Rifampicin plays an important role in the treatment of staphylococcal prosthetic joint infection, as rifampicin-containing combinations have shown a high efficacy against Four rifampicin-resistant MRSA strains were used in this study. The MIC for all tested antibiotics was determined by Etest. Biofilms were formed on porous glass beads for 24h and exposed to Sb1 (107 PFU/mL) for 24h followed by exposure to antibiotic for 24h. Viability of bacteria after antimicrobial treatment was detected by beads sonication and plating of the sonication fluids. The minimum biofilm eradication concentration (MBEC) was defined as the lowest concentration of antibiotic required to kill all cells resulting in the appearance of no colony after plating of the sonication fluid (detection limit <20 CFU/mL). The synergistic effects were observed when Sb1 combined with antibiotics used at least 2 log-reduction lower concentrations.Aim
Method
Total Hip Arthroplasty (THA) devices are now increasingly subjected to a progressively greater range of kinematic and loading regimes from substantially younger and more active patients. In the interest of ensuring adequate THA solutions for all patient groups, THA polyethylene acetabular liner (PE Liner) wear representative of younger, heavier, and more active patients (referred to as HA in this study) warrants further understanding. Previous studies have investigated HA joint related morbidity [1]. Current or past rugby players are more likely to report osteoarthritis, osteoporosis, and joint replacement than a general population. This investigation aimed to provide a preliminary understanding of HA patient specific PE liner tribological performance during Standard Walking (SW) gait in comparison to IS0:14242-1:2014 standardized testing. Nine healthy male subjects volunteered for a gait lab-based study to collect kinematics and loading profiles. Owing to limitations in subject selection, five subjects wore a weighted jacket to increase Body Mass Index ≥30 (BMI). An induced increase in Bodyweight was capped (<30%BW) to avoid significantly effecting gait [3] (mean=11%BW). Six subjects identified as HA per BMI≥30, but with anthropometric ratios indicative of lower body fat as previously detailed by the author [2] (Waist-to-hip circumference ratio and waist circumference-to-height ratio). Three subjects identified as Normal (BMI<25). Instrumented force plate loading profiles were scaled (≈270%BW) in agreement with instrumented hip force data [4]. A previously verified THA (Pinnacle® Marathon® 36×56mm, DePuy Synthes) Finite Element Analysis wear model based on Archard's law and modified time hardening model [5] was used to predict geometrical changes due to wear and deformation, respectively (Figure 1). Subject dependent kinematic and loading conditions were sampled to generate, for both legs, 19 SW simulation runs using a central composite design of response surface method.Introduction
Materials and Methods
Persistent post-surgical pain affects 10%-80% of individuals after common operations, and is more common among patients with psychological factors such as depression, anxiety, or catastrophising. We conducted a systematic review and meta-analysis of randomised, controlled trials to evaluate the efficacy of perioperative psychotherapy for persistent postsurgical pain and physical impairment. We searched Medline, PsycINFO, CINAHL, and the Cochrane Central Registry of Controlled Trials to identify relevant RCTs, in any language, from inception of each database to September 1, 2016. Paired independent reviewers identified studies, extracted data, and assessed risk of bias. We pooled treatment effects of perioperative psychotherapy on similar outcomes across eligible trials, focusing on intention-to-treat analysis. We used random effects models to perform all meta-analyses. The Grading of Recommendations, Assessment, Development and Evaluation system was used to assess the quality of evidence. Our search found 15 trials (2220 patients) that were eligible for review. For both persistent post-surgical pain and physical impairment, perioperative education was ineffective, while active psychotherapy suggested a benefit (test of interaction P=0.01 for both outcomes). Moderate quality evidence showed that active perioperative psychotherapy (cognitive-behaviour therapy, relaxation therapy, or both) significantly reduced persistent post-surgical pain [weighted mean difference (WMD) −1.06 cm on a 10 cm visual analogue scale for pain, 95% confidence interval (CI) −1.56 to −0.55 cm, risk difference (RD) for achieving no more than mild pain (3 cm or less) 14%, 95% CI 8–21%] and physical impairment [WMD −9.87% on the 0–100% Oswestry Disability Index, 95% CI −13.42 to −6.32%, RD for achieving no more than mild disability (20% or less) 21%, 95% CI 13–29%]. Perioperative cognitive behavioural therapy and relaxation therapy are effective for reducing persistent pain and physical impairment after surgery. High quality evidence shows no significant effects of perioperative education or psychological support on persistent post-surgical pain or physical impairment compared with usual care. Future studies should explore targeted psychotherapy for surgical patients at higher risk for poor outcome.
Ciprofloxacin is recommended as anti-biofilm therapy for gram-negative periprosthetic joint infection. With ciprofloxacin monotherapy, resistance in gram-negative bacteria was observed. Therefore, we evaluated
Aim
Method
There is great potential for the use of computational tools within the design and test cycle for joint replacement devices. The increasing need for stratified treatments that are more relevant to specific patients, and implant testing under more realistic, less idealised, conditions, will progressively increase the pre-clinical experimental testing work load. If the outcomes of experimental tests can be predicted using low cost computational tools, then these tools can be embedded early in the design cycle, e.g. benchmarking various design concepts, optimising component geometrical features and virtually predicting factors affecting the implant performance. Rapid, predictive tools could also allow population-stratified scenario testing at an early design stage, resulting in devices which are better suited to a patient-specific approach to treatment. The aim of the current study was to demonstrate the ability of a rapid computational analysis tool to predict the behaviour of a total hip replacement (THR) device, specifically the risk of edge loading due to separation under experimental conditions. A series of models of a 36mm BIOLOX® Delta THR bearing (DePuy Synthes, Leeds, UK) were generated to match an experimental simulator study which included a mediolateral spring to cause lateral head separation due to a simulated mediolateral component misalignment of 4mm. A static, rigid, frictionless model was implemented in Python (PyEL, runtime: ∼1m), and results were compared against 1) a critically damped dynamic, rigid, FE model (runtime: ∼10h), 2) a critically damped dynamic, rigid, FE model with friction (µ = 0.05) (runtime: ∼10h), and 3) kinematic experimental test data from a hip simulator (ProSim EM13) under matching settings (runtime: ∼6h). Outputs recorded were the variation of mediolateral separation and force with time.INTRODUCTION
METHODS
Component positioning of an artificial hip joint plays a key role in durability of implant. Despite the fact that a number of numerical, experimental and clinical studies have been carried out to investigate the effects of cup inclination on polyethylene wear, steep inclination has been reported to be associated with both high and low volumetric wear. Moreover, how cup anteversion affects wear and its interaction with inclination are still unclear. To address these knowledge gaps, in this study wear and contact mechanics of a hip joint under various cup positioning has been investigated by using FEA (Finite Element Analysis). A Pinnacle® Marathon neutral liner 36×56mm was chosen to model the wear and creep over 3 million cycles (mc) based on the Archard's law and modified time hardening model in ANSYS, respectively. Central composite design of response surface method was used to generate 9 FEA runs, where the operative inclination angles varied from 35º, 45º to 55º and operative anteversion angles differed amongst 0º, 15º and 30º. The range of cup angles were chosen to be similar to the Lewinnek “golden” safe zone for dislocation. The gait cycle as specified in ISO 14242-1 was applied to the femoral head.INTRODUCTION
METHOD
Cyclooxygenase-2 (COX-2) enzyme is one of the major mediators during inflammation reactions, and COX-2 gene polymorphisms of rs20417 and rs689466 have been reported to be associated with several inflammatory diseases. However, potential links between the two polymorphisms and risk of developing post-traumatic osteomyelitis remain unclear. The present study aimed to investigate associations between the rs20417 and rs689466 polymorphisms and susceptibility to post-traumatic osteomyelitis in Chinese population. A total of 189 patients with definite diagnosis of post-traumatic osteomyelitis and 220 healthy controls were genotyped for rs20417 and rs689466 using the genotyping method*. Chi-square test was used to compare differences of genotype distributions as well as outcomes of five different genetic models between the two groups.Aim
Methods
To evaluate the clinical and radiographic outcomes of total knee arthroplasty using Vega® Knee System (B Braun-Aesculap, Tuttlingen, Germany) [Fig. 1] designed to allow high flexion by shortening the length of posterior condylar flange of femoral component after at least 2 year and to assess the occurrence of periprosthetic osteolysis and loosening at final follow-up. Of the patients who underwent total knee arthroplasty using Vega® Knee System between April 2011 and May 2013, 40 patients (46 knees) were enrolled. The mean age of the patients at the time of surgery was 72.3 years and the mean follow-up period was 29.4 months. Clinical parameters, including Knee Society Knee score, Knee Society Function score, maximal flexion and range of motion were evaluated. Relationship between postoperative maximal flexion and radiographic factors including the posterior tibial slope, the femoral condylar offset and the change of the posterior flange length of femoral condyle was analyzed. Also, the occurrence of periprosthetic osteolysis and loosening was assessed.Objectives
Materials and Methods
The purpose of this study was to compare the biomechanical effects of the trapezius transfer and the latissimus dorsi transfer in a cadaveric model of a massive posterosuperior rotator cuff tear. Eight cadaveric shoulders were tested at 0°, 30°, and 60° of abduction in the scapular plane with anatomically based muscle loading. Humeral rotational range of motion and the amount of humeral rotation due to muscle loading were measured. Glenohumeral kinematics and joint reaction forces were measured throughout the range of motion. After testing in the intact condition, the supraspinatus and infraspinatus were resected, simulating a massive rotator cuff tear. The lower trapezius transfer was then performed. Three muscle loading conditions for the trapezius (12N, 24N, 36N) were applied to simulate a lengthened graph as a result of excessive creep, a properly tensioned graph exerting a force proportional to the cross-sectional area of the inferior trapezius, and an over-constrained graph respectively. Next the latissimus dorsi transfer was performed and tested with one muscle loading condition 24N. A repeated-measures analysis of variance was used for statistical analysis.Background:
Methods:
Individuals with large Hill-Sachs lesions may be prone to failure and reoccurrence following standard arthroscopic Bankart repair. Here, the Remplissage procedure may promote shoulder stability through infraspinatus capsulo-tenodesis directly into the lesion. Little biomechanicaldata about the Remplissage procedure on glenohumeral kinematics, stability, and range of motion (ROM) currently exists. What are the biomechanical effects of Bankart and Remplissage repair for large Hill-Sachs lesions?Background:
Questions/purposes:
The verification of the alignment of the lower limb is critical for reconstructive surgery as well as trauma surgery in order to prevent osteoarthritis. The mechanical axis is a straight line defined by the center of the femoral head and the center of the ankle joint, ideally passing the knee joint in its center. Whereas the usual preoperative method to determine the mechanical axis of the lower limbs is still the long standing radiograph, common intra-operative methods are the use of an electrocautery cord or an X-ray grid consisting of wire lines underneath the patient. Both methods require the surgeon to bring the femoral head and the ankle joint exactly to overlay with a radiopaque line that passes through both points. The distance of the knee center from this line is defined as the mechanical axis deviation (MAD). In order to reduce the errors introduced by perspective projection effects, the joint centers must be placed in the center of the c-arm images, which definitely requires time, experience and additional radiation. We propose a computer aided X-ray stitching method that puts individual X-ray images into a panoramic image frame combining the Camera Augmented Mobile C-arm (CamC) system, which features a video camera with its optical center virtually coinciding with the origin of the X-rays, with an optical tracking marker pattern underneath the operating table. The camera image of the marker pattern is used to perform pose estimation of the C-arm, allowing the calculation of the x-ray source motion between the positions in which the individual X-rays were taken. By estimating the homography, the different X-rays can be registered into a panoramic frame, enabling perfect alignment and metric measurements. In order to reduce parallax effects that lead to axis and metric measurement errors, we applied a method requiring two constraints: The bone plane has to be roughly parallel to the planar marker pattern and the distance between the marker plane and the bone plane has to be estimated. In order to evaluate the method, we used a life-size synthetic skeleton leg. After tightening a straight wire between the centers of the hip and ankle joint, the knee joint was bent into a MAD of 55 mm, which was confirmed by measuring the distance between the knee center and the wire with a ruler. The leg phantom was then placed on a radiolucent operating table, parallel to the pattern plane 130 mm underneath. The operating table was moved through the C-arm while acquiring the three desired X-ray images. which were registered into a panoramic image frame. The centers of the femoral head, the ankle, and the knee were manually determined on the generated panoramic image by a surgeon. The mechanical axis was automatically displayed and the MAD was visualised in the image and computed as 55.23 mm. We presented a new solution to intra-operatively verify alignment of the lower extremity. When using the CamC system, only a marker pattern has to be used for tracking. No additional tracking devices and calibration procedures are needed. Furthermore, the presented method only requires three x-rays that cover the femoral head, the knee and the ankle and marking of the three spots. Due to the parallax correction, these spots do not have to be exactly in the center of the picture. For this reason, compared to using an X-ray grid or an electrocautery cord, our method allows the procedure to be much faster and reduces the number of x-ray images. However, for clinical evaluation, a patient study will be conducted in the future.
