Lateral Translation Research Articles

Lensless super-resolved quantitative phase imaging with cm-level lateral translations of two glass plates.

In this Letter, we propose a new, to the best of our knowledge, lensless on-chip holographic microscopy platform, which can acquire sub-pixel-shifting holograms through centimeter (cm)-level lateral translations. An LED light source is used to illuminate the sample, and two orthogonally tilted step-structure glass plates are inserted into the optical path. By merely displacing the glass plates under cm-level precision, a series of holograms with sub-pixel displacements can be obtained. Combined with our improved pixel super-resolution (PSR) algorithm, high-quality PSR phase imaging can be achieved. Tests on the high-resolution USAF1951 target demonstrate that the system can achieve a half-width resolution of 870 nm by a camera with a pixel size of 1.67 µm. Additionally, imaging experiments were conducted on phase-type sinusoidal gratings, yeasts, red blood cells, and lilium ovary sections, respectively. The results show that the system can achieve large field-of-view, high-resolution phase imaging under low-cost hardware conditions and holds promise for its applications in biology and medicine.

Is suture-based cerclage biomechanically superior to traditional metallic cerclage for fixation of periprosthetic femoral fractures: A matched pair cadaveric study

BackgroundWhile traditional metallic cerclage remains the primary method in clinical application, non-metallic cerclage systems have recently gained popularity due to low risks of soft tissue irritation and bone intrusion. The objective of this study was to assess the performance of a novel non-metallic suture-based cerclage in comparison to traditional metallic cerclage cables for fixation of periprosthetic femoral fractures. MethodsAn extended trochanteric osteotomy was performed on eight pairs of cadaveric femora, followed by reduction using either metallic cerclages (Group I) or the suture-based cerclage (Group II). A modular tapered fluted stem was then implanted in each specimen. The fragment translation during canal preparation and stem implantation was quantified using laser-scanning. Subsequently, each specimen underwent 500 cycles of multiaxial loading, with fragment translation and stem subsidence measured using a motion capture system. FindingsFollowing stem implantation, specimens in Group II exhibited a significantly greater lateral fragment translation (466 μm vs 754 μm, p = 0.017). However, there were no significant differences in anterior and distal translation between groups (p > 0.05). During multiaxial loading, the average stem subsidence in Group I was 0.36 mm (range, 0.04–1.42 mm), compared to 0.41 mm (range, 0.03–1.29) in Group II (p > 0.05). No significant difference was found in fragment translations between the two groups (p > 0.05). InterpretationThe suture-based cerclage system exhibited comparable biomechanical performance in fixation stability to conventional metallic cerclage cables. Yet, it was associated with a larger residual lateral gap between the fragments following stem implantation. Ultimately, the choice of fixation method should account for multiple factors, including patient characteristics, surgeon preference, and bone quality.

New findings on clinical experience on surface-guided radiotherapy for frameless non-coplanar stereotactic radiosurgery treatments.

The aim of this study was to assess the accuracy of a surface-guided radiotherapy (SGRT) system for setup and intra-fraction motion control in frameless non-coplanar stereotactic radiosurgery (fSRS) using actual patient data immobilized with two different types of open-faced masks and employing a novel SGRT systems settings. Forty-four SRS patients were immobilized with two types of open-faced masks. Sixty lesions were treated, involving the analysis of 68 cone-beam scans (CBCT), 157 megavoltage (MV) images, and 521 SGRT monitoring sessions. The average SGRT translations/rotations and 3D vectors (MAG-Trasl and MAG-Rot) were compared with CBCT or antero-posterior MV images for 0° table or non-coplanar beams, respectively. The intrafraction control was evaluated based on the average shifts obtained from each monitoring session. To assess the association between the SGRT system and the CBCT, the two types of masks and the 3D vectors, a generalized estimating equations (GEE) regression analysis was performed. The Wilcoxon singed-rank test for paired samples was performed to detect differences in couch rotation with longitudinal (LNG) and lateral (LAT) translations and/or yaw. The average SGRT corrections were smaller than those detected by CBCT (≤0.5mm and 0.1°), with largest differences in LNG and yaw. The GEE analysis indicated that the average MAG-Trasl, obtained by the SGRT system, was not statistically different (p=0.09) for both mask types, while, the MAG-Rot was different (p=0.01). For non-coplanar beams, the Wilcoxon singed-rank test demonstrated no significantly differences for the corrections (LNG, LAT, and yaw) for any table rotation except for LNG corrections at 65° (p=0.04) and 75° (p=0.03) table angle position; LAT shifts at 65° (p=0.03) and 270° (p<0.001) table angle position, and yaw rotation at 30° (p=0.02) table angle position. The average intrafraction motion was<0.1mm and 0.1° for any table angle. The SGRT system used, along with the novel workflow performed, can achieve the setup and intra-fraction motion control accuracy required to perform non-coplanar fSRS treatments. Both masks ensure the accuracy required for fSRS while providing a suitable surface for monitoring.

Design and Validation of an Ambulatory User Support Gait Rehabilitation Robot: NIMBLE

Relearning to walk requires progressive training in real scenarios—overground—along with assistance in basic tasks, such as balancing. In addition, user ability must be maximized through compliant robotic assistance as needed. Despite decades of research, gait rehabilitation robotic devices yield controversial results. This article presents the conceptual design of a novel walking assistance and rehabilitation robot, the NIMBLE robot, aimed at providing ambulatory, bodyweight-supported gait training, assisting the user’s center of mass trajectory to aid weight transfer and dynamic balance during walking. NIMBLE consists of a robotic mobile frame, a partial bodyweight support (PBWS) system, an ambulatory lower-limb exoskeleton (Exo-H3) and a cable-driven pelvis-assisting robot. Designed as a modular structure, it differentiates hierarchical communication levels through a Robot Operating System (ROS) 2 network. We present the mechatronic design and experimental results assessing the impact of the mechatronic coupling between the robotic modules on the walking kinematics and the frame movement control performance. The robotic frame hardly affects the walking kinematics up to 2 degrees in both the sagittal and frontal planes, making it feasible for lateral balance and weight translation training. Moreover, it successfully tracks and follows user trajectories. The NIMBLE robotic frame assessment shows promising results for ambulatory gait rehabilitation.

Evaluation of Load on Cervical Disc Prosthesis by Imposing Complex Motion: Multiplanar Motion and Combined Rotational-Translational Motion.

(1) Background: The kinematic characteristics of disc prosthesis undergoing complex motion are not well understood. Therefore, examining complex motion may provide an improved understanding of the post-operative behavior of spinal implants. (2) Methods: The aim of this study was to develop kinematic tests that simulate multiplanar motion and combined rotational-translational motion in a disc prosthesis. In this context, five generic zirconia-toughened alumina (BIOLOX®delta, CeramTec, Germany) ball and socket samples were tested in a 6 DOF spine simulator under displacement control with an axial compressive force of 100 N in five motion modes: (1) flexion-extension (FE = ± 7.5°), (2) lateral bending (LB = ± 6°), (3) combined FE-LB (4) combined FE and anteroposterior translation (AP = 3 mm), and (5) combined LB and lateral motion (3 mm). For combined rotational-translational motion, two scenarios were analyzed: excessive translational movement after sample rotation (scenario 1) and excessive translational movement during rotation (scenario 2). (3) Results: For combined FE-LB, the resultant forces and moments were higher compared to the unidirectional motion modes. For combined rotational-translational motion (scenario 1), subluxation occurred at FE = 7.5° with an incremental increase in AP translation = 1.49 ± 0.18 mm, and LB = 6° with an incremental increase of lateral translation = 2.22 ± 0.16 mm. At the subluxation point, the incremental increase in AP force and lateral force were 30.4 ± 3.14 N and 40.8 ± 2.56 N in FE and LB, respectively, compared to the forces at the same angles during unidirectional motion. For scenario 2, subluxation occurred at FE = 4.93° with an incremental increase in AP translation = 1.75 mm, and LB = 4.52° with an incremental increase in lateral translation = 1.99 mm. At the subluxation point, the incremental increase in AP force and lateral force were 39.17 N and 38.94 N in FE and LB, respectively, compared to the forces in the same angles during the unidirectional motion. (4) Conclusions: The new test protocols improved the understanding of in vivo-like behavior from in vitro testing. Simultaneous translation-rotation motion was shown to provoke subluxation at lower motion extents. Following further validation of the proposed complex motion testing, these new methods can be applied future development and characterization of spinal motion-preserving implants.

Probabilistic ultimate lateral capacity of two-pile groups in spatially random clay

ABSTRACT The undrained lateral capacity of a group of two side-by-side piles has been studied in uniform clay, but the effect of spatial variability in clay strength on lateral pile capacity remains unclear. This paper describes probabilistic ultimate lateral capacity for two circular piles in spatially variable undrained clay. An adaptive finite element limit analysis based on random field generation combined with Monte Carlo simulations is applied. The lateral capacity statistics of two-pile groups with different combinations of pile spacings and pile roughness are presented. It is found that the consideration of the random nature of clay strength leads to a significant decrease in the lateral pile capacity, especially at a pile spacing approximately equal to the pile diameter. The factor of safety required to attain a target probability of failure is provided as a function of pile spacing. The obtained results give guidance for the reliability-based design of laterally-loaded two-pile groups in spatially varied clay and can also be applicable for understanding the lateral translation of two interfering cables and pipelines deeply buried in random clay.

Treatment Reproducibility in Brain Stereotactic Radiotherapy Using a Shim Mask Versus a Standard Mask.

Introduction This study aimed to evaluate the setup accuracy of the new shim mask with mouth bite compared to the standard full brain mask in stereotactic radiosurgery (SRS) and radiotherapy (SRT) treatments for brain metastases or tumors. Method A combined retrospective and prospective design was employed, involving 40 patients treated at our center. Patients previously treated using standard head masks formed the retrospective cohort, while those treated with the Shim mask and mouth bite formed the prospective cohort. Daily cone-beam computed tomography (CBCT) scans were obtained before each treatment session to ensure patient setup accuracy. Key metrics included absolute shifts in translational and rotational directions, the number of repeat CBCTs, and the time interval between CBCTs. Results The Shim mask significantly reduced the mean setup errors in the lateral translation (p=0.022) from 0.17 cm (SD=0.10) to 0.10 cm (SD=0.10), and in X-axis rotation (p=0.030) from 0.79° (SD=0.43) to 0.47° (SD=0.47). By considering cutoff points of 1 mm in translational and 1° in rotational directions, the Shim mask was significantly more accurate in the lateral direction (p=0.004). Moreover, while 70% of patients in the standard group required repeat CBCT scans, none in the Shim group did, resulting in an average time saving of 10.4 minutes per patient. Conclusion The Shim mask with mouth bite offers enhanced immobilization accuracy in SRT/SRS treatments, leading to time and potential cost savings by reducing the need for repeat CBCT scans. This underscores the importance of adopting innovative immobilization techniques to optimize patient outcomes.

A Cadaveric Study: Does Ankle Positioning Affect the Quality of Anatomic Syndesmosis Reduction?

The objective of this study was to compare the quality of syndesmotic reduction with the ankle in maximal dorsiflexion versus neutral plantarflexion (normal resting position). Baseline computed tomography (CT) imaging of 10 cadaveric ankle specimens from 5 donors was obtained with the ankles placed in normal resting position. Two fellowship-trained orthopaedic surgeons disrupted the syndesmosis of each ankle specimen. All ankles were then placed in neutral plantarflexion and were subsequently reduced with thumb pressure under direct visualization through an anterolateral approach and stabilized with one 0.062-inch K-wire placed from lateral to medial in a quadricortical fashion across the syndesmosis. Postreduction CT scans were then obtained with the ankle in normal resting position. This process was repeated with the ankles placed in maximal dorsiflexion during reduction and stabilization. Postreduction CT scans were then obtained with the ankles placed in normal resting position. All postreduction CT scans were compared with baseline CT imaging using mixed-effects linear regression with significance set at P < 0.05. Syndesmotic reduction and stabilization in maximal dorsiflexion led to increased external rotation of the fibula compared with baseline scans [13.0 ± 5.4 degrees (mean ± SD) vs. 7.5 ± 2.4 degrees, P = 0.002]. There was a tendency toward lateral translation of the fibula with the ankle reduced in maximal dorsiflexion (3.3 ± 1.0 vs. 2.7 ± 0.7 mm, P = 0.096). No other statistically significant differences between measurements of reduction with the ankle placed in neutral plantarflexion or maximal dorsiflexion compared with baseline were present (P > 0.05). Reducing the syndesmosis with the ankle in maximal dorsiflexion may lead to malreduction with external rotation of the fibula. There was no statistically significant difference in reduction quality with the ankle placed in neutral plantarflexion compared with baseline. Future studies should assess the clinical implications of ankle positioning during syndesmotic fixation.

Open wedge high tibial osteotomy alters patellofemoral joint kinematics: A multibody simulation study.

Changes in lower limb alignment after open-wedge high tibial osteotomy (owHTO) influence joint kinematics. The aim of this study was to investigate the morphological and kinematic changes of the knee joint, in particular the patellofemoral joint, using a multibody simulation model. OwHTO with an open tibial wedge of 6-12 mm (1 mm intervals) was virtually performed on each of 13 three-dimensional (3D) computer-aideddesign models (CAD models) derived from computer tomography scans of full-leg cadaver specimens. For each owHTO, an individual biomechanical simulation model was built and knee flexion from 5° to 100° was simulated using a multibody simulation model of the native knee. Morphologic and alignment parameters as well as tibiofemoral and patellofemoral kinematic parameters were evaluated. Almost linear changes in tibial tuberosity trochlea groove(TT-TG) (0.42 mm/1 mm wedge height) were observed which led to pathological values (TT-TG > 20 mm) in 3 out of 13 knees. Furthermore, a 6 mm increase in osteotomy wedge height increased lateral patellofemoral rotation by 0.8° (range: 0.39° to 1.11°) and led to a lateral patellar translation of 0.8 mm (range: 0.37-3.11 mm) on average. Additionally, valgisation led to a medial translation of the tibia and a decrease in the degree of tibial internal rotation during knee flexion of approximately 0.3°/1 mm increase in osteotomy wedge height. The increase in TT-TG and the biomechanical effects observed influence patellofemoral tracking, which may increase retropatellar pressure and are potential risk factors for the development of anterior knee pain.

Poster 197: A 3D Analysis of Hip Center of Rotation Trajectory and its Effects on Impingement-Free Range of Motion: A Dynamic Analysis of 1222 Hips

Objectives: Traditionally, the hip has been thought of as a particularly stable ball and socket joint with a fixed center of rotation and no translation. This view has been the basis for several simulation platforms studying hip impingement and instability for treatment planning and outcome analyses. More recently, in vivo imaging and cadaveric studies have suggested that, in addition to rotation, the femoral head and center of rotation (COR) translate within the joint throughout physiologic range of motion. A recent MRI study has shown an average translation of 2 mm, with up to 7 mm translations in certain positions, among subjects with asymptomatic hips. Importantly, substantial magnitudes of translation can alter hip contact and impingement patterns with downstream effects on the treatment planning and patient outcomes. However, there is a paucity of literature regarding how hip translation may influence hip impingement. Therefore, the purpose of this study was to use a validated simulation platform, capable of simulating hip translation during impingement analysis, to map the trajectory of the hip COR and its effects on impingement-free hip range of motion (ROM). Methods: Following institutional review board approval, the New Mexico Decedent Image Database (NMDID) was queried to identify computed tomography scans with full coverage of the hip and femur from subjects with no documented bone and joint pathology (n = 1222 hips, 611 patients, age: 30.4 ± 8.8; 67% male patients). A custom-developed and validated program (VirtualHip, Boston Children’s Hospital) was used to automatically segment the bones, identify landmarks (Dice 0.94 – 0.99), and define an anatomical coordinate system based on International Society of Biomechanics (ISB) recommendations. The pelvis was then fixed in 3D and the femur was moved to simulate uniplanar rotations (ie, flexion: 0° to 150°, extension: 0° to 50°, abduction/adduction: 0° to 75°, internal /external rotations: 0° to 75°). The simulations were first done assuming a fixed hip COR (no translation) and then repeated by incrementally allowing the hip COR to translate by up to 5 mm with increments of 1 mm, avoiding bone-to-bone penetration or hip dislocation (distance between the femoral head and acetabulum exceeding the joint space width measured at neutral). Mixed linear models were used to evaluate the relationships between COR translation and impingement-free rotation (maximum rotation prior to impingement). The effect of translation on ROM was characterized by calculating the proportion of hips able to achieve each ROM. Finally, the path of the hip COR was mapped throughout the tested ranges of motion. Results: The effect of COR translation on achieved impingement-free range of motion along with COR trajectories are shown in Figure 1. Hip flexion was associated with COR posterior (by 4.0 ± 0.9 mm), lateral (only after 100°, by 3.6 ± 1.4 mm), and superior (only after 100°, by 2.0 ± 1.8 mm) translations (P &lt; 0.001). Hip extension was only associated with anterior COR translation (by 0.8 ± 0.7 mm, P &lt; 0.001). Hip adduction was associated with anterior (by 2.9 ± 1.3 mm), lateral (by 4.0 ± 1.3 mm), and superior (by 4.4 ± 0.6 mm) translations (P&lt;0.01). Hip abduction was only associated with medial (by 2.6 ± 1.5 mm) and inferior (by 2.9 ± 1.7 mm) translations (P &lt; 0.02). There were minimal COR translations during hip internal rotation (P &gt; 0.05). Hip external rotation was associated with anterior (by 3.7 ± 1.4 mm) and inferior (by 1.2 ± 1.3 mm) translations (P &lt; 0.05). Conclusions: This is the first study to map the hip COR trajectory under common movements in a large cohort of patients. The current findings highlight the importance of hip translation (nonfixed COR) on physiologic hip range of motion. As the hip is not a perfect ball and socket joint, with an aspherical femoral head, translation is required to accommodate physiologic rotation (ie, glide mechanism) without bony impingement between the femur and pelvis. These preliminary observations highlight the need for a comprehensive assessment of normal and pathologic hip translation along with their role in biomechanics, injury risk, and response to treatment. A clear understanding of the role of hip translation in hip function and health will improve clinical care through better diagnosis and personalized treatment planning, which can ultimately lead to improved treatment outcomes, particularly lower risk of osteoarthritis. [Figure: see text]

STTAR: Surgical Tool Tracking Using Off-the-Shelf Augmented Reality Head-Mounted Displays.

The use of Augmented Reality (AR) for navigation purposes has shown beneficial in assisting physicians during the performance of surgical procedures. These applications commonly require knowing the pose of surgical tools and patients to provide visual information that surgeons can use during the performance of the task. Existing medical-grade tracking systems use infrared cameras placed inside the Operating Room (OR) to identify retro-reflective markers attached to objects of interest and compute their pose. Some commercially available AR Head-Mounted Displays (HMDs) use similar cameras for self-localization, hand tracking, and estimating the objects' depth. This work presents a framework that uses the built-in cameras of AR HMDs to enable accurate tracking of retro-reflective markers without the need to integrate any additional electronics into the HMD. The proposed framework can simultaneously track multiple tools without having previous knowledge of their geometry and only requires establishing a local network between the headset and a workstation. Our results show that the tracking and detection of the markers can be achieved with an accuracy of 0.09±0.06 mm on lateral translation, 0.42 ±0.32 mm on longitudinal translation and 0.80 ±0.39° for rotations around the vertical axis. Furthermore, to showcase the relevance of the proposed framework, we evaluate the system's performance in the context of surgical procedures. This use case was designed to replicate the scenarios of k-wire insertions in orthopedic procedures. For evaluation, seven surgeons were provided with visual navigation and asked to perform 24 injections using the proposed framework. A second study with ten participants served to investigate the capabilities of the framework in the context of more general scenarios. Results from these studies provided comparable accuracy to those reported in the literature for AR-based navigation procedures.

Study on seismic performance of SRC frame-bent structures in CAP1400 nuclear power plants

With the conventional island turbine plant project of a CAP1400 nuclear power plant (NPP) as the research background, this paper proposed to apply steel reinforced concrete (SRC) frame-bent structure system to the main building of the NPP. Substructures comprising three frames and two spans from the prototype structure were identified for testing, and a test model was constructed at a scale ratio of 1/7 to test the dynamic and pseudo-dynamic characteristics of the substructures. On the basis of the test results, the structure was further verified using the finite element analysis method. The results showed that the first three modes of substructure were respectively lateral translation with torsion, longitudinal translation with torsion and torsion; The ratio between the third-order and first-order mode cycles was 0.72, indicating that the torsional stiffness of the structure was relatively small and the torsional effect was obvious. When the maximum acceleration peak was 2200 gal, the maximum inter-story drift ratio of the model structure reached 1/31. Ultimately, when the structure was finally destroyed, the concrete at the bottom of each SRC column was crushed and peeled off.

Temporal changes in tibiofemoral relationship following anterior cruciate ligament injury: Implications for rotational dynamics and clinical outcomes.

This study aims to elucidate changes in the tibiofemoral relationship over time following anterior cruciate ligament (ACL) injury, and investigate the correlation between the tibiofemoral relationship and patient-related outcome measures (PROMs). Overall, 203 primary ACL reconstructions were performed using autologous hamstring grafts. Medial and lateral anterior tibial translation (ATT) in the sagittal plane and tibial tubercle-trochlear groove (TT-TG) distance in the axial plane were measured using pre-operative magnetic resonance imaging and post-operative computed tomography. The difference between pre-operative and post-operative values for each parameter was calculated: ΔMesdial ATT, ΔLateral ATT and ΔTT-TG distance. The correlation between each calculated value and the time elapsed since ACL injury, and the correlation between each calculated value and PROMs-evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS)-were assessed. Sixty-four patients were enroled. Medial ATT, lateral ATT and TT-TG distance were significantly different pre-operatively compared to post-operative values, with the tibia translating anteriorly and rotating internally relative to the femur. ΔMedial ATT, ΔLateral ATT and ΔTT-TG distance were 1.6, 8.8 and -4.8 mm, respectively. A negative correlation was observed between the ΔTT-TG distance and the time elapsed since the injury (r = -0.44, p < 0.01). No correlation was found between ΔMedial ATT and the time elapsed since the injury, nor between ΔLateral ATT and the time elapsed since the injury. Neither the ΔMedial ATT, ΔLateral ATT, nor ΔTT-TG distance correlated with the pre-operative or post-operative KOOS subscale scores. The tibia underwent internal rotation relative to the femur over time following ACL injury, highlighting the importance of assessing rotational changes in ACL-injured knees. Level Ⅲ.

Computerized Axiographic Findings in a Cohort of Migraine Patients: A Cross-Sectional Study.

The objective of this work was to investigate the association between the function of the stomatognathic system and migraine presence through an instrumental functional analysis in a group of diagnosed migraine patients and a control group. This study included 50 individuals in each group. A jaw-tracking analysis was performed using Cadiax 4. Tracings of the following movements were recorded: open/close, protrusion/retrusion, mediotrusion, speech, bruxing, and mastication. The tracings were evaluated for their quantity, quality, transversal characteristics, speed, curvature pattern, and condylar stability. Statistically significant differences between the groups were established for several aspects of the evaluation. Migraineurs presented with (a) higher values of mandibular lateral translation in protrusion/retrusion (p = 0.001), open/close (p = 0.031), and mastication (p = 0.016); (b) transient velocity losses in open/close (p = 0.001) and protrusive movements (p = 0.018); (c) a compromised condylar stability for protrusion/retrusion (p = 0.001) and mediotrusion (p = 0.003); (d) a compromised quality for protrusion/retrusion (p < 0.001) and mediotrusion (p = 0.003); and (e) a more frequent "figure-eight" curvature in open/close (p = 0.012). The importance of the stomatognathic function in migraine pathogenesis and treatment should be considered by using a patient-centered and interdisciplinary approach.

Spontaneous Reduction in the Intermetatarsal Angle in Distal First Metatarsal Osteotomies with No Lateral Head Displacement in Hallux Valgus.

The outcomes of first metatarsal (M1) distal osteotomies in hallux valgus (HV) can be improved, especially for intermetatarsal angle (IMA) correction, which is mainly based on lateral displacement of the M1 head (i.e., translation) through the osteotomy. Conversely, there is a spontaneous reduction in the IMA in first metatarsophalangeal joint (MTP1) arthrodesis. But we do not know whether this can be applied to distal osteotomies. We propose a distal osteotomy, called 3D chevron, which combines supination and varization of the M1 head. This might realign soft tissues around the MTP1, potentially leading to a spontaneous reduction in the IMA by an analogous mechanism to MTP1 fusion. Therefore, our study aimed to assess whether spontaneous reductions in IMAs exist in distal M1 osteotomies in the absence of lateral translations of M1 heads. A prospective continuous series of 25 3D chevrons was performed. Two groups were formed during surgery. Patients requiring no M1 head lateral displacement were included in the "successful correction without translation" group, and patients requiring M1 head lateral displacement were included in the "failed correction without translation" group. Radiographic analysis was performed preoperatively and at 1 year postoperatively. Twenty-two women and three men, with a mean age of 44.8 ± 14.2 years and a mean body mass index of 22.6 ± 4.1 kg/m2, underwent follow-up at one year after surgery. The "successful correction without translation" group was composed of HV with milder deformities (13/25 HVs, median preoperative IMA = 13 (IQR 2)) compared to the "failed correction without translation" group (median IMA = 16 (IQR 2.25) p < 0.001). Spontaneous reductions in IMAs were observed in the "successful correction without translation" group, with a median decrease in the IMA of 6 degrees (CI95%[5.5; 8.0]; p < 0.001) between preoperative and 1-year radiographs. Distal osteotomies allow for spontaneous reduction in the IMA in HV. First metatarsal head translation through an osteotomy should not be considered as the only procedure to correct IMAs in distal osteotomies.

Three different patellar fixation techniques yield similar clinical and radiological outcomes in recurrent patellar dislocation undergoing medial patellofemoral ligament reconstruction.

The purpose of this study was to evaluate and compare the clinical and radiological outcomes of three different patellar fixation techniques on medial patellofemoral ligament reconstruction (MPFLR) in the treatment of patellar dislocation (PD). Between 2015 and 2020, 130 patients with recurrent PD who underwent surgical reconstruction were eligible for this retrospective study: 48 patients were treated with the semi-tunnel bone bridge fixation technique (Group A), 42 patients were treated with the suture anchor fixation technique (Group B) and 40 patients were treated with the transpatellar tunnel fixation technique (Group C). Clinical outcomes included functional outcomes (Kujala, Lysholm and International Knee Documentation Committee scores), activity levels (Tegner activity score and return to sports), physical examinations, patellar re-dislocation rate and complications. Radiological outcomes included patellar congruence angle, patellar tilt angle, lateral patellar translation and lateral patellar angle. All clinical and radiological outcomes improved significantly in all groups, without any significant difference among these three groups. At the final follow-up, no re-dislocation occurred, and all groups achieved a successful return to sports. However, the semi-tunnel bone bridge and suture anchor fixation techniques showed statistically higher Tegner activity scores (p = 0.004) and shorter time from surgery to return to sports (p = 0.007) than the transpatellar tunnel fixation technique. The three MPFLR patellar fixation techniques achieved favourable and comparable clinical and radiological outcomes in the treatment of PD. Compared with the transpatellar tunnel fixation technique, the semi-tunnel bone bridge and suture anchor fixation techniques may be more effective with higher activity levels. Level III.

Effect of Medial Patellofemoral Complex Reconstruction Technique on Patellofemoral Contact Pressure, Contact Area, and Kinematics.

Medial patellofemoral ligament (MPFL) reconstruction is considered by many to be the gold standard to treat lateral patellar instability; however, some investigators have reported good clinical results after isolated medial quadriceps tendon-femoral ligament (MQTFL) reconstruction or a combined MPFL/MQTFL reconstruction. A handful of studies have preliminarily investigated the biomechanical consequences of these various medial patellar stabilizing procedures. Despite this, no existing study has included multiple medial patellofemoral complex (MPFC) reconstructions and assessment of lateral patellar translation at distinct flexion angles. Combined MPFL/MQTFL reconstruction would restore patellofemoral contact areas, forces, and kinematics closest to the native state compared with isolated reconstruction of the MPFL or MQTFL alone. Controlled laboratory study. Ten adult cadaveric knee specimens were prepared and analyzed under 5 different conditions: (1) intact state, (2) transected MPFC, (3) isolated MPFL reconstruction, (4) isolated MQTFL reconstruction, and (5) combined MPFL/MQTFL reconstruction. Patellar tilt, lateral patellar translation, patellofemoral contact forces, and patellofemoral contact areas were measured in each condition from 0° to 80° through simulated knee flexion using a custom servohydraulic load frame with pressure sensor technology and a motion capture system for kinematic data acquisition. The isolated MPFL, isolated MQTFL, and combined MPFL/MQTFL reconstruction conditions produced significantly less lateral patellar tilt compared with the transected MPFC state (P < .05). No statistically significant differences were found when each reconstruction technique was compared with the intact state in patellar tilt, lateral patellar translation, contact forces, and contact areas. All 3 reconstruction techniques (isolated MPFL reconstruction, isolated MQTFL reconstruction, and combined MPFL/MQTFL reconstruction) restored native knee kinematics, contact forces, and contact areas without overconstraint. Isolated MPFL reconstruction, isolated MQTFL reconstruction, and combined MPFL/MQTFL reconstruction all restore patellofemoral stability comparable with the intact MPFC state without the overconstraint that could be concerning for increasing risk of patellofemoral arthritis.

EFFECT OF FIBULA SHORTENING ON MEDIAL CLEAR SPACE AND LATERAL TRANSLATION OF THE TALUS: AN ANATOMICAL CADAVERIC STUDY

IntroductionFibula shortening with an intact anterior tibiofibular ligament (ATFL) and medial ligament instability causes lateral translation of the talus. Our hypothesis was that the interaction of the AITFL tubercle of the fibular with the tibial incisura would propagate lateral translation due to the size differential.AimTo assess what degree of shortening of the fibular would cause the lateral translation of the talus.MethodologyTwelve cadaveric ankle specimens were dissected removing all soft tissue except for ligaments. They were fixed on a specially-designed platform within an augmented ankle cage allowing tibial fixation and free movement of the talus. The fibula was progressively shortened in 5mm increments until complete ankle dislocation. The medial clear space was measured with each increment of shortening.ResultsThe larger AITFL tubercle interaction with the smaller tibial incisura caused a significant increase in lateral translation of the talus. This occurred in most ankles between 5–10mm of fibular shortening. The medial clear space widened following 5mm of shortening in 5 specimens (mean=2.0725, SD=±2.5338). All 12 specimens experienced widening by 10mm fibula shortening (Mean=7.2133mm, SD=±2.2061). All specimens reached complete dislocation by 35mm fibula shortening. Results of ANOVA analysis found the data statistically significant (p&lt;0.0001).ConclusionThis study shows that shortening of the fibula causes a significant lateral translation of the talus provided the ATFL remains intact. Furthermore, the interaction of the fibula notch with the ATFL tubercle of the tibia appears to cause a disproportionate widening of the medial clear space due to its differential in size. Knowledge of the extent of fibula shortening can guide further intervention when presented with a patient experiencing medial clear space widening following treatment of an ankle fracture.

Utility of a Neuromuscular Activation Exercise Protocol on Surgeon Posture.

Surgeons are at risk for musculoskeletal disorders from ergonomic strain in the operating room. These deficits may stem from neuromuscular control deficits. Neuromuscular activation exercises (NMEs) may strengthen the brain-muscle connection. This study aimed to assess the utility of a surgeon-oriented NME protocol on posture. Surgeons, operating room staff, and medical students completed a professionally established NME routine. An electronic application, PostureScreen®, assessed participants' posture. A long-term cohort was assessed before and after a 2 to 6-week routine. A short-term cohort was assessed immediately before and after completion. All participants additionally completed a postintervention survey. After intervention, the short-term cohort (n = 47) had significantly reduced frontal and sagittal postural deviation (P < 0.05). A significant decrease in effective head weight was additionally demonstrated with decreased neck flexion and increased cerebral-cervical symmetry (P < 0.05).The long-term cohort (n = 6) showed a significant postintervention decrease in lateral and anterior shoulder translation (P < 0.05). Total anterior translational deviations demonstrated trend-level decrease (P = 0.078). This demonstrates that after intervention, participants' shoulders were more centered with the spine as opposed to shifted right or left. Survey results showed participants favored exercises that immediately brought relief of tension. A decrease in postural deviations associated with NME in both cohorts demonstrates NME as a potential mechanism to protect surgeon musculoskeletal health and improve well-being. Survey results demonstrate areas of refinement for NME protocol design.

Trochlea Dysplasia as the Major Anatomic Risk Factors for Patellofemoral Joint Instability: An Infographic as a Visual Learning Tool.

Patellofemoral instability (PFI) is a common condition in children and adolescents, ranging from mild discomfort and mal-tracking to lateral patellar dislocation [1]. A number of anatomical risk factors have been described in the literature, such as trochlear dysplasia, patella alta, excessive tibial tuberosity to trochlear groove (TT-TG) distance, patellar tilt and soft tissue alterations [2]. Among them, TD has been identified as the main anatomical risk factor with the strongest association with PFI [1, 2]. In the study by Dejour et al. [2] radiographically observed TD was identified in 96% of patients with a history of patellofemoral dislocation [1, 2]. Patients with Dejour Type D dysplasia are characterized by a prominent and convex lateral facet with a vertical connection to a hypoplastic medial facet (Figure 1), which provides inadequate tracking of the patella in the trochlea during flexion leading to patella subluxation [2]. Non-operative treatment of lateral patellar dislocation presents a rate of re-dislocation up to 70% within 24 months of the first episode [3]. Sulcus deepening trochleoplasty is indicated for Type B and D dysplasia, in order to improve patella tracking, reduce the rate of re-dislocation and achieve good functional outcomes [2, 4]. Trochlea dysplasia is defined as a shallow or flattened groove with decreased resistance to lateral patellar translation. TD can be assessed on computed tomography (CT) and magnetic resonance imaging (MRI) with the use of overlapping axial images and are able to show perfectly the global shape of the femoral trochlea [2]. The thresholds for identifying trochlear dysplasia are established based on the sulcus angle ≥ 145°, medial/lateral trochlea facet asymmetry < 40%, trochlear depth < 3 mm and lateral trochlear inclination ≤ 11° and therefore it can be used in young adolescents [4, 5]. A deep knowledge of anatomic variations and abnormalities of the patellofemoral joint, which may predispose to PFI, is crucial in order to choose the appropriate treatment for each patient.