PMC6536804_01
(A) Pre-operative X-ray with knee revision arthroplasty with cemented femoral and tibial stem anchorage without any obvious signs of loosening or osteolysis (A1: ap, A2: lateral). (B) After removal of the revision prosthesis intramedullary rods are placed in the femur and tibia with an antibiotic-loaded PMMA spacer to fill the large dead space as interim knee arthrodesis solution. Cortical windows were needed for complete bone cement removal, which were then fixed with screws. (C) Postoperative ap-view after modular knee arthrodesis with metallic silver coating and connection of the intramedullary femoral and tibial components with a spacer and locking bolts. Intramedullar rods were fixed cementless. (D) 26 months control after modular knee arthrodesis no implant loosening could be evidenced on both ap (D1) and lateral (D2) view.
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F1
The X-ray showed a knee revision arthroplasty with cemented femoral and tibial stem anchorage without any obvious signs of loosening or osteolysis (Fig. 1A). Additionally, a cement spacer was placed in the dead space, which resulted from removal of the knee prosthesis and bone resection (Fig. 1B). Samples taken during this revision also remained sterile and postoperative X-rays showed correct implantation of the knee arthrodesis device (Fig. 1C). X-rays after 26 months showed stable implant conditions (Fig. 1D).
Antibiogram of the infection causative St. epidermidis.
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F2
(A) Metallic silver-coated intramedullary knee arthrodesis system with locking bolts (uncoated) The Metallicsilver coated parts (intramedullary femoral, intramedullary tibial and spacer) appear black. (B) Intraoperative image after implantation of the silver-coated knee arthrodesis system with complete locking of the two spacer parts with 8 locking bolts (4 lateral, 4 medial (not visible)) between the intramedullary femoral component (right) and the intramedullary tibial component (left).
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F3
Femoral and tibial locking intramedullary implants with a diameter of 16 mm for the femur and 14 mm for the millimeters with a length of 200 mm each were selected (Fig. 3A). The femoral and tibial intramedullary components as well as the central spacer connecting the femoral and tibial parts were pre-operatively coated with a 90 nm thick siloxane-microsilver coating (HyProtect , Bio- Gate AG, Nurnberg, Germany) with a relatively low amount of silver (Fig. 3B). Knee arthrodesis surgery was carried out three months after the removal of the prosthesis and the silver coated arthrodesis device was implanted without any problems (Fig. 3B).