Master Techniques in Orthopedic Surgery Knee CH27

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PART V Alternatives to Total Knee Arthroplasty

Completing Femoral Preparation Use the femoral trimming guide to remove anterior and posterior osteophytes using the drill and lightly tapping posterior with a mallet. Remove posterior osteophytes. Inspect by digital palpation to make sure they have been removed. Sizing the Tibial Component and Trial Insertion The tibial template is placed so that the posterior and medial margins are lined up with the posterior and medial edges of the tibial plateau. Use the tibial hook to ensure that there is adequate placement. Then the guide is pinned into place. The final cut is made in the slot on the tibial template for the keel on the inferior aspect of the tibial component. Inserting the Femoral and Tibial Trials The femoral and tibial trial components are then inserted using the impactor. On the basis of the previous gap balancing, a meniscal bearing of appropriate thickness is inserted. The knee should be ranged through the flexion–extension arc with varus- and valgus-stress testing at 20° of flexion. Cementing Components Before cementing, it is recommended that the femoral and tibial surfaces be roughened by placing multiple small drill holes on the cut surfaces (Figure 27-13). The cementing can be done in either one or two stages, the tibial component first and then the femoral component. The cement is spread on the surface of the tibia in a thin layer and the component is placed (Figures 27-14 and 27-15). The tibial impactor is used to seat the component by impacting from posterior to anterior. The femoral component is cemented next. The femoral trial and feeler gauge are removed. The central hole from the guide is filled with cement and cement is also applied to the inside of the femoral component. The femoral component is tapped in with a mallet (Figure 27-16). Excess cement is removed and the appropriately sized feeler gauge is inserted to provide adequate compression of the tibial component. It is important to keep the knee flexed to 45° and apply an axial load. Excess cement is removed from the edges of the implant. After all the cement has hardened, the joint should be thoroughly irrigated. The final me- niscal bearing is then snapped into place (Figure 27-17). A Davol drain may be placed before closure.

FIGURE 27-14. Cementing of both components is done in separate stages. The tibial component is cemented first using a thin layer of cement on the tibial bone.

FIGURE 27-13. The femoral and tibial surfaces are roughened using multiple small drill holes.

FIGURE 27-15. Tibial component is placed and impacted with the tibial impactor.