Periprosthetic Joint Infection — Debridement, Antibiotics and Implant Retention (DAIR)
ArthroplastyAdvancedCore Procedure
Periprosthetic Joint Infection — Debridement, Antibiotics and Implant Retention (DAIR)
Operative technique for DAIR in acute periprosthetic joint infection of the hip and knee — indications, patient selection, thorough debridement, modular exchange, culture protocol, antibiotic strategy and predictors of success versus failure
High-yield overview
Debridement, Antibiotics and Implant Retention for acute PJI of hip or knee | advanced
Surgical Imaging
Critical Decision Points and Failure Predictors in DAIR
Symptom Duration Threshold
The rule: Acute post-operative PJI less than 3 weeks of symptoms; acute haematogenous PJI less than 3 to 4 weeks of symptoms. Beyond these windows the biofilm is mature and DAIR success falls sharply.
The evidence: Multiple series show success greater than 70 percent when symptoms are less than 3 weeks versus less than 40 percent when greater than 6 weeks. The 3-week cut-off is the most widely accepted threshold for offering DAIR.
Well-Fixed Implant Requirement
The principle: The prosthesis must be mechanically stable at the bone-implant interface. Any radiographic or intraoperative evidence of loosening converts the procedure to a one-stage or two-stage revision.
The test: Intraoperative assessment of implant stability by attempting to move the femoral or tibial component with an instrument. If the implant moves or toggles, DAIR is abandoned and the case is converted to staged revision.
Sinus Tract — Absolute Contraindication
The fact: A draining sinus tract indicates chronic infection with a mature biofilm and external communication; DAIR success drops to approximately 30-40 percent.
The management: Any patient presenting with a sinus tract should be counselled for two-stage revision from the first consultation; attempting DAIR in this setting exposes the patient to an additional operation with low chance of success.
Organism Virulence and Susceptibility
The hierarchy: Streptococci and coagulase-negative staphylococci achieve the highest DAIR success (70-85 percent). MRSA, enterococci and polymicrobial infections have markedly lower retention rates (40-55 percent).
The implication: When preoperative aspiration or Gram stain suggests MRSA or a resistant Gram-negative, many surgeons proceed directly to two-stage revision rather than attempting DAIR, especially if other risk factors coexist.
Soft-Tissue Envelope Integrity
The requirement: The skin and subcutaneous tissues must be healthy enough to achieve primary wound closure over the debrided joint without tension. Previous multiple incisions, radiation, or severe scarring may preclude DAIR.
The assessment: If the planned incision would require flap coverage or the soft tissues are severely compromised, two-stage revision with soft-tissue optimisation is the safer plan.
Host Factors — McPherson Classification
The staging: McPherson host grade (A, B, C) and local extremity grade (1, 2, 3) strongly influence decision-making. Grade C hosts (immunocompromised, dialysis, active malignancy) have DAIR failure rates approaching 60-70 percent.
The practical rule: In a McPherson C host with additional risk factors, proceed directly to two-stage revision; the incremental morbidity of a failed DAIR followed by later revision outweighs the benefit of attempting implant retention.
Mnemonic
D.A.I.R.DAIR — Indications for Implant Retention
Mnemonic
T.E.C.H.TECHNIQUE — Critical Operative Steps
Mnemonic
F.A.I.L.FAILURE — Predictors of DAIR Failure
Surgical Indications
Absolute Indications for DAIR
Acute post-operative PJI with symptom onset less than 3 weeks after index arthroplasty
Acute haematogenous PJI with symptom duration less than 3 to 4 weeks
Well-fixed implant on preoperative radiographs and confirmed intraoperatively
Susceptible organism on preoperative aspiration or Gram stain (streptococcus, coagulase-negative staphylococcus, or known sensitive organism)
Intact soft-tissue envelope without sinus tract or severe scarring
Relative Indications
Early post-operative PJI (less than 6 weeks from index) with borderline symptom duration but favourable organism and host
Patient with significant medical comorbidity where two-stage revision carries prohibitive risk
Single early debridement performed elsewhere with retained implant and now referred for definitive management
Contraindications
Absolute:
Symptom duration greater than 3 to 4 weeks (biofilm maturation)
Radiographic or clinical evidence of implant loosening
Draining sinus tract
McPherson host grade C with multiple comorbidities where staged revision is safer
Known highly resistant organism (MRSA, VRE) in a patient with additional risk factors
Relative:
Previous failed DAIR attempt (success of second DAIR is less than 30 percent)
Immunocompromised host with additional local soft-tissue compromise
Polymicrobial infection in a diabetic or immunosuppressed patient
Evidence Base for DAIR
Success Rates and Predictors
Contemporary series report overall DAIR success (implant retention without further surgery for infection) of 55 to 75 percent at 2 years when strict selection criteria are applied. Success is highly dependent on timing, organism and the presence of a sinus tract.
A systematic review of 39 studies (928 knees, 677 hips) found pooled success of 67 percent when DAIR was performed within 3 weeks of symptom onset versus 42 percent when performed later. Staphylococcal infections (especially MRSA) and sinus tracts were independent predictors of failure on multivariate analysis.
Key Evidence
Evidence
Outcome of debridement and retention for prosthetic joint infection
Risk factors for failure of DAIR in periprosthetic joint infection
Level III
Odgaard A, Kristensen PW, Kappel A, et al. • J Bone Joint Surg Am
Evidence
Systematic review of debridement and implant retention for PJI
Level II
Kunutsor SK, Whitehouse MR, Blom AW, Beswick AD • J Bone Joint Surg Am
Relevant Surgical Anatomy for DAIR
Hip — Posterior Approach (Moore-Southern)
The posterior approach provides excellent exposure of the acetabulum and posterior femoral neck for debridement. Key structures at risk include the sciatic nerve (retracted and protected throughout), the inferior gluteal nerve to gluteus maximus, and the medial femoral circumflex artery (preserved if possible to maintain femoral head vascularity, although irrelevant in arthroplasty).
The posterior capsule is divided and tagged for later repair. The short external rotators are released and repaired at closure. In DAIR the goal is radical synovectomy of the entire capsule, including the anterior and inferior recesses that are reached only after the head is removed.
Knee — Medial Parapatellar Approach
The standard medial parapatellar arthrotomy provides access to the entire suprapatellar pouch, medial and lateral gutters, and posterior compartments once the tibial insert is removed. The infrapatellar fat pad is excised to improve visualisation of the anterior tibia-implant interface.
The posterior capsule is accessible only after the tibial insert is removed and the knee is hyperflexed with posterior retraction; this step is essential for complete debridement and is the reason modular exchange is mandatory.
Biofilm-Relevant Anatomy
Periprosthetic biofilm forms preferentially at the bone-implant interface, the modular taper junctions, and the polyethylene surface. The posterior recesses of both hip and knee are the most common sites of residual infection after inadequate DAIR because they cannot be visualised or debrided without removing the modular components.
Classification Systems Relevant to Decision-Making
McPherson Staging System
Host grade (A, B, C) and local extremity grade (1, 2, 3) are used to stratify risk. A McPherson C host with a grade 3 extremity (multiple previous incisions, radiation, severe scarring) has a DAIR failure rate exceeding 70 percent; most surgeons proceed directly to two-stage revision in this setting.
Tsukayama Classification
Type I (intraoperative positive culture), Type II (early post-operative less than 1 month), Type III (acute haematogenous), Type IV (chronic). DAIR is appropriate only for Type II and Type III with short symptom duration.
Positioning and Preparation
Patient position: Supine on a radiolucent table for both hip and knee. For the hip a bump under the ipsilateral sacrum facilitates posterior approach exposure. For the knee a sandbag under the ipsilateral buttock and a footrest allow the knee to be flexed to 90-120 degrees.
Anaesthesia: Regional (spinal or epidural) plus sedation is preferred to allow muscle relaxation and post-operative pain control. General anaesthesia is used when regional is contraindicated.
Tourniquet: For knee DAIR a thigh tourniquet is inflated to 300 mmHg after exsanguination; this reduces blood loss and improves visualisation during synovectomy. For hip DAIR no tourniquet is used.
Antibiotic timing: NO prophylactic antibiotics are given until all deep cultures have been obtained. This is the single most critical point of the procedure.
Imaging: Intraoperative fluoroscopy is available but rarely required unless there is doubt about implant fixation.
Step-by-Step Operative Technique — Knee DAIR
Step 1: Skin Incision and Arthrotomy
Use the previous midline incision, extending proximally and distally as needed for exposure. Raise full-thickness medial and lateral flaps. Perform a medial parapatellar arthrotomy, preserving the medial meniscus if present (rare in arthroplasty patients).
Step 2: Initial Joint Inspection and Cultures
Inspect the joint for purulence, synovitis, and loosening. Obtain the first set of cultures immediately: synovial fluid for cell count, Gram stain, culture and sensitivity; and tissue from the suprapatellar pouch, medial gutter, and lateral gutter. Use fresh instruments for each sample. Send five or more samples.
Clinical Pearl
Technical Tip: 'I label each culture tube with the exact anatomic site and the order in which it was taken. I never administer antibiotics until the fifth sample is in the container. If the Gram stain shows organisms, I still wait for the full set of cultures before giving antibiotics — the organism on Gram stain may not be the dominant pathogen.'
Dangers at this step
Administering antibiotics before all cultures are obtained — the most common and most consequential error in DAIR
Taking fewer than five samples or using the same instrument for multiple sites — risks false-negative cultures
Failing to record the exact site of each culture — makes later interpretation difficult if only some samples grow organisms
Step 3: Modular Component Removal
Remove the tibial insert (and patellar button if present) using the manufacturer-specific extraction tools. This step is mandatory. With the insert removed, the posterior compartments become accessible.
Step 4: Radical Synovectomy and Debridement
Perform a complete synovectomy using rongeurs, curettes and sharp dissection. Excise all inflamed synovium from the suprapatellar pouch, medial and lateral gutters, and the posterior capsule (now accessible). Remove any membrane from the bone-implant interface with curettes. Send additional tissue samples from the bone-implant interface and the liner membrane.
Irrigate the joint with a minimum of 9 litres of pulsed lavage saline. Adjunctive dilute betadine (0.35 percent) or hydrogen peroxide soaks are used by many surgeons for 3-5 minutes each, followed by further saline lavage.
Step 5: Assessment of Implant Stability
Attempt to move the femoral and tibial components with an instrument. Any toggle or movement indicates loosening; in this situation DAIR is abandoned and the case is converted to a one-stage or two-stage revision depending on bone loss and soft tissues.
Step 6: Modular Reimplantation
Irrigate the modular taper junctions thoroughly. Insert a new polyethylene tibial insert (and new patellar button if the original was removed). Use the same thickness or one size thicker if the joint was lax after debridement. Confirm stability and range of motion.
Step 7: Wound Closure
Close the arthrotomy with absorbable suture. Close subcutaneous tissue and skin in layers. Apply a compressive dressing and a knee immobiliser. No drain is routinely used.
Step-by-Step Operative Technique — Hip DAIR (Posterior Approach)
Step 1: Positioning and Incision
Lateral decubitus position. Use the previous posterior incision, extending proximally along the gluteus maximus and distally along the femur as needed.
Step 2: Exposure and Cultures
Split the gluteus maximus, identify and protect the sciatic nerve. Perform a posterior capsulotomy and tag the capsule. Dislocate the hip. Obtain five deep cultures before any antibiotics.
Step 3: Modular Exchange and Debridement
Remove the femoral head and acetabular liner. Perform radical synovectomy of the entire capsule, including the anterior and inferior recesses. Curette the bone-implant interfaces. Irrigate with 9 litres pulsed lavage plus adjunctive agents.
Step 4: Stability Assessment and Reimplantation
Confirm implant stability. Irrigate taper junctions. Insert new head and liner. Reduce the hip and confirm stability and leg length.
Step 5: Posterior Repair and Closure
Repair the posterior capsule and short external rotators to the greater trochanter. Close in layers. Apply a compressive dressing.
Clinical Pearl
Technical Tip: 'After the head and liner are out I spend at least 15 minutes on synovectomy alone. I use a headlamp and loupes. Every recess must be cleared — the inferior acetabular recess and the posterior femoral recess are the two most commonly missed areas. I send a final set of cultures from these posterior recesses after I think I have finished debriding.'
Dangers at this step
Leaving the original liner in situ — the posterior recesses cannot be accessed or debrided adequately
Inadequate volume of irrigation — less than 6 litres is associated with higher failure rates in registry data
Failure to repair the posterior capsule — increases dislocation risk after DAIR
Sciatic nerve injury during retraction — always identify and protect the nerve throughout
Intraoperative and Early Complications
Persistent Infection / DAIR Failure
The most common complication. Defined as recurrent infection requiring further surgery or lifelong suppression. Overall rate 25-45 percent when strict selection criteria are used.
Risk factors:
Symptom duration greater than 3 weeks
MRSA or resistant organism
Sinus tract
McPherson C host
Incomplete modular exchange
Management: When DAIR fails, the patient proceeds to two-stage revision. A second DAIR attempt has success less than 30 percent and is rarely indicated.
Wound Complications
Dehiscence, prolonged drainage, and superficial infection occur in 8-15 percent of cases, higher in obese patients and those with previous multiple incisions.
Prevention: Meticulous layered closure, negative-pressure wound therapy in high-risk wounds, and early mobilisation.
Management: Superficial dehiscence may be managed with local care and antibiotics; deep infection requires return to theatre for washout and consideration of staged revision.
Dislocation (Hip DAIR)
Occurs in 3-8 percent after posterior-approach DAIR, higher than primary THA because of capsular violation and muscle damage from infection.
Prevention: Meticulous posterior repair, appropriate head size (36 mm or larger), and patient education on dislocation precautions.
Late Complications
Aseptic Loosening
The debridement and modular exchange can compromise implant fixation over time. Aseptic loosening requiring revision occurs in 5-10 percent of successful DAIR cases at 5-10 years.
Antibiotic-Related Complications
Prolonged intravenous and oral antibiotic therapy carries risks of nephrotoxicity, hepatotoxicity, Clostridium difficile colitis, and peripheral neuropathy (especially with fluoroquinolones). Monitoring of renal and liver function is mandatory.
Immediate Post-operative Protocol
Day 0-3
Intravenous antibiotics commence after the final culture is obtained in theatre; the initial regimen is vancomycin plus a third-generation cephalosporin or piperacillin-tazobactam pending culture results.
Drain (if used) removed at 24-48 hours.
Mobilisation with full weight-bearing as tolerated from day 1 (knee) or day 2 (hip).
Wound review at 48 hours; negative-pressure dressing applied if drainage persists.
Week 1-6
Tailor antibiotics to culture results once available (usually 48-72 hours). Add biofilm-active agents: rifampicin 300 mg twice daily for staphylococci (after confirming susceptibility and after wound is dry); ciprofloxacin or levofloxacin for Gram-negative organisms.
Total intravenous duration 6 weeks, followed by oral step-down for 3-6 months (or indefinite suppression in selected high-risk cases).
Weekly wound review; CRP and ESR at 2, 4 and 6 weeks.
Month 3-6
Oral antibiotics continued until CRP normalises and remains normal for 4 weeks off therapy (in patients planned for finite course).
Clinical and radiographic review at 3 and 6 months.
If infection recurs, proceed to two-stage revision.
Antibiotic Strategy Summary
Methicillin-sensitive Staphylococcus
Intravenous (6 weeks)
Flucloxacillin or cefazolin
Oral Step-Down (3-6 months)
Trimethoprim-sulfamethoxazole or doxycycline
Biofilm Agent
Rifampicin
MRSA
Intravenous (6 weeks)
Vancomycin (or daptomycin)
Oral Step-Down (3-6 months)
Linezolid or trimethoprim-sulfamethoxazole
Biofilm Agent
Rifampicin
Streptococcus
Intravenous (6 weeks)
Penicillin or ceftriaxone
Oral Step-Down (3-6 months)
Amoxicillin
Biofilm Agent
None routinely
Gram-negative (susceptible)
Intravenous (6 weeks)
Ceftriaxone or piperacillin-tazobactam
Oral Step-Down (3-6 months)
Ciprofloxacin or levofloxacin
Biofilm Agent
Fluoroquinolone
Culture-negative
Intravenous (6 weeks)
Vancomycin + ceftriaxone
Oral Step-Down (3-6 months)
Trimethoprim-sulfamethoxazole + ciprofloxacin
Biofilm Agent
Rifampicin + fluoroquinolone
Organism
Intravenous (6 weeks)
Oral Step-Down (3-6 months)
Biofilm Agent
Methicillin-sensitive Staphylococcus
Flucloxacillin or cefazolin
Trimethoprim-sulfamethoxazole or doxycycline
Rifampicin
MRSA
Vancomycin (or daptomycin)
Linezolid or trimethoprim-sulfamethoxazole
Rifampicin
Streptococcus
Penicillin or ceftriaxone
Amoxicillin
None routinely
Gram-negative (susceptible)
Ceftriaxone or piperacillin-tazobactam
Ciprofloxacin or levofloxacin
Fluoroquinolone
Culture-negative
Vancomycin + ceftriaxone
Trimethoprim-sulfamethoxazole + ciprofloxacin
Rifampicin + fluoroquinolone
When to Abandon DAIR for Staged Revision
Intraoperative findings that mandate conversion:
Implant loosening
Severe bone loss precluding stable reimplantation of modular components
Inability to achieve primary soft-tissue closure
Unexpected finding of chronic-appearing membrane or sinus tract not appreciated preoperatively
Post-operative findings that prompt early conversion:
Persistent elevation of CRP beyond 6 weeks despite appropriate antibiotics
Recurrent wound drainage after 3 weeks
Positive cultures from more than two sites growing a resistant organism not covered by current regimen
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
Viva scenarioAdvanced
Clinical prompt
“A 68-year-old man presents 18 days after primary total knee arthroplasty with increasing pain, swelling and warmth. Aspiration shows 45,000 white cells with 92 percent neutrophils and Gram-positive cocci in clusters on stain. He has no sinus tract and the implant appears well-fixed on radiographs. How do you proceed?”
Practical approach
This is an acute post-operative PJI within the 3-week window with a susceptible-appearing organism and a well-fixed implant — classic indication for DAIR.
**Pre-operative plan**: I would proceed to urgent DAIR within 24 hours. I would obtain full blood count, CRP, ESR, and ensure the organism is identified as thoroughly as possible from the aspirate (culture and sensitivity). I would discuss with infectious diseases the likely initial antibiotic regimen (vancomycin plus a cephalosporin) but would not commence antibiotics until intraoperative cultures are obtained.
**Operative plan**: Medial parapatellar approach through the existing incision. Obtain a minimum of five deep cultures with fresh instruments before any antibiotic administration. Remove the tibial insert (mandatory modular exchange) to access the posterior compartments. Perform radical synovectomy of the entire suprapatellar pouch, gutters and posterior capsule. Irrigate with 9 litres pulsed lavage plus dilute betadine soaks. Confirm implant stability. Insert a new tibial component of appropriate thickness. Close in layers.
**Post-operative**: Intravenous antibiotics for 6 weeks followed by oral step-down for 3-6 months with rifampicin added once the organism is confirmed susceptible. Weekly CRP monitoring. If CRP fails to normalise or symptoms recur, convert to two-stage revision.
Viva scenarioAdvanced
Clinical prompt
“You are performing a DAIR on a 72-year-old woman with acute haematogenous PJI of the hip 11 days after symptom onset. Intraoperatively you find a well-fixed stem and cup but discover a small sinus tract communicating with the greater trochanter that was not appreciated on preoperative examination. What do you do?”
Practical approach
The unexpected finding of a sinus tract changes the prognosis dramatically and converts this from a favourable DAIR candidate to a high-risk case.
**Intraoperative decision**: I would complete the thorough debridement and modular exchange as planned, obtain all cultures, and close the wound. However, I would counsel the patient immediately post-operatively that the presence of a sinus tract reduces the probability of successful implant retention to approximately 35-40 percent and that a two-stage revision may ultimately be required.
**Antibiotic plan**: I would treat this as a DAIR attempt but with a low threshold for early conversion. The organism (once identified) would dictate the regimen, with biofilm-active agents added. CRP would be monitored weekly.
**Follow-up strategy**: If the CRP fails to trend down by 4 weeks or if wound drainage persists beyond 3 weeks, I would proceed to two-stage revision rather than attempting a second DAIR. A second DAIR in the presence of a sinus tract has success below 25 percent.
Viva scenarioAdvanced
Clinical prompt
“A 65-year-old diabetic man undergoes DAIR for acute post-operative knee PJI. Cultures grow methicillin-sensitive Staphylococcus aureus. At 8 weeks the CRP is normal and the wound is healed. How long do you continue antibiotics and what is your surveillance plan?”
Practical approach
This is a favourable organism (MSSA) in a patient who has responded well clinically. Antibiotic duration and surveillance follow evidence-based protocols for DAIR.
**Antibiotic plan**: Complete the 6-week intravenous course (flucloxacillin or cefazolin). Add rifampicin 300 mg twice daily once the wound is dry and the organism is confirmed susceptible. Transition to oral trimethoprim-sulfamethoxazole or doxycycline plus rifampicin for a further 3-6 months.
**Duration decision**: At 3 months I would stop antibiotics if the CRP has remained normal for 4 weeks and there are no clinical signs of infection. Some surgeons continue suppression for 6-12 months in diabetic patients; I would discuss the risks and benefits of finite versus indefinite suppression with the patient and infectious diseases.
**Surveillance**: CRP and ESR at 3, 6 and 12 months, then annually for 5 years. Any rise in inflammatory markers or return of symptoms prompts repeat aspiration and consideration of two-stage revision.
Exam day cheat sheet
DAIR for Periprosthetic Joint Infection — Exam Day Summary
References
Evidence
Outcome of debridement and retention for prosthetic joint infection