Two-Stage Primary Arthroplasty in the Infected Native Knee: A Systematic Review and Pooled Analysis

The knee is the commonest native joint to develop an infection. A two-stage primary knee replacement, with an interim stage of debridement and cement spacer application, modelled after two-stage revision for periprosthetic joint infections (PJI) has been reported for the management of chronic infections.

To systematically review the literature to find the infection-free survival and outcomes of this operation and explore its indications.

PRISMA guidelines were followed for this review. A systematic search of 4 online databases was conducted on 9/8/2020. After reviewing 226 abstracts and applying our selection criteria, 10 papers were selected for full-text review, and 9 included in the final synthesis.

On pooled analysis, an infection-free survival of 95.6% (CI 94.7-96.4) was found at 2 years in 139 knees, which was unchanged over the remainder of the follow-up (Mean 3.9 years). The complication rate after final implantation was 6% in those that did not develop reinfection. The mean pooled Knee Society Score (KSS) and KSS Function score among 70 patients (4 papers) was 83.4 (80.1-89.0) and 76.8 (71.5-78.0), respectively. The mean range of motion among 82 patients (6 papers) was more than 100°.

Two-stage primary knee replacement is a safe, effective and reliable procedure with good results in the short to medium term. Further studies are required to lay down precise indications and cost-effectiveness of this procedure, in comparison to other strategies for chronic infection. All joint registries should develop methods to identify patients undergoing two-stage procedures, to understand their long-term survival and outcomes.