**2.1. Knee physical examination**

the normal mechanical axis of the knee and the balance of the surrounding soft tissues have to be observed to be important for the final outcome of knee replacement operations [2–5]. Thus, the severely valgus deformed knees are associated with a worse outcome when com-

The etiologic parameters of knee VD are different and multifactorial from congenital to secondary such as primary osteoarthritis. More specifically, inflammatory arthritis (rheumatic diseases), primary osteoarthritis, posttraumatic arthritis (as a result of a tibial malunion, physeal arrest, or tibial plateau fracture), or overcorrection from a high tibial osteotomy for a preexisting varus deformity are the main etiologies in adults with [2, 6]. However, a significant percentage of adults with lateral compartment arthritis and concomitant VD represents unresolved physiologic valgus deformed knees. Infrequently, persistence of genu valgus from childhood may exist secondary to metabolic disorders, such as rickets and renal osteodystrophy [7]. Overwhelmingly, the most common etiology of VD knees is primary osteoarthritis and secondly rheumatoid arthritis and posttraumatic arthritis, whereas other inflammatory disorders and osteonecrosis are scarce etiologies based on the main clinical series that utilized TKA in the last two decades [1–5, 8–16]. The valgus deformity is sustained by anatomical variations divided into bone remodeling and soft tissue contraction/elongation, and usually it is a combination of primary or secondary bone and soft-tissue abnormalities. These include contracted lateral capsular and ligamentous structures, lax medial structures, and acquired or preexisting bony anatomic deficiencies. This constellation of pathology makes attaining soft-tissue balance when the knee is returned to physiologic alignment extremely difficult [2, 4, 6]. More specifically, the contracted structures are the iliotibial band (ITB), the lateral collateral ligament (LCL), the popliteus tendon, and the posterolateral capsule (PLC). Rarely, the lateral head of the gastrocnemius and the long head of the biceps femoris are affected. Some authors also further described a posterior cruciate ligament (PCL) alteration in valgus knees, but in the literature its influence in maintaining the deformity is not universally accepted [2]. The stabilizing structures on the medial side of the knee are attenuated. Unlike its varus counterpart, bone tissue variations consist of lateral cartilage erosion, lateral condylar hypoplasia and metaphyseal femur remodeling, while the tibial plateau is usually less affected [2, 3, 8–10]. The described deformities can lead to a tibial

external rotation and to a patellar lateral subluxation tendency [11].

constrained implant usually is required [1, 10].

In 2005, Ranawat described three grades of VD [1]. More specifically, in Grade-I (80%), the deformity is less than 10° and is passively correctable, whereas it is characterized by an intact medial collateral ligament (MCL). In Grade-II (15%), the axis deviation ranges between 10° and 20°, whereas the MCL is elongated but functional; and in Grade-III (5%), the axis deviation is more than 20°. All the medial stabilizing elements are typically not functional so a

Understanding the specific pathologic anatomic changes associated with the valgus knee is a prerequisite so as to select the proper surgical method, to optimize component position and restore soft-tissue and gap balance [17]. Over the last 20 years, numerous approaches and soft-tissue procedures have been proposed to perform TKA in VD with the purpose to restore and maintain the limb's anatomical axis. In this chapter, we overview the most common approaches, we analyze the different techniques of succeeding anatomical axis restoration and soft tissue and gap balance, and lastly we present the literature up-to-date long-term results.

pared with their varus counterparts [5].

56 Primary Total Knee Arthroplasty

Patients with end-stage degenerative joint disease and valgus knee deformity have significant pain, limitation of daily living activities, increasing angular deformity, and increasing instability. In mild to severe VD, there is important ROM limitation, and in many cases night pain awakes the patient.

During standard physical examination for end-stage degenerative knee disease, the orthopedic physician should assess the patient's overall alignment both in the supine and weight-bearing positions, and the gait should be observed, in order to identify other dynamic instabilities (**Figure 1**). Both sagittal deformity (as fixed flexion contracture or recurvatum) and rotational deformity must be attended. Furthermore, the knee range of motion should be measured; the

**Figure 1.** Valgus left knee in standing position.

extensor mechanism status and the patellofemoral joint should be evaluated and measured [2, 6, 11].

orientation of the patella is very useful and important [3]. It has been mentioned that rotation

Primary Total Knee Arthroplasty in Valgus Deformity http://dx.doi.org/10.5772/intechopen.74114 59

Based on our experience, in cases of serious bone stock deficiency, a knee computer tomography will be helpful. Attention should be paid to lateral distal femoral hypoplasia, posterior femoral condyle erosion and metaphyseal remodeling both of the femur and tibia, which can lead to malalignment or malrotation of the femoral component and which could be better

The anteroposterior and lateral X-ray views would further aid to evaluate the amount of osseous resection needed to correct deformities without leading to knee instability. A precise knee profile view is helpful for assessing the tibial slope, and the height of the patella (alta or baja) based on the Insall-Salvati ratio. In addition, the 30° flexion patellofemoral view will help to

In order to measure the VD level and plan the amount of surgical correction (templating), a weight-bearing long leg X-ray view is fundamental so as to evaluate the lower limb alignment (mechanical and anatomical axis) (**Figure 3**). Stress radiographs or fluoroscopic examination may be used to determine the amount of medial instability [2]. A baseline electromyogram should be made for patients presenting with symptoms such as hypoesthesia, dysesthesia,

In the radiographic weight-bearing anteroposterior view of the knee, a template of bone cuts should be performed in consideration with the prosthesis type and design that will be implanted in the candidate for TKA. Two lines are drawn: one line on the tibial anatomical axis and afterward a perpendicular one at the level of the lateral tibial plateau. In that way, the surgeon will have an indication for the tibial resection [2, 4]. Firstly, the femoral anatomical axis is drawn and secondly the line with the desired amount of remaining valgus (usually 3°) at the level of the intercondylar notch [4]. The orthopedic surgeon should also observe the

up to 20° has little effect on the measurement of the femorotibial axis deviation [19].

measured with CT. The patellofemoral joint may also be partially dislocated.

evaluate if patella is centered in troxilia (centered, subluxation, luxation) [2, 11, 20].

and paresthesia that may be attributed to lumbosacral disease [2, 11].

**Figure 3.** Anteroposterior X-rays in standing position of Valgus knees in different grades.

**2.3. Templating**

In addition, preoperative clinical examination plays a major role for the orthopedic surgeon to determine whether the deformity is fixed, correctable or unstable. The knee should be further evaluated for anteroposterior laxity, coronal and sagittal deformity, and mediolateral instability [3]. It is very crucial to assess if VD is fixed (Ranawat Grade III) or still reducible (Ranawate Grade II or I). In fixed deformity, the lateral structures are tight and in contrast the medial ligaments are partially continent. As a consequence, in these deformities, when the lateral soft tissue release is fulfilled, the remaining laxity requires the usage of constrained prosthesis. In contrast, in a reducible deformity, soft tissue release is less invasive, and a standard unconstrained prosthesis could be used. The orthopedic surgeon would lastly perform a neurovascular examination to differentiate a possible lumbosacral or vascular disease [2, 9–11].

#### **2.2. Radiographic evaluation**

After the clinical assessment, the mandatory preoperative planning radiographs of three classic views of the affected knee are: standing anteroposterior, lateral (profile), and sunrise (**Figure 2**). The limb axis deviation measurement with long film standing views or CT-scan with anterior

**Figure 2.** Anteroposterior X-ray in standing position for measuring valgus deviation.

orientation of the patella is very useful and important [3]. It has been mentioned that rotation up to 20° has little effect on the measurement of the femorotibial axis deviation [19].

Based on our experience, in cases of serious bone stock deficiency, a knee computer tomography will be helpful. Attention should be paid to lateral distal femoral hypoplasia, posterior femoral condyle erosion and metaphyseal remodeling both of the femur and tibia, which can lead to malalignment or malrotation of the femoral component and which could be better measured with CT. The patellofemoral joint may also be partially dislocated.

The anteroposterior and lateral X-ray views would further aid to evaluate the amount of osseous resection needed to correct deformities without leading to knee instability. A precise knee profile view is helpful for assessing the tibial slope, and the height of the patella (alta or baja) based on the Insall-Salvati ratio. In addition, the 30° flexion patellofemoral view will help to evaluate if patella is centered in troxilia (centered, subluxation, luxation) [2, 11, 20].

In order to measure the VD level and plan the amount of surgical correction (templating), a weight-bearing long leg X-ray view is fundamental so as to evaluate the lower limb alignment (mechanical and anatomical axis) (**Figure 3**). Stress radiographs or fluoroscopic examination may be used to determine the amount of medial instability [2]. A baseline electromyogram should be made for patients presenting with symptoms such as hypoesthesia, dysesthesia, and paresthesia that may be attributed to lumbosacral disease [2, 11].
