Although patients with a history of venous thromboembolism
(VTE) who undergo
The June 2023 Research Roundup. 360. looks at: Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee; Predicted waiting times for orthopaedic surgery: an urgent need to address the deficit in capacity; Vascular impulse technology versus elevation for reducing the swelling of upper and
Complex joint fractures of the lower extremity are often accompanied by soft-tissue swelling and are associated with prolonged hospitalization and soft-tissue complications. The aim of the study was to evaluate the effect of vascular impulse technology (VIT) on soft-tissue conditioning in comparison with conventional elevation. A total of 100 patients were included in this prospective, randomized, controlled monocentre study allocated to the three subgroups of dislocated ankle fracture (n = 40), pilon fracture (n = 20), and intra-articular calcaneal fracture (n = 40). Patients were randomized to the two study groups in a 1:1 ratio. The effectiveness of VIT (intervention) compared with elevation (control) was analyzed separately for the whole study population and for the three subgroups. The primary endpoint was the time from admission until operability (in days).Aims
Methods
Aims. There is concern that aggressive target pricing in the new Bundled Payment for Care Improvement Advanced (BPCI-A) penalizes high-performing groups that had achieved low costs through prior experience in bundled payments. We hypothesize that this methodology incorporates unsustainable downward trends on Target Prices and will lead to groups opting out of BPCI Advanced in favour of a traditional fee for service. Methods. Using the Centers for Medicare and Medicaid Services (CMS) data, we compared the Target Price factors for hospitals and physician groups that participated in both BPCI Classic and BPCI Advanced (legacy groups), with groups that only participated in BPCI Advanced (non-legacy). With rebasing of Target Prices in 2020 and opportunity for participants to drop out, we compared retention rates of hospitals and physician groups enrolled at the onset of BPCI Advanced with current enrolment in 2020. Results. At its peak in July 2015, 342 acute care hospitals and physician groups participated in
In this systematic review, our aim was to explore
whether or not patients are able to return to athletic activity
following
This study investigated the effects of transcatheter arterial embolization (TAE) on pain, function, and quality of life in people with early-stage symptomatic knee osteoarthritis (OA) compared to a sham procedure. A total of 59 participants with symptomatic Kellgren-Lawrence grade 2 knee OA were randomly allocated to TAE or a sham procedure. The intervention group underwent TAE of one or more genicular arteries. The control group received a blinded sham procedure. The primary outcome was knee pain at 12 months according to the Knee injury and Osteoarthritis Outcome Score (KOOS) pain scale. Secondary outcomes included self-reported function and quality of life (KOOS, EuroQol five-dimension five-level questionnaire (EQ-5D-5L)), self-reported Global Change, six-minute walk test, 30-second chair stand test, and adverse events. Subgroup analyses compared participants who received complete embolization of all genicular arteries (as distinct from embolization of some arteries) (n = 17) with the control group (n = 29) for KOOS and Global Change scores at 12 months. Continuous variables were analyzed with quantile regression, adjusting for baseline scores. Dichotomized variables were analyzed with chi-squared tests.Aims
Methods
Body exhaust suits or surgical helmet systems (colloquially, ‘space suits’) are frequently used in many forms of arthroplasty, with the aim of providing personal protection to surgeons and, perhaps, reducing periprosthetic joint infections, although this has not consistently been borne out in systematic reviews and registry studies. To date, no large-scale study has investigated whether this is applicable to shoulder arthroplasty. We used the New Zealand Joint Registry to assess whether the use of surgical helmet systems was associated with lower all-cause revision or revision for deep infection in primary shoulder arthroplasties. We analyzed 16,000 shoulder arthroplasties (hemiarthroplasties, anatomical, and reverse geometry prostheses) recorded on the New Zealand Joint Registry from its inception in 2000 to the present day. We assessed patient factors including age, BMI, sex, and American Society of Anesthesiologists (ASA) grade, as well as whether or not the operation took place in a laminar flow operating theatre.Aims
Methods
Total hip and knee arthroplasty (THA, TKA) are largely successful procedures; however, both have variable outcomes, resulting in some patients being dissatisfied with the outcome. Surgeons are turning to technologies such as robotic-assisted surgery in an attempt to improve outcomes. Robust studies are needed to find out if these innovations are really benefitting patients. The Robotic Arthroplasty Clinical and Cost Effectiveness Randomised Controlled Trials (RACER) trials are multicentre, patient-blinded randomized controlled trials. The patients have primary osteoarthritis of the hip or knee. The operation is Mako-assisted THA or TKA and the control groups have operations using conventional instruments. The primary clinical outcome is the Forgotten Joint Score at 12 months, and there is a built-in analysis of cost-effectiveness. Secondary outcomes include early pain, the alignment of the components, and medium- to long-term outcomes. This annotation outlines the need to assess these technologies and discusses the design and challenges when conducting such trials, including surgical workflows, isolating the effect of the operation, blinding, and assessing the learning curve. Finally, the future of robotic surgery is discussed, including the need to contemporaneously introduce and evaluate such technologies. Cite this article:
Objectives. The Oxford Hip and Knee Scores (OHS, OKS) have been demonstrated
to vary according to age and gender, making it difficult to compare
results in cohorts with different demographics. The aim of this
paper was to calculate reference values for different patient groups
and highlight the concept of normative reference data to contextualise an
individual’s outcome. Methods. We accessed prospectively collected OHS and OKS data for patients
undergoing
Knee osteoarthritis (OA) is characterized by a chronic inflammatory process involving multiple cytokine pathways, leading to articular cartilage degeneration. Intra-articular therapies using pharmaceutical or autologous anti-inflammatory factors offer potential non-surgical treatment options. Autologous protein solution (APS) is one such product that uses the patient’s blood to produce a concentrate of cells and anti-inflammatory cytokines. This study evaluated the effect of a specific APS intra-articular injection (nSTRIDE) on patient-reported outcome measures compared to saline in moderate knee OA. A parallel, double-blinded, placebo-controlled randomized controlled trial was conducted, where patients with unilateral moderate knee OA (Kellgren-Lawrence grade 2 or 3) received either nSTRIDE or saline (placebo) injection to their symptomatic knee. The primary outcome was the difference in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score at 12 months post-intervention. Secondary outcomes included WOMAC component scores, Knee injury and Osteoarthritis Outcome Score (KOOS), and visual analogue scale (VAS) scores at all follow-up timepoints (three, six, and 12 months).Aims
Methods
Satisfaction with care is important to both patients
and to those who pay for it. The Net Promoter Score (NPS), widely
used in the service industries, has been introduced into the NHS
as the ‘friends and family test’; an overarching measure of patient
satisfaction. It assesses the likelihood of the patient recommending
the healthcare received to another, and is seen as a discriminator
of healthcare performance. We prospectively assessed 6186 individuals
undergoing primary
Structural scoliosis occurs more commonly in patients with juvenile chronic arthritis than in the normal population. We have reviewed 32 patients with both juvenile arthritis and a scoliosis and suggest that structural curves may arise from postural curves associated with asymmetrical involvement of
Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement. We recruited nine participants with cam and/or pincer morphologies and with pain, 13 participants with cam and/or pincer morphologies and without pain, and 11 controls from a population-based cohort. We scanned hips in active squatting and passive sitting flexion, adduction, and internal rotation using open MRI and quantified anterior femoroacetabular clearance using the β angle.Aims
Methods
We reviewed the outcome in 24 children with bilateral spastic cerebral palsy aged seven years or younger for whom surgery was recommended between 1999 and 2005 following gait analysis. A total of 13 children (operative group) had surgery and the remaining 11 (control group) did not, for family or administrative reasons. The operative group had at least two post-operative gait analyses at yearly intervals, with eight children having a third and six children a fourth. The control group had a second analysis after a mean interval of 1.5 years (95% confidence interval 1.1 to 1.9). In the operative group, the Gillette gait index, the ranges of movement in the
The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively. A per protocol analysis of 76 patients, 43 of whom underwent TKA and 34 of whom underwent bi-UKA, was performed from a prospective, single-centre, randomized controlled trial. Diaries kept by the patients recorded pain, function, and the use of analgesics daily throughout the first week and weekly between the second and sixth weeks. Patient-reported outcome measures (PROMs) were compared preoperatively, and at three months and one year postoperatively. Data were also compared longitudinally and a subgroup analysis was conducted, stratified by preoperative PROM status.Aims
Methods
Evaluating musculoskeletal conditions of the lower limb and understanding the pathophysiology of complex bone kinematics is challenging. Static images do not take into account the dynamic component of relative bone motion and muscle activation. Fluoroscopy and dynamic MRI have important limitations. Dynamic CT (4D-CT) is an emerging alternative that combines high spatial and temporal resolution, with an increased availability in clinical practice. 4D-CT allows simultaneous visualization of bone morphology and joint kinematics. This unique combination makes it an ideal tool to evaluate functional disorders of the musculoskeletal system. In the lower limb, 4D-CT has been used to diagnose femoroacetabular impingement, patellofemoral, ankle and subtalar joint instability, or reduced range of motion. 4D-CT has also been used to demonstrate the effect of surgery, mainly on patellar instability. 4D-CT will need further research and validation before it can be widely used in clinical practice. We believe, however, it is here to stay, and will become a reference in the diagnosis of lower limb conditions and the evaluation of treatment options. Cite this article:
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
Osteonecrosis (ON) can cause considerable morbidity in young people who undergo treatment for acute lymphoblastic leukaemia (ALL). The aims of this study were to determine the operations undertaken for ON in this population in the UK, along with the timing of these operations and any sequential procedures that are used in different joints. We also explored the outcomes of those patients treated by core decompression (CD), and compared this with conservative management, in both the pre- or post-collapse stages of ON. UK treatment centres were contacted to obtain details regarding surgical interventions and long-term outcomes for patients who were treated for ALL and who developed ON in UKALL 2003 (the national leukaemia study which recruited patients aged 1 to 24 years at diagnosis of ALL between 2003 and 2011). Imaging of patients with ON affecting the femoral head was requested and was used to score all lesions, with subsequent imaging used to determine the final grade. Kaplan-Meier failure time plots were used to compare the use of CD with non surgical management.Aims
Methods
The aim of this study is to test the hypothesis that three grades of sagittal compensation for standing posture (normal, compensated, and decompensated) correlate with health-related quality of life measurements (HRQOL). A total of 50 healthy volunteers (normal), 100 patients with single-level lumbar degenerative spondylolisthesis (LDS), and 70 patients with adult to elderly spinal deformity (deformity) were enrolled. Following collection of demographic data and HRQOL measured by the Scoliosis Research Society-22r (SRS-22r), radiological measurement by the biplanar slot-scanning full body stereoradiography (EOS) system was performed simultaneously with force-plate measurements to obtain whole body sagittal alignment parameters. These parameters included the offset between the centre of the acoustic meatus and the gravity line (CAM-GL), saggital vertical axis (SVA), T1 pelvic angle (TPA), McGregor slope, C2-7 lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, sacral slope (SS), pelvic tilt (PT), and knee flexion. Whole spine MRI examination was also performed. Cluster analysis of the SRS-22r scores in the pooled data was performed to classify the subjects into three groups according to the HRQOL, and alignment parameters were then compared among the three cluster groups.Aims
Methods
To date, no study has demonstrated an improvement in postoperative outcomes following elective joint arthroplasty with a focus on nutritional intervention for patients with preoperative hypoalbuminaemia. In this prospective study, we evaluated differences in the hospital length of stay (LOS), rate of re-admission, and total patient charges for a malnourished patient study population who received a specific nutrition protocol before surgery. An analytical report was extracted from the electronic medical record (EMR; Epic, Verona, Wisconsin) of a five-hospital network joint arthroplasty patient data set between 2014 and 2017. A total of 4733 patients underwent joint arthroplasty and had preoperative measurement of albumin levels: 2220 at four hospitals and 2513 at the study hospital. Albumin ≤ 3.4 g/l, designated as malnutrition, was found in 543 patients (11.5%). A nutritional intervention programme focusing on a high-protein, anti-inflammatory diet was initiated in January 2017 at one study hospital. Hospital LOS, re-admission rate, and 90-day charges were compared for differential change between patients in study and control hospitals for all elective hip and knee arthroplasty patients, and for malnourished patients over time as the nutrition intervention was implemented.Aims
Patients and Methods
There is little information regarding the risk of a patient developing prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) when the patient has previously experienced PJI of a TKA or total hip arthroplasty (THA) in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population against matched controls. We retrospectively reviewed 95 patients (102 primary TKAs) treated between 2000 and 2014 with a history of PJI in another TKA or THA. A total of 50 patients (53%) were female. Mean age was 69 years (45 to 88) with a mean body mass index (BMI) of 36 kg/m2 (22 to 59). In total, 27% of patients were on chronic antibiotic suppression. Mean follow-up was six years (2 to 16). We 1:3 matched these (for age, sex, BMI, and surgical year) to 306 primary TKAs performed in 306 patients with a THA or TKA of another joint without a subsequent PJI. Competing risk with death was used for statistical analysis. Multivariate analysis was followed to evaluate risk factors for PJI in the study cohort.Aims
Patients and Methods
The aims of this study were to analyse the long-term outcome
of vascularised fibular graft (VFG) reconstruction after tumour
resection and to evaluate the usefulness of the method. We retrospectively reviewed 49 patients who had undergone resection
of a sarcoma and reconstruction using a VFG between 1988 and 2015.
Their mean follow-up was 98 months (5 to 317). Reconstruction was
with an osteochondral graft (n = 13), intercalary graft (n = 12),
inlay graft (n = 4), or resection arthrodesis (n = 20). We analysed
the oncological and functional outcome, and the rate of bony union
and complications.Aims
Patients and Methods
Osteoarthritis (OA) is the most common form of arthritis, affecting approximately 15% of the human population. Recently, increased concentration of nitric oxide in serum and synovial fluid in patients with OA has been observed. However, the exact role of nitric oxide in the initiation of OA has not been elucidated. The aim of the present study was to investigate the role of nitric oxide in innate immune regulation during OA initiation in rats. Rat OA was induced by performing meniscectomy surgery while cartilage samples were collected 0, 7, and 14 days after surgery. Cartilage cytokine levels were determined by using enzyme-linked immunosorbent assay, while other proteins were assessed by using Western blotObjectives
Methods
The February 2014 Knee Roundup360 looks at: whether sham surgery is as good as arthroscopic meniscectomy; distraction in knee osteoarthritis; whether trans-tibial tunnel placement increases the risk of graft failure in ACL surgery; whether joint replacements prevent cardiac events; the size of the pulmonary embolism problem; tranexamic acid and knee replacement haemostasis; matching the demand for knee replacement and follow-up; predicting the length of stay after knee replacement; and popliteal artery injury in TKR.
The aim of this study was to define return to
theatre (RTT) rates for elective hip and knee replacement (HR and
KR), to describe the predictors and to show the variations in risk-adjusted
rates by surgical team and hospital using national English hospital
administrative data. We examined information on 260 206 HRs and 315 249 KRs undertaken
between April 2007 and March 2012. The 90-day RTT rates were 2.1%
for HR and 1.8% for KR. Male gender, obesity, diabetes and several
other comorbidities were associated with higher odds for both index
procedures. For HR, hip resurfacing had half the odds of cement fixation
(OR = 0.58, 95% confidence intervals (CI) 0.47 to 0.71). For KR,
unicondylar KR had half the odds of total replacement (OR = 0.49,
95% CI 0.42 to 0.56), and younger ages had higher odds (OR = 2.23,
95% CI 1.65 to 3.01) for ages <
40 years compared with ages 60
to 69 years). There were more funnel plot outliers at three standard deviations
than would be expected if variation occurred on a random basis. Hierarchical modelling showed that three-quarters of the variation
between surgeons for HR and over half the variation between surgeons
for KR are not explained by the hospital they operated at or by
available patient factors. We conclude that 90-day RTT rate may
be a useful quality indicator for orthopaedics. Cite this article:
We have recently shown that waste heat from forced-air
warming blankets can increase the temperature and concentration
of airborne particles over the surgical site. The mechanism for
the increased concentration of particles and their site of origin
remained unclear. We therefore attempted to visualise the airflow
in theatre over a simulated total knee replacement using neutral-buoyancy
helium bubbles. Particles were created using a Rocket PS23 smoke
machine positioned below the operating table, a potential area of
contamination. The same theatre set-up, warming devices and controls
were used as in our previous study. This demonstrated that waste
heat from the poorly insulated forced-air warming blanket increased
the air temperature on the surgical side of the drape by >
5°C.
This created convection currents that rose against the downward
unidirectional airflow, causing turbulence over the patient. The
convection currents increased the particle concentration 1000-fold
(2 174 000 particles/m3 for forced-air warming Cite this article:
We examined the risk of thrombotic and major
bleeding events in patients undergoing total hip and knee replacement
(THR and TKR) treated with thromboprophylaxis, using nationwide
population-based databases. We identified 83 756 primary procedures
performed between 1997 and 2011. The outcomes were symptomatic venous thromboembolism
(VTE), myocardial infarction (MI), stroke, death and major bleeding
requiring hospitalisation within 90 days of surgery. A total of 1114 (1.3%) and 483 (0.6%) patients experienced VTE
and bleeding, respectively. The annual risk of VTE varied between
0.9% and 1.6%, and of bleeding between 0.4% and 0.8%. The risk of
VTE and bleeding was unchanged over a 15-year period. A total of
0.7% of patients died within 90 days, with a decrease from 1% in
1997 to 0.6% in 2011 (p <
0.001). A high level of comorbidity
and general anaesthesia were strong risk factors for both VTE and
bleeding, with no difference between THR and TKR patients. The risk
of both MI and stroke was 0.5%, which remained unchanged during
the study period. In this cohort study of patients undergoing THR and TKR patients
in routine clinical practice, approximately 3% experienced VTE,
MI, stroke or bleeding. These risks did not decline during the 15-year
study period, but the risk of dying fell substantially. Cite this article:
We hypothesised that the use of computer navigation-assisted
surgery for pelvic and sacral tumours would reduce the risk of an
intralesional margin. We reviewed 31 patients (18 men and 13 women)
with a mean age of 52.9 years (13.5 to 77.2) in whom computer navigation-assisted
surgery had been carried out for a bone tumour of the pelvis or
sacrum. There were 23 primary malignant bone tumours, four metastatic
tumours and four locally advanced primary tumours of the rectum.
The registration error when using computer navigation was <
1 mm
in each case. There were no complications related to the navigation,
which allowed the preservation of sacral nerve roots (n = 13), resection
of otherwise inoperable disease (n = 4) and the avoidance of hindquarter
amputation (n = 3). The intralesional resection rate for primary
tumours of the pelvis and sacrum was 8.7% (n = 2): clear bone resection
margins were achieved in all cases. At a mean follow-up of 13.1
months (3 to 34) three patients (13%) had developed a local recurrence.
The mean time alive from diagnosis was 16.8 months (4 to 48). Computer navigation-assisted surgery is safe and has reduced
our intralesional resection rate for primary tumours of the pelvis
and sacrum. We recommend this technique as being worthy of further
consideration for this group of patients. Cite this article:
We investigated the incidence of and risk factors
for venous thromboembolism (VTE) following surgery of the shoulder
and elbow and assessed the role of thromboprophylaxis in upper limb
surgery. All papers describing VTE after shoulder and elbow surgery
published in the English language literature before 31 March 2012
were reviewed. A total of 14 papers were available for analysis,
most of which were retrospective studies and case series. The incidence
of VTE was 0.038% from 92 440 shoulder arthroscopic procedures,
0.52% from 42 261 shoulder replacements, and 0.64% from 4833 procedures
for fractures of the proximal humerus (open reduction and internal fixation
or hemiarthroplasty). The incidence following replacement of the
elbow was 0.26% from 2701 procedures. Diabetes mellitus, rheumatoid
arthritis and ischaemic heart disease were identified as the major
risk factors. The evidence that exists on thromboprophylaxis is based on level
III and IV studies, and we therefore cannot make any recommendations
on prophylaxis based on the current evidence. It seems reasonable
to adopt a multimodal approach that involves all patients receiving
mechanical prophylaxis, with chemical prophylaxis reserved for those
who are at high risk for VTE. Cite this article:
This study compared the demographic, clinical and patient-reported outcomes after total hip replacement (THR) and Birmingham Hip Resurfacing (BHR) carried out by a single surgeon. Patients completed a questionnaire that included the WOMAC, SF-36 scores and comorbid medical conditions. Data were collected before operation and one year after. The outcome scores were adjusted for age, gender, comorbid conditions and, at one year, for the pre-operative scores. There were 214 patients with a THR and 132 with a BHR. Patients with a BHR were significantly younger (49 vs 67 years, p <
0.0001), more likely to be male (68% vs 42% of THR, p <
0.0001) and had fewer comorbid conditions (1.3 vs 2.0, p <
0.0001). Before operation there was no difference in WOMAC and SF-36 scores, except for function, in which patients awaiting THR were worse than those awaiting a BHR. At one year patients with a BHR reported significantly better WOMAC pain scores (p = 0.04) and in all SF-36 domains (p <
0.05). Patients undergoing BHR report a significantly greater improvement in general health compared with those with a THR.
We undertook a randomised controlled trial to compare the outcomes of skin adhesive and staples for skin closure in total hip replacement. The primary outcome was the cosmetic appearance of the scar at three months using a surgeon-rated visual analogue scale. In all, 90 patients were randomised to skin closure using either skin adhesive (n = 45) or staples (n = 45). Data on demographics, surgical details, infection and oozing were collected during the in-patient stay. Further data on complications, patient satisfaction and evaluation of cosmesis were collected at three-month follow-up, and a photograph of the scar was taken. An orthopaedic and a plastic surgeon independently evaluated the cosmetic appearance of the scars from the photographs. No significant difference was found between groups in the cosmetic appearance of scars at three months (p = 0.172), the occurrence of complications (p = 0.3), or patient satisfaction (p = 0.42). Staples were quicker and easier to use than skin adhesive and also less expensive. Skin adhesive and surgical staples are both effective skin closure methods in total hip 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.