pinecone/core-2020-05-10-deduplication huggingface dataset:
Bacterial adherence to separated modular components in joint prosthesis: A clinical study

El pdf del artículo es la versión pre-print.-- et al.Bacterial adherence on total joint replacement implants may lead to biofilm formation and implant-related osteoarticular infection. It is unclear if different biomaterials in the prosthetic components are more prone to facilitate this bacterial adherence, although ultrahigh molecular weight polyethylene (UHMWPE) component exchange in modular systems has been clinically utilized in the early management of these infections. To clarify if the amount of clinically adhered microorganisms was related to the material or the component, we investigated retrieved implants from infected joint replacements. Thirty-two patients were revised after confirmed implant-related infection through positive cultures. Eighty-seven total joint components (hip and knee) were obtained and separately sonicated following a previously published protocol. Cultures were quantified, and detected colony forming units (CFU) were adjusted according to the component surface and compared based on the component material and location. Variable adherence of bacteria to chrome cobalt alloys, UHMWPE, hydroxyapatite coated components, and titanium alloys. The commonest isolated organisms were Staphylococcus epidermidis (23 of 87 components) and Staphylococcus aureus (10 of 87). Twelve components did not show any microorganism adhered despite location in an infected joint, with positive cultures in other components. A mixed linear model adjusted for random effects (the random effect being the infected patient) obtained convergence for the CFU/mm 2 variable, but could not confirm a significantly higher adherence to a particular component or to a particular biomaterial. Therefore, the bacterial adherence primarily depends on the infective microorganism and the response of each individual patient, rather than materials or components. © Copyright © 2012 Orthopaedic Research Society.This study was partly funded by a grant from the Spanish Ministry of Science (FUNCOAT-CSD2008-00023).Peer Reviewe
Two-week joint mobilization intervention improves self-reported function, range of motion, and dynamic balance in those with chronic ankle instability

We examined the effect of a 2-week anterior-to-posterior ankle joint mobilization intervention on weight-bearing dorsiflexion\ud
range of motion (ROM), dynamic balance, and self-reported function in subjects with chronic ankle instability (CAI). In this prospective\ud
cohort study, subjects received six Maitland Grade III anterior-to-posterior joint mobilization treatments over 2 weeks. Weightbearing\ud
dorsiflexion ROM, the anterior, posteromedial, and posterolateral reach directions of the Star Excursion Balance Test (SEBT),\ud
and self-reported function on the Foot and Ankle Ability Measure (FAAM) were assessed 1 week before the intervention (baseline),\ud
prior to the first treatment (pre-intervention), 24–48 h following the final treatment (post-intervention), and 1 week later (1-week\ud
follow-up) in 12 adults (6 males and 6 females) with CAI. The results indicate that dorsiflexion ROM, reach distance in all directions of\ud
the SEBT, and the FAAM improved (p < 0.05 for all) in all measures following the intervention compared to those prior to the intervention.\ud
No differences were observed in any assessments between the baseline and pre-intervention measures or between the postintervention\ud
and 1-week follow-up measures (p > 0.05). These results indicate that the joint mobilization intervention that targeted\ud
posterior talar glide was able to improve measures of function in adults with CAI for at least 1 week
Selective and Non-Selective Cyclooxygenase Inhibitors Delay Stress Fracture Healing in the Rat Ulna

Anti-inflammatory drugs are widely used to manage pain associated with stress fractures (SFxs), but little is known about their effects on healing of those injuries. We hypothesized that selective and non-selective anti-inflammatory treatments would retard the healing of SFx in the rat ulna. SFxs were created by cyclic loading of the ulna in Wistar rats. Ulnae were harvested 2, 4 or 6 weeks following loading. Rats were treated with non-selective NSAID, ibuprofen (30?mg/kg/day); selective COX-2 inhibition, [5,5-dimethyl-3-3 (3 fluorophenyl)-4-(4 methylsulfonal) phenyl-2 (5H)-furanone] (DFU) (2.0?mg/kg/day); or the novel c5a anatagonist PMX53 (10?mg/kg/day, 4 and 6 weeks only); with appropriate vehicle as control. Quantitative histomorphometric measurements of SFx healing were undertaken. Treatment with the selective COX-2 inhibitor, DFU, reduced the area of resorption along the fracture line at 2 weeks, without affecting bone formation at later stages. Treatment with the non-selective, NSAID, ibuprofen decreased both bone resorption and bone formation so that there was significantly reduced length and area of remodeling and lamellar bone formation within the remodeling unit at 6 weeks after fracture. The C5a receptor antagonist PMX53 had no effect on SFx healing at 4 or 6 weeks after loading, suggesting that PMX53 would not delay SFx healing. Both selective COX-2 inhibitors and non-selective NSAIDs have the potential to compromise SFx healing, and should be used with caution when SFx is diagnosed or suspected.Full Tex
Wear and wear measurement in total and hemi hip replacement

List of papers. Papers 1, 3 and 4 are removed from the thesis due to publisher restrictions.

Paper 1 Dahl, J. Figved, W. Snorrason, F. Nordsletten L. Røhrl SM. The Center Index Method. An alternative for wear measurement with radiostereometry (RSA). J Orthop Res 2012; 31(3):480-484 <a href="http://dx.doi.org/10.1002/jor.22241">doi:10.1002/jor.22241</a>

Paper 2 Dahl, J. Nivbrandt, B. Søderlund, P, Nordsletten, L. Røhrl, SM. Less wear with aluminium-oxide heads than cobalt-chrome heads with cemented ultra high molecular weight polyethylene cups. A ten-year follow-up with radiostereometry. Int Orthop. 2012; 36(3): 485-90. <a href="http://dx.doi.org/10.1007/s00264-011-1334-3">doi:10.1007/s00264-011-1334-3</a>

Paper 3 Dahl, J. Snorrason, F. Nordsletten, L. Røhrl, SM. More than 50% reduction of polyethylene wear in uncemented acetabular components using Alumina heads compared to Cobalt-Chrome heads after 10 years. A prospective RSA study. Acta Orthop 2013;84(4): Epub 2013/06/26 <a href="http://dx.doi.org/10.3109/17453674.2013.810516">doi:10.3109/17453674.2013.810516</a> Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License

Paper 4 Figved, W. Dahl, J. Snorrason, F. Frihagen, F. Røhrl SM. Madsen, JE. Nordsletten L. Radiostereometric analysis of hemiarthroplasties of the hip - a new and highly precise method for measurements of cartilage wear in the human body. Osteoarthritis Cartilage 2012; 20(1): 36-42. <a href="http://dx.doi.org/10.1016/j.joca.2011.11.006">doi:10.1016/j.joca.2011.11.006</a
Evaluation of factors affecting tibial bone strain after unicompartmental knee replacement

Persistent pain is an important cause of patient dissatisfaction after unicompartmental knee replacement (UKR) and has been correlated with localized tibial strain. However, the factors that influence these strains are not well understood. To address this issue, we created finite element models to examine the effect on tibial strain of: (1) muscle forces (estimated using instrumented knee data) acting on attachment sites on the proximal tibia, (2) UKR implantation, (3) loading position, and (4) changes in gait pattern. Muscle forces acting on the tibia had no significant influence on strains within the periprosthetic region, but UKR implantation increased strain by 20%. Strain also significantly increased if the region of load application was moved >3 mm medially. The strain within the periprosthetic region was found to be dependent on gait pattern and was influenced by both medial and lateral loads, with the medial load having a greater effect (regression coefficients: medial = 0.74, lateral = 0.30). These findings suggest that tibial strain is increased after UKR and may be a cause of pain. It may be possible to reduce pain through modification of surgical factors or through altered gait patterns
Selective laser melting-produced porous titanium scaffolds regenerate bone in critical size cortical bone defects

Porous titanium scaffolds have good mechanical properties that make them an interesting bone substitute material for large bone defects. These scaffolds can be produced with selective laser melting, which has the advantage of tailoring the structure's architecture. Reducing the strut size reduces the stiffness of the structure and may have a positive effect on bone formation. Two scaffolds with struts of 120-μm (titanium-120) or 230-μm (titanium-230) were studied in a load-bearing critical femoral bone defect in rats. The defect was stabilized with an internal plate and treated with titanium-120, titanium-230, or left empty. In vivo micro-CT scans at 4, 8, and 12 weeks showed more bone in the defects treated with scaffolds. Finally, 18.4 ± 7.1 mm3(titanium-120, p = 0.015) and 18.7 ± 8.0 mm3(titanium-230, p = 0.012) of bone was formed in those defects, significantly more than in the empty defects (5.8 ± 5.1 mm3). Bending tests on the excised femurs after 12 weeks showed that the fusion strength reached 62% (titanium-120) and 45% (titanium-230) of the intact contralateral femurs, but there was no significant difference between the two scaffolds. This study showed that in addition to adequate mechanical support, porous titanium scaffolds facilitate bone formation, which results in high mechanical integrity of the treated large bone defects. Copyrigh
Hip abduction can prevent posterior edge loading of hip replacements

Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted.Full Tex
Integrin-mediated interactions with extracellular matrix proteins for nucleus pulposus cells of the human intervertebral disc.

The extracellular matrix (ECM) of the human intervertebral disc is rich in molecules that interact with cells through integrin-mediated attachments. Porcine nucleus pulposus (NP) cells have been shown to interact with laminin (LM) isoforms LM-111 and LM-511 through select integrins that regulate biosynthesis and cell attachment. Since human NP cells lose many phenotypic characteristics with age, attachment and interaction with the ECM may be altered. Expression of LM-binding integrins was quantified for human NP cells using flow cytometry. The cell-ECM attachment mechanism was determined by quantifying cell attachment to LM-111, LM-511, or type II collagen after functionally blocking specific integrin subunits. Human NP cells express integrins β1, α3, and α5, with over 70% of cells positive for each subunit. Blocking subunit β1 inhibited NP cell attachment to all substrates. Blocking subunits α1, α2, α3, and α5 simultaneously, but not individually, inhibits NP cell attachment to laminins. While integrin α6β1 mediated porcine NP cell attachment to LM-111, we found integrins α3, α5, and β1 instead contributed to human NP cell attachment. These findings identify integrin subunits that may mediate interactions with the ECM for human NP cells and could be used to promote cell attachment, survival, and biosynthesis in cell-based therapeutics
Impact of direct cell co-cultures on human adipose-derived stromal cells and nucleus pulposus cells

Biologic and cellular treatment strategies aiming for curing intervertebral disc degeneration (IDD) have been proposed recently. Given the convenient availability and expansion potential, adipose-derived stromal cells (ADSCs) might be an ideal cell candidate. However, the interaction between ADSCs and nucleus pulposus (NP) cells still remains ambiguous, especially in direct co-cultures of the two types of cells. Nevertheless, NP markers in ADSCs after co-cultures were unidentified. Here, we addressed the interaction of human ADSCs and NP cells in a direct co-culture system for the first time. As a result, ADSCs could differentiate to the NP cell phenotype with a significant up-regulated expression of multiple genes and proteins in extracellular matrix (ECM) (SOX9, COL2A1, ACAN, and COL6A2), relative NP markers (FOXF1, PAX1, CA12, and HBB) and pertinent growth factors (CDMP-1, TGF-beta1, IGF-1, and CTGF). Moreover, the gene expression of COL2A1, ACAN, and COL6A2 of degenerate NP cells was also up-regulated. Collectively, these results suggest that direct co-cultures of ADSCs and NP cells may exert a reciprocal impact, that is, both stimulating ADSCs differentiation to the NP cell phenotype and inducing NP cells to regain functional phenotype. Accordingly, ADSCs might be a potential candidate in the development of cellular treatment strategies for IDD.published_or_final_versio
Three-dimensional implant position and orientation after total knee replacement performed with patient-specific instrumentation systems

Patient-specific instrumentation systems are entering into clinical practice in total knee replacement, but validation tests have yet to determine the accuracy of replicating computer-based plans during surgery. We performed a fluoroscopic analysis to assess the final implant location with respect to the corresponding preoperative plan. Forty-four patients were analyzed after using a patient-specific system based on CT and MRI. Computer aided design implant models and models of the femur and tibia bone portions, as for the preoperative plans, were provided by the manufacturers. Two orthogonal fluoroscopic images of each knee were taken after surgery for pseudo-biplane imaging; 3D component locations with respect to the corresponding bones were estimated by a shape-matching technique. Assuming that the corresponding values at the preoperative plan were equal to zero, discrepancies were taken as an indication of accuracy for the systems. A repeatability test revealed that the technique was reliable within 1 mm and 1°. The maximum discrepancies for all the patients for the femoral component were 5.9 mm in a proximo-distal direction and 4.2° in flexion. Good matching was found between final implantations and preoperative plans with mean discrepancies smaller than 3.1 mm and 1.9°.status: publishe
How many different types of femora are there in primary hip osteoarthritis?:An active shape modeling study

We assessed the variation in proximal femoral canal shape and its association with geometric and demographic parameters in primary hip OA. In a retrospective cohort study, the joint geometry of the proximal femur was evaluated on radiographs and corresponding CT scans of 345 consecutive patients with end-stage hip OA. Active shape modeling (ASM) was performed to assess the variation in endosteal shape of the proximal femur. To identify natural groupings of patients, hierarchical cluster analysis of the shape modes was used. ASM identified 10 independent shape modes accounting for >96% of the variation in proximal femoral canal shape within the dataset. Cluster analysis revealed 10 specific shape clusters. Significant differences in geometric and demographic parameters between the clusters were observed. ASM and subsequent cluster analysis have the potential to identify specific morphological patterns of the proximal femur despite the variability in proximal femoral anatomy. The study identified patterns of proximal femoral canal shape in hip OA that allow a comprehensive classification of variation in shape and its association with joint geometry. Our data may improve future stem designs that will optimize stem fit and simultaneously allow individual restoration of hip biomechanics
Effect of increased quadriceps tensile stiffness on peak anterior cruciate ligament strain during a simulated pivot landing

ACL injury prevention programs often involve strengthening the knee muscles. We posit that an unrecognized benefit of such training is the associated increase in the tensile stiffness of the hypertrophied muscle. We tested the hypothesis that an increased quadriceps tensile stiffness would reduce peak anteromedial bundle (AM‐)ACL relative strain in female knees. Twelve female cadaver knees were subjected to compound impulsive two‐times body weight loads in compression, flexion, and internal tibial torque beginning at 15° flexion. Knees were equipped with modifiable custom springs to represent the nonlinear rapid stretch behavior of a normal and increased stiffness female quadriceps (i.e., 33% greater stiffness). Peak AM‐ACL relative strain was measured using an in situ transducer while muscle forces and tibiofemoral kinematics and kinetics were recorded. A 3D ADAMS™ dynamic biomechanical knee model was used in silico to interpret the experimental results which were analyzed using a repeated‐measures Wilcoxon test. Female knees exhibited a 16% reduction in peak AM‐ACL relative strain and 21% reduction in change in flexion when quadriceps tensile stiffness was increased by 33% (mean (SD) difference: 0.97% (0.65%),  p  = 0.003). We conclude that increased quadriceps tensile stiffness reduces peak ACL strain during a controlled study simulating a pivot landing. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:423–430, 2014
Changes in macrophage phenotype and induction of epithelial‐to‐mesenchymal transition genes following acute Achilles tenotomy and repair

Tendon injuries occur frequently in physically active individuals, but the clinical outcomes for these injuries can be poor. In many injured tissues the repair process is orchestrated by two types of cells, macrophages and fibroblasts. Macrophages, which have both pro‐inflammatory (M1) and anti‐inflammatory (M2) phenotypes, can directly participate in tissue remodeling and direct the response of other cells through the secretion of cytokines and growth factors. In many organ systems, epithelial cells can trans‐differentiate into fibroblasts, which can then regenerate damaged ECM. This process is triggered via activation of epithelial‐to‐mesenchymal transition (EMT) signaling programs. Most tendons are surrounded by sheets of epithelial cells, and these tissue layers could provide a source of fibroblasts to repair injured tendons. To gain greater insight into the biology of tendon repair, we performed a tenotomy and repair in Achilles tendons of adult rats and determined changes in macrophage phenotype, and ECM‐ and EMT‐related genes over a 4‐week time course. The results from this study suggest that changes in macrophage phenotype and activation of EMT‐related programs likely contribute to the degradation and subsequent repair of injured tendon tissue. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:944–951, 2014
Effects of biceps tension and superior humeral head translation on the glenoid labrum

We sought to understand the effects of superior humeral head translation and load of the long head of biceps on the pathomechanics of the superior glenoid labrum by predicting labral strain. Using micro‐CT cadaver images, a finite element model of the glenohumeral joint was generated, consisting of humerus, glenoid bone, cartilages, labrum, and biceps tendon. A glenohumeral compression of 50 N and biceps tensions of 0, 22, 55, and 88 N were applied. The humeral head was superiorly translated from 0 to 5 mm in 1‐mm increments. The highest labral strain occurred at the interface with the glenoid cartilage and bone beneath the origin of the biceps tendon. The maximum strain was lower than the reported failure strain. The humeral head motion had relatively greater effect than biceps tension on the increasing labral strain. This supports the mechanistic hypothesis that superior labral lesions result mainly from superior migration of the humeral head, but also from biceps tension. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1424–1429, 2014
Transsacral screw safe zone size by sacral segmentation variations

Variations in sacral segmentation may preclude safe placement of transsacral screws for posterior pelvis fixation. We developed a novel automated 3D technique to determine the safe zone size for transsacral screws in the upper two sacral segments in 526 adult pelvis computed tomography scans. Safe zone sizes were then compared by gender and sacral segmentation variations (number of neuroforamen and the presence/absence of lumbosacral transitional vertebrae, ±LSTV). Ten millimeters was used as the safety threshold for a large screw. 3 (0.6%), 366 (70%), and 157 (30%) sacra had 3, 4, or 5 neuroforamen, respectively. Eighty‐eight (17%) were +LSTV. Safe zone size depended on gender, number of neuroforamen in −LSTV sacra and presence of LSTV (p < 0.001) but not on the uni‐ or bilateral nature of the LSTV. 17% of −LSTV sacra were below the safety threshold in S1, 27% in S2, whereas 3% of +LSTV sacra were below in S1, 74% in S2. Of −LSTV sacra that cannot take an S1 screw safely, 77% can do so in S2, leaving only 4% of sacra that cannot accommodate a screw safely in either upper segment. The results demonstrate a predictable pattern of safe zone size based on gender and sacral segmentation variations. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:277–282, 2015
Muscle optimization techniques impact the magnitude of calculated hip joint contact forces

In musculoskeletal modelling, several optimization techniques are used to calculate muscle forces, which strongly influence resultant hip contact forces (HCF). The goal of this study was to calculate muscle forces using four different optimization techniques, i.e., two different static optimization techniques, computed muscle control (CMC) and the physiological inverse approach (PIA). We investigated their subsequent effects on HCFs during gait and sit to stand and found that at the first peak in gait at 15-20% of the gait cycle, CMC calculated the highest HCFs (median 3.9 times peak GRF (pGRF)). When comparing calculated HCFs to experimental HCFs reported in literature, the former were up to 238% larger. Both static optimization techniques produced lower HCFs (median 3.0 and 3.1 pGRF), while PIA included muscle dynamics without an excessive increase in HCF (median 3.2 pGRF). The increased HCFs in CMC were potentially caused by higher muscle forces resulting from co-contraction of agonists and antagonists around the hip. Alternatively, these higher HCFs may be caused by the slightly poorer tracking of the net joint moment by the muscle moments calculated by CMC. We conclude that the use of different optimization techniques affects calculated HCFs, and static optimization approached experimental values best. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.status: publishe