A Prospective Randomized Controlled Trial Assessing the Impact of Preoperative Combined with Postoperative Progressive Resistance Training on Muscle Strength, Gait, Balance and Function in Patients Undergoing Total Hip Arthroplasty.

Purpose: The aim of this study is to investigate the effects of a preoperative combined with postoperative moderate-intensity progressive resistance training (PRT) of the operative side in patients with hip osteoarthritis (HOA) who are undergoing total hip arthroplasty (THA). The study seeks to evaluate the impact of this combined intervention on muscle strength, gait, balance, and hip joint function in a controlled, measurable, and objective manner. Additionally, the study aims to compare the outcomes of this combined intervention with those of preoperative or postoperative muscle strength training conducted in isolation. Methods: A total of 90 patients with HOA scheduled for unilateral primary THA were randomly assigned to three groups: Pre group (preoperative PRT), Post group (postoperative PRT), and Pre& Post group (preoperative combined with postoperative PRT) focusing on hip flexion, extension, adduction, and abduction of operated side. Muscle strength, gait parameters, balance, and hip function were assessed at specific time points during a 12-month follow-up period. Results: All three groups showed significant improvements in muscle strength, with the Pre& Post group demonstrating the most pronounced and sustained gains. Gait velocity and cadence were significantly improved in the Pre& Post group at 1-month and 3-month postoperative follow-ups compared to the other groups. Similarly, the Pre& Post group exhibited superior balance performance at 3-month and 12-month postoperative follow-ups. The Harris Hip Score also showed better outcomes in the Pre& Post group at all follow-up intervals. Conclusion: Preoperative combined with postoperative moderate-intensity PRT in HOA patients undergoing THA led to superior improvements in muscle strength, gait, balance, and hip joint function compared to preoperative or postoperative PRT alone. This intervention shows significant promise in optimizing postoperative rehabilitation and enhancing patient outcomes following THA.

Psoas force recruitment in full-body musculoskeletal movement simulations is restored with a geometrically informed cost function weighting.

Simulations of musculoskeletal models are useful for estimating internal muscle and joint forces. However, predicted forces rely on optimization and modeling formulations. Geometric detail is important to predict muscle forces, and greater geometric complexity is required for muscles that have broad attachments or span many joints, as in the torso. However, the extent to which optimized muscle force recruitment is sensitive to these geometry choices is unclear. We developed level, uphill and downhill sloped walking simulations using a standard (uniformly weighted, "fatigue-like") cost function with lower limb and full-body musculoskeletal models to evaluate hip muscle recruitment with different geometric representations of the psoas muscle under walking conditions with varying hip moment demands. We also tested a novel cost function formulation where muscle activations were weighted according to the modeled geometric detail in the full-body model. Total psoas force was less and iliacus, rectus femoris, and other hip flexors' force was greater when psoas was modeled with greater geometric detail compared to other hip muscles for all slopes. The proposed weighting scheme restored hip muscle force recruitment without sacrificing detailed psoas geometry. In addition, we found that lumbar, but not hip, joint contact forces were influenced by psoas force recruitment. Our results demonstrate that static optimization dependent simulations using models comprised of muscles with different amounts of geometric detail bias force recruitment toward muscles with less geometric detail. Muscle activation weighting that accounts for differences in geometric complexity across muscles corrects for this recruitment bias.

Deep squat test - Functional movement Screen: Convergent validity and ability to discriminate subjects with different levels of joint mobility.

BACKGROUND: Functional Movement Screen (FMS) is an important tool in the assessment of exercise practice. Assuming FMS lacks precise validity for assessing postural deficits, further research is needed to assess whether it is a sufficiently precise tool for analysing joint mobility. Research aims were to evaluate: convergent validity of Deep Squat (DS) - one of FMS tests - regarding joint mobility, using data from a three-dimensional motion analysis as a comparable method; DS's ability to discriminate between subjects with different joint mobility levels. METHODS: Sixty subjects were selected (23.6 ± 3.8 years). DS was performed according to FMS guidelines. Subjects' performance in frontal and sagittal planes was recorded by two video cameras and subsequently scored by two FMS-certified evaluators. Three-dimensional motion analyses of DS were acquired by a Vicon Motion Capture System (200 Hz). Ten trials were acquired for each subject. Ankle, knee, hip, and shoulder angular positions in sagittal plane were determined from the FullBody PlugInGait model. Spearman's coefficient examined the correlation between angular positions and DS score. Kruskal-Wallis test was used to assess the DS ability to discriminate between subjects with different joint mobility levels by comparing different scores. RESULTS: Negligible to moderate correlations were found between DS score and angular positions (-0.5 < r < 0.5). Only shoulder angular positions showed differences between score "1" and "2" (p < 0.05). Shoulder and hip angular positions showed no differences between score "2" and "3" (p < 0.05). CONCLUSIONS: DS yielded low convergent validity regarding joint mobility and did not show the ability to discriminate between subjects with different joint mobility levels.

What is the influence of biomechanical variables on the Y balance test performance in recreational runners?

BACKGROUND: Asymmetries and poor Y balance test (YBT) performance are associated with an increased risk of injuries in athletes. The aim of this study was to investigate the association between YBT performance with biomechanical variables in runners. METHODS: The runners underwent the YBT, followed by the assessment of center of pressure, plank position, muscle strength (MS) of hip flexors, extensors, abductors, and external rotators, knee extensors, ankle dorsiflexion range of motion (ROM), Q angle, forefoot alignment, and passive hip internal rotation. Associations between variables were examined using multiple linear regression models with the Bayesian Information Criterion. RESULTS: 122 cases were analyzed. The R2 values were 0.38; 0.05; 0.06; and 0.15 for the anterior, posteromedial, posterolateral and composite directions models, respectively. The anterior reach in the YBT was associated with ankle dorsiflexion ROM [Sß 95%IC: 0.43 (0.32-0.55)], passive hip internal rotation [Sß 95%IC: 0.35 (0.24-0.47)], MS of the hip extensors [Sß 95%IC: 0.19 (0.07-0.31)] and forefoot alignment [Sß 95%IC: 0.14 (-0.25-0.02)]. The posteromedial and posterolateral reach were associated with MS of the hip flexors [Sß 95%IC: 0.23 (0.09-0.37) and 0.24 (0.11-0.38)], respectively. The composite score was associated with MS of the hip flexors [Sß 95%IC: 0.31 (0.18-0.45)], ankle dorsiflexion ROM [Sß 95%IC: 0.24 (0.10-0.37)] and Q angle [Sß 95%IC: 0.18 (0.04-0.31)]. CONCLUSION: YBT performance in different directions demonstrated specific associations with key biomechanical factors.

Ankle dorsiflexion range of motion and hip abductor strength can predict Lower Quarter Y-Balance Test performance in healthy males.

OBJECTIVES: The aim of the study was to assess whether strength and range of motion (ROM) of the hip and ankle are the factors determining performance in the Lower Quarter Y-Balance test (YBT-LQ). DESIGN: Cross-sectional study. PARTICIPANTS: 66 healthy males (age: 25.2±6.8 years) participated in this study. MAIN OUTCOME MEASURES: Participants underwent assessments of ankle dorsiflexion (DF) ROM, hip internal rotation (IR) ROM, external rotation (ER) ROM and isometric strength of hip abductor (ABD), extensor (EXT) and external rotators (ERS) muscles together with YBT-LQ for both legs. A forward 2-steps multiple linear regression analysis was conducted to examine the relationship between the predictor variables and the criterion variable. RESULTS: Ankle DF ROM predicted anterior (ANT) reach (R2 = 0.49; R2 = 0.33; p < 0.001). The model with hip ABD strength and ankle DF ROM explained posteromedial (PM) reach variance for stance leg (R2 = 0.35; p < 0.001), while only hip ABD strength was included for kicking leg (R2 = 0.19; p = 0.007). The model with ankle DF ROM and hip ABD strength explained posterolateral (PL) reach for stance leg (R2 = 0.41; p < 0.001). Hip ABD was the only predictor for kicking leg PL reach (R2 = 0.15; p < 0.001). YBT-LQ composite score was explained by ankle DF ROM and hip ABD strength for both legs (R2 = 0.44; p < 0.001) and (R2 = 0.25; p = 0.002). CONCLUSION: Hip ABD strength and ankle DF ROM can determine performance in the YBT-LQ. Strength of hip EXT, ERS as well as ROM of hip IR and ER did not predict YBT-LQ performance.

The influence of gender and sport on popliteal angle and dorsiflexion in junior high school students.

BACKGROUND: The aim of the study was to assess factors affecting the popliteal angle and foot dorsiflexion, in particular gender. The subjects were 142 students from the 2nd and 3rd year of Poznan junior high schools. METHODS: The participants included 57 girls and 87 boys. Three raters examined each subject: a specialist in orthopaedics, a resident doctor and a physical therapy student. Foot dorsal flexion was tested in a supine position with lower limbs extended. Next, dorsal flexion was evaluated with the knee and hip in 90 degrees of flexion. Finally, a passive knee extension (PKE) test was carried out. The significance of the PKE test is that the lower the angle the more flexible the hamstrings. This is because the PKE measurement is the distance to the right angle, that is a full knee extension with the hip flexed. RESULTS: The non-parametric test (Mann-Whitney) and the Student's t-test showed differences between the female and male gender in the measurements of the popliteal angle (p < .05000). The correlation was negative, which means that the hamstrings are more flexible in girls. No differences were found between gender and passive foot dorsiflexion and dorsiflexion with a flexed hip and knee. No differences were found between the group with the extended PE curriculum and the group with the standard number of PE classes in the range of motion of foot dorsiflexion and the value of the popliteal angle. CONCLUSIONS: Girls between 13 and 15 years old have a significantly larger hamstring flexibility, which is confirmed by the tests of the popliteal angle. No differences were found in dorsiflexion between girls and boys who have not been trained using a training model.

Physicomechanical, morphological and tribo-deformation characteristics of lightweight WC/AZ31B Mg-matrix biocomposites for hip joint applications.

Exploring high strength materials with a higher concentration of reinforcements in the alloy proves to be a challenging task. This research has explored magnesium-based composites (AZ31B alloy) with tungsten carbide reinforcements, enhancing strength for medical joint replacements via league championship optimisation. The primary objective is to enhance medical joint replacement biomaterials employing magnesium-based composites, emphasising the AZ31B alloy with tungsten carbide reinforcements. The stir casting method is utilised in the manufacture of magnesium matrix composites (MMCs), including varied percentages of tungsten carbide (WC). The mechanical characteristics, such as micro-hardness, tensile strength, and yield strength, have been assessed and compared with computational simulations. The wear studies have been carried out to analyse the tribological behaviour of the composites. Additionally, this study investigates the prediction of stress and the distribution of forces inside bone and joint structures, therefore offering significant contributions to the field of biomedical research. This research contemplates the use of magnesium-based MMCs for the discovery of biomaterials suitable for medical joint replacement. The study focuses on the magnesium alloy AZ31B, with particles ranging in size from 40 to 60 microns used as the matrix material. Moreover, the outcomes have revealed that when combined with MMCs based on AZ31B-magnesium matrix, the WC particle emerges as highly effective reinforcements for the fabrication of lightweight, high-strength biomedical composites. This study uses the league championship optimisation (LCO) approach to identify critical variables impacting the synthesis of Mg MMCs from an AZ31B-based magnesium alloy. The scanning electron microscopy (SEM) images are meticulously analysed to depict the dispersion of WC particulates and the interface among the magnesium (Mg) matrix and WC reinforcement. The SEM analysis has explored the mechanisms underlying particle pull-out, the characteristics of inter-particle zones, and the influence of the AZ31B matrix on the enhancement of the mechanical characteristics of the composites. The application of finite element analysis (FEA) is being used in order to make predictions regarding the distribution of stress and the interactions of forces within the model of the hip joint. This study has compared the physico-mechanical and tribological characteristics of WC to distinct combinations of 0%, 5%, 10% and 15%, and its impact on the performance improvements. SEM analysis has confirmed the findings' improved strength and hardness, particularly when 10%-15% of WC was incorporated. Following the incorporation of 10% of WC particles within Mg-alloy matrix, the outcomes of the study has exhibited enhanced strength and hardness, which furthermore has been evident by utilising SEM analysis. Using ANSYS, structural deformation and stress levels are predicted, along with strength characteristics such as additional hardness of 71 HRC, tensile strength of 140-150 MPa, and yield strength closer to 100-110 MPa. The simulations yield significant insights into the behaviour of the joint under various loading conditions, thus enhancing the study's significance in biomedical environments.

Regional Anesthesia for Hip Arthroscopy.

Pain after hip arthroscopy can be severe, yet we lack a consensus method for non-narcotic analgesia. Here we describe anatomic elements of hip arthroscopy and our current understanding of the relevant sensory innervation as a prelude to the evaluation of locoregional analgesic techniques. Many regional nerve blocks and local anesthetic infiltration techniques are reviewed, including 2 newer ultrasound fascial plane blocks. Further study of targeted, motor-sparing approaches, either ultrasound-guided or under direct surgical visualization is needed.

Posture-induced modulation of lower-limb joint powers in perturbed running.

Despite evidence on trunk flexion's impact on locomotion mechanics, its role in modulating lower-limb energetics during perturbed running remains underexplored. Therefore, we investigated posture-induced power redistribution in the lower-limb joints (hip, knee, and ankle), along with the relative contribution from each joint to total lower-limb average positive and negative mechanical powers (i.e., over time) during perturbed running. Twelve runners (50% female) ran at self-selected (~15°) and three more sagittal trunk inclinations (backward, ~0°; low forward, ~20°; high forward, ~25°) on a custom-built runway, incorporating both a level surface and a 10 cm visible drop-step positioned midway, while simultaneously recording three-dimensional kinematics and kinetics. We used inverse dynamics analysis to determine moments and powers in lower-limb joints. Increasing the trunk forward inclination yielded the following changes in lower-limb mechanics: a) an elevation in total positive power with a distoproximal shift and a reduction in total negative power; b) systematic increases in hip positive power, coupled with decreased and increased contribution to total negative (during level-step) and positive (during drop-step) powers, respectively; c) reductions in both negative and positive knee powers, along with a decrease in its contribution to total positive power. Regardless of the trunk posture, accommodating drop-steps while running demands elevated total limb negative and positive powers with the ankle as a primary source of energy absorption and generation. Leaning the trunk more forward induces a distoproximal shift in positive power, whereas leaning backward exerts an opposing influence on negative power within the lower-limb joints.

Fluoroscopy-guided triple hip block for patients with hip osteoarthritis: A new approach.

Hip osteoarthritis (OA) is found in approximately 10% of the population and often causes disability and social limitations in elderly patients. Intra-articular injections are among the most frequently applied interventional treatments for the hip joint. Femoral and obturator sensorial nerve blocks have also been reported to be effective for both diagnostic and therapeutic purposes. A single needle insertion was performed for the blockage of the hip joint and sensory branches. For the sensory branch of the femoral nerve, the needle is advanced at nearly a 45-degree angle toward below the anterior inferior iliac spine near the anterolateral edge of the hip joint. For the sensory branch of the obturator nerve, the needle is advanced at nearly an angle of 45 degrees toward the area below the junction of the pubis and ischium. Finally, for joint injection, the same needle was advanced toward the midline of the anterior femoral head-neck junction at a steeper angle, and blocks were applied. Three patients with hip osteoarthritis were injected with this method and well-being was achieved in a 3-month follow-up. We think that blockage of the hip joint and peripheral sensory branches with a single needle insertion is a fast and effective method. However, prospective controlled studies are needed to determine the efficacy and safety of the method.

Percutaneous pulsed radiofrequency ablation of articular nerves of the hip joint in patients with chronic hip pain refractory to conventional analgesics.

OBJECTIVES: Total Hip Arthroplasty (THA) may be a risky proposition in patients with comorbidities, and they may require systemic analgesics for chronic hip pain (CHP). Since traditional pain medications may not provide complete pain relief or carry prohibitive adverse effects, pulsed radiofrequency (PRF) treatment of the hip articular nerves (HAN) has been proposed for effective clinical outcomes. We determined the efficacy of PRF-HAN in improvement in CHP compared to baseline pain on conventional systemic analgesics. METHODS: Between August 2015 and December 2021, 31 adult patients with severe comorbid conditions and excruciating chronic hip pain were subjected to a PRF-HAN procedure following a diagnostic block. All 31 patients received PRF of the articular branches of the femoral and obturator nerves. Demographic parameters, numerical rating scale (NRS), Harris Hip Score (HHS), WOMAC scores, the change of these scores from baseline, and any adverse effects were recorded before treatment and on day 1, 1st week, 6 weeks, and 6 months after treatment. RESULTS: All the patients who underwent the PRF-HAN reported a significant improvement in NRS, HHS, and WOMAC scores compared to the baseline values on day 1, at the end of the 1st week, and the 6th week (p<0.001). No adverse events were documented in the study post-procedure until the end of 6 months. CONCLUSION: PRF-HAN is a strong alternative for chronic pain management and augments physical functioning and a return to daily activity in patients who would be deprived of arthroplasty considering associated comorbid conditions.

Experimental assessment of pelvis slipping during postless traction for orthopaedic applications.

BACKGROUND: The application of lower limb traction during hip arthroscopy and femur fractures osteosynthesis is commonplace in orthopaedic surgeries. Traditional methods utilize a perineal post on a traction table, leading to soft tissue damage and nerve neuropraxia. A postless technique, using high-friction pads, has been considered as a potential damage-free alternative. However, whether these pads sufficiently prevent patient displacement remains unknown. Thus, this study systematically assesses the efficacy of commercial high-friction pads (PinkPad and CarePad) in restraining subject displacement, for progressively increasing traction loads and different Trendelenburg angles. METHODS: Three healthy male subjects were recruited and tested in supine and Trendelenburg positions (5° and 10°), using a customized boot-pulley system. Ten load disks (5 kg) were dropped at 15s intervals, increasing gradually the traction load up to 50 kg. Pelvis displacement along the traction direction was measured with a motion capture system. The displacement at 50 kg of traction load was analyzed and compared across various pads and bed inclinations. Response to varying traction loads was statistically assessed with a quadratic function model. RESULTS: Pelvis displacement at 50 kg traction load was below 60 mm for all conditions. Comparing PinkPad and CarePad, no significant differences in displacement were observed. Finally, similar displacements were observed for the supine and Trendelenburg positions. CONCLUSIONS: Both PinkPad and CarePad exhibited nearly linear behavior under increasing traction loads, limiting displacement to 60 mm at most for 50 kg loads. Contrary to expectations, placing subjects in the Trendelenburg position did not increase adhesion.

[Effectiveness analysis of revision surgery after total hip arthroplasty assisted by artificial intelligence preoperative planning system].

Objective: To explore the short-term effectiveness of hip revision surgery guided by artificial intelligence preoperative planning (AIHIP) system. Methods: The clinical data of 22 patients (23 hips) who were admitted between June 2019 and March 2023 and met the selection criteria were retrospectively analyzed. There were 12 males and 10 females with an average age of 69.7 years (range, 44-90 years). There were 19 hips in the first revision, 3 hips in the second revision, and 1 hip in the third revision. The causes of revision included 12 hips with prosthesis loosening, 4 hips with acetabular cup loosening, 3 hips with osteolysis, 2 hips with acetabular dislocation, 1 hip with postoperative infection, and 1 hip with prosthesis wear. There were 6 hips in stage ⅡA, 9 hips in stage ⅡB, 4 hips in stage ⅡC, 3 hips in stage ⅢA, and 1 hip in stage ⅢB according to Paprosky staging of acetabular bone defect. The replacement of prosthesis type, operation time, hospitalization stay, ground active condition, and postoperative infection, fracture, prosthesis loosening, and other adverse events were recorded. The function of the affected limb was evaluated by Harris score before operation, at 1 week and 6 months after operation, and the range of motion of the hip joint was compared before operation and at 6 months after operation. Results: The operation time was 85-510 minutes, with an average of 241.8 minutes; the hospitalization stay was 7-35 days, with an average of 15.2 days; the time of disassociation from the walker was 2-108 days, with an average of 42.2 days. All the 22 patients were followed up 8-53 months (mean, 21.7 months). No adverse events such as prosthesis loosening or infection occurred in the rest of the patients, except for postoperative hematoma of the thigh in 1 patient and dislocation of the hip in 1 hip. The matching degree of acetabular cup was completely matched in 22 hips and mismatched in 1 hip (+2), the matching rate was 95.65%. The matching degree of femoral stem was completely matched in 22 hips and generally matched in 1 hip (-1), and the matching rate was 100%. The Harris scores were 55.3±9.8 and 89.6±7.2 at 1 week and 6 months after operation, respectively, which significantly improved when compared with before operation (33.0±8.6, P<0.05), and further improved at 6 months after operation than at 1 week after operation ( P<0.05). The function of hip joint was evaluated by Harris score at 6 months after operation, and 21 hips were good and 2 hips were moderate, which could meet the needs of daily life. The range of motion of hip joint was (111.09±10.11)° at 6 months after operation, which was significantly different from (79.13±18.50)° before operation ( t=-7.269, P<0.001). Conclusion: AIHIP system can improve the accuracy of revision surgery, reduce the difficulty of surgery, and achieve good postoperative recovery and satisfactory short-term effectiveness.

Wearing a back-support exoskeleton alters lower-limb joint kinetics during single-step recovery following a forward loss of balance.

We assessed the effects of a passive, back-support exoskeleton (BSE) on lower-limb joint kinetics during the initiation and swing phases of recovery from a forward loss of balance. Sixteen (8M, 8F) young, healthy participants were released from static forward-leaning postures and attempted to recover their balance with a single-step while wearing a BSE (backXTM) with different levels of support torque and in a control condition. The BSE provided âˆ¼ 15-20 Nm of external hip extension torque on the stepping leg at the end of initiation and beginning of swing phases. Participants were unable to generate sufficient hip flexion torque, power, and work to counteract this external torque, although they sustained hip flexion torque for a more prolonged period, resulting in slightly increased hip contribution to positive leg work (compared to control). However, net positive leg work, and the net contribution of hip joint (human + BSE) to total leg work decreased with BSE use. While all participants had changes in hip joint kinetics, a significant compensatory increase in ankle contribution to positive leg work was observed only among females. Our results suggest that BSE use adversely affects reactive stepping by decreasing the stepping leg kinetic energy for forward propulsion, and that the relative contributions of lower-limb joints to total mechanical work done during balance recovery are altered by BSE use. BSEs may thus need to be implemented with caution for dynamic tasks in occupational settings, as they may impair balance recovery following a forward loss of balance.

Accuracy of conventional motion capture in measuring hip joint center location and hip rotations during gait, squat, and step-up activities.

Accurate measurements of hip joint kinematics are essential for improving our understanding of the effects of injury, disease, and surgical intervention on long-term hip joint health. This study assessed the accuracy of conventional motion capture (MoCap) for measuring hip joint center (HJC) location and hip joint angles during gait, squat, and step-up activities while using dynamic biplane radiography (DBR) as the reference standard. Twenty-four young adults performed six trials of treadmill walking, six body-weight squats, and six step-ups within a biplane radiography system. Synchronized biplane radiographs were collected at 50 images per second and MoCap was collected simultaneously at 100 images per second. Bone motion during each activity was determined by matching digitally reconstructed radiographs, created from subject-specific CT-based bone models, to the biplane radiographs using a validated registration process. Errors in estimating HJC location and hip angles using MoCap were quantified by the root mean squared error (RMSE) across all frames of available data. The MoCap error in estimating HJC location was larger during step-up (up to 89.3 mm) than during gait (up to 16.6 mm) or squat (up to 31.4 mm) in all three anatomic directions (all p < 0.001). RMSE in hip joint flexion (7.2°) and abduction (4.3°) during gait was less than during squat (23.8° and 8.9°) and step-up (20.1° and 10.6°) (all p < 0.01). Clinical analysis and computational models that rely on skin-mounted markers to estimate hip kinematics should be interpreted with caution, especially during activities that involve deeper hip flexion.

Comparison of quality and interpretation of newborn ultrasound screening examinations for developmental dysplasia of the hip by basically trained nurses and junior physicians with no previous ultrasound experience.

BACKGROUND: We are obliged to give babies the chance to profit from a nationwide screening of developmental dysplasia of the hip in very rural areas of Mongolia, where trained physicians are scarce. This study aimed to compare the quality and interpretation of hip ultrasound screening examinations performed by nurses and junior physicians. METHODS: A group of 6 nurses and 6 junior physician volunteers with no previous ultrasound experience underwent Graf's standard training in hands-on practice. Newborns were examined before discharge from the hospital, according to the national guideline. Two standard documentation images of each hip were saved digitally. The groups were compared on the proportion of good quality of sonograms and correct interpretation. Two Swiss supervisors' agreed diagnosis according to Graf was considered the final reference for the study purposes. RESULTS: A total of 201 newborns (402 hips or 804 sonograms) were examined in the study, with a mean age of 1.3±0.8 days at examination. Junior physicians examined 100 newborns (200 hips or 400 sonograms), while nurses examined 101 newborns (202 hips or 404 sonograms). The study subjects of the two groups were well balanced for the distribution of baseline characteristics. The study observed no statistically significant difference in the quality of Graf's standard plane images between the providers. Eventually, 92.0% (92) of the physician group and 89.1% (90) of the nurse group were correctly diagnosed as "Group A" (Graf's Type 1 hip) or "Non-Group A" hips (p = 0.484). The most common errors among the groups were a missing lower limb, wrong measurement lines, and technical problems. CONCLUSION: Our study provides evidence that while there might be a trend of slightly more technical mistakes in the nurse group, the overall diagnosis accuracy is similar to junior physicians after receiving standard training in Graf's hip ultrasound method. However, after basic training, regular quality control is a must and all participants should receive refresher trainings. More specifically, nurses need training in the identification of anatomical structures.

Sex-based differences in neck selectivity in total hip arthroplasty using a modular femoral neck system.

BACKGROUND: Dislocation is a major complication of total hip arthroplasty (THA). The modular femoral neck system provides practical advantages by allowing adjustment of neck version and length in the presence of intraoperative instability. Anatomical studies have identified morphological differences in the hip joint between men and women. Despite sex-based differences in hip morphology, it remains unclear whether such differences affect neck selectivity in THA using a modular neck system and whether this approach achieves anatomical reconstruction, thereby reducing complications such as dislocation. This study aimed to investigate gender differences in neck selectivity in THA with the modular neck system and assess the clinical impact of the modular neck system. METHODS: A total of 163 THAs using a modular neck system were included in this study. Data on the type of modular neck and intraoperative range of motion (ROM) were retrieved from patient records. Pre- and post-operative leg length differences (LLD) were examined as part of the radiographic assessment. Dislocation was investigated as a postoperative complication. RESULTS: Neck selectivity did not significantly differ between men and women. The comparison of pre- and post-operative LLD revealed a tendency for varus necks to improve LLD more than version-controlled necks. Furthermore, no significant correlation was found between intraoperative ROM and neck selectivity, or postoperative dislocation and neck selectivity. CONCLUSIONS: This study on THA with a modular neck system provided valuable insights into sex-based differences in neck selectivity and highlighted the potential benefits of the modular neck system in addressing LLD and preventing postoperative dislocation.

Validity of muscle activation estimated with predicted ground reaction force in inverse dynamics based musculoskeletal simulation during gait.

The inverse dynamics based musculoskeletal simulation needs ground reaction forces (GRF) as an external force input. GRF can be predicted from kinematic data. However, the validity of estimated muscle activation using the predicted GRF has remained unclear. Therefore, the purpose of this study was to determine the validity of estimated muscle activation with predicted GRF in the inverse dynamics based musculoskeletal simulation. To perform musculoskeletal simulations, an open-source motion capture dataset that contains gait data from 50 healthy subjects was used. CusToM was used for the musculoskeletal simulations. Two sets of inverse dynamics and static optimization were performed, one used predicted GRF (PRED) and another used experimentally measured GRF (EXP). Pearson's correlation was calculated to evaluate the similarity between EMG and estimated muscle activations for both PRED and EXP. To compare PRED and EXP, paired t-tests were used to compare the trial-wise muscle activation similarity and residuals. Relationships between joint moments and residuals were also tested. The overall muscle activation similarity was comparable in PRED (R = 0.477) and EXP (R = 0.475). The residuals were 2-4 times higher in EXP compared to PRED (P < 0.001). The hip flexion-extension moment was correlated to sagittal plane residual moment (R = 0.467). The muscle activations estimated using predicted GRF were comparable to that with measured GRF in the inverse dynamics based musculoskeletal simulation. Prediction of GRF helps to perform musculoskeletal simulations where the force plates are not available.

Effective Stretching Positions of the Piriformis Muscle Evaluated Using Shear Wave Elastography.

CONTEXT: Piriformis syndrome is often associated with muscle spasms and shortening of the piriformis muscle (PM). Physical therapy, including static stretching of the PM, is one of the treatments for this syndrome. However, the effective stretching position of the PM is unclear in vivo. This study aimed to determine the effective stretching positions of the PM using ultrasonic shear wave elastography. DESIGN: Observational study. METHODS: Twenty-one healthy young men (22.7 [2.4] y) participated in this study. The shear elastic modulus of the PM was measured at 12 stretching positions using shear wave elastography. Three of the 12 positions were tested with maximum internal rotation at 0°, 20°, or 40° hip adduction in 90° hip flexion. Nine of the 12 positions were tested with maximum external rotation at positions combined with 3 hip-flexion angles (70°, 90°, and 110°) and 3 hip-adduction angles (0°, 20°, and 40°). RESULTS: The shear elastic modulus of the PM was significantly higher in the order of 40°, 20°, and 0° of adduction and higher in external rotation than in internal rotation. The shear elastic modulus of the PM was significantly greater in combined 110° hip flexion and 40° adduction with maximum external rotation than in all other positions. CONCLUSION: This study revealed that the position in which the PM was most stretched was maximum external rotation with 110° hip flexion and 40° hip adduction.

Neurogenic heterotopic ossification of the hip: Magnetic resonance imaging versus computed tomography for pre-surgical assessment.

PURPOSE: Neurogenic heterotopic ossification (NHO) of the hip is a frequent complication of spinal cord injuries, often requiring surgical management. Pre-surgical imaging assessment is essential, usually with computed tomography (CT)-scan. We aimed to compare magnetic resonance imaging (MRI) and CT for pre-surgical imaging assessment of the NHO, particularly for their relationships with vessels and nerves. METHOD: This prospective study included consecutive patients who underwent surgery for NHO from July 2019 to April 2022. All patients had CT angiography and MRI including Zero Echo Time and TRICKS sequences. Radiologists used standardized reports for CT and MRI to evaluate NHO and their features, bone mineralization, and relation to the arteries, veins and nerves. Agreement between pre-surgical CT and MRI was evaluated. RESULTS: Twenty-four patients (mean age: 53.5 ± 12.2 years) were included, among which 7 had bilateral NHO (31 hips). NHO were anterior in 15/31 hips (48 %), multifragmented in 25/31 hips (81 %). Mild and significant demineralization was most frequent. Gutter and tunnel were reported in 11.1 % of the arteries. Nerves were more often identified in MRI than in CT-scan. Agreement coefficients between CT and MRI were excellent for NHO location (0.95) and implantation (0.92), good for fragmentation (0.70), contact with joint capsule (0.66), bone mineralization (0.74), and relation to arteries (0.85), veins (0.76), sciatic nerve (0.7) and moderate for femoral nerve (0.47). CONCLUSION: MRI exhibited a good agreement with CT for pre-surgical assessment of NHO of the hip, especially to evaluate their relationships with the arteries, veins and sciatic nerve. Femoral nerves were more often identified in MRI than in CT-scan.