Periprostethetic Joint Infection

Question 1

Common organisms in periprosthetic joint infections

Answer 1

1. Staph aureus
2. Strep
3. Gram negative bacilli
   4.. Cutibacterium acnes (most common in shoulder)

Question 2

Early vs Delayed vs Late periprosthetic joint infection classification

Answer 2

Early: <3months post implant
Delayed: 3-24 moths post implant
Late: 2 years post implant

Question 3

Cause of hematogenous PJI

Answer 3

S aureus no initial local inflammatory signs, sepsis syndrome symptoms

Question 4

Chronic PJI s/s

Answer 4

Joint effusions, local chronic pain, implant loosening, sinus tract

Question 5

What would an arthrocentesis show in PJI early vs late infection WBC count

Answer 5

Early PJI >10,000 cells
Late PJI >3,000cells

Question 6

X ray, MRI, and CT results in PJI

Answer 6

X-ray: effusion
MRI/CT: Sinus tract, soft tissue infection, prosthetic loosening, bone erosion, effusion

Question 7

MSIS Criteria for PJI diagnosis

Answer 7

1 major and 4/6 mild criteria
Major: 2 + cx positive, or a sinus tract
Minor: Elevated CRP and ESR, elevated synovial fluid WBC, purulence in joint, positive histologic analysis, positive cx

Question 8

PJI treatment (consults, procedures, and ABX)

Answer 8

Consults: Ortho and PT
ABX: Empiric (rifampin plus naficillin plus vanco), Gram negative infections (Cipro or levaquin)
Procedures: Debridement and retain implant, one stage implant exchange, two stage implant exchange, or removal of implant w/o replacement