The bone which abuts a joint (epiphyseal bone) differs structurally from the shaft (metaphysis) (see Fig. 11.32). It is highly vascular and comprises a light framework of mineralized collagen enclosed in a thin coating of tougher, cortical bone. The ability of this structure to withstand pressure is low and it collapses and fractures when the normal intra-articular covering of hyaline cartilage is worn away as in osteoarthritis (OA; see p. 512). Loss of surface cartilage also leads to the abnormalities of bone growth and remodelling typical of OA (see p. 512).

Bone structure and physiology

Bone structure and physiology is discussed on page 549.

Hyaline cartilage

Hyaline cartilage forms the articular surface and is avascular. It relies on diffusion from synovial fluid for its nutrition. It is rich in type II collagen that forms a meshwork enclosing giant macromolecular aggregates of proteoglycan. These heterogeneous macromolecules comprise protein chains with side-chains of the carbohydrates keratan and chondroitin sulphate (aggrecans). These molecules have a negative charge and retain water in the structure by producing a dynamic tension between the retaining force of the collagen matrix and the expansive effect of osmotic pressure. Intermittent pressure from ‘loading’ of the joint is essential to normal cartilage function and encourages movement of water, minerals and nutrients between cartilage and synovial fluid. Chondrocytes secrete collagen and proteoglycans and are embedded in the cartilage. They migrate towards the joint surface along with the matrix they produce.

Ligaments and tendons

These structures stabilize joints. Ligaments are variably elastic and this contributes to the stiffness or laxity of joints (see p. 559). Tendons are inelastic and transmit muscle power to bones. The joint capsule is formed by intermeshing tendons and ligaments. The point where a tendon or ligament joins a bone is called an enthesis and may be the site of inflammation.

Skeletal muscle

This consists of bundles of myocytes containing actin and myosin molecules. These molecules interdigitate and form myofibrils which cause muscle contraction in a similar way to myocardial muscle (p. 671). Bundles of myofibrils (fasciculi) are covered by connective tissue, the perimysium, which merges with the epimysium (covering the muscle) and forms the tendon which attaches to the bone surface (enthesis).

Clinical approach to the patient

Taking a musculoskeletal history

The following questions are helpful in assessing the problem and making a diagnosis. A history can often lead to a diagnosis as pattern recognition is the key to diagnosis in rheumatic diseases.

Has there been recent trauma?

Pain

Where is it? Is it localized or generalized? The pattern of joint involvement is a useful clue to the diagnosis (e.g. distal interphalangeal joints in nodal osteoarthritis).

Is it arising from joints, the spine, muscles or bone, with local tenderness? Soft tissue lesions and inflamed joints are locally tender.

Could it be referred from another site? Joint pain is localized but may radiate distally – shoulder to upper arm; hip to thigh and knee.

Is it constant, intermittent or episodic? How severe is it – aching or agonizing?

Are there aggravating or precipitating factors? Is it made worse by activity and eased by rest (mechanical) or worse after rest (inflammatory).

Are there any associated neurological features? Numbness, pins and needles and/or loss of power suggest ‘nerve’ involvement. The distribution of symptoms is a useful clue to the nerve or nerve root affected.

Swelling

Is it of one joint, or of several? Look for symmetry or asymmetry, and/or a peripheral or proximal pattern. An acute monoarthritis may be due to trauma, gout (in a middle-aged male) or sepsis (fever or immunosuppression).

Is it constant or does it come in short-lived or longer episodes?

Is there associated inflammation (redness and warmth)?

Gender

Gout (see p. 530), reactive arthritis (p. 529) and ankylosing spondylitis (p. 527) are more common in men. Rheumatoid arthritis and other autoimmune rheumatic diseases are more common in women.

Age

Is the person young, middle-aged or older?

How old was the patient when the problem first started? Osteoarthritis (see p. 512) and polymyalgia rheumatica (p. 542) rarely affect the under-50s. Rheumatoid arthritis starts most commonly in women aged 30–50 years.

General health

Is there any associated ill-health or other worrying feature, such as weight loss or fever?

Are there other associated medical conditions that may be relevant? Psoriasis (see p. 1207) or inflammatory bowel disease is associated with spondyloarthritis (see p. 1004). Charcot’s joints (p. 547) are seen in diabetics.

Medication

Could a drug be a cause? Diuretics may precipitate gout in men and older women. Hormone replacement therapy or the oral contraceptive pill may precipitate systemic lupus erythematosus (SLE) (p. 535). Steroids can cause avascular necrosis. Some drugs cause a lupus-like syndrome (p. 535).

Race

Is this relevant? Sickle cell disease causes joint pain in young black Africans, but osteoporosis (see p. 552) is uncommon in older black Africans.

Past history

Have there been any similar episodes or is this the first? Are there any clues from previous medical conditions? Gout is recurrent; the episodes settle without treatment in 7–10 days. Acute episodes of palindromic rheumatism may predate the onset of rheumatoid arthritis (see p. 519).

Family history

Does anyone in the family have a similar problem or another related disorder?

Occupational history

What job does the patient do? This can be a factor in soft tissue problems and osteoarthritis (e.g. in heavy labourers and dancers). Work-related problems, particularly in those who use a keyboard, are becoming more common and are complained of more.

Psychosocial history

The biopsychosocial model of disease is highly relevant to many rheumatic disorders:

Has there been any recent major stress in family or working life? Could this be relevant? Stress rarely causes rheumatic disease but may precipitate a flare-up of inflammatory arthritis. It reduces a person’s ability to cope with pain or disability.

Has there been an injury for which a legal case for compensation is pending?

Extent of disability

The World Health Organization describes the impact of disease on an individual in terms of:

Impairment: any loss or abnormality of psychological or anatomical structure or function

Disability (activity limitation): any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being

Handicap (participation restriction): a disadvantage for an individual resulting from an impairment or disability that limits or prevents the fulfilment of a role that is normal for that individual.

The patient’s own perception of limitation must be taken into account during assessment, as well as the impact of physical causes due to disease. Subjective and objective assessments must be made. Quality of life (QoL) involves physical and psychosocial factors. The aim of treatment is to reduce or cure physical and/or psychological disease and to reduce the impact of any impairment or disability on the individual. A variety of different standard questionnaires is used to assess pain, disease impact and outcome (e.g. Health Assessment Questionnaire, HAQ; Arthritis Impact Measurement Scale, AIMS).

Examination of the joints

Always observe a patient, looking for disabilities, as he or she walks into the room and sits down. General and neurological examinations are often necessary. Guidelines for rapid examinations of the limbs and spine are shown in Practical Box 11.1.

Practical Box 11.1

Rapid examinations of the limb and spine

Rapid examination of the upper limbs

Raise arms sideways to the ears (abduction). Reach behind neck and back. Difficulties with these movements indicate a shoulder or rotator cuff problem.

Hold the arms forward, with elbows straight and fingers apart, palm up and palm down. Fixed flexion at the elbow indicates an elbow problem. Examine the hands for swelling, wasting and deformity.

Place the hands in the ‘prayer’ position with the elbows apart. Flexion deformities of the fingers may be due to arthritis, flexor tenosynovitis or skin disease. Painful restriction of the wrist limits the person’s ability to move the elbows out with the hands held together.

Make a tight fist. Difficulty with this indicates a loss of flexion or grip. Grip strength can be measured.

Rapid examination of the lower limbs

Ask the patient to walk a short distance away from and towards you, and to stand still. Look for abnormal posture or stance.

Ask the patient to stand on each leg. Severe hip disease causes the pelvis on the non-weight-bearing side to sag (positive Trendelenburg test).

Watch the patient stand and sit, looking for hip and/or knee problems.

Ask the patient to straighten and flex each knee.

Ask the patient to place each foot in turn on the opposite knee with the hip externally rotated. This tests for painful restriction of hip or knee. Abnormal hips or knees must be examined lying.

Move each ankle up and down. Examine the ankle joint and tendons, medial arch and toes whilst standing.

Rapid examination of the spine

Stand behind the patient.

Ask the patient to (a) bend forwards to touch the toes with straight knees, (b) extend backwards, (c) flex sideways, and (d) look over each shoulder, flexing and extending and sideflexing the neck. Observe abnormal spinal curves – scoliosis (lateral curve), kyphosis (forward bending) or lordosis (backward bending). A cervical and lumbar lordosis and a thoracic kyphosis are normal. Muscle spasm is worse whilst standing and bending. Leg length inequality leads to a scoliosis which decreases on sitting or lying (the lengths are measured lying).

Ask the patient to lie supine. Examine any restriction of straight-leg raising (see disc prolapse, below).

Ask the patient to lie prone. Examine for anterior thigh pain during a femoral stretch test (flexing knee whilst prone), which indicates a high lumbar disc problem.

Palpate the spine and buttocks for tender areas.

Examining an individual joint involves three stages: looking, feeling and moving (Table 11.1). A screening examination of the locomotor system, known by the acronym GALS (Global Assessment of the Locomotor System) has been devised. X-ray or ultrasound of the joint often forms an integral part of the examination.

Table 11.1 Examination of the joint

LOOK at the appearance of the joint	Swelling – could be bony, fluid or synovial
	Deformity – valgus, where the distal bone is deviated laterally (e.g. knock-knees or genu valgum)
	Varus where the distal bone is deviated medially (bow-legs or genu varum)
	Fixed flexion or hyperextension
	Rash – especially psoriasis
	Muscle wasting – easier to see in large muscles like the quadriceps
	Scars – from surgery or trauma
	Signs of inflammationSymmetry – are the right and left joints (e.g. hips, knees, any other paired joint) the same? If not which do you think is abnormal?
FEEL	Swelling – fluid swelling (effusion) usually represents increased synovial fluid in inflammatory arthritis, but can be due to blood or pus
	Synovial swelling is rubbery or boggy and usually occurs in inflammatory arthritis
	Bony swelling, such as Heberden’s nodes in the fingers is usually seen in osteoarthritis
	Warmth – a warm joint may be inflamed or infected
	Tenderness – may represent joint inflammation, but many people have chronic tenderness all over the body (e.g. in fibromyalgia)
MOVE	Active movement – is the range full and pain-free? Is the movement fluid? In the hands – can the patient perform fine movements? In the legs – can the patient walk properly?
	Compare movements on the right and left side – are they symmetrical?
	Is there crepitus when the joint is moved?
	If active movement is limited try passive movement. In a joint problem both will usually be affected. If it is a muscle or nerve problem passive movement may remain full.

Investigations

Investigations are unnecessary in many of the common musculoskeletal problems; the diagnosis is clear from the history and examination findings. Tests help to exclude another condition and to reassure the patient or their primary care physician.

Useful blood screening tests

Full blood count

– Haemoglobin. Normochromic, normocytic anaemia suggests chronic inflammatory and autoimmune diseases. Hypochromic, microcytic anaemia indicates iron deficiency, sometimes due to non-steroidal anti-inflammatory drug (NSAID) induced gastrointestinal bleeding.

– White cell count. Neutrophilia is seen in bacterial infection (e.g. septic arthritis). It also occurs with corticosteroid treatment. Lymphopenia occurs with viral illnesses or active systemic lupus erythematosus (SLE). Neutropenia may reflect drug-induced bone marrow suppression. Eosinophilia is seen in the Churg–Strauss syndrome (p. 847).

– Platelets. Raised platelets occur with any chronic inflammation. Thrombocytopenia is seen in drug-induced bone marrow suppression.

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). An increase of these reflects inflammation. Plasma viscosity is also raised in inflammatory disease.

Bone and liver biochemistry. A raised serum alkaline phosphatase may indicate liver or bone disease. A rise in liver enzymes is seen with drug-induced toxicity. For other investigations of bone, see page 550.

Other blood and urine tests

Protein electrophoretic strip (and/or immunofixation), serum free light chain testing and urinary Bence Jones protein – to exclude myeloma as a cause of a raised ESR.

Serum uric acid – for gout.

Antistreptolysin-O titre – in rheumatic fever.

Serum autoantibody studies

Rheumatoid factors (RFs) (see also p. 518). Rheumatoid factors are detected by enzyme linked immunoabsorbent assay (ELISA). RFs are antibodies (usually IgM, but also IgG or IgA) against the Fc portion of IgG. They are detected in 70% of people with rheumatoid arthritis (RA), but are not diagnostic. RFs are detected in many autoimmune rheumatic disorders (e.g. SLE), in chronic infections, and in asymptomatic older people (Table 11.2).

Anti-citrullinated peptide antibodies (ACPA). These antibodies are directed against citrullinated antigens, vimentin, fibrinogen, alpha enolase and type II collagen. They are measured by an ELISA technique and are present in up to 80% of people with RA. They have a high specificity for RA (90% with a sensitivity of 60%). They are helpful in early disease when the RF is negative to distinguish it from acute transient synovitis (see Box 11.6, p. 519). Positivity for RF and/or ACPA is associated with a worse prognosis and an increase in the likelihood of bony erosions in people with RA.

Antinuclear antibodies (ANAs). These are detected by indirect immunofluorescent staining of fresh-frozen sections of rat liver or kidney or Hep-2 cell lines. Different patterns reflect a variety of antigenic specificities that occur with different clinical pictures (see Box 11.16, p. 537). ANA is used as a screening test for systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) – a negative ANA makes either condition highly unlikely – but low titres occur in RA and chronic infections and in normal individuals, especially the elderly (Table 11.3).

Anti-double-stranded DNA (dsDNA) antibodies. These are usually detected by a precipitation test (Farr assay), by ELISA, or by an immunofluorescent test using Crithidia luciliae (which contains double-stranded DNA). Raised anti-dsDNA is highly specific for SLE and the levels usually rise and fall in parallel with disease activity so can be used to monitor the level of treatment required.

Anti-extractable nuclear antigen (ENA) antibodies (see Box 11.16, p. 537). These produce a speckled ANA fluorescent pattern, and can be identified by ELISA. The most commonly measured ENAs are:

– Anti-Ro and anti-La, which occur in Sjögren’s syndrome and SLE

– Anti-Sm, which is highly specific for SLE

– Anti-Jo-1, which is the commonest of the anti-tRNA synthetase enzymes that occur in some people with dermatomyositis or polymyositis

– Anti-topoisomerase I (anti-Scl 70), which is specific for SSc

– Anti RNA-polymerase I and III, which occur in SSc and are associated with pulmonary fibrosis.

Anti-neutrophil cytoplasmic antibodies (ANCAs) (see p. 544). These are predominantly IgG autoantibodies directed against the primary granules of neutrophil and macrophage lysosomes. They are strongly associated with small-vessel vasculitis. Two major clinically relevant ANCA patterns are recognized on immunofluorescence:

– Proteinase 3 (PR3-ANCA), also called cytoplasmic or cANCA, producing a granular immunofluorescence and seen in Wegener’s granulomatosis,

– Myeloperoxidase (MPO-ANCA), also called perinuclear or pANCA, producing a perinuclear stain and seen in microscopic polyarteritis (polyangiitis) and Churg–Strauss syndrome.

Antiphospholipid antibodies (see p. 538). These are detected in the antiphospholipid syndrome (see p. 538).

Immune complexes. Immune complexes are infrequently measured, largely because of variability between assays and difficulty in interpreting their meaning. Assays based on the polyethylene glycol precipitation method (PEG) or C1q binding are available commercially.

Complement. Low complement levels indicate consumption and suggest an active disease process in SLE.

Table 11.2 Conditions in which rheumatoid factor is found in the serum

Autoimmune rheumatic diseases	RF (IgM) %
Rheumatoid arthritis	70
Systemic lupus erythematosus	25
Sjögren’s syndrome	90
Systemic sclerosis	30
Polymyositis/dermatomyositis	50
Juvenile idiopathic arthritis	Variable
Viral infections	Hyperglobulinaemias
Hepatitis	Chronic liver disease
Infectious mononucleosis	Sarcoidosis
Cryoglobulinaemia
Chronic infections	Normal population
Tuberculosis	Elderly
Leprosy Infective endocarditis	Relatives of people with RA
Syphilis

Table 11.3 Conditions in which serum antinuclear antibodies are found

	(%)
Systemic lupus erythematosus	95
Systemic sclerosis	70
Sjögren’s syndrome	80
Polymyositis and dermatomyositis	40
Rheumatoid arthritis	30
Juvenile idiopathic arthritis	Variable
Other diseases
Autoimmune hepatitis	100
Drug-induced lupus	>95
Myasthenia gravis	50
Idiopathic pulmonary fibrosis	30
Diabetes mellitus	25
Infectious mononucleosis	5–10
Normal population	8

Joint aspiration

Examination of joint (or bursa) fluid is used mainly to diagnose septic, reactive or crystal arthritis. The appearance of the fluid is an indicator of the level of inflammation. The procedure is often undertaken in combination with injection of a corticosteroid. Aspiration alone is therapeutic in crystal arthritis (see Practical Box 11.2, p. 508).

Examination of synovial fluid

Aspiration and analysis of synovial fluid are always indicated when an infected or crystal induced arthritis is suspected, particularly a monoarthritis. Normal fluid is clear and straw coloured and contains <3000 WBC/mm³. Inflammatory fluid is cloudy and contains >3000 WBC/mm³. Septic fluid is opaque and less viscous and contains up to 75 000 WCC/mm³. There is much overlap.

Polarized light microscopy is performed for crystals.

Gout: negatively birefringent, needle-shaped crystals of sodium urate

Pyrophosphate arthropathy (pseudogout): rhomboidal, weakly positively birefringent crystals of calcium pyrophosphate.

Gram staining is essential if septic arthritis is suspected and may identify the organism immediately. Joint fluid should be cultured and antibiotic sensitivities requested.

Diagnostic imaging and visualization

X-rays can be diagnostic in certain conditions (e.g. established rheumatoid arthritis) and are the first investigation in many cases of trauma. X-rays can detect joint space narrowing, erosions in rheumatoid arthritis, calcification in soft tissue, new bone formation, e.g. osteophytes and decreased bone density (osteopenia) or increased bone density (osteosclerosis):

1. In acute low back pain (see p. 503), X-rays are indicated only if the pain is persistent, recurrent, associated with neurological symptoms or signs, or worse at night or associated with symptoms such as fever or weight loss.

2. Radiological changes are common in older people and may not indicate symptomatic osteoarthritis or spondylosis.

3. X-rays are of little diagnostic value in early inflammatory arthritis but are useful as a baseline from which to judge later change.

Ultrasound (US) is particularly useful for periarticular structures, soft tissue swellings and tendons and for detecting active synovitis in inflammatory arthritis. It is increasingly used to examine the shoulder and other structures during movement, e.g. shoulder impingement syndrome (see p. 500). Doppler US measures blood flow and hence inflammation. US is used to guide local injections.

Magnetic resonance imaging (MRI) shows bone changes and intra-articular structures in striking detail. Visualization of particular structures can be enhanced with different resonance sequences. T₁-weighted is used for anatomical detail, T₂-weighted for fluid detection and short tau inversion recovery (STIR) for the presence of bone marrow oedema. It is more sensitive than X-rays in the early detection of articular and periarticular disease. It is the investigation of choice for most spinal disorders but is inappropriate in uncomplicated mechanical low back pain. Gadolinium injection enhances inflamed tissue. MRI can also detect muscle changes, e.g. myositis.

Computerized axial tomography (CT) is useful for detecting changes in calcified structures but dose of irradiation is high.

Bone scintigraphy utilizes radionuclides, usually ^99mTc, and detects abnormal bone turnover and blood circulation and, although nonspecific, helps in detecting areas of inflammation, infection or malignancy. It is best used in combination with other anatomical imaging techniques.

DXA scanning uses very low doses of X-irradiation to measure bone density and is used in the screening and monitoring of osteoporosis.

Positron emission tomography (PET) scanning uses radionuclides, which decay by emission of positrons. ¹⁸F-Fluorodeoxyglucose uptake indicates areas of increased glucose metabolism. It is used to locate tumours and demonstrate large vessel vasculitis, e.g. Takayasu’s arteritis (see p. 789). PET scans are combined with CT to improve anatomical details.

Arthroscopy is a direct means of visualizing a joint, particularly the knee or shoulder. Biopsies can be taken, surgery performed in certain conditions (e.g. repair or trimming of meniscal tears), and loose bodies removed.

Common regional musculoskeletal problems (fig. 11.2)

Pain in the neck and shoulder (Table 11.4)

Mechanical or muscular neck pain (shoulder girdle pain)

Unilateral or bilateral muscular-pattern neck pain is common and usually self-limiting. It can follow injury, falling asleep in an awkward position, or prolonged keyboard working. Chronic burning neck pain occurs because of muscle tension from anxiety and stress.

Table 11.4 Pain in the neck and shoulder

Figure 11.2 Common regional musculoskeletal problems.

Spondylosis seen on X-ray increases after the age of 40 years, but it is not always causal. Spondylosis can, however, cause stiffness and increases the risk of mechanical or muscular neck pain. Muscle spasm is palpable and tender and may lead to abnormal neck posture (e.g. acute torticollis). Muscular-pattern neck pain is not localized but affects the trapezius muscle, the C7 spinous process and the paracervical musculature (shoulder girdle pain). Pain often radiates upwards to the occiput and is commonly associated with tension headaches. These features are also seen in chronic widespread pain (see p. 509).

Treatment

Patients are given short courses of analgesic therapy along with reassurance and explanation. Physiotherapists can help to relieve spasm and pain, teach exercises and relaxation techniques, and improve posture. An occupational therapist can advise about the ergonomics of the workplace if the problem is work-related (see p. 510).

Nerve root entrapment

This is caused by an acute cervical disc prolapse or pressure on the root from spondylotic osteophytes narrowing the root canal.

Acute cervical disc prolapse presents with unilateral pain in the neck, radiating to the interscapular and shoulder regions. This diffuse, aching dural pain is followed by sharp, electric shock-like pain down the arm, in a nerve root distribution, often with pins and needles, numbness, weakness and loss of reflexes (Table 11.5).

Table 11.5 Cervical nerve root entrapment: symptoms and signs

Cervical spondylosis occurs in the older patient with posterolateral osteophytes compressing the nerve root and causing root pain (see Fig. 22.58, p. 1148), commonly at C5/C6 or C6/C7; it is seen on oblique radiographs of the neck. An MRI scan clearly distinguishes facet joint OA, root canal narrowing and disc prolapse.

Treatment

A support collar, rest, analgesia and sedation are used initially as necessary. Patients should be advised not to carry heavy items. It usually recovers in 6–12 weeks. MRI is the investigation of choice if surgery is being considered or the diagnosis is uncertain (Fig. 11.3). A cervical root block administered under direct vision by an experienced pain specialist may relieve pain while the disc recovers. Neurosurgical referral is essential if the pain persists or if the neurological signs of weakness or numbness are severe or bilateral. Bilateral root pain with or without long track symptoms or signs is a neurosurgical emergency because a central disc prolapse may compress the cervical spinal cord. Posterior osteophytes may cause spinal claudication and cervical myelopathy.

Figure 11.3 MRI of cervical spine, showing a large central disc prolapse impinging on the spinal cord (arrow) at the C6/7 level.

Whiplash injury

Whiplash injury results from acceleration–deceleration forces applied to the neck, usually in a road traffic accident when the car of a person wearing a seat belt is struck from behind. A simple decision plan based on clinical criteria helps to distinguish those most at risk and who warrant radiography. There is a low probability of serious bony injury if there is:

no midline cervical tenderness

no focal neurological deficit

normal alertness

no intoxication

no other painful distracting injury.

CT scans are reserved for those with bony injury. MRI scans occasionally show severe soft tissue injury. Whiplash injuries commonly lead to litigation.

Whiplash injury is a common cause of chronic neck pain, although most people recover within a few weeks or months. Delayed recovery depends in part upon the severity of the initial injury. The pattern of chronic neck pain is often complex, involving pain in the neck, shoulder and arm. Subjective symptoms such as headache, dizziness, and poor concentration sometimes accompany this. The subjective nature of these symptoms has led to controversy about their cause. The problem is more commonly seen in industrialized countries where the conflictive nature of the compensation process may actually delay recovery. Non-conflictive means of compensation may lead to a better prognosis.

Treatment is with reassurance (the patient is often distressed and anxious), analgesia, a short-term support collar and physiotherapy. Pain may take a few weeks or months to settle and the patient should be warned of this.

Pain in the shoulder

The shoulder is a shallow joint with a large range of movement. The humeral head is held in place by the rotator cuff (Fig. 11.4) 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 movement and the greater tuberosity glides under the acromion without impingement. Shoulder pathology restricts or is made worse by shoulder movement. Specific diagnoses are difficult to make clinically but this may not matter for pain management.

Figure 11.4 The shoulder region, showing site of injection and subacromial space.

Pain in the shoulder can sometimes be due to problems in the neck. The differential diagnosis of this is shown in Box 11.1. Adhesive capsulitis (true frozen shoulder) is uncommon (see below). Early inflammatory arthritis and polymyalgia rheumatica in the elderly may present with shoulder pain. Shoulder pain is more common in diabetic patients than in the general population.

Box 11.1

Differential diagnosis of ‘shoulder’ pain

Rotator cuff tendonitis pain is worse at night and 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 pain is usually associated with pins and needles or neurological signs in the arm.

Rotator cuff (supraspinatus) tendonosis

This is a common cause of shoulder pain at all ages. It follows 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; a so-called ‘painful arc syndrome’. When examined from behind, the scapula rotates earlier than usual during elevation. Passive elevation reduces impingement and is less painful. Severe pain virtually immobilizes the joint, although some rotation is retained (cf. adhesive capsulitis, see below). There is also painful spasm of the trapezius. There may be an associated subacromial bursitis. Isolated subacromial bursitis occurs after direct trauma, falling on to the outstretched arm or elbow. Acromioclavicular osteophytes increase the risk of impingement and may need to be removed surgically.

X-rays or ultrasound are necessary only when rotator cuff tendonosis is persistent or the diagnosis is uncertain.

Treatment

Analgesics, NSAIDs and/or physiotherapy may suffice, but severe pain responds to an injection of corticosteroid into the subacromial bursa (Fig. 11.4). Patients should be warned that 10% will develop worse pain for 24–48 hours after injection. Some 70% improve over 5–20 days and mobilize the joint themselves. Physiotherapy helps persistent stiffness. Further ultrasound-guided corticosteroid injections may be needed but the long-term benefit is unclear.

Torn rotator cuff

This is caused by trauma 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 RA. Some patients require arthroscopic surgery.

Calcific tendonosis and bursitis

Calcium pyrophosphate deposits in the tendon are visible on X-ray, but they are not always symptomatic. The pathogenesis is unclear, although ischaemia may play a part. The deposit is usually 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 relieve the pain. The calcification may persist or resolve. Aspiration or breaking up of the deposit under ultrasound control may be required for persistent pain. Rarely, arthroscopic removal is necessary.

Shedding of crystals into the subacromial bursa causes a bursitis with severe pain and shoulder restriction. The shoulder feels hot and is swollen, and an X-ray shows a diffuse opacity in the bursa. The differential diagnosis of calcific bursitis is gout, pseudogout or septic arthritis. Aspiration and injection with corticosteroid can help.

Adhesive capsulitis (true ‘frozen’ shoulder)

This is uncommon but can develop with rotator cuff lesions, or following hemiplegia, chest or breast surgery or myocardial infarction. It causes severe shoulder pain and complete loss of all shoulder movements, including rotation. High doses of NSAIDs and intra-articular injections of local anaesthetic and corticosteroids are helpful. Once the pain settles, arthroscopic release speeds functional recovery.

Pain in the elbow

Pain in the elbow can be due to epicondylitis, inflammatory arthritis or occasionally osteoarthritis.

Epicondylitis

Two common sites where the insertions of tendons into bone become inflamed (enthesitis) are the insertions of the wrist extensor tendon into the lateral epicondyle (‘tennis elbow’) and the wrist flexor tendon into the medial epicondyle (‘golfer’s elbow’). Both are usually unrelated to either sporting activity.

There is local tenderness. Pain radiates into the forearm on using the affected muscles – typically, gripping or holding a heavy bag in tennis elbow or carrying a tray in golfer’s elbow. Pain at rest also occurs.

Treatment

Advise rest and arrange review by a physiotherapist. A local injection of corticosteroid at the point of maximum tenderness is helpful when the pain is severe but needs physiotherapy follow-up to prevent recurrences (Fig. 11.5). Avoid the ulnar nerve when injecting golfer’s elbow. Both conditions settle spontaneously eventually, but occasionally persist and require surgical release.

Figure 11.5 Injection for tennis elbow.

Pain in the hand and wrist (table 11.6)

Hand pain is commonly caused by injury or repetitive work-related activities. When associated with pins and needles or numbness it suggests a neurological cause arising at the wrist, elbow or neck. Pain and stiffness that are worse in the morning are due to tenosynovitis or inflammatory arthritis. The distribution of hand pain often indicates the diagnosis.

Table 11.6 Pain in the hand and wrist: causes

All ages	Older patients
Trauma/fractures	Nodal OA:
Tenosynovitis:	DIPs (Heberden’s nodes)
Flexor with/without triggering	PIPs (Bouchard’s nodes) First carpometacarpal joint
Dorsal	PIPs (Bouchard’s nodes) First carpometacarpal joint
De Quervain’s Carpal tunnel syndromeGanglionInflammatory arthritisRaynaud’s syndrome (p. 510)Chronic regional pain syndrome type I (in this chapter)	Trauma – scaphoid fracture
	Pseudogout
	Gout:
	Acute
	Tophaceous

DIPs, PIPs, distal and proximal interphalangeal joints.

Tenosynovitis

The finger flexor tendons run through synovial sheaths and under loops which hold them in place. Inflammation occurs with repeated or unaccustomed use, or in inflammatory arthritis. The thickened sheaths are often palpable.

Flexor tenosynovitis causes finger pain when gripping and stiffness of the fingers in the morning. Occasionally a tendon causes a trigger finger, when the finger remains flexed in the morning or after gripping and has to be pulled straight. A tender tendon nodule is palpable, usually in the distal palm. Trigger finger or thumb is commoner in diabetic patients.

Dorsal tenosynovitis is less common except in rheumatoid arthritis. The hourglass swelling extends from the back of the hand and under the extensor retinaculum.

De Quervain’s tenosynovitis causes pain and swelling around the radial styloid where the abductor pollicis longus tendon is held in place by a retaining band. There is local tenderness, and the pain at the styloid is worsened by flexing the thumb into the palm.

Treatment

Resting, splinting and NSAIDs may help. Local corticosteroids injected alongside the tendon under low pressure (not into the tendon itself) are helpful. Occasionally surgery is needed if symptoms persist.

Carpal tunnel syndrome

This is due to median nerve compression in the limited space of the carpal tunnel. Thickened ligaments, tendon sheaths or bone enlargement can cause it, but it is usually idiopathic. (Causes are discussed on p. 1144.) The history is usually typical and diagnostic with the patient waking with numbness, tingling and pain in a median nerve distribution. The pain radiates to the forearm. The fingers feel swollen but usually are not. Wasting of the abductor pollicis brevis develops with sensory loss in the radial three and a half fingers. The pain may be produced by tapping the nerve in the carpal tunnel (Tinel’s sign) or by holding the wrist in flexion (Phalen’s test).

Treatment is with a splint to hold the wrist in dorsiflexion overnight. This relieves the symptoms and is diagnostic; used nightly for several weeks it may produce full recovery. If it does not, a corticosteroid injection into the carpal tunnel (avoid the nerve!) helps in about 70% of cases, although it may recur. Persistent symptoms or nerve damage produce prolonged latency across the carpal tunnel on nerve conduction studies and require surgical decompression.