Image Quiz
An Unanticipated Postoperative Radiograph1
A seventy-two-year-old man underwent revision total knee arthroplasty, performed because of infection, sixteen weeks following the primary total knee replacement. A Coordinate revision knee system (DePuy, Warsaw, Indiana) was used to revise both the femoral and tibial component. We used a tibial tray with a 100-mm modular intramedullary stem extension. At surgery, both components were clean and dry, and the assembly was constructed and impacted on the back table. Our technique included inspection of both the shank and the female component for contamination, cleaning of the shank with gauze, and assembly of the two components by hand followed by impaction of the stem by two blows with a mallet. The tibial tray construct was placed on the back table and was protected with gauze prior to impaction. The final construct was then inspected and tested manually for a secure fit by the surgeon. Following preparation of the tibial metaphysis, polymethylmethacrylate was packed into the exposed cancellous bone and was applied to the undersurface of the tibial tray. No cement was applied to the intramedullary stem, and the Morse-taper junction was free of cement. The tibial component was inserted in anatomical alignment initially by hand and then with two hammer blows to the tibial impactor device; the component was held manually in situ until the cement had cured. Excessive force was not required to seat the component, and a circumferential, 1-mm thick mantle was achieved between the prosthesis and the bone. A routine postoperative radiograph was made.
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