In order to compare the effect of oral apixaban
(a factor Xa inhibitor) with subcutaneous enoxaparin on major venous
thromboembolism and major and non-major clinically relevant bleeding
after total knee and hip replacement, we conducted a pooled analysis
of two previously reported double-blind randomised studies involving 8464
patients. One group received apixaban 2.5 mg twice daily (plus placebo
injection) starting 12 to 24 hours after operation, and the other
received enoxaparin subcutaneously once daily (and placebo tablets)
starting 12 hours (± 3) pre-operatively. Each regimen was continued
for 12 days ( Apixaban 2.5 mg twice daily is more effective than enoxaparin
40 mg once daily without increased bleeding.
This study evaluates the long-term survival of
spinal implants after surgical site infection (SSI) and the risk
factors associated with treatment failure. A Kaplan-Meier survival analysis was carried out on 43 patients
who had undergone a posterior spinal fusion with instrumentation
between January 2006 and December 2008, and who consecutively developed
an acute deep surgical site infection. All were appropriately treated
by surgical debridement with a tailored antibiotic program based
on culture results for a minimum of eight weeks. A ‘terminal event’ or failure of treatment was defined as implant
removal or death related to the SSI. The mean follow-up was 26 months
(1.03 to 50.9). A total of ten patients (23.3%) had a terminal event.
The rate of survival after the first debridement was 90.7% (95%
confidence interval (CI) 82.95 to 98.24) at six months, 85.4% (95%
CI 74.64 to 96.18) at one year, and 73.2% (95% CI 58.70 to 87.78)
at two, three and four years. Four of nine patients required re-instrumentation
after implant removal, and two of the four had a recurrent infection
at the surgical site. There was one recurrence after implant removal
without re-instrumentation. Multivariate analysis revealed a significant risk of treatment
failure in patients who developed sepsis (hazard ratio (HR) 12.5
(95% confidence interval (CI) 2.6 to 59.9); p <
0.001) or who
had >
three fused segments (HR 4.5 (95% CI 1.25 to 24.05); p = 0.03).
Implant survival is seriously compromised even after properly treated
surgical site infection, but progressively decreases over the first
24 months. Cite this article:
We report the results of revision total knee
replacement (TKR) in 26 patients with major metaphyseal osteolytic defects
using 29 trabecular metal cones in conjunction with a rotating hinged
total knee prosthesis. The osteolytic defects were types II and
III (A or B) according to the Anderson Orthopaedic Research Institute
(AORI) classification. The mean age of the patients was 72 years
(62 to 84) and there were 15 men and 11 women. In this series patients had
undergone a mean of 2.34 previous total knee arthroplasties. The
main objective was to restore anatomy along with stability and function
of the knee joint to allow immediate full weight-bearing and active
knee movement. Outcomes were measured using Knee Society scores,
Oxford knee scores, range of movement of the knee and serial radiographs.
Patients were followed for a mean of 36 months (24 to 49). The mean
Oxford knee clinical scores improved from 12.83 (10 to 15) to 35.20
(32 to 38) (p <
0.001) and mean American Knee Society scores
improved from 33.24 (13 to 36) to 81.12 (78 to 86) (p <
0.001).
No radiolucent lines suggestive of loosening were seen around the trabecular
metal cones, and by one year all the radiographs showed good osteo-integration.
There was no evidence of any collapse or implant migration. Our
early results confirm the findings of others that trabecular metal
cones offer a useful way of managing severe bone loss in revision
TKR. Cite this article:
We report on the long-term results of 163 bicruciate-retaining
Hermes 2C total knee replacements in 130 patients at a mean follow-up
of 22.4 years (20.3 to 23.5). Even when the anterior cruciate ligament
had a partially degenerative appearance it was preserved as long
as the knee had a normal anterior drawer and Lachman’s test pre-operatively. The
description and surgical technique of this minimally constrained
prosthesis were published in 1983 and the ten-year clinical results
in 1999. A total of 12% of the knees (20 of 163) in this study were revised
because of wear of the polyethylene tibial insert. Excellent stability
was achieved and the incidence of aseptic component loosening was
4.3% (seven of 163). The survival rate using revision for any reason
as the endpoint was 82% (95% confidence interval 76.2 to 88.0). Although this series included a relatively small number of replacements,
it demonstrated that the anterior cruciate ligament, even when partially
degenerated at the time of TKR, remained functional and provided
adequate stability at a long-term follow-up. Cite this article:
This review summarises the opinions and conclusions
reached from a symposium on infected total knee replacement (TKR)
held at the British Association of Surgery of the Knee (BASK) annual
meeting in 2011. The National Joint Registry for England and Wales
reported 5082 revision TKRs in 2010, of which 1157 (23%) were caused
by infection. The diagnosis of infection beyond the acute post-operative
stage relies on the identification of the causative organism by
aspiration and analysis of material obtained at arthroscopy. Ideal
treatment then involves a two-stage surgical procedure with extensive
debridement and washout, followed by antibiotics. An articulating
or non-articulating drug-eluting cement spacer is used prior to
implantation of the revision prosthesis, guided by the serum level
of inflammatory markers. The use of a single-stage revision is gaining popularity
and we would advocate its use in certain patients where the causative
organism is known, no sinuses are present, the patient is not immunocompromised,
and there is no radiological evidence of component loosening or
osteitis. It is our opinion that single-stage revision produces high-quality
reproducible results and will soon achieve the same widespread acceptance
as it does in infected hip arthroplasty.
The purpose of this study was twofold: first,
to determine whether the five-year results of hip resurfacing arthroplasty
(HRA) in Canada justified the continued use of HRA; and second,
to identify whether greater refinement of patient selection was
warranted. This was a retrospective cohort study that involved a review
of 2773 HRAs performed between January 2001 and December 2008 at
11 Canadian centres. Cox’s proportional hazards models were used
to analyse the predictors of failure of HRA. Kaplan–Meier survival
analysis was performed to predict the cumulative survival rate at
five years. The factors analysed included age, gender, body mass
index, pre-operative hip pathology, surgeon’s experience, surgical
approach, implant sizes and implant types. The most common modes
of failure were also analysed. The 2773 HRAs were undertaken in 2450 patients: 2127 in men and
646 in women. The mean age at operation was 50.5 years ( The failure rates of HRA at five years justify the ongoing use
of this technique in men. Female gender is an independent predictor
of failure, and a higher failure rate at five years in women leads
the authors to recommend this technique only in exceptional circumstances
for women. Cite this article:
We report the results at a mean of 24.3 years
(20 to 32) of 61 previously reported consecutive total hip replacements carried
out on 44 patients with severe congenital hip disease, performed
with reconstruction of the acetabulum with an impaction grafting
technique known as cotyloplasty. The mean age of the patients at
operation was 46.7 years (23 to 68) and all were women. The patients
were followed post-operatively for a mean of 24.3 years (20 to 32), using
the Merle d’Aubigné and Postel scoring system as modified by Charnley,
and with serial radiographs. At the time of the latest follow-up,
28 acetabular components had been revised because of aseptic loosening
at a mean of 15.9 years (6 to 26), and one at 40 days after surgery
because of repeated dislocations. The overall survival rate for aseptic
failure of the acetabular component at ten years was 93.1% (95%
confidence interval (CI) 86.5 to 96.7) when 53 hips were at risk,
and at 23 years was 56.1% (95% CI 49.4 to 62.8), when 22 hips remained
at risk. These long-term results are considered satisfactory for
the reconstruction of an acetabulum presenting with inadequate bone
stock and circumferential segmental defects. Cite this article:
Stress shielding resulting in diminished bone
density following total knee replacement (TKR) may increase the
risk of migration and loosening of the prosthesis. This retrospective
study was designed to quantify the effects of the method of fixation
on peri-prosthetic tibial bone density beneath cemented and uncemented
tibial components of similar design and with similar long-term survival
rates. Standard radiographs taken between two months and 15 years
post-operatively were digitised from a matched group of TKRs using
cemented (n = 67) and uncemented (n = 67) AGC tibial prostheses.
Digital radiograph densitometry was used to quantify changes in
bone density over time. Age, length of follow-up, gender, body mass
index and alignment each significantly influenced the long-term
pattern of peri-prosthetic bone density. Similar long-term changes
in density irrespective of the method of fixation correlated well
with the high rate of survival of this TKR at 20 years, and suggest
that cemented and uncemented fixation are both equally viable. Cite this article:
The June 2013 Knee Roundup360 looks at: knee arthroplasty in diabetic patients; whether TKR is a timebomb; the use of antidepressants for knee OA; trochleoplasty; articulated spacers; mental health and joint replacement; and the use of physiotherapy for meniscal tear.
We retrospectively analysed concentrations of chromium and cobalt ions in samples of synovial fluid and whole blood taken from a group of 92 patients with failed current-generation metal-on-metal hip replacements. We applied acid oxidative digestion to our trace metal analysis protocol, which found significantly higher levels of metal ion concentrations in blood and synovial fluid than a non-digestive method. Patients were subcategorised by mode of failure as either ‘unexplained pain’ or ‘defined causes’. Using this classification, chromium and cobalt ion levels were present over a wider range in synovial fluid and not as strongly correlated with blood ion levels as previously reported. There was no significant difference between metal ion concentrations and manufacturer of the implant, nor femoral head size below or above 50 mm. There was a moderately positive correlation between metal ion levels and acetabular component inclination angle as measured on three-dimensional CT imaging. Our results suggest that acid digestion of samples of synovial fluid samples is necessary to determine metal ion concentrations accurately so that meaningful comparisons can be made between studies.
To quantify and compare peri-acetabular bone mineral density
(BMD) between a monoblock acetabular component using a metal-on-metal
(MoM) bearing and a modular titanium shell with a polyethylene (PE)
insert. The secondary outcome was to measure patient-reported clinical
function. A total of 50 patients (25 per group) were randomised to MoM
or metal-on-polyethlene (MoP). There were 27 women (11 MoM) and
23 men (14 MoM) with a mean age of 61.6 years (47.7 to 73.2). Measurements
of peri-prosthetic acetabular and contralateral hip (covariate)
BMD were performed at baseline and at one and two years’ follow-up.
The Western Ontario and McMaster Universities osteoarthritis index
(WOMAC), University of California, Los Angeles (UCLA) activity score,
Harris hip score, and RAND-36 were also completed at these intervals.Objectives
Methods
The Oxford hip score (OHS) is a 12-item questionnaire designed
and developed to assess function and pain from the perspective of
patients who are undergoing total hip replacement (THR). The OHS
has been shown to be consistent, reliable, valid and sensitive to
clinical change following THR. It has been translated into different
languages, but no adequately translated, adapted and validated Danish
language version exists. The OHS was translated and cross-culturally adapted into Danish
from the original English version, using methods based on best-practice
guidelines. The translation was tested for psychometric quality
in patients drawn from a cohort from the Danish Hip Arthroplasty
Register (DHR).Objectives
Methods
The term developmental dysplasia of the hip (DDH)
describes a spectrum of disorders that results in abnormal development
of the hip joint. If not treated successfully in childhood, these
patients may go on to develop hip symptoms and/or secondary osteoarthritis
in adulthood. In this review we describe the altered anatomy encountered
in adults with DDH along with the management options, and the challenges
associated with hip arthroscopy, osteotomies and arthroplasty for
the treatment of DDH in young adults. Cite this article:
Metallosis is a rare cause of failure after total knee replacement and has only previously been reported when there has been abnormal metal-on-metal contact. We describe 14 patients (15 knees) whose total knee replacement required revision for a new type of early failure caused by extensive metallosis. A modification of a cementless rotating platform implant, which had previously had excellent long-term survival, had been used in each case. The change was in the form of a new porous-beaded surface on the femoral component to induce cementless fixation, which had been used successfully in the fixation of acetabular and tibial components. This modification appeared to have resulted in metallosis due to abrasive two-body wear. The component has subsequently been recalled and is no longer in use. The presentation, investigation, and findings at revision are described and a possible aetiology and its implications are discussed.
This editorial considers the shortcomings of assessing outcome after joint replacement only by the survival of the implant.
We report a systematic review and meta-analysis
of the peer-reviewed literature focusing on metal sensitivity testing
in patients undergoing total joint replacement (TJR). Our purpose
was to assess the risk of developing metal hypersensitivity post-operatively
and its relationship with outcome and to investigate the advantages
of performing hypersensitivity testing. We undertook a comprehensive search of the citations quoted in
PubMed and EMBASE: 22 articles (comprising 3634 patients) met the
inclusion criteria. The frequency of positive tests increased after
TJR, especially in patients with implant failure or a metal-on-metal
coupling. The probability of developing a metal allergy was higher
post-operatively (odds ratio (OR) 1.52 (95% confidence interval
(CI) 1.06 to 2.31)), and the risk was further increased when failed
implants were compared with stable TJRs (OR 2.76 (95% CI 1.14 to
6.70)). Hypersensitivity testing was not able to discriminate between
stable and failed TJRs, as its predictive value was not statistically
proven. However, it is generally thought that hypersensitivity testing
should be performed in patients with a history of metal allergy
and in failed TJRs, especially with metal-on-metal implants and
when the cause of the loosening is doubtful.
The purpose of this study was to examine the
complications and outcomes of total hip replacement (THR) in super-obese
patients (body mass index (BMI) >
50 kg/m2) compared
with class I obese (BMI 30 to 34.9 kg/m2) and normal-weight
patients (BMI 18.5 to 24.9 kg/m2), as defined by the
World Health Organization. A total of 39 THRs were performed in 30 super-obese patients
with a mean age of 53 years (31 to 72), who were followed for a
mean of 4.2 years (2.0 to 11.7). This group was matched with two
cohorts of normal-weight and class I obese patients, each comprising
39 THRs in 39 patients. Statistical analysis was performed to determine differences
among these groups with respect to complications and satisfaction
based on the Western Ontario and McMaster Universities (WOMAC) osteoarthritis
index, the Harris hip score (HHS) and the Short-Form (SF)-12 questionnaire. Super-obese patients experienced significantly longer hospital
stays and higher rates of major complications and readmissions than
normal-weight and class I obese patients. Although super-obese patients
demonstrated reduced pre-operative and post-operative satisfaction
scores, there was no significant difference in improvement, or change in
the score, with respect to HHS or the WOMAC osteoarthritis index. Super-obese patients obtain similar satisfaction outcomes as
class I obese and normal-weight patients with respect to improvement
in their scores. However, they experience a significant increase
in length of hospital stay and major complication and readmission
rates. Cite this article:
Cut-off values with highest sensitivity and specificity
for the synovial fluid white cell and differential count will facilitate
the accurate diagnosis of infection in total knee (TKR) and total
hip replacement (THR). All patients undergoing revision TKR or THR
for suspected prosthetic joint infection between 2009 and 2011 at
two hospitals were identified. A total of 75 patients were included
with a mean age of 70.3 years (38 to 89). Synovial fluid was aspirated
pre-operatively and peri-prosthetic tissue samples were taken intra-operatively
for histological and microbiological examination. Receiver operating characteristic (ROC) plots were constructed
for white cell and differential counts in aspirated fluid. The optimal
cut-off for TKR and THR was 1590 white cells/µl and 65% neutrophilia.
The white cell count cut-off value identified for THR was notably
lower than previously quoted in the literature. A cut-off value
for white cell count in synovial aspirate in suspected prosthetic
joint infection of between 1100 and 1700 white cells/µl is likely
to be applicable to both THR and TKR. Cite this article:
In a retrospective cohort study we compared the
clinical outcome and complications, including dysphagia, following
anterior cervical fusion for the treatment of cervical spondylosis
using either a zero-profile (Zero-P; Synthes) implant or an anterior
cervical plate and cage. A total of 83 patients underwent fusion
using a Zero-P and 107 patients underwent fusion using a plate and
cage. The mean follow-up was 18.6 months ( When compared with the traditional anterior cervical plate and
cage, the Zero-P implant is a safe and convenient procedure giving
good results in patients with symptomatic cervical spondylosis with
a reduced incidence of dysphagia post-operatively. Cite this article: