Revision of infected knee arthroplasties in Denmark

Background and purpose — The surgical treatment of peripros- thetic knee infection is generally either a partial revision proce- dure (open debridement and exchange of the tibial insert) or a 2-stage exchange arthroplasty procedure. We describe the failure rates of these procedures on a nationwide basis. Patients and methods — 105 partial revisions (100 patients) and 215 potential 2-stage revision procedures (205 patients) per- formed due to infection from July 1, 2011 to June 30, 2013 were identifi ed from the Danish Knee Arthroplasty Register (DKR). Failure was defi ned as surgically related death  90 days postop- eratively, re-revision due to infection, or not reaching the second stage for a planned 2-stage procedure within a median follow-up period of 3.2 (2.2–4.2) years. Results — The failure rate of the partial revisions was 43%. 71 of the partial revisions (67%) were revisions of a primary pros- thesis with a re-revision rate due to infection of 34%, as compared to 55% in revisions of a revision prosthesis (p = 0.05). The fail- ure rate of the 2-stage revisions was 30%. Median time interval between stages was 84 (9–597) days. 117 (54%) of the 2-stage revi- sions were revisions of a primary prosthesis with a re-revision rate due to infection of 21%, as compared to 29% in revisions of a previously revised prosthesis (p = 0.1). Overall postoperative mor- tality was 0.6% in high-volume centers (> 30 procedures within 2 years) as opposed to 7% in the remaining centers (p = 0.003). Interpretation — The failure rates of 43% after the partial revi- sion procedures and 30% after the 2-stage revisions in combina- tion with the higher mortality outside high-volume centers call for centralization and reconsideration of surgical strategies.