Articulating spacers in elderly patients affected by periprosthetic knee infection: clinical findings and outcome

Objective: Although the two-stage technique is a validated strategy in periprosthetic joint infections, there is a lack of data on the patients' clinical outcomes after the spacer placement. This study aims at evaluating the quality of life, joint function, and pain in patients over 70 years affected by periprosthetic joint infection treated with a two-stage exchange using metal on polyethylene spacers. Patients and methods: We conducted a follow-up study to evaluate the quality of life and functionality of consecutive patients over 70 years treated for PJI at our institution using a validated assessment set including the Western Ontario and Mac Master University (WOMAC) score, Knee Society Score (KSS), numerical rating scale (NRS). Knee Range of Movement (ROM) before and after the surgery was also analyzed. Results: Forty-five patients with a mean age of 76 ± 5.3 years were included. Coagulase-negative staphylococci were the most isolated microorganisms. In the preoperative study group, the WOMAC score was 48.4 ± 18.9, and the KSS objective and functional scores were 37.6 ± 17.3 and 27.6 ± 22.3, respectively. NRS was 7.3 ± 1.8. After three months of follow-up, we found better results than preoperative clinical evaluation. We retrieved similar results comparing our post-operative PROMS (WOMAC and KSS scores) with published thresholds for treatment success two months after primary total knee arthroplasty. The infection eradication rate was 87%. Conclusions: The two-stage technique confirmed its efficacy in the treatment of PJI. Patients over 70 years who had undergone the first stage of the two-stage technique for PJI showed a good quality of life and knee function.