A novel polyethylene-based knee spacer (United Cellbrick Knee Spacer), for the purpose of infection control, was developed to enhance biomechanical safety and surgical convenience of articulating knee spacers. In the present study, Articulating Spacers were compared to the United Cellbrick Knee Spacers in a practical setting to enhance our understanding of the safety and performance of United Cellbrick Knee Spacer.

Two-stage exchange arthroplasty, which involves the removal of infected prostheses and introduction of a temporary antibiotic-loaded cement spacers at the infection site, has been widely accepted among treatment options. Antibiotic-loaded cement spacers facilitate in maintaining joint space, limb length, soft tissue tension, and lengthening the period of effective antibiotic release until infection control has been accomplished.

Although articulating knee spacers have demonstrated advantages in joint mobility and clinically successful rates in infection control, issues relating to biomechanical safety contributed by cement material characteristics have been noted. Surgeons had to implement alternative methods for the construction of an intramedullary spacer to provide sufficient infection control for deeper infection sites which could cause surgical inconveniences. A novel polyethylene-based knee spacer, for the purpose of infection control, was developed to enhance biomechanical safety and surgical convenience of articulating knee spacers.

The investigators aim to conduct a clinical study comparing the use of Articulating Spacers to United Cellbrick Knee Spacers in a practical setting to better understand the safety and performance of United Cellbrick Knee Spacers and to enhance the clinical confidence of investigators. A total of 10 participants who are undergoing two-stage exchange arthroplasty at Linkou Changgung Memorial Hospital will be recruited, including 5 participants in the "Spacer" group and 5 participants in the "Novel Spacer" group.

Participants in the "Spacer" group will receive a full-cement spacer (Stryker, Simplex P) made of broad-acting antibiotics (Vancomycin and Gentamicin) produced in the hospital.

Participants in the "Novel Spacer" group will receive a United Cellbrick Knee Spacer, where the femoral and tibial spacers will be filled with bone cement (Stryker Simplex P) with antibiotics (Vancomycin and Gentamicin).

Spacer survivorship defined as no removal or revision of any components as a result of mechanical failure or complications will be analyzed. Blood tests, joint effusions, and x-ray inspections will also be collected for analysis.

Inclusion Criteria

Patients who are 18 years of age or older, suitable for temporary knee joint implants, and will be undergoing treatment in Linkou Chang Gung Memorial Hospital who meet the following criteria and have skeletally mature bones:

1. Patients who are diagnosed with infection before surgery and are expected to undergo two-stage procedure for total knee replacement (TKR);
2. Patients who are willing to use traditional mobility aids (such as crutches, walkers) during implantation;
3. The implantation time of the temporary knee implant shall not exceed 180 days.

Exclusion Criteria

1. Patients who are allergic to or have suffered from allergies to any component of the implant, the bone cement used together or antibiotics.
2. Patients who cannot perform two-stage knee replacement surgery due to decreased immune response or other relevant clinical conditions.
3. Patients who have not previously received total knee replacement surgery, and the secondary infection is caused by trauma, septic arthritis or other surgery.
4. Sufficient support and / or fixation for implants due to disease, soft tissue defects, bone defects or other relevant clinical conditions.
5. Inability or unwillingness to return to hospital for evaluation.
6. Cognitive function impairment makes the subject unable to answer questions or cooperate with instructions.
7. Other systemic comorbidities lead to severe impairment of the subject's mobility and function.