An Additional Reference Axis Improves Femoral Rotation Alignment in Image-Free Computer Navigation Assisted Total Knee Arthroplasty
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Materials and Methods
Institutional review board approval was received for this study. All patients provided written informed consent.
Of a total of 162 consecutive primary TKA procedures performed in 146 patients between January 2009 and September 2011, 158 knees were replaced using the Stryker 4.0 image-free computer navigation system (Stryker Orthopedics, Mahwah, NJ) equipped with an average algorithm derived from the registered the Whiteside axis and SEA.
Between January 2009 and June 2010, femoral rotational
Results
The average RFC angle was − 0.1° ± 2.4° [mean ± SD, range: 7° of internal rotation to 4° of external rotation] for the double-axis group and 0.3° ± 1.7° (3° of external rotation to 3° of internal rotation) for the triple-axis group. With regard to the average RFC angle, there were no statistically significant differences observed between the two groups.
Thirty-one cases (82%) were implanted ideally (within 3° of neutral) in the double-axis group, whereas all 26 cases (100%) were implanted ideally in
Discussion
Malpositioning of any component can lead to an increased risk of loosening, instability, and pain 3., 4.. Restoration of the tibiofemoral angle to within 3° of neutral during TKA is thought to be associated with a better outcome 4., 5., 6., 21., 22.. Computer-assisted navigation systems are designed to increase the accuracy of implantation, and have become much more accepted and prevalent in recent years. Several studies have demonstrated superior alignment of the components in the coronal
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Cited by (20)
Intraoperative kinematics of bicruciate-stabilized total knee arthroplasty during high-flexion motion of the knee
2021, KneeCitation Excerpt :The femur was aligned at 90° to the mechanical axis in the frontal plane with 4° of flexion in the sagittal plane, while the tibia was aligned similarly in the frontal plane with 3° of posterior slope in the sagittal plane. The femoral rotation was determined as being parallel to the surgical epicondylar axis and tibial rotation was determined using the ROM technique [18,19]. After implantation, we measured intraoperative knee kinematics using a navigation system (Precision N; Stryker Orthopedics, Mahwah, NJ) that has been confirmed as accurate by a previous study [18].
Morphometry of femoral rotation for total knee prosthesis according to gender in a Korean population using three-dimensional magnetic resonance imaging
2016, KneeCitation Excerpt :Recently, Inui et al. suggested that an additional reference axis, which was calculated using image-free navigation, is required to define femoral rotation using SEA and WL if the patient suffered from trochlear dysplasia or destructive arthritis, leading to the wide difference. Based on this technique, the condylar twist angle, which is the angle between the SEA and the posterior condylar axis, was measured, and all 26 (100%) femoral prostheses implanted based on these three reference axes resulted in satisfactory postoperative outcomes [34]. The amounts and levels of bone resection with SEA and WL as references were compared using 3D surgical simulation, and significant differences were observed in the anterior and posterior bone cuttings with respect to gender.
Automating the design of resection guides specific to patient anatomy in knee replacement surgery by enhanced 3D curvature and surface modeling of distal femur shape models
2014, Computerized Medical Imaging and GraphicsCitation Excerpt :Among different CL of the distal femur, the intercondylar anterior–posterior axis, also known as Whiteside line (WL), is the target of this work. It is commonly adopted as a reference line to the determination of the knee flexion–extension axis and for positioning the femoral component on the axial plane altogether [11–20] or alternatively to the posterior condylar line (PCL) and the trans-epicondylar axis (TEA) in severely valgus knees [21,22]. High correlation of the WL direction with respect to that of the posterior condylar line for both varus and valgus knees was reported as well [23].
Rotational alignment in total knee arthroplasty
2013, Seminars in Arthroplasty JSESCitation Excerpt :Stockl et al. [27] used optical navigation to improve the mechanical axis, posterior tibial slope, and rotational alignment in primary TKA. Inui et al. [28] showed that addition of a third reference point in image-free navigation improves the accuracy of femoral component rotation. In contrast, a study by Lad et al. [29] did not demonstrate any improvement in rotational alignment or functional improvement using computer-assisted vs jig-based surgery.
Radiographical post-operative flexion gap balance was improved using a modified gap-balancing technique in navigation-assisted total knee arthroplasty
2020, Journal of Arthroscopy and Joint SurgeryCitation Excerpt :After cutting the distal femur, the posterior reference guide was set. To improve the accuracy of the femoral component rotation, an additional reference axis was applied as per Inui et al.11 We confirmed that the femoral component rotation, which was defined as the average rotational axis of the transepicondylar axis and the axis perpendicular to the Whiteside axis, was the same as the rotation on the pre-operative X-ray. In the NAMR group, femoral rotation cutting was performed using bony landmarks, such as the area perpendicular to the Whiteside axis and the surgical epicondylar axis, using a posterior reference cutting block under navigation guidance.
The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2013.01.030.