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An aluminium mold for intraoperative production of antibiotic-loaded PMMA knee prostheses.

Kohl S, Krueger A, Roeder C, Hartel M, Kohlhof H, Schneider C, Eggli S - Acta Orthop (2009)

View Article: PubMed Central - PubMed

Affiliation: Robert Mathys Foundation, Bettlach, Switzerland. sandro.kohl@rms-foundation.com

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For treatment of total knee prosthesis infections, a two-stage protocol with explantation of the infected components, antibiotic cement spacer implantation, and secondary reimplantation of the prosthesis after curing the infection is the accepted standard procedure... The cement spacer is antibiotic-loaded, maintains the articular distance between femur and tibia, stabilizes the knee, and allows passive motion of the knee... Such spacers often show insufficient congruency and have a rough surface, which results in instability and excessive wear... Thus, thick scarring of the joint capsule with limited motion is often found at reimplantation, which requires extensive debridement and arthrolysis... The only commercially available molding system is the StageOne Knee Cement Spacer Molds (Biomet Orthopaedics Inc., Warsaw, IN)... This produces significantly better congruency of the articulating parts, with better stability... The main advantages of this system are the stability of the knee after implantation because of the high congruency of the spacer components, and low friction between the articulating surfaces... Thus, almost no PMMA wear particles can be found at reimplantation of the prosthesis... Stability in combination with a low-friction coefficient permits immediate motion training, which results in a substantially better range of motion at reimplantation of a new implant... Other positive attributes include the possibility of adding high doses of antibiotics and the possibility of correct reconstruction of the joint line and the anatomical axis of the leg... Finally, the reusability of the system is cost-efficient.

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Implantation of the intraoperative molded PMMA knee spacer.
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Figure 0003: Implantation of the intraoperative molded PMMA knee spacer.

Mentions: The 2 molds were produced in a computerized numerical-control sinking machine (DMU 70eV-process) based on the design of the balanSys knee system (size B; D) (Mathys AG, Bettlach, Switzerland). The mold for the femoral spacer consists of 3 parts and for the tibial spacer, of 2. It is made of high-strength aluminium (AA7075 T6 3.4365; density 2.8 kg/dm3 and tensile strength 520–560 Nm/mm2) and coated with Altef. In this process, the surface of the base material is converted into a ceramic coating in which Teflon is integrated. Half of the coating penetrates into the base material, which results in an increase of 25 µm, leading to a standard coating thickness of 50 µm. The mold can be cleaned and sterilized for re-use (Figure 1 and 2).


An aluminium mold for intraoperative production of antibiotic-loaded PMMA knee prostheses.

Kohl S, Krueger A, Roeder C, Hartel M, Kohlhof H, Schneider C, Eggli S - Acta Orthop (2009)

Implantation of the intraoperative molded PMMA knee spacer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823218&req=5

Figure 0003: Implantation of the intraoperative molded PMMA knee spacer.
Mentions: The 2 molds were produced in a computerized numerical-control sinking machine (DMU 70eV-process) based on the design of the balanSys knee system (size B; D) (Mathys AG, Bettlach, Switzerland). The mold for the femoral spacer consists of 3 parts and for the tibial spacer, of 2. It is made of high-strength aluminium (AA7075 T6 3.4365; density 2.8 kg/dm3 and tensile strength 520–560 Nm/mm2) and coated with Altef. In this process, the surface of the base material is converted into a ceramic coating in which Teflon is integrated. Half of the coating penetrates into the base material, which results in an increase of 25 µm, leading to a standard coating thickness of 50 µm. The mold can be cleaned and sterilized for re-use (Figure 1 and 2).

View Article: PubMed Central - PubMed

Affiliation: Robert Mathys Foundation, Bettlach, Switzerland. sandro.kohl@rms-foundation.com

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

For treatment of total knee prosthesis infections, a two-stage protocol with explantation of the infected components, antibiotic cement spacer implantation, and secondary reimplantation of the prosthesis after curing the infection is the accepted standard procedure... The cement spacer is antibiotic-loaded, maintains the articular distance between femur and tibia, stabilizes the knee, and allows passive motion of the knee... Such spacers often show insufficient congruency and have a rough surface, which results in instability and excessive wear... Thus, thick scarring of the joint capsule with limited motion is often found at reimplantation, which requires extensive debridement and arthrolysis... The only commercially available molding system is the StageOne Knee Cement Spacer Molds (Biomet Orthopaedics Inc., Warsaw, IN)... This produces significantly better congruency of the articulating parts, with better stability... The main advantages of this system are the stability of the knee after implantation because of the high congruency of the spacer components, and low friction between the articulating surfaces... Thus, almost no PMMA wear particles can be found at reimplantation of the prosthesis... Stability in combination with a low-friction coefficient permits immediate motion training, which results in a substantially better range of motion at reimplantation of a new implant... Other positive attributes include the possibility of adding high doses of antibiotics and the possibility of correct reconstruction of the joint line and the anatomical axis of the leg... Finally, the reusability of the system is cost-efficient.

Show MeSH