Lower Limb Torsion Research Articles

The Correlation between Lower Limb Torsion and Gait Angle: A Study on the Range of Motion of Hip and Knee Joints

The Correlation between Lower Limb Torsion and Gait Angle: A Study on the Range of Motion of Hip and Knee Joints

Interobserver reliability of biplanar radiography is unaffected by clinical factors relevant to individuals at risk of pathological lower limb torsion

BackgroundAssessments of lower limb torsion are ubiquitous in clinical gait analysis practice as pathologic lower limb rotational deformity may contribute to gait abnormalities, anterior knee pain, as well as other debilitating conditions. Understandably, the overall utility of any torsional assessment is dependent on the measurement method’s intrinsic accuracy, precision, and robustness to clinical interference factors. Recently, biplanar radiography (BPR) measurements of torsion have been shown to be both accurate and precise, but the robustness of BPR to potential interference factors is unknown. Research questionHow robust are BPR lower limb torsional assessments to six potential interference factors: amount of torsion, skeletal maturity, radiograph quality, prior osteotomy, presence of implants, and observer training background and experience? MethodsIn this retrospective cohort study, four observers of diverse backgrounds and experience generated digital 3D reconstructions of 44 lower limbs using BPR images obtained during standard of care visits (age range 7–35 years). From each reconstruction, four lower limb torsional parameters were computed: femoral torsion, femorotibial rotation, tibial torsion, and transmalleolar axis equivalent. The mean absolute deviation (MAD) of each torsional parameter – calculated across the four observers – was used as the measure of reliability and tested against all interference factors. ResultsResults demonstrated that the average MAD was 2.1 degrees for femoral torsion, 3.0 degrees for transmalleolar axis equivalent, 3.8 degrees for femorotibial rotation, and 4.7 degrees for tibial torsion. None of the six potential interference factors were found to systematically influence BPR reliability across all four torsional parameters. Of the factors found to statistically influence one or more torsional parameter, none affected MAD values to a clinically meaningful extent. SignificanceIn addition to being accurate and precise, BPR appears to be robust to several clinical factors relevant to children and young adults with or at risk for pathological lower limb torsion.

Artificial intelligence-based automatic assessment of lower limb torsion on MRI

Abnormal torsion of the lower limbs may adversely affect joint health. This study developed and validated a deep learning-based method for automatic measurement of femoral and tibial torsion on MRI. Axial T2-weighted sequences acquired of the hips, knees, and ankles of 93 patients (mean age, 13 ± 5 years; 52 males) were included and allocated to training (n = 60), validation (n = 9), and test sets (n = 24). A U-net convolutional neural network was trained to segment both femur and tibia, identify osseous anatomic landmarks, define pertinent reference lines, and quantify femoral and tibial torsion. Manual measurements by two radiologists provided the reference standard. Inter-reader comparisons were performed using repeated-measures ANOVA, Pearson’s r, and the intraclass correlation coefficient (ICC). Mean Sørensen-Dice coefficients for segmentation accuracy ranged between 0.89 and 0.93 and erroneous segmentations were scarce. Ranges of torsion as measured by both readers and the algorithm on the same axial image were 15.8°–18.0° (femur) and 33.9°–35.2° (tibia). Correlation coefficients (ranges, .968 ≤ r ≤ .984 [femur]; .867 ≤ r ≤ .904 [tibia]) and ICCs (ranges, .963 ≤ ICC ≤ .974 [femur]; .867 ≤ ICC ≤ .894 [tibia]) indicated excellent inter-reader agreement. Algorithm-based analysis was faster than manual analysis (7 vs 207 vs 230 s, p < .001). In conclusion, fully automatic measurement of torsional alignment is accurate, reliable, and sufficiently fast for clinical workflows.

Diagnostic accuracy of ultra-low-dose CT for torsion measurement of the lower limb

ObjectivesThe study aimed to investigate the diagnostic performance of simulated ultra-low-dose CT (ULD-CT) for torsion measurement of the lower limb.MethodsThirty retrospectively identified patients were included (32.3 ± 14.2 years; 14 women, 16 men). ULD-CT simulations were generated at dose levels of 100%, 10%, 5%, and 1% using two reconstruction methods: standard filtered back projection (FBP) and iterative reconstruction (ADMIRE). Two readers measured the lower limb torsion in all data sets. The readers also captured image noise in standardized anatomical landmarks. All data sets were evaluated regarding subjective diagnostic confidence (DC; 5-point Likert scale). Effective radiation dose of the original data sets and the simulated ULD-CT was compared.ResultsThere was no significant difference of measured lower limb torsion in any simulated dose level compared to the original data sets in both readers. Dose length product (DLP) of the original examinations was 402.1 ± 4.3 mGy cm, which resulted in an effective radiation dose of 4.00 ± 2.12 mSv. Calculated effective radiation dose in ULD-CT at 1% of the original dose was 0.04 mSv. Image noise increased significantly with dose reduction (p < 0.0001) and was dependent on the reconstructional method (p < 0.0001) with less noise using ADMIRE compared to FBP. Both readers rated DC at doses 100%, 10%, and 5% with 5.0/5: there were no ratings worse than 3/5 at 1% dose level.ConclusionsThe results suggest that radiation dose reduction down to 1% of original CT dose levels may be achieved in CT torsion measurements of the lower limb without compromising diagnostic accuracy.Key Points• Modern CT delivers exceptional high image quality in musculoskeletal imaging, especially for evaluation of osseous structures.• Usually, this high image quality is accompanied by significant radiation exposure to the patient and may not always be required for the intended purpose, e.g., pure delineation of cortical bone of the lower limb.• This study shows the tremendous prospects of radiation dose reduction without compromising diagnostic confidence in CT torsion measurement of the lower limb.

Healthy middle-aged Asian and Caucasian populations present with large intra- and inter-individual variations of lower limb torsion.

There is a lack of standardization in the measurement of lower limb torsional alignment. Normal values published in the literature are inconsistent. A 3D-CT-scan-based method was used in a healthy population to define the femoral neck version (FNV) and the tibial torsion (TT) and their relationship with demographic parameters. The study objectives were (1) to define normal values of lower limb torsional alignment, (2) to estimate inter- and intra-individual variations of torsional deformity of healthy individuals' lower limbs. The hypothesis was that FNV and TT values would be influenced by patient characteristics such as gender, age, and ethnicity, and would have low side-to-side asymmetry. Torsional landmarks of the lower limbs from 191 healthy subjects were automatically calculated with a 3D CT-scan-based program. The FNV was defined by the angle between the femoral neck axis and the femoral posterior condylar line. The TT angle was considered between the tibial plateau axis and the axis of the ankle. For the former, two alternatives were considered: the line connecting the more medial and lateral point of the medial and lateral plateau, respectively (method 1; TT1), or the line connecting the two more posterior points of the medial et lateral plateau (method 2; TT2). The ankle axis was defined as the line connecting the medial and lateral malleoli. These reference lines were automatically calculated. Age, gender, ethnic group, and BMI were recorded for every subject. A p value < 0.05 was considered as statistically significant. Overall, the mean FNV was 15.3 ± 9.5° and the mean TT was 31.6 ± 6.3°. Female hips were more anteverted than male hips. Caucasians had less anteverted hips than Asians, but more externally rotated tibias. Age and BMI were not correlated with any anatomical parameter. A substantial side-to-side asymmetry was found for FNV [absolute difference (AD) = 6.3°; percentage of asymmetry (%As) = 47%], TT1 (AD = 3°; %As = 12%), and TT2 (AD = 4.9°; %As = 9%) (p = 0.008). The findings showed that lower limb torsional parameters were highly variable from patient to patient and from one leg to the other for the same patient. The understanding of normal values concerning femoral version and external tibial torsion in the present healthy population will help surgeons to define pathological values of FNV and TT, as well as corrections to perform in case of torsional deformities. Level III.

Relationship between lower limb torsion and coronal morphologies of the femur and tibia in patients with medial knee osteoarthritis

BackgroundTo investigate the relationship between femoral or tibial torsion and hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), or mechanical medial proximal tibial angle (mMPTA) in patients with medial knee osteoarthritis (OA).MethodsA total of 75 knees were enrolled. Femoral and tibial torsions were measured by superimposing the axial planes of computed tomography images. The relationship between femoral or tibial torsion and HKA, mLDFA, or mMPTA on radiographs was examined.ResultsThe mean femoral torsion was 12.2 ± 8.5° internally; femoral internal and external torsions were observed in 70 and 5 knees, respectively. The mean tibial external torsion was 18.0 ± 7.4° externally; tibial external torsion was observed in all 75 knees. Femoral internal and tibial external torsions increased with lower mMPTA (r = 0.33, P = 0.003; r = − 0.32, P = 0.005, respectively) but were not related to HKA or mLDFA.ConclusionFemoral and tibial torsions were correlated with varus inclination of the proximal tibia in patients with medial knee OA.

A Novel Approach to Lower-limb Axial Alignment Analysis: A CT Study.

Purpose:To analyze the torsion of the lower extremities in a healthy cohort and to determine the contribution of different segments of the femur and tibia to the torsion of both bones.Methods:In this cross-sectional study, 32 patients with nonjoint or bone-related symptoms were analyzed by CT angiography. Lower-limb torsion, femoral torsion, proximal femoral torsion, femoral shaft torsion, distal femoral torsion, tibial torsion, proximal tibial torsion, and distal tibial torsion were measured.Results:The median total limb torsion was 25° external torsion, with the median femoral torsion being −9° and the median tibial torsion 30°. Both femoral metaphyses had internal torsion, with the internal torsion of the proximal metaphysis being approximately three times greater than that of the distal femoral metaphysis. The shaft was found to compensate with an external torsion of approximately two-thirds of the internal torsion of both femoral metaphyses. The proximal metaphysis of the tibia accounted for approximately one-third of the external torsion, with the segment from the distal to the tibial tubercle accounting for the remaining two-thirds of the tibial torsion.Conclusions:The diaphysis and distal metaphysis are the major contributors to external torsion of the tibia, whereas the proximal metaphysis is the major contributor to the internal torsion of the femur.

Patient absorbed dose comparison in CT and Stereoradiography (EOS) imaging during lower limb torsion evaluation using in-vivo and in-vitro dosimetry methods

Introduction: Accurate evaluation of femoral and tibial torsion is essential for children or adult with legs deformity, becuse incorrect legs morphogenesis can lead to pathological situation. CT scan is commonly used for the measurement of skeletal bone parameters. But, disability in imaging from standing and sitting posture and absorb dose of patients are deficits of this method. EOS method overcome this dificits. Likewise some paper have reported decrease of EOS dose rather than dose level in CT, this project aim to measure amount of dose reduction and to verify reduction of EOS dose level in compare to CT. Materials and Methods: For EOS and CT invitro dosimetry, a pencil ionization chamber was used. Computed tomography dose index volume (CTDIvol) was mesuered, using this dosimeter and standard tissue equivalent CT phantom. DLP of both imaging methods was compared for acquisition of adult hip. With radiothermoluminescent detectors (TLD) in vivo dosimetry enterans skin dose for 30 patients was measuered, which 15 of them were underwented CT scan and the other were underwented EOS imaging. Results: The reading of dosimeters level and therefor enterans skin doses, in EOS system was significantly lower than CT scan. Patient dose in AP, RT and LT fields of CT scan was respectively 24, 41.5 and 9 times more than EOS. Enterans skin dose in CT scan was 18 times more than EOS on average. Also, in invitro dosimetry CT scan dose was 47 times more than EOS dose. Conclusion: Elimination of scatter radiation and high quantum efficiency of detector lead to minimum dose for an optimum qulity scan with EOS system than CT scan. Stereoradiography imaging modality will impose less doses of CT scan imaging modality in similar imaging views from the lower limbs.

Anatomy of the proximal femur at the time of total hip arthroplasty is a matter of morphotype and etiology but not gender.

This study aimed to determine (1) whether: gender, morphotype, or etiology are correlated with the shape of the proximal femur in patients with advanced hip osteoarthritis and (2) is there any clinical predictive factors of potential abnormal anatomy of the hip at the time of total hip arthroplasty (THA)? We reviewed 689 European hips of patients who underwent THA for primary osteoarthritis (OA) or avascular necrosis (AVN), between 2000 and 2005. The patients were stratified according to their (1) Morphotype, (2) Gender, and (3) Etiology for undergoing THA. Two independent observers measured the following four anatomical parameters on preoperative CT-scans: neck shaft angle (NSA) and femoral neck version, femoral offset and lower-limb torsion. Our results showed that both morphotype and etiology, but not gender or body mass index, were correlated with femoral anatomical parameters. Two types of patients were identified as "at risk" for abnormal hip anatomy: (1) AVN-Endomorphic patients (2) OA-Ectomorphic patients. Etiology of the advanced hip osteoarthritis and patients' morphotype may predict the proximal femur anatomy at the time of THA.

EOS analysis of lower extremity segmental torsion in children and young adults

IntroductionLower limb torsion varies substantially among healthy children during growth. Values reported in the literature to date have been obtained using semi-quantitative clinical or 2D measurement methods. Quantitative 3D measurement would help determine the physiological range of lower limb torsion. Low-dose stereoradiography with 3D reconstruction provides a good alternative. Its use increases in pediatrics because of radiation minimization. Previous studies have shown accurate and reproducible results of lower limbs reconstruction in adults and children but the torsional parameters haven’t been measured yet. The present study reports the values of lower limb segmental torsion and its course during growth in a cohort of healthy children and young adults using the EOS low-dose biplanar X-ray. HypothesisEOS 3D reconstruction is an accurate and reproducible method to measure the torsional parameters in children. Materials and methodsFemoral torsion (FT) and tibial torsion (TT) were studied on 114 volunteers (228 lower limbs) from 6 to 30 years of age divided by age into 5 groups. The EOS™ acquisitions were obtained in subjects standing with their feet offset. ResultsMean FT decreased during growth, passing from 21.6° to 18°, whereas mean TT increased from 26.8° to 34.7°. There was a statistically significant difference between the 2 extreme age groups, but no difference was found between any other age groups. The ICC for intra-observer reproducibility was 0.96 and 0.95 for FT and TT for the first operator, and 0.79 and 0.83 for the second operator respectively. The ICC for inter-observer reproducibility was 0.84 and 0.82 respectively. DiscussionThe course of lower limb segmental torsion observed was consistent with literature reports based upon clinical and 2D measurements. 3D reconstruction of EOS low-dose biplanar imaging appears to be a safe and reliable tool for lower limbs measurements, especially for investigating lower limb segmental torsion in children and adults. Level of evidenceLevel IV.

Ionizing radiation doses during lower limb torsion and anteversion measurements by EOS stereoradiography and computed tomography

ObjectivesTo calculate and compare the doses of ionizing radiation delivered to the organs by computed tomography (CT) and stereoradiography (SR) during measurements of lower limb torsion and anteversion. Materials and methodsA Rando anthropomorphic phantom (Alderson RANDO phantom, Alderson Research Laboratories Inc., Stanford, Conn) was used for the dose measurements. The doses were delivered by a Somatom 16-slice CT-scanner (Siemens, Erlangen) and an EOS stereoradiography unit (EOS-Imaging, Paris) according to the manufacturers’ acquisition protocols. Doses to the surface and deeper layers were calculated with thermoluminiscent GR207P dosimeters. Dose uncertainties were evaluated and assessed at 6% at k=2 (that is, two standard deviations). ResultsThe absorbed doses for the principal organs assessed were as follows: for the ovaries, 0.1mGy to the right ovary and 0.5mGy to the left ovary with SR versus1.3mGy and 1.1mGy with CT, respectively; testes, 0.3mGy on the right and 0.4mGy on the left with SR versus 8.5mGy and 8.4mGy with CT; knees, 0.4mGy to the right knee and 0.8mGy to the left knee with SR versus 11mGy and 10.4mGy with CT; ankles, 0.5mGy to the right ankle and 0.8mGy to the left with SR versus 15mGy with CT. ConclusionThe SR system delivered substantially lower doses of ionizing radiation doses than CT to all the organs studied: CT doses were 4.1 times higher to the ovaries, 24 times higher for the testicles, and 13–30 times higher for the knees and ankles. The use of the SR system to study the torsion of lower limbs makes it possible to reduce the amount of medical irradiation that patients accumulate.

Measuring femoral and rotational alignment: EOS system versus computed tomography

Computed tomography (CT) is currently the reference standard for measuring femoral and tibial rotational alignment. The EOS System is a new biplanar low-dose radiographic device that allows 3-dimensional lower-limb modelling with automated measurements of femoral and tibial rotational alignment (torsion). Femoral and tibial torsion measurements provided by the EOS System are equivalent to those obtained using CT. In a retrospective analysis of 43 lower limbs in 30 patients, three senior radiologists measured femoral and tibial torsion on both CT and EOS images. Agreement between CT and EOS values was assessed by computing Pearson's correlation coefficient and interobserver reproducibility by computing the intraclass correlation coefficient (ICC). Femoral torsion was 13.4° by EOS vs. 13.7° by CT (P=0.5) and tibial torsion was 30.8° by EOS vs. 30.3° by CT (P=0.4). Strong associations were found between EOS and CT values for both femoral torsion (P=0.93) and tibial torsion (P=0.89). With EOS, the ICC was 0.93 for femoral torsion and 0.86 for tibial torsion; corresponding values with CT were 0.90 and 0.92. The EOS system is a valid alternative to CT for lower-limb torsion measurement. EOS imaging allows a comprehensive evaluation in all three planes while substantially decreasing patient radiation exposure. Level III, case-control.

Does Lower Limb Torsion Matter?

Does Lower Limb Torsion Matter?

Reliability of the assessment of lower limb torsion using computed tomography: analysis of five different techniques

Various methods have been described to define the femoral neck and distal tibial axes based on a single CT image. The most popular are the Hernandez and Weiner methods for defining the femoral neck axis and the Jend, Ulm, and bimalleolar methods for defining the distal tibial axis. The purpose of this study was to calculate the intra- and interobserver reliability of the above methods and to determine intermethod differences. Three physicians separately measured the rotational profile of 44 patients using CT examinations on two different occasions. The average age of patients was 36.3 ± 14.4 years, and there were 25 male and 19 female patients. After completing the first two sessions of measurements, one observer chose certain cuts at the levels of the femoral neck, femoral condylar area, tibial plateau, and distal tibia. The three physicians then repeated all measurements using these CT cuts. The greatest interclass correlation coefficients were achieved with the Hernandez (0.99 intra- and 0.93 interobserver correlations) and bimalleolar methods (0.99 intra- and 0.92 interobserver correlations) for measuring the femoral neck and distal tibia axes, respectively. A statistically significant decrease in the interobserver median absolute differences could be achieved through the use of predefined CT scans only for measurements of the femoral condylar axis and the distal tibial axis using the Ulm method. The bimalleolar axis method underestimated the tibial torsion angle by an average of 4.8° and 13° compared to the Ulm and Jend techniques, respectively. The methods with the greatest inter- and intraobserver reliabilities were the Hernandez and bimalleolar methods for measuring femoral anteversion and tibial torsion, respectively. The high intermethod differences make it difficult to compare measurements made with different methods.

Torsion deformity and joint loading for medial knee osteoarthritis

PurposeThe consequences of lower limb torsion deformity on knee loading in knee osteoarthritis are poorly understood. The purpose of this study was to quantify the associations between the mechanical axis, tibial torsion and knee loading in subjects with medial knee OA and in controls. MethodsTwenty-four subjects: end-staged medial knee osteoarthritis (OA) with apparent torsion deformity (TKO, n=6) and without torsion deformity (KOA, n=8) and controls (CON, n=10) were imaged using long standing lower extremity (LSLE) radiographs and computed tomography (CT). Medial knee loading was assessed using the internal knee varus moment determined by gait analysis. The LSLE mechanical axis, CT tibial torsion and the foot progression angle were used to predict medial knee loading. ResultsThe TKOs had significantly greater mechanical axis varus and knee varus moment compared to KOAs and CONs. The regression model predicting medial knee loading using the mechanical axis (β=0.898), tibial torsion (β=0.264) and foot progression angle (β=−0.369) showed a goodness of fit of 0.774. ConclusionsMedial knee loading was predicted by the mechanical axis and the foot progression angle. Future longitudinal studies are needed to assess the role of tibial intorsion during disease progression and following total knee replacement surgery.

The neck–malleolar angle: an alternative method for measuring total lower limb torsion that considers the knee joint rotation angle

A greater understanding of the lower limb geometry is necessary for the correction of lower limb torsional deformities. The purpose of our study was to measure the normal values of knee torsion using CT and to introduce the neck-malleolar angle as an alternative for measuring lower limb torsion. We studied 77 consecutive CT studies performed from 2007 to 2009 in our clinic. In 67 cases, there was evidence of old trauma or surgical intervention to one limb, whereas the contralateral limb was healthy. The remaining 10 patients had no history of trauma or surgical intervention and were available for paired analysis in order to find the normal intraindividual variability. The whole limb, femoral and tibial torsion were measured according to the "Ulm method". Finally, the knee joint rotational angle and the neck-malleolar angle (the angle between the femoral neck axis and the bimalleolar axis) were measured. The average knee joint rotation angle was 2.4 ± 6.4° while the neck-malleolar angle was 13.2 ± 10.2°. Right to left side differences in healthy paired limbs for total limb rotation, knee joint rotation and the neck-malleolar angle were 6.1 ± 4.1°, 3.9 ± 2.8° and 7.5 ± 4.3° respectively. The mean absolute rotational differences between injured and healthy limbs was 14.5 ± 10.1°, whereas the mean absolute neck-malleolar differences amounted to 12.5 ± 9.9° (p = 0.013) indicating that the knee compensates for torsional asymmetries. The neck-malleolar angle takes into consideration the buffering effects of the knee joint in the transverse plane and contributes valuable additional information. Further studies including the long-term results of patients with torsional errors are important.

Some words about lower limb torsion and rotation problems

The notions of torsion and rotation of the lower limb, loading and the progression of segmentary torsions are defined. It is shown that, while proximal dysmorphisms (anteversion of the hip) may lead to distal dysmorphisms, the latter, such as cavovalgus foot, may be implicated in the progression of dysmorphisms of both the knee (femoropatellar impingement syndromes) and the hip (residual anteversion).

Effects of Lower Limb Torsion on Ankle Kinematic Data During Gait Analysis

VICON Clinical Manager software is widely used for gait analysis and has four methods for computing ankle plantarflexion–dorsiflexion motion and transverse plane ankle rotation profiles. The authors evaluated 14 subjects with a diagnosis of spastic cerebral palsy and tibial torsion ranging from 39° internal torsion to 90° external torsion, using the four different processing methods. It was found that clinically measured tibial torsion >20° external or >15° internal led to significant differences in the calculated ankle plantarflexion–dorsiflexion and transverse plane ankle rotation measurements between the four methods. Pearson correlations indicated that these differences increased with increasing external or internal tibial torsion. The variability was enough to affect conclusions of published articles and clinical decision making.

Effects of lower limb torsion on ankle kinematic data during gait analysis.

VICON Clinical Manager software is widely used for gait analysis and has four methods for computing ankle plantarflexion-dorsiflexion motion and transverse plane ankle rotation profiles. The authors evaluated 14 subjects with a diagnosis of spastic cerebral palsy and tibial torsion ranging from 39 degrees internal torsion to 90 degrees external torsion, using the four different processing methods. It was found that clinically measured tibial torsion >20 degrees external or >15 degrees internal led to significant differences in the calculated ankle plantarflexion-dorsiflexion and transverse plane ankle rotation measurements between the four methods. Pearson correlations indicated that these differences increased with increasing external or internal tibial torsion. The variability was enough to affect conclusions of published articles and clinical decision making.

Gamma knife radiosurgery for torsion spasm

✓ The authors report on two patients who underwent radiosurgery for torsion spasm and evaluate the efficiency of gamma knife radiosurgery (GKS) as an alternative treatment. The first patient was a 33-year-old woman with severe right-sided lower-limb torsion dystonia. The second patient was a 20-year-old man with right-sided upper-limb torsion dystonia. The target was located at the anterior portion of the ventrolateral nucleus. The maximum doses were 150 Gy and 145 Gy, respectively. Double isocenters with a 4-mm collimator were used. Follow up lasted for 18 months and 8 months, respectively. Both patients had excellent clinical improvement 2 to 3 months after GKS, respectively. The authors believe that GKS may be a safe and efficient treatment for torsion spasm.