The aim of this study was to perform the first population-based description of the epidemiological and health economic burden of fracture-related infection (FRI). This is a retrospective cohort study of operatively managed orthopaedic trauma patients from 1 January 2007 to 31 December 2016, performed in Queensland, Australia. Record linkage was used to develop a person-centric, population-based dataset incorporating routinely collected administrative, clinical, and health economic information. The FRI group consisted of patients with International Classification of Disease 10th Revision diagnosis codes for deep infection associated with an implanted device within two years following surgery, while all others were deemed not infected. Demographic and clinical variables, as well as healthcare utilization costs, were compared.Aims
Methods
The aim of this work was to compare the different techniques and the different fluid permeability of the tissue following each technique through assessing the flow of radiopaque contrast agent using μCT image analysis and 3D modelling. Donated human tali specimens (n=12) were prepared through creating a 10mm diameter chondral defect in three different regions of each talus. Each region then underwent one of three surgical techniques: 1) Fine wire drilling, 2) Nanofracture or 3) Microfracture, equidistant sites in each defect to ensure even distribution. Each region then had an addition of 0.1 ml radiopaque contrast agent (Omnipaque™ 300), imaged using a clinical μCT scanner (SCANCO Medical AG, 73.6 μm resolution). Each μCT scan was segmented using Slicer 3D software (The Slicer Community, 2023 3D Slicer (5.2.2)). The segmentation package was used to segment the bone and contrast agent regions in each different surgical site of each sample. Each defect site was created into a cylinder and the ratio of segmented pixels of contrast agent against bone.Abstract
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The aim of this study was to develop an in vitro GAG-depleted patella model and assess the biomechanical effects following treatment with a SAP:CS self-assembling hydrogel. Porcine patellae (4–6 month old) were harvested and subject to 0.1% (w/v) sodium dodecyl sulfate (SDS) washes to remove GAGs from the cartilage. Patellae were GAG depleted and then treated by injection with SAP (∼ 6 mM) and CS (10 mg) in Ringer's solution through a 30G needle. Native, GAG depleted and SAP:CS treated patellae were tested through static indentation testing, using 15g load, 5mm indenter over 1hr period. The degree of deformation of each group was assessed and compared (Mann-Whitney, p<0.05). Native, GAG depleted, sham (saline only) and SAP:CS treated paired patellae and femurs were additionally characterized tribologically through sequential wear testing when undergoing a walking gait profile (n=6 per group). The cartilage surfaces were assessed and compared (Mann-Whitney, p<0.05) using the ICRS scoring system, surface damage was illustrated through the application of Indian ink.Abstract
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While spinal fusion is known to be associated with adjacent disc degeneration, little is known on the role of the facet joints in the process, and whether their altered biomechanics following fusion plays a role in further spinal degeneration. This work aimed to develop a model and method to sequentially measure the effects of spinal fusion on lumbar facet joints through synchronisation of both motion analysis, pressure mapping and mechanical analysis. Parallel measurements of mature ovine lumbar facet joints (∼8yr old, n=3) were carried out using synchronised load and displacement measurements, motion capture during loading and pressure mapping of the joint spaces during loading. Functional units were prepared and cemented in PMMA endcaps. Displacement-controlled compression measurements were carried out using a materials testing machine (3365, Instron, USA) at 1 mm/min up to 950 N with the samples in a neutral position, while motion capture of the facet joints during compression was carried out using orthogonal HD webcams (Logitech, Switzerland) to measure the displacement of key facet joint features. The pressure mapping of load transfer during displacement was carried out using a flexible pressure sensor (6900 series, Tekscan, USA). Each sample was imaged at an isotropic resolution of 82 microns using a μCT scanner (XtremeCT, Scanco, Switzerland) to quantify the curvature within the facet joints.Abstract
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Several options to standardize the definition of periprosthetic joint infection (PJI) have been created including the 2013 Musculoskeletal Infection Society (MSIS), 2018 Intentional Consensus Meeting (ICM), and the 2019 proposed European Bone and Joint Infection Society (EBJIS) criteria. Synovial fluid biomarkers have been investigated in an effort to simplify and improve the diagnosis of PJI. The aim of this study was to test the sensitivity, specificity, positive, and negative predicted values (PPV and NPV, respectively) of a calprotectin point of care (POC) test for diagnosing PJI in revision total knee arthroplasty (TKA) patients comparing different sets of criteria (2013 MSIS, 2018 ICM, and 2019 EBJIS criteria) used to define patients as with or without infection. From October 2018 to January 2020 and under IRB approval 123 intraoperative samples of synovial fluid were prospectively collected at two academic hospitals in the same institution from revision TKA patients. All patients underwent standard clinical and laboratory evaluation for PJI at our institution, allowing for categorization using the 3 criteria. Patients were adjudicated by 2 blinded and independent reviewers for the 3 sets of criteria. The 3 criteria agreed 91.8% of the time. Four likely cases by the 2019 proposed EBJIS were considered unlikely and 1 inconclusive case by the 2018 ICM was considered not infected for the purposes of analysis. Calprotectin POC testing followed manufacturer's instructions using a threshold of >50 mg/L to indicate PJI. Sensitivities, specificities, PPV, NPV, and areas under the curve (AUC) were calculated for the 3 sets of criteria.Aim
Method
Despite several synovial fluid biomarkers for diagnosis of periprosthetic joint infection (PJI) have being investigated, point-of-care (POC) tests using these biomarkers are not widely available. Synovial calprotectin has recently been reported to effectively exclude diagnosis of PJI and a novel lateral flow POC test using it has shown potential to be effective. Thus, the aims of this study were to 1) validate calprotectin POC with enzyme linked immunosorbet assay (ELISA) 2) at 2 separate thresholds for PJI diagnosis in total knee arthroplasty (TKA) patients using the 2013 Musculoskeletal Infection Society (MSIS) PJI diagnosis criteria as the gold standard. Intraoperative synovial fluid samples were prospectively collected from 123 patients who underwent revision TKAs (rTKA) at two academic hospitals within the same healthcare system from October 2018 to January 2020. The study was conducted under IRB approval. Included patients followed the hospital standard for their PJI diagnostic work-up. Data collection included demographic, clinical, and laboratory data in compliance with MSIS criteria. Synovial fluid samples were analysed by calprotectin POC and ELISA tests in accordance with manufacturer's instructions. Patients were categorized as septic or aseptic using MSIS criteria by two independent reviewers blinded to calprotectin assay results. The calprotectin POC and ELISA test performance characteristics were calculated with sensitivities, specificities, positive, and negative predicted values (PPV and NPV, respectively) and areas under the curve (AUC) for 2 different PJI diagnosis scenarios: (1) a threshold of >50 mg/L and (2) a threshold of >14 mg/L.Aim
Method
Thresholds for operative eligibility based on body mass index (BMI) alone may restrict patient access to the benefits of arthroplasty. The purpose of this study was to evaluate the relationship between BMI and improvements in patient-reported outcome measures (PROMs), and to determine how many patients would have been denied improvements in PROMs if BMI cut-offs were to be implemented. A prospective cohort of 3,449 primary total hip arthroplasties (THAs) performed between 2015 and 2018 were analyzed. The following one-year PROMs were evaluated: hip injury and osteoarthritis outcome score (HOOS) pain, HOOS Physical Function Shortform (PS), University of California, Los Angeles (UCLA) activity, Veterans Rand-12 Physical Component Score (VR-12 PCS), and VR-12 Mental Component Score (VR-12 MCS). Positive predictive values for failure to improve and the number of patients denied surgery in order to avoid a failed improvement were calculated for each PROM at different BMI cut-offs.Aims
Methods
Proper positioning of the acetabular component is critical for prevention of dislocation and excessive wear for total hip arthroplasty (THA) and hip resurfacing. Consideration of preoperative pelvic tilt (PT) may aid in acetabular component placement. The purpose of this study was to investigate how PT changes after hip resurfacing, via pre and post-operative radiographic analysis of anterior pelvic plane (APP), and whether radiographic analysis of the APP is a reproducible method for evaluating PT in resurfaced hips. A consecutive group of 228 patients from a single surgeon who had hip resurfacing were evaluated. We obtained x-rays from an institutional database for these patients who had their surgeries between January 1st, 2014 to December 31st, 2016. Pelvic tilt (PT) was measured by two observers before and after resurfacing utilizing a standardized radiographic technique. Correlation coefficients were calculated for PT measurements between observers, and pre- and post-surgery.Background
Methods
Intervertebral disc (IVD) degeneration is one of the major causes of back pain. A number of emerging treatments for the condition have failed during clinical trial due to the lack of robust biomechanical testing during product development. The aim of this work was to develop improved in-vitro testing methods to enable new therapeutic approaches to be examined pre-clinically. It forms part of a wider programme of research to develop a minimally invasive nucleus augmentation procedure using self-assembling hydrogels. Previous static testing on extracted IVDs have shown large inter-specimen variation in the measured stiffness when specimen hydration and fluid flow were not well controlled. In this work, a method of normalising the hydration state of IVDs prior-to and during compressive testing was developed. Excised adult bovine IVDs underwent water-pik treatment and a 24-hour agitated bath in monosodium citrate solution to maximise fluid mobility. Specimens were submerged in a saline bath and held under constant pressure for 24 hours, after which the rate of change of displacement was low. Specimens were then cyclically loaded, from which the normalised specimen stiffness was determined. A degenerate disc model was developed with the use of enzymatic degeneration, allowing specimens to be tested sequentially in a healthy, degenerate, and then treated state. Self-assembling peptide-GAG hydrogels were tested using the developed method and the effect of treatment on stiffness and disc height were assessed. Compared to previous static tests, the improved method reduced the variation in the normalised specimen stiffness. In addition, statistically significant differences were seen before and after enzymatic degradation to simulate degeneration, thus providing controls against which to evaluate treatments. The augmentation of the nucleus with the hydrogel intervention reduces the stiffness of the degenerate disc towards that of the healthy disc. This method is now being used to further investigate nucleus augmentation devices.
Introduction: The clinically significant threshold above which a scoliotic curve could be abnormal remains arbitrary. Data on normal adolescent and adult back shape are scarce. However clinical decision making based on subjective, visual criteria influences management. We aimed to produce measurable values of normal back shape, against which deformity could be defined. Method: 48 volunteering young adults perceiving themselves as “normal” participated in the study. All have been cleared previously by school screening. Their age (18–28 years old) precluded curve deterioration, but was close enough to adolescent measurements at the end of growth. Back shape was assessed with the ISIS system. Results: A minority of 8% showed no curve, with 54% a single curve and the rest a double one. Right spinal asymmetry (77%) was more frequent than the left (52%). Mean values and 95% confidence intervals were 16.1° (14.0°–18.2°) for upper spinal asymmetry, 13.4° (10.1°–16.6°) for lower lateral asymmetry, 24.9 mm (20.6 mm–29.2 mm) for thoracic kyphosis and 14.9 mm (12.5 mm–17.2 mm) for lumbar lordosis. Increasing upper lateral asymmetry correlated with decreasing thoracic kyphosis (p<
0.01). Maximum skin surface angle correlated positively with only upper lateral asymmetry (p<
0.001). Conclusion: Normal spines comprise of lateral asymmetries, where straight is the exception more than the rule. Scoliosis seems to be an exacerbation of this lateral asymmetry beyond 18° for the upper and 16° for the lower spinal asymmetry. Hypokyphosis is related to upper lateral spinal asymmetry. Skin surface angle is a very good indicator of only the upper lateral asymmetry.
