Publications by authors named "Seungbum Koo"

48 Publications

Relationship between radiographic measurements and knee adduction moment using 3D gait analysis.

Gait Posture 2021 Sep 1;90:179-184. Epub 2021 Sep 1.

Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam-si, South Korea; Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul, South Korea.

Background: Radiographic factors estimate the state of the static knee joint, and it is questionable how well these parameters reflect the dynamic knee condition. The external knee adduction moment (KAM) during gait is known to be a kinetic variable contributing to osteoarthritis progression. This study aims to investigate the effects of static radiographic parameters on the dynamic KAM during gait.

Methods: Overall, 123 patients (mean age, 65.7 years; standard deviation, 8.1 years; 34 men and 89 women) were included. Seven radiographic parameters including the mechanical tibiofemoral angle (mTFA), Kellgren-Lawrence grade, and ankle joint line orientation (AJLO) were measured on radiographs, and the maximum KAM and KAM-time integral in the stance phase were obtained using three-dimensional gait analysis. The correlation and multiple regression analyses were performed for identifying significant radiographic measurements associated with the KAM.

Results: Most of the radiographic measurements correlated with the maximum KAM and KAM-time integral. As a result of multiple regression analysis, the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as significant factors associated with the KAM-time integral (R = 0.450); the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as a significant factor associated with the maximum KAM (R = 0.352) in multiple regression analysis. The discriminant validity of KAM was highest at varus 5.7 degree of the mTFA and 7.5 degree of the AJLO.

Significance: The mTFA and AJLO were significantly associated with the KAM. However, to be used as a surgical indication for corrective osteotomy, a longitudinal study is needed to validate whether the mTFA and AJLO values directly cause osteoarthritis progression as we have suggested.

Level Of Evidence: III.
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http://dx.doi.org/10.1016/j.gaitpost.2021.08.025DOI Listing
September 2021

Kinematic instability in the joints of flatfoot subjects during walking: A biplanar fluoroscopic study.

J Biomech 2021 Aug 10;127:110681. Epub 2021 Aug 10.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea. Electronic address:

Abnormal foot kinematics is observed in flatfoot subjects with postural foot deformity. We aimed to investigate joint instability in flatfoot subjects by analyzing the abnormal rotational position and speed of their joints while walking. Five flatfoot subjects participated in our study. Three-dimensional motions of the tibia, talus, calcaneus, navicular, and cuboid were obtained during walking using the biplanar fluoroscopic motion analyses. An anatomical coordinate system was established for each bone. The rotations and ranges of motion (ROMs) of the joints from heel-strike to toe-off were quantified. The relative movements on the articular surfaces were quantified by surface relative velocity vector analysis. The data from flat foot subjects were compared with the data from normal foot subjects in previous studies. The average relative speed on the articular surface of the tibiotalar, subtalar, and calcaneocuboid joints for the flatfoot subjects was significantly higher (p < 0.05) than that for the normal foot subjects. The flatfoot subjects exhibited increased movements toward plantar flexion in the tibiotalar joint, and eversion and external rotations in the talonavicular joint during the stance phase, compared to the normal subjects (p < 0.01). Furthermore, the flatfoot subjects had a significantly larger ROM along with the inversion/eversion rotations (5.6 ± 1.8° vs. 10.7 ± 4.0°) and internal/external rotations (7.1 ± 1.5° vs. 10.5 ± 3.5°) in the tibiotalar joint. The flatfoot subjects demonstrated abnormal kinematics and larger joint movements in multiple joints during the mid-stance and terminal stance phases of walking. This demonstrates their high instability levels.
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http://dx.doi.org/10.1016/j.jbiomech.2021.110681DOI Listing
August 2021

Anomalous gait feature classification from 3-D motion capture data.

IEEE J Biomed Health Inform 2021 Aug 4;PP. Epub 2021 Aug 4.

The gait kinematics of an individual is affected by various factors, including age, anthropometry, gender, and disease. Detecting anomalous gait features aids in the diagnosis and treatment of gait-related diseases. The objective of this study was to develop a machine learning method for automatically classifying five anomalous gait features, i.e., toe-out, genu varum, pes planus, hindfoot valgus, and forward head posture features, from three-dimensional data on gait kinematics. Gait data and gait feature labels of 488 subjects were acquired. The orientations of the human body segments during a gait cycle were mapped to a low-dimensional latent gait vector using a variational autoencoder. A two-layer neural network was trained to classify five gait features using logistic regression and calculate an anomalous gait feature vector (AGFV). The proposed network showed balanced accuracies of 82.8% for a toe-out, 85.9% for hindfoot valgus, 80.2% for pes planus, 73.2% for genu varum, and 92.9% for forward head posture when the AGFV was rounded to the nearest zero or 1. Multiple anomalous gait features were detectable using the proposed method, which has a practical advantage over current gait indices, including the gait deviation index with a single value. The overall results confirmed the feasibility of using the proposed method for screening subjects with anomalous gait features using three-dimensional motion capture data.
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http://dx.doi.org/10.1109/JBHI.2021.3101549DOI Listing
August 2021

Uniqueness of gait kinematics in a cohort study.

Sci Rep 2021 Jul 27;11(1):15248. Epub 2021 Jul 27.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.

Gait, the style of human walking, has been studied as a behavioral characteristic of an individual. Several studies have utilized gait to identify individuals with the aid of machine learning and computer vision techniques. However, there is a lack of studies on the nature of gait, such as the identification power or the uniqueness. This study aims to quantify the uniqueness of gait in a cohort. Three-dimensional full-body joint kinematics were obtained during normal walking trials from 488 subjects using a motion capture system. The joint angles of the gait cycle were converted into gait vectors. Four gait vectors were obtained from each subject, and all the gait vectors were pooled together. Two gait vectors were randomly selected from the pool and tested if they could be accurately classified if they were from the same person or not. The gait from the cohort was classified with an accuracy of 99.71% using the support vector machine with a radial basis function kernel as a classifier. Gait of a person is as unique as his/her facial motion and finger impedance, but not as unique as fingerprints.
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http://dx.doi.org/10.1038/s41598-021-94815-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8316524PMC
July 2021

Intrasubject Radiographic Progression of Hallux Valgus Deformity in Patients With and Without Metatarsus Adductus: Bilateral Asymmetric Hallux Valgus Deformity.

J Foot Ankle Surg 2021 Jun 11. Epub 2021 Jun 11.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejon, Korea. Electronic address:

This study was to analyze intrasubject radiographic progression of the hallux valgus deformity by comparing the mildly and severely affected sides in patients with bilateral asymmetric hallux valgus in the whole group as well as the metatarsus adductus and the nonmetatarsus adductus subgroups. A total of 186 patients with bilateral asymmetrical hallux valgus deformity with a difference of 5° or greater in the hallux valgus angle were included, and 11 radiographic measurements were analyzed. The radiographic differences between the mildly and severely affected sides were compared. Correlation between the changes in the hallux valgus angle and those in other measurements was analyzed, and multiple regression analyses were performed. The anteroposterior talo-second metatarsal angle showed no significant difference between the mildly and severely affected sides. Changes in the intermetatarsal angle and sesamoid rotation angle were significantly associated with the progression of hallux valgus angle in the whole group as well as the nonmetatarsus adductus subgroup. Change in the intermetatarsal angle (p = .006) was the significant factor associated with the progression of hallux valgus angle in the metatarsus adductus subgroup. The anteroposterior talo-second metatarsal angle might be useful in evaluating the overall foot shape in the hallux valgus deformity. Progression of the hallux valgus deformity might be pathophysiologically different between those with and without metatarsus adductus.
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http://dx.doi.org/10.1053/j.jfas.2020.05.025DOI Listing
June 2021

Application of Principal Component Analysis Approach to Predict Shear Strength of Reinforced Concrete Beams with Stirrups.

Materials (Basel) 2021 Jun 22;14(13). Epub 2021 Jun 22.

Department of Architectural Engineering, Inha University, Incheon 22212, Korea.

The reinforced concrete (RC) member's shear strength estimation has been experimentally studied in most cases due to its nonlinear behavior. Many empirical equations have been derived from the experimental data; however, even those adopted in the construction codes do not thoroughly and accurately describe their shear behavior. Theoretically explained equations, on the other hand, are aligned with the experiment; however, they are complicated to use in practice. As shear behavior research is data-driven, the machine learning technique is applicable. Herein, an artificial neural network (ANN) algorithm is trained with 776 experiment results collected from available publications. The raw data is preprocessed by principal component analysis (PCA) before the application of the ANN technique. The predictions of the trained algorithm using ANN with PCA are compared to those of formulae adopted in a few existing building codes. Finally, a parametric study is conducted, and the significance of each variable to the strength of RC members is analyzed.
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http://dx.doi.org/10.3390/ma14133471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8269491PMC
June 2021

Relationship between ankle varus moment during gait and radiographic measurements in patients with medial ankle osteoarthritis.

PLoS One 2021 24;16(6):e0253570. Epub 2021 Jun 24.

Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam-si, South Korea.

Background: Kinetic data obtained during gait can be used to clarify the biomechanical pathogenesis of osteoarthritis of the lower extremity. This study aimed to investigate the difference in ankle varus moment between the varus angulation and medial translation types of medial ankle osteoarthritis, and to identify the radiographic measurements associated with ankle varus moment.

Methods: Twenty-four consecutive patients [mean age 65.8 (SD) 8.0 years; 9 men and 15 women] with medial ankle osteoarthritis were included. Fourteen and 10 patients had the varus angulation (tibiotalar tilt angle≥3 degrees) and medial translation (tibiotalar tilt angle<3 degrees) types, respectively. All patients underwent three-dimensional gait analysis, and the maximum varus moment of the ankle was recorded. Radiographic measurement included tibial plafond inclination, tibiotalar tilt angle, talar dome inclination, and lateral talo-first metatarsal angle. Comparison between the two types of medial ankle osteoarthritis and the relationship between the maximum ankle varus moment and radiographic measurements were analyzed.

Results: The mean tibial plafond inclination, tibiotalar tilt angle, talar dome inclination, lateral talo-first metatarsal angle, and maximum ankle varus moment were 6.4 degrees (SD 3.3 degrees), 5.0 degrees (SD 4.6 degrees), 11.4 degrees (SD 5.2 degrees), -6.5 degrees (SD 11.7 degrees), and 0.185 (SD 0.082) Nm/kg, respectively. The varus angulation type showed a greater maximum ankle varus moment than the medial translation type (p = .005). The lateral talo-first metatarsal angle was significantly associated with the maximum ankle varus moment (p = .041) in the multiple regression analysis.

Conclusion: The varus angulation type of medial ankle osteoarthritis is considered to be more imbalanced biomechanically than the medial displacement type. The lateral talo-first metatarsal angle, being significantly associated with the ankle varus moment, should be considered for correction during motion-preserving surgeries for medial ankle osteoarthritis to restore the biomechanical balance of the ankle.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0253570PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8224910PMC
June 2021

Predicting Long-Term Deformation of Soundproofing Resilient Materials Subjected to Compressive Loading: Machine Learning Approach.

Materials (Basel) 2020 Sep 17;13(18). Epub 2020 Sep 17.

Korea Institute of Civil Engineering and Building Technology, Ilsan 10223, Korea.

Soundproofing materials are widely used within structural components of multi-dwelling residential buildings to alleviate neighborhood noise problems. One of the critical mechanical properties for the soundproofing materials to ensure its appropriate structural and soundproofing performance is the long-term compressive deformation under the service loading conditions. The test method in the current test specifications only evaluates resilient materials for a limited period (90-day). It then extrapolates the test results using a polynomial function to predict the long-term compressive deformation. However, the extrapolation is universally applied to materials without considering the level of loads; thus, the calculated deformation may not accurately represent the actual compressive deformation of the materials. In this regard, long-term compressive deformation tests were performed on the selected soundproofing resilient materials (i.e., polystyrene, polyethylene, and ethylene-vinyl acetate). Four levels of loads were chosen to apply compressive loads up to 350 to 500 days continuously, and the deformations of the test specimens were periodically monitored. Then, three machine learning algorithms were used to predict long-term compressive deformations. The predictions based on machine learning and ISO 20392 method are compared with experimental test results, and the accuracy of machine learning algorithms and ISO 20392 method are discussed.
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http://dx.doi.org/10.3390/ma13184133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7560409PMC
September 2020

Posterior Tibial Tendon Integrity Can Be Screened With Plain Anteroposterior Foot Radiography.

Orthopedics 2020 Nov 3;43(6):e503-e507. Epub 2020 Sep 3.

Posterior tibial tendon integrity is an important consideration when treating adult-acquired flatfoot caused by posterior tibial tendon dysfunction. The condition of this tendon traditionally has been evaluated with ultrasonography or magnetic resonance imaging, but recent advances in radiography have increased the resolution of radiographic soft tissue images. The authors examined whether the posterior tibial tendon could be screened with anteroposterior foot radiographs, based on interobserver agreement and accuracy. The authors retrospectively evaluated consecutive patients who underwent weight-bearing foot radiography and ultrasonography based on suspicion of posterior tibial tendinopathy. The integrity of the posterior tibial tendon was evaluated by 2 orthopedic surgeons with foot radiographs and scored as normal or abnormal. The authors evaluated interobserver agreement and compared the findings of ultrasonography and radiography to evaluate diagnostic accuracy. The study included 21 patients with a mean age of 51.5±15.7 years. Ultrasonography showed that 4 patients had normal tendon integrity, 6 patients had tenosynovitis and no tendinopathy, 8 patients had tendinopathy and tendon continuity, and 3 patients had loss of tendon continuity. The surgeons provided consistent radiographic findings for 81.0% of patients (17 of 21). On the basis of the ultrasonographic findings, the surgeons' accuracy was 76.2% (16 of 21) and 61.9% (13 of 21). The results indicate that weight-bearing anteroposterior foot radiography can be used to evaluate posterior tibial tendon integrity, which may allow orthopedic surgeons to predict the prognosis of patients with posterior tibial tendon dysfunction, determine the extent of surgical treatment, and evaluate tendon integrity postoperatively. [Orthopedics. 2020;43(6):e503-e507.].
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http://dx.doi.org/10.3928/01477447-20200827-04DOI Listing
November 2020

Increase of stiffness in plantar fat tissue in diabetic patients.

J Biomech 2020 06 22;107:109857. Epub 2020 May 22.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea. Electronic address:

Plantar soft tissue stiffening in diabetes leads to a risk of developing ulcers. There are relatively few studies providing methods for quantifying the mechanical properties of skin and fat in the plantar tissue of diabetic patients. Previous studies used linear or non-linear single layer deformable models or linear multi-layer models. This study aimed to investigate the mechanical properties of plantar soft tissue using multi-layer, non-linear models to estimate more accurate mechanical properties in the plantar tissues of diabetic patients. Ten healthy young (HY) subjects, ten healthy old (HO) subjects, and ten old diabetic patients (DB) volunteered for the study. Indentation tests were performed at two sites in the heel. The subjects underwent computed tomography (CT) to measure the respective thicknesses of the skin and fat at the indentation sites. Subject-specific finite element models were created to estimate the parameters of the first-order Ogden forms of the skin and fat. The initial shear modulus for the fat layer μ in DB, HO, and HY were 4.68 MPa (±0.87), 2.71 MPa (±1.25), and 2.27 MPa (±0.87), respectively. The initial shear modulus for the skin layer (μ) in DB, HO, and HY were 5.86 MPa (±2.51), 7.05 MPa (±1.94), and 14.58 MPa (±1.98), respectively. The DB had stiffer fat tissue than the normal subjects in the same age group but had the same soft skin. These aspects can cause different mechanical stress conditions in a diabetic foot than in a normal foot under the same mechanical loading, making the diabetic foot vulnerable to the initiation of mechanical breakdowns such as ulcers.
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http://dx.doi.org/10.1016/j.jbiomech.2020.109857DOI Listing
June 2020

Analysis of three-dimensional computed tomography talar morphology in relation to pediatric pes planovalgus deformity.

J Pediatr Orthop B 2019 Nov;28(6):591-597

Department of Orthopedic Surgery, Soon Chun Hyang University Hospital, Cheonan, South Korea.

Intraosseous alignment of the tarsal bone has not been investigated in relation to various foot deformities. This study aimed to investigate three-dimensional computed tomography (3D CT) talar morphology in children with idiopathic and neuromuscular pes planovalgus. Eleven children [nine boys, two girls; mean (SD) age: 10.5 (2.8) years] with idiopathic pes planovalgus and 15 children [three boys, 12 girls; mean (SD) age: 10.8 (3.4) years] with neuromuscular pes planovalgus were included. All patients underwent 3D CT and weight-bearing anteroposterior, lateral, and axial radiography. Demographic data and talar 3D CT and radiographic measurements were compared between both groups. The correlation between the measurements was also analyzed. The neuromuscular group showed significantly more severe deformity than the idiopathic group in the radiographic and 3D sagittal talus measurements. The 3D coronal talus measurement showed a significant negative correlation with the axial hindfoot alignment in the idiopathic group while the 3D transverse talus measurement was significantly correlated with the lateral talocalcaneal angle in the neuromuscular group. 3D intraosseous alignment of the talus is correlated with pes planus deformity. Longitudinal and biomechanical studies including a control group are necessary to elucidate the role of 3D talar morphology on a dynamic imbalance in pes planovalgus.
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http://dx.doi.org/10.1097/BPB.0000000000000597DOI Listing
November 2019

Inverse Relationship Between Radiographic Lateral Ankle Instability and Osteochondral Lesions of the Talus in Patients With Ankle Inversion Injuries.

Foot Ankle Int 2019 Dec 27;40(12):1368-1374. Epub 2019 Aug 27.

Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.

Background: Insufficient or excessive bony constraint surrounding the talus might contribute to the occurrence of ligamentous injury or bone contusion, respectively, at the time of ankle inversion injuries. This study aimed to investigate the relationship between radiographic lateral ankle instability and osteochondral lesions of the talus (OLT) following ankle inversion injuries.

Methods: A total of 195 patients (113 men and 83 women; mean age, 38.7 years) with a history of ankle inversion injuries were included in this study. All patients underwent ankle magnetic resonance imaging (MRI) and stress radiography. The tibiotalar tilt angle on varus stress radiograph, anterior translation of the talus on anterior-drawer lateral radiographs, bimalleolar tilt angle, and fibular position were radiographically determined. The radiographic lateral ankle instability was defined as tibiotalar tilt angle ≥10 degrees, and the presence of OLT was confirmed on MR images. The relationship between the radiographic lateral ankle instability and the presence of OLT was statistically analyzed.

Results: The presence of radiographic lateral ankle instability (tibiotalar tilt angle ≥10 degrees) showed an inverse relationship with that of OLT in the chi-squared test ( = .003). An increased tibiotalar tilt angle was associated with lower incidence of OLT ( = .011) in the multiple regression analysis, and the presence of OLT was associated with a decreased tibiotalar tilt angle ( = .016) in the binary logistic regression analysis.

Conclusions: This study showed an inverse relationship between lateral ankle instability and the development of OLT following ankle inversion injury. The role of bony constraint in the development of sports injuries in the ankle should be considered with these injuries.

Level Of Evidence: Level III, diagnostic, comparative study.
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http://dx.doi.org/10.1177/1071100719868476DOI Listing
December 2019

The increase of joint contact forces in foot joints with simulated subtalar fusion in healthy subjects.

Gait Posture 2019 10 9;74:27-32. Epub 2019 Aug 9.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea. Electronic address:

Background: Subtalar fusion usually leads to a satisfactory clinical outcome by eliminating the motion of the subtalar joint but can cause an aggravation of osteoarthritis after the subtalar fusion. Previous studies have investigated the effect of subtalar fusion in static testing using cadaver limbs, but there was no evidence of an aggravation of osteoarthritis.

Research Question: The objective was to investigate the differences in foot joint kinematics and kinetics during a standing pose and walking with and without subtalar fusion, using a musculoskeletal simulation.

Methods: Full-body joint kinematics, ground reaction force, and foot pressure of the healthy subjects were recorded during walking using an optical motion capture system. The models with and without subtalar fusion were constructed using the AnyBody Modeling System (AnyBody Technology, Aalborg, Denmark). The range of motion and contact forces in the individual foot joints with and without simulated subtalar fusion in healthy subjects were estimated using computational simulation and compared using the Wilcoxon signed-rank test. The change of motion in the Chopart's joint was observed.

Results: Normalized to the subject's body weight (BW), the average maximum contact forces in the tibiotalar and Lisfranc joints during walking were significantly increased by 2.6 and 0.9 BW with the simulated subtalar joint fusion, respectively. The simulated subtalar joint fusion increased joint contact forces significantly during walking, which can increase the risks of secondary arthritis in the adjacent joints.

Significance: The subtalar joint fusion increased the joint contact forces in adjacent joints during walking implying that the fusion can increase the risk of secondary injuries in adjacent joints in the foot.
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http://dx.doi.org/10.1016/j.gaitpost.2019.07.376DOI Listing
October 2019

Skeletal kinematics of the midtarsal joint during walking: Midtarsal joint locking revisited.

J Biomech 2019 Oct 8;95:109287. Epub 2019 Aug 8.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea. Electronic address:

The kinematics of the human foot complex have been investigated to understand the weight bearing mechanism of the foot. This study aims to investigate midtarsal joint locking during walking by noninvasively measuring the movements of foot bones using a high-speed bi-planar fluoroscopic system. Eighteen healthy subjects volunteered for the study; the subjects underwent computed tomography imaging and bi-planar radiographs of the foot in order to measure the three-dimensional (3D) midtarsal joint kinematics using a 2D-to-3D registration method and anatomical coordinate system in each bone. The relative movements on bone surfaces were also calculated in the talonavicular and calcaneocuboid joints and quantified as surface relative velocity vectors on articular surfaces to understand the kinematic interactions in the midtarsal joint. The midtarsal joint performed a coupled motion in the early stance to pronate the foot to extreme pose in the range of motion during walking and maintained this pose during the mid-stance. In the terminal stance, the talonavicular joint performed plantar-flexion, inversion, and internal rotation while the calcaneocuboid joint performed mainly inversion. The midtarsal joint moved towards an extreme supinated pose, rather than a minimum motion in the terminal stance. The study provides a new perspective to understand the kinematics and kinetics of the movement of foot bones and so-called midtarsal joint locking, during walking. The midtarsal joint continuously moved towards extreme poses together with the activation of muscle forces, which would support the foot for more effective force transfer during push-off in the terminal stance.
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http://dx.doi.org/10.1016/j.jbiomech.2019.07.031DOI Listing
October 2019

Effects of walking speed and slope on pedobarographic findings in young healthy adults.

PLoS One 2019 24;14(7):e0220073. Epub 2019 Jul 24.

Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea.

Background: This study aimed to investigate the effects of walking speed and slope on foot pressure changes in young healthy adults.

Methods: Twenty young healthy adults (mean age 22.4 years, SD 1.2 years; 10 male and 10 female) participated in the study. Dynamic pedobarographic data during treadmill walking were obtained for combinations of three different walking speeds (3.2 km/hr, 4.3 km/hr, and 5.4 km/hr) and 5 different slopes (downhill 8 degrees, downhill 4 degrees, ground walking (0 degree), uphill 4 degrees, and uphill 8 degrees). Pedobarographic data such as the peak pressure and pressure-time integral were measured on five plantar segments: medial forefoot (MFF), lateral forefoot (LFF), medial midfoot (MMF), lateral midfoot (LMF), and heel. Maximum ankle dorsiflexion was also recorded using the Plug in Gait marker set.

Results: All participants maintained heel-toe gait in all walking conditions. The peak pressure on the MFF during downhill slope walking was lower than that during ground and uphill walking, whereas the peak pressure on the MFF during uphill slope walking was similar to that during ground walking at each walking speed. The peak pressures on the heel were similar for different walking slopes at each walking speed. The peak pressures on the MFF and heel increased with an increase in walking speed. The pressure-time integral of the MFF did not show significant changes at different walking speeds and slopes. The pressure-time integral of the heel increased with an increase in walking slope and decrease in walking speed.

Conclusions: Different walking speeds and slopes affected the pedobarographic characteristics of young healthy adults. Downhill walking with slower speed appeared to be beneficial to reduce or optimize MFF pressures, while downhill walking at a comfortable speed would be helpful to reduce or optimize heel pressures. The findings of this study have clinical implications in recommending activities to patients with foot pressure-related symptoms and disorders.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220073PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6656354PMC
February 2020

Dynamic First Tarsometatarsal Instability During Gait Evaluated by Pedobarographic Examination in Patients With Hallux Valgus.

Foot Ankle Int 2019 Sep 19;40(9):1104-1109. Epub 2019 Jun 19.

1 Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea.

Background: This study aimed to investigate the pedobarographic characteristics of tarsometatarsal instability and to identify factors associated with pedobarographic first tarsometatarsal instability in patients with hallux valgus.

Methods: Fifty-seven patients (mean age, 59.7 years; standard deviation, 11.4 years; 6 men and 51 women) with a hallux valgus angle (HVA) greater than 15 degrees were included. All patients underwent a pedobarographic examination along with weightbearing anteroposterior (AP) and lateral foot radiography. Radiographic measurements were compared between the 2 groups with and without pedobarographic first tarsometatarsal instability. The association between the radiographic and pedobarographic parameters of the first tarsometatarsal instability was analyzed using the chi-square test. Binary logistic regression analysis was performed to identify significant factors affecting pedobarographic first tarsometatarsal instability.

Results: The HVA ( < .001), intermetatarsal angle ( = .001), and AP talo-first metatarsal angle were significantly different between the pedobarographically stable and unstable tarsometatarsal groups. There was no significant association between radiographic and pedobarographic instability of the first tarsometatarsal joint ( = .924). The HVA was found to be the only significant factor affecting pedobarographic tarsometatarsal joint instability ( = .001).

Conclusion: The pedobarographic examination has possible clinical utility in evaluating first tarsometatarsal joint instability in patients with hallux valgus. Patients with a greater HVA should be assessed for the presence of first tarsometatarsal instability, and the necessity of the Lapidus procedure should be considered.

Level Of Evidence: Level III, comparative study.
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http://dx.doi.org/10.1177/1071100719850802DOI Listing
September 2019

Resolution improving filter for time-reversal (TR) with a switching TR mirror in a halfspace.

J Acoust Soc Am 2019 04;145(4):2328

Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.

This paper addresses the issue of using a switching time-reversal (TR) mirror for wave energy focusing to subsurface targets. The motivation stems from applications in geophysics, hydro-geology, environmental engineering, and even in therapeutic medicine. Using TR concepts, wave-focusing is straightforward and efficient, but only under ideal conditions that are, typically, unattainable in practice. The unboundedness of the subsurface that hosts the target, the TR mirror's limited aperture, and, worse, the practical need for a switching TR mirror, where recorded Dirichlet data are time-reversed as Neumann data (switching mirror), all contribute to the deterioration of the focusing resolution at the target. Herein, the development of a data filter is discussed, which is shown to be capable of overcoming the switching mirror's shortcoming, leading to improved focusing resolution. The filter's effect is demonstrated with numerical examples.
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http://dx.doi.org/10.1121/1.5097674DOI Listing
April 2019

Three-dimensional kinematic coupling in the knee during normal walking.

J Biomech Eng 2019 Apr 24. Epub 2019 Apr 24.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.

Accurate joint kinematics play an important role in estimating joint kinetics in musculoskeletal simulations. Bi-planar fluoroscopic (BPF) systems have been introduced to measure skeletal kinematics with six degrees of freedom. The purpose of this study was to model knee kinematic coupling using knee kinematics during walking, as measured by the BPF system. Seven healthy individuals (mean age, 23±2 years) performed treadmill walking trials at 1.2 m/s. Knee kinematics were regressed separately for the swing and stance phases using a generalized mixed effects model. Tibial anterior translation function was y=0.20x-3.09 for the swing phase and y=0.31x-0.54 for the stance phase, where x was the flexion angle and y was the tibial anterior translation. Tibial lateral and inferior translation were also regressed separately for the stance phase and the swing phase. Tibial external rotation was y=-0.002x^2+0.19x-0.64 for the swing phase and y=-0.19x-1.22 for the stance phase. The tibial adduction rotation function was also calculated separately for the stance and swing phase. The study presented three-dimensional coupled motion in the knee during the stance and swing phases of walking, and demonstrated the lateral pivoting motion found in previous studies. This expanded understanding of secondary knee motion functions will benefit musculoskeletal simulation and help improve the accuracy of calculated kinetics.
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http://dx.doi.org/10.1115/1.4043562DOI Listing
April 2019

Predicting body movements for person identification under different walking conditions.

Forensic Sci Int 2018 Sep 2;290:303-309. Epub 2018 Aug 2.

School of Mechanical Engineering, Chung-Ang University, Seoul, Republic of Korea. Electronic address:

Human motion during walking provides biometric information which can be utilized to quantify the similarity between two persons or identify a person. The purpose of this study was to develop a method for identifying a person using their walking motion when another walking motion under different conditions is given. This type of situation occurs frequently in forensic gait science. Twenty-eight subjects were asked to walk in a gait laboratory, and the positions of their joints were tracked using a three-dimensional motion capture system. The subjects repeated their walking motion both without a weight and with a tote bag weighing a total of 5% of their body weight in their right hand. The positions of 17 anatomical landmarks during two cycles of a gait trial were generated to form a gait vector. We developed two different linear transformation methods to determine the functional relationship between the normal gait vectors and the tote-bag gait vectors from the collected gait data, one using linear transformations and the other using partial least squares regression. These methods were validated by predicting the tote-bag gait vector given a normal gait vector of a person, accomplished by calculating the Euclidean distance between the predicted vector to the measured tote-bag gait vector of the same person. The mean values of the prediction scores for the two methods were 96.4 and 95.0, respectively. This study demonstrated the potential for identifying a person based on their walking motion, even under different walking conditions.
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http://dx.doi.org/10.1016/j.forsciint.2018.07.022DOI Listing
September 2018

Sex Differences in Pedobarographic Findings and Relationship between Radiographic and Pedobarographic Measurements in Young Healthy Adults.

Clin Orthop Surg 2018 Jun 18;10(2):216-224. Epub 2018 May 18.

Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.

Background: Although pedobarographic measurement is increasingly used for clinical and research purposes, relatively few published studies have investigated normative data. This study examined pedobarographic findings in young healthy adults with regard to sex-related differences and correlations among measurement indices.

Methods: Twenty young healthy adults (mean age, 22.4 years; standard deviation, 1.2 years; and 10 males and 10 females) were included. Weight bearing anteroposterior (AP) and lateral foot radiographs were taken, and dynamic pedobarographic data during treadmill walking and maximum ankle dorsiflexion were obtained. AP talo-first metatarsal angle, naviculocuboid overlap, lateral talo-first metatarsal angle, and plantar soft tissue thickness were measured on foot radiographs. Pedobarographic data including peak pressure and pressure-time integral were measured on five plantar segments: medial forefoot (MFF), lateral forefoot (LFF), medial midfoot (MMF), lateral midfoot (LMF), and heel.

Results: Male and female subjects significantly differed in body mass index (BMI, < 0.001), AP talo-first metatarsal angle ( = 0.018), soft tissue thickness under the metatarsal head ( = 0.040) and calcaneal tuberosity ( < 0.001), maximum dorsiflexion during stance phase ( = 0.041), peak pressure on the MFF ( = 0.005) and LFF ( = 0.004), and pressure-time integral on the MFF ( = 0.018) and heel ( = 0.001). BMI was significantly correlated with soft tissue thickness under the metatarsal head (r = 0.521, = 0.018) and calcaneal tuberosity (r = 0.585, = 0.007), peak pressure on the MFF (r = 0.601, = 0.005) and LFF (r = 0.487, = 0.029), pressure-time integral on the heel (r = 0.552, = 0.012), and total pressure-time integral (r = 0.755, < 0.001). Maximum dorsiflexion demonstrated significant negative correlations with pressure-time integral on the MFF (r = -0.595, = 0.007) and total pressure-time integral (r = -0.492, = 0.032). Pressure-time integral varus/valgus index was significantly correlated with pressuretime integral forefoot/heel index (r = 0.472, = 0.036).

Conclusions: Sex-related differences in pedobarographic examination were observed, which could provide useful information in setting appropriate treatment goals and obtaining appropriate control data. The effects of subtalar motion in distributing plantar pressure should be investigated in a future study.
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http://dx.doi.org/10.4055/cios.2018.10.2.216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5964271PMC
June 2018

Joint moments and contact forces in the foot during walking.

J Biomech 2018 06 26;74:79-85. Epub 2018 Apr 26.

School of Mechanical Engineering, Chung-Ang University, Seoul, Republic of Korea. Electronic address:

The net force and moment of a joint have been widely used to understand joint disease in the foot. Meanwhile, it does not reflect the physiological forces on muscles and contact surfaces. The objective of the study is to estimate active moments by muscles, passive moments by connective tissues and joint contact forces in the foot joints during walking. Joint kinematics and external forces of ten healthy subjects (all males, 24.7 ± 1.2 years) were acquired during walking. The data were entered into the five-segment musculoskeletal foot model to calculate muscle forces and joint contact forces of the foot joints using an inverse dynamics-based optimization. Joint reaction forces and active, passive and net moments of each joint were calculated from muscle and ligament forces. The maximum joint reaction forces were 8.72, 4.31, 2.65, and 3.41 body weight (BW) for the ankle, Chopart's, Lisfranc and metatarsophalangeal joints, respectively. Active and passive moments along with net moments were also obtained. The maximum net moments were 8.6, 8.4, 5.4 and 0.8%BW∙HT, respectively. While the trend of net moment was very similar between the four joints, the magnitudes and directions of the active and passive moments varied between joints. The active and passive moments during walking could reveal the roles of muscles and ligaments in each of the foot joints, which was not obvious in the net moment. This method may help narrow down the source of joint problems if applied to clinical studies.
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http://dx.doi.org/10.1016/j.jbiomech.2018.04.022DOI Listing
June 2018

Radiographic Measurements Associated With the Natural Progression of the Hallux Valgus During at Least 2 Years of Follow-up.

Foot Ankle Int 2018 04 10;39(4):463-470. Epub 2018 Jan 10.

2 Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea.

Background: This study aimed to investigate the radiographic measurements associated with the progression of hallux valgus during at least 2 years of follow-up.

Methods: Seventy adult patients with hallux valgus who were followed for at least 2 years and underwent weightbearing foot radiography were included. Radiographic measurements included the hallux valgus angle (HVA), hallux interphalangeal angle, intermetatarsal angle (IMA), metatarsus adductus angle, distal metatarsal articular angle (DMAA), tibial sesamoid position, anteroposterior (AP) talo-first metatarsal angle, and lateral talo-first metatarsal angle. Patients were divided into progressive and nonprogressive groups. Binary logistic regression analysis was performed to identify factors that significantly affected the progression of hallux valgus deformity. The correlation between change in HVA and changes in other radiographic indices during follow-up was analyzed.

Results: The DMAA ( P = .027) and AP talo-first metatarsal angle ( P = .034) at initial presentation were found to be significant factors affecting the progression of hallux valgus deformity. Change in the HVA during follow-up was significantly correlated with changes in the IMA ( r = 0.423; P = .001) and DMAA ( r = 0.541; P < .001).

Conclusion: The change in the HVA was found to be significantly correlated with changes in the IMA and DMAA. A future study is required to elucidate whether this correlation can be explained by the progressive instability of the first tarsometatarsal joint. We believe special attention needs to be paid to patients with pes planus and increased DMAA.

Level Of Evidence: Level III, comparative study.
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http://dx.doi.org/10.1177/1071100717745659DOI Listing
April 2018

Effectiveness of arthroscopically assisted surgery for ankle fractures: A meta-analysis.

Injury 2017 Oct 11;48(10):2318-2322. Epub 2017 Jul 11.

Department of Mechanical Engineering, Chung-Ang University, Seoul 06974, South Korea.

Introduction: This meta-analysis was performed to determine whether the arthroscopically assisted open reduction and internal fixation (ORIF) for ankle fractures is more beneficial than the conventional ORIF.

Methods: Articles in electronic medial databases were searched between March 1983 and August 2016, including Pubmed and SCOPUS. We included the studies with comparative design comparing the surgical outcomes between the arthroscopically assisted ORIF for ankle fractures and the conventional ORIF. Finally, two RCTs and two retrospective comparative studies were included for analysis. Mean and standard deviation (SD) of postoperative functional scores, number of subjects, and P-values were extracted from the studies. In addition, postoperative follow-up period, fracture type, and study quality were collected.

Results: The pooled effect size of the four studies 0.535 (95% CI, 0.247-0.823) in Hedges's g, which favored the arthroscopically assisted ORIF over conventional ORIF. There was no evidence of publication bias in funnel plot and in Egger's test (p=0.534).

Conclusion: The arthroscopically assisted ORIF for ankle fractures were more beneficial than the conventional ORIF in the current evidences. However, since it needs more medical cost and longer operation time, possible additional complications and cost effectiveness are to be validated in future studies.
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http://dx.doi.org/10.1016/j.injury.2017.07.011DOI Listing
October 2017

Dynamically adjustable foot-ground contact model to estimate ground reaction force during walking and running.

Gait Posture 2016 Mar 19;45:62-8. Epub 2016 Jan 19.

School of Mechanical Engineering, Chung-Ang University, Seoul, Republic of Korea. Electronic address:

Human dynamic models have been used to estimate joint kinetics during various activities. Kinetics estimation is in demand in sports and clinical applications where data on external forces, such as the ground reaction force (GRF), are not available. The purpose of this study was to estimate the GRF during gait by utilizing distance- and velocity-dependent force models between the foot and ground in an inverse-dynamics-based optimization. Ten males were tested as they walked at four different speeds on a force plate-embedded treadmill system. The full-GRF model whose foot-ground reaction elements were dynamically adjusted according to vertical displacement and anterior-posterior speed between the foot and ground was implemented in a full-body skeletal model. The model estimated the vertical and shear forces of the GRF from body kinematics. The shear-GRF model with dynamically adjustable shear reaction elements according to the input vertical force was also implemented in the foot of a full-body skeletal model. Shear forces of the GRF were estimated from body kinematics, vertical GRF, and center of pressure. The estimated full GRF had the lowest root mean square (RMS) errors at the slow walking speed (1.0m/s) with 4.2, 1.3, and 5.7% BW for anterior-posterior, medial-lateral, and vertical forces, respectively. The estimated shear forces were not significantly different between the full-GRF and shear-GRF models, but the RMS errors of the estimated knee joint kinetics were significantly lower for the shear-GRF model. Providing COP and vertical GRF with sensors, such as an insole-type pressure mat, can help estimate shear forces of the GRF and increase accuracy for estimation of joint kinetics.
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http://dx.doi.org/10.1016/j.gaitpost.2016.01.005DOI Listing
March 2016

Intra-Articular Knee Contact Force Estimation During Walking Using Force-Reaction Elements and Subject-Specific Joint Model.

J Biomech Eng 2016 Feb;138(2):021016

Joint contact forces measured with instrumented knee implants have not only revealed general patterns of joint loading but also showed individual variations that could be due to differences in anatomy and joint kinematics. Musculoskeletal human models for dynamic simulation have been utilized to understand body kinetics including joint moments, muscle tension, and knee contact forces. The objectives of this study were to develop a knee contact model which can predict knee contact forces using an inverse dynamics-based optimization solver and to investigate the effect of joint constraints on knee contact force prediction. A knee contact model was developed to include 32 reaction force elements on the surface of a tibial insert of a total knee replacement (TKR), which was embedded in a full-body musculoskeletal model. Various external measurements including motion data and external force data during walking trials of a subject with an instrumented knee implant were provided from the Sixth Grand Challenge Competition to Predict in vivo Knee Loads. Knee contact forces in the medial and lateral portions of the instrumented knee implant were also provided for the same walking trials. A knee contact model with a hinge joint and normal alignment could predict knee contact forces with root mean square errors (RMSEs) of 165 N and 288 N for the medial and lateral portions of the knee, respectively, and coefficients of determination (R2) of 0.70 and -0.63. When the degrees-of-freedom (DOF) of the knee and locations of leg markers were adjusted to account for the valgus lower-limb alignment of the subject, RMSE values improved to 144 N and 179 N, and R2 values improved to 0.77 and 0.37, respectively. The proposed knee contact model with subject-specific joint model could predict in vivo knee contact forces with reasonable accuracy. This model may contribute to the development and improvement of knee arthroplasty.
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http://dx.doi.org/10.1115/1.4032414DOI Listing
February 2016

Dynamic Three-Dimensional Analysis of Lachman Test for Anterior Cruciate Ligament Insufficiency: Analysis of Anteroposterior Motion of the Medial and Lateral Femoral Epicondyles.

Knee Surg Relat Res 2015 Sep 1;27(3):187-93. Epub 2015 Sep 1.

Department of Orthopaedic Surgery, Samsung Medical Center, Seoul, Korea.

Purpose: To evaluate dynamic three-dimensional (3D) kinematic properties of the anterior cruciate ligament (ACL)-insufficient knees and healthy contralateral knees in awake patients during the Lachman test using biplane fluoroscopy.

Materials And Methods: Ten patients with unilateral ACL-insufficient knees and healthy contralateral knees were enrolled in this study. Each patient underwent the Lachman test three times in the awake state. The knee joint motions were captured using biplane fluoroscopy. After manual registration of 3D surface data from 3D-computed tomography to biplane images, dynamic 3D kinematic data were analyzed.

Results: The average anteroposterior (AP) translation of the medial femoral epicondyle of the ACL-insufficient knees (11.5±4.2 mm) was significantly greater than that of the contralateral knees (7.7±3.5 mm) (p<0.05). However, there was no statistically significant side-to-side difference in the average AP translation of the lateral femoral epicondyle. During the Lachman test, the distal femur was more externally rotated than the proximal tibia, which showed significant difference between both sides.

Conclusions: During the Lachman test, the medial femoral epicondyle of the ACL-insufficient knee exhibited greater AP motion than that of the contralateral knee, whereas there was no significant side-to-side difference with regard to the AP motion of the lateral femoral epicondyle.
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http://dx.doi.org/10.5792/ksrr.2015.27.3.187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4570955PMC
September 2015

Plantar-flexion of the ankle joint complex in terminal stance is initiated by subtalar plantar-flexion: A bi-planar fluoroscopy study.

Gait Posture 2015 Oct 22;42(4):424-9. Epub 2015 Jul 22.

Department of Laboratory Medicine and Medical Device Clinical Trials Center, Chung-Ang University Hospital, Seoul, Republic of Korea.

Gross motion of the ankle joint complex (AJC) is a summation of the ankle and subtalar joints. Although AJC kinematics have been widely used to evaluate the function of the AJC, the coordinated movements of the ankle and subtalar joints are not well understood. The purpose of this study was to accurately quantify the individual kinematics of the ankle and subtalar joints in the intact foot during ground walking by using a bi-planar fluoroscopic system. Bi-planar fluoroscopic images of the foot and ankle during walking and standing were acquired from 10 healthy subjects. The three-dimensional movements of the tibia, talus, and calcaneus were calculated with a three-dimensional/two-dimensional registration method. The skeletal kinematics were quantified from 9% to 86% of the full stance phase because of the limited camera speed of the X-ray system. At the beginning of terminal stance, plantar-flexion of the AJC was initiated in the subtalar joint on average at 75% ranging from 62% to 76% of the stance phase, and plantar-flexion of the ankle joint did not start until 86% of the stance phase. The earlier change to plantar-flexion in the AJC than the ankle joint due to the early plantar-flexion in the subtalar joint was observed in 8 of the 10 subjects. This phenomenon could be explained by the absence of direct muscle insertion on the talus. Preceding subtalar plantar-flexion could contribute to efficient and stable ankle plantar-flexion by locking the midtarsal joint, but this explanation needs further investigation.
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http://dx.doi.org/10.1016/j.gaitpost.2015.07.009DOI Listing
October 2015

Concomitant Ankle Injuries Associated With Tibial Shaft Fractures.

Foot Ankle Int 2015 Oct 3;36(10):1209-14. Epub 2015 Jun 3.

Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea

Background: Ankle injuries associated with tibial shaft fractures can cause postoperative ankle pain and stiffness even when satisfactory bony union has been achieved. Although several previous studies have described these injuries, they have not been clearly defined or classified in terms of ankle injury type or need for surgical fixation.

Methods: Seventy-one consecutive patients (mean ± SD age, 48.3 ± 16.7 years; 37 men and 34 women) with tibial shaft fractures who underwent computed tomography examination were included. Data were collected including age, sex, body mass index, fracture location of the tibia and fibula (in percentile of length), tibial fracture shape (spiral, oblique, transverse), presence and pattern of concomitant ankle injuries (on the distal tibial articular surface), and necessity for surgical fixation of ankle injuries. Factors associated with concomitant ankle injuries associated with tibial shaft fractures were analyzed by logistic regression analysis.

Results: A total of 47 (64.7%) of the 71 tibial shaft fractures involved concomitant ankle injuries, including 8 cases of combined lateral malleolar fracture, posterior malleolar fracture, and anterior inferior tibiofibular ligament (AITFL) avulsion fracture; 9 cases of combined posterior malleolar fracture and AITFL avulsion fracture; 6 cases of combined lateral malleolar fracture and posterior malleolar fracture; 1 case of combined lateral malleolar fracture and AITFL avulsion fracture; 10 cases of posterior malleolar fracture; 7 cases of lateral malleolar fracture; 5 cases of AITFL avulsion fracture; and 1 unclassified fracture. Of these, 34 of the ankle injuries required surgical fixation. Spiral-type tibial shaft fracture was significantly associated with concomitant ankle injury (P = .001).

Conclusions: Orthopaedic surgeons should be aware that tibial shaft fractures, especially spiral-type fractures, are frequently associated with ankle injuries, such as lateral malleolar fractures, posterior malleolar fractures, and AITFL avulsion fractures. A considerable portion of these cases may necessitate surgical fixation. We recommend all spiral-type tibial shaft fractures routinely undergo computed tomography examination.

Level Of Evidence: Level III, comparative series.
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http://dx.doi.org/10.1177/1071100715588381DOI Listing
October 2015

Predicting anatomical landmarks and bone morphology of the femur using local region matching.

Int J Comput Assist Radiol Surg 2015 Nov 12;10(11):1711-9. Epub 2015 Feb 12.

Biomechanics Lab, School of Mechanical Engineering, Chung-Ang University, 84 Heukseokro, Dongjak-gu, Seoul, 156-756, Republic of Korea.

Purpose: Anatomical landmarks and bony features are frequently used in biomechanical and surgical applications. The purpose of this study was to develop a local region matching-based anatomical landmark prediction method.

Methods: A reference femur model with anatomical landmarks and a surface division map was prepared. Initial registration between the reference femur model and a target femur model was performed in three-dimensional Cartesian space, and closest point pairs were determined by the initial surface correspondence. The models were mapped to unit spheres through spherical parameterization. Spherical registration using the closest point pairs in the spherical parametric space enabled the application of a division map from the reference model to the target model. The reference and target models were divided into local regions defined in the division map, and the corresponding regions were again registered in Cartesian space. Anatomical landmarks in the local regions were identified in the target model.

Results: The accuracy of the proposed method was tested for anatomical landmarks marked by a clinician on 35 femoral models. The effectiveness of local region matching was demonstrated by automatic measurements of the femoral neck-shaft angle. The average prediction error for all eight anatomical landmarks of the femur was 2.74 (±1.78) mm. The average of the predicted neck-shaft angle for our Korean subjects was 126.41° (±4.92°), which was comparable to previous studies in Japanese and Chinese populations.

Conclusion: Anatomical landmarks and features could be accurately predicted using the proposed local region matching method. This method offers robustness and accuracy in determining anatomical bony landmarks and bone morphology for clinical and biomechanical applications.
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http://dx.doi.org/10.1007/s11548-015-1155-8DOI Listing
November 2015
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