Disassembly of threaded junction between stem extension and femoral component in a total stabilizer revision total knee arthroplasty.

We report an unusual case of disassembly of threaded junction between stem extension and femoral component in a 6-year-old total stabilizer revision total knee arthroplasty. Aseptic loosening of femur component will tend to cause increased stresses at the stem-condylar junction of a modular femoral prosthesis, especially if femur component is flexed. The modular junction may therefore be unable to withstand the concentrated force and lead to disassembly.