analysis of inflammatory markers, to rule out anaemia of chronic disease, polymyalgia or rheumatoid arthritis. If infection is suspected, the patient should be referred to the local orthopaedic on-call team for specialist opinion on inflammatory markers. Other Investigations are best organised via MATS or the orthopaedic team.
There is a link between diabetes and frozen shoulder, so blood glucose may need to be measured. Diabetic frozen shoulders tend to be more resistant than idiopathic frozen shoulders, therefore many surgeons will treat them more aggressively.
Common conditions of the shoulder
Rotator cuff tendonitis
Problems with the rotator cuff can cause several painful conditions, and are one of the most common causes of shoulder pain presenting in primary care.
Also known as swimmer's shoulder, rotator cuff tendonitis is an inflammation of the tendons around the shoulder. It can occur in sports requiring the arm to be moved over the head repeatedly as in tennis, swimming, and lifting weights. Chronic inflammation or injury can cause the tendons of the rotator cuff to tear.
The symptoms of tendonitis are:
• Pain associated with arm movement
• Pain in the shoulder at night (especially when lying on the affected shoulder)
• Weakness with raising the arm above the head or
• Pain with overhead activities (brushing hair, reaching for objects on shelves, etc).
Clinical examination will reveal pain (+/- weakness) of the affected tendon and the patient will have a painful arc in abduction. Plain radiographs may reveal subacromial sclerosis and narrowing of the subacromial space, but they may be unremarkable.
• Rest from the activities that caused the problem and from activities that cause pain
• NSAIDs to help reduce inflammation and pain
• Physical therapy to strengthen the muscles of the rotator cuff should be started
• Steroid injection - may reduce pain and inflammation enough to allow effective therapy
• Surgery (if symptoms persist despite conservative therapy) may be necessary. Arthroscopic surgery can remove bone spurs and inflamed tissue around the shoulder.
Rotator cuff tear
Rotator cuff tear is a common cause of pain and disability in adults. Most tears occur in the supraspinatus muscle, but other parts of the cuff may be involved. The rotator cuff can be torn as a result of a single traumatic injury, or from chronic repetitive overuse. As with tendonitis, patients at particular risk are those who engage in repetitive overhead activities.
Symptoms are similar to those of tendinopathy, with pain and weakness of the affected tendon. If the tear is acute, a snapping sensation may be felt. The pain is classically described over the acromium, radiating down the lateral aspect of the arm. On examination there will be pain on abduction or when lowering the arm from a fully raised position, weakness of the involved tendon which may or may not be associated with muscle wasting. Plain films are usually normal, but may show a subacromial spur, subacromial sclerosis or narrowing of the subacromial space. An MRI may be useful in aiding the diagnosis.
Treatment of a tear varies depending on the underlying cause. Repair is considered for acute tears in young, fit individuals. It is unlikely to be of benefit in chronic tears. For pain secondary to rotator cuff disease, subacromial steroid injection has been demonstrated to have a small benefit over placebo in some trials.2 A subacromial decompression may help to manage pain, but will not improve muscle strength.
Frozen shoulder, also called adhesive capsulitis, is caused by adhesions forming around the shoulder joint. Three phases are classically described:
Freezing phase: Main symptom is pain, but patient may notice some decrease in their range of movement (ROM).
Frozen phase: Pain still present at extremes of motion, but main complaint is decreased ROM
Thawing phase: Resolution (usually painless at this stage)
Frozen shoulder will resolve spontaneously but may take up to two years to resolve. Intervention is warranted in any patient whose quality of life is significantly reduced through pain or loss of function. Frozen shoulder is common in patients with diabetes, and is often more resistant to conservative measures.3 Examination will reveal a marked loss of external rotation and a painful ROM of the affected shoulder.
Management may be conservative or surgical, often patients will be satisfied that their symptoms will resolve and no further intervention is necessary. The decision to treat should be based on the impact that symptoms have on their quality of life. In a patient who can cope with day-to-day activities, physiotherapy, NSAIDs and steroid injection may be all that is needed.2 In patients who are unable to cope options involve a manipulation under anaesthetic or an arthroscopic capsular release (the latter is usually preferred for patients with diabetes.)4
Remember that patients with frozen shoulder often describe a minor episode of trauma prior to the onset of their symptoms and that frozen shoulder is a clinical diagnosis based on the history and loss of external rotation.
It has been suggested that blood tests, radiology and further investigations of shoulder problems are generally only necessary if there are 'red flag' symptoms/signs.5
Red flag symptoms/signs
• History of malignancy or symptoms/signs consistent with neoplasia, eg weight loss, deformity, mass or swelling, abdominal discomfort/swelling
• Overlying skin erythema may suggest tumour or infection
• Symptoms/signs of systemic illness: ask specifically about symptoms that may indicate polymyalgia rheumatica/giant cell arteritis
• Fever can suggest malignancy or infection
• History of trauma or recent convulsion/electric shock may suggest an unreduced dislocation
• Change in shoulder contour with loss of rotation suggests dislocation
• Trauma with acute disabling pain and positive drop arm test suggests an acute rotator cuff tear
• The presence of a significant sensory or motor deficit suggests a neurological lesion
Patients with the following problems should be referred to an orthopaedic surgeon:
• An acute bony injury
• Pain and persistent disability despite conservative measures (for at least 6 months)
• Diagnostic uncertainty
• Acute rotator cuff tear due to trauma in younger patients
• Red flags
For most other conditions a course of conservative management is advisable before a referral is made. This may involve physiotherapy, analgesia, lifestyle modifications and possibly steroid injections.
Referrals can be made either direct to a shoulder surgeon, or via a musculoskeletal assessment service (MATS). The MATS team are able to evaluate patients further, organise necessary investigations, start treatment and refer to the orthopaedic team if necessary. If an initial steroid injection is indicated and the referring GP in unhappy about doing this in the surgery then a referral to the MATS team for injection may be the most appropriate management. This is a good starting point for most referrals.
Non surgical management
The mainstay of management is analgesia, physiotherapy, activity modification and steroid injections. Most often, (certainly in the elderly) conservative measures are effective.6
Most patients with shoulder pathology should be managed conservatively in the first instance. A trial of simple analgesia (paracetamol, NSAIDs) and rest should be carried out. If this gives no improvement referral to physiotherapy may be indicated.
A Cochrane review found that physiotherapy is effective for some specific shoulder disorders.1
Physiotherapy has particular benefit in treating muscle imbalance around the shoulder, but is also useful in frozen shoulder, impingement, multidirectional instability and as part of a postoperative rehabilitation programme. It should primarily be used with a view either to increase the ROM of a patient's shoulder, or to strengthen the muscles surrounding it.
In conjunction with physiotherapy, steroid injections may aid in relieving pain and helping to improve function. Steroid and local anaesthetic can be injected into the glenohumeral joint, acromioclavicular joint or the subacromial space all with varying effects. The efficacy of a shoulder injection depends on pathology, patient selection, previous injections and accuracy of injection. Whether an injection works or not may also provide diagnostic clues, for example, pain caused by subacromial impingement usually responds well to a subacromial injection.
It is however, important to remember that patients should not be offered more than three injections per joint per year.Useful websites
Van der Windt DA et al. Shoulder disorders in general practice: prognostic indicators of outcome. Br J Gen Pract 1996; 46: 519-23.
Speed C, Hazleman B; Shoulder pain. Clin Evid 2004; (12): 1735-54
Copeland; Operative shoulder surgery. Churchill Livingstone, 1995
Rockwood and Matsen; The Shoulder, second edition. WB Saunders Company 1998
Dr James Barnes
MBChB MRCS DipSICOT
Orthopaedic SPR, Musgrove Park Hospital, Taunton
Mr Alan Dunkley
MBBS FRCS FRCS(Orth)
Consultant Orthopaedic Surgeon, Musgrove Park Hospital, Taunton
Mr David P Johnson
MD MBChB FRCS FRCS(Orth)
Consultant Orthopaedic Surgeon, Spire Hospital Bristol