16:12
Published February 01, 2014

Balancing A Total Knee Arthroplasty With A Navigation System

Navigation systems have been proven as very accurate measurement tools, and such systems may help surgeons achieve a more accurate and reproducible soft-tissue balance during total knee arthroplasty (TKA). The registration process involves a kinematic analysis of hip, knee, and ankle joints. The navigated technique is a tibia-first procedure. After the tibia osteotomy, the gaps are measured at 0° and 90° of knee flexion with a laminar spreader with independent medial and lateral openings. After completion of the gap measurement, the system displays a summary of all registered data that will allow the virtual planning of the balancing steps and of the femoral resections.A surgeon may decide to first use a balancing technique with extension gap balancing, a balancing technique with flexion gap balancing, or a measured resection technique. He or she may virtually changethe height and orientation of the distal and posterior femoral resection, the anteroposterior positioning of the femoral implant, or the height of the tibia implant and choose to perform any necessary release. All simulations can be repeated and modified according to the surgeon's philosophy and compared before performing any femoral resection.When the planning is completed and the surgeon feels comfortable with its result, the femoral resection may be performed under navigation control. The final implant may be inserted, and the navigation system allows for controlling the expected specification. With the help of a navigation system, and especially with the help of virtual planning, appropriate ligament balance can be obtained for virtually all cases of TKA. This leads to more questions: Should the same routine planning process be used for any patient? Or should the surgeon perform tailored planning for each individual case? There is currently no scientifically supported answer to these questions, but this topic might be a matter of future concern.