case_images: PMC6536801_01
case_images: 7/30/2013. AP (A) and Lateral (B) radiographs at the time of initial consultation demonstrating a stemmed TKA with substantial effusion and patella alta.
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case_images: F1
case_images: After persistence of PJI was suspected, she was referred to a musculoskeletal infection specialist for consultation (Figure 1).
case_images: 9/30/2013. Postoperative AP (A) and Lateral (B) radiographs demonstrating appropriate alignment of the knee after explantation of components and PMMA antibiotic spacer insertion.
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case_images: F2
case_images: The patient underwent explantation of her TKA and insertion of a PMMA antibiotic spacer impregnated with vancomycin and tobramycin on 9/28/2013 (Figure 2).
case_images: 8/5/2014. AP (A) and Lateral (B) radiographs demonstrating substantial effusion of the knee joint, and lucency and periprosthetic loosening around the stemmed tibial implant.
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case_images: F3
case_images: At a 6 month postoperative visit on 8/5/2014 the patient reported "popping" of her knee and radiographs demonstrated loosening around the tibial component (Figure 3).
case_images: 1/20/2015. AP (A) and Lateral (B) radiographs demonstrating a locked lower extremity arthrodesis nail through a static antibiotic cement block.
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case_images: F4
case_images: Due to persistence of her infection now after two 2-stage revisions, it was recommended at this time that the patient undergo component explantation with a knee arthrodesis and an extended course of IV clindamycin and ciprofloxacin (Figure 4).
case_images: 1/8/2018. AP (A) and lateral (B) radiographs demonstrating progressive lysis of the proximal tibia below the PMMA antibiotic cement spacer.
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case_images: F5
case_images: Plain radiographs demonstrated progressive lytic changes of the tibia suggestive of abscess formation and osteomyelitis (Figure 5).
case_images: Intraoperative appearance of wound demonstrating diffuse nodular involvement of the joint.
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case_images: F6
case_images: Upon exposure, the tissue bed around the proximal tibia and distal femur was observed to have an unusual, pebble-like appearance (Figure 6).
case_images: Hematoxylin and eosin histopathology at Low (100x) (A) and High (200x) (B) power imaging demonstrating squamous cell carcinoma, with nests of epithelioid cells and distinguishing keratinous debris
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case_images: F7
case_images: Intraoperative frozen section pathology consultation was obtained, returning a diagnosis of squamous cell carcinoma (Figure 7).