Anteroposterior Displacement Research Articles

Estimating whole-body centre of mass sway during quiet standing with inertial measurement units.

Our ability to balance upright provides a stable platform to perform daily activities. Balance deficits associated with various clinical conditions may affect activities of daily living, highlighting the importance of quantifying standing balance in ecological environments. Although typically performed in laboratory settings, the growing availability of low-cost inertial measurement units (IMUs) allows the assessment of balance in the real world. However, it is unclear how many IMUs are required to adequately estimate linear displacements of the centre of mass (CoM) at stance widths associated with daily activities. While wearing IMUs on their head, sternum, back, right thigh, right shank, and left shank, 16 participants stood quietly on a force platform in narrow, hip-width, and shoulder-width stances, each for three two-minute trials. Using a multi-segment biomechanical model, we estimated CoM displacements from all possible combinations of the IMUs. We then calculated the correlation between the IMU- and force platform- CoM estimates to determine the minimal number of IMUs needed to estimate CoM sway. Four IMUs were necessary to accurately estimate anteroposterior (AP) and mediolateral (ML) CoM displacements across stance widths. Using IMUs on the back, right thigh, and both shanks, we found strong correlations between the IMU CoM estimation and the force platform CoM estimation in narrow stance (AP: r = 0.92±0.04, RMSE = 2.39±2.08 mm; ML: r = 0.97±0.02, RMSE = 1.16±0.77 mm), hip-width stance (AP: r = 0.93±0.04, RMSE = 2.00±1.18 mm; ML: r = 0.92±0.06, RMSE = 0.92±0.70 mm), and shoulder-width stance (AP: r = 0.93±0.03, RMSE = 1.95±1.66 mm; ML: r = 0.86±0.13, RMSE = 1.39±1.46 mm). These results indicate that IMUs can be used to estimate CoM displacements during quiet standing and that four IMUs are necessary to do so. Using an algorithm based on a simple biomechanical model, researchers and clinicians can estimate whole-body CoM displacements accurately during unperturbed quiet standing. This approach can improve the ecological validity of standing balance research and opens the possibility for assessing/monitoring patients with standing balance deficits.

Significant differences in knee kinematics of healthy subjects with high and low anterior tibial laxity

BackgroundAnterior tibial laxity is considered to be a risk factor for knee injuries, including anterior cruciate ligament ruptures. The anterior cruciate ligament reconstruction also aims to restore anterior tibial laxity. While anterior tibial laxity is considered to be linked to dynamic knee stability, the mechanisms connecting anterior tibial laxity to these stability issues are not fully understood. The purpose of this study was to investigate the kinematic alterations between different anterior tibial laxity in healthy subjects. We hypothesized that anterior tibial laxity affects the anteroposterior tibial displacement during dynamic movements.MethodsThis study involved thirty-five healthy subjects. There were twenty males and fifteen females with an average age of 18.91 ± 0.78 years. Their knees were categorized into “Tight” (the smallest 50%) and “Lax” (the largest 50%) groups based on anterior tibial laxity measurements using a Kneelax3 arthrometer. Kinematic data were collected using a three-dimensional motion capture system when they performed level walking, upslope walking, and vertical jumping. The knee kinematics were recorded for statistical analysis. We used independent sample t-tests to analyze key kinematic differences between groups.ResultsThe “Lax” group exhibited increased posterior tibial translation during upslope walking (5.4 ± 2.22 mm at swing max flexion, p = 0.018) and vertical jumping (8.5 ± 2.78 mm at propulsion max flexion, p = 0.003; 7.6 ± 3.17 mm at landing max flexion, p = 0.019) than the “Tight” group. Significant differences in tibial internal rotation were observed during initial contact of the gait cycle of level walking (1.9° ± 0.95°, p = 0.049) and upslope walking (2.1° ± 1.03°, p = 0.041) in the “Lax” group compared to the “Tight” group. No significant differences in adduction/abduction or medial/lateral tibial translation were found between groups.ConclusionThe study revealed that high anterior tibial laxity resulted in increased posterior tibial translation and tibial internal rotation. High anterior tibial laxity resulted in dynamic instability of knees during motions, especially in high-demanding activities like upslope or vertical jumping. However, further research is needed to explore the clinical functional effects of knee laxity.

A Potential Mechanism Involved in the Regularity of Center-of-Pressure Displacements During Achieving Unipedal Equilibrium on Stable and Unstable Surfaces.

Sample entropy (SampEn) is a widely used measure for estimating the regularity of center-of-pressure (COP) trajectories, with high COP regularity (low SampEn) commonly interpreted as ineffective postural control. The current study aimed to investigate one possible source of COP regularity-agonist-antagonist coactivation-resulting in joint stiffness or action stability. A cross-correlation analysis was conducted to determine the similarity (coactivation) level of 5 pairs of lower limb agonist-antagonist electromyographic signals. SampEn was applied to anteroposterior (ap) and mediolateral (ml) COP displacements. Electromyographic and COP signals were simultaneously derived from 25 active young adults (25.6 ± 4.0years) during unipedal balancing on stable and multiaxial-unstable surfaces. Then, the correlation between individual agonist-antagonist cross-correlation coefficients and SampEn-COP was explored. The results show that only the tibialis anterior-peroneus longus (TA-PL) coactivations are negatively correlated with SampEn-COPap/ml (P ≤ .030) in both surface conditions, with greater TA-PL coactivation appearing with lower SampEn-COPap/ml. In addition, sex effects as one factor that might influence postural control were also tested. Women exhibited greater TA-PL coactivation (P = .017) and lower SampEn-COPap (P = .005) than men. Together, TA-PL coactivation could be one possible origin of COP regularity, but its effects might be detrimental to unipedal postural control, especially for women.

Efficacy of Foot Orthoses With Sensorimotor Bars on Gait, Postural Control, and Muscle Activity in Healthy Individuals and Those With Musculoskeletal Disorders: A Systematic Review

Objectives: The foot and ankle complex is crucial in stability, propulsion, and musculoskeletal interactions. Optimizing orthotic interventions in this anatomical region is essential to improve motor outcomes. This systematic review investigates the impact of foot orthoses (FOs) with sensorimotor bars on gait, postural control, and muscle activity in healthy individuals and those with musculoskeletal disorders. Methods: We conducted an electronic search in January 2024 using the PubMed, Web of Science, and Scopus databases. The article identification, screening, and selection followed the PISMA (the preferred reporting items for systematic reviews and meta-analysis) guidelines. We conducted the quality assessment using the PEDro (the physiotherapy evidence database) checklist. Data extraction and synthesis were performed using the Cochrane handbook for systematic review of interventions. Results: FOs with sensorimotor bars can increase foot external rotation, dorsiflexion, and abduction while decreasing foot eversion. Additionally, they can reduce anteroposterior displacement of the hip, shoulder, and head. Furthermore, significant improvements have been observed in spatiotemporal parameters such as walking speed, stride length, stance time, swing time, and kinetic parameters such as plantar pressure. These orthoses can also impact clinical tasks and decrease center-of-pressure movements. Discussion: Sensorimotor bars have demonstrated beneficial effects on gait (kinematic, kinetic, and spatial-temporal measures), balance control (clinical performance and center of pressure displacement measures), and muscle activity recording.

Postural Changes and Pain Levels in Patients with Unilateral Knee Injury

Introduction: Postural control is essential for balance and fall prevention but can be compromised by injuries such as anterior cruciate ligament (ACL) rupture and knee osteoarthritis (OA). ACL rupture affects proprioception and joint stability, while OA causes pain and stiffness, impacting mobility and muscle strength. The base of support, defined by the contact points of the body with the ground, is a crucial parameter in evaluating postural control. Objective: To assess changes in the base of support during bipedal postural control in young adults with complete ACL rupture and elderly individuals with unilateral knee osteoarthritis. Methodology: An observational and comparative study with 40 adults divided into two groups: G1 (elderly with unilateral knee osteoarthritis) and G2 (young adults with complete ACL rupture). The BaroScan® plantar pressure platform was used to collect data on the center of pressure (COP) and weight distribution. Pain perception was assessed using the Visual Analog Scale (VAS). Results: There was a significant difference in pain perception (VAS) between the groups (p = 0.04), with higher pain in G1. The mediolateral displacement of the COP (COPML) was also greater in G1 (p = 0.03). There was no significant difference in body weight distribution and anteroposterior displacement of the COP between the groups. Conclusion: Individuals with OA exhibit higher pain perception and greater mediolateral sway during postural control. Chronic pain and muscle strength loss may contribute to impaired postural control in the elderly with OA. In contrast, young individuals with ACL injuries may compensate for the injury with greater neuromuscular adaptation. Individual variability in response to pain and injury highlights the importance of personalized approaches in treatment and rehabilitation.

The most responsive foot position for non-invasive detection of isolated unstable syndesmotic injuries – a 3D analysis

BackgroundThe aim of this study was to identify the most responsive foot position for detection of isolated unstable syndesmotic injury.MethodsFourteen paired human cadaveric lower legs were positioned in a pressure-controlled radiolucent frame and loaded under 700 N. Computed tomography scans were performed in neutral position, 15° internal / external rotation, and 20° dorsal / plantar flexion of the foot before and after cutting all syndesmotic ligaments. For each position, generated 3D models of the intact and injured distal tibiofibular joints were matched and analyzed by calculating three parameters: diastasis, anteroposterior displacement, and shortening of the fibula.ResultsTransection of syndesmotic ligaments resulted in significant posterior translation of the fibula (4.34°, SD 1.63°, p < 0.01) compared to uninjured state for external rotation, significant anterior translation (-2.08°, SD 1.65°, p < 0.01) for internal rotation, and significant posterior translation (1.32°, SD 1.16°, p = 0.01) for dorsiflexion. Furthermore, the syndesmotic injury led to significantly increased clear space (0.46 mm, SD 0.46 mm, p = 0.03) in external rotation of the foot.ConclusionExternal rotation of the foot under loading seems to be the most responsive position for detection of isolated syndesmotic instability. Under external rotational stress, anteroposterior instability and increased clear space resulting from a complete isolated unstable syndesmotic lesion were most evident.

Reliability of the Wii balance board for static and dynamic balance assessment in total knee arthroplasty patients

PurposePoor performance in practicing balance tasks is partly caused by the changes in the knee function and balance control activities following total knee arthroplasty (TKA). The purpose of this study was to determine the test-retest reliability of the static and dynamic balance measures using Wii Balance Board (WBB) in patients after TKA. DesignThirty-one TKA patients (6 males, 27 females, mean age 55 ± 5.3 years) were involved in the study. They performed four standing balance trials on a WBB on two occasions, with an interval of 3–7 days apart. Double leg stance and functional reach task with opened and closed eyes were assessed in four trials. Extracted center of pressure (COP) measures collected included: mean velocity, medio-lateral displacement, antero-posterior displacement, and area. Intraclass correlation coefficients (ICC), standard error of measure (SEM), minimal detectable change (MDC) and Bland-Altman plots were calculated to show the reliability of COP measures. ResultsICCs ranged from 0.51 to 0.86 for the four trials indicating moderate-to-good reliability. Just the medio-lateral displacement in double leg open eyes condition showed weak reliability (ICC = 0.29). The highest and lowest ICC values (0.86, 0.29) were obtained for COP medio-lateral displacement in double leg open eyes condition and medio-lateral displacement in double leg close eyes condition measures, respectively. SEM (0.03–5.93) and MDC (0.09–16.45) range scores varied. Bland-Altman plots revealed no significant difference between two trials in both opened and closed eyed conditions, indicating strong agreement between assessments. ConclusionThese findings suggest that the WBB was a reliable tool for assessing static and dynamic balance tests in TKA patients, making it as a suitable tool for standing balance assessment in clinical settings.

Use of an inertial sensor and a force platform to assess static balance in participants affected by multibacillary leprosy.

Leprosy is a chronic, slowly developing infectious disease that affects the peripheral nerves, specifically Schwann cells. Individuals with the multibacillary type exhibit a propensity for developing chronic pain and a decrease in sensitivity in the plantar region, which directly interferes with balance maintenance. The evaluation of static balance in this population is made through the measurement of the center of pressure (COP) oscillations. Therefore, there is a need to investigate the association between postural control and COP oscillations using a force platform and finding accelerations of the center of mass (COM) from inertial sensors for reliable and portable balance assessment in leprosy patients. To validate the application of inertial sensors for patients with leprosy by establishing a correlation with the outcomes obtained from a force platform. This is an observational study with a case-control design, in which 30 participants with leprosy and 30 healthy participants were recruited to evaluate static balance using an inertial sensor and a force platform. Participants underwent balance assessment under two conditions (Eyes Open: OE and Eyes Closed: CE), and data from the platform and sensor were processed using Matlab computational routines. The data were quantified using four parameters: Total Displacement (TD), Area, Antero-Posterior Displacement (APdisp), and Medio-Lateral Displacement (MLdisp). The evaluated parameters showed significantly different values between the groups, where the Leprosy group exhibited significantly higher values compared to the control group, both in the OE and CE conditions for all four parameters. The sensor corroborated the differences demonstrated by the platform and followed the same trend for medio-lateral displacements and accelerations. It can be observed that the evaluated parameters exhibited a varied correlation ranging from moderate to large between the platform and the sensor. Among the four variables, MLdisp had the lowest correlation. The results partially confirmed the first hypothesis of concurrent validation, showing a moderate to large correlation between the force platform and the inertial sensor. The second hypothesis of clinical validation was also partially confirmed, as not all group differences observed in the COP measurements from the force platform were reflected in the COM measurements from the inertial sensor. Specifically, the force platform indicated greater oscillations in participants with multibacillary leprosy compared to controls, a finding statistically confirmed by the sensor for all measures except MLdisp. This research confirmed the concurrent validity of the inertial sensor with the force platform and its clinical validation, demonstrating that this instrument can be applied in clinical settings due to its low cost and ease of use. The findings may contribute to public health by identifying postural control tools for patients with multibacillary leprosy.

Assessing the Adequacy of Orbital Reconstruction With Titanium Mesh Using Clinical and Radiological Measures.

Background Orbital reconstruction aims to restore the original orbit volume and correct diplopia, enophthalmos, and ocular motility of the fractured orbit. This study aimed to assess the adequacy of orbital reconstruction using radiological and clinical factors. Methods In this retrospective study, patients with orbital blowout fractures meeting clinical or radiographic criteria underwent orbital reconstruction with titanium mesh. The orbital volume and anteroposterior displacement were calculated pre- and post-operatively using computed tomography. Diplopia, inferior orbital nerve examination, and ocular movement were also evaluated. Pre- and post-operative orbital volumes of the fractured and contralateral unfractured orbits were compared. Statistical analysis was performed using MS Excel (Redmond, USA) and STATA BE (Texas, US). Results There was a significant reduction in the difference in volumes between fractured and normal orbits postoperatively (p-value <0.001). The mean difference between the reconstructed orbital floor fracture and the contralateral normal orbit was 0.55 cm3, which is within the normal anatomic variation. Enophthalmos was corrected postoperatively in our patients per radiological parameters as a result of a reduction in the mean posterior displacement. Infraorbital nerve hypoesthesia was not resolved postoperatively. Conclusion Our study highlights the restoration of the normal anatomical variation in volume differences between the fractured and contralateral orbits post-surgery using CT-guided analysis, thereby improving clinical outcomes.

Anterior cruciate ligament reconstruction in the elderly: 5-Year follow-up study

BackgroundOlder adults remain active for longer and continue sports and activities that require rotation on one leg later in life. The rate of anterior cruciate ligament (ACL) tears is therefore increasing in those over 40 years old, with an associated increase in the rate of surgical reconstruction (ACLR), but there is limited literature on its effectiveness. Our aim was to compare the outcomes of elderly patients who have undergone ACLR with those of a younger group of patients. Materials and MethodsPatients who underwent ACLR with bone-patella tendon-bone grafting (BPTB) at a level I trauma center between 2015 and 2017 were included in the study with a 5-year follow-up. Patients were divided into 4 groups: below 40 years, 40–49 years, 50–59 years and over 60 years. The graft function was evaluated by the International Knee Documentation Committee (IKDC) Objective Score, the anteroposterior (AP) displacement was measured by arthrometer (KT-1000; MEDMetric) and the Lysholm scale was used for subjective evaluation. Results195 patients were included in the final analysis. The IKDC score showed significantly poorer scores in the 50–59 years and over 60 years group than in the younger groups, however in 83 % and 66 % of cases reached normal or nearly normal grades, respectively. A significant difference was found in the knee AP displacement (measured in mm) between the below 40 years group and 50–59 years as well as over 60 years old groups; however, the number of graft failure (laxity >5 mm) and elongation (>3 mm) did not increased in these senior groups. The patient-reported Lysholm scores in the 40–49 years, 50–59 years and 60 years groups was lower than in the below 40 years group, but the average score was “good”. ConclusionsThe long-term results of ACL reconstruction in older athletes are comparable to those of younger patients, both in terms of knee function and patient satisfaction. Furthermore, there is no difference in outcomes for older patients over the age of 40 compared to those in their 50 s or even 60 s. There is still insufficient published evidence to define an upper age limit for ACL reconstruction in older athletes.

The effect of cervical traction on stabilometric parameters in cervical radiculopathy patients: A randomized crossover study.

Cervical traction is effective on pain and function in patients with cervical radiculopathy but its effectiveness on balance disorders has not yet been studied. To evaluate the effect of mechanical intermittent cervical traction (MICT) on stabilometric parameters in patients with cervical radiculopathy. This randomized crossover study assigned 20patients with cervical radiculopathy to one of the two groups: Group effective traction (ET)/sham traction (ST) (n= 10) treated firstly with ET (traction force of 12Kg) then with ST (traction force of 2Kg) with one-week interval and group ST/ET (n= 10) treated invertedly with a ST then ET. Each traction procedure was maintained for 10minutes twice separated by 5minutes of rest. Patients were assessed before and immediately after MICT procedure. Main outcome measures were stabilometric parameters: center of pressure, sway area and lateral and anteroposterior displacements using a force platform. Secondary outcome measures were pain intensity, grip strength and dizziness. ET has provided a significantly greater improvement in both groups and in the total population in terms of stabilometric parameters (p< 0.01), pain intensity, and grip strength (p< 0.05), compared to ST. MICT seems to have an immediate beneficial effect on stabilometric parameters, pain and grip strength in patients with cervical radiculopathy.

Investigating the Influence of Varying Surface Conditions on Human Postural Control and Sensory Integration Strategies.

This study investigated the effects of different surface conditions on postural stability in response to unexpected perturbations. Thirty healthy adults underwent balance assessments on flat, incline ramp, balance pad, and balance pad on incline ramp surfaces. The center of pressure (COP) displacement in the mediolateral (ML) and anteroposterior (AP) directions, the velocity, and the area were measured. We found that the flat and ramp conditions resulted in significantly lower COP ML (F(3, 87) = 38.272, p < 0.001, ηp2 = 0.569) and AP displacements (F(3, 87) = 89.177, p < 0.001, ηp2 = 0.755), velocity (F(3, 87) = 89.177, p < 0.001, ηp2 = 0.755), and area (F(3, 87) = 52.659, p < 0.001, ηp2 = 0.645) compared to the balance pad and balance pad on ramp conditions (p < 0.05). The use of a balance pad, particularly on a ramp, significantly increased all the COP measurements, suggesting greater challenges to postural control. Through these findings, we demonstrate the adaptability and limitations of the human postural control system in response to varying surface conditions and perturbations.

Relationship among the COM Motion, the Lower Extremity and the Trunk during the Squat.

Squatting is a common motion in activities of daily living and is frequently used in training programs. Squatting requires a shift of the body in both vertical and anterior-posterior directions. Postural control during squatting is considered a mixed strategy; however, details and roles of the trunk and lower limb joints are unclear. The purpose of this study was to investigate the relationship among the kinematics of the lower limb, the trunk and the center of mass (COM) descent during squatting. Twenty-six healthy young adults performed repeated parallel squats. Lower limb joint and trunk angles and the COM were analyzed using a 3D motion analysis system. We evaluated the relationship between the kinematics and the squat depth by performing correlation analysis and multiple linear regression analysis. The ankle was the first to reach its maximum angle, and the remaining joints reached their maximum angles at the maximum squat depth. The knee joint motion and the squat depth were significantly correlated and there was a correlation between the hip and the ankle joint motion and the anteroposterior displacement of the COM during squatting. Multivariate linear regression analysis indicated that squat depth was predicted by both the knee and ankle motion and that anteroposterior displacement of the COM was predicted by the hip, ankle, and knee joint motion. The knees contributed to the vertical COM motion during squatting, while the hips contributed to the COM motion in the anteroposterior direction. On the other hand, the ankles contributed to COM motions in both the vertical and anteroposterior directions during squatting.

Effects of Combining Transcranial Direct Current Stimulation With Balance Training on Anticipatory Postural Adjustments in Persons With Chronic Ankle Instability.

The combination of transcranial direct current stimulation (tDCS) with balance training could integrate central and peripheral neural mechanisms. This study aimed to investigate the effects of concurrent balance training and tDCS over the supplementary motor area (SMA) on anticipatory postural adjustments during gait initiation (GI) in persons with chronic ankle instability (CAI). Balance training will increase the center of pressure (COP) velocity and displacement during GI phases in all participants, and those receiving real tDCS will show greater increases. Randomized controlled trial. Level 2. A total of 32 subjects were allocated to 2 groups: (1) intervention (balance training plus real tDCS) and (2) control (balance training plus sham tDCS). Outcome measures were COP-related parameters (displacement and velocity) during phases of GI (anticipatory, weight transition, and locomotor). The results showed that, in the anticipatory phase, the anteroposterior displacement of the COP was increased significantly at posttest relative to pretest across both groups, F(1,30) = 5.733, P = 0.02. In addition, both groups revealed an increase in the mediolateral COP velocity at posttest, F(1,30) = 10.523, P < 0.01. In the weight transition phase, both groups had higher mediolateral COP velocity at posttest, F(1,30) = 30.636, P < 0.01. In the locomotor phase, in both groups, the anteroposterior COP velocity was increased significantly at posttest compared with pretest, F(1,30) = 5.883, P = 0.02. Both groups demonstrated improvements in the anticipatory and execution phases of GI. Since no between-group difference was found, it can be interpreted that the anodal tDCS applied over the SMA has no added value over sham stimulation. Balance training is beneficial for persons with CAI and can improve the anticipation and execution phases of GI without the aid of brain stimulation.

A Controlled Variable Study of the Biomechanical Properties of the Proximal Femur before and after Cancellous Bone Removal.

The biomechanical characteristics of proximal femoral trabeculae are closely related to the occurrence and treatment of proximal femoral fractures. Therefore, it is of great significance to study its biomechanical effects of cancellous bone in the proximal femur. This study examines the biomechanical effects of the cancellous bone in the proximal femur using a controlled variable method, which provide a foundation for further research into the mechanical properties of the proximal femur. Seventeen proximal femoral specimens were selected to scan by quantitative computed tomography (QCT), and the gray values of nine regions were measure to evaluated bone mineral density (BMD) using Mimics software. Then, an intact femur was fixed simulating unilateral standing position. Vertical compression experiments were then performed again after removing cancellous bone in the femoral head, femoral neck, and intertrochanteric region, and data were recorded. According to the controlled variable method, the femoral head, femoral neck, and intertrochanteric trabeculae were sequentially removed based on the axial loading of the intact femur, and the displacement and strain changes of the femur samples under axial loading were recorded. Gom software was used to measure and record displacement and strain maps of the femoral surface. There was a statistically significant difference in anteroposterior displacement of cancellous bone destruction in the proximal femur (p < 0.001). Proximal femoral bone mass explained 77.5% of the strength variation, in addition proximal femoral strength was mainly affected by bone mass at the level of the upper outer, lower inner, lower greater trochanter, and lesser trochanter of the femoral head. The normal stress conduction of the proximal femur was destroyed after removing cancellous bone, the stress was concentrated in the femoral head and lateral femoral neck, and the femoral head showed a tendency to subside after destroying cancellous bone. The trabecular removal significantly altered the strain distribution and biomechanical strength of the proximal femur, demonstrating an important role in supporting and transforming bending moment under the vertical load. In addition, the strength of the proximal femur mainly depends on the bone density of the femoral head and intertrochanteric region.

Evaluation of mandibular motion in adolescents with skeletal class II division 1 malocclusion during mandibular advancement using clear functional aligners: a prospective study

BackgroundThis study aimed to evaluate the characteristics of mandibular protrusive condylar trajectory in adolescents with skeletal Class II Division 1 malocclusion and the changes of condylar trajectory during mandibular advancement (MA) treatment using clear functional aligners.MethodsThis prospective study consisted of a cross-sectional study and a longitudinal study. In cross-sectional study, sixty-one adolescents were divided into two groups: Class I (n = 30) and Class II Division 1 (n = 31). The condylar trajectory was measured and compared using the Mann–Whitney U test. The longitudinal study was the MA treatment group using clear functional aligner and consisted of 16 participants from Class II Division 1group. The condylar trajectory was collected at three-time points: pre-treatment (T1), during MA treatment at approximately 3 months (T2, 105.6 days average), and at the end of MA treatment (T3, 237.6 days average). The changes at T1, T2, and T3, as well as the symmetry between the left and right condyles across all groups, were examined using the Wilcoxon paired test.ResultsA greater increase in the anteroposterior displacement and space displacement during protrusive movements was observed in the Class II Division 1 group compared with that in the Class I group, with a large difference being observed in the left and right condylar movements. The condylar anteroposterior displacement and space displacement decreased significantly at T2 and increased significantly at T3; however, no significant difference was observed between T1 and T3. A significant difference was observed between the condylar movement on the left and right sides at T1; however, no significant difference was observed at T2 and T3.ConclusionsAdolescents with Class II Division 1 malocclusion had higher protrusive capacity than those with Class I. Moreover, their left and right condylar motion was more asymmetric. The range of condyle motion decreased first and then increased during MA therapy, and the left and right condyle movement became more symmetrical, which may be the adaptive response of neuromuscular function to the changes in jaw position.

Criteria of ultrasound-guided closed reduction with percutaneous pinning in unstable humeral lateral condylar fractures: a three-center retrospective cohort study.

Interventions using ultrasound-guided closed reduction and percutaneous pinning (UG-CRPP) of humeral lateral condylar fractures (HLCFs) have been increasingly applied; however, their effectiveness for unstable HLCFs and the criteria for ultrasound outcomes remain unclear. This study assessed the outcomes of UG-CRPP for HLCFs and evaluated the success criteria in children. Data were retrospectively collected from 106 patients with unstable HLCFs admitted to three hospitals between January 2021 and August 2022. Fifty-five cases were left-sided and 51 cases were right-sided: 74 male patients and 32 female patients were included. Perioperative data, elbow function, complications, and criteria for UG-CRPP were analyzed. The mean rate of UG-CRPP was 88%. The mean surgical time was 54.56 ± 21.07 min, and the mean fluoroscopy frequency was 9.25 ± 2.93 times. At the last follow-up, there were significant differences in elbow flexion between the affected side (135.82° ± 6.92°) and the unaffected side (140.58° ± 5.85°) (p = 0.01). The Mayo score of the affected side was 90.28° ± 4.97°, the Baumann angle was 71.4° ± 5.4°, condylar shaft angle was 39.9° ± 6.4°, and the carrying angle was 8.4° ± 3.6°. Seventy patients presented mild lateral spurs and 16 patients exhibited moderate spurs. Fourteen patients presented with pin infection, and one patient exhibited postoperative re-displacement. There was no premature physeal closure, varus, or valgus elbow deformity, delayed union, or non-union. Successful ultrasound-based outcome criteria for UG-CRPP were defined as follows: (i) absent or less than a cartilage thickness step on the cartilage hinge on coronal plane parallel articular surface scanning, (ii) no lateral displacement and intact distal end of the condylar and capitellum on coronal plane vertical articular surface scanning, (iii) no anteroposterior displacement and absent or less than a cartilage thickness step on sagittal plane vertical articular surface scanning, and (iv) intact posterior fracture line or less than a cortex step on posterolateral sagittal plane vertical articular surface scanning. UG-CRPP is a procedure with minimal blood loss, less invasive, cosmetic, and no radiation exposure. It yielded good outcomes in unstable HLCFs. The successful criteria make it suitable for clinical application.

Postural balance in COPD with obstructive sleep apnoea: a cross-sectional study.

The aim of this study was to assess the postural balance in COPD patients with obstructive sleep apnoea (OSA). Physical activity, anxiety and depression symptoms, mood, and falls were also assessed in this population. Moderate to severe COPD patients were assessed for laboratory and clinical postural balance (force platform and mini-balance evaluation systems test (Mini-BESTest)), physical activity (accelerometry), OSA (polysomnography), sleep quality (Pittsburgh Sleep Quality Index), sleepiness (Epworth Sleepiness Scale), anxiety and depression symptoms (Hospital Anxiety and Depression Scale), dyspnoea (modified Medical Research Council), clinical status (COPD Assessment Test) and mood (Brunel Mood Scale). Self-reported falls were recorded for 6 months via phone calls. COPD patients (n=70) were divided according to the polysomnography findings into the no OSA (n=30), mild OSA (n=25), and moderate to severe OSA (n=15) groups. Compared to patients with no OSA, those with moderate to severe OSA (msOSA group) presented median (interquartile range) increased path length (30.5 (23.9-34.5) cm versus 39.0 (30.6-52.6) cm, anteroposterior displacement (1.89 (1.39-2.31) cm versus 2.54 (2.06-2.83) cm and postural adjustment velocity (1.02 (0.80-1.15) cm·s-1 versus 1.30 (1.02-1.76) cm·s-1) (p<0.05). No differences were observed in the Mini-BESTest scores among the groups. The msOSA group presented a greater number of recurrent fallers in the first follow-up trimester. No association was observed between postural balance and age and pulmonary function. Individuals with COPD and moderate to severe OSA present changes in postural balance, including broader oscillation, faster postural adjustments and a greater risk of falls than those with no OSA. Physical activity, anxiety and depression symptoms, and mood are similar between COPD patients with and without OSA.

Effect of clear aligner type on maxillary full-arch intrusion: 3D analysis using finite element method

BackgroundVertical maxillary excess (VME) is one of the most common reasons for seeking orthodontic treatment. Total intrusion with aligners is a promising alternative to surgery in some cases. Considering the elastic deformation of aligners, this study aimed to evaluate the possible desirable and undesirable teeth displacements during full maxillary arch intrusion using clear aligners and temporary anchorage devices (TADs).MethodsThe maxillary arch and clear aligners were modeled in SolidWorks. Four aligner brands including Leon, Duran, Duran Plus, and Essix Plus were selected based on their material properties. Anterior and posterior intrusion forces of 80 and 300 g were applied from attachments between the canines and first premolars and between the first and second molars, respectively. Vertical and anteroposterior tooth displacements were determined.ResultsThe greatest intrusion was recorded at the buccal of the second molar, followed by the first molar. The lowest value was measured at the palatal of the molars with all aligners except Duran, which indicated minimal intrusion in the central incisor. All teeth were mesially displaced at the incisal/occlusal except incisors that moved distally. All apices showed distal movement.ConclusionsTotal intrusion using clear aligners may be accompanied by other tooth movements, including buccal tipping and mesial-in rotation of the molars, retrusion of incisors, and mesial movement of other teeth.

Relationship between Car-Sickness Susceptibility and Postural Activity: Could the Re-Weighting Strategy between Signals from Different Body Sensors Be an Underlying Factor?

Postural control characteristics have been proposed as a predictor of Motion Sickness (MS). However, postural adaptation to sensory environment changes may also be critical for MS susceptibility. In order to address this issue, a postural paradigm was used where accurate orientation information from body sensors could be lost and restored, allowing us to infer sensory re-weighting dynamics from postural oscillation spectra in relation to car-sickness susceptibility. Seventy-one participants were standing on a platform (eyes closed) alternating from static phases (proprioceptive and vestibular sensors providing reliable orientation cues) to sway referenced to the ankle-angle phases (proprioceptive sensors providing unreliable orientation cues). The power spectrum density (PSD) on a 10 s sliding window was computed from the antero-posterior displacement of the center of pressure. Energy ratios (ERs) between the high (0.7-1.3 Hz) and low (0.1-0.7 Hz) frequency bands of these PSDs were computed on key time windows. Results showed no difference between MS and non-MS participants following loss of relevant ankle proprioception. However, the reintroduction of reliable ankle signals led, for the non-MS participants, to an increase of the ER originating from a previously up-weighted vestibular information during the sway-referenced situation. This suggests inter-individual differences in re-weighting dynamics in relation to car-sickness susceptibility.