Septic arthritis

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

INITIAL

suspected infection in any joint(s): systemic involvement

1st line – follow local protocol for suspected sepsis

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1st line –

follow local protocol for suspected sepsis

Think 'Could this be sepsis?' based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[16][17][18] See Sepsis in adults.

The patient may present with non-specific or non-localised symptoms (e.g., acutely unwell with a normal temperature) or there may be severe signs with evidence of multi-organ dysfunction and shock.[16][17][18]
Remember that sepsis represents the severe, life-threatening end of infection.[29]

Use a systematic approach (e.g., national early warning score [NEWS] 2), alongside your clinical judgement, to assess the risk of deterioration due to sepsis.[16][17][30][31] Consult local guidelines for the recommended approach at your institution.

Arrange urgent review by a senior clinical decision-maker (e.g., ST4 level doctor in the UK) if you suspect sepsis:[19]

Within 30 minutes for a patient who is critically ill (e.g., NEWS2 score of 7 or more, evidence of septic shock, or other significant clinical concerns).
Within 1 hour for a patient who is severely ill (e.g., NEWS2 score of 5 or 6).

Follow your local protocol for investigation and treatment of all patients with suspected sepsis, or those at risk. Start treatment promptly. Determine urgency of treatment according to likelihood of infection and severity of illness, or according to your local protocol.[19][31]

suspected infection in prosthetic joint(s): no systemic involvement

1st line – refer to orthopaedics to consider surgery

suspected infection in native joint(s): no systemic involvement

inaccessible joint

1st line – refer to orthopaedics for ultrasound-guided joint aspiration

accessible joint

1st line – empirical antibiotics

Back

1st line –

empirical antibiotics

Immediately after you have aspirated the joint, taken blood for culture, and taken any necessary swabs or samples for biological processing, (e.g., genitourinary, skin, respiratory), start empiric intravenous antibiotics in patients with suspected septic arthritis (without systemic involvement).[10]

Consult your local antibiotic protocol to determine the most appropriate choice based on local pathogen prevalence and antibiotic resistance patterns.

Take into account individual patient demographic and clinical factors (e.g., age, immunocompromise) as these might indicate the most likely organism.
In practice, look for any of the patient’s recent microbiology results, such as past skin swabs, and any past methicillin-resistant staphylococcus aureus (MRSA) screening results. If patients were identified as carrying MRSA, assume that they need treatment which is effective against MRSA.
Consult a microbiologist or infectious disease specialist in all cases.
Consult with a senior colleague about your decision to start antibiotics at the earliest opportunity.
See our Antibiotics section in Management: full recommendations for antibiotics recommended by the British Society of Rheumatology.

It is important to make an early, accurate diagnosis of infection and use antibiotics appropriately.

In patients with no risk factors for atypical organisms, staphylococci or streptococci account for 91% of cases.[4][5] Patients at increased risk for septic arthritis include those with:[10]

Joint disease (septic arthritis is more common in pre-existing joint disease)
Gout/pseudogout
Chronic systemic disease (relates to impaired host defences)
Corticosteroids or immunomodulators (particularly tumour necrosis factor [TNF]-alpha inhibitors)
Recent intra-articular injections
Skin or soft-tissue infection.

Add in cover for MRSA depending on local prevalence and local antibiotic policy.

Patients at increased risk for MRSA include:[10]

Recent inpatients
Nursing home residents
Those with leg ulcers or urinary catheters.

The most common causative gram-negative organisms are Pseudomonas aeruginosa and Eschericia coli. Gram-negative rod infections are more likely in:[10]

Elderly or frail patients
Patients with recurrent urinary tract infections
Patients who have had recent abdominal surgery.

Patients without other risk factors for septic arthritis and who are young, healthy, and sexually active may have gonococcal septic arthritis. There may be a history of prodromal flitting polyarthritis.

Unusual organisms may cause septic arthritis in patients who are intravenous drug misusers or who are known to have colonisation of other organs (e.g., cystic fibrosis).[10]

Penetrating trauma may cause septic arthritis with anaerobic organisms.[10][15]

Exposure to ticks in endemic areas may cause septic arthritis. Being bitten by a tick does not necessarily cause Lyme disease.[14] However, a history of erythema migrans, migratory joint pains, and, later, intermittent oligoarthritis usually involving the knee or other large joints may indicate the causative organism.[14]

Note travel to or residence in:

Many parts of the US: Eastern states (mainly New England and the mid-Atlantic), Northern midwestern states (especially Wisconsin, Minnesota, and the Great Lakes region), and the West Coast (particularly northern California and, less commonly, Oregon and Washington)[32]
Grassy/wooded areas in the UK and the Highlands in Scotland[14]
Central Europe, especially Austria, Czech Republic, southern Germany, Switzerland, Slovakia, and Slovenia[33]
Some parts of Asia (Lyme disease is well established in China).[34]

In the UK, the National Institute for Health and Care Excellence guideline on Lyme disease makes recommendations on specific treatment. NICE: Lyme disease Opens in new window

Gram-stain or polymerase chain reaction (PCR)-directed antibiotics

Narrow antibiotic treatment according to local antibiotic policy after Gram stain or PCR results and in discussion with microbiology.[9][10][58]

If Gram stain and PCR are negative, but you still suspect a septic joint clinically, guidance from the US suggests giving a broad-spectrum antibiotic regimen.[9]

Plus – joint aspiration

Back

Plus –

joint aspiration

Treatment recommended for ALL patients in selected patient group

Admit all patients with suspected septic arthritis.[10]

Aspirate the joint to dryness as often as necessary.[10]

This helps remove infection and manage pain (caused by acute increase in pressure) by relieving pressure within the joint.
Guidelines do not stipulate the best method of aspiration to dryness. In UK practice, repeated arthroscopic washouts are indicated if temperature and inflammatory markers do not improve after the initial aspiration and treatment; a non-specialist doctor may perform this procedure if they have been appropriately trained.

Practical tip

In practice, you can use as many syringes as necessary to aspirate the joint to dryness. Simply detach the first syringe from the needle and attach the next using aseptic technique. Note that the larger the syringe (e.g., 20 mL) the larger the force required to aspirate, especially if the synovial fluid is very thick.

Evacuation of pus with arthrocentesis or surgery may be necessary, particularly if the pus is thick or dry.[10][28] In practice, a senior colleague with the appropriate skills may be required to perform this procedure.

To assess clinical response, send joint aspirates for microscopy, culture, and sensitivities.[9]

Aspiration and injection of the knee animated demonstration

How to aspirate synovial fluid from the knee and administer intra-articular medication using a medial approach.

Aspiration and injection of the shoulder animated demonstration

How to aspirate synovial fluid from the shoulder and administer intra-articular medication. Video demonstrates a posterior approach to the glenohumeral joint and a lateral approach to the subacromial space.

Consider – analgesia

Back

Consider –

analgesia

Additional treatment recommended for SOME patients in selected patient group

Prescribe simple analgesics such as paracetamol or a non-steroidal anti-inflammatory drug (NSAID), such as ibuprofen or diclofenac, if the patient reports ongoing pain.

Practical tip

Beware of prescribing opioids prior to joint aspiration in older people, because respiratory depression may occur when the painful stimulus is removed.[62]

Be cautious when prescribing NSAIDs to older people and people with comorbidities such as hypertension and heart disease. NSAIDs may increase the risk of acute kidney injury in people with sepsis.

Primary options

paracetamol: oral: 500-1000 mg orally every 4-6 hours when required, maximum 4000 mg/day; intravenous (<51 kg body weight): 15 mg/kg intravenously every 4-6 hours when required, maximum 60 mg/kg/day; intravenous (≥51 kg body weight): 1000 mg intravenously every 4-6 hours when required, maximum 4000 mg/day (3000 mg/day if risk factors for hepatotoxicity)

ibuprofen: 300-600 mg orally (immediate-release) every 6-8 hours when required, maximum 2400 mg/day

diclofenac potassium: 75-150 mg/day orally (immediate-release) given in 2-3 divided doses when required

ACUTE

confirmed infection in any joint(s): systemic involvement

1st line – follow local protocol for suspected sepsis

Back

1st line –

follow local protocol for suspected sepsis

Think 'Could this be sepsis?' based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[16][17][18] See Sepsis in adults.

The patient may present with non-specific or non-localised symptoms (e.g., acutely unwell with a normal temperature) or there may be severe signs with evidence of multi-organ dysfunction and shock.[16][17][18]
Remember that sepsis represents the severe, life-threatening end of infection.[29]

Use a systematic approach (e.g., national early warning score [NEWS] 2), alongside your clinical judgement, to assess the risk of deterioration due to sepsis.[16][17][31][30] Consult local guidelines for the recommended approach at your institution.

Arrange urgent review by a senior clinical decision-maker (e.g., ST4 level doctor in the UK) if you suspect sepsis:[19]

Within 30 minutes for a patient who is critically ill (e.g., NEWS2 score of 7 or more, evidence of septic shock, or other significant clinical concerns).
Within 1 hour for a patient who is severely ill (e.g., NEWS2 score of 5 or 6).

confirmed infection in prosthetic joint(s): no systemic involvement

1st line – refer to orthopaedics to consider surgery

Consider – analgesia

Back

Consider –

analgesia

Additional treatment recommended for SOME patients in selected patient group

Prescribe simple analgesics such as paracetamol or a non-steroidal anti-inflammatory drug (NSAID) (e.g., ibuprofen, diclofenac) if the patient reports ongoing pain.

Practical tip

Be cautious when prescribing NSAIDs to older people and people with comorbidities such as hypertension and heart disease. NSAIDs may increase the risk of acute kidney injury in people with sepsis.

Primary options

ibuprofen: 300-600 mg orally (immediate-release) every 6-8 hours when required, maximum 2400 mg/day

diclofenac potassium: 75-150 mg/day orally (immediate-release) given in 2-3 divided doses when required

confirmed infection in native joint(s): no systemic involvement

1st line – pathogen-targeted antibiotics

Back

1st line –

pathogen-targeted antibiotics

Adjust antibiotics in line with microbiology culture and sensitivity results when they become available.[10]

Always consult a microbiologist about appropriate antibiotic choices, route and duration in line with local protocols.

Continue intravenous antibiotics for a total of 2 weeks, unless the patient shows signs of lack of response. Although there is no specific evidence base to support this duration, it is usual practice to continue intravenous therapy for 14 days before switching to oral antibiotics.[10]

After 2 weeks of intravenous therapy start oral antibiotics that:

Have the same spectrum of activity as the intravenous antibiotics that achieved clinical response
Are known to achieve adequate intra-articular concentrations.[10]

Continue oral antibiotics for 4 weeks.

Note that some septic arthritides may require a shorter intravenous and total treatment duration (e.g., gonococcal arthritis and Lyme arthritis). Refer to your local protocols.

Practical tip

Check for signs of re-emerging infection 24 to 48 hours after starting oral antibiotic treatment and before discharging the patient home.

Evidence: Duration of antibiotics

Evidence suggests that it may be safe to reduce the duration of intravenous antibiotics (with earlier switching to the oral route) and the overall duration of antibiotic therapy for patients with joint infections.

Current British Society for Rheumatology guidelines (published in 2006) state that the joint should be aspirated to remove pus, and that antibiotics are conventionally (based on expert opinion) given intravenously for up to 2 weeks or until signs improve, then orally for around 4 weeks to achieve adequate joint and bone concentrations.[10]
Despite this convention, a large randomised controlled trial (RCT) found that switching to oral antibiotic therapy at an earlier stage has similar results in selected patients.
- The Oral versus Intravenous Antibiotics for Bone and Joint Infection (OVIVA) trial (published in 2019) is an RCT of over 1000 adults with osteomyelitis, native or prosthetic joint infection, or orthopaedic fixation-device infection, who would conventionally have been treated with 6 weeks of intravenous antibiotic therapy in addition to surgical intervention.[59]
- Patients were randomised to 6 weeks or 1 week of intravenous antibiotic therapy, followed by oral therapy, mostly after surgical debridement or removal of infected prosthetic joints.
- The difference in the risk of definitive treatment failure at 1 year (oral group vs. intravenous group) in the intention-to-treat population was -1.4 percentage points (95% CI -5.6 to +2.9), indicating non-inferiority of the oral regimen.
- Longer intravenous therapy was associated with significantly longer hospital stay (median 14 [interquartile range: 11 to 21] days vs. 11 [8 to 20] days, P <0.001) and more complications associated with the intravenous catheter (49 of 523 [9.4%] vs. 5 of 523 [1.0%], P <0.001).
- However, the authors note that oral antibiotic therapy may not be appropriate for some patients (e.g., those with poor enteral absorption) and some pathogens (e.g., those with resistance to oral agents).
- Expert commentary in a UK National Institute of Health Research (NIHR) signal suggests that this research is potentially significant for patients and the National Health Service (NHS) in the UK because of the freedom afforded to patients and the potential cost savings to the NHS.[59][60]
Another RCT (also published in 2019) found no significant difference in remission of infection in patients (total 154) after surgical drainage of native joint bacterial arthritis (mostly in the hand and wrist) receiving 2 weeks versus 4 weeks of total antibiotic therapy.[61]
- Patients receiving 2 weeks of antibiotic therapy received this intravenously for a median of 1 day, while those receiving 4 weeks of therapy received this intravenously for a median of 2 days.
- The primary outcome for this study was the remission of infection (defined as a complete absence of clinical, laboratory, or radiological findings after a minimum follow-up of 2 months), which was achieved by 99% of patients in the 2-week group and 97% in the 4-week group (not significantly different).
- There was no difference between the groups in the number of adverse events or mechanical or neurological sequelae.

Plus – joint aspiration

Back

Plus –

joint aspiration

Treatment recommended for ALL patients in selected patient group

Aspirate the joint to dryness as often as necessary.[10]

This helps remove infection and manage pain (caused by acute increase in pressure) by relieving pressure within the joint.
Guidelines do not stipulate the best method of aspiration to dryness. In UK practice, repeated arthroscopic washouts are indicated if temperature and inflammatory markers do not improve after the initial aspiration and treatment; a non-specialist doctor may perform this procedure if they have been appropriately trained.

Practical tip

To assess clinical response, send joint aspirates for microscopy, culture, and sensitivities.[9]

Aspiration and injection of the knee animated demonstration

How to aspirate synovial fluid from the knee and administer intra-articular medication using a medial approach.

Consider – analgesia

Back

Consider –

analgesia

Additional treatment recommended for SOME patients in selected patient group

Prescribe simple analgesics such as paracetamol or a non-steroidal anti-inflammatory drug (NSAID) (e.g., ibuprofen, diclofenac) if the patient reports ongoing pain.

Practical tip

Be cautious when prescribing NSAIDs to older people and people with comorbidities such as hypertension and heart disease. NSAIDs may increase the risk of acute kidney injury in people with sepsis.

Primary options

ibuprofen: 300-600 mg orally (immediate-release) every 6-8 hours when required, maximum 2400 mg/day

diclofenac potassium: 75-150 mg/day orally (immediate-release) given in 2-3 divided doses when required

unconfirmed infection with clinically suspected infection in native joint(s): no systemic involvement

responding to empirical antibiotics

1st line – continue empirical antibiotics

Plus – joint aspiration

Back

Plus –

joint aspiration

Treatment recommended for ALL patients in selected patient group

A spirate the joint to dryness as often as necessary.[10]

This helps remove infection and manage pain (caused by acute increase in pressure) by relieving pressure within the joint.
Guidelines do not stipulate the best method of aspiration to dryness. In UK practice, repeated arthroscopic washouts are indicated if temperature and inflammatory markers do not improve after the initial aspiration and treatment; a non-specialist doctor may perform this procedure if they have been appropriately trained.

Practical tip

To assess clinical response, send joint aspirates for microscopy, culture, and sensitivities.[9]

Aspiration and injection of the knee animated demonstration

How to aspirate synovial fluid from the knee and administer intra-articular medication using a medial approach.

Aspiration and injection of the shoulder animated demonstration

Consider – analgesia

Back

Consider –

analgesia

Additional treatment recommended for SOME patients in selected patient group

Prescribe simple analgesics such as paracetamol or a non-steroidal anti-inflammatory drug (NSAID) (e.g., ibuprofen, diclofenac) if the patient reports ongoing pain.

Practical tip

Be cautious when prescribing NSAIDs to older people and people with comorbidities such as hypertension and heart disease. NSAIDs may increase the risk of acute kidney injury in people with sepsis.

Primary options

ibuprofen: 300-600 mg orally (immediate-release) every 6-8 hours when required, maximum 2400 mg/day

diclofenac potassium: 75-150 mg/day orally (immediate-release) given in 2-3 divided doses when required

not responding to empirical antibiotics

1st line – senior clinician review

Plus – joint aspiration

Back

Plus –

joint aspiration

Treatment recommended for ALL patients in selected patient group

A spirate the joint to dryness as often as necessary.[10]

This helps remove infection and manage pain (caused by acute increase in pressure) by relieving pressure within the joint.
Guidelines do not stipulate the best method of aspiration to dryness. In UK practice, repeated arthroscopic washouts are indicated if temperature and inflammatory markers do not improve after the initial aspiration and treatment; a non-specialist doctor may perform this procedure if they have been appropriately trained.

Practical tip

To assess clinical response, send joint aspirates for microscopy, culture, and sensitivities.[9]

Aspiration and injection of the knee animated demonstration

How to aspirate synovial fluid from the knee and administer intra-articular medication using a medial approach.

Aspiration and injection of the shoulder animated demonstration

Consider – analgesia

Back

Consider –

analgesia

Additional treatment recommended for SOME patients in selected patient group

Prescribe simple analgesics such as paracetamol or a non-steroidal anti-inflammatory drug (NSAID) (e.g., ibuprofen, diclofenac) if the patient reports ongoing pain.

Practical tip

Be cautious when prescribing NSAIDs to older people and people with comorbidities such as hypertension and heart disease. NSAIDs may increase the risk of acute kidney injury in people with sepsis.

Primary options

ibuprofen: 300-600 mg orally (immediate-release) every 6-8 hours when required, maximum 2400 mg/day

diclofenac potassium: 75-150 mg/day orally (immediate-release) given in 2-3 divided doses when required

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Septic arthritis

Treatment algorithm

suspected infection in any joint(s): systemic involvement

follow local protocol for suspected sepsis

suspected infection in prosthetic joint(s): no systemic involvement

refer to orthopaedics to consider surgery

suspected infection in native joint(s): no systemic involvement

inaccessible joint

refer to orthopaedics for ultrasound-guided joint aspiration

accessible joint

empirical antibiotics

Gram-stain or polymerase chain reaction (PCR)-directed antibiotics

joint aspiration

Practical tip

analgesia

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

confirmed infection in any joint(s): systemic involvement

follow local protocol for suspected sepsis

confirmed infection in prosthetic joint(s): no systemic involvement

refer to orthopaedics to consider surgery

analgesia

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

confirmed infection in native joint(s): no systemic involvement

pathogen-targeted antibiotics

Practical tip

Evidence: Duration of antibiotics

joint aspiration

Practical tip

analgesia

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

unconfirmed infection with clinically suspected infection in native joint(s): no systemic involvement

responding to empirical antibiotics

continue empirical antibiotics

joint aspiration

Practical tip

analgesia

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

not responding to empirical antibiotics

senior clinician review

joint aspiration

Practical tip

analgesia

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options