Intraoperative Soft Tissue Balance/Kinematics and Clinical Evaluation of Modified Kinematically versus Mechanically Aligned Total Knee Arthroplasty

Abstract

<jats:title>Abstract</jats:title><jats:p>Recently, kinematically aligned total knee arthroplasty has been found to achieve better clinical outcomes than mechanically aligned TKA. Despite the good clinical outcomes that are reported at short- to mid-term follow-up, intraoperative variables that are associated with a better outcome have not been measured. Therefore, this study was conducted to compare intraoperative kinematics/soft tissue balance and the clinical outcomes of patients who underwent modified kinematically (restricted tibial cut) or mechanically aligned total knee arthroplasty. Sixty cruciate-retaining total knee arthroplasties (30 modified kinematically [3-degree varus and 7-degree posterior slope in tibial cut] and 30 mechanically aligned) were performed in patients with varus-type osteoarthritis using a navigation system. Intraoperative kinematics assessed by the navigation system and soft tissue balance assessed by an offset-type tensor were compared between the groups. One year postoperatively, the range of motion and 2011 Knee Society scores were compared between the groups. Kinematic assessment exhibited that tibial internal rotation during flexion was significantly maintained in the kinematic compared with the mechanical group (p &lt; 0.05). Varus/valgus ligament balance at 90 and 120 degrees of flexion significantly maintained lateral laxity in the kinematic compared with the mechanical group (p &lt; 0.05). Improvement of flexion angles, functional activity scores, and patient satisfaction were significantly better in the kinematic than in the mechanical group (p &lt; 0.05). Modified kinematically aligned cruciate-retaining total knee arthroplasty maintained more tibial internal rotation and lateral laxity during flexion than mechanically aligned total knee arthroplasty; thus, the former may result in better clinical outcomes.</jats:p>

Kinematic alignment versus mechanical alignment in primary total knee arthroplasty: an updated meta-analysis of randomized controlled trials

“…However, we also discovered no significant differences in KSS (function) between the KA and MA groups (MD = 4.86, 95% CI − 0.50 to 10.23, I 2 = 72%, Fig. 3 c) [ 19 , 20 , 24 – 26 , 29 , 30 , 34 ]. After gradually removing these eight studies, we found no significant change in heterogeneity, indicating that the pooled analysis results of KSS (function) were stable (Table 2 ).…”

“…As shown in Fig. 3 a, eight studies with 572 patients were included in the KSS (knee) evaluation [ 19 , 20 , 24 , 25 , 27 , 29 , 30 , 34 ]. The pooled MD was 3.24 (95% CI 0.46–6.03), and I 2 was 59%.…”

“…8 b), which means that the FKA of the KA group was significantly greater than that of the MA group. Nine studies [ 19 , 20 , 24 , 26 , 28 , 29 , 31 , 33 , 35 ] compared the mLDFA. The pooled results indicated no significant difference between the two groups (MD = − 0.93, 95% CI − 2.23–0.36, I 2 = 95%, Fig.…”

Kinematically Aligned Total Knee Arthroplasty Using Medial Pivot Knee Prosthesis Enhances Medial Pivot Motion: A Comparative Kinematic Study With Mechanically Aligned Total Knee Arthroplasty

“…The kinematic path of the medial pivot pattern was substantially confirmed in MA-TKA but was much smaller than that in normal healthy knees [ 18 ]. Based on the perspectives of intraoperative gap balance, greater tibial internal rotation and lateral laxity during knee flexion were observed in KA-TKA than in MA-TKA [ 19 ]. In our study, the degree of medial pivot motion seemed sufficient in KA-TKA using a medial pivot knee prosthesis, but paradoxical femoral anterior sliding at early flexion still existed.…”

Rotational and varus–valgus laxity affects kinematics of the normal knee: A cadaveric study

“…7 According to Matsumoto et al, kinematically aligned cruciate retaining TKA maintained more tibial internal rotation and lateral laxity during flexion than mechanically aligned TKA. 25 Even though meticulous TKA studies have been conducted, it is necessary to understand the relationship between the soft tissue laxity and kinematics in normal knee. In this study, the rotation angle of the tibia was correlated to the intermediate angle of IE laxity at 0°, 30°, 60°, and 90° of knee flexion, and the coronal alignment of the lower limb also correlated to the intermediate angle of VV laxity.…”