BKS® Surgical Technique
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Surgical Technique Balanced Knee® System

Designing Surgeons: Michael H. Bourne, M.D. Salt Lake Orthopedic Clinic Chairman, Division of Orthopedic Surgery, St. Mark’s Hospital E. Marc Mariani, M.D. Salt Lake Orthopedic Clinic President, Salt Lake Orthopedic Clinic The following technique is a general guide for instrumentation of the Balanced Knee® System. It is assumed that the surgeon is already familiar with the fundamentals of total knee replacement. Each patient represents an individual case that may require modification of the technique according to the surgeon’s judgment and experience. Please see the Balanced Knee® System...

Surgical Technique Overview 1. Distal Femoral Resection 4. Proximal Tibial Resection 5. Soft Tissue Balancing and Equalizing Flexion/Extension Gaps 9. Tibial Keel Preparation 3. Anterior and Posterior Resections

Device Description The Balanced Knee® System design is based on proven technology and has over 12 years of successful clinical use. It is offered in a wide range of sizes and options to allow the device to be anatomically specific in a variety of patients. The Balanced Knee® System was designed with the following objectives in mind: • Proven and reproducible clinical results • qualization of the flexion and extension gaps with E soft tissue balancing • Accommodates a wide range of knee deformities • imple and intuitive instrumentation to facilitate S balancing the knee • Easy transition to...

Templates with a 10% magnification are provided by Ortho Development® Corporation for use with preoperative x-rays (Figure 1). Digital Templates are also available through several digital templating software providers. The templates enable the surgeon to estimate the Femoral component and Tibial Tray sizes, and to identify any unusual circumstances specific to the case at hand. The actual component sizes are determined intraoperatively by using the sizing guide and trials. Figure 1: Template overlaid on radiograph

Exposure A host of surgical exposures exists. This technique will illustrate a standard anterior medial parapatellar approach. As cases warrant, alternative approaches such as the trivector, lateral parapatellar, midvastus, subvastus or quad-sparing approaches may be employed. Figure 2: Entering the Medullary Canal Entering the Medullary Canal Use the 8mm I/M Drill to access the medullary canal. The entry point is generally located superior and just medial to the roof of the intercondylar notch (Figure 2). Make certain that the 8mm I/M drill is aligned axially to the femoral canal. I/M...

Distal Femoral Resection Figure 5 shows the Distal Femoral Cut Guide assembly. The assembly includes the Distal Cut Guide (A), the Distal Cut Guide Scaffolding (B), and the Varus/Valgus Alignment Guide (C). Assemble the Distal Cut Guide to the Distal Cut Guide Scaffolding and tighten the locking knob. Insert the assembly into the I/M Alignment Guide and lower it onto the anterior cortex (Figure 6). Adjust the amount of distal femoral resection by rotating the adjustment knob on the Distal Cut Guide Scaffolding (Figure 7). All Balanced Knee Femoral components have a distal condyle thickness...

Femoral Sizing and External Rotation Select the appropriate left or right paddles for the A/P Sizing Guide. Seat and center the Sizing Guide on the prepared distal surface. To avoid notching the anterior cortex, position the Stylus on the anterior cortex of the femur. Compress the Sizing Guide until the stylus contacts the anterior cortex of the femur and the paddles contact at least one of the posterior condyles. Check to ensure that the stylus is not seated on a high spot or an unusually low spot on the anterior cortex, and ensure the A/P Sizing Guide is still flush against the distal...

Anterior and Posterior Resections Select the appropriately sized A/P Cut Guide, as previously determined by the A/P Sizing Guide, and slide it over the Quick Pins (Figure 12) into the holes marked “0” (Figure 12a). The Balanced Knee® System is designed to be anterior referencing. Therefore, the distance from the pinholes on the A/P Cut Guide to the anterior cutting surface is constant from guide to guide, whereas the distance from the pin holes to the posterior cutting surface changes with differing sizes by 4mm (Figure 13). This allows for downsizing of the Femoral component after the...

Proximal Tibial Resection Assemble the 0° Tibial Cut Guide to the proximal end of the Up-Rod and insert the distal end of the Up-Rod into the Tibial Alignment Guide (Figure 16). With the knee in flexion, position the Tibial Alignment Guide assembly by securing the ankle clamp around the distal tibia, just superior to the malleoli. Position the proximal end of the Tibial Alignment Guide on the medial third of the tibial tubercle. The Stylus can be adjusted to indicate the surgeons’ preferred depth of proximal tibia resection. It is recommended to resect 8mm from the prominent side or 2mm...

The extra-medullary alignment guide facilitates a proximal tibia resection that is perpendicular to the longitudinal axis of the tibia and replicates the native posterior slope. Replicate the patient’s native posterior slope by sliding the distal end of the Tibial Alignment Guide anterior or posterior until the cutting slot of the Tibial Cut Guide is parallel to the native slope of the tibial plateau (Figure 17). The distal end of the Tibial Alignment Guide can also be translated in the coronal plane to make the resection perpendicular to the shaft of the tibia and/or correct for...

Patella Preparation Evert the patella and measure its thickness using the Patella Calipers (Figure 20). Determine the amount of patella to resect based on the thickness of the native patella and the thickness of the Patella prosthesis (see Appendix C). Ideally, it is recommended to maintain at least 14-15mm of the patient’s native patella. The depth gage on the side of the Patella Resection Guide indicates the distance from the paddle on the anterior surface of the patella to the resection level. Once the amount of resection has been determined, rotate the dial on the top of the Patella...