PMC6536801_01
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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F1
After persistence of PJI was suspected, she was referred to a musculoskeletal infection specialist for consultation (Figure 1).
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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F2
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).
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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F3
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).
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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F4
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).
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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F5
Plain radiographs demonstrated progressive lytic changes of the tibia suggestive of abscess formation and osteomyelitis (Figure 5).
Intraoperative appearance of wound demonstrating diffuse nodular involvement of the joint.
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F6
Upon exposure, the tissue bed around the proximal tibia and distal femur was observed to have an unusual, pebble-like appearance (Figure 6).
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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F7
Intraoperative frozen section pathology consultation was obtained, returning a diagnosis of squamous cell carcinoma (Figure 7).