Abstract

Each year more than 70 billion standard units of antibiotic are prescribed to treat bacterial infections worldwide. In addition, at least 63,000 tons of antibiotics are consumed by livestock for growth promotion and disease prevention. The result of this overuse of antibiotics is a spiraling increase in resistance. In the United States and Europe, antibiotic resistant bacteria are responsible for more than 4 million infections and approximately 50,000 deaths annually. In addition, bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) have increased in prevalence in hospitals over the last three decades. Such bacteria are particularly problematic in postoperative infections, exacerbating treatment through the development of biofilms, especially on medical implants which are virtually impossible to treat without removal and replacement of the device. This presentation will show how non-invasive preclinical imaging (optical, PET and CT) is being used to better understand the establishment and development of bacterial infections in vivo, and how best to treat them. In particular, data will be shown as to how preclinical imaging can be used to monitor bacterial infections on orthopaedic implants, and how this technology might be translated into the clinic

Introduction. Aged trauma patients with proximal femur fractures are prone to various complications. They may be associated with their comorbidities which also need to be adressed. These complications limit the patient”s postoperative health status and subsequently their activity and independency. As an attempt to improve the postoperative management of aged hip fracture patients a better understanding of the postoperative condition in these patients is necessary. Therefore, this meta-analysis is intended to provide an overview of postoperative complications in the elderly hip fracture patients and to improve the understanding of an adequate postoperative management. Material and method. Medline was used to screen for studies reporting on the complication rates of hip fracture patients > 65 years. The search criteria were: “proximal femur fracture, elderly, complication”. In addition to surgical studies, internal medicine and geriatric studies were also included. Randomized studies, retrospective studies as well as observation studies were included. Furthermore, reoperation rates as well as treatment-related complications were recorded. The 1-year mortality was calculated as outcome parameter. Results. Overall 54 studies were enrolled, published between 2011 and 2016. The mean age of the 9812 patients was 81 years (65–99 years). Follow-up was at least one year. The reoperation rate after osteosynthesis of pertrochanteric femur fractures was 8.7%. The reoperation rate was dependent on the type of fracture and the surgical method. Pneumonia (9,5%) and urinary tract infections (27%) were the most common postoperative infections. With 23%, delirium was one of the most common medical complications. The 1-year mortality rate was 18.7%. Conclusion. Orthogeriatric patients represent a complex patient population. Addressing the special needs of elderly patients reduces postoperative complications. Establishing comanagement or orthogeriatric wards can also be helpful to manage comorbidities and postoperative complications. It is important to not only choose the proper surgical procedure but to monitor orthogeriatric patients closely during their hospitalization

Summary Statement. Magnesium has a number of qualities suitable for bioresorbable metallic implants. However, high corrosion rate and formation of hydrogen gas can compromise its performance. Combining magnesium with calcium phosphate improves magnesium's biocompatibility by decreasing gas formation and increasing bone remodeling. Introduction. Clinical problems like risk of postoperative infection and increased incidence of pediatric trauma requiring surgical intervention raised the need for temporary orthopedic implants that would resorb after the bone healing is complete. This would decrease high costs associated with repeated surgeries, minimise recovery times, decrease the risk of postoperative infections, and thus promote higher quality of life to the patients. The specific requirement for orthopedic implants, aside from being bioresorbable, is the ability to bear high loads. Magnesium was suggested as a suitable material for these purposes because it is biocompatible; has excellent mechanical properties; is natural for human body, and seems to stimulate new bone formation. However, an important problem with magnesium is high corrosion rate with consistent hydrogen gas formation on contact with fluids. This in vivo study focuses on investigation of new magnesium-based implants specifically designed to minimise hydrogen gas formation. Methods. Four types of degradable magnesium-based materials were tested for biocompatibility in this study: Magnesium-Hydroxyapatite implants (Mg-HA); Magnesium-Calcium Phosphate Cement (Mg-CPC); alloy of 96% Magnesium and 4% Yttrium (W4); and 99.95% pure magnesium which was a control group. Biomaterials were operated into 33 male New Zealand white rabbits. The animals were sacrificed after 6 and 12 weeks after which the samples were embedded into Epon, paraffin and Technovit resin. The staining was done with TRAP, hematoxylin eosin and toluidine blue. Additionally, TEM and immunohistochemical analysis were performed. The data was analysed both qualitatively and quantitatively by Statistical Package for the Social Sciences (SPSS, v18, SPSS Inc, Chicago, IL). Results. Mg-CPC showed the best performance in this study. New bone formation was significantly more prevalent in Mg-CPC group while gas formation was significantly less comparing to the other materials. Mg-HA had the worst properties due to extremely fast degradation already at 6 weeks, the least amount of new bone formation, and the lowest amount of osteoclasts and multinucleated cells in the implantation site. Pure magnesium and W4 had similar properties: both were surrounded with corrosion layer, and the gas volumes were significantly higher in these two groups compared to other materials. Discussion/Conclusion. New bone was seen forming either in direct contact to implants or around the gas bubbles. The later can be interpreted as body's reaction to protect from gas spreading. Mg-HA's degradation rate was far too fast and this is unacceptable for orthopedic fractures which often require several months to heal and that experience much load. Pure magnesium and W4 although maintained their integrity, were surrounded by corrosion layer and gas bubbles that were bigger in diameter than in the other groups. These findings could compromise implant stability. Mg-CPC was the most biocompatible; it showed significantly higher amount of osteoclasts which is a first sign of bone remodeling. It had also significantly less gas production than other groups. These results show that magnesium's biocompatibility could be improved by combining it with other suitable materials, such as calcium phosphate

Late infection is the most frequent complications after hemiarthroplasty. Urinary tract infections are the only distant septic focus considered to be a risk factor in the literature. We retrospectively reviewed 460 patients with hip fracture treated by hemiarthroplasy over a period of one year. Preoperative positive urine dipsticks and urine analysis have been looked at as causes for delay of surgery in absence of clinical manifestations of urinary tract infection. 367 patients were operated within 24 hours. 78 patients were delayed more than 78 hours. Urinary tract infection had the least contribution as a cause of delay. 99 patients had preoperative urinary tract infection and 57 patients had postoperative wound infection. Of these with postoperative surgical site infection, 31 patients did not show any evidence of preoperative urinary tract infection, 23 patients had preoperative urinary tract infection, two had leg ulcer and one had chest infection. 13 patients had chronic urinary tract infection and five patients had the same causative organism in urine & wound. The most common organisms of urinary infection are E. Coli, mixed growth, Enteroccocus Faecalis, Pseudomonas and others. The most causative organism of the postoperative surgical site infection are Staph aureus including MRSA, mixed growth including Staph. Epidermidis, Enteroccocus Faecalis and others There is no direct significant correlation between preoperative urinary tract infection and surgical site infection. We recommend that preoperative urinary tract infection should be treated as a matter of urgency but it should not delay hip fracture surgery unless it is causing symptoms

Summary. Staphylococcus aureus isolates from Fracture fixation device related infections contained fewer isolates that form a strong biofilm in comparison with isolates from Prosthetic joint infections. Both orthopaedic implant related infection groups possessed fnbB and sdrE more frequently than the non-implant related infection groups. Introduction. One of the most common pathogen causing musculoskeletal infections is Staphylococcus aureus. The aim was to characterise S. aureus isolated from these infections and to look for differences between the isolates from orthopaedic implant related infections (OIRI) and those in non-implant related infections (NIRI). The OIRI are further differentiated in those associated with fracture fixation (FFI) devices and those found in prosthetic joint infections (PJI). Methods. Three-hundred and five S. aureus isolates were collected from different Swiss and French hospitals (FFI, n=112; PJI, n=105; NIRI, n=88). The cases of NIRI were composed of 27 osteomyelitis (OM), 23 diabetic foot infections (DFI), 27 soft tissue infections (STI) and 11 postoperative spinal infections (SI). Isolates were tested for their ability to form a biofilm. They were typed by agr (accessory gene regulator) group and genes coding for the 13 most relevant MSCRAMMs, Panton-Valentine leukocidin (PVL), PIA (polysaccharide intercellular adhesin), γ-haemolysin, the five most relevant Staphylococcal enterotoxins (SEA-SEE), exfoliative toxins A and B (ETA and ETB) and toxic shock protein (TST) were screened for by PCR. Results. The majority of the S. aureus isolates were methicillin susceptible (MSSA) with 83.4% for the OIRI and 93.2% for the NIRI. All isolates were able to produce a biofilm. A strong biofilm was produced in 13.8% of the OIRI isolates compared to 10.2% of the NIRI isolates. The difference between the isolates of the PJI versus the FFI was statistically significant (20% vs 8%; p=0.011). All four agr types were present in all groups. agrI predominated in the OIRI (42.4%) as well as in the NIRI (44.4%). Comparing OIRI with NIRI, agrII was present in a higher prevalence in OIRI (30.9% vs 14.8%) and agrIII in a lower incidence (21.2% vs 30.7%). Genes cna, clfA and bbp were exhibited predominantly by isolates from the NIRI, while the fnbB and the sdrE gene were more frequently observed among OIRI. Conclusions. Methicillin susceptible S. aureus (MSSA) was more prevalent than methicillin resistant S. aureus (MRSA) in this collection. Possible trends for the orthopaedic device associated infection groups FFI and PJI could be observed whereby isolates from PJI produced stronger biofilm than isolates from the FFI group. The agr type agrII, the fnbB gene and sdrE gene were more prevalent present in the OIRI compared to the NIRI. In contrast, agrIII, and the bbp gene were more prevalent in the NIRI than in the OIRI

Objectives

In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models.