Influence of axial limb rotation on radiographic lower limb alignment: a systematic review

Ahrend, Marc-Daniel; Baumgartner, H.; Ihle, Christoph; Histing, Tina; Schröter, Steffen; Finger, Felix

doi:10.1007/s00402-021-04163-w

Cited by 29 publications

(22 citation statements)

References 65 publications

(259 reference statements)

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“…Many patients with axial deformities, osteoarthritis, total knee arthroplasty (TKA) or other causes of partial immobility cannot fully extend their knees. Yet, 2D X-ray projection images change depending on the patient’s position and are influenced by rotation and flexion [ 1 , 5 , 8 , 11 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Significant changes in lower limb alignment due to flexion and rotation—a systematic 3D simulation of radiographic measurements

Brunner¹,

Jörgens²,

Weigert

et al. 2023

Knee Surg Sports Traumatol Arthrosc

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Background Many radiographic lower limb alignment measurements are dependent on patients’ position, which makes a standardised image acquisition of long-leg radiographs (LLRs) essential for valid measurements. The purpose of this study was to investigate the influence of rotation and flexion of the lower limb on common radiological alignment parameters using three-dimensional (3D) simulation. Methods Joint angles and alignment parameters of 3D lower limb bone models (n = 60), generated from computed tomography (CT) scans, were assessed and projected into the coronal plane to mimic radiographic imaging. Bone models were subsequently rotated around the longitudinal mechanical axis up to 15° inward/outward and additionally flexed along the femoral intercondylar axis up to 30°. This resulted in 28 combinations of rotation and flexion for each leg. The results were statistically analysed on a descriptive level and using a linear mixed effects model. Results A total of 1680 simulations were performed. Mechanical axis deviation (MAD) revealed a medial deviation with increasing internal rotation and a lateral deviation with increasing external rotation. This effect increased significantly (p < 0.05) with combined flexion up to 30° flexion (− 25.4 mm to 25.2 mm). With the knee extended, the mean deviation of hip–knee–ankle angle (HKA) was small over all rotational steps but increased toward more varus/valgus when combined with flexion (8.4° to − 8.5°). Rotation alone changed the medial proximal tibial angle (MPTA) and the mechanical lateral distal femoral angle (mLDFA) in opposite directions, and the effects increased significantly (p < 0.05) when flexion was present. Conclusions Axial rotation and flexion of the 3D lower limb has a huge impact on the projected two-dimensional alignment measurements in the coronal plane. The observed effects were small for isolated rotation or flexion, but became pronounced and clinically relevant when there was a combination of both. This must be considered when evaluating X-ray images. Extension deficits of the knee make LLR prone to error and this calls into question direct postoperative alignment controls. Level of evidence III (retrospective cohort study).

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Section: Introductionmentioning

confidence: 99%

Significant changes in lower limb alignment due to flexion and rotation—a systematic 3D simulation of radiographic measurements

Brunner¹,

Jörgens²,

Weigert

et al. 2023

Knee Surg Sports Traumatol Arthrosc

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“…Full weight-bearing anteroposterior (ap) X-rays of the whole lower limb were acquired with the leg in neutral rotation, the patella facing straight forward, the fibular head covered by the tibia for one third, and correct projection of the trochanter minor and ankle, to minimize measurement inaccuracies caused by internal or external lower leg malrotation in varus or valgus osteoarthritis [20][21][22]. Lateral radiographs of the standing knee were also taken.…”

Section: Radiologic Analysismentioning

confidence: 99%

Functional gait analysis reveals insufficient hindfoot compensation for varus and valgus osteoarthritis of the knee

Rühling

Kirschbaum

Perka

et al. 2023

International Orthopaedics (SICOT)

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Purpose The hindfoot is believed to compensate varus and valgus deformities of the knee by eversion and inversion movements. But these mechanisms were merely found in static radiologic measurements. The aim of this study was, therefore, to assess dynamic foot posture during gait using pressure-sensitive wireless insoles in patients with osteoarthritis of the knee and frontal knee deformities. Methods Patients with osteoarthritis of the knee were prospectively included in this study. Patients were clinically and radiologically (mechanical tibiofemoral angle (mTFA), hindfoot alignment view angle (HAVA), and talar tilt (TT)) exa mined. Gait line analysis was conducted using pressure-sensitive digital shoe insoles. Results Eighty-two patients (varus n = 52, valgus n = 30) were included in this prospective clinical study. Radiologically, the mTFA significantly correlated with the HAVA (cor = −0.72, p < 0.001) and with the TT (Pearson’s cor = 0.32, p < 0.006). Gait analysis revealed that the gait lines in varus knee osteoarthritis were lateralized, despite the hindfoot valgus. In valgus knee osteoarthritis, gait lines were medialized, although the hindfoot compensated by varization. Conclusions Functional dynamic gait analysis could demonstrate that the hindfoot is not able to sufficiently compensate for frontal malalignments of the knee joint, contrary to static radiologic findings. This led to a narrowing of the joint space of the ankle medially in varus and laterally in valgus knee osteoarthritis.

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“…Conventionally, these angles are measured on 2-dimensional (2D) radiographs to define the malalignment in the frontal and sagittal planes. The introduction of 3-dimensional (3D) imaging and planning now enables more accurate quantification of bone geometry, in particular the tibial and femoral torsion 2,3 . Additionally, it enables the use of image-based guidance technologies and personalized surgical cutting guides and implants that could increase surgical accuracy and efficiency 4-7 .…”

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confidence: 99%

Automatic Assessment of Lower-Limb Alignment from Computed Tomography

Kuiper

Seevinck

Viergever

et al. 2023

Journal of Bone and Joint Surgery

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Background: Preoperative planning of lower-limb realignment surgical procedures necessitates the quantification of alignment parameters by using landmarks placed on medical scans. Conventionally, alignment measurements are performed on 2-dimensional (2D) standing radiographs. To enable fast and accurate 3-dimensional (3D) planning of orthopaedic surgery, automatic calculation of the lower-limb alignment from 3D bone models is required. The goal of this study was to develop, validate, and apply a method that automatically quantifies the parameters defining lower-limb alignment from computed tomographic (CT) scans.Methods: CT scans of the lower extremities of 50 subjects were both manually and automatically segmented. Thirty-two manual landmarks were positioned twice on the bone segmentations to assess intraobserver reliability in a subset of 20 subjects. The landmarks were also positioned automatically using a shape-fitting algorithm. The landmarks were then used to calculate 25 angles describing the lower-limb alignment for all 50 subjects. Results:The mean absolute difference (and standard deviation) between repeat measurements using the manual method was 2.01 ± 1.64 mm for the landmark positions and 1.05°± 1.48°for the landmark angles, whereas the mean absolute difference between the manual and fully automatic methods was 2.17 ± 1.37 mm for the landmark positions and 1.10°± 1.16°for the landmark angles. The manual method required approximately 60 minutes of manual interaction, compared with 12 minutes of computation time for the fully automatic method. The intraclass correlation coefficient showed good to excellent reliability between the manual and automatic assessments for 23 of 25 angles, and the same was true for the intraobserver reliability in the manual method. The mean for the 50 subjects was within the expected range for 18 of the 25 automatically calculated angles. Conclusions:We developed a method that automatically calculated a comprehensive range of 25 measurements that defined lower-limb alignment in considerably less time, and with differences relative to the manual method that were comparable to the differences between repeated manual assessments. This method could thus be used as an efficient alternative to manual assessment of alignment.Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence. Surgical correction of a lower-limb malalignment typically consists of an osteotomy in the femur and/or tibia. For surgical planning, the malalignment is quantified using predefined landmarks and angles, such as the center points of the femoral head, knee, and ankle, which define the mechanical hip-knee-ankle (mHKA) angle. Paley 1 described these angles, and the methods to restore the alignment, for almost all types of malalignments.Conventionally, these angles are measured on 2-dimensional (2D) radiographs to define the malalignment in the frontal and sagittal planes. The introduction of 3-dimensional (3D) imaging and planning now enables mor...

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Influence of axial limb rotation on radiographic lower limb alignment: a systematic review

Cited by 29 publications

References 65 publications

Significant changes in lower limb alignment due to flexion and rotation—a systematic 3D simulation of radiographic measurements

Significant changes in lower limb alignment due to flexion and rotation—a systematic 3D simulation of radiographic measurements

Functional gait analysis reveals insufficient hindfoot compensation for varus and valgus osteoarthritis of the knee

Automatic Assessment of Lower-Limb Alignment from Computed Tomography

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