Hip Septic Arthritis and Joint Damage After Infection
Septic arthritis of the hip is a bacterial infection of the joint that can destroy articular cartilage within days. It is an orthopaedic emergency, managed acutely on the NHS via A&E. Even after the infection is eradicated, the joint is often permanently damaged, and patients are eventually left with chronic post-infection arthritis. Mr Shakir Hussain, Consultant Orthopaedic Surgeon at the Royal Orthopaedic Hospital Birmingham, performs late reconstruction with hip replacement (often as a two-stage procedure) once the infection is confirmed cleared.
What is hip septic arthritis?
Hip septic arthritis is a bacterial infection of the hip joint. Bacteria reach the joint either through the bloodstream from another infection site, via direct inoculation from a wound or prior surgery, or by spread from adjacent osteomyelitis. Once inside the joint, bacteria multiply rapidly, and the body's immune response and the bacterial enzymes together destroy articular cartilage within days if left untreated.
The hip joint is enclosed within a strong fibrous capsule that traps pus and pressure during infection, compounding the cartilage damage. Hip septic arthritis is therefore particularly aggressive and time-critical. The two clinical groups affected most often are young children (haematogenous spread is common in this group) and older adults with risk factors (diabetes, immunosuppression, intravenous drug use, or a prosthetic joint).
The natural history without treatment is rapid cartilage destruction, joint capsule erosion, secondary osteomyelitis of the femoral head, and eventually fibrous or bony ankylosis (a fused, painful joint). Even with prompt treatment, cartilage damage often persists, producing chronic post-infection arthritis that may require reconstruction years later.
The condition is rare overall (annual incidence around 4 to 10 per 100,000 in the general adult population, higher in at-risk groups) but its severity is disproportionate. The standard of care is emergency surgical washout and intravenous antibiotics, delivered through the NHS on-call orthopaedic pathway.
How does hip septic arthritis present?
Acute hip septic arthritis presents with sudden severe hip pain, fever, inability to bear weight, and refusal to move the leg. The patient looks systemically unwell. The hip is typically held in flexion, external rotation, and abduction, the position that maximises joint capsule volume and minimises pain. This is a medical emergency requiring immediate hospital admission and surgical washout.
Recognising hip septic arthritis quickly is what saves the joint. The classic presentation is unmistakable in a previously well patient, but it can be subtler in immunocompromised or older patients who may not mount a fever, and in patients with an existing hip replacement where infection can be smouldering rather than acute.
Sudden severe hip pain
Constant deep pain in the groin, often disproportionate to anything that might have caused it. Movement of the hip is excruciating. The pain does not ease with rest in the way osteoarthritis or impingement pain does.
Fever and feeling unwell
Fever (typically over 38°C), shivering, and a general systemic unwell feeling. Some immunocompromised or older patients do not mount a fever even with significant infection, which is why a high index of suspicion is needed.
Inability to bear weight
The patient cannot stand on the affected leg because of pain. Children may simply refuse to walk; adults describe a sudden lameness or sit/lie down to avoid using the leg.
Leg held in flexion and external rotation
The classic resting position. Flexing the hip and turning the foot outwards opens the joint capsule and reduces the pressure inside the joint. Any attempt to straighten the leg or rotate it inwards causes severe pain.
Warmth and swelling
The hip area may be warm to touch with visible swelling, although the deeper position of the hip joint can make these signs subtler than they would be in a more superficial joint like the knee.
Chronic post-infection pain
The late presentation. Months or years after an acute infection has been treated, the cartilage damage shows itself as chronic groin pain, stiffness, and limp. These patients are the ones who come to Mr Hussain for reconstruction.
What causes hip septic arthritis?
Most cases are caused by bacteria reaching the joint through the bloodstream (haematogenous spread) from a skin, dental, urinary, or respiratory infection. Direct inoculation from a wound or recent hip surgery is the other major route. Staphylococcus aureus accounts for around 50 to 65 per cent of adult cases. Patients with diabetes, immunosuppression, intravenous drug use, rheumatoid arthritis, or a prosthetic joint are at substantially higher risk.
Three mechanisms lead to bacteria entering the hip joint:
- Haematogenous spread. The most common route in both children and adults. Bacteria from a distant infection (skin abscess, urinary tract infection, pneumonia, dental abscess, endocarditis) reach the joint through the bloodstream. The hip's rich blood supply makes it particularly vulnerable.
- Direct inoculation. Bacteria enter the joint through penetrating trauma, intra-articular injection, or recent hip surgery. Prosthetic joint infections are a separate but related entity managed by specialist arthroplasty teams.
- Contiguous spread. From adjacent infections, particularly osteomyelitis of the femur or pelvis.
The microbiology varies by patient group:
- Staphylococcus aureus. The dominant cause in adults (around 50 to 65 per cent of cases). MRSA is now an increasing concern, particularly in healthcare-associated infection.
- Streptococcal species. Second most common in adults, particularly Group A streptococcus.
- Neisseria gonorrhoeae. A consideration in sexually active young adults, classically associated with disseminated gonococcal infection.
- Gram-negative organisms. Particularly in older patients, immunocompromised patients, and intravenous drug users.
- Salmonella. Specifically in patients with sickle cell disease.
- Mycobacterium tuberculosis. A more indolent presentation with chronic pain and stiffness rather than acute fever, increasingly seen in patients from endemic areas or those on immunosuppression.
The most important patient-side risk factors are intravenous drug use, diabetes mellitus, immunosuppression (steroids, biologics, chemotherapy, HIV), rheumatoid arthritis (both the disease and its treatment), prior hip surgery, prosthetic joint in situ, skin or soft tissue infection elsewhere, sickle cell disease, and extremes of age (under 5 and over 80).
How is hip septic arthritis diagnosed?
Acute hip septic arthritis is diagnosed by emergency joint aspiration (or arthroscopic/open biopsy) combined with blood tests showing raised inflammatory markers. Synovial fluid analysis showing white cell counts above 50,000 per cubic millimetre with over 75 per cent neutrophils strongly supports infection. Gram stain and culture confirm the organism. MRI is the most sensitive imaging test for early disease before plain X-ray changes appear.
Speed matters. From symptom onset to surgical washout, every hour counts. The diagnostic workup is therefore done in parallel with starting empirical antibiotics and planning emergency theatre.
Investigations used in acute hip septic arthritis:
- Inflammatory markers. CRP and ESR are usually significantly raised. White cell count is often raised but can be normal. Procalcitonin can support the diagnosis.
- Blood cultures. Taken before antibiotics where possible; positive in around 50 per cent of cases and helps target antibiotic therapy.
- Joint aspiration. The single most important test. Synovial fluid is sent for white cell count and differential, Gram stain, culture and sensitivity, and crystal analysis (to exclude crystal arthropathy). Hip aspiration is performed under ultrasound or fluoroscopic guidance.
- Synovial fluid white cell count. A count above 50,000 per cubic millimetre with over 75 per cent neutrophils strongly supports infection. Higher counts (over 100,000) are very specific.
- MRI. The most sensitive imaging test for early septic arthritis, showing joint effusion, synovial enhancement, and bone marrow oedema before any X-ray changes appear. Important for differentiating from non-infective causes.
- Plain X-rays. Often normal in the acute phase but show joint space narrowing, periarticular osteopenia, and bone erosion in established disease. The late post-infection X-ray shows the cartilage loss and deformity that drives chronic symptoms.
- Ultrasound. Identifies joint effusion quickly at the bedside and guides aspiration.
How is acute hip septic arthritis treated?
Acute hip septic arthritis is managed urgently on the NHS via A&E. The standard of care is emergency surgical washout (open or arthroscopic) combined with intravenous antibiotics for typically 4 to 6 weeks, starting empirically and then targeted once the culture identifies the organism. Patients are admitted to hospital throughout the acute phase. Private practice has no role in the acute care of this emergency.
The acute treatment pathway is well established and time-critical:
- Emergency hospital admission. Patients are admitted under the orthopaedic team, usually via A&E. Workup including bloods, joint aspiration, and imaging happens in the first few hours.
- Empirical antibiotics. Started immediately after blood and joint cultures are taken. Initial cover targets Staphylococcus aureus and streptococci; MRSA cover is added in high-risk patients. The 2023 OVIVA-style approach prefers intravenous therapy for the initial 2 weeks, then targeted therapy based on cultures.
- Surgical washout. The cornerstone of acute treatment. The joint is opened (or accessed arthroscopically), pus is drained, infected synovium is removed, and the joint is thoroughly washed out with saline. Sometimes repeat washouts are needed over 24 to 72 hours.
- Targeted antibiotic course. Once cultures identify the organism, antibiotics are narrowed and continued for typically 4 to 6 weeks, usually starting intravenously and switching to oral once inflammatory markers normalise and the patient is improving.
- Source control. Treatment of any other infection (skin, dental, urinary, endocarditis) that may have seeded the joint.
- Rehabilitation. Physiotherapy to maintain hip range of motion during recovery and to prevent stiffness.
Once infection is cleared, residual cartilage damage determines the long-term outcome. Some patients recover well and never need further surgery. Many develop chronic post-infection arthritis over the following months to years and eventually need reconstruction.
If you take prescribed medication, particularly blood-thinners or immunosuppressants, please review Mr Hussain's patient guide on medications to pause before hip or knee surgery as you approach any reconstructive surgical decision.
When should I consider hip replacement after septic arthritis?
Hip replacement reconstruction is considered once the infection has been definitively cleared and post-infection cartilage damage is causing significant chronic pain and disability. A safe interval between the last infection and reconstruction is generally 6 to 12 months at minimum, sometimes longer, with normal inflammatory markers and confirmed quiescence on imaging and aspiration.
The decision to reconstruct a previously infected hip is one of the more nuanced calls in hip surgery. Going too soon risks reactivating a dormant infection on the new implants (a periprosthetic joint infection). Going too late means the patient endures more years of pain than necessary and may develop secondary deformities.
Markers Mr Hussain looks for before recommending hip replacement after septic arthritis:
- At least 6 to 12 months since the last documented infection (often longer)
- Normalised inflammatory markers (CRP and ESR) on repeat blood tests
- Negative joint aspiration if any clinical doubt remains about quiescence
- Imaging showing established post-infection arthritis as the source of pain
- Chronic groin pain, stiffness, limp, and reduced walking distance that have not responded to physiotherapy and analgesia
- Significant impact on quality of life, work, and daily activities
- Patient understanding of the elevated risk of recurrent infection (around 4 to 10 per cent in published series for hip replacement after a previously infected joint)
The decision is collaborative. Mr Hussain works with microbiology, infectious diseases, and the patient to confirm infection clearance before committing to surgery.
Private consultations with Mr Hussain are available at the Royal Orthopaedic Hospital, Priory Hospital Edgbaston, and Harborne Hospital. See the private consultation and surgery fees page for pricing and recognised insurers, or book a consultation directly.
What surgical options are available for post-septic hip arthritis?
Total hip replacement, often as a two-stage procedure, is the standard reconstruction for chronic post-infection hip arthritis. The first stage clears any residual infected tissue and inserts an antibiotic-loaded cement spacer; the second stage inserts the definitive prosthesis once cultures confirm infection clearance. Single-stage reconstruction is reserved for highly selected cases where infection has been quiescent for many years. Hip resurfacing is generally not appropriate.
Reconstruction after septic arthritis carries higher infection and complication risk than primary hip replacement. The choice between single-stage and two-stage replacement is one of the central decisions and is made jointly with microbiology and infectious diseases input.
Two-Stage Total Hip Replacement
Two operations 6 to 12 weeks apart. The first stage clears any remaining infected tissue and inserts an antibiotic-loaded cement spacer in place of the hip joint. A course of intravenous and oral antibiotics follows. Once cultures and inflammatory markers confirm infection clearance, the second stage removes the spacer and inserts the definitive hip replacement.
- Standard treatment after a previously infected hip joint
- Lower risk of new prosthetic joint infection than single-stage
- Antibiotic-loaded spacer delivers high local drug concentration
- Total recovery 4 to 6 months across both stages
- Published recurrent infection rates around 4 to 10 per cent
Single-Stage Total Hip Replacement
One operation that combines clearance of any residual infected tissue with insertion of the definitive prosthesis. Considered only when the infection has been confirmed quiescent for many years, the organism is fully sensitive, the soft tissues are healthy, and the patient is medically optimised. Avoided when there is any residual sinus, suspected smouldering infection, or polymicrobial culture.
- Selected highly quiescent cases only
- Single operation, shorter overall recovery
- Higher risk of reinfection if any organism remains
- Requires fully sensitive organism and healthy soft tissues
- Decided jointly with microbiology and infectious diseases
Hip resurfacing is not appropriate for post-septic hip arthritis because the residual cartilage and bone damage, the higher reinfection risk, and the importance of long-term implant durability all favour total hip replacement. For background on the techniques and recovery, see Mr Hussain's patient guide on hip resurfacing versus total hip replacement.
How successful is hip replacement after septic arthritis?
Total hip replacement after a previously infected joint gives substantial pain relief and function, but with higher infection and complication rates than primary hip replacement for osteoarthritis. Published two-stage series report reinfection rates around 4 to 10 per cent and good functional outcomes in patients whose infection has been definitively cleared before reconstruction.
The historical view that a previously infected hip should never be replaced has been replaced by the modern two-stage protocol. Outcomes are good when patient selection, infection clearance, and surgical technique are all optimised. The dominant complication remains recurrent infection of the new prosthesis.
Expertise in complex hip reconstruction after infection in Birmingham
Consultant at the Royal Orthopaedic Hospital
Mr Hussain practises at the Royal Orthopaedic Hospital Birmingham, one of the largest specialist orthopaedic hospitals in Europe, alongside Priory Hospital Edgbaston and Harborne Hospital.
3,000+ arthroplasty cases
From a total of more than 5,000 procedures performed, giving the operative volume and case complexity required for consistently excellent outcomes. Read more about Mr Hussain's training and background.
British Hip Society Travelling Fellowship
Trained at ENDO-Klinik Hamburg under Professor Thorsten Gehrke and Professor Mustafa Citak, the international reference centre for complex hip surgery.
Both hip replacement and hip resurfacing
Many surgeons offer only one technique. Mr Hussain trained in both, allowing the choice to be tailored to the individual patient rather than to a single technique.
Doctify Outstanding Patient Experience 2024, 2025, and 2026
Awarded in three consecutive years, recognising consistently high patient-reported outcomes and communication.
4.98 out of 5 from verified reviews on Doctify. Outstanding Patient Experience Award 2024, 2025, and 2026.
Frequently asked questions about hip septic arthritis
For more questions about surgery, recovery, fees, and what to expect, see the full frequently asked questions page or read recent patient testimonials.