FDA Clears Antibiotic-Delivering Spacer for Infected Knee Replacements

Periprosthetic joint infection develops around an artificial joint implant and can be especially difficult to manage after knee replacement. Treatment may require removal of the implant, prolonged infection control, and later reconstruction, while temporary joint support and local antibiotic delivery must be maintained in the interim. A newly cleared device is designed to address these needs by combining antibiotic delivery with load-bearing support.

Mass General Brigham (Boston, MA, USA) researchers have developed a temporary knee spacer that has received 510(k) clearance from the U.S. Food and Drug Administration (FDA). The device is intended for patients who develop infection around an artificial knee implant. After the infected implant is removed, the spacer maintains the joint space and provides structural support until a new artificial joint can be placed.

The spacer incorporates gentamicin into ultra-high-molecular-weight polyethylene, or UHMWPE. This medical-grade plastic is a durable, wear-resistant polymer that is commonly used in artificial joints. By embedding the antibiotic into UHMWPE, the device is designed to release gentamicin directly into the infected joint while preserving the mechanical strength needed to support the patient during treatment.

Infection occurs after approximately 2% of knee replacement surgeries. Standard treatment typically involves multiple operations and placement of a temporary spacer made from antibiotic-loaded bone cement. These cement spacers may provide limited support and may release antibiotics inconsistently, creating a need for more predictable structural and antimicrobial performance.

The technology grew out of research at the Harris Orthopaedics Laboratory. In a 2025 study published in The Journal of Bone & Joint Surgery, investigators reported that very small gentamicin particles produced higher and more sustained antibiotic release. The same approach preserved more than 90% of the polymer’s original mechanical strength.

Mass General Brigham Innovation helped advance the technology from laboratory research toward commercialization. The organization secured patent protection and worked with industry partners with product-development and market expertise. It is also in the process of licensing the intellectual property rights to a large implant manufacturer.

“Our goal was to create a spacer that can deliver antibiotics directly to the affected joint while remaining strong enough to support patients during treatment. This clearance is an important step toward making that technology available for patient care,” said Orhun K. Muratoglu, PhD, director of the Harris Orthopaedics Laboratory and vice chair of clinical innovation in the Department of Orthopedic Surgery at Mass General Brigham.

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