Trends in the treatment of infected knee arthroplasty

Essential treatment methods for infected knee arthroplasty involve DAIR (debridement, antibiotics, and implant retention), and one and two-stage exchange arthroplasty.

Aggressive debridement with the removal of all avascular tissues and foreign materials that contain biofilm is mandatory for all surgical treatment modalities.

DAIR is a viable option with an acceptable success rate and can be used as a first surgical procedure for patients who have a well-fixed, functioning prosthesis without a sinus tract for acute-early or late-hematogenous acute infections with no more than four weeks (most favourable being < seven days) of symptoms. Surgeons must focus on the isolation of the causative organism with sensitivities to bactericidal treatment as using one-stage exchange.

One-stage exchange is indicated when the patients have:

1. minimal bone loss/soft tissue defect allowing primary wound closure,

2. easy to treat micro-organisms,

3. absence of systemic sepsis and

4. absence of extensive comorbidities.

There are no validated serum or synovial biomarkers to determine optimal timing of re-implantation for two-stage exchange.

Antibiotic-free waiting intervals and joint aspiration before the second stage are no longer recommended. The decision to perform aspiration should be made based on the index of suspicion for persistent infection.

Re-implantation can be performed when the treating medical team feels that the clinical signs of infection are under control and serological tests are trending downwards.