A STANDARDISED TWO-STAGED REVISION PROTOCOL FOR THE MANAGEMENT OF INFECTED TOTAL KNEE ARTHROPLASTY. MID-TERM (2–6 YEARS) OUTCOME STUDY.

Abstract

Two-staged revision TKA is a common strategy for the management of infected TKA (i-TKA) in properly selected patients. However, there is considerable variation in the parameters (e.g. the duration of intravenous administration of antibiotics and of the time interval between the stages, the intraoperative use of frozen sections, the use of knee aspiration etc.) of the treatment protocol among Orthopaedic Centres making the comparative evaluation of results difficult. The aim of this study is to present a standardised two-staged revision protocol with satisfactory mid-term clinical outcome.

Thirty-four consecutive cases of infected primary TKAs were treated in our department between 2000 and 2006. For 24 of them the postoperative follow-up is greater than 2 years. All patients underwent the same treatment protocol: knee aspiration prior to implant removal and surgical debridement, more than 5 specimens for frozen sections and cultures (aerobic, anaerobic and fungi) during the first stage, custom antibiodic impregnated cement spacers, intravenous administration of antibiotics for 3 weeks followed by 3 weeks of per os administration based on culture and antibiogram, a 6-week interval free from antibiotics, second aspiration and second stage with repetition of frozen sections and cultures. In the case of positive frozen section specimens during the second stage the implantation of a new prosthesis was cancelled and a different management strategy was introduced. Preoperative and postoperative data were collected in the form of Total Knee Society Score (knee score and functional score), Oxford-12 Score, laboratory parameters and radiographs at regular intervals.

At the final follow-up 22 out of 24 patients were free of infection. In four patients (2 Host C and 1 Host B) the 2nd stage was repeated (2–6 times) due to polymicrobial infection and positive intraoperative frozen sections. In one of them a knee arthrodesis was finally performed. The diagnostic accuracy of knee aspiration before the 1st stage was low. Total Knee Society Score rose from a preoperative average of 64 (50 to 95) to a postoperative average of 145 (130 to 180). The Oxford 12 score also rose from a preoperative average of 52 (44 to 58) to a postoperative average of 30 (23 to 38). At the final follow-up no radiological signs of implant loosening were observed.

The above standardised protocol of two-staged revision in i-TKA, when indicated, can provide satisfactory mid-term clinical results.