Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to < -3000 µε (pathological loading) and < -7000 µε (yield point) minimum principal (compressive) microstrain and > 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed.Objectives
Materials and Methods
The MAGnetic Expansion Control (MAGEC) system
is used increasingly in the management of early-onset scoliosis.
Good results have been published, but there have been recent reports
identifying implant failures that may be associated with significant
metallosis surrounding the implants. This article aims to present
the current knowledge regarding the performance of this implant,
and the potential implications and strategies that may be employed
to identify and limit any problems. We urge surgeons to apply caution to patient and construct selection;
engage in prospective patient registration using a spine registry;
ensure close clinical monitoring until growth has ceased; and send
all explanted MAGEC rods for independent analysis. The MAGEC system may be a good instrumentation system for the
treatment of early-onset scoliosis. However, it is innovative and
like all new technology, especially when deployed in a paediatric
population, robust systems to assess long-term outcome are required
to ensure that patient safety is maintained. Cite this article:
To determine the outcomes following revision surgery of metal-on-metal
hip arthroplasties (MoMHA) performed for adverse reactions to metal
debris (ARMD), and to identify factors predictive of re-revision. We performed a retrospective observational study using National
Joint Registry (NJR) data on 2535 MoMHAs undergoing revision surgery
for ARMD between 2008 and 2014. The outcomes studied following revision were
intra-operative complications, mortality and re-revision surgery.
Predictors of re-revision were identified using competing-risk regression
modelling.Aims
Patients and Methods
In the initial development of total shoulder arthroplasty (TSA),
the humeral component was usually fixed with cement. Cementless
components were subsequently introduced. The aim of this study was
to compare the long-term outcome of cemented and cementless humeral
components in arthroplasty of the shoulder. All patients who underwent primary arthroplasty of the shoulder
at our institution between 1970 and 2012 were included in the study.
There were 4636 patients with 1167 cemented humeral components and
3469 cementless components. Patients with the two types of fixation
were matched for nine different covariates using a propensity score
analysis. A total of 551 well-balanced pairs of patients with cemented
and cementless components were available after matching for comparison
of the outcomes. The clinical outcomes which were analysed included loosening
of the humeral component determined at revision surgery, periprosthetic
fractures, post-operative infection and operating time.Aims
Patients and Methods
The most effective surgical approach for total hip arthroplasty
(THA) remains controversial. The direct anterior approach may be
associated with a reduced risk of dislocation, faster recovery,
reduced pain and fewer surgical complications. This systematic review
aims to evaluate the current evidence for the use of this approach
in THA. Following the Cochrane collaboration, an extensive literature
search of PubMed, Medline, Embase and OvidSP was conducted. Randomised
controlled trials, comparative studies, and cohort studies were
included. Outcomes included the length of the incision, blood loss,
operating time, length of stay, complications, and gait analysis.Aims
Materials and Methods
Infection of implants is a major problem in elective and trauma surgery. Heating is an effective way to reduce the bacterial load in food preparation, and studies on hyperthermia treatment for cancer have shown that it is possible to heat metal objects with pulsed electromagnetic fields selectively (PEMF), also known as induction heating. We therefore set out to answer the following research question: is non-contact induction heating of metallic implants effective in reducing bacterial load Titanium alloy cylinders (Ti6Al4V) were exposed to PEMF from an induction heater with maximum 2000 watts at 27 kHz after being contaminated with five different types of micro-organisms: Objectives
Methods
Oxidised zirconium was introduced as a material for femoral components
in total knee arthroplasty (TKA) as an attempt to reduce polyethylene
wear. However, the long-term survival of this component is not known. We performed a retrospective review of a prospectively collected
database to assess the ten year survival and clinical and radiological
outcomes of an oxidised zirconium total knee arthroplasty with the
Genesis II prosthesis. The Western Ontario and McMaster Universities Osteoarthritis
Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS)
and a patient satisfaction scale were used to assess outcome.Aims
Methods
There is a large amount of evidence available
about the relative merits of unicompartmental and total knee arthroplasty
(UKA and TKA). Based on the same evidence, different people draw
different conclusions and as a result, there is great variability
in the usage of UKA. The revision rate of UKA is much higher than TKA and so some
surgeons conclude that UKA should not be performed. Other surgeons
believe that the main reason for the high revision rate is that
UKA is easy to revise and, therefore, the threshold for revision
is low. They also believe that UKA has many advantages over TKA
such as a faster recovery, lower morbidity and mortality and better
function. They therefore conclude that UKA should be undertaken
whenever appropriate. The solution to this argument is to minimise the revision rate
of UKA, thereby addressing the main disadvantage of UKA. The evidence
suggests that this will be achieved if surgeons use UKA for at least
20% of their knee arthroplasties and use implants that are appropriate
for these broad indications. Cite this article:
The goals of this study were to define the risk factors, nature,
chronology, and treatment strategies adopted for periprosthetic
femoral fractures in 32 644 primary total hip arthroplasties (THAs). There were 564 intra-operative fractures (1.7%); 529 during uncemented
stem placement (3.0%) and 35 during cemented stem placement (0.23%).
Intra-operative fractures were more common in females and patients
over 65 years (p <
0.001). The majority occurred during placement
of the femoral component (60%), and involved the calcar (69%). There
were 557 post-operative fractures (20-year probability: 3.5%; 95%
confidence interval (CI) 3.2 to 3.9); 335 fractures after placement
of an uncemented stem (20-year probability: 7.7%; 95% CI 6.2 to
9.1) and 222 after placement of a cemented stem (20-year probability:
2.1%; 95% CI 1.8 to 2.5). The probability of a post-operative fracture
within 30 days after an uncemented stem was ten times higher than
a cemented stem. The most common post-operative fracture type was
a Vancouver AG (32%; n = 135), with 67% occurring after
a fall. In all, 36% (n = 152) were treated with revision arthroplasty. Aim and Methods
Results
Anatomical total knee arthroplasty alignment
Joint replacement of the hip and knee remain
very satisfactory operations. They are, however, expensive. The
actual manufacturing of the implant represents only 30% of the final
cost, while sales and marketing represent 40%. Recently, the patents
on many well established and successful implants have expired. Companies
have started producing and distributing implants that purport to
replicate existing implants with good long-term results. The aims of this paper are to assess the legality, the monitoring
and cost saving implications of such generic implants. We also assess
how this might affect the traditional orthopaedic implant companies. Cite this article:
Preservation of posterior condylar offset (PCO) has been shown to correlate with improved functional results after primary total knee arthroplasty (TKA). Whether this is also the case for revision TKA, remains unknown. The aim of this study was to assess the independent effect of PCO on early functional outcome after revision TKA. A total of 107 consecutive aseptic revision TKAs were performed by a single surgeon during an eight-year period. The mean age was 69.4 years (39 to 85) and there were 59 female patients and 48 male patients. The Oxford Knee Score (OKS) and Short-form (SF)-12 score were assessed pre-operatively and one year post-operatively. Patient satisfaction was also assessed at one year. Joint line and PCO were assessed radiographically at one year.Objectives
Methods
We recently published a paper comparing the incidence
of adverse outcomes after unicompartmental and total knee arthroplasty
(UKA and TKA). The conclusion of this study, which was in favour
of UKA, was dismissed as “biased” in a review in Cite this article:
