PJI (Complete) Flashcards
What is the preoperative workup of a suspected PJI?
[IDSA guidelines]
- History
- Acute onset of pain
- Chronic pain since surgery
- Wound healing problems, drainage, superficial or deep infection
- Systemic symptoms (fever, chills, etc.)
- Prior surgeries on affected joint
- Physical exam
* Swelling, Erythema, Drainage, Sinus tract - Obtain OR note for date and type of implants
- ESR/CRP
- Blood culture if fever or acute onset of symptoms
- Radiographs
- Joint arthrocentesis
* Cell count, cell differential, gram stain, culture and sensitivity, crystals
What is the treatment for acute infected prosthesis (TKA/THA)
(<30 days postop or <3 weeks of symptoms from hematogenous infection):
Single Stage Revision
- DAIR – debridement, antibiotics, irrigation and retention of implants
- A. Utilize previous approach
- B. Multiple tissue samples for culture (3-6)
- C. Extensive debridement of all devitalized soft tissue and bone
- D. Synovectomy
- E. Exchange of modular components
- i. Liner, modular head
- F. Low pressure irrigation (6-9L)
- Administration of 6 weeks of IV antibiotics
* Possible 3-6 months of oral antibiotics following
What is the management of chronic infected prosthesis (TKA/THA)?
2 Stage Revision:
- First stage
- A. Utilize previous approach
- B. Remove all implants
- C. Multiple tissue samples for culture (3-6)
- D. Extensive debridement of all devitalized soft tissue and bone
- E. Synovectomy
- F. Reaming of intramedullary canals
- G. Low pressure irrigation (6-9L)
- H. Insert static or dynamic antibiotic spacer dependent on patient factors (soft tissue, bone loss, previous failed dynamic spacer)
- Administration of 6-8 weeks of IV antibiotics based on sensitivities (consult ID)
- Consider 3-4 months if immunocompromised, poor soft tissue coverage, sinus tract or virulent organism
- 2 week antibiotic holiday prior to proceeding to second stage
- i. ESR/CRP remain stable and no clinical signs of infection
- Second stage
- A. Remove antibiotic cement spacer
- B. Send tissue for frozen section
- i. If <5 PMNs per high powered field for all specimens proceed with second stage
- ii. If >5 PMNs per high powered field for any specimen repeat first stage
- C. Irrigation and debridement
- D. Reconstruction with revision components
- Administration of antibiotics until cultures negative
What are the risk factors for PJI in TKA?
[JAAOS 2015;23:356-364]
1.Preoperative
- a.Malnutrition
- b.Diabetes
- c.Obesity
- d.Male
- e.Posttraumatic arthritis
- f.Inflammatory arthritis
- g.Colonization with MRSA
- h.Prophylactic antibiotics
2.Intraoperative
- a.Skin prep
- b.Longer surgical time
- c.Antibiotic impregnated cement
- d.OR configuration and traffic
- e.Wound closure
- f.Frequent glove changes
3. Postoperative - a.Retention of foley catheter >1 day
- b.Blood transfusions
- c.Prolonged wound drainage
- d.Dental procedures
What is the 2018 Definition of PJI?
[MSIS/Parvizi - The Journal of Arthroplasty 33 (2018) 1309e1314]
1.Major Criteria
- Two positive cultures of the same organism
- Sinus tract with evidence of communication to the joint or visualization of the prosthesis
- DECISION
- At least one of the following = infected
2.Minor Criteria
- SERUM
- Elevated CRP OR D-Dimer - Score 2
- Elevated ESR - Score 1
- SYNOVIAL
- Elevated synovial WBC count or LE - Score 3
- Positive alpha-defensin - Score 3
- Elevated synovial PMN% - Score 2
- Elevated synovial CRP - Score 1
- DECISION
- ≥6 = infected
- 2-5 = possibly infected
- For patients with inconclusive minor criteria, operative criteria can also be used to fulfill definition for PJI.
- 0-1 = not infected
- Inconclusive preop score OR dry tap
- Positive histology - Score 3
- Positive purulence - Score 3
- Single positive culture - Score 2
- DECISION
- ≥6 = infected
- 4-5 = inconclusive
- Consider further molecular diagnostics such as next-generation sequencing
- ≤3 = not infected
What are the thresholds for the minor diagnostic criteria in the 2018 MSIS/Parvizi definition of PJI?
[The Journal of Arthroplasty 33 (2018) 1309e1314]
What are the incidences of deep infection associated with primary TKA and THA?
[JAAOS 2014;22:153-164]
- TKA = 1-2%
- THA = 0.3-2.9%
In what clinical setting has a single stage revision been shown to be most successful?
[JAAOS 2014;22:153-164]
- THA rather than TKA
- Causative bacteria is known and gram positive
- Not polymicrobial
- Antibiotic therapy tailored to the causative bacteria is administered for 12 weeks
- Patient factors are optimal (adequate soft tissue and bone stock, no immunosuppression or significant comorbidities)
Describe a two-stage revision for PJI?
[JAAOS 2014;22:153-164]
1.First stage
- a.Removal all implants and foreign material
- b.Extensive debridement
- i.All nonviable soft tissues and bone, synovectomy, irrigation, and reaming of the medullary canals
- c.Antibiotic cement spacer
- d.Antibiotics
2.Second stage
- a.Performed once antibiotics complete, wound healed and infection eradicated
- b. Remove antibiotic cement spacer
- c. Irrigation and debridement
- d. Reconstruction with revision components
What considerations must be taken for antibiotic cement?
[JAAOS 2014;22:153-164]
- Commercially available antibiotic cement is meant for prophylaxis not active infection (inadequate dose)
- Antibiotics added to cement must have the following features:
- a.Water soluble
- b.Thermodynamically (heat) stable [vanco, gentamycin, tobramycin]
- c.Bactericidal
- d.Released gradually over an appropriate period of time
- e.Evoke minimal local inflammatory reaction
- f. Selected based on likely pathogens and culture sensitivites
What are the reported dose ranges per 40g bag of bone cement for gentamicin, tobramycin and vancomycin?
[JAAOS 2014;22:153-164]
- Gentamicin = 2-5g
- Tobramycin = 2.4-9.6g
- Vancomycin = 3-9g
Target 3g vanco and/or 3.6g tobramycin in 40g cement
- Vanco = 1g/vial, Tobra = 1.2g/vial
What is the recommended antibiotics for bone cement if the organism is unknown?
[JAAOS 2014;22:153-164]
4g Vancomycin + 4g ceftazidime per 40g bag
- A. Vancomycin = gram positive coverage and MRSA
- B. Ceftazidime = gram positive, gram negative, pseudomonas
When would a static cement spacer be chosen over a dynamic cement spacer?
[JAAOS 2014;22:153-164]
- Generally, dynamic preferred
- Static spacer indicated when:
- a.Soft-tissue is compromised
- b.Massive bone loss and stability can not be achieved with a dynamic spacer
- c.Dynamic spacer fails to eradicate infection
What options are available for hip cement spacers in two stage revision?
[JAAOS 2014;22:153-164]
1.Hand-made
- a.Advantages – low cost, easy to fashion in OR
- b.Disadvantages – inconsistencies in design leading to failure and dislocation
2.Custom molded
- a.Advantages – more consistent geometry compared to hand-made
- b.Disadvantages – limited by mold size, risk of spacer failure
- Prefabricated
* a.Disadvantages – limited sizes, predetermined antibiotic and dose (not tailored to patient) - Metal-on-polyethylene
What is the preferred hip cement spacer?
[JAAOS 2014;22:153-164]
- Custom molded press-fit into the femoral canal
- Plus an antibiotic cement shelf created with 6.5mm cancellous screws into the ilium to reduce risk of dislocation
- +/- large frag compression plate coated with antibiotics secured to lateral femur with cerclage in settings of ETO or proximal femoral bone loss
