Aims. The aims of this study were to determine the indications and
frequency of ordering a CT pulmonary angiography (CTPA) following
primary arthroplasty of the hip and knee, and to determine the number
of positive scans in these patients, the location of emboli and
the outcome for patients undergoing CTPA. Patients and Methods. We analyzed the use of CTPA, as an inpatient and up to 90 days
as an outpatient, in a cohort of patients and reviewed the medical
records and imaging for each patient undergoing CTPA. Results. Out of 11 249 patients, scans were requested in 229 (2.04%) and
86 (38%) were positive. No patient undergoing CTPA died within 90
days. The rate of mortality from pulmonary embolism (PE) overall
was 0.08%. CTPA was performed twice as often following total knee
arthroplasty (TKA) compared with total hip arthroplasty (THA), and when
performed was twice as likely to be positive. Hypoxia was the main
indication for a scan, being the indication in 149 scans (65%);
and in 23% (11 of 47), the
Aims. The aim of this study was to present data on 11 459 patients
who underwent total hip (THA), total knee (TKA) or unicompartmental
knee arthroplasty (UKA) between November 2002 and April 2014 with
aspirin as the primary agent for pharmacological thromboprophylaxis. . Patients and Methods. We analysed the incidence of deep vein thrombosis (DVT) and pulmonary
embolism (PE) then compared the 90-day all-cause mortality with
the corresponding data in the National Joint Registry for England
and Wales (NJR). . Results. The incidence of
We performed a meta-analysis of modern total
joint replacement (TJR) to determine the post-operative mortality and
the cause of death using different thromboprophylactic regimens
as follows: 1) no routine chemothromboprophylaxis (NRC); 2) Potent
anticoagulation (PA) (unfractionated or low-molecular-weight heparin, ximelagatran,
fondaparinux or rivaroxaban); 3) Potent anticoagulation combined
(PAC) with regional anaesthesia and/or pneumatic compression devices
(PCDs); 4) Warfarin (W); 5) Warfarin combined (WAC) with regional anaesthesia
and/or PCD; and 6) Multimodal (MM) prophylaxis, including regional
anaesthesia, PCDs and aspirin in low-risk patients. Cause of death
was classified as autopsy proven, clinically certain or unknown.
Deaths were grouped into cardiopulmonary excluding pulmonary embolism
(PE),
Aims. The primary aim of this study was to compare the wear properties of vitamin E-diffused, highly crosslinked polyethylene (VEPE) and one formulation of moderately crosslinked and mechanically annealed ultra-high molecular weight polyethylene (ModXLPE) in patients five years after primary total hip arthroplasty (THA). The secondary aim was to assess the clinical results of patients treated with VEPE by evaluating patient-reported outcome measures (PROMs), radiological evidence of fixation, and the incidence of mechanical failure. Patients and Methods. A total of 208 patients (221 THAs) from four international centres were recruited into a prospective study involving radiostereometric analysis (RSA) and the assessment of clinical outcomes. A total of 193 hips (87%) were reviewed at the five-year follow-up. Of these, 136 (70%) received VEPE (vs ModXLPE) liners and 68 (35%) received ceramic (vs metal) femoral heads. PROMs and radiographs were collected preoperatively and at one, two, and five years postoperatively. In addition, RSA images were collected to measure
We investigated the efficacy and safety profile of commonly used venous thromboembolism (VTE) prophylaxis agents following hip and knee arthroplasty. A systematic search of PubMed, Embase, Cochrane Library, Web of Science, and OrthoSearch was performed. Prophylaxis agents investigated were aspirin (< 325 mg and ≥ 325 mg daily), enoxaparin, dalteparin, fondaparinux, unfractionated heparin, warfarin, rivaroxaban, apixaban, and dabigatran. The primary efficacy outcome of interest was the risk of VTE, whereas the primary safety outcomes of interest were the risk of major bleeding events (MBE) and wound complications (WC). VTE was defined as the confirmed diagnosis of any deep vein thrombosis and/or pulmonary embolism. Network meta-analysis combining direct and indirect evidence was performed. Cluster rank analysis using the surface under cumulative ranking (SUCRA) was applied to compare each intervention group, weighing safety and efficacy outcomes.Aims
Methods
The aim of this study was to evaluate the healthcare costs and benefits of enoxaparin compared to aspirin in the prevention of symptomatic venous thromboembolism (VTE) after total hip arthroplasty (THA) or total knee arthroplasty (TKA) using data from the CRISTAL trial. This trial-based economic analysis reports value for money as incremental cost per quality-adjusted life-year (QALY) gained in 2022 Australian dollars, compared to a single threshold value of AUD$70,000 per QALY. Event costs were estimated based on occurrence of VTEs and bleeds, and on published guidelines for treatment. Unit costs were taken from Australian sources. QALYs were estimated using CRISTAL six-month follow-up data. Sensitivity analyses are presented that vary the cost of VTE treatment, and extend the analyses to two years.Aims
Methods
We have assessed the different adhesive properties
of some of the most common bacteria associated with periprosthetic
joint infection on various types of ultra high molecular Weight
Polyethylene (UHMWPE). Quantitative in vitro analysis
of the adhesion of biofilm producing strains of Staphylococcus
aureus and Escherichia coli to physically
and chemically characterised standard UHMWPE (PE), vitamin E blended
UHMWPE (VE-PE) and oxidised UHMWPE (OX-PE) was performed using a
sonication protocol. A significant decreased bacterial adhesion
was registered for both strains on VE-PE, in comparison with that
observed on
We calculated the rates for perioperative mortality and fatal pulmonary embolism (PE) after primary total hip replacement in a single UK health region, using a regional arthroplasty register and the tracing service of the Office of National Statistics. During 1990, there were 2111 consecutive primary replacements in 2090 separate procedures. Within 42 days of operation a total of 19 patients had died (0.91%, 95% CI 0.55 to 1.42). Postmortem examination showed that four deaths (0.19%, 95% CI 0.05 to 0.49) were definitely due to
We describe a modified lateral approach to the hip which exploits the functional continuity of gluteus medius and vastus lateralis and their dense crescentic attachment to the greater trochanter. The gluteus medius is not incised or split, but is detached and mobilised with gluteus minimus as one unit. This facilitates reattachment of the glutei and helps to preserve abductor function.
The present study aimed to investigate whether patients with inflammatory bowel disease (IBD) undergoing joint arthroplasty have a higher incidence of adverse outcomes than those without IBD. A comprehensive literature search was conducted to identify eligible studies reporting postoperative outcomes in IBD patients undergoing joint arthroplasty. The primary outcomes included postoperative complications, while the secondary outcomes included unplanned readmission, length of stay (LOS), joint reoperation/implant revision, and cost of care. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model when heterogeneity was substantial.Aims
Methods
Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters.Objectives
Methods
Total joint arthroplasty (TJA) is commonly performed in elderly
patients. Frailty, an aggregate expression of vulnerability, becomes
increasingly common with advanced age, and independently predicts
adverse outcomes and the use of resources after a variety of non-cardiac
surgical procedures. Our aim was to assess the impact of frailty
on outcomes after TJA. We analysed the impact of pre-operative frailty on death and
the use of resources after elective TJA in a population-based cohort
study using linked administrative data from Ontario, Canada.Aims
Patients and Methods
Patient function after arthroplasty should ideally quickly improve.
It is not known which peri-operative function assessments predict
length of stay (LOS) and short-term functional recovery. The objective
of this study was to identify peri-operative functions assessments
predictive of hospital LOS and short-term function after hospital discharge
in hip or knee arthroplasty patients. In total, 108 patients were assessed peri-operatively with the
timed-up-and-go (TUG), Iowa level of assistance scale, post-operative
quality of recovery scale, readiness for hospital discharge scale,
and the Western Ontario and McMaster Osteoarthritis Index (WOMAC).
The older Americans resources and services activities of daily living
(ADL) questionnaire (OARS) was used to assess function two weeks
after discharge. Objectives
Methods
As the first wave of the COVID-19 pandemic began to dip, restarting elective orthopaedics became a challenge. Protocols including surgery at ‘green’ sites, self-isolation for 14 days, and COVID-19 testing were developed to minimize the risk of transmission. In this study, we look at risk effects of 14-day self-isolation on the incidence of venous thromboembolism (VTE) in our green site hospital among patients undergoing total joint replacement (TJR). This retrospective cohort study included 50 patients who underwent TJR. Basic demographic data was collected including, age, sex, American Society of Anesthesiologists (ASA) grade, body mass index (BMI), type of surgery, and complications at two and four weeks. Univariate and multivariate analysis were used to identify risk factors associated with an increased risk of VTE.Aims
Methods
The COVID-19 pandemic posed significant challenges to healthcare systems across the globe in 2020. There were concerns surrounding early reports of increased mortality among patients undergoing emergency or non-urgent surgery. We report the morbidity and mortality in patients who underwent arthroplasty procedures during the UK first stage of the pandemic. Institutional review board approval was obtained for a review of prospectively collected data on consecutive patients who underwent arthroplasty procedures between March and May 2020 at a specialist orthopaedic centre in the UK. Data included diagnoses, comorbidities, BMI, American Society of Anesthesiologists grade, length of stay, and complications. The primary outcome was 30-day mortality and secondary outcomes were prevalence of SARS-CoV-2 infection, medical and surgical complications, and readmission within 30 days of discharge. The data collated were compared with series from the preceding three months.Aims
Methods
Chemical prophylaxis is known to reduce the venographic prevalence of deep-vein thrombosis (DVT) after total knee replacement (TKR), but it is uncertain whether this affects the incidence of symptoms. Further analysis depends on the basic epidemiology of thromboembolic symptoms. We therefore studied the pattern of such symptoms in a consecutive series of 1000 patients with primary TKR, with particular reference to risk factors and prophylaxis. We reviewed all the clinical records and contacted all the patients individually, noting risk factors, prophylaxis, symptomatic pulmonary embolus (PE) or DVT and its timing, death and its causes, and all complications. All the patients wore antiembolism stockings, 83% had regional anaesthesia and 33.9% had chemical prophylaxis. One patient died from
The aim of this study was to conduct the largest low contact stress (LCS) retrieval study to elucidate the failure mechanisms of the Porocoat and Duofix femoral component. The latter design was voluntarily recalled by the manufacturer. Uncemented LCS explants were divided into three groups: Duofix, Porocoat, and mixed. Demographics, polyethylene wear, tissue ingrowth, and metallurgical analyses were performed.Aims
Materials and Methods
Antifibrinolytic agents, including tranexamic acid (TXA) and epsilon-aminocaproic acid (EACA), have been shown to be safe and effective for decreasing perioperative blood loss and transfusion following total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, there are few prospective studies that directly compare these agents. The purpose of this study was to compare the benefits of intraoperative intravenous TXA with EACA. A total of 235 patients (90 THA and 145 TKA) were enrolled in this prospective, randomized controlled trial at a single tertiary-care referral centre. In the THA cohort, 53.3% of the patients were female with a median age of 59.8 years (interquartile range (IQR) 53.3 to 68.1). In the TKA cohort, 63.4% of the patients were female with a median age of 65.1 years (IQR 59.4 to 69.5). Patients received either TXA (n = 119) or EACA (n = 116) in two doses intraoperatively. The primary outcome measures included change in haemoglobin level and blood volume, postoperative drainage, and rate of transfusion. Secondary outcome measures included postoperative complications, cost, and length of stay (LOS).Aims
Patients and Methods
The aim of this study was to evaluate the diagnostic accuracy of the synovial alpha-defensin enzyme-linked immunosorbent assay (ELISA) for the diagnosis of prosthetic joint infection (PJI) in the work-up prior to revision of total hip (THA) and knee arthroplasty (TKA). Inclusion criteria for this prospective cohort study were acute or chronic symptoms of the index joint without specific exclusion criteria. Synovial fluid aspirates of 202 patients were analyzed and semiquantitative laboratory alpha-defensin ELISA was performed. Final diagnosis of PJI was established by examination of samples obtained during revision surgery.Aims
Patients and Methods
Positive cultures are not uncommon in cases of revision total
knee and hip arthroplasty (TKA and THA) for presumed aseptic causes.
The purpose of this study was to assess the incidence of positive
intra-operative cultures in presumed aseptic revision of TKA and
THA, and to determine whether the presence of intra-operative positive cultures
results in inferior survival in such cases. A retrospective cohort study was assembled with 679 patients
undergoing revision knee (340 cases) or hip arthroplasty (339 cases)
for presumed aseptic causes. For all patients three or more separate
intra-operative cultures were obtained. Patients were diagnosed
with a previously unsuspected prosthetic joint infection (PJI) if two
or more cultures were positive with the same organism. Records were
reviewed for demographic details, pre-operative laboratory results
and culture results. The primary outcome measure was infection-free
implant survival at two years.Aims
Patients and Methods
The aim of this study was to identify predictors of return to
work (RTW) after revision lower limb arthroplasty in patients of
working age in the United Kingdom. We assessed 55 patients aged ≤ 65 years after revision total
hip arthroplasty (THA). There were 43 women and 12 men with a mean
age of 54 years (23 to 65). We also reviewed 30 patients after revision
total knee arthroplasty (TKA). There were 14 women and 16 men with
a mean age of 58 years (48 to 64). Preoperatively, age, gender,
body mass index, social deprivation, mode of failure, length of
primary implant survival, work status and nature, activity level
(University of California, Los Angeles (UCLA) score), and Oxford
Hip and Knee Scores were recorded. Postoperatively, RTW status,
Oxford Hip and Knee Scores, EuroQol-5D (EQ-5D), UCLA score, and
Work, Osteoarthritis and Joint-Replacement Questionnaire (WORQ)
scores were obtained. Univariate and multivariate analysis was performed.Aims
Patients and Methods
To evaluate the effectiveness of an institutionally developed
algorithm for evaluation and diagnosis of prosthetic joint injection
and to determine the impact of this protocol on overall hospital
re-admissions.p We retrospectively evaluated 2685 total hip arthroplasty (THA)
and total knee arthroplasty (TKA) patients prior to (1263) and following
(1422) the introduction of an infection detection protocol. The
protocol used conservative thresholds for C-reactive protein to
direct the medical attendant to aspirate the joint. The protocol
incorporated a clear set of laboratory and clinical criteria that
allowed a patient to be discharged home if all were met. Patients were
included if they presented to our emergency department within 120
days post-operatively with concerns for swelling, pain or infection
and were excluded if they had an unambiguous infection or if their
chief complaint was non-orthopaedic in nature.Aims
Patients and Methods
There is uncertainty regarding the optimal means of thromboprophylaxis
following total hip and knee arthroplasty (THA, TKA). This systematic
review presents the evidence for acetylsalicylic acid (aspirin)
as a thromboprophylactic agent in THA and TKA and compares it with
other chemoprophylactic agents. A search of literature published between 2004 and 2014 was performed
in accordance with Preferred Reporting Items for Systematic Reviews
and Meta-Analyses guidelines. A total of 13 studies were eligible
for inclusion.Aims
Materials and Methods
The results of hip and knee replacement surgery
are generally regarded as positive for patients. Nonetheless, they are
both major operations and have recognised complications. We present
a review of relevant claims made to the National Health Service
Litigation Authority. Between 1995 and 2010 there were 1004 claims
to a value of £41.5 million following hip replacement surgery and
523 claims to a value of £21 million for knee replacement. The most common
complaint after hip surgery was related to residual neurological
deficit, whereas after knee replacement it was related to infection.
Vascular complications resulted in the highest costs per case in
each group. Although there has been a large increase in the number of operations
performed, there has not been a corresponding relative increase
in litigation. The reasons for litigation have remained largely
unchanged over time after hip replacement. In the case of knee replacement,
although there has been a reduction in claims for infection, there
has been an increase in claims for technical errors. There has also
been a rise in claims for non-specified dissatisfaction. This information
is of value to surgeons and can be used to minimise the potential
mismatch between patient expectation, informed consent and outcome. Cite this article:
Since the introduction of the National Institute
for Health and Care Excellence (NICE) guidelines on thromboprophylaxis
and the use of extended thromboprophylaxis with new oral agents,
there have been reports of complications arising as a result of
their use. We have looked at the incidence of wound complications
after the introduction of dabigatran for thromboprophylaxis in our
unit. We investigated the rate of venous thromboembolism and wound
leakage in 1728 patients undergoing primary joint replacement, both
before and after the introduction of dabigatran, and following its
subsequent withdrawal from our unit. We found that the use of dabigatran led to a significant increase
in post-operative wound leakage (20% with dabigatran, 5% with a
multimodal regimen; p <
0.001), which also resulted in an increased
duration of hospital stay. The rate of thromboembolism in patients
receiving dabigatran was higher (1.3%) than in those receiving the multimodal
thromboprophylaxis regimen, including low molecular weight heparin
as an inpatient and the extended use of aspirin (0.3%, p = 0.047).
We have ceased the use of dabigatran for thromboprophylaxis in these
patients. Cite this article:
In our department we use an enhanced recovery
protocol for joint replacement of the lower limb. This incorporates the
use of intravenous tranexamic acid (IVTA; 15 mg/kg) at the induction
of anaesthesia. Recently there was a national shortage of IVTA for
18 weeks; during this period all patients received an oral preparation
of tranexamic acid (OTA; 25 mg/kg). This retrospective study compares
the safety (surgical and medical complications) and efficacy (reduction
of transfusion requirements) of OTA and IVTA. During the study period
a total of 2698 patients received IVTA and 302 received OTA. After
adjusting for a range of patient and surgical factors, the odds
ratio (OR) of receiving a blood transfusion was significantly higher
with IVTA than with OTA (OR 0.48 (95% confidence interval 0.26 to
0.89), p = 0.019), whereas the safety profile was similar, based
on length of stay, rate of readmission, return to theatre, deep
infection, stroke, gastrointestinal bleeding, myocardial infarction,
pneumonia, deep-vein thrombosis and pulmonary embolism. The financial
benefit of OTA is £2.04 for a 70 kg patient; this is amplified when
the cost saving associated with significantly fewer blood transfusions
is considered. Although the number of patients in the study is modest, this
work supports the use of OTA, and we recommend that a randomised
trial be undertaken to compare the different methods of administering
tranexamic acid. Cite this article:
Using general practitioner records and hospital
notes and through direct telephone conversation with patients, we investigated
the accuracy of nine patient-reported complications gathered from
a self-completed questionnaire after elective joint replacement
surgery of the hip and knee. A total of 402 post-discharge complications
were reported after 8546 elective operations that were undertaken
within a three-year period. These were reported by 136 men and 240
women with a mean age of 71.8 years (34 to 93). A total of 319 reported
complications (79.4%; 95% confidence interval 75.4 to 83.3) were
confirmed to be correct. High rates of correct reporting were demonstrated
for infection (94.5%) and the need for further surgery (100%), whereas
the rates of reporting deep-vein thrombosis (DVT), pulmonary embolism,
myocardial infarction and stroke were lower (75% to 84.2%). Dislocation,
peri-prosthetic fractures and nerve palsy had modest rates of correct
reporting (36% to 57.1%). More patients who had knee surgery delivered
incorrect reports of dislocation (p = 0.001) and DVT (p = 0.013). Despite these variations, it appears that post-operative complications
may form part of a larger patient-reported outcome programme after
elective joint replacement surgery.
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.
We performed a meta-analysis to evaluate the relative efficacy of regional and general anaesthesia in patients undergoing total hip or knee replacement. A comprehensive search for relevant studies was performed in PubMed (1966 to April 2008), EMBASE (1969 to April 2008) and the Cochrane Library. Only randomised studies comparing regional and general anaesthesia for total hip or knee replacement were included. We identified 21 independent, randomised clinical trials. A random-effects model was used to calculate all effect sizes. Pooled results from these trials showed that regional anaesthesia reduces the operating time (odds ratio (OR) −0.19; 95% confidence interval (CI) −0.33 to −0.05), the need for transfusion (OR 0.45; 95% CI 0.22 to 0.94) and the incidence of thromboembolic disease (deep-vein thrombosis OR 0.45, 95% CI 0.24 to 0.84; pulmonary embolism OR 0.46, 95% CI 0.29 to 0.80). Regional anaesthesia therefore seems to improve the outcome of patients undergoing total hip or knee replacement.
The National Institute for Clinical Excellence (NICE) produces recommendations on appropriate treatment within the National Health Service (NHS) in England and Wales. The NICE guidelines on prophylaxis for venous thromboembolism in orthopaedic surgery recommend that all patients be offered a low molecular weight heparin (LMWH). The linked hospital episode statistics of 219 602 patients were examined to determine the rates of complications following lower limb arthroplasty for the 12-month periods prior to and following the publication of these guidelines. These were compared with data from the National Joint Registry (England and Wales) regarding the use of LMWH during the same periods. There was a significant increase in the reported use of LMWH (59.5% to 67.6%, p <
0.001) following the publication of the guidelines. However, the 90-day venous thromboembolism events actually increased slightly following total hip replacement (THR, 1.69% to 1.84%, p = 0.06) and remained unchanged following total knee replacement (TKR, 1.99% to 2.04%). Return to theatre in the first 30 days for infection did not show significant changes. There was an increase in the number of patients diagnosed with thrombocytopenia, which was significant following THR (0.11% to 0.16%, p = 0.04). The recommendations from NICE are based on predicted reductions in venous thromboembolism events, reducing morbidity, mortality and costs to the NHS. The early results in orthopaedic patients do not support these predictions, but do show an increase in complications.
The routine use of surgical drains in total hip arthroplasty remains controversial. They have not been shown to decrease the rate of wound infection significantly and can provide a retrograde route for it. Their use does not reduce the size or incidence of post-operative wound haematomas. This prospective, randomised study was designed to evaluate the role of drains in routine total hip arthroplasty. We investigated 552 patients (577 hips) undergoing unilateral or bilateral total hip arthroplasty who had been randomised to either having a drain for 24 hours or not having a drain. All patients followed standardised pre-, intra-, and post-operative regimes and were independently assessed using the Harris hip score before operation and at six, 18 and 36 months follow-up. The rate of superficial and deep infection was 2.9% and 0.4%, respectively, in the drained group and 4.8% and 0.7%, respectively in the undrained group. One patient in the undrained group had a haematoma which did not require drainage or transfusion. The rate of transfusion after operation in the drained group was significantly higher than for undrained procedures (p <
0.042). The use of a drain did not influence the post-operative levels of haemoglobin, the revision rates, Harris hip scores, the length of hospital stay or the incidence of thromboembolism. We conclude that drains provide no clear advantage at total hip arthroplasty, represent an additional cost, and expose patients to a higher risk of transfusion.
Patients who have undergone total hip or knee replacement (THR and TKR, respectively) are at high risk of venous thromboembolism. We aimed to determine the time courses of both the incidence of venous thromboembolism and effective prophylaxis. Patients with elective primary THR and TKR were enrolled in the multi-national Global Orthopaedic Registry. Data on the incidence of venous thromboembolism and prophylaxis were collected from 6639 THR and 8326 TKR patients. The cumulative incidence of venous thromboembolism within three months of surgery was 1.7% in the THR and 2.3% in the TKR patients. The mean times to venous thromboembolism were 21.5 days ( The risk of venous thromboembolism extends beyond the usual period of hospitalisation, while the duration of prophylaxis is often shorter than this. Practices should be re-assessed to ensure that patients receive appropriate durations of prophylaxis.