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The objective of this study was to describe and classify common variations and compensation mechanisms in the sagittal alignment of the spine with lumbar degenerative disease.A total of 230 patients over 18 years old who underwent whole-spine X-rays to evaluate lower back pain were enrolled in this study. C7 slope, pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), cervical lordosis (CL), thoracolumbar kyphosis (TLK), and sagittal vertical axis (SVA) were measured. Patients were divided into Group A (balance without compensation), B (balance with compensation), C (unbalance with compensation), and D (unbalance without compensation) according to spinopelvic balance and thoracic compensation.Group A had the largest LL, smallest PT, largest SS, and best clinical parameters of the four groups (p 0.001, p 0.001, p 0.001, p 0.001). The age increased gradually from Group B to Group D. Group B had an increased TK compared with Group A (p 0.001). Group C had an increased TK compared with Group A (p 0.001). Group D had an increased C7 slope compared with Group A (p = 0.022).This classification is shown four different regional and global alignments of the spine. Compensation took place to keep the balance of the spine. Classification types were consistent with age, compensation abilities, and clinical parameters. This classification potentially represents a valuable tool for comprehensive analysis of lumbar degenerative before surgical treatment considering sagittal balance.

Background: The foramen tympanicum is located on the anteroinferior region of the external acoustic meatus and posteromedial to the temporomandibular joint in children between the first and the fifth year of life. It is considered an anatomical variation when it persists in adults. The aim of this study was to verify the prevalence as well as to characterize the foramen tympanicum in CT scans of the population from southeastern Brazil. Materials and methods: A total of 78 CT scans of dry human skulls were used, which were selected randomly regarding the ages, ranged from 15 to 100 years, and composed a total of 20 female and 58 males. The foramen tympanicum was identified in the images of the axial plane and confirmed in the images of the coronal and sagittal planes. The largest diameter (in mm) was obtained. The descriptive statistics (in %), Fisher's test and chi-square test (χ2) were performed to compare the prevalence of foramen tympanicum between sexes and sides. The probability value ≤ 0.05 was defined as a level of significance. Descriptive statistics were performed to verify the mean diameter of the foramen on the right and left sides of the skulls. Results: The prevalence of foramen tympanicum was higher in females (P = 0.0070), bilaterally, as the absolute values of females were lower in relation to males. Fisher's exact test showed that the prevalence of foramen tympanicum was significantly higher in females (45%) than in males (15.52%). On the right side, the mean axial diameter was 2.23 mm (range 0.93–3.75 mm). On the left side, the mean axial diameter was 2.22 mm (range 0.9–3.61 mm). Conclusions: The knowledge of anatomical variations is extremally valuable for an accurate diagnosis, treatment plan and prognosis and a thorough preoperative assessment.

Background The majority of fetal structural defects can be detected in the second trimester, thus this is the main time for screening for structural defects. 3D imaging of the fetal brain does not create a common part of this screening. Methods This prospective observational study was conducted at the Fetal Medicine Center of The Gynecological-Obstetrical Department of the University Hospital Olomouc in years 2017- 2020. The study sample was 451 consecutively scanned morphologically normal fetuses attending for routine second trimester anatomical survey at 20-22 weeks of pregnancy. A transabdominal 3D ultrasound volume acquisition of fetal brain was obtained from an axial and sagittal plane using skull sutures as an acoustic window. Results Both the corpus callosum (CC) and the vermis (VC) were detected in 51.7% of examinations in the sagittal plane, and in 31.7% in the axial plane. In 61.9% of the examinations, there was at least partial detection in both planes. Maternal BMI was found to be the only significant predictor of the quality of imaging in both planes. Conclusion 3D acquisition of fetal brain images in the sagittal plane followed by manipulation of acquired volume was valuable in assessment of corpus callosum and cerebellar vermis. This allows reconstruction of the sagittal plane that can be difficult to obtain in 2D imaging.

Background Surgical treatment of severe thoracolumbar kyphosis (TLK) secondary to late osteoporotic vertebral compression fracture (OVCF) presents several challenges to spine surgeons. Proper selection of distal fusion level is an important issue in surgical planning to decrease the likelihood of distal mechanical complications. This study was designed to compare the clinical and radiographic outcomes in elderly patients suffering from severe TLK related with late OVCF between different distal fusion strategies and to recommend a superior distal fusion level for these patients. Methods A total of 57 consecutive subjects with a minimum follow-up of two years were retrospectively reviewed. TLK was defined as the hyperkyphosis with an apex below T10. Severe TLK was defined as the Cobb angle of kyphosis ≥60°. Patients fused to sagittal stable vertebra (SSV) were assigned to Group SSV, while those fused to the vertebra above and below SSV were assigned to Groups SSV- and SSV+, respectively. Bone cement was used to enhance pedicle screw fixation. Clinical and radiographic results were collected and compared between different groups. Results Deformity corrections and living quality improvements at the latest follow-up were superior in Group SSV than Group SSV- with shorter fusion levels, while to the equal extent with Group SSV+ with longer fusion levels. 7 cases of distal complications were observed in Group SSV-. Negatively balanced lowest instrumented vertebra was revealed to be the independent factor predicting distal complications. Patients’ satisfaction of their surgical management was greater in Group SSV than Group SSV- (83.2 ± 4.4% vs. 70.5 ± 10.9%, P = 0.024), while comparable with Groups SSV + SSV+ (84.8 ± 5.7%). Conclusions Fusion to SSV with cement-augmented pedicle screws could limit the development of distal junctional mechanical complications after surgical treatment for severe TLK secondary to late OVCF in elderly patients, while achieves satisfactory deformity correction with the preservation of necessary lumbar motility.

This study develops a gait planning method for underactuated bipedal robot on uneven and compliant terrain. First, we employ a linear spring-damper model to describe foot-ground compliant contact, and establish a decoupled robotground three-dimensional dynamic mode. Second, based on a velocity-based bipedal stability definition and human walking characteristics, we propose a gait planning method to realize underactuated bipedal walking on uneven and compliant terrain. We decouple bipedal gait planning into sagittal and lateral master-slave ones. By planning the motion state of Center-of-Mass (CoM) of a robot, we make the movement of lateral and sagittal coincident such that bipedal walking is realized. Finally, underactuated bipedal walking with an average walking speed of 0.216 m/s and a step length of 183.9mm is realized on uneven terrain where the maximum height of unevenness is 32mm. The experimental results show that underactuated bipedal walking can be realized on uneven and compliant terrain by using the proposed method to control robot CoM and track its desired velocity.

Background Meniscal ramp lesion (RL) is the peripheral lesion of the posterior horn of the medial meniscus (PHMM) associated with anterior cruciate ligament (ACL) tear. The purpose of this study was to evaluate the accuracy of pre-operative magnetic resonance imaging (MRI) evaluation in diagnosing RL and to identify whether the difficulty in diagnosis differs depending on the location of RL. Methods ACL-injured patients undergoing ACL reconstruction from January 2017 to January 2019 were enrolled. A methodical arthroscopic exploration to identify RL was conducted intra-operatively using three steps, namely, the anterior visualization step, the inter-condylar visualization step, and the posteromedial step. The location of the RLs was evaluated and classified into two types as follows: Red-red zone (RR) - a meniscal tear of the red-red zone of the PHMM. Menisco-capsular junction (MCJ) - a lesion at the menisco-capsular junction of the PHMM, which is more peripheral than RR. Furthermore, the accuracy of 1.5-T MRI evaluation to diagnose RL by two testers using sagittal proton-density fat-saturated images was calculated. Results Of the 81 patients enrolled, 11 had RL: 5 cases each were at the MCJ and RR, and 1 case was at both locations. The sensitivity of MRI for detecting RL was 27.3–45.5%, whereas the specificity was 84.3–95.7% in total. The sensitivity of MRI in detecting RL at the RR and MCJ was 40.0–80.0%, 0–20.0%, respectively. The intra-observer reliability of the MRI evaluation was moderate (κ coefficient: 0.40–0.46), while the inter-observer reliability was fair to moderate (κ coefficient: 0.27–0.41). Conclusions A low sensitivity of the MRI in detecting RL at the MCJ was observed, and the reliability of the MRI evaluation for diagnosis of RL was not high. Therefore, methodical arthroscopic exploration is essential to diagnose RL even when it is not suspected on pre-operative MRI.

Local-area cartilage segmentation (LACS) software was developed to segment medial femur (MF) cartilage on magnetic resonance imaging (MRI). Our objectives were 1) to extend LACS to the lateral femur (LF), medial tibia (MT), and lateral tibia (LT), 2) to compare LACS to an established manual segmentation method, and 3) to visualize cartilage responsiveness over each cartilage plate.Osteoarthritis Initiative participants with symptomatic knee osteoarthritis (OA) were selected, including knees selected at random (n = 40) and knees identified with loss of cartilage based on manual segmentation (Chondrometrics GmbH), an enriched sample of 126 knees. LACS was used to segment cartilage in the MF, LF, MT, and LT on sagittal 3D double-echo steady-state MRI scans at baseline and at 2-year follow-up. We compared LACS and Chondrometrics average thickness measures by estimating the correlation in each cartilage plate and estimating the standardized response mean (SRM) for 2-year cartilage change. We illustrated cartilage loss topographically with SRM heatmaps.The estimated correlation between LACS and Chondrometrics measures was r = 0.91 (95% confidence interval [95% CI] 0.86, 0.94) for LF, r = 0.93 (95% CI 0.89, 0.95) for MF, r = 0.97 (95% CI 0.96, 0.98) for LT, and r = 0.87 (95% CI 0.81, 0.91) for MT. Estimated SRMs for LACS and Chondrometrics measures were similar in the random sample, and SRM heatmaps identified subregions of LACS-measured cartilage loss.LACS cartilage thickness measurement in the MF and LF and tibia correlated well with established manual segmentation-based measurement, with similar responsiveness to change, among knees with symptomatic knee OA. LACS measurement of cartilage plate topography enables spatiotemporal analysis of cartilage loss in future knee OA studies.

The range of internal rotation sometimes deteriorates after reverse total shoulder arthroplasty; however, the underlying mechanisms remain unclear. This study aimed to investigate the association between sagittal spinal alignment and internal rotation deterioration after reverse total shoulder arthroplasty.We retrospectively reviewed 52 patients who underwent reverse total shoulder arthroplasty by a single surgeon between October 2014 and December 2018. The sagittal spine was radiographed, and the sagittal spinal alignment was evaluated based on 10 parameters (e.g. C7-HA: the distance between the plumb line from the center of the seventh cervical vertebral body and the center of the hip axis). We divided the patients into two groups, group A (internal rotation deterioration; 23 patients) and B (without internal rotation deterioration; 29 patients). Logistic regression analysis was performed to analyze the association between sagittal spinal alignment and internal rotation deterioration after reverse total shoulder arthroplasty, and a receiver operating characteristic curve was used to analyse the cutoff value of independent variables that was correlated with IR deterioration.Logistic regression analysis demonstrated the correlation between C7-HA and internal rotation deterioration (odds ratio, 1.95; 95% confidence interval, 1.33-2.84; P 0.001). The receiver operating characteristic curve suggested that when C7-HA was at least 2.44 cm, it was strongly correlated with deterioration of internal rotation (sensitivity, 91.3%; specificity, 93.1%; P 0.001; area under the curve, 0.938). Group A was significantly inferior to group B in not only internal rotation but also flexion and abduction.This study suggested that a remarkably positive value in C7-HA was a factor that was correlated with deterioration of internal rotation. In addition, the deformation of sagittal spinal alignment would impact on the range of motion after reverse total shoulder arthroplasty.

Study Design: Retrospective observational study.Purpose: In this study we identify risk factors, including patient demographics, sagittal parameters, and clinical examinations, affecting incomplete L5/S posterior lumbar interbody fusion (PLIF).Overview of Literature: The lumbosacral spine is considered to have an interbody fusion rate lower than that of the lumbar spine, but few studies have investigated the cause, including investigating the pelvis. We believe that pelvic morphology can affect L5/S interbody fusion of the lumbosacral spine.Methods: We observed 141 patients (61 men, 80 women; average age, 65.8 years) who had undergone PLIF and checked for the presence of L5/S interbody fusion. We investigated factors such as age, gender, the presence of diffuse idiopathic skeletal hyperostosis (DISH), fusion level, and grade 2 osteotomy, as well as pre-, post-, and post−preoperative L5/S disk height and angle, lumbar lordosis, Visual Analog Scale (VAS) score, Japanese Orthopaedic Association (JOA) score, and pelvic incidence (PI), comparing those with and without L5/S interbody fusion. In addition, we analyzed the patients classified into short-level (n=111) and multi-level fusion groups (n=30).Results: Overall, the L5/S interbody fusion rate was 70% (short-level, 78%; multi-level, 40%). Age and pre- and post−preoperative L5/S disk angle were significantly different in each fusion level group. DISH presence, grade 2 osteotomy, and postoperative VAS and JOA scores were significantly different in the short-level fusion group, whereas PI was significantly different in the multi-level fusion group.Conclusions: Incomplete union after L5/S PLIF correlates with advanced age, many fusion levels, and a large value of preoperative and a small value of post−preoperative L5/S disk angles.

Background: Aim of the present study is to analyze the demographic and anatomical details of the Huschke’s foramen (HF) which are not previously studied and to present a new clinical perspective. Materials and methods: MDCT (Multidedector Computed Tomography) images of 495 patients obtained were retrospectively evaluated. Presence of a HF, its’ size, relations of it with side, age and gender were noted for every patient. Size of the foramen was measured in the axial plane, as well as on the reconstructed coronal and sagittal planes. Results: Of the 495 patients 99 (20%) had HF. There was no significant difference between females and males according to the presence of the HF and the side of the HF. When the dimension of the left- and the right-sided HFs were compared, there were no significant differences on none of the axes for the patients with unilateral or bilateral HF. There was no significant linear correlation between age and the dimension on axial axis, the dimension on the sagittal axis and the dimension on the coronal axis Conclusions: The present work presenting morphologic and statistical variables of HF provides a data for further studies which will indicate risk factor of herniation through HF. By the aid of MDCT which is sensitive for detection of the HF because of its thin sections, high spatial resolution, and multiplanar capabilities, lesions which were previously diagnosed as dehiscence were found to be defects.

Measurement of human body movement is an essential step in biomechanical analysis. The current standard for human motion capture systems uses infrared cameras to track reflective markers placed on the subject. While these systems can accurately track joint kinematics, the analyses are spatially limited to the lab environment. Though Inertial Measurement Unit (IMU) can eliminate the spatial limitations of the motion capture system, those systems are impractical for use in daily living due to the need for many sensors, typically one per body segment. Due to the need for practical and accurate estimation of joint kinematics, this study implements a reduced number of IMU sensors and employs machine learning algorithm to map sensor data to joint angles. Our developed algorithm estimates hip, knee, and ankle angles in the sagittal plane using two shoe-mounted IMU sensors in different practical walking conditions: treadmill, level overground, stair, and slope conditions. Specifically, we proposed five deep learning networks that use combinations of Convolutional Neural Networks (CNN) and Gated Recurrent Unit (GRU) based Recurrent Neural Networks (RNN) as base learners for our framework. Using those five baseline models, we proposed a novel framework, DeepBBWAE-Net, that implements ensemble techniques such as bagging, boosting, and weighted averaging to improve kinematic predictions. DeepBBWAE-Net predicts joint kinematics for the three joint angles under all the walking conditions with a Root Mean Square Error (RMSE) 6.93-29.0% lower than base models individually. This is the first study that uses a reduced number of IMU sensors to estimate kinematics in multiple walking environments.

The rise in the occurrence of musculoskeletal disorders, such as thoracic hyperkyphosis (THK) or lumbar hypolordosis (LHL), is a result of demographic changes. Exercise therapy is an effective approach that can reduce related disabilities and costs. To ensure successful therapy, an individualized exercise program adapted to the severity of the disorder is expedient. Nevertheless, appropriate classification systems are scarce. This project aimed to develop and evaluate a severity classification focused on exercise therapy for patients with THK or LHL. A multilevel severity classification was developed and evaluated by means of an online survey. Reference limits of spinal shape angles were established by data from video rasterstereography of 201 healthy participants. A mean kyphosis angle of 50.03° and an average lordosis angle of 40.72° were calculated as healthy references. The strength of the multilevel classification consisting of the combination of subjective pain and objective spinal shape factors was confirmed by the survey (70% agreement). In particular, the included pain parameters were considered relevant by 78% of the experts. Even though the results of the survey provide important evidence for further analyses and optimization options of the classification system, the current version is still acceptable as therapeutic support.

Objective To examine the effects of shoe-stiffening inserts on lower limb kinematics in individuals with first metatarsophalangeal (MTP) joint osteoarthritis (OA). Methods Forty-eight individuals with radiographically confirmed first MTP joint OA (24 males and 24 females; mean age 57.8 years, standard deviation 10.5) were randomized to receive either shoe-stiffening inserts or sham inserts, and underwent gait analysis during level walking using a 10-camera infrared Vicon motion analysis system. Sagittal plane kinematics of the first MTP, ankle, knee, and hip joints were compared between the shoe only (control) and insert conditions in both groups (within-groups) and between both insert conditions (between-groups). Results Compared to the shoe only condition, the sham insert reduced knee flexion and total excursion, and the shoe-stiffening insert reduced first MTP joint maximum dorsiflexion and ankle joint maximum plantarflexion, and increased maximum knee flexion and total excursion. Between-group comparisons indicated that the shoe-stiffening inserts significantly decreased first MTP joint maximum dorsiflexion, ankle joint maximum plantarflexion and total excursion, and increased knee joint maximum flexion and total excursion compared to the sham inserts. Conclusion Carbon fibre shoe-stiffening inserts significantly alter sagittal plane lower limb joint kinematics during walking, particularly first MTP joint maximum dorsiflexion. These findings provide insights into the mechanisms that may be responsible for their clinical effectiveness in the treatment of first MTP joint OA, and potentially explain changes in symptoms in other lower limb joints.

BACKGROUND Syndesmosis measurments and indices have been controversial and showed interindividual variability. The purpose of this study was to analyze, by conventional axial computed tomography images and a simulated load device, the uninjured tibiofibular syndesmosis under axial force and forced foot positions. METHODS A total of 15 healthy patients (30 ankles) were studied using adjustable simulated load device (ASLD). This device allowed to perform bilateral ankle CT scans in two forced foot and ankle positions (30° of plantar flexion, 15° of inversion, 20° of internal rotation and 15° of dorsal flexion, 15° of eversion, 30° of external rotation). Axial load was applied simultaneously in a controlled manner (70% body weight). Measurements on the axial image of computed tomography were: syndesmotic area (SA), fibular rotation (FR), position of the fibula in the sagittal plane (FPS), depth of the incisura (ID) and direct anterior difference (ADD), direct middle difference (MDD) and direct posterior difference (PDD). RESULTS In patients without injury to the tibiofibular syndesmosis, the application of axial load and forced foot and ankle positions showed statistically significant differences on the distal tibiofibular measurements between the stressed and the relaxed position, it also showed interindividual variability : SA (median = 4.12 [IQR = 2.42, 6.63]) (p < 0.001), ADD (0.67 [0.14, 0.67]) (p < 0.001), MDD(0.45, [0.05, 0.9]) (p < 0.001), PDD (0.73 [-0.05, 0.73]) (p < 0.002). However, it did not detect statistically significant differences when the tibiofibular differences between the stressed and the relaxed position in one ankle were compared with the contralateral side: SA (-0.14, SD = 4.33 [95% CI = -2.53, 2.26]), ADD (-0.42, 1.08 [-1.02, 0.18]), MDD (0.29, 0.54 [-0.01, 0.59]), PDD (-0.1, 1.42 [-0.89, 0.68]). Interobserver reliability showed an Intraclass correlation coefficient of 0.990 [95% CI = 0.972, 0.997]. CONCLUSIONS Wide interindividual variability was observed in all syndesmotic measurements, but no statistically significant differences were found when comparing one ankle to the contralateral side. Measuring syndesmosis alignment parameters, may only be of value, if those are compared to the contralateral ankle.

Background Proper identification of lumbosacral transitional vertebrae (LSTV) is important to characterize the relationship between the transitional segment and adjacent levels. Classical classification schemes are inaccurate with respect to the whole spine. We propose a precise vertebral numbering method and investigated the relationship between LSTV and whole-body sagittal alignment. Methods A total of 291 healthy adult volunteers with no history of spinal disease were evaluated with biplanar slot scanning full body stereoradiography to determine the prevalence of LSTV. Vertebrae were counted from the first cervical vertebra using both coronal and sagittal plane images. We then investigated the influence of LSTV on whole-body sagittal alignment in 279 participants. Whole-body key parameters descriptive statistics were compared among groups according to the number of vertebrae (L4, L5, and L6). Statistical analysis was performed between normal and LSTV cases using the Steel-Dwass analysis. Results Of the 291 subjects, 14 (4.8%) had 23 vertebrae and 16 (5.5%) had 25 vertebrae. Eleven (3.8%) had Th11, 3 (1.0%) had L4, and 1 (0.3%) had Th11 + L6, 16 (5.5%) had L6. Compared with the normal group, the sacral base in relation to the pelvis was higher in the L4 group and lower in the L6 group. The C2–C7 angle and lumbar lordosis (LL) were increased in both the L4 and L6 groups. All remaining parameters were decreased in the L4 group and increased in the L6 group. The relationship between LL and PI was similar in the normal and LSTV groups, despite the difference in the sacral base location. Conclusions We propose a precise method for numbering the vertebrae using coronal and sagittal full body images. The spinopelvic parameters of the LSTV population significantly differed from those in the normal spine population due to differences in the sacral base location.

Study Design: This is a retrospective study.Purpose: This study aims to evaluate the risk factor associated with pseudoarthrosis after placement of lateral interbody fusion (LIF) cages for adult spinal deformity (ASD) treatment. Overview of Literature: LIF technique is widely used for ASD correction. Furthermore, pseudoarthrosis is a major complication of fusion surgery required for revision surgery.Methods: This study included 42 patients with ASD (two men and 40 women; 112 segments; mean, 68.5±8.4 years; and mean follow-up, 31.6±17.0 months) who underwent LIF and posterior correction surgery. The concave slot of the LIF cage was filled with an autologous iliac crest bone graft (IBG), and the convex slot with a porous hydroxyapatite/collagen (HAp/Col) composite was soaked with bone marrow aspirate. Endplate injury, the gap between vertebral endplate and cage in the coronal or sagittal plane, and fusion status were evaluated using computed tomography multiplanar reconstruction at 12 months after surgery. Moreover, the associated risk factors for pseudoarthrosis were analyzed.Results: Fusion at LIF segments were observed in 71.4% segments at 12 months after surgery. Fusion on the concave slot (autologous IBG side), convex slot (porous HAp/Col composite side), and both concave and convex slots were observed in 66.1%, 37.5%, and 36.6% of patients, respectively. Moreover, pseudoarthrosis was observed in 28.6% at 12 months after surgery. Consequently, logistic regression analysis of the fusion at the LIF segment revealed that the gap between the LIF cage and endplate in the coronal plane (p=0.030; odds ratio, 0.183; 95% confidence interval, 0.030–0.183) was significantly associated with pseudoarthrosis at the LIF segments.Conclusions: ASD surgery fusion rate using LIF cages was 71.4% at 12 months after surgery. The fusion rate was higher on the concave slot filled with autologous IBG than on the convex slot filled with a porous HAp/Col composite. The gap in the coronal plane was a risk factor for pseudoarthrosis at the LIF segment.

Compensatory changes in cervical sagittal alignment after C1-C2 arthrodesis have been reported in a few studies. No studies have explored the differences in these compensatory changes between traumatic and non-traumatic pathologies. Conflicting reports exist on the correlation between cervical sagittal parameters and neck pain or function.Medical records of 81 consecutive patients [Jan 2010-Dec 2018] who underwent Harms arthrodesis were retrospectively reviewed. 53 patients were included in the final analysis. Radiological parameters [C0-C1, C1-C2, C2-C7 angles and T1 slope] and clinical parameters [VAS (Visual analogue scale) and NDI (Neck disability index)] were compared between the two groups, Group A (traumatic) and Group B (non-traumatic).The 53 patients [Group A (The sub-axial sagittal profile was strongly correlated with the ΔC1-C2 angle in both groups. Group B showed greater changes in sagittal parameters after Harms fixation and Group A showed greater improvement in long-term functional outcomes. The final functional outcomes were not related to the initial or final radiological sagittal profile in both groups.

Purpose Anterior cruciate ligament (ACL) injury induces anterior and rotatory instability of the knee. However, the effect of this instability on the stress distribution in the knee joint in living participants is not clear. The aim of this study was to compare the distribution pattern of subchondral bone density across the proximal tibia in the knees with and without ACL injury, and to investigate the correlation between the distribution patterns of the subchondral bone density and the duration of ACL-deficiency. Methods Radiographic and computed tomography (CT) data pertaining to 20 patients with unilateral ACL injury without combined injury (ACL-deficient group) and 19 nontraumatic subjects (control group) were collected retrospectively. Subchondral bone density of the proximal tibia was assessed using CT-osteoabsorptiometry. Both the medial and lateral compartments of the proximal tibia were divided into three subregions of equal width in the sagittal direction. The percentage of high subchondral bone density areas (HDA%) in each subregion was quantitatively analyzed. Results HDA% of the posteromedial region was significantly higher in the ACL-deficient group (mean: 21.6%) than in the control group (14.7%) (p = 0.002). In contrast, HDA% of the anteromedial region was significantly lower in the ACL-deficient group (9.4%) than in the control group (15.3%) (p = 0.048). The logarithm of the time elapsed from ACL injury to CT examination showed a significant correlation with HDA% in the posteromedial region (p = 0.032). Conclusions Subchondral bone density in the posteromedial region significantly increased after ACL injury and correlated with the duration of ACL-deficiency in semi-log manner in meniscus intact knees. The increase in stress on the posteromedial region after ACL injury, which induces a change in the subchondral bone density, justifies early ACL reconstruction after ACL injury.

Background context Recently, the number of patients with lumbar spinal stenosis (LSS) who present with a coexisting spinal deformity such as degenerative spondylolisthesis (DS) and scoliosis (DLS) has been increasing. Lumbar decompression without fusion can lead to a reactive improvement in the lumbar and sagittal spinopelvic alignment, even if a sagittal imbalance exists preoperatively. However, the mid- to long-term impact of the coexistence of DS and DLS on the change in sagittal spinopelvic alignment and clinical outcomes after decompression surgery remains unknown. Purpose This study aimed to investigate whether the coexistence of DS or DLS in patients with LSS is associated with differences in radiological and clinical outcomes after minimally invasive lumbar decompression surgery. Study design/setting A retrospective analysis of prospectively collected data. Patient sample A total of 169 patients who underwent minimally invasive lumbar decompression surgery and follow-up >5 years postoperatively. Outcome measures Self-report measures: Low back pain (LBP)/leg pain/leg numbness visual analog scale (VAS) scores and the Japanese Orthopedic Association scores Physiologic measures: Standing sagittal spinopelvic alignment METHODS: In total, 81 patients with LSS, 50 patients with LSS and DS (≥3 mm anterior slippage), and 38 patients with LSS and DLS (≥15° coronal Cobb angle) were included in the current study. Clinical and radiological outcome results before surgery and at 2 and 5 years after surgery were compared among the groups. Results In patients with LSS with coexisting DS, the clinical outcomes at 2 and 5 years after surgery were similar to those of patients with only LSS. In patients with LSS with coexisting DLS, the VAS LBP and leg pain at 2 years after surgery was significantly higher (34.7 vs 27.8, P=0.014; 27.8 vs 14.7, P=0.028) and the achievement rate of the minimal clinically important difference in VAS LBP and leg pain was significantly lower than that of the LSS group (36.1% vs 54.2%, P=0.036; 58.3% vs 69.9%, P=0.10). The clinical outcomes except VAS leg numbness at 5 years after surgery were similar to those of patients with only LSS. The reoperation rate of the DS group was significantly lower than that of the LSS group (4.0% vs 14.8%; P=0.01); however, the reoperation rate of the DLS group was comparable to that of the LSS group (15.8% vs 14.8%; P=0.493). Lumbar lordosis (LL), sacral slope, pelvic tilt, and pelvic incidence-LL had significantly improved and been maintained for 5 years after the surgery in both the DS and the DLS groups. The sagittal vertical axis had improved at 2-year follow-up; however, no significant difference was observed at the 5-year follow-up in both the DS and the DLS groups. Conclusion Mid-term clinical outcomes in patients with LSS with and without deformity were comparable. Lumbar decompression without fusion can result in a reactive improvement in the lumbar and sagittal spinopelvic alignment, even with coexisting DS or DLS. Minimally invasive surgery could be considered for most patients with LSS.

Background The femoral anterior tangent (FAT) line refers to a line parallel to the anterior surface of the distal femur in the axial plane. This study aimed to evaluate the effectiveness of a new operation support system which uses the FAT line to set the femoral component rotational alignment in total knee arthroplasty (TKA). Methods A total of 170 consecutive knees in 139 patients undergoing primary TKA with the JIGEN (Jig Engaged Three-dimensional (3D) Pre-Operative Planning Software for TKA) operation support system was examined. The JIGEN system creates 3D models of bones using computed tomography data, allowing for surgical simulations such as positioning of implants while calculating positions of the intramedullary alignment rod (IM rod) and surgical jig. We retrospectively analyzed the FAT line angle relative to the surgical epicondylar axis (SEA) on the axis plane perpendicular to the IM rod and evaluated the accuracy of the femoral component alignment after TKA with the 3D measurement system. Results The FAT line was 9.6° ± 3.7° (range, 1.4°–20.4°) internally rotated relative to the SEA. The average absolute error was 1.4° ± 1.1° in the coronal plane, 2.0° ± 1.5° in the sagittal plane, and 1.6° ± 1.3° in the axial plane. The femoral component outliers (i.e., >3° away from the goal alignment) were 7.7% in the coronal plane, 20.6% in the sagittal plane, and 10.3% in the axial plane. Conclusions Our findings suggest that the FAT line is a reliable and reproducibly identifiable axis for the accurate determination of proper rotational alignment in TKA. An operation support system which uses the FAT line for determining intraoperative femoral component rotation can effectively achieve highly accurate positioning of the femoral component in TKA.

OBJECTIVE Roussouly lumbopelvic sagittal profiles are associated with distinct pathologies or distinct natural histories and prognoses. The associations between developmental lumbar spinal stenosis (DLSS) and native lumbopelvic sagittal profiles are unknown. Moreover, the relative effects of multilevel decompression on lumbar sagittal alignment, geometrical parameters of the pelvis, and compensatory mechanisms for each of the Roussouly subtypes are unknown. This study aimed to explore the association between DLSS and native lumbar lordosis (LL) subtypes. It also attempts to understand the natural history of postlaminectomy lumbopelvic sagittal changes and compensatory mechanisms for each of the Roussouly subtypes and to define the critical lumbar segment or specific lordosis arc that is recruited after relief of the stenosis effect. METHODS A total of 418 patients with multilevel DLSS were grouped into various Roussouly subtypes, and lumbopelvic sagittal parameters were prospectively compared at follow-up intervals of preoperative to < 2 years, 2 to < 5 years, and 5 to ≥ 10 years after laminectomy. The variables analyzed included LL, upper lordosis arc from L1 to L4, lower lordosis arc from L4 to S1, and segmental lordosis from L1 to S1. Pelvic parameters included pelvic incidence, sacral slope, pelvic tilt, and pelvic incidence minus LL values. RESULTS Of the 329 patients who were followed up throughout this study, 33.7% had Roussouly type 1 native lordosis, whereas the incidence rates of types 2, 3, and 4 were 33.4%, 21.9%, and 10.9%, respectively. LL was not reduced in any of the Roussouly subtypes after multilevel decompressions. Instead, LL increased by 4.5° (SD 11.9°—from 27.3° [SD 11.5°] to 31.8° [SD 9.8°]) in Roussouly type 1 and by 3.1° (SD 11.6°—from 41.3° [SD 9.5°] to 44.4° [SD = 9.7°]) in Roussouly type 2. The other Roussouly types showed no significant changes. Pelvic tilt decreased significantly—by 2.8°, whereas sacral slope increased significantly—by 2.9° in Roussouly type 1 and by 1.7° in Roussouly type 2. The critical lumbar segment that recruits LL differs between Roussouly subtypes. Increments and changes were sustained until the final follow-up. CONCLUSIONS The study findings are important in predicting patient prognosis, LL evolution, and the need for prophylactic or corrective deformity surgery. Multilevel involvement in DLSS and the high prevalence of Roussouly types 1 and 2 suggest that spinal canal dimensions are closely linked to the developmental evolution of LL.

Background The K-line in the neck-flexed position (FK-line) on radiography reflects dynamic factors and cervical alignment. Although the FK-line has been reported to affect the neurological recovery after muscle-preserving selective laminectomy for cervical spondylotic myelopathy (CSM), its influence on surgical outcomes after expansive open-door laminoplasty (ELAP) has not been investigated. Methods We reviewed the surgical outcomes in 81 patients with multilevel CSM who underwent C4–C6 ELAP combined with C3 and C7 partial laminectomy using a laminoplasty plate and were followed up for at least 2 years. We defined the K-line (−) as some portion of a bony spur or the vertebral body crossing the FK-line, whereas the FK-line (+) was defined as that never crossing the FK-line. Patients were divided into the FK-line (+) (n = 61) and FK-line (−) groups (n = 20), and the surgical outcomes were compared between the groups. A multivariate analysis was performed to identify the factors that influenced the neurological outcomes. Results The FK-line (−) group had a smaller C2–C7 angle, smaller C7 slope, greater postoperative increase in the C2–C7 sagittal vertical axis, greater kyphosis in cervical flexion and less lordosis in cervical extension, and higher incidence of postoperative residual spinal cord compression. The preoperative-to-postoperative changes in the Japanese Orthopedic Association (JOA) score and JOA score recovery rate (RR) were lower in the FK-line (−) group. The multiple linear regression analysis revealed that the K-line (−) (β = −0.327, P = 0.011) and high signal intensity (SI) changes on T2-weighted imaging (WI) combined with the low SI changes on T1-WI in the spinal cord (β = −0.320, P = 0.013) negatively affected the JOA score RR. Conclusions The FK-line can be used for patients with CSM as a simple indicator of neurological outcomes after ELAP.

OBJECTIVE Previous reports have focused on the complications of L5 nerve root injury caused by anterolateral misplacement of the S1 pedicle screws. Anatomical knowledge of the L5 nerve root in the pelvis is essential for safe and effective placement of the sacral screw. This cadaveric study aimed to investigate the course of the L5 nerve root in the pelvis and to clarify a safe zone for inserting the sacral screw. METHODS Fifty-four L5 nerve roots located bilaterally in 27 formalin-fixed cadavers were studied. The ventral rami of the L5 nerve roots were dissected along their courses from the intervertebral foramina to the lesser pelvis. The running angles of the L5 nerve roots from the centerline were measured in the coronal plane. In addition, the distances from the ala of the sacrum to the L5 nerve roots were measured in the sagittal plane. RESULTS The authors found that the running angles of the L5 nerve roots changed at the most anterior surface of the ala of the sacrum. The angles of the bilateral L5 nerve roots from the right and left L5 intervertebral foramina to their inflection points were 13.77° ± 5.01° and 14.65° ± 4.71°, respectively. The angles of the bilateral L5 nerve roots from the right and left inflection points to the lesser pelvis were 19.66° ± 6.40° and 20.58° ± 5.78°, respectively. There were no significant differences between the angles measured in the right and left nerve roots. The majority of the L5 nerves coursed outward after changing their angles at the inflection point. The distances from the ala of the sacrum to the L5 nerve roots in the sagittal plane were less than 1 mm in all cases, which indicated that the L5 nerve roots were positioned close to the ala of the sacrum and had poor mobility. CONCLUSIONS All of the L5 nerve roots coursed outward after exiting the intervertebral foramina and never inward. To prevent iatrogenic L5 nerve root injury, surgeons should insert the S1 pedicle screw medially with an angle > 0° toward the inside of the S1 anterior foramina and the sacral alar screw laterally with an angle > 30°.

Objective: We aimed to investigate the feasibility of multi-acquisition with variable resonance image combination slab selectivity inversion recovery (MAVRIC SL IR) sequence on 3.0 T MRI in patients with anterior cervical discectomy and fusion (ACDF) surgery compared to bandwidth-optimized short tau inversion recovery (STIR) sequence. Methods: Paired sagittal MR images of MAVRIC SL IR and bandwidth-optimized STIR sequences were acquired and analyzed for 21 patients after ACDF surgery with PEEK cage-plate construct. Quantitative comparisons were made on the metal artifact areas of paired mid-sagittal images. In qualitative analysis, the consistency of fat suppression and visibility of anatomic structures (bonemetal interface, surrounding soft tissues, and spinal cord) were independently assessed, based on a five-point scale by two musculoskeletal radiologists, who were blind to the images and patient details. Results: The application of the MAVRIC SL IR sequence resulted in a significant reduction of 48% in the mean area of metal artifacts (t = -7.141, p < 0.001). Based on the comments received from both the reviewers, the MAVRIC SL IR sequence showed greater visibility of the bone-metal interface (p < 0.001), considerable visibility of the surrounding soft tissues (p > 0.05) but worse visibility of the spinal cord (p < 0.001), including the consistency of fat suppression (p < 0.001) relative to the bandwidth-optimized STIR sequence. Conclusion: With significantly reduced metal artifacts, the MAVRIC SL IR sequence can be implemented in patients undergoing ACDF surgery with PEEK cage-plate construct for 3.0 T MRI, despite the poor visibility of the spinal cord.

Study Design: Cross-sectional observational study.Purpose: To examine whether pelvic rotation as a compensatory mechanism for sagittal imbalance is related to quality of life (QOL).Overview of Literature: Poor sagittal alignment is associated with compensatory pelvic retroversion and decreased QOL. Whether the compensatory pelvic tilt (PT) influences QOL is unclear.Methods: Overall, 134 subjects aged ≥20 years with lower back pain were included (104 females; mean age, 70±9.8 years). Sagittal vertical alignment (SVA) and PT were analyzed radiographically. Patients were stratified into three groups based on SVA values: good alignment (group G), intermediate alignment (group I), and poor sagittal alignment (group P). Patients in group I were further categorized into two groups: low PT and high PT. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for clinical assessment, and the scores were compared between groups.Results: As SVA increased, PT and lumbar lordosis (LL) increased and decreased, respectively. PT and LL differed significantly between groups G and P (pp

Background To measure the motion of polyethylene insert and implant components of mobile-bearing total ankle replacement (TAR) by cone-beam CT scanning. Methods 10 TAR patients with high amount of clinical motion after the CCI implant (Ceramic Coated Implant; Wright Medical Technology, Arlington, TN, USA) with average age at operation 64,3 years (range 47–84) and average clinical total range of motion 42 degrees (range 35–55) were included. Results The average total range of motion between the insert and the tibial component was 0.8 mm (range 0–2) in the coronal plane, and 2.9 mm (range 1–6) in the sagittal plane. There was wide variation in the axial rotation measurements between the components. Conclusion We found measurable motion between the mobile-bearing insert and the tibial component in all planes. The relevance of this motion to the function and long-term survival of the TAR remains to be determined.

OBJECTIVE Three-column osteotomy (3CO) is used for severe spinal deformities. Associated complications include sagittal translation (ST), which can lead to neurological symptoms. Mismatch between the surgical center of rotation (COR) and the concept of the ideal COR is a potential cause of ST. Matching surgical with conceptual COR is difficult with pedicle subtraction osteotomy (PSO) and vertebral column resection (VCR). This mismatch influences correction geometry, which can prevent maximum possible correction. The authors’ objective was to examine the sagittal correction geometry and surgical COR of thoracic and lumbar 3CO. METHODS In a retrospective study of patients with PSO or VCR for severe sagittal plane deformity, analysis of surgical COR was performed using pre- and postoperative CT scans in the PSO group and digital radiographs in the VCR group. Radiographic analysis included standard deformity measurements and regional kyphosis angle (RKA). All patients had 2-year follow-up, including neurological outcome. Preoperative CT scans were studied for rigid osteotomy sites versus mobile osteotomy sites. Additional radiographic analysis of surgical COR was based on established techniques superimposing pre- and postoperative images. Position of the COR was defined in a rectangular net layered onto the osteotomy vertebrae (OVs). RESULTS The study included 34 patients undergoing PSO and 35 undergoing VCR, with mean ages of 57 and 29 years and mean RKA corrections of 31° and 49°, respectively. In the PSO group, COR was mainly in the anterior column, and surgical and conceptual COR matched in 22 patients (65%). Smaller RKA correction (27° vs 32°, p = 0.09) was seen in patients with anterior eccentric COR. Patients with rigid osteotomy sites were more likely to have an anterior eccentric COR (41% vs 11%, p = 0.05). In the VCR group, 20 patients (57%) had single-level VCR and 15 (43%) had multilevel VCR. COR was mainly located in the anterior or middle column. Mismatch between surgical and conceptual COR occurred in 24 (69%) patients. Larger RKA correction (63° vs 45°, p = 0.03) was seen in patients with anterior column COR. Patients with any posterior COR had a smaller RKA correction compared to the rest of the patients (42° vs 61°, p = 0.007). CONCLUSIONS Matching the surgical with the conceptual COR is difficult and in this study failed in one- to two-thirds of all patients. In order to avoid ST during correction of severe deformities, temporary rods, tracking rods, or special instruments should be used for correction maneuvers.

The rehabilitation of facial esthetics when transitioning from a failing dentition in a patient with maxillary protrusion is challenging. This clinical report described such a patient treated with an immediate cross-arch implant-supported fixed prosthesis. The ideal virtual upper lip position was used to predict the sagittal and vertical position of the restoration. A stackable device was fabricated to guide the osteotomy and implant placement.

Recent studies have reported that confined high-intensity and diffuse low-intensity on sagittal T2-weighted magnetic resonance imaging (MRI) are distinctive features that are highly predictive of delayed union or nonunion on osteoporotic vertebral fracture (OVF). The objective of this study was to identify the characteristics of imaging findings predicting the risk for requiring surgical treatment in fresh OVF with poor prognostic features on MRI.We conducted a retrospective study of 74 patients (17 men and 57 women with a mean age of 81.1 years) of OVF with the poor prognostic MRI findings. We compared the imaging findings between the surgery group (16 patients) and the conservative group (58 patients): vertebral instability defined as the difference between the vertebral collapse ratio in dynamic X-rays, and the grade of posterior wall injury (Grade I, no spinal canal encroachment; Grade II,2 mm; Grade III, ≥2 mm) as well as the presence or absence of pedicle fracture (Grade I, none; Grade II, unilateral; Grade III, bilateral) on computed tomography.The mean vertebral instability was 24.0% ± 10.1% in the surgery group and 13.0% ± 7.8% in the conservative group, which was significantly different. Posterior wall injury in the surgery and conservative groups was Grade I in 0 and 29 cases, Grade II in 5 and 21 cases, and Grade III in 11 and 8 cases, respectively, constituting a significant difference. Pedicle fracture in the surgery and conservative groups was Grade I in 5 and 55 cases, Grade II in 6 and 2 cases, and Grade III in 5 and 1 case, respectively, also constituting a significant difference.The most high-risk OVF patients with poor prognostic MRI findings who required surgical treatment were those who exhibited greater vertebral instability as well as either more severe posterior wall injury or pedicle fracture.Retrospective clinical study.

PurposeThe indications for surgery in patients with acute closed sagittal band injuries are still undetermined. The purpose of this study was to classify the types of injuries based on intraoperative findings of patients who underwent surgery for sagittal injuries, and to present the treatment plans and surgical methods.MethodsTwenty-five patients who had undergone surgical exploration for closed sagittal band injuries between January 2011 and December 2020 were included in the study, comprising 17 patients with acute injuries (within 3 weeks), four patients with chronic injuries, and four patients who underwent surgery because symptoms did not improve in response to conservative treatment. Patients with laceration, fracture, and rheumatoid arthritis were excluded.ResultsSagittal band injuries were classified into two groups: superficial sagittal band (SSB) and proper sagittal band (PSB) injuries. SSB injuries were observed in 75.0% of spontaneous rupture cases and PSB injuries were observed in 66.7% of traumatic rupture cases. SSB injuries were observed in 83.3% of Rayan and Murray classification type II cases and PSB injuries were observed in 61.5% of type III cases (p=0.041). PSB injuries were present in all four patients who underwent surgery because conservative treatment failed.ConclusionWe successfully corrected sagittal band injuries with extensor digitorum communis tendon instability through surgical treatment. Sagittal band injuries can be classified into two types depending on the anatomical injury pattern; SSB and PSB injuries. The surgical method and treatment plan can be chosen based on this classification.

Objectives The posterolateral approach to the distal tibia is commonly used for stabilisation of ankle fractures as it allows good visualisation and direct reduction of the posterior distal tibia and malleolar fragments. This approach can also be used for internal fixation of an associated lateral malleolus fracture. The aim of our study is to describe the surgical anatomy of the peroneal artery (PA) in relation to the tibial plafond and the distal fibula; thereby suggesting a safe zone during proximal dissection of posterolateral approach. Methods Using Computed Tomography Angiographic (CTA) study, the course of the PA in relation to the tibial plafond and distal fibula was analysed in 142 lower limbs (bilateral limbs of 71 adult patients; 43 males and 28 females). Axial, coronal, and sagittal CT sections were cross-linked to specify the position of the PA. The PA course was identified and the level of its distal bifurcation over the tibia was marked. Perpendicular measurements were made from this point to the tibial plafond and tip of distal fibula. Results The PA bifurcated distally at mean 58.3±24.2mm (SD) (range: 37.0–115.0mm) proximal to the right tibial plafond and mean 81.9±24.4mm (range: 54.0–137.0mm) from the right distal fibular tip. In the contralateral side, the PA bifurcated at mean 57.9±23.3mm (range: 36.0–125.0mm) proximal to the left tibial plafond and 81.8±23.9mm (range: 54.0–147.0mm) from the left distal fibular tip. The difference between the right and the left side of distal bifurcation point diameter of the same patient was assessed, range (0.0–58.0mm) with median 2.0mm and IQR 10.0mm. Three different PA vasculature patterns were identified. Conclusions It is important for surgeons to be aware of the surgical anatomy of PA to avoid inadvertent injury during posterolateral approach to distal tibia. The PA may bifurcate as close as 36mm from the tibial plafond with possible variation bilaterally. Therefore, special attention needs to be considered by the operating surgeon while dissecting in this region due to the wide anatomical variation in vasculature. However, once the PA is mobilised, any fixation modality including posterior buttress plate could be safely performed.

Study Design: This is a descriptive observational study.Purpose: The objective of this study is to analyze and document the sagittal alignment of the spine and pelvis in normal Indian adult volunteers and compare these parameters with the study population of other races and ethnicities.Overview of Literature: Given the importance of the spinopelvic parameters, there is a need to describe the parameters differentially in relation to the ethnicity of the studied individual. Very few reports have defined the normal physiological value. Ethnic differences are a significant factor not only when describing the anthropometric data but also when applying the findings to a different ethnic group. We have compared these values with other races and ethnicities so that we can know whether the principles of spinal fixation can be applied globally.Methods: In total, 100 participants were studied by using their anteroposterior and lateral radiographic images of whole of pelvic and spinal area. Additionally, various spinal and pelvic parameters were also measured. Subsequently, the outcomes were analyzed with respect to age, sex, and body mass index (BMI). The correlation between different parameters and differences in these parameters between Indians and other races/ethnicities along with population groups were also analyzed. Results: There was a significant increase in thoracic kyphosis (TK) from T1–T12 and T4–T12 with increasing age. Lumbar lordosis (LL), sacral translation (sagittal vertical axis), and pelvic tilt were significantly higher among females. Additionally, sacral slope (SS), pelvic incidence, C7 sagittal offset, and T9 sagittal offset were also higher in females. TK (T4–T12 and T1–T12), LL, SS, and pelvic incidence showed a significant correlation with BMI. As compared to European population, TK, segmental LL, and sacral translation were found to be significantly lesser in Indian population.Conclusions: There is a statistically significant difference between Indians and other races/ethnicities and population groups with respect to TK, LL, and sacral translation. The values obtained can be considered as the physiological normal values for Indian population. Importantly, these values can serve as the reference values for future studies.

About 1% of the newborn population has developmental dysplasia of the hip (DDH), altering joint biomechanics, gait performance and balance control. Pemberton's osteotomy is used in early treatment but it remains unclear whether it will help the patient regain normal balance control during gait. The current study aimed to identify the changes of the whole-body balance control during level walking in children treated for unilateral DDH during toddlerhood, in terms of inclination angles (IA) of the line joining the body's center of mass (COM) and center of pressure (COP), and the rate of change of IA (RCIA).Twelve girls (DDH group; age: 7.1 ± 2.1 years) who had been treated with Pemberton's osteotomy for unilateral DDH during toddlerhood and twelve healthy controls (Control group; age: 7.6 ± 2.1 years) walked at their preferred walking speed while IA, RCIA and temporal-spatial parameters were calculated from measured kinematic and forceplate data, and were compared using independent t-tests.Compared to the Control group, the DDH group showed significantly decreased sagittal IA (p = 0.042) but increased range of sagittal RCIA during SLS on the unaffected side (p = 0.006), and increased peak sagittal RCIA during DLS (p 0.008). In the frontal plane, the altered COM-COP control occurred mainly during stance phase of the affected side, showing a decreased range of RCIA during SLS (p = 0.033) followed by decreased IA (p = 0.045) with an increased peak value of RCIA (p = 0.023) during terminal DLS.The children with treated unilateral DDH showed compromised, bilaterally different balance control strategies with altered COM-COP control during gait, not only during stance in the frontal plane as expected, but even more so during swing in the sagittal plane. It is thus suggested that routine assessment of the morphological changes and/or altered balance control of both the unaffected and affected hips is equally important for early identification of any signs of insidious hip problems, deteriorating balance control or increased risk of loss of balance.

Background Pathological gait patterns are common in neurological and orthopedic patients. These put them at risk of falling and restrict their autonomy and social participation. Novel assistive walking devices are designed to actively support physiological gait patterns by means of motor guidance and mechanical support of the lower limbs. Research question Does a non-electric assistive walking device powered by a cam-spring mechanism (aLQ, Imasen) improve or otherwise affect pathological gait patterns in neurological and orthopedic patients? Methods A three-dimensional instrumented gait analysis was conducted on a treadmill (quasar, hp cosmos) using spatiotemporal, kinetic, and kinematic data obtained from synchronized motion capturing (Miqus M3, Qualisys), surface EMG (sEMG; Ultium, Noraxon), and pressure distribution measurements (FMD-T, Zebris). Participants with impaired walking were tested in a randomized repeated measures design (assisted/unassisted; at preferred/fast speed) and analyzed with regard to their medical condition (orthopedic or neurological group, n=20 each). Results In both groups, participants showed a significant increase of step length and decrease of cadence during assisted walking compared to baseline. Immediate kinematic effects included enhanced sagittal hip flexion but reduced extension. On the contrary, knee joint angles and muscle activity of M. gastrocnemius and M. rectus femoris seemed to be unaffected by the aLQ device. Significance Participants appear to benefit from the assistive walking device regarding gait and movement patterns, which suggests that the tested device may help to improve patients’ functional health status and quality of life. Activities of daily living (ADLs) that involve extensive hip flexion like stairs or curb climbing are promising applications. We propose the implementation of an invertible cam-spring that provides an additional resistance training option.

Introduction Deformity associating coronal and sagittal malalignment can severely impair quality of life in Parkinson's disease (PD). Realignment using patient-specific rods (PSRs) is useful for achieving alignment goals. Methods This was a retrospective single-center analysis of a prospectively maintained database of all PD patients who underwent surgery between January 2013 and January 2017. Clinical evaluation, preoperatively and at 1 year's follow-up, used the Oswestry Disability Index (ODI). Radiological evaluation used systematic preoperative and 1-year postoperative full-spine radiographs. Results Twelve patients were included: 6 female, 6 male; mean age, 68.4 years. Mean follow-up was 40.8 months [range 12–70]. On average, 14 levels were fused [range 10–18]. Unplanned revision surgery was necessary for 8 patients at a mean 15.625 months after index surgery. Mean preoperative ODI score was 64% preoperatively [range 56–70] versus 52% [range 28–64] at 1 year's follow-up (P = 0.004). Lumbar lordosis improved significantly, from −16.7° preoperatively to −41.4° at 1 year (P = 0.006). Pelvic tilt was the least effectively corrected parameter, with a mean preoperative value of 31.6° vs. 27.8° at 1 year (P = 0.19). Mean preoperative sagittal vertical axis was 149.7 mm versus 73.6 mm at 1 year (P = 0.013). Mean preoperative coronal tilt was 68.2 mm versus 22.9 mm at 1 year (P = 0.007). Conclusion Parkinson's disease is a degenerative disease frequently associated with major spine malalignment. The severity of the postural disorders in these patients needs special precautions to avoid complications.

Introduction: Brain tumor is among the major causes of morbidity and mortality rates worldwide. According to National Brain Tumor Foundation (NBTS), the death rate has nearly increased by as much as 300% over last couple of decades. Tumors can be categorized as benign (non-cancerous) and malignant (cancerous). The type of the brain tumor significantly depends on various factors like the site of its occurrence, its shape, the age of the subject etc. On the other hand, Computer Aided Detection (CAD) has been improving significantly in recent times. The concept, design and implementation of these systems ascend from fairly simple ones to computationally intense ones. For efficient and effective diagnosis and treatment plans in brain tumor studies, it is imperative that an abnormality is detected at an early stage as it provides a little more time for medical professionals to respond. The early detection of diseases has predominantly been possible because of medical imaging techniques developed from past many decades like CT, MRI, PET, SPECT, FMRI etc. The detection of brain tumors however, has always been a challenging task because of the complex structure of the brain, diverse tumor sizes and locations in the brain. Method: This paper proposes an algorithm that can detect the brain tumors in the presence of the Radio-Frequency (RF) inhomoginiety. The algorithm utilizes the Mid Sagittal Plane as a landmark point across which the asymmetry between the two brain hemispheres is estimated using various intensity and texture based parameters. Result: The results show the efficacy of the proposed method for the detection of the brain tumors with an acceptable detection rate. Conclusion: In this paper, we have calculated three textural features from the two hemispheres of the brain viz: Contrast (CON), Entropy (ENT) and Homogeneity (HOM) and three parameters viz: Root Mean Square Error (RMSE), Correlation Co-efficient (CC), and Integral of Absolute Difference (IAD) from the intensity distribution profiles of the two brain hemispheres to predict any presence of the pathology. First a Mid Sagittal Plane (MSP) is obtained on the Magnetic Resonance Images that virtually divides brain into two bilaterally symmetric hemispheres. The block wise texture asymmetry is estimated for these hemispheres using the above 6 parameters.

Cycling has grown in popularity over the past 20 to 30 years, serving as transportation, fitness, and sport. Cycling is unique for several reasons: it is a non-weight-bearing sport, nearly all of the motion is in the sagittal plane, and it is one of the only sports where an individual remains attached to a machine for a long duration. As such, the cycling athlete has unique needs compared with other endurance-based athletes. The complex biomechanical interaction of bicycle and rider requires a systematic process for assessment, which provides the framework for understanding, evaluating, and treating overuse injury in cyclists.

The foot arch plays an important role in propulsion and shock absorption during walking and running; however, the relationship among the foot arch, metatarsal locking theory, and nature of the windlass mechanism (WM) remain unclear.What are the differences in the kinematic relationship between the foot arch, hindfoot, and hallux during walking and running?Relative angles within the foot were measured in 18 healthy men using the Oxford foot model (OFM). Data for barefoot walking at a comfortable speed and rearfoot running at 2.0 m/s were collected. Angles of the forefoot relative to the hindfoot (OFM-arch), hallux relative to the forefoot (Hallux) on the sagittal plane, and hindfoot relative to the shank (Hindfoot) on three anatomical planes were obtained. The medial longitudinal arch (MLA) angle was calculated to verify that OFM-arch can substitute the MLA angle. Each parameter was subjected to cross-correlation analysis and Wilcoxon signed-rank tests to examine the relationship with OFM-arch and compare them during walking and running.OFM-arch was similar to the conventional MLA projection angle in both trials (gait: 0.79, running: 0.96 p 0.01). Synchronization of the OFM-arch and Hallux angles was higher in running than in walking (gait: -0.09, running: -0.75 p 0.01). Hindfoot supination was unrelated to OFM-arch. Hindfoot angle on the transverse plane exhibited a moderate relationship with OFM-arch, indicating different correlations in walking and running (gait: 0.63, running: -0.68 p 0.01).The elevation of the foot arch due to hallux dorsiflexion differed during walking and running; hence, other factors besides WM (such as intrinsic muscles) may affect the foot arch elevation during running. The hindfoot in the frontal plane does not contribute to arch raising and foot stability during running; it features different relationships with OFM-arch during walking and running.

We evaluated the effects of using a navigation technique with anterior approach surgery for thoracolumbar burst fractures on vertebral body screw placement and discussed its effects on the long-term prognosis of patients.We performed a prospective study of patients who had undergone anterior approach thoracolumbar surgery from May 2018 to August 2019. The 40 patients were randomly divided into the navigation group (NG) and control group (CG). In the NG, vertebral body screw placement was performed with 2-dimensional navigation guidance. For the CG, no navigation guidance was used. The clinical and radiological evaluations of the 2 groups were compared preoperatively, immediately after surgery, and at the final follow-up. Paired t tests and the χNo differences were found in the hospital stay, operation time, autologous blood recovery, postoperative drainage volume, Cobb angle of the preoperative coronal plane and sagittal plane, postoperative sagittal plane, postoperative Cobb angle of the coronal and sagittal planes measured on radiographs and computed tomography scans between the 2 groups (P0.05). The correction of the kyphosis deformity of the fracture segment was better in both groups (P0.001). The intraoperative blood loss and Cobb angle of the postoperative coronal plane in the NG was less than that in the CG (P0.05). Also, the 4 vertebral body screws in the NG were more parallel to the endplate than were those in the CG.We found that the use of navigation can improve the accuracy of screw placement in anterior approach surgery for thoracolumbar burst fractures and improve patients' long-term prognosis.

Purpose To investigate the spinopelvic alignment and vertebral shape in children, and associations with body composition and structural spinal abnormalities on magnetic resonance imaging (MRI). Methods We performed a cross-sectional study embedded in the Generation R Study, a prospective population-based birth cohort. Pelvic incidence and vertebral concavity ratios for each lumbar level were determined on sagittal MRI images in 9-year-old children, and structural spinal abnormalities were scored semi-quantitatively. The BMI-SD score was calculated, and body composition was assessed using DXA scans. Associations of pelvic incidence and vertebral concavity ratios with structural abnormalities and body composition measures were assessed using (multilevel) regression analyses. Results This study included 522 participants (47.7% boys), aged 9.9 years (IQR 9.7–10.0). The mean pelvic incidence was 36.6° (SD 8.0). Vertebral concavity ratios ranged from 0.87 to 0.90, with significantly lower ratios for boys compared to girls. Associations were found for a larger pelvic incidence with decreased disc height [OR 1.03 (95% CI 1.02–1.05)], and a pelvic incidence in the lowest tertile with less disc bulging [OR 0.73 (95% CI 0.56–0.95)]. Increased vertebral concavity ratio was associated with decreased disc height [OR 14.16 (95% CI 1.28–157.13)]. Finally, increased fat-free mass index was associated with a smaller pelvic incidence [adjusted OR 0.85 (95% CI 0.07–1.63)]. Conclusion The mean pelvic incidence of 9-year-old children is 36.6° on supine MRI images, and a slightly concave shape of the lumbar vertebrae is seen. Spinopelvic alignment is associated with structural spinal abnormalities, and might itself be influenced by the children’s body composition.

Objectives Considering sagittal balance is particularly important in ASD patients because they frequently show hypolordotic prior fusion. Therefore, the purpose of this study was to identify risk factors for aggravation of sagittal imbalance after posterior lumbar fusion in ASD patients. Methods Fifty-nine patients who underwent revision posterior surgery for ASD between 2014 and 2018 were included. Patients were divided into two groups according to postoperative sagittal balance status determined by the pelvic incidence minus lumbar lordosis (PI-LL) value, based on the age-adjusted Schwab classification (group A: ideal correction, N = 20; group B: undercorrection, N = 39). Several radiographic parameters were measured in plain radiographs. Clinical results were analysed using the visual analog scale, Oswestry Disability Index, and EuroQol 5-domain. Results Better preoperative PI-LL (p = 0.001), slippage of the vertebral body (p = 0.022), higher disc height (p = 0.048), and absence of L4-5-S1 fusion (p = 0.041) in the index surgery were significantly correlated with better postoperative sagittal balance in multivariate analysis. The PI-LL improved postoperatively from 19.4 to 12.5 in group A (p = 0.019) and remained unchanged (from 38.6 to 38.6, p = 1.000) in group B. Although clinical outcomes improved postoperatively in both groups, no inter-group differences were observed. Conclusions Preoperative sagittal imbalance, rigid affected segments, and previously fused lower lumbar segment (L4-5-S1) are independent risk factors for aggravation of sagittal imbalance in ASD patients. Surgeons should strive to restore sagittal balance after ASD surgery under the above-mentioned conditions.

This study aims to introduce a new sagittal cephalometric measurement, the sagittal G-triangle analysis, to accurately and reproducibly assess the sagittal jaw relationship. Sagittal G-triangle analysis, which consists of angles AXK and BXK, is based on an equilateral triangle (Bo-X-K) constructed using 5 cephalometric landmarks (Ba, Bo, Po, Or, and G). To test the diagnostic efficiency of this analysis, pretreatment cephalometric radiographs of 120 female and 120 male Chinese patients were randomly selected. For each enlisted subject, angles SNA and SNB as well as angles AXK and BXK were measured and recorded. On the basis of the SNA and SNB results, subjects were categorized into 6 groups: maxillary retrognathism, normal maxilla, maxillary prognathism, mandibular retrognathism, normal mandible, and mandibular prognathism. The diagnostic efficiency of angles AXK and BXK were evaluated using various statistical tests. A high correlation was detected between angles SNA and AXK as well as between angles SNB and BXK. Female patients with angle AXK between -2.255° and 2.860° and male patients with angle AXK between -2.615° and 2.120° were considered to have a normal maxilla position. Female patients with angle BXK between -2.61° and 2.93° and male patients with angle BXK between -2.275° and 0.610° were considered to have a normal mandible position. In conclusion, sagittal G-triangle analysis could be used as an alternative method for the evaluation of the sagittal position of the maxilla and mandible in cephalometric analysis.

BACKGROUND: The lower back is the most common injury location in pole vaulters, but the prevalence of lumbar spondylolysis and intervertebral disc degeneration is not known. OBJECTIVE: This study aimed to determine the prevalence of lumbar spondylolysis and intervertebral disc degeneration in pole vaulters. METHODS: This cross-sectional study was conducted in the Tokai area of Japan and included 21 pole vaulters (mean ± standard deviation [range]: age, 22.2 ± 3.2 [18–28] years; height, 172.2 ± 4.7 [165.0–182.0] cm; body weight, 67.6 ± 7.3 [54.0– 80.0] kg). The majority of pole vaulters were collegiate athletes. We performed anterior, lateral, and oblique radiography at 45∘ and magnetic resonance imaging in the sagittal and coronal planes of the lumbar spine. The evaluation was performed independently of whether the athletes had lower back pain (LBP). Moreover, we investigated the duration of pole-vaulting experience and history and current presence of LBP using a questionnaire. RESULTS: The prevalence of lumbar spondylolysis and intervertebral disc degeneration was 28.6% (6/21) and 38.1% (8/21), respectively. Herniation was found in six discs in four vaulters (19.0%). All athletes had a history of LBP. The prevalence of lumbar spondylolysis was high (28.6%). CONCLUSIONS: Sport-specific movements performed by pole vaulters may be a risk factor for lumbar spondylolysis.

Background/purpose Review of literature, evaluation of the styloid process (SP) using cone beam computed tomography (CBCT) has not been performed in a Taiwanese population. Our study aimed to evaluate the different characteristics of SP using CBCT in a Taiwanese population. Materials and methods CBCT scans of 121 patients (55 males, 66 females; mean age, 27 ± 9.09 years) were evaluated to assess the length, morphological type, calcification pattern, and angulation of the SP. A SP length greater than or equal to 30.00 mm is considered to indicate an elongated SP (ESP). ESP was classified in terms of morphology as Type I: uninterrupted; Type II: pseudo-articulated; or Type III: segmented. The calcification pattern of SP was categorized as Type A: calcified outline; Type B: partially calcified; Type C: nodular; or Type D: completely calcified. The transverse and sagittal angles between the bilateral SP were also measured. Results One-hundred and nine patients had a bilateral SP and 12 patients had a unilateral SP. The mean SP length was 26.34 ± 7.44 mm. Forty-two (34.71%) patients had an ESP. The most common ESP morphology was Type 1, followed by Type II, then Type III, while the calcification pattern prevalence was of the descending order Type B, Type A, Type C, and Type D. The mean transverse and sagittal angles were 66.90 ± 5.41° and 26.67° ± 6.50°, respectively. Conclusion The present study was the first to evaluate the characteristics of SP in a Taiwanese population using CBCT. The data contribute a useful basis for clinical investigation of the SP in future.

Background The freezing episode (FE) management during gait in Parkinson's disease is inefficient with current medications, neurosurgery, and physical interventions. Knowing the biomechanical change patients suffer preceding FE would be the ultimate goal to measure, predict, and prevent these events. Objective We performed a systematic review to summarize the kinematic, kinetic, electromyographic, and spatio-temporal characteristics of the events that precede the FE during gait in Parkinson's disease. Literature Survey Databases searched included PubMed, Embase, and Cochrane and between 2001 to August 2021. Methodology The present study was a systematic review registered in the PROSPERO database (CRD42021255082). Three reviewers searched and selected studies with methodologies involving biomechanical changes and kinetic, kinematic, electromyography, and spatiotemporal changes before FE in a patient with Parkinson's disease. The relevant articles that show the events preceding FE in patients with PD were identified. We excluded studies that describe or compare methods or algorithms to detect FE. Studies may include participants with all PD severity, time of disease, and age. Synthesis We selected ten articles for final evaluation. The most consistent results indicate a dramatic reduction of movement excursions with (1) decrease in stride length; (2) decreased gait speed; (3) postural instability with the increased double support phase; (4) incoordination of anterior tibial and gastrocnemius; (5) larger amplitude in the EMG of biceps femoris; (6) decreased range of motion in the sagittal plane at the ankle and hip joints; and (7) anterior pelvic tilt. Conclusion FE is characterized by complex motor patterns than normal gait and mismatched gains in the perception and execution of the ongoing movement.

Rat-robots show great potential for rescue and search applications in very tight spaces because of their excellent mobility and environmental adaptability. However, owing to the complexity of the working environment, there is currently no effective localization method. In this study, we present a novel rat-robot localization system based on dead reckoning. A wearable exoskeleton was used to measure the trajectories of the rat-robot’s two hindlimb ankle joints. A relational model was established to estimate the step length from the horizontal distance between the two ankle joints in the sagittal plane, and an inertial sensor obtained the heading of the rat-robot in the navigation coordinate system. The proposed system was tested by both the one-dimensional and two-dimensional locomotion experiment. The step length estimation error of our system was 0.6 ± 3.1%, and the positioning estimation error in the two-dimensional space was 1.65 ± 1.06%. These experimental results demonstrate the efficacy of this system in providing accurate distance and position estimation for the rat-robot.

Background The scalpel sign is a radiological finding observed on sagittal magnetic resonance imaging and computed tomography myelography corresponding to an indentation in the dorsal aspect of the spinal cord resembling a surgical scalpel blade. It is said to be a pathognomonic imaging discovery linked to dorsal arachnoid webs. However, other spine-related conditions may mimic dorsal arachnoid webs on magnetic resonance imaging, such as spinal arachnoid cysts or ventral spinal cord herniation, leading to misdiagnosis. Methods A retrospective review was performed of cases involving 3 different diagnoses at our institution in the last 5 years that shared in common the characteristic focal dorsal indentation of the spinal cord. Results Of 7 cases identified, all but 1 were treated and confirmed intraoperatively. All lesions were located at the dorsal spinal cord. Magnetic resonance imaging was the study of choice for evaluation. Clinical manifestations included back pain and lower extremity numbness and weakness together with compressive myelopathy signs and urinary symptoms. Mean follow-up was 16.8 months with satisfactory postoperative results. Conclusions Isolated radiological presentation of the scalpel sign is not sufficient to distinguish between dorsal arachnoid webs, arachnoid cysts, and ventral herniation of the spine. However, awareness of its importance is relevant for accurate curative surgical planning.

Background: Segment coordination variability (CV) is a movement pattern associated with running-related injuries. It can also be adversely affected by a prolonged run. However, research on this topic is currently limited. The purpose of this study was to investigate the effects of a prolonged run on segment CV and vertical loading rates during a treadmill half marathon. Methods: Fifteen healthy runners ran a half marathon on an instrumental treadmill in a biomechanical laboratory. Synchronized kinematic and kinetic data were collected every 2 km (from 2 km until 20 km), and the data were processed by musculoskeletal modeling. Segment CVs were computed from the angle-angle plots of selected pelvis-thigh, thigh-shank, and shank-rearfoot couplings using a modified vector coding technique. The loading rate of vertical ground reaction force was also calculated. A one-way MANOVA with repeated measures was performed on each of the outcome variables to examine the main effect of running mileage. Results: Significant effects of running mileage were found on segment CVs (p ≤ 0.010) but not on loading rate (p = 0.881). Notably, during the early stance phase, the CV of pelvis frontal vs. thigh frontal was significantly increased at 20 km compared with the CV at 8 km (g = 0.59, p = 0.022). The CV of shank transverse vs. rearfoot frontal decreased from 2 km to 8 km (g = 0.30, p = 0.020) but then significantly increased at both 18 km (g = 0.05, p < 0.001) and 20 km (g = 0.36, p < 0.001). Conclusion: At the early stance, runners maintained stable CVs on the sagittal plane, which could explain the unchanged loading rate throughout the half marathon. However, increased CVs on the frontal/transverse plane may be an early sign of fatigue and indicative of possible injury risk. Further studies are necessary for conclusive statements in this regard.

The ability to dynamically reintegrate proprioceptive signals after they have been perturbated is impaired in certain pathologies. Evaluation of proprioceptive reintegration is useful for clinical practice but currently requires expensive laboratory tools. We developed a simple method, accessible to clinicians.Is two-dimensional (2D) video analysis of earlobe displacement a valid and reliable tool for the evaluation of ankle proprioceptive reintegration following muscle vibration?Thirty-eight healthy individuals underwent vibration of the triceps surae while standing on a force plate (FP). Anterior (sagittal plane) earlobe displacement ('overshoot') was recorded at vibration cessation using 2D video analysis and rated by 3 blind examiners. Correlation analysis was performed between earlobe and center of pressure displacement (dCoP, recorded with the FP) to determine validity. Intra and interrater reliability were determined by calculation of the intraclass correlation coefficient (ICC), change in the mean (CiM), standard error of measurement (SEM) and the minimal detectable change (MDC).Strong positive correlations (r = 0.82-0.94, p .001) were found between video and FP data. Intra- and interrater reliability were excellent (ICC from 0.99 to 1.00 and from 0.90 to 0.97 respectively). For intrarater analysis, the CiM was 0.01 cm, SEM were 0.27 cm (95% CI: 0.23-0.33) and 3.43% (95% CI: 2.92-4.20) and the MDC was 0.74 cm. For interrater reliability, the CiM ranged from - 0.81-0.55 cm, the SEM from 0.61 to 1.12 cm and the MDC from 1.69 to 3.10 cm. 2D video analysis of anterior (sagittal) earlobe displacement is therefore a valid and reliable method to assess postural recovery following muscle vibration. This simple method could be used by clinicians to evaluate the ability of the central nervous system to reintegrate proprioceptive signals from the ankle. Further studies are needed to assess its validity in individuals with proprioceptive impairment.

OBJECTIVE To investigate influences of spinopelvic parameters, such as lumbar lordosis (LL) angles, pelvic incidence, sacral slope, pelvic tilt, and sagittal vertical axis, on development of the proximal junctional failure fracture type after posterior instrumentation. METHODS This retrospective 1:3 matched case-control cohort study included 24 patients who developed proximal instrumented fracture in the study group and 72 patients without proximal junctional failure in the control group. Weighted Charlson Comorbidity Index and bone mineral density with T-score were recorded. In addition to spinopelvic parameters, proximal local kyphosis (PLK), which refers to a kyphosis angle between the upper end plate of upper instrumented vertebra plus 1 level and the lower end plate of upper instrumented vertebra; pelvic incidence-LL mismatch; and spinopelvic realignment score were calculated. RESULTS More comorbidities (Charlson Comorbidity Index, P = 0.002) and poorer bone density (T-score, P = 0.001) were noted in the study group. Before surgery, the study group had significantly lower LL (P = 0.046) and sacral slope (P = 0.043) and significantly higher PLK (P < 0.001) and pelvic tilt (P = 0.044) than the control group. Postoperatively, the study group had significantly higher PLK (P < 0.001) and lower LL (P = 0.031) than the control group; the degree of pelvic incidence-LL mismatch (P = 0.007) remained significantly higher in the study group. Preoperative (P = 0.026) and postoperative (P = 0.045) spinopelvic realignment scores was worse in the study group. Multivariate analysis revealed that postoperative PLK was the most significant radiographic factor to predict proximal instrumented fracture (P = 0.002, odds ratio 1.140, 95% confidence interval). CONCLUSIONS In our experience, appropriate LL and lower PLK should be obtained at surgery to prevent development of instrumented fracture.