We wanted to investigate regional variations in the organisms
reported to be causing peri-prosthetic infections and to report
on prophylaxis regimens currently in use across England. Analysis of data routinely collected by Public Health England’s
(PHE) national surgical site infection database on elective primary
hip and knee arthroplasty procedures between April 2010 and March
2013 to investigate regional variations in causative organisms.
A separate national survey of 145 hospital Trusts (groups of hospitals
under local management) in England routinely performing primary
hip and/or knee arthroplasty was carried out by standard email questionnaire.Objectives
Methods
Older patients with multiple medical co-morbidities
are increasingly being offered and undergoing total joint arthroplasty
(TJA). These patients are more likely to require intensive care
support, following surgery. We prospectively evaluated the need
for intensive care admission and intervention in a consecutive series
of 738 patients undergoing elective hip and knee arthroplasty procedures.
The mean age was 60.6 years (18 to 91; 440 women, 298 men. Risk
factors, correlating with the need for critical care intervention,
according to published guidelines, were analysed to identify high-risk
patients who would benefit from post-operative critical care monitoring.
A total of 50 patients (6.7%) in our series required critical care
level interventions during their hospital stay. Six independent
multivariate clinical predictors were identified (p <
0.001)
including a history of congestive heart failure (odds ratio (OR)
24.26, 95% confidence interval (CI) 9.51 to 61.91), estimated blood
loss >
1000 mL (OR 17.36, 95% CI 5.36 to 56.19), chronic obstructive
pulmonary disease (13.90, 95% CI 4.78 to 40.36), intra-operative
use of vasopressors (OR 8.10, 95% CI 3.23 to 20.27), revision hip
arthroplasty (OR 2.71, 95% CI 1.04 to 7.04) and body mass index
>
35 kg/m2 (OR 2.70, 95% CI 123 to 5.94). The model was
then validated against an independent, previously published data
set of 1594 consecutive patients. The use of this risk stratification
model can be helpful in predicting which high-risk patients would
benefit from a higher level of monitoring and care after elective
TJA and aid hospitals in allocating precious critical care resources. Cite this article:
This study reports the application of a novel method for quantitatively determining differences in the mechanical properties of healthy and torn rotator cuff tissues. In order to overcome problems of stress risers at the grip-tendon interface that can obscure mechanical measurements of small tendons, we conducted our investigation using dynamic shear analysis. Rotator cuff tendon specimens were obtained from 100 patients during shoulder surgery. They included 82 differently sized tears and 18 matched controls. We subjected biopsy samples of 3 mm in diameter to oscillatory deformation under compression using dynamic shear analysis. The storage modulus (G’) was calculated as an indicator of mechanical integrity. Normal tendons had a significantly higher storage modulus than torn tendons, indicating that torn tendons are mechanically weaker than normal tendons (p = 0.003). Normal tendons had a significantly higher mean shear modulus than tendons with massive tears (p <
0.01). Dynamic shear analysis allows the determination of shear mechanical properties of small tissue specimens obtained intra-operatively that could not be studied by conventional methods of tensile testing. These methods could be employed to investigate other musculoskeletal tissues. This pilot study provides some insight into mechanisms that might contribute to the failure of repair surgery, and with future application could help direct the most appropriate treatment for specific rotator cuff tears.
This review explores recent advances in fixator design and used in contemporary orthopaedic practice including the management of bone loss, complex deformity and severe isolated limb injury.
The June 2015 Oncology Roundup360 looks at: Infection in megaprosthesis; Impressive results for mid femoral reconstruction; Revered teaching or old myth? Femoral neck protection in metastatic disease; Megaprosthesis about the knee; Malignant transformation in multiple hereditary exostoses; Fracture of intercalary bone allograft; Comorbidity and outcomes in sarcoma; A worrying turn? Use of denosumab for giant cell tumour of bone
We developed a method of applying vibration to the impaction bone grafting process and assessed its effect on the mechanical properties of the impacted graft. Washed morsellised bovine femoral heads were impacted into shear test rings. A range of frequencies of vibration was tested, as measured using an accelerometer housed in a vibration chamber. Each shear test was repeated at four different normal loads to generate stress-strain curves. The Mohr-Coulomb failure envelope from which shear strength and interlocking values are derived was plotted for each test. The experiments were repeated with the addition of blood in order to replicate a saturated environment. Graft impacted with the addition of vibration at all frequencies showed improved shear strength when compared with impaction without vibration, with 60 Hz giving the largest effect. Under saturated conditions the addition of vibration was detrimental to the shear strength of the aggregate. The civil-engineering principles of particulate settlement and interlocking also apply to impaction bone grafting. Although previous studies have shown that vibration may be beneficial in impaction bone grafting on the femoral side, our study suggests that the same is not true in acetabular revision.
Biofilm-associated infections in wounds or on implants are difficult to treat. Eradication of the bacteria is nearly always impossible, despite the use of specific antibiotics. The bactericidal effects of high-energy extracorporeal shock waves on The biofilm-cultured washers were exposed to low-energy shock waves at 0.16 mJ/mm2 for 500 impulses. The washers were then treated with cefuroxime, rifampicin and fosfomycin, both alone and in combination. All tests were carried out in triplicate. Viable cells were counted to determine the bactericidal effect. The control groups of We conclude that shock waves combined with antibiotics could be tested in an
This randomised trial evaluated the outcome of
a single design of unicompartmental arthroplasty of the knee (UKA) with
either a cemented all-polyethylene or a metal-backed modular tibial
component. A total of 63 knees in 45 patients (17 male, 28 female)
were included, 27 in the all-polyethylene group and 36 in the metal-backed
group. The mean age was 57.9 years (39.6 to 76.9). At a mean follow-up
of 6.4 years (5 to 9.9), 11 all-polyethylene components (41%) were
revised (at a mean of 5.8 years; 1.4 to 8.0) post-operatively and
two metal-backed components were revised (at one and five years).
One revision in both groups was for unexplained pain, one in the
metal-backed group was for progression of osteoarthritis. The others
in the all-polyethylene group were for aseptic loosening. The survivorship
at seven years calculated by the Kaplan–Meier method for the all-polyethylene
group was 56.5% (95% CI 31.9 to 75.2, number at risk 7) and for
the metal-backed group was 93.8% (95% CI 77.3 to 98.4, number at
risk 16) This difference was statistically significant (p <
0.001).
At the most recent follow-up, significantly better mean Western
Ontario and McMaster Universities Arthritis Index Scores were found
in the all-polyethylene group (13.4 This randomised study demonstrates that all-polyethylene components
in this design of fixed bearing UKA had unsatisfactory results with
significantly higher rates of failure before ten years compared
with the metal-back components. Cite this article:
The anatomy and microstructure of the menisci
allow the effective distribution of load across the knee. Meniscectomy
alters the biomechanical environment and is a potent risk factor
for osteoarthritis. Despite a trend towards meniscus-preserving
surgery, many tears are irreparable, and many repairs fail. Meniscal allograft transplantation has principally been carried
out for pain in patients who have had a meniscectomy. Numerous case
series have reported a significant improvement in patient-reported
outcomes after surgery, but randomised controlled trials have not
been undertaken. It is scientifically plausible that meniscal allograft transplantation
is protective of cartilage, but this has not been established clinically
to date. Cite this article:
There remains conflicting evidence regarding cortical bone strength
following bisphosphonate therapy. As part of a study to assess the
effects of bisphosphonate treatment on the healing of rat tibial
fractures, the mechanical properties and radiological density of
the uninjured contralateral tibia was assessed. Skeletally mature aged rats were used. A total of 14 rats received
1µg/kg ibandronate (iban) daily and 17 rats received 1 ml 0.9% sodium
chloride (control) daily. Stress at failure and toughness of the
tibial diaphysis were calculated following four-point bending tests.Objectives
Methods
We describe the technique and results of medial
submuscular plating of the femur in paediatric patients and discuss its
indications and limitations. Specifically, the technique is used
as part of a plate-after-lengthening strategy, where the period
of external fixation is reduced and the plate introduced by avoiding
direct contact with the lateral entry wounds of the external fixator
pins. The technique emphasises that vastus medialis is interposed
between the plate and the vascular structures. A total of 16 patients (11 male and five female, mean age 9.6
years (5 to 17)), had medial submuscular plating of the femur. All
underwent distraction osteogenesis of the femur with a mean lengthening
of 4.99 cm (3.2 to 12) prior to plating. All patients achieved consolidation
of the regenerate without deformity. The mean follow-up was 10.5 months
(7 to 15) after plating for those with plates still Placing the plate on the medial side is advantageous when the
external fixator is present on the lateral side, and is biomechanically
optimal in the presence of a femoral defect. We conclude that medial
femoral submuscular plating is a useful technique for specific indications
and can be performed safely with a prior understanding of the regional
anatomy. Cite this article:
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 measured the tension in the interosseous membrane
in six cadaveric forearms using an Cite this article:
Construction of a functional skeleton is accomplished
through co-ordination of the developmental processes of chondrogenesis,
osteogenesis, and synovial joint formation. Infants whose movement Cite this article:
Aseptic loosening of the acetabular component continues to be the most common indication for revision of total hip replacements in younger patients. Early in the evolution of the cemented hip, arthroplasty surgeons switched from removal to retention of the acetabular subchondral bone plate, theorising that unfavourable mechanical forces were the cause of loosening at the bone-cement interface. It is now known that the cause of aseptic loosening is probably biological rather than mechanical and removing the subchondral bone plate may enhance biological fixation of cement to bone. With this in mind, perhaps it is time to revive removal of the subchondral bone as a standard part of acetabular preparation.
Although it has been suggested that the outcome
after revision of a unicondylar knee replacement (UKR) to total knee
replacement (TKR) is better when the mechanism of failure is understood,
a comparative study on this subject has not been undertaken. A total of 30 patients (30 knees) who underwent revision of their
unsatisfactory UKR to TKR were included in the study: 15 patients
with unexplained pain comprised group A and 15 patients with a defined
cause for pain formed group B. The Oxford knee score (OKS), visual
analogue scale for pain (VAS) and patient satisfaction were assessed before
revision and at one year after revision, and compared between the
groups. The mean OKS improved from 19 (10 to 30) to 25 (11 to 41) in
group A and from 23 (11 to 45) to 38 (20 to 48) in group B. The
mean VAS improved from 7.7 (5 to 10) to 5.4 (1 to 8) in group A
and from 7.4 (2 to 9) to 1.7 (0 to 8) in group B. There was a statistically
significant difference between the mean improvements in each group
for both OKS (p = 0.022) and VAS (p = 0.002). Subgroup analysis
in group A, performed in order to define a patient factor that predicts
outcome of revision surgery in patients with unexplained pain, showed
no pre-operative differences between both subgroups. These results may be used to inform patients about what to expect
from revision surgery, highlighting that revision of UKR to TKR
for unexplained pain generally results in a less favourable outcome
than revision for a known cause of pain. Cite this article:
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. A rat tibial osteotomy was created and fixed with compression
plating similar to that used in patients. The procedure was evaluated
in 15 cadaver rats and then Objectives
Methods
In this Cite this article:
Stress fractures occurring in the pubis and ischium
after peri-acetabular osteotomy (PAO) are not well recognised, with
a reported incidence of 2% to 3%. The purpose of this study was
to analyse the incidence of stress fracture after Bernese PAO under
the care of two high-volume surgeons. The study included 359 patients
(48 men, 311 women) operated on at a mean age of 31.1 years (15
to 56), with a mean follow-up of 26 months (6 to 64). Complete follow-up
radiographs were available for 348 patients, 64 of whom (18.4%)
developed a stress fracture of the inferior pubic ramus, which was
noted at a mean of 9.1 weeks (5 to 55) after surgery. Most (58;
91%) healed. In 40 of the patients with a stress fracture (62.5%),
pubic nonunion also occurred. Those with a stress fracture were
significantly older (mean 33.9 years (16 to 50) Cite this article: