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The Journal of International Medical... Mar 2024To compare the biomechanical stability of a novel, C-shaped nickel-titanium shape memory alloy (SMA) implant (C-clip) with traditional cerclage wiring in the fixation of...
BACKGROUND
To compare the biomechanical stability of a novel, C-shaped nickel-titanium shape memory alloy (SMA) implant (C-clip) with traditional cerclage wiring in the fixation of a Vancouver B1 (VB1) periprosthetic femoral fracture (PFF).
METHODS
In total, 18 synthetic femoral fracture models were constructed to obtain unstable VB1 fracture with an oblique fracture line 8 cm below the lesser trochanter. For each model, the distal portion was repaired using a 10-hole locking plate and four distal bi-cortical screws. The proximal portion was repaired using either three, threaded cerclage wirings or three, novel C-shaped implants. Specimens underwent biomechanical testing using axial compression, torsional and four-point bending tests. Each test was performed on three specimens.
RESULTS
The C-clip was statistically significantly stronger (i.e., stiffer) than cerclage wiring in the three biomechanical tests. For axial compression, medians (ranges) were 39 (39-41) and 35 (35-35) N/mm, for the C-clip and cerclage wiring, respectively. For torsion, medians (ranges) were, 0.44 (0.44-0.45) and 0.30 (0.30-0.33) N/mm for the C-clip and cerclage wiring, respectively. For the four-point bending test, medians (ranges) were 39 (39-41) and 28 (28-31) N/mm; for the C-clip and cerclage wiring, respectively.
CONCLUSION
Results from this small study show that the novel, C-shaped SMA appears to be biomechanically superior to traditional cerclage wiring in terms of stiffness, axial compression, torsion and four-point bending, and may be a valuable alternative in the repair of VB1 PFF. Further research is necessary to support these results.
Topics: Humans; Shape Memory Alloys; Femoral Fractures; Femur; Periprosthetic Fractures; Fracture Fixation, Internal; Bone Plates; Biomechanical Phenomena
PubMed: 38534086
DOI: 10.1177/03000605241240946 -
PloS One 2024This study evaluated the biomechanical performance of narrow-diameter implant (NDI) treatment in atrophic maxillary posterior teeth in aging patients by finite element...
This study evaluated the biomechanical performance of narrow-diameter implant (NDI) treatment in atrophic maxillary posterior teeth in aging patients by finite element analysis. The upper left posterior bone segment with first and second premolar teeth missing obtained from a patient's cone beam computed tomography data was simulated with cortical bone thicknesses of 0.5 and 1.0 mm. Three model groups were analyzed. The Regimen group had NDIs of 3.3 × 10 mm in length with non-splinted crowns. Experimental-1 group had NDIs of 3.0 × 10 mm in length with non-splinted crowns and Experimental-2 group had NDIs of 3.0 × 10 mm in length with splinted crowns. The applied load was 56.9 N in three directions: axial (along the implant axis), oblique at 30° (30° to the bucco-palatal plane compared to the vertical axis of the tooth), and lateral load at 90° (90° in the bucco-palatal plane compared to the vertical axis of the tooth). The results of the von Mises stress on the implant fixture, the elastic strain, and principal value of stress on the crestal marginal bone were analyzed. The axial load direction was comparable in the von Mises stress values in all groups, which indicated it was not necessary to use splinted crowns. The elastic strain values in the axial and oblique directions were within the limits of Frost's mechanostat theory. The principal value of stress in all groups were under the threshold of the compressive stress and tensile strength of cortical bone. In the oblique and lateral directions, the splinted crown showed better results for both the von Mises stress, elastic strain, and principal value of stress than the non-splinted crown. In conclusion, category 2 NDIs can be used in the upper premolar region of aging patients in the case of insufficient bone for category 3 NDI restorations.
Topics: Humans; Finite Element Analysis; Bicuspid; Maxilla; Crowns; Splints; Dental Implants; Dental Stress Analysis; Stress, Mechanical; Biomechanical Phenomena
PubMed: 38527030
DOI: 10.1371/journal.pone.0299816 -
Advanced Science (Weinheim,... Jun 2024Articular cartilage and meniscus transfer and distribute mechanical loads in the knee joint. Degeneration of these connective tissues occurs during the progression of...
Articular cartilage and meniscus transfer and distribute mechanical loads in the knee joint. Degeneration of these connective tissues occurs during the progression of knee osteoarthritis, which affects their composition, microstructure, and mechanical properties. A deeper understanding of disease progression can be obtained by studying them simultaneously. Time-resolved synchrotron-based X-ray phase-contrast tomography (SR-PhC-µCT) allows to capture the tissue dynamics. This proof-of-concept study presents a rheometer setup for simultaneous in situ unconfined compression and SR-PhC-µCT of connective knee tissues. The microstructural response of bovine cartilage (n = 16) and meniscus (n = 4) samples under axial continuously increased strain, or two steps of 15% strain (stress-relaxation) is studied. The chondrocyte distribution in cartilage and the collagen fiber orientation in the meniscus are assessed. Variations in chondrocyte density reveal an increase in the top 40% of the sample during loading, compared to the lower half. Meniscus collagen fibers reorient perpendicular to the loading direction during compression and partially redisperse during relaxation. Radiation damage, image repeatability, and image quality assessments show little to no effects on the results. In conclusion, this approach is highly promising for future studies of human knee tissues to understand their microstructure, mechanical response, and progression in degenerative diseases.
Topics: Animals; Cattle; Synchrotrons; Cartilage, Articular; Proof of Concept Study; Knee Joint; Meniscus; Biomechanical Phenomena; Connective Tissue; X-Ray Microtomography; Osteoarthritis, Knee; Stress, Mechanical
PubMed: 38520713
DOI: 10.1002/advs.202308811 -
Orthopaedic Surgery May 2024The biomechanical characteristics of proximal femoral trabeculae are closely related to the occurrence and treatment of proximal femoral fractures. Therefore, it is of...
OBJECTIVE
The biomechanical characteristics of proximal femoral trabeculae are closely related to the occurrence and treatment of proximal femoral fractures. Therefore, it is of great significance to study its biomechanical effects of cancellous bone in the proximal femur. This study examines the biomechanical effects of the cancellous bone in the proximal femur using a controlled variable method, which provide a foundation for further research into the mechanical properties of the proximal femur.
METHODS
Seventeen proximal femoral specimens were selected to scan by quantitative computed tomography (QCT), and the gray values of nine regions were measure to evaluated bone mineral density (BMD) using Mimics software. Then, an intact femur was fixed simulating unilateral standing position. Vertical compression experiments were then performed again after removing cancellous bone in the femoral head, femoral neck, and intertrochanteric region, and data were recorded. According to the controlled variable method, the femoral head, femoral neck, and intertrochanteric trabeculae were sequentially removed based on the axial loading of the intact femur, and the displacement and strain changes of the femur samples under axial loading were recorded. Gom software was used to measure and record displacement and strain maps of the femoral surface.
RESULTS
There was a statistically significant difference in anteroposterior displacement of cancellous bone destruction in the proximal femur (p < 0.001). Proximal femoral bone mass explained 77.5% of the strength variation, in addition proximal femoral strength was mainly affected by bone mass at the level of the upper outer, lower inner, lower greater trochanter, and lesser trochanter of the femoral head. The normal stress conduction of the proximal femur was destroyed after removing cancellous bone, the stress was concentrated in the femoral head and lateral femoral neck, and the femoral head showed a tendency to subside after destroying cancellous bone.
CONCLUSION
The trabecular removal significantly altered the strain distribution and biomechanical strength of the proximal femur, demonstrating an important role in supporting and transforming bending moment under the vertical load. In addition, the strength of the proximal femur mainly depends on the bone density of the femoral head and intertrochanteric region.
Topics: Humans; Biomechanical Phenomena; Cancellous Bone; Bone Density; Tomography, X-Ray Computed; Female; Male; Femur; Aged; Middle Aged; Femur Head; Cadaver
PubMed: 38520122
DOI: 10.1111/os.14044 -
Neuroradiology Jul 2024We investigated whether the quality of high-resolution computed tomography (CT) images of the temporal bone improves with deep learning reconstruction (DLR) compared... (Comparative Study)
Comparative Study
PURPOSE
We investigated whether the quality of high-resolution computed tomography (CT) images of the temporal bone improves with deep learning reconstruction (DLR) compared with hybrid iterative reconstruction (HIR).
METHODS
This retrospective study enrolled 36 patients (15 men, 21 women; age, 53.9 ± 19.5 years) who had undergone high-resolution CT of the temporal bone. Axial and coronal images were reconstructed using DLR, HIR, and filtered back projection (FBP). In qualitative image analyses, two radiologists independently compared the DLR and HIR images with FBP in terms of depiction of structures, image noise, and overall quality, using a 5-point scale (5 = better than FBP, 1 = poorer than FBP) to evaluate image quality. The other two radiologists placed regions of interest on the tympanic cavity and measured the standard deviation of CT attenuation (i.e., quantitative image noise). Scores from the qualitative and quantitative analyses of the DLR and HIR images were compared using, respectively, the Wilcoxon signed-rank test and the paired t-test.
RESULTS
Qualitative and quantitative image noise was significantly reduced in DLR images compared with HIR images (all comparisons, p ≤ 0.016). Depiction of the otic capsule, auditory ossicles, and tympanic membrane was significantly improved in DLR images compared with HIR images (both readers, p ≤ 0.003). Overall image quality was significantly superior in DLR images compared with HIR images (both readers, p < 0.001).
CONCLUSION
Compared with HIR, DLR provided significantly better-quality high-resolution CT images of the temporal bone.
Topics: Humans; Female; Male; Deep Learning; Temporal Bone; Middle Aged; Retrospective Studies; Tomography, X-Ray Computed; Radiographic Image Interpretation, Computer-Assisted; Adult; Aged
PubMed: 38514472
DOI: 10.1007/s00234-024-03330-1 -
Foot (Edinburgh, Scotland) Jun 2024Talar neck fractures are rare but potentially devastating injuries, with early reduction and rigid fixation essential to facilitate union and prevent avascular necrosis.... (Comparative Study)
Comparative Study
BACKGROUND
Talar neck fractures are rare but potentially devastating injuries, with early reduction and rigid fixation essential to facilitate union and prevent avascular necrosis. Even small degrees of malunion will alter load transmission and subtalar joint kinematics. Changes in fixation techniques have led to dual plating strategies. While locked plating has perceived advantages in porotic bone and comminution, its biomechanical benefits in talar neck fractures have not been shown.
AIM
To compare the strength of locking vs. non-locking plate fixation in comminuted talar neck fractures.
METHOD
Seven pairs of cadaveric tali were randomised to locking or non-locking plate fixation. A standardised model of talar neck fracture with medial comminution was created, and fixation performed. The fixed specimens were mounted onto a motorised testing device, and an axial load applied.
RESULTS
Peak load to failure, deformation at failure, work done to achieve failure, and stiffness of the constructs were measured. No statistically significant difference was found between locking and non-locking constructs for all parameters.
CONCLUSIONS
Both constructs provide similar strength to failure in talar neck fracture fixations. Mean peak load to failure did not exceed the theoretical maximum forces generated of 1.1 kN when weight-bearing. We would advocate caution with early mobilisation in both fixations.
Topics: Humans; Bone Plates; Talus; Fracture Fixation, Internal; Cadaver; Fractures, Comminuted; Biomechanical Phenomena; Male; Female; Middle Aged; Aged; Weight-Bearing; Fractures, Bone
PubMed: 38513373
DOI: 10.1016/j.foot.2024.102084 -
Pain Physician Mar 2024Vertebral compression fractures (VCFs) can affect the entire spinopelvic complex and cause unpredictable patterns of back pain due to their effects on spinal tensegrity...
BACKGROUND
Vertebral compression fractures (VCFs) can affect the entire spinopelvic complex and cause unpredictable patterns of back pain due to their effects on spinal tensegrity and biomechanical compensation. They can lead to significant morbidity and mortality in the aging population and are difficult to diagnose. We aimed to establish a relationship between VCFs and sacroiliac (SI) joint pain.
OBJECTIVES
Demonstration of SI joint (SIJ) pain relief at up to 6 months after kyphoplasty (KP) in patients with VCFs and diagnosed SI dysfunction.
STUDY DESIGN
Retrospective study.
SETTING
All patients were from a private chronic pain and orthopedics practice in the northeastern United States.
METHODS
Fifty-one patients with VCFs diagnosed through imaging and SIJ dysfunction diagnosed through 2 diagnostic SIJ blocks who had failed conservative management were considered for KP. Numeric Rating Scale (NRS 11) scores were recorded at the baseline, after each SIJ block, and at 4 weeks and then 6 months after KP.
RESULTS
Forty-nine patients underwent KP. At 4 weeks after the procedure, there was an 84% average reduction in NRS scores from the baseline (P < 0.01). At 6 months after the procedure, there was an 80% reduction in NRS scores from the baseline (P < 0.01).
LIMITATIONS
Larger sample sizes and a randomized control trial would be important steps in furthering the relationship between VCFs and SIJ.
CONCLUSION
VCFs can cause a referred pain pattern to the SIJ that is best treated by KP for long-term management.
Topics: Aged; Humans; Arthralgia; Fractures, Compression; Pelvic Pain; Retrospective Studies; Sacroiliac Joint; Spinal Fractures
PubMed: 38506686
DOI: No ID Found -
BMC Musculoskeletal Disorders Mar 2024To investigate the biochemical changes in lumbar facet joint (LFJ) and intervertebral disc (IVD) with different degenerative grade by T2* mapping.
BACKGROUND
To investigate the biochemical changes in lumbar facet joint (LFJ) and intervertebral disc (IVD) with different degenerative grade by T2* mapping.
METHODS
Sixty-eight patients with low back pain (study group) and 20 volunteers (control group) underwent standard MRI protocols and axial T2* mapping. Morphological evaluation of LFJ and IVD were performed on T2-weighted imaging according to Weishaupt and Pfirrmann grading system, respectively. T2* values of LFJ and of AF (anterior annulus fibrosus), NP (nucleus pulposus), and PF (posterior annulus fibrosus) in IVD were measured. Kruskal-Wallis test and Wilcoxon rank-sum test were used to compare T2* values of subjects with different degenerative grade.
RESULTS
The mean T2* value of grade 0 LFJ (21.68[17.77,26.13]) was higher than those of grade I (18.42[15.68,21.8], p < 0.001), grade II (18.98[15.56,22.76], p = 0.011) and grade III (18.38[16.05,25.07], p = 0.575) LFJ in study group, and a moderate correlation was observed between T2* value and LFJ grade (rho=-0.304, p < 0.001) in control group. In the analysis of IVD, a moderate correlation was observed between AF T2* value and IVD grade (rho=-0.323, p < 0.001), and between NP T2* value and IVD grade (rho=-0.328, p < 0.001), while no significant difference was observed between the T2* values of PF in IVD of different grade in study group.
CONCLUSIONS
Downward trend of T2* values can be found in LFJ, AF and NP as the degenerative grade rised. But in elderly patients with low back pain, no change trend was found in LFJ due to increased fluid accumulation in the joint space.
Topics: Humans; Aged; Intervertebral Disc Degeneration; Zygapophyseal Joint; Low Back Pain; Lumbar Vertebrae; Intervertebral Disc; Magnetic Resonance Imaging
PubMed: 38504210
DOI: 10.1186/s12891-024-07265-9 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Mar 2024To evaluate the correlation between pelvic incidence (PI) angle, hip deflection angle (HDA), combined deflection angle (CDA) and osteonecrosis of the femoral head (ONFH)...
OBJECTIVE
To evaluate the correlation between pelvic incidence (PI) angle, hip deflection angle (HDA), combined deflection angle (CDA) and osteonecrosis of the femoral head (ONFH) after femoral neck fracture, in order to explore early predictive indicators for ONFH occurrence after femoral neck fracture.
METHODS
A study was conducted on patients with femoral neck fractures who underwent cannulated screw internal fixation between December 2018 and December 2020. Among them, 208 patients met the selection criteria and were included in the study. According to the occurrence of ONFH, the patients were allocated into ONFH group and non-NOFH group. PI, HDA, and CDA were measured based on the anteroposterior X-ray films of pelvis and axial X-ray films of the affected hip joint before operation, and the differences between the two groups were compared. The receiver operating characteristic curve (ROC) was used to evaluate the value of the above imaging indicators in predicting the occurrence of ONFH.
RESULTS
Among the 208 patients included in the study, 84 patients experienced ONFH during follow-up (ONFH group) and 124 patients did not experience ONFH (non-ONFH group). In the non-ONFH group, there were 59 males and 65 females, the age was 18-86 years (mean, 53.9 years), and the follow-up time was 18-50 months (mean, 33.2 months). In the ONFH group, there were 37 males and 47 females, the age was 18-76 years (mean, 51.6 years), and the follow-up time was 8-45 months (mean, 22.1 months). The PI, HDA, and CDA were significantly larger in the ONFH group than in the non-ONFH group ( <0.05). ROC curve analysis showed that the critical value of PI was 19.82° (sensitivity of 40.5%, specificity of 86.3%, <0.05); the critical value of HDA was 20.94° (sensitivity of 77.4%, specificity of 75.8%, <0.05); and the critical value of CDA was 39.16° (sensitivity of 89.3%, specificity of 83.1%, <0.05).
CONCLUSION
There is a correlation between PI, HDA, CDA and the occurrence of ONFH after femoral neck fracture, in which CDA can be used as an important reference indicator. Patients with CDA≥39.16° have a higher risk of ONFH after femoral neck fracture.
Topics: Male; Female; Humans; Adolescent; Young Adult; Adult; Middle Aged; Aged; Aged, 80 and over; Femur Head; Femoral Neck Fractures; Femur Head Necrosis; Hip Joint; Fracture Fixation, Internal; Retrospective Studies
PubMed: 38500422
DOI: 10.7507/1002-1892.202311094