**5. Management of bone defects**

As osteoarthritis advances, bone defects can distort the natural anatomy of the knee and cause to difficult alignment and implant set.

**Figure 15.** Peripheral medial bone defect on medial tibial plateau. One must avoid over-resection of the medial tibial plateau as it could fracture proximal fibula. Cancellous bone is insufficient to support the tibial implant.

Contained defects occur from a cyst or a cavity and are treated by filling off the defect or bone cut. One must remember that there is a limit for moving the bone cut level. Augmentation with cement, bone, or metal wedges or blocks should be considered in these cases.

**7. Emerging technologies**

needs to be proven.

sally used.

strategies.

**8. Conclusion**

**Author details**

João Bosco Sales Nogueira<sup>1</sup>

Marcelo José Cortez Bezerra3

Patient-specific instruments could be made from preoperative imaging (MRI or CT scans of specific sequences). It could allow the production of manufactured specific cutting guides. These guides are made in respect of the individual anatomy, including osteophytes and bone defects in the correct orientation. It would direct the bone resection before the preplanned knee, avoiding using standard intraoperative cutting guides. Specific guides should require fewer trays of kit, leading to greater operative efficiency, and are expected to reduce operative time and produce more accurate bone cuts. At this point, there are a lot of studies that suggest the use of specific guides with good functional outcomes. Nevertheless, cost-effectiveness still

Robotic surgery combines navigation with a robot that performs the bony resection, controlled by the surgeon. A preoperative CT scan is used to template the knee. It has a theoretical advantage of not deviating from the defined cutting plane or axes of resection. Despite the appeal that it would reproduce better mechanical axis, additional studies are necessary to justify its use outside the experimental environment before it gets univer-

The restoration of adequate mechanical axes is critical for implant survival. Preoperative planning anticipates surgical difficulties and gives a chance for creating resolutive

The ATJ® application for mobile phones has proven useful and comes to optimize the surgical planning in TKAs. As it establishes a rational step-by-step process, based on literature, it

\*, Leonardo Heráclio do Carmo Araújo<sup>2</sup>

2 Hospital Geral de Fortaleza/Santa Casa da Misericórdia de Fortaleza, Fortaleza, Brazil

and

Planning Primary Total Knee Arthroplasties http://dx.doi.org/10.5772/intechopen.72775 19

directs the user to a possible reliable form of surgical planning.

\*Address all correspondence to: bosco.nogueira@centrodojoelho.com.br

3 Universidade de Fortaleza/Santa Casa de Fortaleza, Fortaleza, Brazil

1 Medical School of Federal University of Ceará, Fortaleza, Brazil

Peripheral defects typically occur in varus knees in the posteromedial plateau and in valgus knees in the distal lateral femur. These kinds of defects are also managed with cement, bone graft, and metal augments. When they occur in tibia, the translation of the tibial tray away from the location of the defect could be sufficient. If not deeper than 10 mm, the defect can be eliminated by resecting the tibia at a lower level until, at a maximum of, 20 mm, but these authors recommend using metal augmentation and intramedullary stems to protect the implant from interface shear forces (**Figure 15**).
