PMC6334334_01
(a) Clinical photograph of the left knee showing the prepatellar swelling and the discharging sinus. (b) A syringe showing the colour of the aspirated fluid.
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fig1
The punctum was draining a yellowish discharge on pressure (Figure 1(a)). Needle aspiration of the prepatellar bursa yielded 50 mL of slightly turbid straw-coloured yellowish fluid that was sent as per our protocol for cell count determination, microcrystal analysis, Gram staining, and Ziehl-Neelsen (ZN) staining for acid-fast bacilli (Figure 1(b)).
(a) Plain lateral view radiograph of the left knee showing the prepatellar soft tissue swelling and otherwise well-fixed prosthesis with no signs of osteolysis at the bone-prosthesis interface or at the patella. (b) Plain lateral view radiograph of the same knee at the 6-year follow-up showing regression of the swelling and otherwise normal appearance of the prosthetic knee and the patella.
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fig2
Plain radiographs of the knee showed a prepatellar soft tissue swelling (Figure 2(a)). At the most recent 6-year follow-up, he was doing well with no evidence of local recurrence or prosthetic loosening (Figure 2(b)).