The aim of this study was to evaluate whether
coating titanium discs with selenium in the form of sodium selenite decreased
bacterial adhesion of In order to evaluate bacterial adhesion, sterile titanium discs
were coated with increasing concentrations of selenium and incubated
with bacterial solutions of The tested Selenium coating is a promising method to reduce bacterial attachment
on prosthetic material. Cite this article:
The biological significance of cobalt-chromium wear particles from metal-on-metal hip replacements may be different to the effects of the constituent metal ions in solution. Bacteria may be able to discriminate between particulate and ionic forms of these metals because of a transmembrane nickel/cobalt-permease. It is not known whether wear particles are bacteriocidal. We compared the doubling time of coagulase negative staphylococcus, Doubling time halved in metal-on-metal (p = 0.003) and metal-on-polyethylene (p = 0.131) particulate debris compared with the control. Bacterial nickel/cobalt-transporters allow metal ions but not wear particles to cross bacterial membranes. This may be useful for testing the biological characteristics of different wear debris. This experiment also shows that metal-on-metal hip wear debris is not bacteriocidal.
Periprosthetic joint infection (PJI) is one of
the most feared and challenging complications following total knee arthroplasty.
We provide a detailed description of our current understanding regarding
the management of PJI of the knee, including diagnostic aids,
pre-operative planning, surgical treatment, and outcome. Cite this article:
Nanotechnology is the study, production and controlled
manipulation of materials with a grain size <
100 nm. At this
level, the laws of classical mechanics fall away and those of quantum
mechanics take over, resulting in unique behaviour of matter in
terms of melting point, conductivity and reactivity. Additionally,
and likely more significant, as grain size decreases, the ratio
of surface area to volume drastically increases, allowing for greater interaction
between implants and the surrounding cellular environment. This
favourable increase in surface area plays an important role in mesenchymal
cell differentiation and ultimately bone–implant interactions. Basic science and translational research have revealed important
potential applications for nanotechnology in orthopaedic surgery,
particularly with regard to improving the interaction between implants
and host bone. Nanophase materials more closely match the architecture
of native trabecular bone, thereby greatly improving the osseo-integration
of orthopaedic implants. Nanophase-coated prostheses can also reduce
bacterial adhesion more than conventionally surfaced prostheses.
Nanophase selenium has shown great promise when used for tumour
reconstructions, as has nanophase silver in the management of traumatic
wounds. Nanophase silver may significantly improve healing of peripheral
nerve injuries, and nanophase gold has powerful anti-inflammatory
effects on tendon inflammation. Considerable advances must be made in our understanding of the
potential health risks of production, implantation and wear patterns
of nanophase devices before they are approved for clinical use.
Their potential, however, is considerable, and is likely to benefit
us all in the future. Cite this article:
Based on the first implementation of mixing antibiotics
into bone cement in the 1970s, the Endo-Klinik has used one stage
exchange for prosthetic joint infection (PJI) in over 85% of cases.
Looking carefully at current literature and guidelines for PJI treatment,
there is no clear evidence that a two stage procedure has a higher
success rate than a one-stage approach. A cemented one-stage exchange
potentially offers certain advantages, mainly based on the need
for only one operative procedure, reduced antibiotics and hospitalisation time.
In order to fulfill a one-stage approach, there are obligatory pre-,
peri- and post-operative details that need to be meticulously respected,
and are described in detail. Essential pre-operative diagnostic
testing is based on the joint aspiration with an exact identification
of any bacteria. The presence of a positive bacterial culture and
respective antibiogram are essential, to specify the antibiotics
to be loaded to the bone cement, which allows a high local antibiotic
elution directly at the surgical side. A specific antibiotic treatment
plan is generated by a microbiologist. The surgical success relies
on the complete removal of all pre-existing hardware, including
cement and restrictors and an aggressive and complete debridement
of any infected soft tissues and bone material. Post-operative systemic
antibiotic administration is usually completed after only ten to
14 days. Cite this article:
The aims of this study were to evaluate the incidence
of local argyria in patients with silver-coated megaprostheses and
to identify a possible association between argyria and elevated
levels of silver both locally and in the blood. Between 2004 and
2011, 32 megaprostheses with silver coatings were implanted in 20
female and 12 male patients following revision arthroplasty for
infection or resection of a malignant tumour, and the levels of
silver locally in drains and seromas and in the blood were determined.
The mean age of the patients was 46 years (10 to 81); one patient
died in the immediate post-operative period and was excluded. Seven patients (23%) developed local argyria after a median of
25.7 months (interquartile range 2 to 44.5). Patients with and without
local argyria had comparable levels of silver in the blood and aspiration
fluids. The length of the implant did not influence the development
of local argyria. Patients with clinical evidence of local argyria
had no neurological symptoms and no evidence of renal or hepatic
failure. Thus, we conclude that the short-term surveillance of blood
silver levels in these patients is not required. Cite this article:
The April 2013 Research Roundup360 looks at: when the ‘residency cake’ is done; steroids, stem cells and tendons; what exactly is osteoarthritis; platelet-rich plasma; CRPS; d-Dimer for DVT; reducing bacterial adhesion; and fin or limb?
The June 2012 Research Roundup360 looks at: platelet-rich plasma; ageing, bone and mesenchymal stem cells; cytokines and the herniated intervertebral disc; ulcerative colitis, Crohn’s disease and anti-inflammatories; the effect of NSAIDs on bone healing; osteoporosis of the fractured hip; herbal medicine and recovery after acute muscle injury; and ultrasound and the time to fracture union.
Coloured bone cements have been introduced to
make the removal of cement debris easier at the time of primary and
revision joint replacement. We evaluated the physical, mechanical
and pharmacological effects of adding methylene blue to bone cement
with or without antibiotics (gentamicin, vancomycin or both). The
addition of methylene blue to plain cement significantly decreased
its mean setting time (570 seconds (
Aspiration arthrography using an iodinated contrast medium is a useful tool for the investigation of septic or aseptic loosening of arthroplasties and of septic arthritis. Previously, the contrast media have been thought to cause false negative results in cultures when present in aspirated samples of synovial fluid, probably because free iodine is bactericidal, but reports have been inconclusive. We examined the influence of the older, high osmolar contrast agents and the low osmolar media used currently on the growth of ten different micro-organisms capable of causing deep infection around a prosthesis. Five media were tested, using a disc diffusion technique and a time-killing curve method in which high and low inocula of micro-organisms were incubated in undiluted media. The only bactericidal effects were found with low inocula of The low and iso-osmolar iodinated contrast media used currently do not impede culture. Future study must assess other causes of false negative cultures of synovial fluid and new developments in enhancing microbial recovery from aspirated samples.
We have developed an animal model to examine the formation of heterotopic ossification using standardised muscular damage and implantation of a beta-tricalcium phosphate block into a hip capsulotomy wound in Wistar rats. The aim was to investigate how cells originating from drilled femoral canals and damaged muscles influence the formation of heterotopic bone. The femoral canal was either drilled or left untouched and a tricalcium phosphate block, immersed either in saline or a rhBMP-2 solution, was implanted. These implants were removed at three and 21 days after the operation and examined histologically, histomorphometrically and immunohistochemically. Bone formation was seen in all implants in rhBMP-2-immersed, whereas in those immersed in saline the process was minimal, irrespective of drilling of the femoral canals. Bone mineralisation was somewhat greater in the absence of drilling with a mean mineralised volume to mean total volume of 18.2% ( Our findings suggest that osteoinductive signalling is an early event in the formation of ectopic bone. If applicable to man the results indicate that careful tissue handling is more important than the prevention of the dissemination of bone cells in order to avoid heterotopic ossification.
Platelet-leucocyte gel (PLG), a new biotechnological blood product, has hitherto been used primarily to treat chronic ulcers and to promote soft-tissue and bone regeneration in a wide range of medical fields. In this study, the antimicrobial efficacy of PLG against Staphylococcus aureus (ATCC 25923) was investigated in a rabbit model of osteomyelitis. Autologous PLG was injected into the tibial canal after inoculation with Staph. aureus. The prophylactic efficacy of PLG was evaluated by microbiological, radiological and histological examination. Animal groups included a treatment group that received systemic cefazolin and a control group that received no treatment. Treatment with PLG or cefazolin significantly reduced radiological and histological severity scores compared to the control group. This result was confirmed by a significant reduction in the infection rate and the number of viable bacteria. Although not comparable to cefazolin, PLG exhibited antimicrobial efficacy in vivo and therefore represents a novel strategy to prevent bone infection in humans.
Non-tuberculous mycobacterial infections pose a significant diagnostic and therapeutic challenge. We report two cases of such infection of the spine in HIV-negative patients who presented with deformity and neurological deficit. The histopathological features in both specimens were diagnostic of tuberculosis. The isolates were identified as
Methicillin-resistant Staphylococcus aureus (MRSA) has become a ubiquitous bacterium in both the hospital and community setting. There are two major subclassifications of MRSA, community-acquired and healthcare-acquired, each with differing pathogenicity and management. MRSA is increasingly responsible for infections in otherwise healthy, active adults. Local outbreaks affect both professional and amateur athletes and there is increasing public awareness of the issue. Health-acquired MRSA has major cost and outcome implications for patients and hospitals. The increasing prevalence and severity of MRSA means that the orthopaedic community should have a basic knowledge of the bacterium, its presentation and options for treatment. This paper examines the evolution of MRSA, analyses the spectrum of diseases produced by this bacterium and presents current prevention and treatment strategies for orthopaedic infections from MRSA.
Bone cements produced by different manufacturers vary in their mechanical properties and antibiotic elution characteristics. Small changes in the formulation of a bone cement, which may not be apparent to surgeons, can also affect these properties. The supplier of Palacos bone cement with added gentamicin changed in 2005. We carried out a study to examine the mechanical characteristics and antibiotic elution of Schering-Plough Palacos, Heraeus Palacos and Depuy CMW Smartset bone cements. Both Heraeus Palacos and Smartset bone cements performed significantly better than Schering-Plough Palacos in terms of mechanical characteristics, with and without additional vancomycin (p <
0.001). All cements show a deterioration in flexural strength with increasing addition of vancomycin, albeit staying above ISO minimum levels. Both Heraeus Palacos and Smartset elute significantly more gentamicin cumulatively than Schering-Plough Palacos. Smartset elutes significantly more vancomycin cumulatively than Heraeus Palacos. The improved antibiotic elution characteristics of Smartset and Heraeus Palacos are not associated with a deterioration in mechanical properties. Although marketed as the ‘original’ Palacos, Heraeus Palacos has significantly altered mechanical and antibiotic elution characteristics compared with the most commonly-used previous version.
Allograft bone is widely used in orthopaedic surgery, but peri-operative infection of the graft remains a common and disastrous complication. The efficacy of systemic prophylactic antibiotics is unproven, and since the graft is avascular it is likely that levels of antibiotic in the graft are low. Using an electrical potential to accelerate diffusion of antibiotics into allograft bone, high levels were achieved in specimens of both sheep and human allograft. In human bone these ranged from 187.1 mg/kg in endosteal ( Structural allograft can be supplemented directly with antibiotics using iontophoresis. The technique is simple and inexpensive and offers a potential means of reducing the rate of peri-operative infection in allograft surgery. Iontophoresis into allograft bone may also be applicable to other therapeutic compounds.
Iontophoresis is a novel technique which may be used to facilitate the movement of antibiotics into the substance of bone using an electrical potential applied externally. We have examined the rate of early infection in allografts following application of this technique in clinical practice. A total of 31 patients undergoing revision arthroplasty or surgery for limb salvage received 34 iontophoresed sequential allografts, of which 26 survived for a minimum of two years. The mean serum antibiotic levels after operation were low (gentamicin 0.37 mg/l (0.2 to 0.5); flucloxacillin 1 mg/l (0 to 1) and the levels in the drains were high (gentamicin 40 mg/l (2.5 to 131); flucloxacillin 17 mg/l (1 to 43). There were no early deep infections. Two late infections were presumed to be haemotogenous; 28 of the 34 allografts were retained. In 12 patients with pre-existing proven infection further infection has not occurred at a mean follow-up of 51 months (24 to 82).