Effect of limb rotation on radiographic alignment measurement in mal-aligned knees

Abstract Purpose Long-leg-radiography (LLR) is commonly used for the measurement of lower limb alignment. However, limb rotations during radiography may interfere with the alignment measurement. This study examines the effect of limb rotation on the accuracy of measurements based on the mechanical and anatomical axes of the femur and tibia, with variations in knee flexion and coronal deformity. Methods Forty-five lower limbs of 30 patients were scanned with CT. Virtual LLRs simulating five rotational positions (neutral, ± 10$$^{\circ }$$ ∘ , and ± 20$$^{\circ }$$ ∘ internal rotation) were generated from the CT images. Changes in the hip–knee–ankle angle (HKA) and the femorotibial angle (FTA) were measured on each image with respect to neutral values. These changes were related to knee flexion and coronal deformity under both weight- and non-weight-bearing conditions. Results The measurement errors of the HKA and FTA derived from limb rotation were up to 4.84 ± 0.66$$^{\circ }$$ ∘ and 7.35 ± 0.88$$^{\circ }$$ ∘ , respectively, and were correlated with knee flexion (p < 0.001) and severe coronal deformity (p < 0.001). Compared with the non-weight-bearing position, the coronal deformity measured in the weight-bearing condition was 2.62$$^{\circ }$$ ∘ greater, the correlation coefficients between the coronal deformity and the deviation ranges of HKA and FTA were also greater. Conclusions Flexion and severe coronal deformity have a significant influence on the measurement error of lower limb alignment. Errors can be amplified in the weight-bearing condition compared with the non-weight-bearing condition. When using HKA and FTA to represent the mechanical axis and the anatomical axis on LLR, limb rotation impacts the anatomic axis more than the mechanical axis in patients with severe deformities. Considering LLR as the gold standard image modality, attention should be paid to the measurement of knee alignment. Especially for the possible errors derived from weight-bearing long-leg radiographs of patients with severe knee deformities.

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Effect of limb rotation on radiographic alignment measurement in mal-aligned knees

10.21203/rs.3.rs-850458/v1 ◽

2021 ◽

Author(s):

Xiaoshu Sun ◽

Bin Yang ◽

Shengzhao Xiao ◽

Yichen Yan ◽

Zifan Liu ◽

...

Keyword(s):

Measurement Error ◽

Lower Limb ◽

Knee Flexion ◽

Weight Bearing ◽

Correlation Coefficients ◽

Lower Limbs ◽

Limb Alignment ◽

Lower Limb Alignment ◽

Accuracy Of Measurements ◽

Alignment Errors

Abstract PurposeLong-leg-radiography (LLR) is commonly used for measurement of lower limb alignment. However, limb rotations during radiography may interfere with the alignment measurement. This study examines the effect of limb rotation on the accuracy of measurements based on the mechanical and anatomical axes of the femur and tibia, with variations in knee flexion and coronal deformity. MethodsForty-five lower limbs of thirty patients were scanned with CT. Virtual LLRs simulating 5 rotational positions (neutral, ±10°, and ±20° internal rotation) were generated from the CT images. Changes in the hip-knee-ankle angle (HKA) and the femorotibial angle (FTA) were measured on each image with respect to neutral values. These changes were related to knee flexion and coronal deformity under both weight- and non-weight-bearing conditions. ResultsThe measurement error of the HKA and FTA derived from limb rotation were up to 4.84±0.66° and 7.35±0.88° respectively, and were correlated with knee flexion (p＜0.001) and severe coronal deformity (p≤0.001). Compared with non-weight-bearing position, coronal deformity measured in weight-bearing condition was 2.62° greater, the correlation coefficients between the coronal deformity and the deviation ranges of HKA and FTA were also greater. ConclusionFlexion and severe coronal deformity have significant influence on the measurement error of lower limb alignment. Errors can be amplified in the weight-bearing condition compared with the non-weight-bearing condition. The error of measurement of the anatomic axis is greater than the mechanical axis. Considering LLR is the gold standard image modality, attention should be paid to the measurement of knee alignment. Especially for the possible errors derives from weight-bearing long leg radiographs of patients with severe knee deformities.

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A motion analysis based technique for measuring frontal plane lower-limb alignment in patients with fixed knee flexion contractures

Gait & Posture ◽

10.1016/j.gaitpost.2014.04.100 ◽

2014 ◽

Vol 39 ◽

pp. S73

Author(s):

Adam Rozumalski ◽

Tom F. Novacheck ◽

Michael H. Schwartz

Keyword(s):

Motion Analysis ◽

Lower Limb ◽

Knee Flexion ◽

Frontal Plane ◽

Limb Alignment ◽

Lower Limb Alignment ◽

Flexion Contractures

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Can Deep Learning Using Weight Bearing Knee Anterio-Posterior Radiograph Alone Replace a Whole-Leg Radiograph in the Interpretation of Weight Bearing Line Ratio?

Journal of Clinical Medicine ◽

10.3390/jcm10081772 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1772

Author(s):

Hyun-Doo Moon ◽

Han-Gyeol Choi ◽

Kyong-Joon Lee ◽

Dong-Jun Choi ◽

Hyun-Jin Yoo ◽

...

Keyword(s):

Deep Learning ◽

Lower Limb ◽

Assessment Tool ◽

Weight Bearing ◽

Absolute Error ◽

Limb Alignment ◽

Lower Limb Alignment ◽

Test Set ◽

Cumulative Score ◽

Validation Set

Weight bearing whole-leg radiograph (WLR) is essential to assess lower limb alignment such as weight bearing line (WBL) ratio. The purpose of this study was to develop a deep learning (DL) model that predicts the WBL ratio using knee standing AP alone. Total of 3997 knee AP & WLRs were used. WBL ratio was used for labeling and analysis of prediction accuracy. The WBL ratio was divided into seven categories (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6). After training, performance of the DL model was evaluated. Final performance was evaluated using 386 subjects as a test set. Cumulative score (CS) within error range 0.1 was set with showing maximum CS in the validation set (95% CI, 0.924–0.970). In the test set, mean absolute error was 0.054 (95% CI, 0.048–0.061) and CS was 0.951 (95% CI, 0.924–0.970). Developed DL algorithm could predict the WBL ratio on knee standing AP alone with comparable accuracy as the degree primary physician can assess the alignment. It can be the basis for developing an automated lower limb alignment assessment tool that can be used easily and cost-effectively in primary clinics.

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Effects of Total Knee Arthroplasty on Coronal and Sagittal Whole-Body Alignments: Serial Assessments Using Whole-Body EOS

Journal of Clinical Medicine ◽

10.3390/jcm10153242 ◽

2021 ◽

Vol 10 (15) ◽

pp. 3242

Author(s):

Seong-Chan Kim ◽

Han-Gyeol Choi ◽

Joo-Sung Kim ◽

Tae-Woo Kim ◽

Yong-Seuk Lee

Keyword(s):

Knee Joint ◽

Lower Limb ◽

Weight Bearing ◽

Whole Body ◽

Limb Alignment ◽

Lower Limb Alignment ◽

Passive Motion ◽

X Ray ◽

Spinopelvic Alignment ◽

Total Knee

Background: The aims of this study were to evaluate the effects of correcting lower limb alignment by total knee arthroplasty (TKA) on the spinopelvic alignment and to identify patients with difference in the knee joint between clinically measured passive motion and the actual standing posture. Methods: In this retrospective study, 101 patients who underwent TKA and whose serial whole-body EOS X-ray were available were included. The relationship of the knee and spinopelvic alignment was analyzed by evaluating the parameters of standing anterior-posterior and lateral whole-body EOS X-ray. The differences between postoperative passive motion and weight-bearing posture in the knee joint were assessed in both coronal and sagittal planes. Furthermore, the causes of such differences were analyzed. Results: Significant correlations between Δpelvic obliquity and coronal ΔHip-Knee-Ankle (HKA)Rt-Lt angle between the preoperative and 3-month and 1-year postoperative data (p < 0.001 and p < 0.005, respectively) and improved with coronal lower limb alignment close to neutral resulted in decreased pelvic obliquity (p < 0.001, ß = 0.085 and p = 0.005, ß = 0.065, respectively) were observed. The correlations between Δpelvic tilt (PT) and Δsacral slope (SS) and sagittal ΔHKARt-Lt angle were statistically significant (PT: p < 0.001 and p < 0.045; SS: p = 0.002 and p < 0.001, respectively). The improved sagittal alignment close to neutral resulted in decreased PT and increased SS. The difference between postoperative passive motion and the weight-bearing posture of the knee joint was correlated with lumbar lordosis and sagittal C7 plumb line-sacrum distance (p = 0.042 and p < 0.001, respectively). Conclusions: The correction of lower limb alignment with TKA affected pelvic parameters dominantly; however, there was little effect on the spinal alignment. Additionally, patients with anterior stooping or lumbar flat back demonstrated difference in extension between passive knee motion and standing. Therefore, rather than only focusing on changes in the knee alignment correction, knee surgeons should also evaluate the spinopelvic alignment before surgery to consider the prognosis of the standing and predict the possible changes in the whole-body alignment. This preoperative assessment may improve the prognosis of TKA.

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2D-3D registration for 3D analysis of lower limb alignment in a weight-bearing condition

Applied Mathematics-A Journal of Chinese Universities ◽

10.1007/s11766-018-3459-2 ◽

2018 ◽

Vol 33 (1) ◽

pp. 59-70 ◽

Cited By ~ 1

Author(s):

Eungjune Shim ◽

Youngjun Kim ◽

Deukhee Lee ◽

Byung Hoon Lee ◽

Sungkyung Woo ◽

...

Keyword(s):

Lower Limb ◽

Weight Bearing ◽

3D Analysis ◽

3D Registration ◽

Limb Alignment ◽

Lower Limb Alignment

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Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors

The Journal of Knee Surgery ◽

10.1055/s-0039-1693668 ◽

2019 ◽

Vol 34 (01) ◽

pp. 108-114

Author(s):

Günther Maderbacher ◽

Jan Matussek ◽

Felix Greimel ◽

Joachim Grifka ◽

Jens Schaumburger ◽

...

Keyword(s):

Lower Limb ◽

Measurement Errors ◽

Orthopaedic Surgery ◽

Proximal Tibia ◽

External Rotation ◽

Weight Bearing ◽

Lower Limbs ◽

Before And After ◽

Mean Differences ◽

Long Leg Radiographs

AbstractWeight-bearing long-leg radiographs are commonly used in orthopaedic surgery. Measured parameters, however, change when radiographs are conducted in different rotational positions of the leg. It was hypothesized that rotational errors are regularly present in long-leg radiographs resulting in wrong measurements. In 100 consecutive long-leg radiographs conducted according to the method of Paley, rotation was assessed by fibular overlap. Angular parameters in radiographs (mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle between the anatomical and mechanical femoral axis (AMA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), and the mechanical femoral and tibial axis (mFA–mTA) were measured and deviations related to malrotation calculated. An average internal rotation of 8 degrees was found in lower limbs showing a range between 29 degrees of internal and 22 degrees of external rotation. As a result, mean differences before and after rotational correction for measured parameters (mLPFA, mLDFA, AMA, mMPTA, mLDTA, mFA–mTA) ranged between 0.4 and 1.7 degrees (−2.1; 5.6 95% confidence interval [CI]). In conclusion, malrotation of lower limbs is regularly present in long-leg radiographs. As all measured parameters are influenced by malrotation, correct lower limb rotation needs to be verified.

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The fracture sites of atypical femoral fractures are associated with the weight-bearing lower limb alignment

Bone ◽

10.1016/j.bone.2014.06.008 ◽

2014 ◽

Vol 66 ◽

pp. 105-110 ◽

Cited By ~ 45

Author(s):

Yoshitomo Saita ◽

Muneaki Ishijima ◽

Atsuhiko Mogami ◽

Mitsuaki Kubota ◽

Tomonori Baba ◽

...

Keyword(s):

Lower Limb ◽

Weight Bearing ◽

Femoral Fractures ◽

Limb Alignment ◽

Lower Limb Alignment ◽

Atypical Femoral Fractures

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Analysis of The Global Posture of College Students With Chronic Neck Pain

10.21203/rs.3.rs-1089151/v1 ◽

2021 ◽

Author(s):

Jiugen Zhong ◽

Wenhao Wang ◽

Ligen Yu ◽

Xiaohui Hou

Keyword(s):

Risk Factors ◽

College Students ◽

Neck Pain ◽

Lower Limb ◽

Knee Flexion ◽

Sagittal Plane ◽

Chronic Neck Pain ◽

Control Group ◽

Limb Alignment ◽

Lower Limb Alignment

Abstract Background: Chronic neck pain (CNP) is common, but methods that focus on the cervical spine have not met the patients' medical expectations.Objective: To investigate the global postural difference between students with CNP and healthy people.Design: Cross-sectional study.Methods: Twenty-seven healthy college students without neck pain and 31 students with CNP were recruited and allocated into a control group and a CNP group. Differences in standing postural indicators between the two groups were compared.Results: Compared to the control group, the leg length discrepancy and the right rearfoot angle were larger and the anterior lower limb alignment angle was smaller. In the sagittal plane, the left sagittal lower limb alignment and right cervical alignment angles were larger, while the left and right sagittal body alignment angles in the CNP group were smaller. The odds ratio calculation for the trunk forward lean, right foot valgus, and knee flexion on both sides indicated that these are risk factors for CNP, while knee varus is not a risk factor for CNP. The remaining abnormal postures were shown not to be associated with CNP.Limitation: This study did not conduct in-depth research on the physiological state of the muscles, joints, and other structures, and we did not apply these theories to practice.Conclusions: Abnormal posture in students with CNP is mainly concentrated in the sagittal plane. Trunk forward lean, foot valgus, and knee flexion on both sides are risk factors for CNP.

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Lower Limbs Alignment in Patients with a Unilateral Completely Dislocated Hip

The Open Orthopaedics Journal ◽

10.2174/1874325001610010448 ◽

2016 ◽

Vol 10 (1) ◽

pp. 448-456 ◽

Cited By ~ 4

Author(s):

Shinsuke Someya ◽

Motoki Sonohata ◽

Shuya Ide ◽

Satomi Nagamine ◽

Tomonori Tajima ◽

...

Keyword(s):

Lower Limb ◽

Hip Osteoarthritis ◽

Lower Limbs ◽

Osteoarthritis Of The Knee ◽

Leg Length ◽

Limb Alignment ◽

Lower Limb Alignment ◽

Unaffected Side ◽

Secondary Osteoarthritis ◽

Valgus Alignment

Background: Severe hip osteoarthritis is known to lead to secondary osteoarthritis of the knee joint. It is not clear whether contracture or a leg length discrepancy is more important in determining the knee alignment. Methods: In this study, 48 hips in 48 patients with a unilateral completely dislocated hip (Crowe IV) were recruited. The patients were divided into two groups (Crowe IVa and IVb). The Crowe IVa group had completely dislocation with psudo-articulation, and the Crowe IVb group had completely dislocation without psudo-articulation. The lower limb alignment was divided into three patterns according to the femorotibial angle; varus (≥176 degrees), neutral(170 to 175 degrees) and valgus(≤169 degrees). Results: The combination of valgus alignment on the affected side and varus alignment on the unaffected side, so-called “windswept deformity” was observed in 12.5% of the patients; this included 18.2% and 7.7%, in the Crowe IVa and Crowe IVb groups, respectively. The valgus alignment on the unaffected side, namely “long leg arthropathy,” was found to have occurred in 6.3% of the patients, including 13.6% of the patients in the Crowe IVa group; there were no cases of long “leg arthropathy” in the Crowe IVb group. Conclusion: The lower limb alignment on the unaffected side had a tendency to be varus in the Crowe IV patients. The “windswept deformity” was observed in each of the groups; however, “long leg arthropathy” was only found in the Crowe IVa group.

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