MicroRNAs (miRNAs ) are small non-coding RNAs
that regulate gene expression. We hypothesised that the functions
of certain miRNAs and changes to their patterns of expression may
be crucial in the pathogenesis of nonunion. Healing fractures and
atrophic nonunions produced by periosteal cauterisation were created
in the femora of 94
Systemic antibiotics reduce infection in open
fractures. Local delivery of antibiotics can provide higher doses
to wounds without toxic systemic effects. This study investigated
the effect on infection of combining systemic with local antibiotics
via polymethylmethacrylate (PMMA) beads or gel delivery. An established Staphylococcus aureus contaminated
fracture model in
Objectives. One commonly used rat fracture model for bone and mineral research
is a closed mid-shaft femur fracture as described by Bonnarens in
1984. Initially, this model was believed to create very reproducible
fractures. However, there have been frequent reports of comminution
and varying rates of complication. Given the importance of precise
anticipation of those characteristics in laboratory research, we
aimed to precisely estimate the rate of comminution, its importance and
its effect on the amount of soft callus created. Furthermore, we
aimed to precisely report the rate of complications such as death
and infection. Methods. We tested a rat model of femoral fracture on 84
Objectives. Small animal models of fracture repair primarily investigate
indirect fracture healing via external callus formation. We present
the first described rat model of direct fracture healing. Methods. A rat tibial osteotomy was created and fixed with compression
plating similar to that used in patients. The procedure was evaluated
in 15 cadaver
Fracture repair occurs by two broad mechanisms:
direct healing, and indirect healing with callus formation. The effects
of bisphosphonates on fracture repair have been assessed only in
models of indirect fracture healing. A rodent model of rigid compression plate fixation of a standardised
tibial osteotomy was used. Ten skeletally mature Sprague–Dawley
rats received daily subcutaneous injections of 1 µg/kg ibandronate
(IBAN) and ten control
Little is known about the effect of haemorrhagic shock and resuscitation
on fracture healing. This study used a rabbit model with a femoral
osteotomy and fixation to examine this relationship. A total of 18 male New Zealand white rabbits underwent femoral
osteotomy with intramedullary fixation with ‘shock’ (n = 9) and
control (n = 9) groups. Shock was induced in the study group by
removal of 35% of the total blood volume 45 minutes before resuscitation
with blood and crystalloid. Fracture healing was monitored for eight weeks
using serum markers of healing and radiographs.Aims
Materials and Methods
Compartment syndrome, a devastating consequence
of limb trauma, is characterised by severe tissue injury and microvascular
perfusion deficits. We hypothesised that leucopenia might provide
significant protection against microvascular dysfunction and preserve
tissue viability. Using our clinically relevant rat model of compartment syndrome,
microvascular perfusion and tissue injury were directly visualised
by intravital video microscopy in leucopenic animals. We found that
while the tissue perfusion was similar in both groups (38.8% (standard
error of the mean ( Cite this article:
Compartment syndrome results from increased intra-compartmental
pressure (ICP) causing local tissue ischaemia and cell death, but
the systemic effects are not well described. We hypothesised that
compartment syndrome would have a profound effect not only on the affected
limb, but also on remote organs. Using a rat model of compartment syndrome, its systemic effects
on the viability of hepatocytes and on inflammation and circulation
were directly visualised using intravital video microscopy.Aims
Methods
The aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery. A total of 17 DBM products were used as search terms in two available databases: Embase and PubMed according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement. All articles that reported the clinical use of a DBM-product in trauma and orthopaedic related surgery were included.Objectives
Methods
Demineralised bone matrix (DBM) is rarely used for the local
delivery of prophylactic antibiotics. Our aim, in this study, was
to show that a graft with a bioactive glass and DBM combination,
which is currently available for clinical use, can be loaded with
tobramycin and release levels of antibiotic greater than the minimum
inhibitory concentration for Antibiotic was loaded into a graft and subsequently evaluated
for drug elution kinetics and the inhibition of bacterial growth.
A rat femoral condylar plug model was used to determine the effect
of the graft, loaded with antibiotic, on bone healing.Aims
Materials and Methods
The purpose of this study was to refine an accepted contaminated
rat femur defect model to result in an infection rate of approximately
50%. This threshold will allow examination of treatments aimed at
reducing infection in open fractures with less risk of type II error. Defects were created in the stablised femurs of anaethetised
rats, contaminated with Objectives
Methods
Most animal studies indicate that early irrigation
and debridement reduce infection after an open fracture. Unfortunately,
these studies often do not involve antibiotics. Clinical studies
indicate that the timing of initial debridement does not affect
the rate of infection but these studies are observational and fraught
with confounding variables. The purpose of this study was to control
these variables using an animal model incorporating systemic antibiotics
and surgical treatment. We used a rat femur model with a defect which was contaminated
with No animal that received antibiotics and surgery two hours after
injury had detectable bacteria. When antibiotics were started at
two hours, a delay in surgical treatment from two to six hours significantly
increased the development of infection (p = 0.047). However, delaying
surgery to 24 hours increase the rate of infection, but not significantly
(p = 0.054). The timing of antibiotics had a more significant effect
on the proportion of positive samples than earlier surgery. Delaying
antibiotics to six or 24 hours had a profoundly detrimental effect
on the infection rate regardless of the timing of surgery. These
findings are consistent with the concept that bacteria progress
from a vulnerable planktonic form to a treatment-resistant biofilm.
Several bisphosphonates are now available for the treatment of osteoporosis. Porous hydroxyapatite/collagen (HA/Col) composite is an osteoconductive bone substitute which is resorbed by osteoclasts. The effects of the bisphosphonate alendronate on the formation of bone in porous HA/Col and its resorption by osteoclasts were evaluated using a rabbit model. Porous HA/Col cylinders measuring 6 mm in diameter and 8 mm in length, with a pore size of 100 μm to 500 μm and 95% porosity, were inserted into a defect produced in the lateral femoral condyles of 72 rabbits. The rabbits were divided into four groups based on the protocol of alendronate administration: the control group did not receive any alendronate, the pre group had alendronate treatment for three weeks prior to the implantation of the HA/Col, the post group had alendronate treatment following implantation until euthanasia, and the pre+post group had continuous alendronate treatment from three weeks prior to surgery until euthanasia. All rabbits were injected intravenously with either saline or alendronate (7.5 μg/kg) once a week. Each group had 18 rabbits, six in each group being killed at three, six and 12 weeks post-operatively. Alendronate administration suppressed the resorption of the implants. Additionally, the mineral densities of newly formed bone in the alendronate-treated groups were lower than those in the control group at 12 weeks post-operatively. Interestingly, the number of osteoclasts attached to the implant correlated with the extent of bone formation at three weeks. In conclusion, the systemic administration of alendronate in our rabbit model at a dose-for-weight equivalent to the clinical dose used in the treatment of osteoporosis in Japan affected the mineral density and remodelling of bone tissue in implanted porous HA/Col composites.