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Cement Technique
“There is no excuse for poor cement technique!” This quote was heard quite often from Dr. Krackow, and in every case he paid close attention to detail during this step of the total knee arthroscopy (TKA) procedure. Much has changed since the first edition of this textbook, but the polymethylmethacrylate (PMMA) that is used today is the essentially the same as that used in the early 1990s. Many more surgeons are now using a higher viscosity cement, but the one addition that has changed is the more frequent use of antibiotics in the cement. The advantages of adding antibiotics are not a topic for this chapter, and most agree that its use in higher-risk individuals is most likely beneficial. There has also been a surge in the use of cementless fixation in primary TKA, but to date registry information continues to show good long-term survivorship for cemented primary TKA.
Cement can be classified according to viscosity. Low-, medium-, and high-viscosity cements are available from a number of manufacturers. The type of cement surgeons use is greatly influenced by their training and what they have been used to over their residency and fellowship. Dr. Krackow’s preference was always a low-viscosity cement. For operating room (OR) efficiency, many surgeons have switched to higher viscosity options because of a shorter time to a “working phase.” No matter the choice, surgeons must be familiar with the manufacturer’s recommendations for mixing, the working window recommendations, and the need to have a team approach in which everyone in the OR understands the importance of each step of the cementation procedure. An adequate number of assistants to ensure retractors are held in place and an OR technician who has been adequately trained in the manufacturer’s procedures to optimally mix and prepare the cement are essential.
Step 1: Exposure
Proper exposure and retractor placement are essential so that all surfaces to be cemented can be properly prepared. We prefer to have the knee hyperflexed with medial and lateral soft-tissue sleeve retractors and the patella everted. The addition of a posterior cruciate ligament (PCL) type retractor to sublux the tibia forward also is recommended. Adequate exposure of the tibia to allow seating of the baseplate without interference from the femoral surfaces should be ensured ( Fig. 11.1 ).
Step 2: Bone Surface Preparation
Any areas on the tibia or distal femur (especially the lateral condyle of a valgus deformed knee) that are sclerotic should be drilled to ensure mechanical penetration into the area for fixation. We find a 2-mm drill bit to be sufficient for this step. Pulse lavage of the tibia/femur and patellar surfaces is then carried out to the point that no “blush” of blood or remnant of fatty fluid from the intramedullary contents is evident. A thorough drying of the surfaces and the keel preparation of the tibia are then carried out, and dry sponges are placed to keep these surfaces dry until ready for cementation (see Fig. 11.1 ). Adding a small-tip suction to a tibial bone block pin site can aid in keeping any marrow contents from rising to the surface during this drying time. If an intramedullary rod was used for femoral instrumentation, a bone block of the canal also can help keep surfaces dry. Dr. Krackow routinely used thrombin- or epinephrine-soaked sponges on the cancellous bone to enhance drying of the marrow contents.
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