Anteroposterior Position Research Articles

Condylar Changes in Adult Patients with Unilateral Posterior Crossbite Following Microimplant-Assisted Rapid Palatal Expansion: A Retrospective CBCT Study.

This study aims to assess the alterations in condylar positioning in adult skeletal Class I patients with unilateral posterior crossbite after microimplant-assisted rapid palatal expansion (MARPE) treatment. This retrospective study involving 30 participants (10 males, 20 females) average age 22.9 ± 4.2 years and they ranged in age from (18.1 to 30.9 years) who treated with a customized microimplant-supported rapid palatal expander. Pre-expansion and post comprehensive orthodontic treatment CBCT images (20-26 ±2.1months) were analyzed to assessed the condylar changes before and after treatment. We measured the temporomandibular joint (TMJ) in 3D in terms of: (1) the position, angle and tilt of the mandibular condyles; (2) how centralized the condyles were in their particular mandibular fossae; and (3) the volume of the TMJ and TMJ spaces. To evaluate the differences between the T1 and T2 samples, we used the paired t-test and the Wilcoxon signed rank test. Before treatment, minor differences were noted in the anterior joint space (AJS), superior joint space (SJS), and anteroposterior condylar joint position (APCJP) between the crossbite and non-crossbite sides, though these differences were not statistically significant. Post-treatment, the condyles on both sides assumed a more posterior position, yet significant asymmetry in the AJS persisted (P < .05). The crossbite-side condyle also showed a tendency to rotate toward the non-crossbite side in the anteroposterior direction. While MARPE affected specific aspects of condylar positioning, achieving complete alignment remained challenging. This study provides insightful observations on the enduring impacts of MARPE on TMJ spaces and position in adult patients suffering from a unilateral posterior crossbite.

The effects of cage on endplate collapse after stand-alone OLIF: based on finite element analysis and in vitro mechanics experiments.

Lumbar degenerative diseases are an important factor in disability worldwide, and they are also common among the elderly population. Stand-Alone Oblique Lumbar Interbody Fusion (Stand-Alone OLIF) is a novel surgical approach for treating lumbar degenerative diseases. However, long-term follow-up after surgery has revealed the risk of endplate collapse associated with Stand-Alone OLIF procedures. This study aimed to investigate the effect of the cage factor on endplate collapse after Stand-Alone OLIF. Finite element (FE) models and calf lumbar functional units were established separately and used to simulate Stand-Alone OLIF surgery. On the L5 endplate of the FE model and the calf lumbar functional unit, 12 cage positions from anterior to posterior, 16 cage inclination angles from 0° to 15°, and 4 cage heights were selected to simulate surgical models with different cage positions. Compression loads of 400N were applied to the upper surface of the superior vertebral body of the cage, and 10Nm torques in four directions were used to simulate four different physiological movements of the lumbar spine: flexion, extension, lateral curvature and torsion, in order to compare the range of motion of the surgical segment and the endplate stress. When the cage is placed closer to the anterior and posterior edges of the endplate and when the height of the cage exceeds 12mm, the intervertebral range of motion at the surgical segment is greater and the stress on the endplate is higher during various lumbar spine activities. When the cage is inclined at an angle within 15°, there are no significant differences in the corresponding endplate stress and the range of motion. For Stand-Alone OLIF surgery, inserting the cage in the central anterior-posterior position of the intervertebral space and selecting a cage with a height not exceeding 12mm can reduce the stress on the endplate after surgery, which is more conducive to the stability of the lumbar spine postoperatively and reduces the risk of postoperative endplate collapse. The inclination angle of the cage placement does not significantly affect postoperative endplate stress or lumbar stability.

The presence of a Segond fracture in ACL-injured patients is associated with increased internal tibial rotation on preoperative MRIs

BackgroundSegond fracture is considered a component of the anterolateral complex (ALC) injury, yet the underlying cause and clinical outcomes of this bony avulsion remain subjects of debate. Additionally, MRI measurements of altered tibiofemoral position in anterior cruciate ligament (ACL)-injured patients with a Segond fracture have not been reported. The purpose of this study is to measure the rotational tibiofemoral position on MRI in ACL-injured patients with a Segond fracture.MethodsA total of 44 patients with a primary ACL injury and a concomitant Segond fracture were included in the Segond fracture group, with the time from injury to MRI within 3 months. Avulsion was confirmed via preoperative computed tomography (CT) scans. The control group comprised 44 matched patients with primary ACL injury and an MRI-determined ALC injury but without a Segond fracture, also with the time from injury to MRI within 3 months. The MRI-determined ALC injury included injuries to the anterolateral ligament, Kaplan fibers, and anterolateral joint capsule, as identified based on previous studies. Sex, age, and BMI were matched between the two groups using propensity score matching (PSM). Arthroscopic findings, concomitant collateral ligament injuries, and preoperative MRI measurements were compared between the two groups.ResultsThe Segond fracture group demonstrated a higher frequency of concomitant patellar and femoral trochlear injuries (p = 0.0110) and lateral collateral ligament injuries (p = 0.0121) compared to the control group. Additionally, significantly increased internal rotational tibial subluxation (IRTS) (p = 0.0095) and axial internal tibial rotation (ITRa) (p = 0.0306) were observed in the Segond fracture group. A strong positive correlation was found between IRTS and ITRa (rp = 0.8201), indicating that these two tibial rotation measurement methods were correlated. No significant differences were observed in the measurements of anteroposterior tibiofemoral position and posterior tibial slope (PTS) between the two groups.ConclusionThe presence of a Segond fracture was associated with significantly increased internal tibial rotation measured on MRIs, suggesting that this bony avulsion may represent a more severe form of ALC injury in ACL-injured patients and should be managed with caution.

Reverse Shoulder Arthroplasty Implant Design and Configuration has a Significant Effect on Conjoint Tendon Impingement

BackgroundAnterior shoulder pain after reverse shoulder arthroplasty (RSA) is not uncommon and may be due to humeral impingement against the conjoint tendon during internal rotation (IR). It is unknown what effect different implant designs and configurations have on conjoint tendon impingement. The purpose of this study was to investigate the influence of several RSA implant design parameters on conjoint tendon impingement during IR. MethodsTwelve upper extremity cadavers were dissected to visualize and digitize the path of the coracobrachialis using a tracking system. This data was transformed onto the corresponding computer tomography derived bone models, while previous literature was used to approximate the muscle attachment locations for the conjoint tendon origin and short head of the biceps insertion. Each model then underwent three-dimensional virtual RSA implantation using a generic implant design. A baseline configuration was first implanted which utilized a 25mm glenoid baseplate placed in 0° inclination and version and positioned flush to the inferior glenoid rim with a 36mm glenosphere. The humeral baseline configuration consisted of an implant placed in 20° retroversion at a neck-shaft-angle (NSA) of 135°, centered on the humeral cut plane with a zero-thickness polyethylene cup. Additional implant designs were then configured by independently changing various design parameters including glenoid lateralization, glenosphere diameter, glenoid baseplate position, humeral polyethylene thickness, humeral component position, humeral NSA, and humeral version. Each implant configuration was then examined using a custom motion software which modeled the muscle path of both the coracobrachialis and short head of the biceps. IR was performed until conjoint tendon impingement was detected. All implant configurations were compared using a repeated measures analysis of variance (P<0.05). ResultsGlenosphere size, glenoid baseplate anterior-posterior and superior-inferior position, humeral polyethylene insert thickness, humeral anterior-posterior and medial-lateral position, and humeral version significantly influenced conjoint tendon impingement (P<0.001). Glenoid lateralization and humeral NSA did not have a significant effect on conjoint tendon impingement (P>0.293). Overall, earlier conjoint tendon impingement occurred with larger glenosphere sizes, anteriorly and superiorly positioned glenoid baseplates, greater polyethylene thickness, medially and posteriorly positioned humeral implants, and greater humeral retroversion. ConclusionRSA implant parameters and positions have been identified that can significantly increase the risk of conjoint tendon impingement, such as larger glenospheres, anterosuperior baseplate & glenosphere positioning, humeral implants or trays positioned medial and posterior, and increased humeral component retroversion. These results may be considered by surgeons preoperatively to limit conjoint tendon impingement, or intra-operatively when conjoint tendon impingement is identified.

Perception of facial esthetics and cephalometric correlations in Class II patients: a comparison between two-phase and one-phase treatments

An effective orthodontic treatment should not only aim for satisfactory occlusal outcomes but also consider its impact on facial esthetics. The study aims to evaluate and compare the perception of profile esthetics of skeletal Class II patients treated with two orthodontic modalities: (1) Two-phase approach involving functional appliances followed by fixed appliances with premolar extractions, or (2) One-phase approach using fixed appliances with premolar extractions. Additionally, the study aims to evaluate the correlation between the perceived esthetics and the corresponding cephalometric measurements. The study included 40 skeletal Class II adolescents who underwent either two-phase (n = 20, mean age = 12.38 ± 1.18) or one-phase (n = 20, mean age = 12.53 ± 0.79) orthodontic treatments. Eighty profile silhouettes (pre- and post-treatment) were assessed by 64 raters, including 23 orthodontists, 21 general dental practitioners, and 20 laypersons. The raters used a visual analog scale (VAS) to access profiles, upper and lower lips, and chin esthetics. At pre-treatment, all three groups of raters gave significantly lower scores to the profile silhouettes of the two-phase group compared to the one-phase group (P < 0.01); however, after treatment, they rated the two-phase group significantly higher (P ≤ 0.001). The two-phase group exhibited greater improvements in profile and upper and lower lip esthetics as perceived by all raters (P ≤ 0.001). Furthermore, cephalometric results revealed greater reductions in SNA, ANB, Wits appraisal, and G’-Sn-Pog’ in the two-phase group compared to the one-phase group (P < 0.05). Five cephalometric parameters (SNB, SNPog, overjet, overbite, and UL-SnPog’) demonstrated significant correlations with VAS scores given by orthodontists (P < 0.05). In conclusion, the two-phase group showed greater subjective and objective improvements in facial esthetics than the one-phase group. Additionally, the anteroposterior mandibular position and upper lip protrusion may be the primary cephalometric parameters correlated with subjective facial profile perceptions.

The Tibial Tunnel Size Relative to the Proximal Tibia Affects the Tibial Tunnel Widening in Anatomical Anterior Cruciate Ligament Reconstruction.

The impact of the bone tunnel size relative to body size on clinical results in anterior cruciate ligament (ACL) reconstruction remains unclear. This study aimed to assess the morphological alteration of the tibial tunnel aperture and relationship between the tibial tunnel size relative to the proximal tibia among the tibial tunnel widening (TW) and clinical results following ACL reconstruction. This study comprised 131 patients who had undergone anatomical ACL reconstruction utilizing bone-patellar tendon-bone autografts. The morphology and enlargement of the tibial tunnel were examined via three-dimensional computed tomography 1 week and 1 year postoperatively. The anteroposterior (AP) and mediolateral (ML) positions were determined as a percentage relative to the proximal AP and ML tibial dimensions, respectively. Clinical assessment was conducted 2 years postoperatively. The association between the primary tibial tunnel size among TW and clinical outcomes was examined. The tibial tunnel significantly migrated posterolaterally. The ML diameter significantly widened; however, the AP diameter did not exhibit widening. AP widening was associated with the AP diameter of the primary tibial tunnel (r = -0.482, p < 0.01), and ML widening correlated with the ML diameter of that tunnel (r = -0.478, p < 0.01). However, there was no significant correlation observed between the primary tibial tunnel size and clinical outcomes. The tibial tunnel migrated and enlarged laterally in the ML plane, but did not enlarge in the AP plane. The primary tibial tunnel diameter relative to the proximal tibia negatively correlated with the tibial TW in the AP and ML planes. Level of evidence: level IV.

Evaluation of a novel robotic testing method for stability and kinematics of total knee arthroplasty.

This work developed a novel preclinical test of total knee replacements (TKRs) in order to explain TKR instability linked to patient dissatisfaction. It was hypothesized that stability tests on the isolated moving prostheses would provide novel comparative data on the stability and kinematics among TKR designs. Three TKR designs, DePuy Synthes Attune MS, Stryker Triathlon and Zimmer Biomet Persona MC, were assessed using a robotic arm while flexing-extending 0-140°. Tests imposed 710 N body weight combined with three tibial loads: no anterior-posterior (AP) force, 90 N anterior or 90 N posterior force. Other load effects were minimized and the kinematics was recorded. Each implant was tested six times to investigate the repeatability of the method. Data were analysed using statistical parametric mapping with one-way analysis of variance (ANOVA). If significance was found (p < 0.05), post hoc t tests with Bonferroni correction were used to contrast groups. Significant differences were found throughout flexion-extension. Femoral rollback, AP stability, coupled internal-external rotation and AP position (roll-back) were all influenced by implant design. AP stability of the TKRs reduced with flexion reaching Attune 15 mm, Persona 13 mm and Triathlon 21 mm at 140° flexion. Tractive rolling significantly affected kinematics in the less congruent Triathlon design, with 6 mm different paths between flexion and extension motion (p < 0.05 across 5-100°). Paradoxical anterior femoral sliding in early flexion (0-40°) occurred in Persona and Triathlon designs. The novel testing technique provides, for the first time, comparative data on the inherent stability and kinematics of the TKR implants themselves across the arc of flexion-extension, independent of variables including soft tissue behaviour and surgical technique. The data show how much each prosthesis can contribute to the stability and motion of the implanted knee. Similar data from a wider range of designs will enable more informed decisions regarding implant design choice, aiming to reduce the prevalence of TKR instability in patients. Controlled laboratory study.

Preoperative tibiofemoral contact point on standing lateral radiograph predicts anteroposterior knee kinematics in total knee arthroplasty.

This study investigated the tibiofemoral contact point (CP) on standing lateral radiographs in knee osteoarthritis and assessed the relationship between CP and pre- and postoperative knee kinematics in total knee arthroplasty (TKA). The intraoperative knee status of 46 knees with varus deformity that underwent bicruciate stabilized TKA using a navigation system was investigated. The intraoperative anteroposterior (AP) position of the femur relative to the tibia at maximum extension, 15°, 30°, 45°, 60° and 90° was evaluated by the navigation system before and after TKA. The CP, defined as the CP between the femur and tibia, was assessed on standing lateral radiographs at the maximum extension of the knee before and 1 year after TKA. CP was expressed as the ratio of tibial plateau distance on a scale of 0-1, with 0 indicating the most anterior position of the femur relative to the tibia. The mean CP on standing lateral radiographs was 0.54 ± 0.12 and 0.46 ± 0.08 before and after TKA, respectively. The postoperative CP was significantly more anterior than the preoperative CP (p = 0.0002). The mean AP position of the femur relative to the tibia moved anteriorly during early knee flexion both before and after TKA, representing nonanatomical AP movement. The preoperative posterior CP group (CP > 0.54) showed more nonanatomical AP movement from 15° to 60° before and after TKA compared with the preoperative anterior CP group (CP < 0.54). Preoperative posterior deviation of the femur relative to the tibia in the standing position was a predictive factor for nonanatomical AP knee kinematics. Biomechanical analysis of postoperative knees will be necessary; however, surgeons should focus on preoperative tibiofemoral CP on standing lateral radiographs to predict knee kinematics. Level Ⅲ.

Harmonizing soft tissue subnasale and chin position in a forehead-based framework: interracial commonalities and differences between Asian and Caucasian females.

To establish a reference system for assessing the anteroposterior (A-P) position of the subnasal and lower-facial soft tissues for whole facial harmony. Forty Asian and 40 Caucasian females with attractive profiles were selected as the "attractive" samples, with "ordinary" samples for comparison. Each profile was analyzed, and comparisons were made to reveal the interracial commonalities and differences. Esthetically essential parameters were established. An averaged attractive profile for each race was created by digital morphing and then modified into 30 variations based on combined variations of the esthetically essential parameters. Assessments were performed to investigate the esthetic ranges. A-P position of the subnasal and lower-facial landmarks harmonized with the forehead for female profile esthetics. In addition to balanced soft tissue subnasale (sSn)- and soft titssue pogonion (Pos)-to-forehead A-P relations, harmonizing lower-facial soft tissues to sSn was indispensable for profile attractiveness. sSn-to-glabella, Pos-to-glabella, and Pos-to-sSn A-P relations were esthetically essential. Perceived by orthodontists, the attractive Asian female profiles had sSn-to-glabella A-P relations ranging from 0.5 mm to 4.5 mm, Pos-to-sSn from -9.0 mm to -5.5 mm, and Pos-to-glabella from -8.5 mm to -1.0 mm. Compared with Asians, the attractive Caucasian female profiles had more anteriorly and widely distributed sSn relative to the forehead, wider ranges of Pos-to-sSn A-P relations, and more prominent chins. A reference system comprising sSn-glabella, Pos-sSn, and Pos-glabella horizontal distances was constructed for facial profile analysis. This system could aid treatment planning for surgical or orthopedic repositioning of the maxilla and chin.

A Novel Shielding Device for Cardiac Cath Labs.

This research evaluates the effectiveness of a large specialized cardiac catheterization laboratory shielding device (SCCLSD) placed perpendicular to the patient compared to traditional shielding methods in reducing occupational exposure to scattered x rays, contributing to the ongoing enhancement of radiation safety in the cardiac catheterization laboratory (CCL) setting. An experimental setup involving an anthropomorphic phantom on the catheterization table simulated radiation scatter from a patient. Measurements were taken systematically at various grid points and heights in the CCL using a Fluke 451P ion chamber while mimicking a real interventional scenario. In-air peak exposure rates were analyzed at head, chest, and waist heights in the anteroposterior (AP) position. Results demonstrated that the SCCLSD provided a superior radiation shadow and effective whole-body radiation exposure reduction compared to conventional shielding devices. Considering that conventional shielding requires staff to wear lead aprons, an effective dose equivalent correction factor was applied for exposure measurements without the SCCLSD. Even after the correction factor, the SCCLSD continued outperforming lead aprons and offered whole-body protection, including the head and arms, which is typically neglected with conventional shielding. The SCCLSD also reduces exposure to the eyes, aligning with lower occupational exposure recommendations from ICRP and NCRP. However, proper CCL staff positioning is important in maximizing the effectiveness of the SCCLSD. Future research avenues may explore exposure rates at different C-arm angles to more completely assess the SCCLSD's impact on occupational exposure.

Tibial contact points cannot be used to determine internal-external axial rotation of the native tibiofemoral joint

BackgroundIn the study of tibiofemoral kinematics of the native knee, internal-external (IE) axial rotation is a motion of interest. Locations of contact by the femur on the tibia (termed tibial contact points) have been used to determine IE rotations but such rotations might not be useful due to large error. Hence, our objective was to determine whether tibial contact points are useful in quantifying IE rotations of the native knee. MethodFluoroscopic images of the native knee were analyzed from 25 subjects who performed a weight-bearing deep knee bend. For each subject, 3D bone + cartilage models were created. Following 3D model-to-2D image registration, anterior-posterior (AP) positions of the lowest points and the tibial contact points were computed for each femoral condyle at 0°, 30°, 60°, and 90° of flexion. IE rotations were the angles between lines connecting points in the medial and lateral tibial compartments at different flexion angles. ResultsBased on the lowest points, the tibia rotated internally on the femur primarily during the first 30° of flexion. In this range, mean internal tibial rotation based on tibial contact points was negligible but internal tibial rotation was significantly greater based on lowest points (0° vs 7°, p = 0.0002). At 90° of flexion, the difference was maintained (1.8° vs 8.3°, p = 0.0007). ConclusionWhile tibial contact points are useful in the study of wear of tibial inserts in total knee arthroplasty (TKA), tibial contact points considerably underestimate internal tibial rotation during flexion in the native knee and should not be used to quantify tibiofemoral kinematics.

Manual Chest PRESSURE During Direct Current Cardioversion for Atrial Fibrillation: A Randomized Control Trial (PRESSURE-AF)

BackgroundDirect current cardioversion is frequently used to return patients with atrial fibrillation (AF) to sinus rhythm. Chest pressure during cardioversion may improve the efficacy of cardioversion through decreasing transthoracic impedance and increasing cardiac energy delivery. ObjectivesThis study aimed to assess the efficacy and safety of upfront chest pressure during direct current cardioversion for AF with anterior-posterior pad positioning. MethodsThis was a multicenter, investigator-initiated, double-blinded, randomized clinical trial. Recruitment occurred from 2021 to 2023. Follow-up was until hospital discharge. Recruitment occurred across 3 centers in New South Wales, Australia. Inclusion criteria were age ≥18 years, referred for cardioversion for AF, and anticoagulation for 3 weeks or transesophageal echocardiography excluding left atrial appendage thrombus. Exclusion criteria were other arrhythmias requiring cardioversion, such as atrial flutter and atrial tachycardia. The intervention arm received chest pressure during cardioversion from the first shock. The primary efficacy outcome was total joules required per patient encounter. Secondary efficacy outcomes included first shock success, transthoracic impedance, cardioversion success, and sinus rhythm at 30 minutes post cardioversion. ResultsA total of 311 patients were randomized, 153 to control and 158 to intervention. There was no difference in total joules applied per encounter in the control arm vs intervention arm (355.0 ± 301 J vs 413.8 ± 347 J; P = 0.19). There was no difference in first shock success, total shocks provided, average impedance, and cardioversion success. ConclusionsThis study does not support the routine application of chest pressure for direct current cardioversion in atrial fibrillation (PRESSURE-AF [Investigating the Efficacy of Chest Pressure for Direct Current Cardioversion in Atrial Fibrillation: A Randomized Controlled Trial]; ACTRN12620001028998)

A Cross-Sectional Study Examining Andrews' Analysis in Caucasian and African American Subjects

Andrews' analysis is a commonly utilized instrument to aid in esthetic positioning of the anteroposterior position of the maxillomandibular complex; however, there is limited data regarding use in non-Caucasian subjects. The purpose of this study was to document laypersons preferences of anteroposterior position of the maxillomandibular complex in relation to Andrews' lateral profile analysis in African American (AA) and Caucasian subjects. A cross-sectional study was implemented to evaluate the esthetics of AA and Caucasian subjects. Photographs were taken and simulated with anteroposterior maxillomandibular complex positioning in varying relationships to Andrews' goal anterior line limit. A survey was then designed to select the preferred simulation of the facial profile of each subject. The independent variable was the race of the study subjects. The main outcome was the layperson's preferred lateral facial profile for each subject. The covariates included age, race, sex, education level, income, of the laypersons. A proportion test was used to decide which profile was preferred. Logistic regression analyses were conducted to assess the association between the preference and respondent demographics. P<.05 was considered significant. A total of 264 surveys were distributed, and 250 complete surveys were utilized (response rate=95%). Respondents were majority male (51.2%), aged 35-44 (37.2%), college-educated (57.2%), earning between $20,000 and $50,000 annually (44%), and identified as Caucasian (77.2%). For the female subjects, the respondents preferred+4 and+6mm anterior to goal anterior line limit with 54.2% for the Caucasian and 65.9% for the AA subjects (difference=11.7%; 95% CI:2.7 to 20.7%; P=.008). For the males, 47.4% of the respondents chose 0mm and+2mm for the AA subject, while only 24.9% preferred+2mm for the Caucasian male (difference=22.5%; 95% CI: 13.8 to 31.1%; P<.0001). Respondent demographics were not found to influence selection. The preferred facial profile as judged by laypersons differs between Caucasian and AA subjects when defined through Andrews' analysis.

It is challenging to reproduce both anatomical and functional aspects of anterolateral reconstruction: postoperative 3D-CT analysis of the femoral tunnel position

BackgroundThis study aimed to evaluate the femoral tunnel position and fiber length of the anterolateral ligament (ALL) reconstruction compared with the natural anatomy of the ALL. We also evaluated whether the femoral tunnel position would affect residual pivot shift.MethodsThis study was a retrospective review of 55 knees that underwent ALL reconstruction considering the anatomical and functional aspects, during primary anterior cruciate ligament (ACL) reconstruction in the presence of a high-grade pivot shift or revisional ACL reconstruction. We determined the position of the femoral tunnel and the length of graft using a three-dimensional (3D)-computed tomography (CT) model after ALL reconstruction. We also measured graft excursion during surgery and examined pivot shift 2 years after surgery. We conducted a subgroup analysis of femoral tunnel position, fiber length, isometricity, and residual pivot shift depending on whether the tunnel was anterior or posterior to the lateral epicondyle (LE). We also performed a subgroup analysis depending on whether the ACL reconstruction was primary or revisional.ResultsThe mean femoral tunnel position was 2.04 mm posterior and 14.5 mm proximal from the center of the LE. The mean lengths of the anterior and posterior fibers were 66.6 and 63.4 mm, respectively. The femoral tunnel was positioned more proximally than the anatomical position, and both anterior and posterior ALL fibers were longer than the natural anatomy. The anteroposterior femoral tunnel position was significantly correlated with anterior (p = 0.045) and posterior (p = 0.037) fiber excursion. In the subgroup analysis, there was no significant difference in the residual pivot shift between the posterior and anterior tunnel positions. However, there were significant differences for proximal position (p < 0.001) and fiber length (p = 0.006). There was no significant difference between primary and revisional ACL regarding femoral tunnel position and fiber lengths.ConclusionIt is challenging to reproduce both anatomical and functional aspects of ALL reconstruction in both primary and revision ACL reconstruction. Especially for functional reconstruction, the femoral tunnel tended to be positioned more proximally than the anatomical position. However, the femoral tunnel position did not affect functional clinical outcomes at the 2-year follow-up.Level of evidenceLevel IV Case series.

Association of LSMx and LIMd Angles With Cephalometric Dental and Soft Tissue Parameters of Incisor Proclination and Lip Protrusion.

Soft tissue analysis can be used to assess anatomical features but may or may not accurately correlate with underlying hard tissue morphology, leading to an incorrect perception of malocclusion. This study aimed to assess the reliability of different soft tissue reference lines used to evaluate anteroposterior lip position and the position of incisors and malocclusion and compare it with those assessed via hard tissue angles (LSMx and LIMd) and determine if they are true indicators of underlying protrusion of incisors and malocclusion. A total of 120 pre-treatment lateral cephalometric radiographs were selected where patients were 18-30 years old, diagnosed as Skeletal Class I, II (Division 1 and 2), and III malocclusion. The measurements taken were SN to point A angle (SNA), SN to point B angle (SNB), angle between point A and point B (ANB), upper incisor to SN plane angle (UI-SN), upper incisor to palatal plane angle (UI-PP), incisor mandibular plane angle (IMPA), Ricketts' E line, Sushner's S2 line, nasolabial (NL) angle, mentolabial (ML) angle, LSMx angle, and LIMd angle. In the Class I malocclusion group, when the upper lip was assessed, the distribution of UI-SN, UI-PP, E line to UL, S line to UL, NL angle, and LMax was significantly different statistically (p=0.000), though the assessment of lower variables in Class I malocclusion showed the distribution of IMPA, E line to UL, S line to UL, ML angle, and LMand angle has a statistically significant difference (p=0.007). In Class II Division 2 malocclusion, a significant difference was observed for the upper variables (p=0.000), whereas the distribution of lower values was the same across all the variables (p=0.0724). In the sample of Class III malocclusion, a significant correlation was found in the upper variables, while the distribution among lower variables did not show any significant difference (p=0.211). This study indicates that the upper and lower soft tissue correlation with hard tissue variables is reliable for some variables but not throughout for all. Soft tissue analysis (under study) can be used to assess disproportion, but it fails to correlate to the underlying hard tissue morphology and does not explain the correct malocclusion. Further studies based on 3D diagnosis to formulate a close relationship are encouraged that can help assess soft and hard tissue patterns consistent with one another.

Potential anatomical triggers for plan adaptation of cervical cancer external beam radiotherapy.

This study aimed to identify potential anatomical variation triggers using magnetic resonance imaging for plan adaption of cervical cancer patients to ensure dose requirements were met over an external beam radiotherapy course. Magnetic resonance images (MRIs) acquired before and during treatment were rigidly registered to a pre-treatment computerised tomography (CT) image for 11 retrospective cervix cancer datasets. Target volumes (TVs) and organs at risk (OARs) were delineated on both MRIs and propagated onto the CT. Treatment plans were generated based on the pre-treatment contours and applied to the mid-treatment contours. Anatomical and dosimetric changes between each timepoint were assessed. The anatomical changes included the change in centroid position and volume size. Dosimetric changes included the V30Gy and V40Gy for the OARs, and V95%, V100%, D95% and D98% for the TVs. Correlation with dosimetric and anatomical changes were assessed to determine potential replan triggers. Changes in the bowel volume and position in the superior-inferior direction, and the high-risk CTV anterior posterior position were highly correlated with a change in dose to the bowel and target, respectively. Hence changes in bowel and high-risk CTV could be used as a potential replan triggers.

Artificial Intelligence Measurement of Preoperative Radiographs in Adolescent Idiopathic Scoliosis Based on Multiple-View Semantic Segmentation.

Cross-sectional study. Imaging classification of adolescent idiopathic scoliosis (AIS) is directly related to the surgical strategy, but the artificial classification is complex and depends on doctors' experience. This study investigated deep learning-based automated classification methods (DL group) for AIS and validated the consistency of machine classification and manual classification (M group). A total of 506 cases (81 males and 425 females) and 1812 AIS full spine images in the anteroposterior (AP), lateral (LAT), left bending (LB) and right bending (RB) positions were retrospectively used for training. The mean age was 13.6 ± 1.8. The mean maximum Cobb angle was 46.8 ± 12.0. U-Net semantic segmentation neural network technology and deep learning methods were used to automatically segment and establish the alignment relationship between multiple views of the spine, and to extract spinal features such as the Cobb angle. The type of each test case was automatically calculated according to Lenke's rule. An additional 107 cases of adolescent idiopathic scoliosis imaging were prospectively used for testing. The consistency of the DL group and M group was compared. Automatic vertebral body segmentation and recognition, multi-view alignment of the spine and automatic Cobb angle measurement were implemented. Compare to the M group, the consistency of the DL group was significantly higher in 3 aspects: type of lateral convexity (0.989 vs 0.566), lumbar curvature modifier (0.932 vs 0.738), and sagittal plane modifier (0.987 vs 0.522). Deep learning enables automated Cobb angle measurement and automated Lenke classification of idiopathic scoliosis whole spine radiographs with higher consistency than manual measurement classification.

A methodological proof-of-concept of the teeter-totter effect

ABSTRACT The Nike Vaporfly 4% (VP4) shoe is popular due to its unique design and reported performance benefits. However, the underlying mechanisms responsible for the improvements remain unclear. One proposed mechanism is the teeter-totter effect. This study aimed to 1) experimentally test the teeter-totter theory by estimating the teeter-totter moment (MTT) in the VP4 compared to a flat shoe (CONTROL) and 2) quantify the change in the anterior-posterior position of the centre of pressure (Δxa-p) in the VP4 compared to the CONTROL. Plantar pressures and high-speed video were recorded from 15 runners in two shoe conditions. The VP4 generated a larger propulsion moment, MP, ( ∫ M P dt = 90.46 ± 38.87 Nms; p < 0.001, d = 1.95), suggesting the presence of an MTT in the VP4 ( ∫ M TT dt = 57.16 ± 24.35 Nms) when compared to the CONTROL ( ∫ M P dt = 33.30 ± 14.52 Nms). Δxa-p was greater in the VP4 (Δxa-p = 9.48 ± 6.08 mm; p < 0.001, d = 2.07) compared to the CONTROL (Δxa-p = 0.54 ± 0.67 mm). This study provides a methodological proof-of-concept for the teeter-totter theory. The findings highlight the possibility of a teeter-totter effect resulting in greater heel propulsion while running in an AFT shoe construction, assuming a constant muscle moment and pivot point.

Analysis of maxillary teeth and soft tissue profiles among Tibetan and Han Chinese females with facial symmetry for orthodontic treatment planning.

The evaluation of maxillary teeth and soft tissue profiles is a critical component of orthodontic diagnosis and treatment planning. This study aimed to evaluate the correlation between the sagittal position of maxillary anterior teeth and facial profile esthetics among Tibetan and Han Chinese adult females for optimizing orthodontic diagnosis and treatment planning. A total of 100 Tibetan Chinese and 100 Han Chinese adult females with good facial symmetry were recruited. The smiling facial profile images with the maxillary central incisors and forehead in full view were taken based totally on the same standard. The photo measurement and head position were adjusted using the picture-enhancing software. The reference traces associated with forehead inclinations were utilized to assess the anteroposterior (AP) positions of the maxillary central incisors. The results showed that a round forehead was the dominant forehead shape for Tibetan (93%) and Han (55%) Chinese females. In Tibetan females, 85% of the maxillary central incisors were found to be located between the forehead's anterior limit line (the Gall line) and the goal anterior limit line (the Fall line), with 15% located posterior to the Fall line. This distribution manifested a strong association with incisor position and forehead inclination (R2 = 0.742). In Han females, 83% of the maxillary central incisors were located between the Fall line and the Gall line, with 12% posterior to the Fall line and 5% anterior to the Gall line. The positions of the maxillary central incisors exhibited a strong relationship with forehead inclination (R2 = 0.827). The maxillary central incisors were close to the aesthetic line in both ethnic groups, while forehead inclinations were correlated with AP maxillary incisor position. These findings demonstrated that there was a close relationship between the incisor position of Tibetan and Han females with facial symmetry and the forehead FFA factor, indicating a reference in oral hard and soft tissues for optimizing orthodontic diagnosis and treatment planning in terms of facial contour.

Biodistribution and Absorption of Radiopharmaceutical 99mTc MDP in Various Bones of Lung Cancer Patients Using SPECT/CT Modalities

Lung-to-bone cancer metastasis frequently involves bone lesions, particularly in the vertebrae. A bone scan using the radiopharmaceutical 99mTc MDP is a common diagnostic tool for detecting advanced metastases. This research aimed to determine the conversion factor of count rate to unit activity, assess the range of source activity in bones with and without lesions, and analyze the relationship between lung cancer metastasis and radiopharmaceutical activity in various bones. The study involved 28 patients. Procedures included phantom manufacturing, determining the depth of Antero Posterior (AP) and Postero Anterior (PA) position bones, converting count rates to activity units, and assessing 99mTc MDP biodistribution in bones. Results indicated that the conversion factor of count rate to activity units in AP and PA positions for lumbar vertebrae, costa vera, ilium, and sacrum were (〖13.2×10〗^(-4); 4.9〖×10〗^(-4)) mCi/cps; (4.0〖×10〗^(-4); 4.4〖×10〗^(-4)) mCi/cps; (4.0〖×10〗^(-4); 4.9〖×10〗^(-4)) mCi/cps; and (〖12.2×10〗^(-4); 〖4.5×10〗^(-4)) mCi/cps. In addition, there is a range of source activity values and percentage of activity in the bones (lumbar vertebrae; costa vera; ilium; and sacrum), namely (0.019-0.053) mCi and (0.107-0.498)%; (0.020-0.045) mCi and (0.139-0.338)%; (0.024-0.066) mCi and (0.128-0.551)%; and (0.012-0.028) mCi and (0.078-0.264)%. Furthermore, there is a range of source activity values in the lesion-indicated bone (lumbar vertebrae; costa vera; ilium; and sacrum), namely (0.038-0.053) mCi; (0.024-0.045) mCi; (0.033-0.066) mCi; and (0.017-0.028) mCi. The relationship between lung cancer metastasis to various bones studied and the range of radiopharmaceutical activity values obtained is moderately positive.