The effect of bondline thickness on the strength of adhesively bonded single lap joints (SLJs) is still an open issue. According to the analytical methods and also finite element (FE) results, ...increasing the adhesive thickness causes a more uniform stress and strain distribution along the adhesive layer and consequently leads to higher strength of the SLJs, while the experimental data has shown lower strength for joints with thicker bondlines. This paper deals with the effect of the adhesive thickness on the strength of SLJs from the perspective of the longitudinal strain along the adhesive mid-plane. The longitudinal strain is a recently proposed failure parameter which should be measured along the adhesive mid-plane, at a specific distance away from the joint bonding end. The FE results showed that under a constant tensile load, the values of longitudinal strain along the adhesive mid-plane, increase with adhesive thickness. It could be concluded that the introduced failure parameter could take into account the decrease in joint strength due to an increase in bondline thickness. Some experiments on SLJs with different adhesive thicknesses and bonding lengths were conducted to validate the method. Good correlation between the experimental results and the predictions were seen. The method was also applied on experimental results published by other researchers. The results again showed that the new strain based method could well consider the strength reduction of SLJs due to increasing adhesive thickness.
Whether using magnetic resonance imaging (MRI) to guide treatment in patients with rheumatoid arthritis (RA) improves disease activity and slows joint damage progression is unknown.
To determine ...whether an MRI-guided treat-to-target strategy vs a conventional clinical treat-to-target strategy improves outcomes in patients with RA in clinical remission.
Two-year, randomized, multicenter trial conducted at 9 hospitals in Denmark. Two hundred patients with RA in clinical remission (disease activity score in 28 joints-C-reactive protein DAS28-CRP <3.2 and no swollen joints) were enrolled between April 2012 and June 2015. The final follow-up visit was April 2017.
Patients were randomly allocated (1:1) to an MRI-guided vs a conventional treat-to-target strategy. In the MRI-guided group, the treatment goal was absence of MRI bone marrow edema combined with clinical remission, defined as DAS28-CRP of 3.2 or less and no swollen joints. In the conventional group, the treatment goal was clinical remission.
Co-primary outcomes were proportions of patients achieving DAS28-CRP remission (DAS28-CRP <2.6) and with no radiographic progression (no increase in total van der Heijde-modified Sharp score) at 24 months. Significance testing for the primary outcome was based on 1-sided testing. Secondary outcomes were clinical and MRI measures of disease activity, physical function, and quality of life.
Of 200 patients randomized (133 women 67%; mean SD age, 61.6 10.5 years; median baseline DAS28-CRP, 1.9 interquartile range, 1.7-2.2; van der Heijde-modified Sharp score, 18.0 interquartile range, 7.0-42.5), 76 patients (76%) in the MRI-guided group and 95 (95%) in the conventional group completed the study. Of these, 64 (85%) vs 83 (88%), respectively, reached the primary clinical end point (risk difference, -4.8% 1-sided 95% CI, -13.6% to + ∞; 1-sided P = .19) and 49 (66%) vs 58 (62%), respectively, reached the primary radiographic end point (risk difference, 4.7% 1-sided 95% CI, -7.0% to + ∞; 1-sided P = .25). Of 10 key secondary end points, 8 were null and 2 showed statistically significant benefit for the MRI treat-to-target group. Seventeen patients (17%) in the MRI-guided treat-to-target group and 6 patients (6%) in the conventional treat-to-target group experienced serious adverse events.
Among patients with RA in clinical remission, an MRI-guided treat-to-target strategy compared with a conventional treat-to-target strategy did not result in improved disease activity remission rates or reduce radiographic progression. These findings do not support the use of an MRI-guided strategy for treating patients with RA.
ClinicalTrials.gov Identifier: NCT01656278.
Staphylococcus comprises up to two-thirds of all pathogens in orthopaedic implant infections with two species respectively Staphylococcus aureus and Staphylococcus epidermidis, being the predominate ...etiological agents isolated. Further, with the emergence of methicillin-resistant S. aureus (MRSA), treatment of S. aureus implant infections has become more difficult, thus representing a devastating complication. Use of local delivery system consisting of S.aureus specific phage along with linezolid (incorporated in biopolymer) allowing gradual release of the two agents at the implant site represents a new, still unexplored treatment option (against orthopaedic implant infections) that has been studied in an animal model of prosthetic joint infection. Naked wire, hydroxypropyl methylcellulose (HPMC) coated wire and phage and /or linezolid coated K-wire were surgically implanted into the intra-medullary canal of mouse femur bone of respective groups followed by inoculation of S.aureus ATCC 43300(MRSA). Mice implanted with K-wire coated with both the agents i.e phage as well as linezolid (dual coated wires) showed maximum reduction in bacterial adherence, associated inflammation of the joint as well as faster resumption of locomotion and motor function of the limb. Also, all the coating treatments showed no emergence of resistant mutants. Use of dual coated implants incorporating lytic phage (capable of self-multiplication) as well as linezolid presents an attractive and aggressive early approach in preventing as well as treating implant associated infections caused by methicillin resistant S. aureus strains as assessed in a murine model of experimental joint infection.
The investigation conducted in this study focused on assessing the withdrawal resistance of T-joints and the bending moment capacity in the tension and compression of corner joints. For samples, ...preparation glued-in loose tenons (Domino dowels) and dismountable connectors were used as connecting elements. The joints were made of European beech wood and a D3-grade PVAc adhesive was utilized for bonding. The effect of the joint type, the shoulders’ bonding, and the load application direction were investigated. The test results revealed that the withdrawal resistance of Domino dowel joints exhibited twice the strength compared to Domino connectors. Moreover, the presence of a bonded area on the shoulders did not significantly impact the strength of the joints. In the case of corner joints, the bending moment capacity in compression was notably influenced by the bond line on the shoulders, although such an effect was not significant in tension. Domino dowel joints provided a robust and reliable permanent connection between wooden elements, surpassing Domino connectors; however, in both cases, the strength values exceeded those of conventional dowels and cam lock connector joints.
Osteoarthritis is a debilitating joint disease affecting nearly 30 million people for which there are no disease-modifying therapies. Several drugs that have failed clinical trials have shown ...inefficient and inadequate delivery to target cells. Anabolic growth factors are one class of such drugs that could be disease-modifying if delivered directly to chondrocytes, which reside deep within dense, anionic cartilage tissue. To overcome this biological barrier, we conjugated a growth factor to a cationic nanocarrier for targeted delivery to chondrocytes and retention within joint cartilage after direct intra-articular injection. The nanocarrier uses reversible electrostatic interactions with anionic cartilage tissue to improve tissue binding, penetration, and residence time. Amine terminal polyamidoamine (PAMAM) dendrimers were end functionalized with variable molar ratios of poly(ethylene glycol) (PEG) to control surface charge. From this small family of variably PEGylated dendrimers, an optimal formulation showing 70% uptake into cartilage tissue and 100% cell viability was selected. When conjugated to insulin-like growth factor 1 (IGF-1), the dendrimer penetrated bovine cartilage of human thickness within 2 days and enhanced therapeutic IGF-1 joint residence time in rat knees by 10-fold for up to 30 days. In a surgical model of rat osteoarthritis, a single injection of dendrimer-IGF-1 rescued cartilage and bone more effectively than free IGF-1. Dendrimer-IGF-1 reduced width of cartilage degeneration by 60% and volumetric osteophyte burden by 80% relative to untreated rats at 4 weeks after surgery. These results suggest that PEGylated PAMAM dendrimer nanocarriers could improve pharmacokinetics and efficacy of disease-modifying osteoarthritis drugs in the clinic.
Background
Plano‐valgus is a common alteration of the paediatric foot, characterized by valgus hindfoot, foot pronation and drop of the medial longitudinal arch. Despite their importance in the ...diagnosis and classification of plano‐valgus foot condition, little information is available on functional alterations of the major joints spanning the medial longitudinal arch – i.e. midtarsal and tarso‐metatarsal. Aim of the study was to provide objective description of the alterations in plano‐valgus midfoot joints with respect to those in an age‐matched normally‐developed feet population.
Methods
Twenty adolescents (13.3 ± 0.8 years) with bilateral plano‐valgus feet underwent clinical examination and were gait‐analysed via a validated 4‐segment foot model. This allowed to measure static foot posture, kinematics of the main foot joints, and medial longitudinal arch deformation during walking at comfortable speed. Range of motion and temporal profiles of joint rotations were compared to those from a control population of age‐matched adolescents with normally‐developed feet.
Results
The plano‐valgus midtarsal joint was more dorsiflexed, everted and abducted than that in the control group, and showed reduced sagittal‐plane RoM (plano‐valgus = 15.9 degrees; control = 22.2 degrees; P < 0.01). The tarso‐metarsal joint was more plantarflexed and adducted, and showed larger frontal‐plane RoM. The MLA showed larger RoM and was lower throughout the stance phase of the gait cycle.
Conclusion
Significant postural and kinematic alterations are present at the midtarsal and tarso‐metarsal joints of adolescents with plano‐valgus feet. Objective identification and quantification of plano‐valgus foot alterations, via non‐invasive gait‐analysis, is relevant to improving the diagnosis of this condition and to evaluating the effect of conservative treatments and of surgical corrections by different techniques.
Purpose The purpose of this study was to evaluate the safety and efficacy of intra-articular corticosteroid injections (IACIs) of the temporomandibular joint (TMJ) in children with juvenile ...idiopathic arthritis (JIA) when administered by an oral and maxillofacial surgeon without imaging guidance. Materials and Methods This was a retrospective study of children with JIA, seen at a single center, who were selected based on having received IACIs of the TMJ. All subjects received the intervention, which consisted of referral to a single oral and maxillofacial surgeon for TMJ IACI with 5 to 10 mg triamcinolone hexacetonide, under general anesthesia. Primary outcomes assessed in all subjects were the safety of the procedure and efficacy as determined by the change in maximal incisal opening (MIO). In addition, a subset of 31 subjects underwent repeat magnetic resonance imaging of the TMJ, permitting analysis of the change in the acute and chronic findings of arthritis in those patients. Results Sixty-three patients (68% female) received 137 IACIs. The mean age for diagnosis of JIA was 8.5 years, and the mean age at presentation for TMJ injections was 10 years. The injections were well tolerated: only 1 patient developed the steroid complication of hypopigmentation, and none developed degeneration or ankylosis. In terms of efficacy, the mean MIO increased from 40.8 ± 0.93 to 43.5 ± 0.90 mm ( P = .001); in addition, changing the unit of analysis to individual joints, in patients who underwent repeat magnetic resonance imaging examination, 51% of TMJs showed magnetic resonance imaging evidence of improvement of arthritic changes, of whom 18% had complete resolution of TMJ arthritis. Conclusions The results indicate that IACI of the TMJ can be safely performed by experienced oral and maxillofacial surgeons without a requirement for computed tomographic guidance. In addition, these results show that IACI may be effective in the management of TMJ arthritis, although further studies are required.
This study evaluates the effects of the overlap length and different adherend materials with different thicknesses on the mechanical performance of the bolted (BJ), adhesively bonded (ADJ) and hybrid ...joints (HJ) subjected to quasi-static axial tensile loading. The three different joints were fabricated and tested according to 36 different variances, including two kinds of adherend materials (AL6061 and Al7075 with different yield strength, tensile strength and ductility values), three adherend thicknesses (2 mm, 4 mm and 6 mm) and two overlap lengths (25 mm and 45 mm). Numerical models were implemented and developed using the commercial software Abaqus/Explicit. The adhesive layer (AF163-2K) was simulated by using cohesive interface elements with traction-separation response. Ductile/shear damage models were used to simulate the failure behavior of the adherends and the bolt material. To interpret the strength of various joints, failure behavior for each configuration is analyzed widely.
Background: As hand joints are non-weight bearing, the association between overweight and hand osteoarthritis (HOA) is critical to understanding how overweight may associate with osteoarthritis (OA) ...apart from axial load. Overweight might be associated with the occurrence of OA through other metabolic factors. Aim: To evaluate the role of overweight in HOA, cross-sectional data of a population-based study were used (⩾55 years, n = 3585). The role of diabetes, hypertension and total cholesterol:high-density lipoprotein (HDL)-cholesterol ratio on HOA, and whether they play an intermediate role in the association of overweight/HOA was investigated. Furthermore, the prevalence of HOA in the concurrent presence of overweight and other metabolic factors was evaluated. Results: Independently of other metabolic factors, overweight (body mass index (BMI) >27.4 kg/m2) showed a significant association with HOA (OR 1.4, 95% CI 1.2 to 1.7). The association between diabetes and HOA was only present in people aged 55–62 years (OR 1.9, 95% CI 1.0 to 3.8), but was absent in the total population or in other age groups. The association of hypertension with HOA was weak, and disappeared after adjustment for BMI. The total/HDL cholesterol ratio showed no significant association with HOA. The concurrent presence of overweight, diabetes and hypertension resulted in an even higher prevalence of HOA (OR 2.3, 95% CI 1.3 to 3.9) compared with subjects with none of these characteristics; this prevalence increased further in the younger age group (OR 3.2, 95% CI 1.1 to 8.8). Conclusion: No intermediate effect of metabolic factors on the association of overweight with HOA was found. An increase in the prevalence of HOA, however, seems to be present when overweight occurs together with hypertension and diabetes especially at a relatively young age.
The increased information provided by modern imaging has led to its more extensive use. Our aim was to develop evidence-based recommendations for the use of imaging in the clinical management of the ...most common arthropathy, osteoarthritis (OA). A task force (including rheumatologists, radiologists, methodologists, primary care doctors and patients) from nine countries defined 10 questions on the role of imaging in OA to support a systematic literature review (SLR). Joints of interest were the knee, hip, hand and foot; imaging modalities included conventional radiography (CR), MRI, ultrasonography, CT and nuclear medicine. PubMed and EMBASE were searched. The evidence was presented to the task force who subsequently developed the recommendations. The strength of agreement for each recommendation was assessed. 17 011 references were identified from which 390 studies were included in the SLR. Seven recommendations were produced, covering the lack of need for diagnostic imaging in patients with typical symptoms; the role of imaging in differential diagnosis; the lack of benefit in monitoring when no therapeutic modification is related, though consideration is required when unexpected clinical deterioration occurs; CR as the first-choice imaging modality; consideration of how to correctly acquire images and the role of imaging in guiding local injections. Recommendations for future research were also developed based on gaps in evidence, such as the use of imaging in identifying therapeutic targets, and demonstrating the added value of imaging. These evidence-based recommendations and related research agenda provide the basis for sensible use of imaging in routine clinical assessment of people with OA.
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