Detection of locking bolt loosening in the stem-condyle junction of a modular femoral stem in revision total knee arthroplasty.

We report one case of loosening of the locking bolt in the stem-condyle junction of a constrained modular femoral component in revision total knee arthroplasty. Early detection of loosening of the locking bolt was possible using reconstructed view of computerized tomography scans before complete disengagement and radiographic loosening of the stemmed femoral component. When using the Total Condyle III femoral component with a stem extension, surgeons should keep in mind that stress concentration at the stem-condyle junction can result in failure of the locking bolt although it is rare and that loosening or disengagement of the locking bolt may be a sign of a loose stemmed femoral component.