[Infected knee prostheses. Part 2: chronic late infections].

Objective: Treatment of late and chronic infections, which require the replacement of all the infected implant material.

Indications: All infections lasting more than 4 weeks that have been proven to be bacterial and/or obvious signs of infection.

Contraindications: Unsuitable for anesthesia, high acute infection with sepsis and risk for bacteremia with danger to life, large soft tissue damage where plastic surgery coverage is not possible.

Surgical Technique: Arthrotomy, synovectomy, removal of all foreign bodies including all residue of polymethylmethacrylate (PMMA), jet lavage, spacer, drainage, wound closure or temporary closure using vacuum sealing.

Postoperative Management: Bed rest with a leg brace and drainage until daily drainage volume is <50 ml, then mobilization with no weight-bearing in an orthesis, 4 weeks systemic antibiotics, after 2 weeks without antibiotics aspiration of the joint, when no bacteria are found reimplantation of a revision TKA (total knee arthroplasty) and with plastic surgery for coverage (gastrognemius flap) if necessary, when bacteria are found again revision with exchange of the spacer.

Results: In the literature, the success rate for both the one-stage or the two-stage procedure is about 80-95%. In our very nonhomogeneous collective the overall rate of success is about 81%.