Should the tibial stem be moved on the tray?
Researchers who developed scientific exhibit 36 on “Laterally Eccentric Tibial Stem Position in Total Knee Arthroplasty, asked the question, “should the stem be moved 3 mm medial on the tray?” The central stem on a tibial tray in primary and revision total knee arthroplasty gives stability of tray fixation, they said. The stem with extensions will impinge on the lateral cortex of the tibia require greater proximal bone resection if maximal surface coverage by the tray is to be maintained. The researchers concluded from their study that the central tibial stem usually will not cause lateral cortex impingement unless further proximal resection, stem extensions or inadvertent varus position of the tray is required. Since the resected surface is the reference for the stem preparation, the tip of the stem will follow the lateral arc of the medial cortex at each resection level. Placement of the stem 3 mm medial of center will avoid most problems and support the area of the tray where more f
