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Knee Surgery, Sports Traumatology,... Sep 2022Kinematic alignment (KA) aligns the femoral implant perpendicular to the cylindrical axis in the frontal and axial plane. Identification of the kinematic axes when using...
PURPOSE
Kinematic alignment (KA) aligns the femoral implant perpendicular to the cylindrical axis in the frontal and axial plane. Identification of the kinematic axes when using the mini-invasive sub-quadricipital approach is challenging in unicompartmental knee arthroplasty (UKA). This study aims to assess if the orientation of condylar walls may be suitable for use as an anatomical landmark to kinematically align the femoral component in medial UKA. It was hypothesised that the medial wall of the medial condyle would prove to be a reliable anatomical landmark to set both the frontal and axial alignment of the femoral component in medial UKA.
METHODS
73 patients undergoing medial UKA had pre-operative CT imaging to generate 3D models. Those with osteophytes that impaired visualisation of the condylar walls were excluded. 28 patients were included in the study. The ideal KA was determined using the cylindrical axis in the frontal and axial plane. Simulations using the medial wall of the medial condyle (MWMC) and the lateral wall of the medial condyle (LWMC) were performed to set the frontal alignment. To set the axial alignment, the MWMC, LWMC, medial wall of the lateral condyle (MWLC), and medial diagonal line (MDL) anatomical landmarks were investigated. Differences between the ideal measured KA values and values obtained using landmarks were investigated.
RESULTS
Use of the MWMC let to similar frontal alignment compared to the ideal KA (2.9° valgus vs 3.4° valgus, p = 0.371) with 46.4% (13/28) of measurements being [Formula: see text] 1.0° different from the ideal KA and only 1 simulation with greater than 4.0° difference. Use of the MWMC led to very similar axial alignments compared to the ideal KA (0.5° internal vs 0.0°, p = 0.960) with 75.0% (21/28) of measurements being [Formula: see text] 1.0 different from the ideal KA, and a maximum difference of 3.0°. Use of the MWLC and MDL was associated with significant statistical differences when compared to the ideal KA (p < 0.001 for both).
CONCLUSIONS
The native orientation of the medial condylar wall seems to be a reliable anatomical landmark for aligning the femoral component in medial KA UKA in both the axial plane and frontal planes. Other assessed landmarks were shown to not be reliable. Clinical and radiographic assessments of the reliability of using the MWMC to set the frontal and axial orientation of the femoral component when performing a medial KA UKA are needed.
Topics: Arthroplasty, Replacement, Knee; Biomechanical Phenomena; Femur; Humans; Knee Joint; Knee Prosthesis; Reproducibility of Results
PubMed: 34363490
DOI: 10.1007/s00167-021-06683-9 -
Journal of the Mechanical Behavior of... Mar 2023In this study, we propose a 3D non-linear finite element (FE) unit-cell model to investigate the post-yield behavior of mineralized collagen fibril arrays (FAY). We then...
In this study, we propose a 3D non-linear finite element (FE) unit-cell model to investigate the post-yield behavior of mineralized collagen fibril arrays (FAY). We then compare the predictions of the model with recent micro-tensile and micropillar compression tests in both axial and transverse directions. The unit cell consists of mineralized collagen fibrils (MCFs) embedded in an extrafibrillar matrix (EFM), and the FE mesh is equipped with cohesive interactions and a custom plasticity model. The simulation results confirm that MCF plays a dominant role in load bearing prior to yielding under axial tensile loading. Damage was initiated via debonding in shear and progressive sliding at the MCF/EFM interface, and resulted in MCF pull-out until brittle failure. In transverse tensile loading, EFM carried most of the load in pre-yield deformation, and then mixed normal/shear debonding between MCF and EFM began to form, which eventually produced brittle delamination of the two phases. The loading/unloading FE analysis in compression along both axial and transverse directions demonstrated perfect plasticity without any reduction in elastic modulus, i.e., damage due to the interfaces as seen in micropillar compression. Beyond the brittle and ductile nature of the stress-strain curves, in tensile and compressive loading, the simulated post-yield behavior and failure mechanism are in good quantitative agreement with the experimental observations. Our rather simple but efficient unit-cell FE model can reproduce qualitatively and quantitatively the mechanical behavior of bone ECM under tensile and compressive loading along the two main orientations. The model's integration into higher length scales may be useful in describing the macroscopic post-yield and failure behavior of trabecular and cortical bone in greater detail.
Topics: Collagen; Finite Element Analysis; Stress, Mechanical; Bone and Bones; Cortical Bone
PubMed: 36638635
DOI: 10.1016/j.jmbbm.2023.105660 -
Journal of Orthopaedic Research :... Aug 2021Lumbar developmental spinal stenosis (DSS) refers to multilevel pre-existing narrowed spinal canals, which predispose to neural compromise. The objective of this study...
Lumbar developmental spinal stenosis (DSS) refers to multilevel pre-existing narrowed spinal canals, which predispose to neural compromise. The objective of this study is to identify any inheritance pattern of DSS by utilizing pedigree charts. This was a case series of 13 families with a total of 80 subjects having magnetic resonance imaging (MRI) from L1 to S1. Cases (subjects with DSS) or controls (subjects without DSS) were identified by measuring their anteroposterior (AP) vertebral canal diameters. Multilevel model analyses were also performed to evaluate whether there is substantial clustering of observations within the families, and the effect of multilevel DSS. The intraclass correlation coefficient (ICC) and Akaike information criteria (AIC) were compared between models. Correlations between subject demographics and AP vertebral canal diameter were statistically insignificant at all levels. Only vertebral canal cross-sectional area, and axial and sagittal vertebral canal diameter were found to be statistically different between cases and controls at all levels (all p < .05). Both males and females were affected by DSS and there was no skipping of generation, which highly suggested DSS followed an autosomal dominant inheritance pattern. After accounting for multilevel DSS, there was a drop of more than 10 in AIC and some variances were also explained within families. This is the first study that suggests multilevel lumbar DSS to have an autosomal dominant inheritance pattern. Within families with a background of DSS, subjects had a smaller canal size, contributed by shortened axial and sagittal AP vertebral canal diameter, and smaller canal cross-sectional area.
Topics: Female; Humans; Inheritance Patterns; Lumbar Vertebrae; Male; Pedigree; Spinal Canal; Spinal Stenosis
PubMed: 32902878
DOI: 10.1002/jor.24850 -
Orthopaedic Surgery Jan 2023The adjusted mechanical alignment (aMA) technique is an extension of conventional mechanical alignment (MA), which has rarely been reported. The purpose of this study...
OBJECTIVE
The adjusted mechanical alignment (aMA) technique is an extension of conventional mechanical alignment (MA), which has rarely been reported. The purpose of this study was to evaluate mid-term outcomes of navigation-assisted total knee arthroplasty (TKA) using aMA.
METHODS
This retrospective cohort study enrolled 63 consecutive patients (77 knees) who underwent navigation-assisted TKA using aMA between September 2017 and October 2019. Fifty-two consecutive patients (61 knees) who underwent TKA using MA during the same period were assessed as the controlled group. The demographic data and perioperative data were recorded. The parameters of resection and soft tissue balance including tibia resection angle, frontal femoral angle, axial femoral angle, joint line translation, medial and lateral gap in extension and flexion position were recorded. Radiographic parameters and functional scores including the Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and Forgotten Joint Score-12 (FJS-12) were evaluated. Surgery-related complications were recorded. The average follow-up was 3.5 years, with a minimum of 2.4 years.
RESULTS
The frontal femoral angle was 2.55° ± 1.08° in aMA group versus 0.26° ± 0.60° in MA group (p < 0.001). The axial femoral angle was 3.07° ± 2.23° external in aMA group versus 2.30° ± 1.70° in MA group (p = 0.027). The lateral flexion gap was wider in the aMA group, with a mean of 0.71 mm more laxity (p = 0.001). Postoperative coronal alignment was 177.03° ± 1.82° in aMA group versus 178.14° ± 1.69° in MA group (p < 0.001). The coronal femoral component angle was 92.62° ± 2.78° in aMA group versus 90.85° ± 2.01° in MA group (p < 0.001). Both aMA-TKA and MA-TKA achieved satisfactory mid-term clinical outcomes. However, the HSS scores at 1 month postoperatively were significantly higher using aMA than using MA (p < 0.001).
CONCLUSION
Navigation-assisted TKA using aMA technique obtained satisfactory mid-term clinical outcomes. The aMA technique aims to produce a biomimetic wider lateral flexion-extension gap and minimize releases of soft tissues, which might be associated with better early clinical outcomes than MA technique.
Topics: Humans; Arthroplasty, Replacement, Knee; Knee Joint; Retrospective Studies; Femur; Tibia; Osteoarthritis, Knee; Knee Prosthesis
PubMed: 36440506
DOI: 10.1111/os.13595 -
Journal of Orthopaedic Research :... Jun 2023This study aimed to (1) measure acetabular sector angle (ASA) from proximal to distal positions along the axial femoral head axis, (2) identify acetabular deficiency...
This study aimed to (1) measure acetabular sector angle (ASA) from proximal to distal positions along the axial femoral head axis, (2) identify acetabular deficiency patterns, and (3) correlate ASA at different axial positions with other radiological measurements in acetabular dysplasia. We identified 30 hips with dysplasia (lateral center edge angle [LCEA] <20°) and 30 hips without dysplasia (LCEA >25°) from a retrospective cohort. Anterior and posterior ASA (AASA, PASA) were measured in the axial computed tomography plane through the femoral head center (equatorial) and two axial positions above the equatorial line (intermediate and proximal). Deficiency patterns were identified using ASA cut-off values determined from receiver operating characteristic curves. Pearson's coefficients were used for correlations. Compared to non-dysplastic hips, AASA in dysplastic hips was significantly smaller in all levels: equatorial (46.1 ± 7.3 vs. 54.9 ± 8.5,° p < 0.001), intermediate (62.1 ± 11.2 vs. 69.0 ± 10.6,° p = 0.02), and proximal (102.9 ± 14.2 vs. 128.3 ± 23.0,° p < 0.001). According to proximal ASA (Pro-ASA) cut-off values in dysplastic hips, global deficiency was most prevalent (19/30, 63.3%), followed by anterior (6/30, 20%) and posterior (3/30, 10%) deficiency. There were strong correlations between acetabular anteversion and Eq-AASA (r = -0.74, p < 0.001) and LCEA and pro-PASA (r = 0.82, p < 0.001). Clinical significance: Acetabular sector angle provides insight into acetabular morphology and patterns of deficiency, providing essential information for precise acetabular reorientation.
Topics: Humans; Retrospective Studies; Femur Head; Acetabulum; Hip Dislocation, Congenital; Hip Dislocation; Hip Joint
PubMed: 36370137
DOI: 10.1002/jor.25479 -
JNMA; Journal of the Nepal Medical... Nov 2020Chordoma is a rare and locally aggressive tumor that arises from the notochordal remnants and has an incidence of 0.1/100000 per year. It has a predilection for the...
Chordoma is a rare and locally aggressive tumor that arises from the notochordal remnants and has an incidence of 0.1/100000 per year. It has a predilection for the axial skeleton and is the most common primary malignant tumor of sacrum. The mainstay of treatment is wide surgical excision but there is a risk of recurrence due to the infiltrating nature of the tumor. Here, we report a case of a 56-years male who complained of pain over his sacral region for the past two years along with episodic urinary symptoms, constipation, and weakness of both legs. Seven years after undergoing surgery and radiotherapy for his sacral chordoma, he was diagnosed with recurrent sacral chordoma and planned for reoperation. Subtotal excision of the chordoma was done which significantly alleviated his symptoms postoperatively. Timely intervention helps to improve the quality of life in patients with either primary or recurrent sacral chordomas.
Topics: Chordoma; Humans; Male; Neoplasm Recurrence, Local; Quality of Life; Sacrococcygeal Region; Sacrum
PubMed: 34506409
DOI: 10.31729/jnma.5401 -
The Journal of Rheumatology Nov 2023Axial spondyloarthritis (axSpA) is associated with decreased function and mobility of patients as a result of inflammation and radiographic damage. The Epionics SPINE...
OBJECTIVE
Axial spondyloarthritis (axSpA) is associated with decreased function and mobility of patients as a result of inflammation and radiographic damage. The Epionics SPINE device (ES), an electronic device that objectively measures spinal mobility, including range of motion (RoM) and speed (ie, range of kinematics [RoK]) of movement, has been clinically validated in axSpA. We investigated the performance of the ES relative to radiographic damage in the axial skeleton of patients with axSpA.
METHODS
A total of 103 patients with axSpA, 31 with nonradiographic axSpA (nr-axSpA) and 72 with radiographic axSpA (r-axSpA), were consecutively examined. Conventional radiographs of the spine (including presence, number, and location of syndesmophytes) and the sacroiliac joints (SIJs; rated by the modified New York criteria) were analyzed with the ES. Function and mobility were assessed using analyses of covariance and Spearman correlation.
RESULTS
The number of syndesmophytes correlated positively with Bath Ankylosing Spondylitis Metrology Index scores ( 0.38, = 0.02) and correlated negatively with chest expansion ( -0.39, = 0.02) and ES measurements (-0.53 ≤ ≤ -0.34, all < 0.03), except for RoM and RoK regarding rotation and RoK for extension of the lumbar and thoracic spines. In the radiographic evaluation of the SIJs, the extent of damage correlated negatively with ES scores and metric measurements (-0.49 ≤ ≤ -0.33, all < 0.001). Patients with r-axSpA, as compared to those with nr-axSpA, showed significantly worse ES scores for RoM, RoK, and chest expansion.
CONCLUSION
The ES scores, in accordance with mobility measurements, correlated well with the presence and extent of radiographic damage in the spine and the SIJs. As expected, patients with r-axSpA had more severe impairments than those with nr-axSpA.
Topics: Humans; Spondylarthritis; Non-Radiographic Axial Spondyloarthritis; Clinical Relevance; Spondylitis, Ankylosing; Sacroiliac Joint
PubMed: 37061230
DOI: 10.3899/jrheum.2022-1240 -
Sensors (Basel, Switzerland) May 2023Wireless accelerometers with various operating ranges have been used to measure tibial acceleration. Accelerometers with a low operating range output distorted signals...
Wireless accelerometers with various operating ranges have been used to measure tibial acceleration. Accelerometers with a low operating range output distorted signals and have been found to result in inaccurate measurements of peaks. A restoration algorithm using spline interpolation has been proposed to restore the distorted signal. This algorithm has been validated for axial peaks within the range of 15.0-15.9 . However, the accuracy of peaks of higher magnitude and the resultant peaks have not been reported. The purpose of the present study is to evaluate the measurement agreement of the restored peaks using a low-range accelerometer (±16 ) against peaks sampled using a high-range accelerometer (±200 ). The measurement agreement of both the axial and resultant peaks were examined. In total, 24 runners were equipped with 2 tri-axial accelerometers at their tibia and completed an outdoor running assessment. The accelerometer with an operating range of ±200 was used as reference. The results of this study showed an average difference of -1.40 ± 4.52 and -1.23 ± 5.48 for axial and resultant peaks. Based on our findings, the restoration algorithm could skew data and potentially lead to incorrect conclusions if used without caution.
Topics: Tibia; Acceleration; Algorithms; Running
PubMed: 37430524
DOI: 10.3390/s23104609 -
Journal of Orthopaedic Research :... Apr 2023The sacroiliac joint (SIJ) constitutes the predominant pain source following lumbar or lumbosacral fusion. Although studies have investigated the biomechanical patterns...
The sacroiliac joint (SIJ) constitutes the predominant pain source following lumbar or lumbosacral fusion. Although studies have investigated the biomechanical patterns of SIJ behaviors after lumbosacral fusion, the relationship between ligament strain and SIJ pain following lumbosacral fusion remains unclear. The present study developed a three-dimensional finite element model including L4, L5, sacrum, ilium, SIJ, and seven mainly ligaments. After successful validation, the model was used to investigate the biomechanics of SIJ and ligaments in simulating lumbosacral fusion process. Our results showed that small motion in a stable SIJ may significantly increases the contact pressure and stress of the SIJ, which increase the maximum contact pressure by 171%, 676%, 199%, and 203% and stress by 130%, 424%, 168%, and 241% for flexion, extension, bending, and axial rotation, respectively. An increase in contact pressure and stress in SIJ possibly causes pain at the SIJ, especially in extension and axial rotation. A comparison between the lumbosacral and intact models exhibited the maximum strain increase in the iliosacral ligament (ISL) and the ileal ligament (IL) under all loading conditions. The present study suggests that after lumbosacral fusion process, the ligament sudden increase or decrease is likely to lead sprain or strain ligament, especially ISL and IL thereby causing SIJ pain. This study may contribute to understand the relationship between SIJ ligaments and SIJ pain.
Topics: Humans; Sacroiliac Joint; Finite Element Analysis; Biomechanical Phenomena; Sacrum; Low Back Pain; Ligaments, Articular; Arthralgia; Spinal Fusion; Lumbar Vertebrae
PubMed: 35780392
DOI: 10.1002/jor.25411 -
Journal of Orthopaedic Surgery and... Dec 2022Previous studies on dynamic impingement of nerve root in cervical spondylotic radiculopathy (CSR) have focused on effect of cervical spine motion (CSM) on dimensional...
Effect of cervical spine motion on displacement of posterolateral annulus fibrosus in cervical spondylotic radiculopathy with contained posterolateral disc herniation: a three-dimensional finite element analysis.
BACKGROUND
Previous studies on dynamic impingement of nerve root in cervical spondylotic radiculopathy (CSR) have focused on effect of cervical spine motion (CSM) on dimensional changes of intervertebral foramen. However, there are few studies to investigate effect of CSM on displacement of posterolateral intervertebral disc until now. The present study aimed to investigate effect of CSM on displacement of posterolateral annulus fibrosus (AF) in CSR with contained posterolateral disc herniation.
METHODS
A C5-C6 CSR finite element model with unilateral contained posterolateral disc herniation was generated based on validated C5-C6 normal finite element model. Forward and backward displacement distributions of posterolateral AFs in CSR model and normal model were compared. Changes in forward and backward displacement magnitudes of posterolateral AFs of the herniated side and the healthy side in CSR model, with respect to those of the ipsilateral posterolateral AFs in normal model, were compared. The comparisons were performed under flexion, extension, lateral bendings and axial rotations.
RESULTS
There was no difference in deformation trend of posterolateral AF between CSR model and normal model. Bilateral posterolateral AFs mainly moved forward during flexion and backward during extension. Left posterolateral AF mainly moved backward and right posterolateral AF forward during left lateral bending and left axial rotation. Left posterolateral AF mainly moved forward and right posterolateral AF backward during right lateral bending and right axial rotation. However, with respect to forward and backward displacement magnitudes of the ipsilateral posterolateral AFs in normal model, those of the herniated side increased relatively significantly compared with those of the healthy side in CSR model.
CONCLUSIONS
Flexion, lateral bending to the healthy side and axial rotation to the healthy side make posterolateral AF of the herniated side mainly move forward, whereas extension, lateral bending to the herniated side and axial rotation to the herniated side make it mainly move backward. These data may help select CSM or positions to diagnose and treat CSR with contained posterolateral disc herniation. Increase in deformation amplitude of posterolateral AF of the herniated side may also be the reason for dynamic impingement of nerve root in CSR with contained posterolateral disc herniation.
Topics: Humans; Intervertebral Disc Displacement; Annulus Fibrosus; Finite Element Analysis; Radiculopathy; Biomechanical Phenomena; Spondylosis; Cervical Vertebrae; Intervertebral Disc; Range of Motion, Articular
PubMed: 36528646
DOI: 10.1186/s13018-022-03450-5