Prosthetic joint infection Flashcards
What is the most serious complication of arthroplasty surgery?
infection!
What should be excluded as a cause of prosthesis failure before reconstructing the failed joint?
infection!
How common is infection after arthroplasty?
rare
1 in 100
What is the trend for the epidemiology of joint infection after arthroplasty?
it is increasing in most types of arthroplasty surgery over the years
What are the commonest group of bacteria that cause joint infection after arthroplasty?
CNS - coagulase negative staph (27%)
What are the types of bacteria that cause joint infection?
G+ cocci are responsible for 7% of infections - the most common of these is CNS
other G+ cocci that cause joint infections are Enterobacter, MRSA, Enterococcus, anaerobes, pseudomonas
the rest of the infections are caused by S. aureus
What is better than treatment of joint infection and why?
prevention is better than treatment!
septic revisions are expensive and protects the pt
What are the methods of prevention of infection after arthroplasty?
laminar flow theatres blood brain barrier disposable gowns and hoods double glove antibiotic loaded cement give the pt a single dose systemic antibiotics - flucloaxacillin and gentamycin
what is done to diagnose a prosthetic joint infection?
history examination XR FBC> ESR, CRP microbiology culture from DEEP ASPIRATION/ DEEP TISSUE samples
what questions may be asked in the history to diagnose joint infection?
was the wound slow to heal after surgery?
recent dental work
what is alpha defensin?
it is an inflammatory marker test like CRP and ESR but it is a cytokine and the test has a higher sensitivity/ specificity
What must be done before a pt has a deep aspiration of their joint?
make sure than have been off antibiotics for at least 2 weeks!
what is the gold standard test for diagnosis of joint infection?
deep aspiration sample which is then sent to microbiology lab to test for organism and sensitivities to antibiotics
What are the aims of treatment of an infected joint?
eradicate sepsis
relieve pain
restore function through rehab
What are the treatment options for prosthesis infection?
Antibiotic suppression Debridement, antibiotics and implant retention (DAIR) Excision arthroplasty One stage exchange arthroplasty Two stage exchange arthroplasty Amputation
When is antibiotics suppression used as a treatment option?
when the pt is unfit for surgery eg elderly and frail
multiple prosthetic joint infections
poor distal skin/soft tissues that are likely to get reinfected eg ulcers
low virulence of the infecting organism so likely to be treated by antibiotics
available oral antibiotics - so pathogen is sensitive
pt tolerates antibiotics
prosthesis is not loose
Will antibiotics suppression eliminate sepsis?
no
What is debridement?
medical removal ofdead, damaged, orinfectedtissueto improve the healing potential of the remaininghealthy tissue
What is a DAIR procedure?
Debridement, Antibiotics and Implant Retention
debride the wound, exchange mobile parts (but not removing the whole prosthesis) and then give antibiotics for 6 weeks
In which cases is a DAIR suitable for?
EARLY post-op infections or ACUTE haematogenous infections
When is a DAIR not suitable?
for chronic infections
if the prosthesis is loose (as it would be better to remove the prosthesis if it was loose)
What is excision arthroplasty?
removal of a prosthesis
Who is offered an excision arthroplasty?
pts who are high risk and frail with multiple co-morbidities
Pts with low functional demand
Uncontrolled with antibiotic suppression
High risk re-infection due to poor skin or soft tissues
What is the disadvantage of doing an excision arthroplasty?
it reduces the functional capacity of the pt as the pt can’t use the limb
What can be done instead of excision arthroplasty if the joint is not to be removed?
arthrodesis - ie fusion of the joint
What is exchange arthroplasty?
change the infected prosthesis for a new clean prosthesis
What does exchange arthroplasty involve?
- Know the organism(s) and their sensitivities
- Debridement of all infected and dead tissue
- Confirmatory intra-operative micro samples
- Appropriate and sufficient antibiotic cover
- Sufficient soft tissue cover/reconstruction
- Sufficient, stable joint reconstruction
What is a one stage exchange arthroplasty?
radical debridement with implantation of a new prosthesis that is cemented with antibiotics and pt is given antibiotics depot - ie locally and systemically, but this happens all in the same operation
What is a two stage exchange arthroplasty?
radical debridement
place in a temporary antibiotic spacer and give systemic antibiotics targeted towards the organism isolated in this first part of the surgery. Antibiotics are given for 6-12 weeks
there is an interval stage between the two operations where there is no ‘joint’ as such and just the antibiotic loaded spacer
then go back 3 months later after the initial infection has been eradicated and put a new prosthesis in which can be cemented with antibiotics +/- bone graft
then the pt is given routine antibiotic prophylaxis as would after any prosthetic limb surgery
