Bone and Joint Infections Flashcards
What is arthroplasty?
Putting in an artificial joint
What is resection arthroplasty?
Taking a disease joint out and replacing this with an artificial joint
What is a revision arthroplasty?
Re-operating on an artificial joint
What is arthrodesis?
Fusing two bones together
What is pseudo-arthrosis?
Allowing two bones to articulate against one another but without a joint
Septic arthritis is a medical emergency. T/F?
True
Why should septic arthritis be treated as a medical emergency?
Untreated joint infection can result in loss of cartilage leading to OA in later life and can cause severe sepsis
How does septic arthritis present?
Fever, single hot joint (commonly knee or hip), loss of movement, pain
What investigations should be done in septic arthritis?
Blood cultures, joint aspirate, FBC, CRP, imaging
What pathogens commonly cause septic arthritis?
S.aureus (MSSA, MRSA)
Streptococci (S.pyogenes)
What pathogens are less common causes of septic arthritis?
H.influenzzae Kingella N.meningitidis N.gonorrhoeae E.coli P.auruginosa Salmonella species
What is the minimum length of time that septic arthritis should be treated with IV antibiotics?
2 weeks
What are the risk factors for the development of prosthetic joint infections in primary arthroplasty?
RA Diabetes Obesity Poor nutritional status Concurrent UTI Steroids Malignancy
What are the risk factors for the development of prosthetic joint infections in revision arthroplasty?
Prolonged operating room time
Pre-op infection (teeth, skin, UTI)
Local spread is more common than haematogenous spread for prosthetic joint infections. T/F?
True
Which organisms causing prosthetic joint infections commonly spread locally?
Organisms from the skin surface
When does prosthetic joint infection which has local spread usually manifest?
Immediate post-op period
Why does a prosthesis require fewer bacteria to establish sepsis than in soft tissue?
Avascular surface allows survival of bacteria as it protects bacteria from circulating and immunological defences and most antibiotics
Cement can inhibit phagocytosis and lymphocyte/complement function
What is the presentation of a prosthetic joint infection?
Pain Effusion Warm joint Fever Systemic symptoms Loosening of joint on X-Ray Discharging sinus Mechanical dysfunction
Which antibiotic is given as prophylaxis to prevent prosthetic joint infection?
Cephalosporin
How long before skin incision should cephalosporin be given to prevent prosthetic joint infection?
30-60 minutes
Explain the DAIR method of treating prosthesis infection?
Debride, antibiotics, implant retained
Can be used if prosthesis infection is acute <30 days since insertion, is still mechanical function
Joint washed out to reduce burden of infection, then IV antibiotics started for 4-6 weeks
When would an infected prosthetic joint need to be removed?
If infection occurs >30 days after surgery
What procedures can be used to remove/replace an infected prosthetic joint?
Girdlestone procedure
One stage revision
Two stage revision
Why do the chances of success and cure of infection reduce with each revision surgery to replace am infected prosthetic joint?
Anatomical distortion
Infection becomes harder to suppress
What samples are preferred over a surface swab when trying to culture the causative organism of a prosthetic joint infection?
Tissue
Pus
Fluid
Combination therapies including which antibiotic have the greatest success of treating prosthetic joint infection?
Rifampicin
Antibiotics should be started pre-operatively when treating a patient with prosthetic joint infection. T/F?
False - unless the patient has life-threatening infection
What is osteomyelitis?
Progressive infection of the bone characterised by the death of the bone and the formation fo sequestra
Osteomyelitis can spread via contiguous spread due to…?
Overlyign infection e.g. cellulitis ulcer
Trauma
Surgical inoculation
Acute osteomyelitis is more common in which age group?
Children
Anaerobes can cause osteomyelitis. T/F?
True
How is osteomyelitis treated?
Surgery to debulk the infection back to health bone and manage the dead space that remains with muscle flaps
Infected fractures stabilised
Sinuses derided
IV antibiotics 4-6 weeks
What tissue does diabetic foot infection normally affect?
Bone but can also involve the joints
What is vertebral discitis?
Infected of a disc space and the adjacent vertebral end plates
What are the possible complications of vertebral discitis?
Cord compression
Paraplegia
Disability
What are the possible causes of vertebral discitis?
Septic arthritis
Osteomyelitis
Tuberculosis infection
