Osteoarthritis

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Osteoarthritis is use-related pain and functional limitation caused by failure of the whole synovial joint. Common sites are knees, hips, first metatarsophalangeal joints, thumb bases and distal or proximal finger joints. Ask which activities provoke symptoms, how long stiffness lasts after waking or rest, whether swelling is abrupt or persistent, and how pain affects walking, stairs, sleep, work, self-care and valued activities. Establish prior injury, inflammatory disease, dysplasia, occupational loading, medicines, gastrointestinal or kidney disease, cardiovascular risk, falls and the person's priorities.

Typical findings include bony enlargement, crepitus, restricted movement, malalignment, joint-line tenderness and reduced supporting muscle strength. Effusions can occur, but intense warmth, fever or rapid fluid accumulation needs a different pathway. Assess gait and adjacent joints, distinguish joint restriction from periarticular tenderness or spinal referral, and record function rather than reducing severity to a pain score. Heberden and Bouchard nodes support hand osteoarthritis; hip disease commonly produces groin or anterior-thigh pain and reduced internal rotation.

Management combines explanation, progressive strength and aerobic activity, weight support where relevant, aids or work adaptation, and carefully chosen symptom relief. Imaging may look advanced with little disability or modest despite severe pain because it cannot show every pain generator. Decisions therefore centre on symptoms, function, comorbidity and goals. Review after an agreed interval, address barriers to exercise, withdraw ineffective medicines and refer without requiring patients to exhaust unsafe analgesics.

Key points

In an adult aged 45 years or older, activity-related joint pain with absent morning stiffness or stiffness lasting no longer than 30 minutes can usually be diagnosed clinically as osteoarthritis.
Do not request routine imaging to confirm a typical presentation; image when features are atypical, trauma or another diagnosis is suspected, or a result will change procedural planning.
Therapeutic exercise and sustained weight-loss support when appropriate are core treatments; temporary discomfort after starting exercise does not mean joint damage is accelerating.
For knee osteoarthritis, offer a topical NSAID before an oral NSAID; if oral treatment is needed, use the lowest effective dose briefly with gastroprotection.
Do not routinely offer strong opioids, glucosamine, acupuncture, dry needling or electrotherapy; paracetamol and weak opioids are limited rescue options when alternatives cannot be used.
An intra-articular corticosteroid can provide relief for roughly two to ten weeks to enable rehabilitation, but is neither disease modifying nor an indefinite repeated treatment.
Refer for joint replacement when symptoms and reduced function substantially affect quality of life despite appropriate non-surgical care, without requiring a particular radiographic grade.
Do not deny referral solely because of age, sex, smoking, comorbidity, disability or body mass index; discuss individual operative risk and optimisation instead.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Age and tissue susceptibility

Prevalence rises with age as cartilage, subchondral bone, menisci, ligaments and periarticular muscle become less able to absorb repeated mechanical stress and repair small injuries.

Mechanical loading

Obesity, occupational kneeling or lifting, malalignment, instability, muscle weakness and previous joint injury increase focal load; hand disease also has a substantial genetic component.

Secondary joint damage

Congenital dysplasia, slipped epiphysis, inflammatory arthritis, haemochromatosis, avascular necrosis, infection and intra-articular fracture can produce earlier or atypically distributed osteoarthritis.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Whole-joint failure
Osteoarthritis is not simple cartilage wear. Chondrocyte stress, matrix loss, subchondral remodelling, osteophytes, low-grade synovitis and altered muscle control interact across the joint.
2
Load concentration
Malalignment or instability concentrates force on a smaller articular area; cartilage loss then narrows joint space and transfers additional stress to innervated subchondral bone.
3
Pain generation
Cartilage lacks nerves. Pain arises from synovium, capsule, periosteum, bone-marrow lesions, periarticular tissues and sensitised nociceptive pathways, explaining imperfect radiograph-symptom correlation.
4
Functional deconditioning
Pain-related avoidance weakens supporting muscle and reduces confidence, balance and cardiovascular fitness, amplifying disability and load per movement even when structural change is stable.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Typical clinical diagnosis

Age at least 45 years, activity-related joint pain and morning stiffness absent or no longer than 30 minutes form the NICE clinical pattern.

Knee pattern

Pain with walking, stairs or rising, brief gelling after sitting, crepitus, bony enlargement, effusion and quadriceps weakness are characteristic.

Hip pattern

Groin, buttock or anterior-thigh pain with reduced internal rotation and difficulty putting on footwear suggests hip-joint disease; knee pain may be referred.

Hand pattern

Thumb-base pain, first carpometacarpal squaring and nodal distal or proximal interphalangeal enlargement occur, while metacarpophalangeal synovitis suggests an alternative.

Atypical inflammatory pattern

Prolonged morning stiffness, rapid deterioration, marked warmth, systemic illness or persistent soft swelling should trigger assessment for infection, crystals or inflammatory arthritis.

Impact beyond pain

Observe gait, sit-to-stand ability, grip, balance and muscle strength, and ask about sleep, mood, falls, caring responsibilities and occupational consequences.

Red flags requiring action

Fever, rigors, marked warmth, rapid effusion or immunosuppression with acute monoarthritis requires urgent exclusion of septic arthritis rather than attribution to an osteoarthritis flare.
Progressive night pain unrelated to movement, unexplained weight loss, a mass or previous cancer warrants investigation for malignancy or destructive bone disease.
Major trauma, sudden inability to bear weight, deformity or focal bony tenderness requires a fracture or dislocation pathway, especially in an older or osteoporotic adult.
New motor weakness, saddle sensory loss, bladder dysfunction, a cold limb or absent pulses indicates neurological or vascular compromise and needs emergency assessment.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line clinical assessmentFirst stepFirst line
Why
Make a positive diagnosis in a typical adult and identify findings requiring a competing diagnostic pathway.
Interpretation and limitations
Compatible age, mechanical pain and brief stiffness usually need no confirmatory test; warmth, systemic features, prolonged stiffness or unusual distribution changes investigation.
02
Plain radiography when actionable
Why
Assess trauma, deformity, atypical progression, alternative bone disease or anatomy before specialist intervention.
Interpretation and limitations
Joint-space narrowing, osteophytes, sclerosis and cysts support osteoarthritis but do not determine pain intensity; a normal early film does not invalidate symptoms.
03
Targeted blood tests
Why
Investigate inflammatory, metabolic, infectious or malignant alternatives rather than screen every person with mechanical pain.
Interpretation and limitations
Choose FBC, CRP or ESR, renal or liver profile, calcium, urate or disease-specific serology from the history; normal markers do not confirm osteoarthritis.
04
Urgent synovial-fluid analysis
Why
Differentiate septic and crystal arthritis when an acutely hot swollen joint or unexplained large effusion is present.
Interpretation and limitations
Send cell count, Gram stain, culture and crystals before antibiotics when safe, but never delay sepsis treatment; crystals do not rule out infection.
05
Selective ultrasound or MRI
Why
Answer a focused soft-tissue, occult structural or operative-planning question that examination and radiography cannot resolve.
Interpretation and limitations
Synovitis, meniscal abnormalities and cartilage loss are common incidental findings; interpret imaging against the management question, not as a pain scale.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Inflammatory arthritis

Persistent soft swelling, prolonged morning stiffness, systemic features or symmetrical small-joint disease suggests rheumatoid, psoriatic or another inflammatory arthritis rather than isolated mechanical disease.

Crystal or septic arthritis

Abrupt severe pain with warmth and effusion may be gout, calcium-pyrophosphate arthritis or infection; finding crystals does not exclude coexisting sepsis.

Referred and periarticular pain

Radiculopathy, trochanteric pain, tendinopathy and bursitis can mimic joint pain; preserved passive movement and pain reproduced outside the joint redirect examination.

Structural bone disease

Occult fracture, osteonecrosis, malignancy and Paget disease deserve consideration when onset, age, location, systemic context or pain behaviour is atypical.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01First-lineBuild an individual non-drug planFirst stepFirst lineAlternativeA clinical diagnosis is secure and no red flag or urgent alternative explains the painful joint.

1Explain whole-joint disease, the imperfect image-pain relationship, expected fluctuations and why gradual movement is protective rather than evidence of further wear.
2Offer tailored local muscle strengthening plus aerobic activity, beginning within tolerance and progressing dose, frequency or resistance with physiotherapy support when needed.
3If excess weight contributes, offer respectful sustained weight-management support; any loss may help, while around ten percent generally improves symptoms more than five percent.
4Address footwear, pacing, work tasks, walking aids and falls, using devices because they solve a defined biomechanical or functional problem.

02Stepwise analgesiaAdd the least harmful effective optionPain continues to prevent sleep, movement or rehabilitation despite education, exercise adaptation and non-drug support.

1For knee disease offer a topical NSAID; consider it at other accessible joints while reviewing skin tolerance and cumulative NSAID exposure.
2If topical treatment is ineffective or unsuitable, consider a brief oral NSAID only after gastrointestinal, kidney, liver, cardiovascular, interaction and pregnancy assessment, with gastroprotection.
3Reserve infrequent short-term paracetamol or a weak opioid for circumstances where other medicines cannot be used, and avoid strong opioids.
4Consider one intra-articular corticosteroid injection when short-lived relief could enable exercise, explaining the expected two-to-ten-week benefit.

03EscalationRefer according to life impactEscalationPain, stiffness, deformity or lost function substantially impairs quality of life despite suitable non-surgical treatment.

1Confirm the symptom source, document useful treatments attempted and establish which function the person hopes surgery would restore.
2Refer for orthopaedic assessment without a minimum radiographic grade or exclusion based solely on age, smoking, disability, comorbidity or BMI.
3Discuss individual benefit, infection and thromboembolic risks, rehabilitation and work or caring arrangements while optimising health in parallel.

04Urgent alternativeLeave the routine pathway safelyAlternativeThe joint is acutely hot, symptoms follow major trauma, systemic illness is present or neurological, vascular or malignant features emerge.

1Repeat observations and examine skin, effusion, perfusion and neurology; never inject a joint when infection has not been excluded.
2Arrange urgent radiography for suspected fracture or dislocation and same-day acute care for possible septic arthritis, collecting cultures where feasible.
3Use an expedited cancer, spinal or vascular route when progressive night pain, a mass, neurological loss or limb ischaemia indicates time-dependent disease.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

Preferred initial pharmacological treatment for knee osteoarthritis and a reasonable local option for other accessible joints when non-drug care is insufficient.

Topical diclofenac gel

Apply the product-specified amount to the painful joint, commonly 2–4 g of 1.16% gel three or four times daily; remain below the product maximum and review after two to four weeks.

Avoid broken skin, NSAID hypersensitivity and concurrent excess NSAID exposure; systemic harms remain possible. In pregnancy use only when clearly necessary and avoid completely during the third trimester.

An oral option when topical treatment is ineffective or unsuitable and pain materially obstructs function or therapeutic exercise.

Naproxen with gastroprotection

Take 250 mg orally twice daily and increase if necessary to 500 mg twice daily, with food, for the shortest course; add omeprazole 20 mg once daily unless another protective plan is chosen.

Assess ulcer history, anticoagulants, eGFR, heart failure, blood pressure and cardiovascular disease. Avoid severe kidney disease and pregnancy from 20 weeks unless necessary; contraindicated from 28 weeks.

An occasional short rescue option when NSAIDs are contraindicated, not tolerated or ineffective; routine long-term osteoarthritis benefit is limited.

Paracetamol

Use 500 mg–1 g orally at intervals of at least four hours when needed, maximum 4 g in 24 hours for a suitable adult; lower the ceiling with low weight, frailty, malnutrition or liver risk.

Count combination products to prevent overdose and avoid automatic repeats. Therapeutic excess can cause liver failure, especially with low weight, alcohol dependence, fasting or hepatic disease.

Provides temporary symptom relief when pain blocks rehabilitation or other pharmacological options are unsuitable.

Intra-articular triamcinolone acetonide

Inject 10–40 mg according to joint size, preparation and trained local protocol; a large knee commonly receives 40 mg once, with repeat considered only after reassessment.

Exclude joint or overlying infection, use aseptic technique, warn about post-injection flare and transient hyperglycaemia, and consider timing before arthroplasty; repeated exposure may damage cartilage.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Progressive disability

Pain, stiffness, deformity and reduced range can restrict walking, hand function, work, self-care and participation, with secondary loss of independence.

Falls and deconditioning

Weakness, poor balance, fear of movement and inactivity increase falls, frailty, weight gain and cardiometabolic risk, creating a self-reinforcing disability cycle.

Analgesic harm

Oral NSAIDs can cause gastrointestinal bleeding, kidney injury, fluid retention and cardiovascular events; opioids add constipation, sedation, dependence and falls.

Psychosocial consequences

Persistent pain can disturb sleep, mood, employment and relationships; these treatable contributors to disability do not imply that symptoms are unreal.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Agree a functional outcome such as walking distance, stair use, sleep or a hand task, then review exercise adherence, progression and barriers rather than pain alone.
After an oral NSAID, reassess benefit and adverse effects promptly; check renal function, blood pressure and haemoglobin according to age, comorbidity and duration.
Review weight support without stigma, including nutrition, muscle preservation and realistic trajectory; improvement can occur before a target weight is reached.
Reconsider the diagnosis if symptoms change character, stiffness lengthens, swelling becomes persistently warm, function deteriorates rapidly or systemic features appear.
After injection, give infection warning advice and assess whether short-term relief enabled rehabilitation; avoid repeating an ineffective procedure.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Symptoms outrank the image

Radiographic severity and pain correlate only moderately; base escalation on quality-of-life impact, functional restriction and informed preference.

Exercise may hurt briefly

A short initial increase in discomfort is common when strengthening starts; appropriate progression improves pain and function without accelerating cartilage loss.

Injection creates a window

Corticosteroid is most useful when temporary analgesia permits movement, sleep or therapy; it should not replace rehabilitation or delay referral.

Referral is not BMI-rationed

BMI affects peri-operative discussion and optimisation, but NICE advises against using it, age or comorbidity alone to withhold joint-replacement referral.

11Common pitfallsFrequent interpretation and management errors.

01
Do not label every painful joint in an older adult as osteoarthritis; acute warmth, prolonged stiffness, constitutional symptoms and rapid progression demand a fresh differential.
02
Do not order imaging reflexively or imply that a severe-looking radiograph proves inevitable decline; incidental structural change is common.
03
Do not advise complete rest, which weakens muscle, reduces confidence and worsens the functional consequences treatment should reverse.
04
Do not move from topical treatment to chronic opioid prescribing without reassessing diagnosis, rehabilitation, comorbidity and referral threshold.
05
Do not inject through cellulitis or into a possibly infected joint, and never let a planned injection delay synovial sampling.
06
Do not require failure of every analgesic before referral when symptoms substantially impair life and further exposure would be unsafe.