PMC3789291_01
Radiographs of the left knee immediately after the patient sprained his knee and became unable to walk. An anteroposterior radiograph shows a radiolucency 1 mm in depth beneath the lateral aspect of the tibial component ((a), arrow), and the lateral view indicates a condylar fracture ((b), arrow).
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fig1
An anteroposterior radiograph showed a radiolucency 1 mm in depth beneath the lateral aspect of the tibial component (Figure 1(a), arrow), and the lateral view indicated a condylar fracture (Figure 1(b), arrow).
Stress radiographs of the left knee before the primary total knee arthroplasty (TKA) ((a) varus stress, (b) neutral, and (c) valgus stress). Severe joint destruction and instability are seen, indicating neuropathic arthropathy.
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fig2
Stress radiographs for the left knee taken before the primary TKA showed severe joint destruction and instability (Figures 2(a)-2(c)), strongly suggesting neuropathic arthropathy.
Radiographs of the left knee three months after the patient became unable to walk. Intra-articular bony fragments are enlarged and form giant ectopic ossified masses ((a), (b), arrows). Note that the femoral component is displaced and shifted posteriorly (b).
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fig3
As a result, the intra-articular bony fragments grew larger to form giant, ectopic ossified masses (Figures 3(a) and 3(b), arrows).
(a) Intra-articular giant ossified masses (12 x 4 and 8 x 4 cm in size) were firmly adherent to the posterior and medial capsules and required special care to extirpate. (b) Hematoxylin-eosin staining of the ossified mass showing typical structures of mature spongiosa.
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fig4
Two large ossified masses (12 x 4 and 8 x 4 cm in size, Figure 4(a)) were firmly adhered to the posterior and medial capsules but were successfully and completely extirpated. Hematoxylin-eosin staining of the ossified masses showed typical structures of mature spongiosa (Figure 4(b)).