Articulating Spacers for Knee Infections

Overseen By Melissa J Shauver, MPH

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Northwestern University

Disqualifiers: Inability to consent, Allergies, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

153 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores two methods for treating infections in artificial knee joints. It compares a one-stage revision, where a new knee with antibiotic cement is placed, to a two-stage revision, which uses an antibiotic-releasing spacer (such as an all-cement articulating spacer or a real-component articulating spacer) before replacing the knee later. The researchers aim to determine which method patients prefer and which provides better long-term function. Individuals with long-term infections in knee replacements might find this trial suitable. As an unphased trial, it offers an opportunity to contribute to research that could enhance treatment options for future patients.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that these articulating spacers are safe for knee infections?

Research has shown that both all-cement and real-component spacers used in treating knee infections are generally well-tolerated. These spacers release antibiotics directly into the knee, helping to control the infection.

Studies have found that all-cement spacers manage infections as effectively as other types. Although they may not last as long as a regular artificial joint, they are safe for temporary use.

Real-component spacers, made from metal or plastic, also effectively control infections. They remain in place until the infection clears or if treatment doesn't work.

Both types of spacers use high-dose antibiotic cement, proven safe and effective for treating knee infections. It is important to note that using these spacers may require another surgery later to replace the temporary spacer with a permanent joint. Overall, these treatments have a strong safety record and are a standard option for knee infections. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the articulating spacers for knee infections because they offer innovative approaches for managing complex joint infections. Unlike traditional static spacers, the all-cement articulating spacer is made using molds and high-dose antibiotic cement, which allows for more personalized fitting and targeted infection treatment with antibiotics like vancomycin and tobramycin. Meanwhile, the durable, real-component articulating spacer uses metal or ceramicized metal with a plastic bearing surface, potentially providing a more durable, long-term solution without the need for immediate revision. Both spacers aim to reduce infection and improve joint functionality, offering new hope for patients with serious knee infections.

What evidence suggests that this trial's treatments could be effective for knee infections?

This trial compares the effectiveness of two types of articulating spacers for treating infections in artificial knees. Participants in one arm will receive an all-cement articulating spacer, made using a mold to form the joint parts. Another arm will involve a durable, real-component articulating spacer, which includes metal or ceramic parts that may function more like a real knee. Research has shown that both types of spacers release antibiotics directly into the knee to combat infections, and using a two-step process with antibiotic spacers successfully controls infections in over 80% of cases. Previous comparisons showed no significant difference in failure rates between these two types of spacers. Both options aim to clear infections and help patients regain knee function, although the choice may depend on personal preferences and other factors. ^{1 2 4 6 7}

Who Is on the Research Team?

Adam I Edelstein, MD

Principal Investigator

Assistant Professor of Orthopaedic Surgery

Are You a Good Fit for This Trial?

This trial is for patients with a chronic infection in their artificial knee joint after initial replacement surgery, who are planning to have the infected joint replaced with an antibiotic spacer. They must meet specific infection criteria and be able to consent. Those with allergies to study materials, soft tissue or bone issues at the site can't participate.

Inclusion Criteria

PJI defined according to Musculoskeletal Infection Society (MSIS) 2018 Consensus Criteria

I have a long-term infection after knee replacement and need surgery to place an antibiotic device.

Exclusion Criteria

I am unable to give consent by myself.

Allergies to study materials (cement, vancomycin, tobramycin)

I have an infection at my knee replacement site.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Surgery and Initial Treatment

Surgery to remove the artificial knee and place an antibiotic spacer or new artificial knee with antibiotic cement, followed by 6 weeks of IV antibiotics

6 weeks

1 visit (in-person) for surgery, followed by regular monitoring

Postoperative Monitoring

Participants are monitored for complications and recovery progress, with questionnaires administered at 6 weeks, 6 months, 12 months, and 24 months

24 months

Multiple visits (in-person and virtual) at specified intervals

Follow-up

Participants are monitored for long-term outcomes, including pain, function, and satisfaction

5 years

What Are the Treatments Tested in This Trial?

Interventions

• All-cement articulating spacer
• Real-component articulating spacer

Trial Overview The study compares two treatments for infected knee replacements: one-stage revision using a special cement that releases antibiotics, allowing near-normal activity but may need future replacement; versus two-stage revision which uses a temporary spacer then later surgery for durable joint placement.

How Is the Trial Designed?

Group I: Observation Experimental Treatment 3 Interventions

Patients who do not wish to be randomized or who meet the randomization-specific exclusion criteria will be offered enrolment into the non-randomized, prospective observational arm of the study. The participant and their surgeon will collaboratively decide which of the 2 treatments the participant will receive.

Group II: All-cement articulating spacer Active Control 1 Intervention

An articulating spacer with a tibial and femoral component made of cement using molds, that are cemented in place; use of highdose antibiotic cement (at least 2g/batch, including vancomycin and tobramycin); use of dowels at discretion of surgeon; 6 weeks IV antibiotics; intent to reimplant definitive prosthesis if infection eradicated.

Group III: Durable, real-component articulating spacer Active Control 1 Intervention

Uses metal (or ceramicized metal) on plastic for bearing surface; use of high-dose antibiotic cement (at least 2g/batch, including vancomycin and tobramycin); no cones/sleeves, no pressurized cement in canal; use of stems/dowels/augments and level of constraint at discretion of surgeon; 6 weeks IV antibiotics; intent to leave in situ indefinitely/until clinical failure.

All-cement articulating spacer is already approved in United States, European Union for the following indications:

Approved in United States as Antibiotic spacer for:

• Periprosthetic knee infection

Approved in European Union as Articulating antibiotic spacer for:

• Chronic periprosthetic knee infection
• Infected total knee arthroplasty

Who Is Running the Clinical Trial?

Northwestern University

Lead Sponsor

Trials

1,674

Recruited

989,000+

Published Research Related to This Trial

Articulating antibiotic spacers used during two-stage exchange arthroplasty for infected total knee and hip replacements have an infection eradication rate of about 90%, making them highly effective.

These spacers also lead to better outcomes, including a higher range of motion after reimplantation and lower complication rates compared to nonarticulating spacers, indicating their safety and efficacy in appropriate patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Point/Counterpoint: Nonarticulating vs Articulating Spacers for Resection Arthroplasty of the Knee or Hip. Wyles, CC., Abdel, MP.[2021]

Articulating cement spacers can be safely maintained for up to 7 years in patients with severe knee conditions, providing pain relief and improved function without major complications or signs of recurrent infection during that time.

However, the case highlights the risk of progressive bone loss and the potential for mechanical issues, such as fractures, necessitating careful monitoring and consideration for future surgeries like total knee arthroplasty.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Antibiotic-impregnated articulating cement spacer maintained for 7 years in situ for two-stage primary total knee arthroplasty: a case report. Park, YB., Ha, CW., Jang, JW., et al.[2020]

A new method for creating intraoperatively-made cement-on-cement antibiotic-loaded articulating spacers for infected total knee arthroplasty was developed, allowing for customization in size and antibiotic delivery without increasing surgical time.

In a study of 17 patients treated between 2004 and 2007, this method showed potential benefits in improving knee mobility and function during the recovery period, although one patient required amputation due to persistent infection.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intraoperatively-made cement-on-cement antibiotic-loaded articulating spacer for infected total knee arthroplasty. Shen, H., Zhang, X., Jiang, Y., et al.[2016]

In a study of 141 patients with prosthetic knee infections, posterior-stabilized (PS) spacers showed a significantly lower rate of mechanical complications (9.3%) compared to cruciate-retaining (CR) spacers (45.5%), indicating better safety for PS spacers.

PS spacers also resulted in better functional outcomes, with higher Hospital of Special Surgery (HSS) knee scores (72.3 vs. 63.8) and greater range of motion (90.3° vs. 80.6°) compared to CR spacers, while both types effectively controlled infection.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cruciate-Retaining vs Posterior-Stabilized Antibiotic Cement Articulating Spacers for Two-Stage Revision of Prosthetic Knee Infection: A Retrospective Cohort Study. Lin, TL., Tsai, CH., Fong, YC., et al.[2021]

The use of self-made, antibiotic-loaded cement articulating spacers in 22 patients with infected total knee arthroplasty resulted in a 100% infection control rate after implantation, with no recurrence of infection during an average follow-up of 29.8 months.

Patients showed significant improvement in knee function, with the HSS score increasing from an average of 40.5 to 88.7 after treatment, and a high satisfaction rate of 95.3%, indicating the effectiveness and reliability of this approach.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Treatment of infected total knee arthroplasty with a self-made, antibiotic-loaded cement articulating spacer]. Zhang, Q., Zhou, YG., Chen, JY., et al.[2013]

In a study of two-stage revision total knee arthroplasty using antibiotic-impregnated articulating spacers, over 95% of cases achieved successful infection control while maintaining good functional outcomes.

However, the presence of methicillin-resistant organisms was associated with higher failure rates, indicating a need for careful management of infections caused by these resistant bacteria.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Articulating antibiotic impregnated spacers in two-stage revision of infected total knee arthroplasty. Munro, JT., Garbuz, DS., Masri, BA., et al.[2012]

Antibiotic-loaded cement spacers are highly effective in managing periprosthetic hip and knee joint infections, achieving infection control rates over 90% with two-stage exchange arthroplasty.

The review highlights important factors such as the indications for using spacers, their production methods, and the pharmacokinetics of the antibiotics used, which are crucial for ensuring clinical success and minimizing complications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Therapeutic Use of Antibiotic-loaded Bone Cement in the Treatment of Hip and Knee Joint Infections. Anagnostakos, K.[2022]

A two-stage total knee arthroplasty (TKA) using a colistin-loaded antibiotic-impregnated cement spacer effectively managed a vancomycin-resistant Pseudomonas aeruginosa infection in a 71-year-old patient, demonstrating its efficacy in treating complex joint infections.

The local delivery of colistin via the cement spacer minimized systemic side effects, allowing for effective infection control without causing acute kidney injury, which is a common risk with systemic colistin administration.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Two-stage approach to total knee arthroplasty using colistin-loaded articulating cement spacer for vancomycin-resistant Pseudomonas aeruginosa infection in an arthritic knee. Chang, MJ., Song, MK., Shin, JH., et al.[2020]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8959870/

All-Cement Spacers vs Sterilized Replanted Metal ... This study compared the outcomes of all-cement articulating spacers and sterilized replanted metal-polyethylene articulating spacers for PJI following TKA.

2. arthroplastyjournal.org arthroplastyjournal.org/article/S0883-5403(21)00079-6/abstract

All-Cement vs Real-Component Spacers Few studies have compared different articulating spacer constructs. This study compares the outcomes of real-component and all-cement ...

3. clinicaltrials.gov clinicaltrials.gov/study/NCT06293352

Real-component Vs All-cement Articulating Spacers for ... The new artificial joint with antibiotic cement will function almost the same as the original artificial knee. This means that while the infection is healing ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12311390/

No difference in failure between static, articulating, and ... Comparing the Efficacy of Articulating Spacers in Two-Stage Revision for Periprosthetic Joint Infection Following Total Knee Arthroplasty ...

5. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0968016017301400

Success rates, characteristics, and costs of articulating ... Two-stage revision knee arthroplasty with antibiotic cement spacers has historically provided infection control rates above 80% [8], [13], [14], [15]. Although ...

6. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0968016025002054

Real-implant articulating spacers for chronic knee ... Real-implant articulating spacers for chronic knee prosthetic joint infection have similar infection control rates as all-cement spacer ...

7. arthroplasty.biomedcentral.com arthroplasty.biomedcentral.com/articles/10.1186/s42836-023-00167-6

Articulating spacers: what are available and how to utilize ... This study aimed to review the key concepts, types, and outcome evaluations of articulating spacers in the two-stage exchange for PJI.