**2.2. Digital planning using ATJ® mobile phone application**

Despite the fact that manual planning is an affordable method, it lacks portability. The surgeon must have manual tools such as a pencil; an eraser; a protractor; and rulers, big enough to measure the whole LLR film. Besides, the surgeon needs to make mathematical conversions and must comprehend a rational methodology of planning on TKA.

textbooks anywhere, anytime, and the provision of resources for the development of innovative teaching methods [9]. By facilitating real-world integration, mobile learning aided by mobile computing (Mobile Learning or m-learning) has created opportunities for develop-

**Figure 2.** Manual templating. First, the anatomical and mechanical axis of the femur and tibia are defined. MAFÂ is measured by using a protractor. A perpendicular cut is measured from MAF and MAT. To correctly place the bone cut lines, the surgeon must mathematically convert printed LLR film size to real size. To do it, the surgeon needs manual

Planning Primary Total Knee Arthroplasties http://dx.doi.org/10.5772/intechopen.72775 5

An interdisciplinary team, involving health and computer science areas, developed an application (ATJ®) that is capable of conducting the surgeon though a step-by-step process (same described

ment of new teaching strategies in different areas [10].

tools such as pencil, eraser, rulers, protector, and goniometer.

Considering the current computational resources used as tools to support medical practices, the paradigm known as *mHealth*, which consists of the use of mobile computing resources in health, stands out. When applied to favor teaching and learning processes, mobile technologies provide numerous benefits, such as increased resources for student learning, access to


perpendicular cut to the MAF, by positioning the distal femoral cut guide in a valgus angle to

After knowing the inclination of the distal femoral cut, the surgeon should evaluate the level of bone resection, anticipating the amount of bone resection. Usually, in a primary TKA, the level of bone resection corresponds to the femoral component thickness (e.g*.,* 9 mm). This step simulates the surgical moment when the surgeon places the distal femoral cut guide onto the distal femoral bone. Using a protractor, the surgeon draws a line perpendicular to the MAF above the first point of the distal femoral bone contact (e.g., 9 mm), from distal to proximal. By doing it, the surgeon could simulate the level and inclination of the distal femoral cut. One should notice that the LLR film does not correspond to real size, being reduced to fit on the film frame. Typically, the amount of reduction in size is reported on the printed film and

The same rationality is applied to the tibial bone. The mechanical and anatomical axes are coincident on the tibia, so the mechanical axis of the tibia (MAT) can be defined as a line drawn from the center of the tibial spines to the center of the talus. Mechanical and anatomical axes are usually coincident on the tibia. The mechanical axis of the tibia (MAT) can be defined as a line drawn from the center of the tibial spines to the center of the talus. After defining MAT, tibial cut is planned perpendicular to the MAT. Usually, surgeons plan to cut 8–10 mm below the unworn side of the tibial plateau, but it can be adjusted to best fit the components and balance the knee. So, the surgeon places a line from proximal to distal, at the level desired below the unworn side of the plateau. Still, conversion between LLR size and real size should be adjusted using a mathematical calculation. The whole process of manual templating tech-

The more parallel the bone cut planes, the less ligament release is necessary. The less parallel the bone cut planes, the more ligament release is necessary. One must note that there is a limit for releasing ligaments. When a great amount of releasing is necessary, the surgeon should consider a more constrained implant, since it could get into a situation called "over resection

The size of the components can be also estimated during the planning of a TKA. To do it so, the surgeon must have the specific prosthesis templates and should order a short-leg X-ray in

Despite the fact that manual planning is an affordable method, it lacks portability. The surgeon must have manual tools such as a pencil; an eraser; a protractor; and rulers, big enough to measure the whole LLR film. Besides, the surgeon needs to make mathematical conversions

Considering the current computational resources used as tools to support medical practices, the paradigm known as *mHealth*, which consists of the use of mobile computing resources in health, stands out. When applied to favor teaching and learning processes, mobile technologies provide numerous benefits, such as increased resources for student learning, access to

should be used to make a conversion between film size and actual size.

looseness," when the ligament function capacity is exceeded.

**2.2. Digital planning using ATJ® mobile phone application**

and must comprehend a rational methodology of planning on TKA.

the AAF, referenced by MAFÂ.

4 Primary Total Knee Arthroplasty

nique is illustrated in **Figure 2**.

an actual size (1:1).

**Figure 2.** Manual templating. First, the anatomical and mechanical axis of the femur and tibia are defined. MAFÂ is measured by using a protractor. A perpendicular cut is measured from MAF and MAT. To correctly place the bone cut lines, the surgeon must mathematically convert printed LLR film size to real size. To do it, the surgeon needs manual tools such as pencil, eraser, rulers, protector, and goniometer.

textbooks anywhere, anytime, and the provision of resources for the development of innovative teaching methods [9]. By facilitating real-world integration, mobile learning aided by mobile computing (Mobile Learning or m-learning) has created opportunities for development of new teaching strategies in different areas [10].

An interdisciplinary team, involving health and computer science areas, developed an application (ATJ®) that is capable of conducting the surgeon though a step-by-step process (same described

#### 6 Primary Total Knee Arthroplasty

for manual planning) adapted for digital planning. Besides, explanations about rationality of the methodology and surgical tips on each step of planning were incorporated to the application. It is able to recognize the type of deformity (valgus or varus) and automatically measure MAFÂ.

**Figure 4.** After choosing between the left or right knee, the surgeon must inform the application in which size scale is adopted on LLR. By doing so, the surgeon does not need to make mathematical calculations, since the application is able

Planning Primary Total Knee Arthroplasties http://dx.doi.org/10.5772/intechopen.72775 7

It also suggests soft tissue releases, according to the deformity [11].

to convert LLR size to real size.

**Figure 3.** Fields of the medical register. They are available *offline* and *online,* in a cloud host.

Planning Primary Total Knee Arthroplasties http://dx.doi.org/10.5772/intechopen.72775 7

**Figure 4.** After choosing between the left or right knee, the surgeon must inform the application in which size scale is adopted on LLR. By doing so, the surgeon does not need to make mathematical calculations, since the application is able to convert LLR size to real size.

for manual planning) adapted for digital planning. Besides, explanations about rationality of the methodology and surgical tips on each step of planning were incorporated to the application. It is able to recognize the type of deformity (valgus or varus) and automatically measure MAFÂ. It also suggests soft tissue releases, according to the deformity [11].

**Figure 3.** Fields of the medical register. They are available *offline* and *online,* in a cloud host.

6 Primary Total Knee Arthroplasty

#### 8 Primary Total Knee Arthroplasty

**Figure 5.** The LLR should be uploaded from the device's camera roll or the device's camera can be used to acquire the LLR image (Figure Planning).

Before getting into planning, the surgeon is presented with a video that briefly describes the method used in the application. Fields of registration such as name, email, telephone, age, gender, medical record number, and date are available. The data are stored on the device and in a cloud host. Anytime, wherever the surgeon is, it is possible to access it from any computer if desired (**Figure 3**).

Planning starts by choosing the intended knee to be operated (left or right). After choosing the side, the application inquiries on size scale used on LLR, which is usually informed on LLR margins. This is an important step since the application needs to know the relation between the LLR film size and real size, avoiding the surgeon making mathematical conversions (**Figure 4**).

then takes the surgeon through the whole process of planning by inquiring the surgeon to point references (center of the femoral head, center of the medullary femoral canal, center of the intercondylar notch, center of the tibial spines, and center of the talus). After setting points, the application automatically defines AAF, MAF, MAFÂ, and MAT. It also positions a

**Figure 6.** Step-by-step planning process. After defining AAF, MAF, MAFÂ, and MAT, the surgeon should simulate the level and inclination of distal femoral and proximal tibial bone cuts. Application ATJ® is capable of automatically

Planning Primary Total Knee Arthroplasties http://dx.doi.org/10.5772/intechopen.72775 9

recognizing the knee-type deformity. It also suggests a sequence for ligament releasing.

The LLR can be acquired by two modes: uploading an image from device's camera roll or using the device's camera to photograph the LLR on a negatoscope (**Figure 5**). The application

Planning Primary Total Knee Arthroplasties http://dx.doi.org/10.5772/intechopen.72775 9


**Figure 6.** Step-by-step planning process. After defining AAF, MAF, MAFÂ, and MAT, the surgeon should simulate the level and inclination of distal femoral and proximal tibial bone cuts. Application ATJ® is capable of automatically recognizing the knee-type deformity. It also suggests a sequence for ligament releasing.

**Figure 5.** The LLR should be uploaded from the device's camera roll or the device's camera can be used to acquire the

Before getting into planning, the surgeon is presented with a video that briefly describes the method used in the application. Fields of registration such as name, email, telephone, age, gender, medical record number, and date are available. The data are stored on the device and in a cloud host. Anytime, wherever the surgeon is, it is possible to access it from any computer

Planning starts by choosing the intended knee to be operated (left or right). After choosing the side, the application inquiries on size scale used on LLR, which is usually informed on LLR margins. This is an important step since the application needs to know the relation between the LLR film size and real size, avoiding the surgeon making mathematical conversions (**Figure 4**). The LLR can be acquired by two modes: uploading an image from device's camera roll or using the device's camera to photograph the LLR on a negatoscope (**Figure 5**). The application

LLR image (Figure Planning).

8 Primary Total Knee Arthroplasty

if desired (**Figure 3**).

then takes the surgeon through the whole process of planning by inquiring the surgeon to point references (center of the femoral head, center of the medullary femoral canal, center of the intercondylar notch, center of the tibial spines, and center of the talus). After setting points, the application automatically defines AAF, MAF, MAFÂ, and MAT. It also positions a moveable bone cutting line, perpendicular to MAF and MAT. At the end of the methodology process, it automatically shows the type of deformity, the MAFÂ, and soft tissue releasing sequence (**Figure 6**). Then, scientific references used to build the application are presented.

The application ATJ® has proved to be useful in the context of planning TKA. It has revealed accuracy when measuring the MAFÂ when compared to the manual form of planning. It was also capable of reducing the planning time by more than a half [11, 12].
