Periprosthetic infection involving the joint prosthesis and adjacent tissue

Aetiology

Risk factors

• Presence of comorbidities e.g. rheumatoid arthiritis, diabetes, malignancy
• Use of corticosteriods, TNF inhibitors
• Prior arthroplasty or prior infection at surgical site
• Prolonged duration of surgery
• Postoperative complications
• Staph. aureus bacteraemia (from another cause)

Causative organisms

• Most commonly staph. aureus and staph. epiderdimis
• Cutibacterium acnes - upper limb prostheses
• Rarely strep. sp and enterococcus sp.
• Gram negatives e.g. E. coli, psudomonas aeruginosa
• Very rarely - fungi, mycobacteria sp.

Pathophysiology

Mechanism

• Direct inoculation at time of surgery
• Manipulation of joint at time of surgery
• Seeding of joint at a later time (from bacteraemia)