Synicem Hip Spacer; Synicem Knee Spacer; Synicem Shoulder Spacer

The Synicem Hip, Knee, and Shoulder Spacers are temporary antibiotic-impregnated bone cement implants used during two-stage revision arthroplasty procedures to treat joint infections. Each spacer maintains joint space and limb length while delivering gentamicin antibiotics systemically; they are implanted after removing infected prostheses and removed after infection clearance to allow permanent prosthesis implantation, with a maximum implantation duration of 6 months.

The Synicem Spacers are gentamicin-impregnated polymethylmethacrylate (PMMA) bone cement with stainless steel cores. Hip spacers have femoral head sizes of 40–56 mm and stems of 120–250 mm; knee spacers feature tibial and femoral components with specified dimensions; shoulder spacers have head sizes of 40–48 mm and stems of 120 mm. All three are supplied sterile as single-use devices.

Testing followed ISO 10993 standards for biocompatibility evaluation including cytotoxicity (ISO 10993-5), sensitization (ISO 10993-10), irritation (ISO 10993-23), acute systemic toxicity (ISO 10993-11), material-mediated pyrogenicity (ISO 10993-11), and genotoxicity (ISO 10993-3). Mechanical testing included femoral stem and neck fatigue, wear testing for hip spacers, fatigue and wear for knee spacers, and static and dynamic fatigue for shoulder spacers. MRI safety testing was also conducted per FDA guidance.

The Synicem Spacers demonstrate substantial equivalence because they have identical indications for use and comparable design features to the predicate devices (Spacer-G, Spacer-K, and Spacer-S); bench testing showed equivalent performance characteristics in mechanical properties and antibiotic elution kinetics; biocompatibility and toxicological testing confirmed the materials are safe; and any minor differences in design and size do not raise new safety or effectiveness questions, as confirmed by performance and mechanical testing equivalence to predicate spacers.