Zimmer MIS Multi-Reference Surgical Technique

Zimmer MIS Multi-Reference Surgical Technique Manual pdf 35 page image

Zimmer MIS Multi-Reference 4-in-1 Femoral Instrumentation Surgical Technique 33Step EightPerform a Trial ReductionAfter preparing the tibia, select theappropriate Pegged or Stemmed TibialSizing Plate/Provisional that providesthe desired tibial coverage. Check thesize matching chart (for the style ofNexGen Knee implant) for componentmatching instructions.Insert the Femoral Provisional, PatellarProvisional, Tibial Sizing Plate/Provisional, and Articular SurfaceProvisional.Flex and extend the knee with theprovisionals in place. Check the rangeof motion and ligament stability.Perform any necessary soft tissuereleases. With proper soft tissuebalancing complete the tibialcomponent tends to seat itself inthe position where it best articulateswith the femur (Fig. 8a)NOTE: During the trial reduction,observe the relative position of theFemoral Provisional on the tibialArticular Surface Provisional by usingthe lines on both provisionals. Thelines can be used to determine ifposterior rollback is occurring, whetherthe PCL is functional, and if the femoralcomponent will contact the tibialarticular surface in the proper location.If the PCL is properly balanced, theFemoral Provisional should sit nearthe anterior or center lines on thetibial Articular Surface Provisional inextension and near the posterior linein flexion.If the Femoral Provisional sitsposterior to the lines, the PCL may betoo tight or the articular surface maybe too thick. If the Femoral Provisionalsits anterior to the lines, the PCL maybe too loose.After this self-centering process hasoccurred, mark the position of thecomponent with methylene blue orelectrocautery (Fig. 8b). Then removethe provisional components. TheFemoral Extractor can be used toremove the Femoral Provisional.Fig. 8aFig. 8b