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Background: The treatment for deep surgical site infection (SSI) following primary total hip arthroplasty (THA) varies internationally and it is at present unclear which treatment approaches are used in Australia. The aim of this study is to identify current treatment approaches in Queensland, Australia, show success rates and quantify the costs of different treatments. Methods: Data for patients undergoing primary THA and treatment for infection between January 2006 and December 2009 in Queensland hospitals were extracted from routinely used hospital databases. Records were linked with pathology information to confirm positive organisms. Diagnosis and treatment of infection was determined using ICD-10-AM and ACHI codes, respectively. Treatment costs were estimated based on AR-DRG cost accounting codes assigned to each patient hospital episode. Results: A total of n=114 patients with deep surgical site infection were identified. The majority of patients (74%) were first treated with debridement, antibiotics and implant retention (DAIR), which was successful in eradicating the infection in 60.3% of patients with an average cost of $13,187. The remaining first treatments were 1-stage revision, successful in 89.7% with average costs of $27,006, and 2-stage revisions, successful in 92.9% of cases with average costs of $42,772. Multiple treatments following 'failed DAIR' cost on average $29,560, for failed 1-stage revision were $24,357, for failed 2-stage revision were $70,381 and were $23,805 for excision arthroplasty. Conclusions: As treatment costs in Australia are high primary prevention is important and the economics of competing treatment choices should be carefully considered. These currently vary greatly across international settings. [ABSTRACT FROM AUTHOR]

Background: Evidence has strongly indicated that surface-active phospholipid (SAPL), or surfactant, lines the surface of cartilage and serves as a lubricating agent. Previous clinical study showed that a saturated phosphatidylcholine (SPC), dipalmitoyl-phosphatidylcholine (DPPC), was effective in the treatment of osteoarthritis, however recent studies suggested that the dominant SAPL species at some sites outside the lung are not SPC, rather, are unsaturated phosphatidylcholine (USPC). Some of these USPC have been proven to be good boundary lubricants by our previous study, implicating their possible important physiological roles in joint if their existence can be confirmed. So far, no study has been conducted to identify the whole molecule species of different phosphatidylcholine (PC) classes on the surface of cartilage. In this study we identified the dominant PC molecule species on the surface of cartilage. We also confirmed that some of these PC species possess a property of semipermeability. Methods: HPLC was used to analyse the PC profile of bovine cartilage samples and comparisons of DPPC and USPC were carried out through semipermeability tests. Results: It was confirmed that USPC are the dominant SAPL species on the surface of cartilage. In particular, they are Dilinoleoyl-phosphatidylcholine (DLPC), Palmitoyl-linoleoylphosphatidylcholine, (PLPC), Palmitoyl-oleoyl-phosphatidylcholine (POPC) and Stearoyl-linoleoylphosphatidylcholine (SLPC). The relative content of DPPC (a SPC) was only 8%. Two USPC, PLPC and POPC, were capable of generating osmotic pressure that is equivalent to that by DPPC. Conclusion: The results from the current study confirm vigorously that USPC is the endogenous species inside the joint as against DPPC thereby confirming once again that USPC, and not SPC, characterizes the PC species distribution at non-lung sites of the body. USPC not only has better anti-friction and lubrication properties than DPPC, they also possess a level of semipermeability that is equivalent to DPPC. We therefore hypothesize that USPC can constitute a possible addition or alternative to the current commercially available viscosupplementation products for the prevention and treatment of osteoarthritis in the future. [ABSTRACT FROM AUTHOR]

The treatment of critical-size bone defects with irregular shapes remains a major challenge in the field of orthopedics. Bone implants with adaptability to complex morphological bone defects, bone-adhesive properties, and potent osteogenic capacity are necessary. Here, a shape-adaptive, highly bone-adhesive, and ultrasound-powered injectable nanocomposite hydrogel is developed via dynamic covalent crosslinking of amine-modified piezoelectric nanoparticles and biopolymer hydrogel networks for electrically accelerated bone healing. Depending on the inorganic-organic interaction between the amino-modified piezoelectric nanoparticles and the bio-adhesive hydrogel network, the bone adhesive strength of the prepared hydrogel exhibited an approximately 3-fold increase. In response to ultrasound radiation, the nanocomposite hydrogel could generate a controllable electrical output (-41.16 to 61.82 mV) to enhance the osteogenic effect in vitro and in vivo significantly. Rat critical-size calvarial defect repair validates accelerated bone healing. In addition, bioinformatics analysis reveals that the ultrasound-responsive nanocomposite hydrogel enhanced the osteogenic differentiation of bone mesenchymal stem cells by increasing calcium ion influx and up-regulating the PI3K/AKT and MEK/ERK signaling pathways. Overall, the present work reveals a novel wireless ultrasound-powered bone-adhesive nanocomposite hydrogel that broadens the therapeutic horizons for irregular bone defects. [ABSTRACT FROM AUTHOR]

Background: The treatment for deep surgical site infection (SSI) following primary total hip arthroplasty (THA) varies internationally and it is at present unclear which treatment approaches are used in Australia. The aim of this study is to identify current treatment approaches in Queensland, Australia, show success rates and quantify the costs of different treatments.Methods: Data for patients undergoing primary THA and treatment for infection between January 2006 and December 2009 in Queensland hospitals were extracted from routinely used hospital databases. Records were linked with pathology information to confirm positive organisms. Diagnosis and treatment of infection was determined using ICD-10-AM and ACHI codes, respectively. Treatment costs were estimated based on AR-DRG cost accounting codes assigned to each patient hospital episode.Results: A total of n=114 patients with deep surgical site infection were identified. The majority of patients (74%) were first treated with debridement, antibiotics and implant retention (DAIR), which was successful in eradicating the infection in 60.3% of patients with an average cost of $13,187. The remaining first treatments were 1-stage revision, successful in 89.7% with average costs of $27,006, and 2-stage revisions, successful in 92.9% of cases with average costs of $42,772. Multiple treatments following 'failed DAIR' cost on average $29,560, for failed 1-stage revision were $24,357, for failed 2-stage revision were $70,381 and were $23,805 for excision arthroplasty.Conclusions: As treatment costs in Australia are high primary prevention is important and the economics of competing treatment choices should be carefully considered. These currently vary greatly across international settings. [ABSTRACT FROM AUTHOR]

Background: It is well-known that both macrophages and osteocytes are critical regulators of osteogenesis and osteoclastogenesis, yet there is limited understanding of the macrophage-osteocyte interaction, and how their crosstalk could affect bone homeostasis and mineralization. This research therefore aims to investigate the effects of macrophage polarization on osteocyte maturation and mineralization process. Methods: A macrophage-derived conditioned medium based osteocyte culture was set up to investigate the impact of macrophages on osteocyte maturation and terminal mineralization. Surgically induced osteoarthritis (OA) rat model was used to further investigate the macrophage-osteocyte interaction in inflammatory bone remodeling, as well as the involvement of the Notch signaling pathway in the mineralization process. Results: Our results identified that osteocytes were confined in an immature stage after the M1 macrophage stimulation, showing a more rounded morphology, higher expression of early osteocyte marker E11, and significantly lower expression of mature osteocyte marker DMP1. Immature osteocytes were also found in inflammatory bone remodeling areas, showing altered morphology and mineralized structures similar to those observed under the stimulation of M1 macrophages in vitro, suggesting that M1 macrophages negatively affect osteocyte maturation, leading to abnormal mineralization. The Notch signaling pathway was found to be down regulated in M1 macrophage-stimulated osteocytes as well as osteocytes in inflammatory bone. Overexpression of the Notch signaling pathway in osteocytes showed a significant circumvention on the negative effects from M1 macrophage. Conclusion: Taken together, our findings provide valuable insights into the mechanisms involved in abnormal bone mineralization under inflammatory conditions. [ABSTRACT FROM AUTHOR]

Should mechanical VTE prophylaxis be indicated in all Asian patients who are contraindica... Recommendation Yes, mechanical VTE prophylaxis is the most appropriate VTE prevention in Asian patients who are contraindicated for pharmacological prophylaxis. This study, on 454 patients who underwent hip fracture surgery with mechanical prophylaxis in all cases, showed an overall DVT incidence of 6.4% (29 patients) and a PE incidence of 1.3% (6 patients) [[24]]. Should a mechanical device for VTE prophylaxis be routinely applied in Asian patients unde... Recommendation Yes, a mechanical device for VTE prophylaxis should routinely be applied in all Asian patients undergoing knee and hip arthroplasty and hip fracture surgery. The subgroup analysis found that 19 (0.8%) proximal DVTs and 83 (3.8%) distal DVTs developed in the patients without chemoprophylaxis, and 4 (0.7%) proximal DVTs and 28 (5.2%) distal DVTs developed in the patients with chemoprophylaxis [[18]]. [Extracted from the article]

Background: Although articular cartilage is the primary tissues affected by osteoarthritis (OA), the underlying subchondral bone also undergoes noticeable changes. Despite the growing body of research into the biophysical and mechanical properties of OA bone there are few studies that have analysed the structure of the subchondral sclerosis at the nanoscale. In this study, the composition and nano-structural changes of human osteoarthritis (OA) subchondral bone were investigated to better understand the site-specific changes.Methods: OA bone samples were collected from patients undergoing total knee replacement surgery and graded according to disease severity (grade I: mild OA; grade IV: severe OA). Transmission electron microscopy (TEM), Electron Diffraction, and Elemental Analysis techniques were used to explore the cross-banding pattern, nature of mineral phase and orientation of the crystal lattice. Subchondral bone nano-hydroxyapatite powders were prepared and characterised using high resolution transmission electron microscopy (HR-TEM) and fourier transform infrared spectroscopy (FTIR). Subchondal bone mechanical properties were investigated using a nano-indentation method.Results: In grade I subchondral bone samples, a regular periodic fibril banding pattern was observed and the c-axis orientation of the apatite crystals was parallel to the long axis of the fibrils. By contrast, in grade IV OA bone samples, the bulk of fibrils formed a random and undulated arrangement accompanied by a circular oriented pattern of apatite crystals. Fibrils in grade IV bone showed non-hierarchical intra-fibrillar mineralization and higher calcium (Ca) to phosphorous (P) (Ca/P) ratios. Grade IV OA bone showed higher crystallinity of the mineral content, increased modulus and hardness compared with grade I OA bone.Conclusions: The findings from this study suggest that OA subchondral sclerotic bone has an altered mineralization process which results in nano-structural changes of apatite crystals that is likely to account for the compromised mechanical properties of OA subchondral bones. [ABSTRACT FROM AUTHOR]

Background: There is little scientific evidence to support the usual practice of providing outpatient rehabilitation to patients undergoing total knee replacement surgery (TKR) immediately after discharge from the orthopaedic ward. It is hypothesised that the lack of clinical benefit is due to the low exercise intensity tolerated at this time, with patients still recovering from the effects of major orthopaedic surgery. The aim of the proposed clinical trial is to investigate the clinical and cost effectiveness of a novel rehabilitation strategy, consisting of an initial home exercise programme followed, approximately six weeks later, by higher intensity outpatient exercise classes.Methods/design: In this multicentre randomised controlled trial, 600 patients undergoing primary TKR will be recruited at the orthopaedic pre-admission clinic of 10 large public and private hospitals in Australia. There will be no change to the medical or rehabilitative care usually provided while the participant is admitted to the orthopaedic ward. After TKR, but prior to discharge from the orthopaedic ward, participants will be randomised to either the novel rehabilitation strategy or usual rehabilitative care as provided by the hospital or recommended by the orthopaedic surgeon. Outcomes assessments will be conducted at baseline (pre-admission clinic) and at 6 weeks, 6 months and 12 months following randomisation. The primary outcomes will be self-reported knee pain and physical function. Secondary outcomes include quality of life and objective measures of physical performance. Health economic data (health sector and community service utilisation, loss of productivity) will be recorded prospectively by participants in a patient diary. This patient cohort will also be followed-up annually for five years for knee pain, physical function and the need or actual incidence of further joint replacement surgery.Discussion: The results of this pragmatic clinical trial can be directly implemented into clinical practice. If beneficial, the novel rehabilitation strategy of utilising outpatient exercise classes during a later rehabilitation phase would provide a feasible and potentially cost-effective intervention to optimise the physical well-being of the large number of people undergoing TKR.Trial Registration: ACTRN12609000054213. [ABSTRACT FROM AUTHOR]