PJI (Complete) Flashcards

1
Q

What is the preoperative workup of a suspected PJI?

[IDSA guidelines]

A
  1. 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
  1. Physical exam
    * Swelling, Erythema, Drainage, Sinus tract
  2. Obtain OR note for date and type of implants
  3. ESR/CRP
  4. Blood culture if fever or acute onset of symptoms
  5. Radiographs
  6. Joint arthrocentesis
    * Cell count, cell differential, gram stain, culture and sensitivity, crystals
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2
Q

What is the treatment for acute infected prosthesis (TKA/THA)

(<30 days postop or <3 weeks of symptoms from hematogenous infection):

A

Single Stage Revision

  1. 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)
  1. Administration of 6 weeks of IV antibiotics
    * Possible 3-6 months of oral antibiotics following
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3
Q

What is the management of chronic infected prosthesis (TKA/THA)?

A

2 Stage Revision:

  1. 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)
  1. 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
  1. 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
  1. Administration of antibiotics until cultures negative
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4
Q

What are the risk factors for PJI in TKA?

[JAAOS 2015;23:356-364]

A

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
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5
Q

What is the 2018 Definition of PJI?

[MSIS/Parvizi - The Journal of Arthroplasty 33 (2018) 1309e1314]

A

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
      1. 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
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6
Q

What are the thresholds for the minor diagnostic criteria in the 2018 MSIS/Parvizi definition of PJI?

[The Journal of Arthroplasty 33 (2018) 1309e1314]

A
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7
Q

What are the incidences of deep infection associated with primary TKA and THA?

[JAAOS 2014;22:153-164]

A
  1. TKA = 1-2%
  2. THA = 0.3-2.9%
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8
Q

In what clinical setting has a single stage revision been shown to be most successful?

[JAAOS 2014;22:153-164]

A
  1. THA rather than TKA
  2. Causative bacteria is known and gram positive
  3. Not polymicrobial
  4. Antibiotic therapy tailored to the causative bacteria is administered for 12 weeks
  5. Patient factors are optimal (adequate soft tissue and bone stock, no immunosuppression or significant comorbidities)
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9
Q

Describe a two-stage revision for PJI?

[JAAOS 2014;22:153-164]

A

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
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10
Q

What considerations must be taken for antibiotic cement?

[JAAOS 2014;22:153-164]

A
  1. Commercially available antibiotic cement is meant for prophylaxis not active infection (inadequate dose)
  2. 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
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11
Q

What are the reported dose ranges per 40g bag of bone cement for gentamicin, tobramycin and vancomycin?

[JAAOS 2014;22:153-164]

A
  1. Gentamicin = 2-5g
  2. Tobramycin = 2.4-9.6g
  3. Vancomycin = 3-9g

Target 3g vanco and/or 3.6g tobramycin in 40g cement

  • Vanco = 1g/vial, Tobra = 1.2g/vial
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12
Q

What is the recommended antibiotics for bone cement if the organism is unknown?

[JAAOS 2014;22:153-164]

A

4g Vancomycin + 4g ceftazidime per 40g bag

  • A. Vancomycin = gram positive coverage and MRSA
  • B. Ceftazidime = gram positive, gram negative, pseudomonas
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13
Q

When would a static cement spacer be chosen over a dynamic cement spacer?

[JAAOS 2014;22:153-164]

A
  1. Generally, dynamic preferred
  2. 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
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14
Q

What options are available for hip cement spacers in two stage revision?

[JAAOS 2014;22:153-164]

A

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
  1. Prefabricated
    * a.Disadvantages – limited sizes, predetermined antibiotic and dose (not tailored to patient)
  2. Metal-on-polyethylene
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15
Q

What is the preferred hip cement spacer?

[JAAOS 2014;22:153-164]

A
  1. Custom molded press-fit into the femoral canal
  2. Plus an antibiotic cement shelf created with 6.5mm cancellous screws into the ilium to reduce risk of dislocation
  3. +/- large frag compression plate coated with antibiotics secured to lateral femur with cerclage in settings of ETO or proximal femoral bone loss
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16
Q

What are options available for knee cement spacers?

[JAAOS 2014;22:153-164]

A

1.Static cement spacer

  • a.Rush rods placed through the cement into the intramedullary canal of the femur and tibia
  • b.Advantages – preserves joint space, provides initial stability, period of soft tissue rest

2.Dynamic cement spacer

  • a.Cement on cement
  • b.Cement on poly
  • c.Metal on poly
    • i.Advantages – custom antibiotics, accurate component sizing, improved wear, improved function between first and second stage
  • d.Advantages – similar infection eradication rates compared to static, higher ROM and knee function scores
17
Q

What is the recommended antibiotic course after the first stage?

[JAAOS 2014;22:153-164]

A
  1. 6-8 weeks of IV antibiotics
  2. Consider 3-4 months if:
  • a.Immunocompromised
  • b.Large draining sinus present
  • c.Poor soft tissue envelope
  • d.Virulent organism (eg. MRSA)
  1. 2 weeks prior to second stage antibiotics are held (‘antibiotic holiday’)
18
Q

When is chronic suppressive antibiotics considered?

[JAAOS 2014;22:153-164]

A
  1. Patient is medically unfit for surgery
  2. Significant morbidity would result from revision due to complex case
  3. Inability to reconstruct due to complexity
  4. Infecting organism is susceptible to an oral antibiotic that is relatively nontoxic and tolerated by the patient
19
Q

When is it safe to proceed with the second stage reimplantation?

[JAAOS 2014;22:153-164]

A

1.ESR and CRP decline

  • a.Do not have to return to normal, no cutoff values
  • b.Remain down after antibiotic holiday

2.Absence of clinical signs of infection

20
Q

When should joint aspiration be performed prior to second stage reimplantation?

[JAAOS 2014;22:153-164]

A
  1. Not performed routinely (low sensitivity)
  2. Perform when infection suspected (high specificity)
21
Q

At the time of second stage reimplantation what is the role of frozen section analysis?

[JAAOS 2014;22:153-164]

A
  1. If frozen section >5PMNs per high powered field for any specimen = infected
    * a.Repeat first stage
  2. If frozen section <5 PMNs per high powered field = not infected
    * a.Proceed to reimplantation
22
Q

When can a I&D and liner exchange be considered?

[Infect Dis Clin N Am 31 (2017) 237–252][IDSA guidelines]

A
  1. Hematogenous infection with <3 weeks of symptoms
  2. Early postoperative infection <30 days after surgery
23
Q

What is the COA consensus statement (2016) on antibiotic use when having dental procedures?

A
  1. Patients should not be exposed to the adverse effects of antibiotics when there is no evidence that such prophylaxis is of any benefit.
  2. Routine antibiotic prophylaxis is not indicated for dental patients with total joint replacements, nor for patients with orthopaedic pins, plates and screws.
  3. Patients should be in optimal oral health prior to having total joint replacement and should maintain good oral hygiene and oral health following surgery. Orofacial infections in all patients, including those with total joint prostheses, should be treated to eliminate the source of infection and prevent its spread.