Distal femoral cut perpendicular to the mechanical axis may induce varus instability in flexion in medial osteoarthritic knees with varus deformity in total knee arthroplasty: a pitfall of the navigation system

Nagamine, Ryuji; Kondo, Keiichi; Ikemura, Satoshi; Shiranita, Atsushi; Nakashima, Satoshi; Hara, Toshihiko; Ihara, Hidetoshi; Sugioka, Yôichi

doi:10.1007/s00776-004-0818-z

Cited by 29 publications

(32 citation statements)

References 12 publications

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“…In these cases, if the distal femoral cut is made perpendicular to the mechanical axis of the femur, there would be a great amount of bone resection on the lateral side. For the ligament balancing in these cases, extra release of the medial soft tissue structures is needed, which leads to flexion instability (14). In another study valgus cuts based on FMA of each patient led to better limb alignment after surgery (15).…”

Section: Discussionmentioning

confidence: 99%

Is it Safe to Use a Six-Degree Distal Femoral Valgus Cut in All Genu Varus Patients with Total Knee Arthroplasty?

et al. 2017

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Background: During a total knee arthroplasty, it is common to make a distal femoral cut based on the femoral mechanicalanatomical angle (FMA), which in most patients is six degrees. However, in patients with a higher FMA, there is not yet a consensus between surgeons regarding the degree of the cutting angle. Objectives: The aim of this study is to assess the treatment outcomes of patients with a FMA of more than seven degrees who were treated by distal femoral cuts of six degrees during a total knee arthroplasty. Methods: We retrospectively reviewed the clinical and radiological results of patients who were treated at our center by a conventional valgus cut of six degrees during a total knee arthroplasty and had a FMA of more than seven degrees. A knee society score (KSS) was completed for all patients during follow-up visits. Results: A total of 31 cases with knee osteoarthritis and a FMA of more than seven degrees were enrolled in this study. The cases

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Section: Discussionmentioning

confidence: 99%

Is it Safe to Use a Six-Degree Distal Femoral Valgus Cut in All Genu Varus Patients with Total Knee Arthroplasty?

et al. 2017

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“…Lateral bowing of the femur tends to increase the difference between the mechanical axis and the anatomical axis of the femur [29], which results in a large number of outliers in the computer-assisted group. If the distal femur is cut perpendicular to the mechanical axis in knees with lateral bowing of the femur, the distal femoral cut can be in a more valgus position [29]. Therefore, distal femoral cut in computer-assisted TKA needs to be modified when severe lateral bowing of the femur is observed on preoperative radiographs [29].…”

Section: Discussionmentioning

confidence: 99%

“…If the distal femur is cut perpendicular to the mechanical axis in knees with lateral bowing of the femur, the distal femoral cut can be in a more valgus position [29]. Therefore, distal femoral cut in computer-assisted TKA needs to be modified when severe lateral bowing of the femur is observed on preoperative radiographs [29].…”

Section: Discussionmentioning

confidence: 99%

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Comparison of the radiological results between fluoroscopy-assisted and navigation-guided total knee arthroplasty

Jung

Lee

Jung

et al. 2008

Knee Surg Sports Traumatol Arthrosc

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The efficacy and accuracy of computer navigation have been proved during recent years. But most of recent studies focused on the coronal alignment in total knee arthroplasty and less on sagittal alignment. We retrospectively compared the results of the radiographs of 35 primary TKAs using a non-image based navigation system and 36 primary TKAs using fluoroscopy-assisted conventional technique. To compare the radiographic results, the following parameters were measured: mean mechanical femorotibial angle, mean femorotibial anatomical angle, mean coronal femoral component angle, mean coronal tibial component angle, mean sagittal femoral component angle, and mean sagittal tibial component angle. The navigation TKA showed better accuracy and consistency in mechanical axis deviation, coronal femoral component angle, and sagittal tibial component angle. The coronal tibial component position was acceptable in both groups. The navigation TKA markedly improved the restoration of mechanical axis, but not so much in sagittal femoral component position. The fluoroscopy-assisted conventional TKA had a tendency that femoral component was inserted in flexed position than in navigation TKA. Unlike the fluoroscopy-assisted conventional TKA, the femoral component was inserted in slightly extended position in the navigation TKA than expected. In conclusion, even though the use of navigation in TKAs help the surgeon to achieve good results, the surgeon should know the tendency of extension of the femoral component in sagittal plane to avoid anterior notching.

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“…However, TKA is associated with high rates of revision reoperation after the primary arthroplasty (Pabinger et al, 2013). According to some reports, abnormal varus or valgus alignment may lead to loosening of the implants (Oswald et al, 1993;Nagamine et al, 2004). Thus, a key to minimizing the TKA failure rate is to reestablish the normal mechanical alignment of the knee joint, while preventing any abnormal varus or valgus errors.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional reconstruction method for measuring the knee valgus angle of the femur in northern Chinese adults

Liu

Wang

Xiao

et al. 2014

J. Zhejiang Univ. Sci. B

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Abstract:The purpose of this study was to establish a method for measuring the knee valgus angle from the anatomical and mechanical axes on three-dimensional reconstruction imaging models, and to use this method for estimating an average knee valgus angle value for northern Chinese adults. Computed tomographic angiography data in DICOM format for 128 normal femurs from 64 adult subjects were chosen for analysis. After the femur images were subjected to three-dimensional reconstruction, the deepest point in the intercondylar notch (point A), the midpoint of the medullary cavity 20 cm above the knee-joint line (point B), and the landmark of the femoral head rotation center (point C) were identified on each three-dimensional model. The knee valgus angle was defined as the angle enclosed by the distal femoral anatomical axis (line AB) and the femoral mechanical axis (line AC). The average (mean±SD) of knee valgus angle for the 128 femurs was 6.20°±1.20° (range, 3.05° to 10.64°). Significant positive correlations were found between the knee valgus angles of the right and left sides and between the knee valgus angle and age. During total knee arthroplasty, choosing a valgus cut angle of approximately 6° may achieve a good result in reestablishing the natural mechanical alignment of the lower extremity for patients of northern Chinese ethnicity. Larger valgus cut angles should be chosen for older patients.

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Distal femoral cut perpendicular to the mechanical axis may induce varus instability in flexion in medial osteoarthritic knees with varus deformity in total knee arthroplasty: a pitfall of the navigation system

Cited by 29 publications

References 12 publications

Is it Safe to Use a Six-Degree Distal Femoral Valgus Cut in All Genu Varus Patients with Total Knee Arthroplasty?

Is it Safe to Use a Six-Degree Distal Femoral Valgus Cut in All Genu Varus Patients with Total Knee Arthroplasty?

Comparison of the radiological results between fluoroscopy-assisted and navigation-guided total knee arthroplasty

Three-dimensional reconstruction method for measuring the knee valgus angle of the femur in northern Chinese adults

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