Prevention and Treatment of Infection in Knee and Hip Arthroplasty

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Prevention and Management of
Infected Joint Replacements
Jim Nairus, MD
New England Baptist Hospital
Financial Disclosure
I have received no funding from any
sources related to topics of this discussion
Three Major Sources of Infection
Patient
Surgical Team
Hospital Environment
Incidence
With Prophylaxis


0.5% to 2% with primary joint replacements
3-5% after revision joint replacements
Incidence lowered with perioperative
antibiotics
Controversial: Antibiotic Cement, UV
lights, space suits, laminar flow, less traffic
in operating room
Ramifications
Most devastating complication
High cost to hospital and patient

$15,000 to $30,000 loss to hospital per
patient
Barrack CORR 1996


3 mos to 1 year out of life
Very debilitating
Organisms
75% caused by staph

Staph epidermidis (non-aureus) most
common, followed by staph aureus and then
MRSA
10% strep usually viridens
10% gram negatives

Not as bad as previously thought
5% Others
Optimizing Patient
Lose weight
 Obesity with increased infection rate due to
longer surgical time, greater surgical
dissection, and high calorie poor nutrition diet
 Namba et al in 2005 showed obese patients
6.7% higher risk of infection
Control perioperative blood sugar in diabetics
Stop TNF Alpha Antagonists one dosing cycle
prior to surgery
Optimizing Patient
Pre-operative staph screening
 Molecular DNA studies have shown majority of
infecting strains are part of resident’s nasal flora
 PCR test for staph aureus and MRSA
 Nasal Bactroban if nares positive for MSSA or MRSA
Rao in 2008 showed reduced infections from 2.6%
to 1.5%
 Vancomycin and isolation precautions for MRSA
Antibiotic Prophylaxis
The Most Important Factor in Lowering Infections

Charnley lowered infection rate from 7% to 0.5%
Want highest blood concentration of antibiotic at time of
incision
Should be completed within 20 to 60 minutes prior to
incision
Should be repeated if surgery lasts more than 2 hours or
when patient loses more that 30% of blood volume
(1.5L)
Should be continued for 24 hours post-op
 No evidence of efficacy beyond 24 hours
Kefzol
Considered by many to be best
Bactericidal
Excellent tissue penetration, rapid (within
minutes) and good bioavailability
Broad spectrum (active against all skin flora
including gram negatives)
Disadvantage: does not cover MRSA or MRSE
Patients weighing greater than 80 kg should get
2 gr
Vancomycin
Should be administered to patients colonized
with MRSA or MRSE
Not best for MSSA
Disadvantage: needs to be administered over 1
to 1.5 hours and is oftentimes not timed correctly
Does not cover any gram negatives
Probably best for revisions
 JBJS ’04 – 30% of pos revision cultures
resistant to Kefzol
Penicillin Allergic Patients
5% of individuals allergic to penicillin are
allergic to cephalsporins (Kefzol)
Can give test dose of Kefzol


Especially if allergy is rash
Probably not with anaphylaxis or swelling
Should never give Clindamycin

Bacterostatic only
Consider Vancomycn
Kefzol and Vancomycin
Covers almost all organisms
Controversial because of development of
resistance especially to Vancomycin
Consider in high risk patients

Obesity, revisions, anemia, diabetes,
smokers, immunocompromised, prior
surgeries
Antibiotic Impregnated Cement
Advantages:

Lower incidence of infection
Norwegian Arthroplasty Registry (10,611 THR’s)
and Swedish Joint Registry (92,675 THR’s)
Disadvantages



Higher incidence resistant organisms
(Swedish Registry, Kendall JArthrop ’96)
Structural support (can use up to 2g per 40g
bag of cement)
Cost
Cost
Bag of cement approximately $60
Tobramycin cement as high as $300
Usually use two bags of cement
Adding Vancomycin to cement only costs
extra $10 to $20


Unfortunately have to mix at time of surgery
Costs time and ?sterility
Chiu et al, JBJS 2001
Prospective randomized study (340
TKR’s)
0 infections in atbx cement group and 5
(3.1%) infections in non-atbx group
Chiu et al, JBJS 2002 showed 5 cases of
infection were all in diabetics
Personal Preference
Tobramycin cement in all revisions not
replanted for infection
Vancomycin cement in all replant TJR’s
after infection
Tobramycin cement in TJR’s in diabetics,
rheumatoid’s, UTI’s, and
immunocompromised
Non-antibiotic cement in all others
Operating Room Environment
Multiple studies show contamination from people
present in OR (surgical team, anesthesia team,
patient)
People shed from 1,000 to 10,000 bacteria per
minute
Bacterial contamination not shown to be
prevented by surgical gowns although switching
from cloth to plastic gowns lessened bacterial
shed
Laminar Flow and Ventilated Suits
Swedish registry > 150,000 TJR’s
No decrease risk for infection with
ventilated suits or laminar flow as long
as prophylactic antibiotics used
New Zealand Registry showed higher
incidence of infection with both laminar
flow and space suits
Operating Room
Ritter has shown that number of bacteria
cultured at surgical site and on surgical
table directly proportional to number of
people in operating room
Number of times door opens directly
proportional to number of bacteria present
Avoid Overuse of Antibiotics
Wound drainage
Temperatures
Erythema
Can mask deep infection where antibiotics are
not helpful and change classification from acute
to chronic infection
Persistent Wound Drainage
Established Knee Infections
 17-50% have persistent wound drainage beyond 3-4
days
Krakow ’93 J Arthroplasty
 8/597 (1.3%) – Persistent Drainage
 All taken back to OR
 Average 12.5 days post-op
 Two (25%) had positive deep cultures
 None developed clinical infection
 Conclusions:
Persistent drainage = impending infection
Aggressive operative treatment recommended
Etiology
½ infections introduced at the time of
surgery or immediately post-op
1/3 are hematogenous
Remainder not sure
Classification
All based on the duration of signs and
symptoms

Acute
Post-operative

Within 4 weeks of surgery
Hematogenous


Within 4 weeks of symptoms
Chronic
More than 4 weeks from surgery or symptoms
Diagnosis
Labs
X-rays
Bone scan
Aspiration
Intra-op Frozen section
Intra-op culture
Labs
CBC
 Rarely positive
Sed rate
 Very sensitive but not specific
 Usually > 35
 Takes 1 yr to return to normal after surgery
C-reactive Protein
 Peaks 48 hrs post-op and declines to normal
2-3 weeks later
 Used to monitor treatment
 Can be elevated with CAD
Plain Radiographs
Only positive with
osteolysis in chronic
infections
Bone scan
Positive with aseptic loosening and
infection
Need tagged WBC scan to be more
specific

May not be reliable
Aspiration
False positive in 015%
False negative when
organisms have poor
vitality
Should be selective
and use with labs
Get cell count with it
Cell Count
Cut-off value shown to be 1,100 to 3,000
WBC




Lower glucose than blood glucose
Differential with 60-80% Neutrophils
Definitely not the 50,000 WBC for native knee
Higher value for recently operated on knee
With these parameters shown to be very
good test
Intra-op Frozen Section
Intra-op Gram stain

Poor sensitivity and poor predictive value
Morgan JBJS 2009
Can get false positives from debris
Using 5 PMN’s/PHPF 84% sensitive and
96% specific

Lonner suggests 10 PMN’s/PHPF
Should always use when replanting after
infection or when highly suspicious
Intra-op Cultures
Gold standard
Send 5 samples (2/5 for positive)
6-13% false positive
Correlate with pathology
Treatment
Based on Classification
Need to know duration of symptoms
Need to do in a timely fashion
Acute Early Post-op
Surgical debridement with change of
anything easily removable
Then treat with at least 6 wks of IV
antibiotics

10 to 50% success rate
No role for arthroscopy
Late Chronic
Resection with or without antibiotic cement
spacer
Staged revision with frozen section after normal
labs and aspiration (80% to 96% successful)
Recurrence rate 10%
Use antibiotic cement in knees
1 stage exchange not as successful

58% to 83%
Acute Hematogenous
Surgical debridement and change easily
removable parts and 6 wks IV atbx
Surgical emergency
80% success rate if done within one week
of onset of symptoms
10 to 50% success rate if done within four
weeks of symptoms
Surgical Debridement and
Component Retention
Results improve with urgency of procedure
Need one-year or lifetime oral suppressive
antibiotics after 6 wks IV antibiotics
1 yr failure rate 54%
2 yr failure rate 69%
Girldestone Resection Arthroplasty
For Poor medical
candidates
Those unable to comply
with post-op rehab
Immunosuppressed
Excellent success rate
Pain-free and some
younger patients can
ambulate with assistive
devices
Arthrodesis
Instead of
resection
arthroplasty in
knee
Wichita Nail,
plates, or external
fixator
PROSTALAC for Hips
Allows better patient
mobilization
Control over limb length
discrepancy
Easier second surgery
90-97% success rate
Cultures more likely to be
positive if infection still
present
Longer O.R. time
My Results
28 PROSTALAC’s
 4 cement coated Austin Moore, 24 Depuy
 2 failures for recurrent infection
Both in same patient
 3 failures for dislocation or failure of acetabular
component
7 reimplantations after Girdlestones
 2 late dislocations
 No infections
Knee Antibiotic Cement Spacer
Cement spacer or PROSTALAC
Should have at least 3g vanco powder per 40g
bag of cement
Tobramycin cement not good enough
PROSTALAC in KNEES
Advantages


Able to mobilize with
less scarring
Easier second surgery
Disadvantages


Components do not fit
well
Some studies have
shown longer
persistent drainage
Thank You
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