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The Journal of Arthroplasty Jun 2024Research on hip instability has focused on establishing "safe" ranges of combined component position in supine posture or functional placement of the acetabular...
Decreased "Polar Axis Angle" is Associated with Instability after Total Hip Arthroplasty: A New Method to Assess Functional Component Position on Lateral Seated Radiographs.
BACKGROUND
Research on hip instability has focused on establishing "safe" ranges of combined component position in supine posture or functional placement of the acetabular component based on the hip-spine relationship. A new angle, the polar axis angle (PAA), of the total hip arthroplasty (THA) components describes the concentricity of both components and can be evaluated in functional positions that confer a greater risk of instability (i.e., sitting). The goal of this study was to compare the polar axis angle in functional positions between patients who experienced a postoperative dislocation, and a matched control group who did not have a dislocation.
METHODS
An institutional database was searched for patients experiencing a dislocation after primary THA. Patients who had postoperative full-length standing and seated lateral radiographs were included in the dislocator group. A control group of non-dislocator patients was matched 2:1 by age, body mass index (BMI), sex, and hip-spine classification. Radiographic measurements of the neck angle, acetabular ante-inclination, and polar axis angle (PAA) were performed by two separate blinded, trained reviewers.
RESULTS
The lateral seated neck angle and lateral seated polar axis angle measurements were significantly lower in the dislocator groups (n = 37) when compared with the control group (n = 74) (23 versus 33 degrees, P < 0.001; 74 versus 83 degrees, P = 0.012, respectively). Significant differences were also observed in changes in the polar axes and neck angles between standing and seated positions (P < 0.001 and P < 0.001, respectively). When comparing patients who have mobile spines versus stiff spines within the dislocator group, there were no differences in the acetabular, neck, or polar axis angles. The effect of neck angle on the polar axis angle showed a linear trend across cohorts.
CONCLUSIONS
Patients who experience postoperative instability have a significantly lower polar axis angle on lateral seated radiographs when matched for age, sex, BMI, and hip-spine classification. In addition, the lower seated polar axis angle is driven more strongly by decreased functional femoral anteversion, which emphasizes the role of functional femoral version on stability in THA.
PubMed: 38909855
DOI: 10.1016/j.arth.2024.06.039 -
The Journal of Biological Chemistry Jun 2024Nonribosomal peptide synthetases (NRPSs) are responsible for the production of important biologically active peptides. The large, multidomain NRPSs operate through an...
Nonribosomal peptide synthetases (NRPSs) are responsible for the production of important biologically active peptides. The large, multidomain NRPSs operate through an assembly line strategy in which the growing peptide is tethered to carrier domains that deliver the intermediates to neighboring catalytic domains. While most NRPS domains catalyze standard chemistry of amino acid activation, peptide bond formation and product release, some canonical NRPS catalytic domains promote unexpected chemistry. The paradigm monobactam antibiotic sulfazecin is produced through the activity of a terminal thioesterase domain of SulM, which catalyzes an unusual β-lactam forming reaction in which the nitrogen of the C-terminal N-sulfo-2,3-diaminopropionate residue attacks its thioester tether to release the monobactam product. We have determined the structure of the thioesterase domain as both a free-standing domain and a didomain complex with the upstream holo peptidyl-carrier domain. The position of variant lid helices results in an active site pocket that is quite constrained, a feature that is likely necessary to orient the substrate properly for β-lactam formation. Modeling of a sulfazecin tripeptide into the active site identifies a plausible binding mode identifying potential interactions for the sulfamate and the peptide backbone with Arg2849 and Asn2819, respectively. The overall structure is similar to the β-lactone forming thioesterase domain that is responsible for similar ring closure in the production of obafluorin. We further use these insights to enable bioinformatic analysis to identify additional, uncharacterized β-lactam-forming biosynthetic gene clusters by genome mining.
PubMed: 38908753
DOI: 10.1016/j.jbc.2024.107489 -
Medical Engineering & Physics Jul 2024The aim of this work is to investigate in-silico the biomechanical effects of a proximal fibular osteotomy (PFO) on a knee joint with different varus/valgus deformities...
The aim of this work is to investigate in-silico the biomechanical effects of a proximal fibular osteotomy (PFO) on a knee joint with different varus/valgus deformities on the progression of knee osteoarthritis (KOA). A finite element analysis (FEA) of a human lower extremity consisting of the femoral, tibial and fibular bones and the cartilage connecting them was designed. The FEA was performed in a static standing primitive position to determine the contact pressure (CP) distribution and the location of the center of pressure (CoP). The analysis examined the relationship between these factors and the degree of deformation of the hip-knee angle in the baseline condition. The results suggested that PFO could be a simple and effective surgical treatment for patients with associated genu varum. This work also reported that a possible CP homogenization and a CoP correction can be achieved for medial varus deformities after PFO. However, it reduced its effectiveness for tibial origin valgus misalignment and worsened in cases of femoral valgus misalignment.
Topics: Osteotomy; Humans; Biomechanical Phenomena; Knee Joint; Pressure; Finite Element Analysis; Computer Simulation; Fibula
PubMed: 38906579
DOI: 10.1016/j.medengphy.2024.104185 -
Medical Engineering & Physics Jul 2024Numerous studies have suggested that the primary cause of failure in transtibial anterior cruciate ligament reconstruction (ACLR) is often attributed to non-anatomical...
Numerous studies have suggested that the primary cause of failure in transtibial anterior cruciate ligament reconstruction (ACLR) is often attributed to non-anatomical placement of the bone tunnels, typically resulting from improper tibial guidance. We aimed to establish the optimal tibial tunnel angle for anatomical ACLR by adapting the transtibial (TT) technique. Additionally, we aimed to assess graft bending angle (GBA) and length changes during in vivo dynamic flexion of the knee. Twenty knee joints underwent a CT scan and dual fluoroscopic imaging system (DFIS) to reproduce relative knee position during dynamic flexion. For the single-legged lunge, subjects began in a natural standing position and flexed the right knee beyond 90° When performing the lunge task, the subject supported the body weight on the right leg, while the left leg was used to keep the balance. The tibial and femoral tunnels were established on each knee using a modified TT technique for single-bundle ACLR. The tibial tunnel angulation to the tibial axis and the sagittal plane were measured. Considering that ACL injuries tend to occur at low knee flexion angles, GBA and graft length were measured between 0° and 90° of flexion in this study. The tibial tunnel angulated the sagittal plane at 42.8° ± 3.4°, and angulated the tibial axis at 45.3° ± 5.1° The GBA was 0° at 90° flexion of the knee and increased substantially to 76.4 ± 5.5° at 0° flexion. The GBA significantly increased with the knee extending from 90° to 0° (p < 0.001). The ACL length was 30.2mm±3.0 mm at 0° flexion and decreased to 27.5mm ± 2.8 mm at 90° flexion (p = 0.072). To achieve anatomic single-bundle ACLR, the optimal tibial tunnel should be angulated at approximately 43° to the sagittal plane and approximately 45° to the tibial axis using the modified TT technique. What's more, anatomical TT ACLR resulted in comparable GBA and a relatively constant ACL length from 0° to 90° of flexion. These findings provide theoretical support for the clinical application and the promotion of the current modified TT technique with the assistance of a robot to achieve anatomical ACLR.
Topics: Humans; Anterior Cruciate Ligament Reconstruction; Tibia; Male; Adult; Young Adult; Female; Anterior Cruciate Ligament
PubMed: 38906575
DOI: 10.1016/j.medengphy.2024.104190 -
European Journal of Vascular and... Jun 2024Iliofemoral venous obstructive disease can result in significant, potentially debilitating symptoms that can negatively affect quality of life. Unlike arterial disease,...
OBJECTIVE
Iliofemoral venous obstructive disease can result in significant, potentially debilitating symptoms that can negatively affect quality of life. Unlike arterial disease, patients with deep venous disease have a significantly lower median age, therefore the need for long term stent patency becomes a matter of decades rather than years. Furthermore, iliofemoral lesions frequently require stent placement across the inguinal ligament. Such stents are subject to dynamic stress from leg movement and associated concerns for device fatigue, resulting in stent fracture. The aim of this study was to describe an in vitro 50 year stent fatigue test method designed to assess durability against dynamic stress induced device fracture.
METHODS
Through literature review, cadaver studies, and computer modelling, the most challenging loading was confirmed to be hip flexion across the inguinal ligament. This occurs when the patient adjusts between a seated and standing position. Sit to stand hip flexion at the inguinal ligament was effectively simulated on the bench in this in vitro experimental study.
RESULTS
When tested under challenge parameters, hip flexion was reliably found to cause fractures in non-venous nitinol stents. However, a dedicated self expanding nitinol venous stent, engineered for improved durability, underwent up to 50 years of simulated loading on the bench with 15% (3/20) of stents experiencing fractures at 50 years, compared with fractures in 35% (14/40) of non-venous stents tested to 1.4 years; no statistical testing was performed as durations do not match and the objective was to demonstrate the test method).
CONCLUSION
The presented fatigue test method is a suitable approach for evaluating the durability of stents intended for venous use. Venous stents demonstrated superior fatigue resistance compared with non-venous stents via in vitro hip flexion testing.
PubMed: 38906369
DOI: 10.1016/j.ejvs.2024.06.024 -
Gait & Posture Jun 2024Intrinsic foot muscles are known to support the medial longitudinal arch (MLA) and stabilize the foot, and they are activated with weight bearing and increased postural...
BACKGROUND
Intrinsic foot muscles are known to support the medial longitudinal arch (MLA) and stabilize the foot, and they are activated with weight bearing and increased postural demand. Various types of intrinsic foot muscle training have been reported, but one of the most useful of these, the short foot exercise, is challenging to perform effectively and requires practice, making it difficult to implement in ordinary clinical settings.
RESEARCH QUESTION
What are the differences in abductor hallucis longus (ABH) muscle activity and MLA angle during intrinsic foot muscle exercises that employ weight bearing and balancing conditions when they are performed with minimal practice?
METHODS
Sixteen healthy volunteers performed nine different intrinsic foot muscle exercises, practiced once or twice. The exercises consisted of toe curl, short foot without pushing, short foot with pushing and toe spread exercises in sitting and standing positions, and single leg swing in a standing position. Each exercise was performed three times for five seconds. The activities of the ABH muscles were measured using surface electromyographic (EMG) sensors and the MLA angles during the exercises were captured using an optical motion tracking system. The integrals of the ABH EMG signals were calculated.
RESULTS
Differences in the integral and maximum of the ABH EMG signal were found between the exercises (p < 0.001). Post-hoc pair-wise analysis revealed that the EMG activity was larger during the swing exercise than in exercises other than toe spread, both in sitting and standing positions, and short foot exercise with pushing while standing. The minimum MLA angle during each exercise was smaller for the toe spread exercise in a sitting position than other exercises (p < 0.023).
SIGNIFICANCE
A single leg swing exercise may be effective for self-exercise of intrinsic foot muscles, particularly when intensive supervised physiotherapy is not possible.
PubMed: 38905851
DOI: 10.1016/j.gaitpost.2024.06.008 -
International Journal of Occupational... Jun 2024Both physical and psychosocial risk factors contributing to musculoskeletal disorders occur in the professional nursing group, and previous literature suggested that...
OBJECTIVES
Both physical and psychosocial risk factors contributing to musculoskeletal disorders occur in the professional nursing group, and previous literature suggested that their interaction may increase the risk of musculoskeletal pain among nurses. The aim of the study was to examine perceived workload and stress as well as physical findings and musculoskeletal complaints in nurses.
MATERIAL AND METHODS
The participants consisted of 42 female nurses, age range 23-60 years. They marked on a pain drawing the site/sites that was/were painful at the moment of testing, its duration and intensity. Thereafter they were examined using the movement and respiration domains from the Global Physiotherapy Examination (GPE). Furthermore, a subjective workload measure was made using the paper version of the and stress was assessed using the .
RESULTS
Almost the entire study group declared that pain experienced in at least 1 location was chronic, i.e., had lasted ≥1 year (97%). The most frequent locations of pain were low back (22.4%) and cervical/head (21.6%) regions. In the GPE, most scores indicated restricted and reduced movement, with the subdomain flexibility having the highest deviation from the predefined standard. Furthermore, the results indicated hampered respiration, especially visible in standing position. Out of all workload scores, the highest was obtained for temporal demand. Perceived stress level was found to be moderate and significantly associated to chronic chest/ thoracic pain. Interestingly, the compression of thorax test positively correlated with mental (r = 0.42, p < 0.05) and physical demand (r = 0.35, p < 0.05), whereas the elbow drop test and temporal demand correlated negatively (r = -0.37, p < 0.05).
CONCLUSIONS
To sum up, the majority of nurses participating in this study had long-lasting pain and limited flexibility of the body and hampered respiration, which both may enhance intensity of experienced musculoskeletal pain. Int J Occup Med Environ Health. 2024;37(3).
PubMed: 38904294
DOI: 10.13075/ijomeh.1896.02389 -
Porto Biomedical Journal 2024We developed two methods for three-dimensional (3D) evaluation of spinal alignment in standing position by image matching between biplanar x-ray images and 3D vertebral...
We developed two methods for three-dimensional (3D) evaluation of spinal alignment in standing position by image matching between biplanar x-ray images and 3D vertebral models. One used a Slot-Scanning 3D x-ray Imager (sterEOS) to obtain biplanar x-ray images, and the other used a conventional x-ray system and a rotating table. The 3D vertebral model was constructed from the CT scan data. The spatial position of the vertebral model was determined by minimizing the contour difference between the projected image of the model and the biplanar x-ray images. Verification experiments were conducted using a torso phantom. The relative positions of the upper vertebrae to the lowest vertebrae of the cervical, thoracic, and lumbar vertebrae were evaluated. The mean, standard deviation, and mean square error of the relative position were less than 1° and 1 mm in all cases for sterEOS. The maximum mean squared errors of the conventional x-ray system and the rotating table were 0.7° and 0.4 mm for the cervical spine, 1.0° and 1.2 mm for the thoracic spine, and 1.1° and 1.2 mm for the lumbar spine. Therefore, both methods could be useful for evaluating the spinal alignment in standing position.
PubMed: 38903393
DOI: 10.1097/j.pbj.0000000000000256 -
Acta Medica Okayama Jun 2024There have been few investigations into the effectiveness of thoracic spine exercises for improving thoracic range of motion (ROM) in any plane. This study assessed the... (Comparative Study)
Comparative Study
There have been few investigations into the effectiveness of thoracic spine exercises for improving thoracic range of motion (ROM) in any plane. This study assessed the effectiveness of two thoracic spine exercises: one in the quadruped position and one in the thoracic standing position. We determined how these exercises affect thoracic spine mobility ROM over a 2-week intervention period. Thirty-nine healthy participants were enrolled and assigned to a Quadruped Thoracic Rotation group (n=17 participants: 9 females and 8 males) or Flamenco Thoracic Spine Rotation group (n=22: 14 females and 8 males). All participants were administered a KOJI AWARENESSTM screening test, and the initial thoracic spine ROM before intervention exercise was measured in a laboratory setting. Quadruped Thoracic Rotation was performed as the quadruped exercise and Flamenco Thoracic Spine Rotation as the standing exercise. The KOJI AWARENESSTM thoracic spine test and ROM were evaluated on the day after the first exercise session and again after the program. Despite their different approaches to thoracic mobility, the quadruped exercise and standing exercise achieved equivalent improvement in thoracic ROM after 2 weeks. Practitioners have a range of exercise options for enhancing thoracic mobility based on their environmental or task-specific needs.
Topics: Humans; Male; Female; Range of Motion, Articular; Adult; Thoracic Vertebrae; Rotation; Young Adult; Exercise Therapy
PubMed: 38902213
DOI: 10.18926/AMO/67200 -
Journal of Clinical Medicine Jun 2024Degenerative joint disease is a dynamic pathological process characterised by a destabilisation of the degradation and synthesis processes of articular cartilage and...
Degenerative joint disease is a dynamic pathological process characterised by a destabilisation of the degradation and synthesis processes of articular cartilage and subchondral bone layer. Studies suggest that individuals with gonarthrosis experience deficits in proprioception, in addition to changes within their joints, which directly affects their ability to maintain posture and increases their risk of falling. The aim of this study was to assess the functional status of patients with gonarthrosis through a posturographic examination conducted on a stabilometric platform (force plate) and a functional clinical examination. Participants were divided into two groups-a control group ( = 125) and a study group ( = 125). During the qualification process, subjective and objective examinations were conducted, including a functional assessment by means of such tests as the "Up and Go" Test, Functional Reach Test, Five Time Sit to Stand Test, and the Step Test. Subsequently, an assessment was conducted on the force plate by means of a posturographic test-the Romberg test performed with open and closed eyes in a standing position-and balance was evaluated using the Berg Balance Scale. The obtained data were analysed with the use of the IBM SPSS Statistics software version 27.0, by means of the Mann-Whitney test, and correlations were determined by means of Spearman's test. A significance level of = 0.05 was adopted. Statistically significant differences were observed among the assessed groups as a result of both functional and posturographic examinations, along with positive correlations for disease duration, age, and BMI index. Patients with gonarthrosis exhibited disturbances in balance, functionality, and posture compared to healthy individuals in the control group.
PubMed: 38893009
DOI: 10.3390/jcm13113298