The Hospital (Trust) guidelines generally recommend 40mg of Low molecular weight heparin (LMWH) twice daily (BD) for all patients over 100kg for those undergoing total hip (THR) and knee replacements (TKR) respectively. British National Formulary (BNF) recommends 40mg of LMWH once daily (OD) for all patients regardless of their overall weight or body mass index (BMI). We evaluated the outcome of prophylactic LMWH dosage for patients undergoing THR and TKR by monitoring surgery related venous-thromboembolic events up to a minimum of three months after surgery. A retrospective audit was carried out after obtaining institutional approval and all consecutive elective patients weighing over 100kg and undergoing THR and TKR were included. All patients were followed up for a minimum of 3 months after their operation to investigate the dose of prophylactic LMWH received, and whether they had developed any venous thromboembolic events (VTE) post operatively. This was done using a combination of electronic notes, drug charts and deep venous thrombosis (DVT) or computed tomography pulmonary angiogram (CTPA) reports on the hospital/trust database. A total of 53 patients underwent elective THR (18) and TKR (35) between the period of March 2017 and September 2017. Forty-four patients received 40 mg OD and 9 patients had 40 mg BD. None of the patients developed a confirmed DVT or pulmonary embolism in the 3 months following surgery regardless of the dose received. We demonstrate that there is no clinical benefit in having patients over 100kg on twice daily LMWH with the aim of preventing post-op thromboembolic complications. This conclusion is in line with the BNF recommendations for VTE prophylaxis

Thrombin has many biological properties similar to those of growth factors. In a previous study, we showed that thrombin improves healing of the rat tendo Achillis. Low molecular weight heparin (LMWH) inhibits the activity and the generation of thrombin. We therefore considered that LMWH at a thromboprophylactic dose might inhibit tendon repair. Transection of the tendo Achillis was carried out in 86 rats and the healing tested mechanically. Low molecular weight heparin (dalateparin) was either injected a few minutes before the operation and then given continuously with an osmotic mini pump for seven days, or given as one injection before the operation. In another experiment ,we gave LMWH or a placebo by injection twice daily. The anti-factor Xa activity was analysed. Continuous treatment with LMWH impaired tendon healing. After seven days, this treatment caused a 33% reduction in force at failure, a 20% reduction in stiffness and a 67% reduction in energy uptake. However, if injected twice daily, LMWH had no effect on tendon healing. Anti-factor Xa activity was increased by LMWH treatment, but was normal between intermittent injections. Low molecular weight heparin delays tendon repair if given continuously, but not if injected intermittently, probably because the anti-factor Xa activity between injections returns to normal, allowing sufficient thrombin stimulation for repair. These findings indicate the need for caution in the assessment of long-acting thrombin and factor Xa inhibitors

Aim. Thromboprophylaxis in total hip replacement (THR) and total knee replacement (TKR) remains controversial, conspicuous by absence of consensus. Because of protracted and variable mobilisation, there is an extended risk of Venous Thromboembolism (VTE). We hypothesised that a combination of low molecular weight heparin and miniwarfarin would minimise the initial and extended risk. Therefore we evolved a protocol of enoxaparin sodium 40 mgs for 5 days starting preoperatively and miniwarfarin 1-2mg for 6 weeks following surgery. We undertook a retrospective study of total hip and knee replacements in a District General Hospital between January 2000 and December 2005 to determine the effectiveness of the protocol. Methods. We analysed the incidence of symptomatic VTE in 1307 patients, of who 681 underwent THR and 626 TKR. We evaluated the incidence of symptomatic DVT and PE between 0-6 weeks, 6 weeks-3months and 3-6 months following surgery. Results. Total incidence of VTE in the study group as a whole including both total hip and knee arthroplasty in 6 months following surgery was 29/1307 (2.22%), after THR 12/681 (1.76%) and after TKR 17/626 (2.72%). VTE at 6 weeks following TKR was 12/626 (1.92%) and THR 4/681(0.59%); between 6 weeks-3 months following TKR 1/626 (0.16%) and THR 6/681 (0.88%); between 3- 6 months 4/626 (0.64%) following TKR and 2/681 (0.29%) after THR. DVT following TKR was 12/626 (1.92%) at 6 months and following THR 7/681 (1.03%). PE at 6 months after TKR was 5/626 (0.80%) and THR 5/681(0.73%) with no attributable mortality. Conclusions. The incidence of VTE using our thromboprophylaxis protocol - low molecular weight heparin (LMWH) and very low dose warfarin - in THR and TKR not only compares favourably with other modes of thrombo-prophylaxis in literature, but also is cheap and cost effective

In a prospective study of 205 consecutive patients undergoing surgical stabilisation of acute pelvic and/or acetabular fractures, the incidence of proximal deep vein thrombosis (DVT) was 9.2%, pulmonary embolism (PE) was 1.9% and fatal PE 0.5%. Use of a DVT prophylaxis protocol, using a low molecular weight heparin (LMWH), administered within 24 hours of injury or achieving haemodynamic stability, was associated with a significantly lower incidence of thromboembolism (p=0.036). Increased rates of thromboembolism were associated with longer delays to surgery (p=0.013), delays to mobilisation of the patient post-operatively (p=0.017), delay in starting chemoprophylaxis (p=0.039) and higher injury severity scores (p=0.042). Patient age, sex, Glasgow Coma Scale and fracture classification were not associated with the development of thromboembolic complications. One hundred and thirty four patients had a pre-operative venous Doppler, seven patients had a proximal DVT identified of which six patients had a preoperative inferior vena caval filter applied and underwent successful surgical fracture stabilisation. Five filters were unable to be removed postoperatively and the patients remain on lifelong warfarin. A DVT prophylaxis protocol using LMWH is reported that is safe and effective

There is little in the recent literature about the place of low molecular weight heparin (LMWH) in routine lumbosacral surgery. This study aimed to determine firstly the risk of deep vein thrombosis (DVT) if Clexane was not given preoperatively, and secondly the complications associated with the use of the drug. In a prospective study undertaken from January 2001 to April 2001, 64 patients scheduled for routine lumbosacral surgery were entered. We excluded patients with a high risk of DVT. The mean age of patients was 51 years (16 to 75). Patients were randomly selected to receive Endoxaparin (Clexane) preoperatively the night before (38 patients in group 1) or Clexane postoperatively (26 patients in group. 2). All patients were evaluated by Doppler sonography pre-operatively, four days postoperatively and at six weeks. Blood loss was monitored intra-operatively and postoperatively. Clexane was administered only for eight days. Posterior lumbosacral spinal procedures only were done on 44 patients, while seven had combined anterior-posterior surgery and 13 anterior procedures only. Mean intra-operative and postoperative blood losses in group 1 were twice those in group 2, and patients in group 1 tended to bleed for longer. Two cases of partial thrombosis were seen, both group 1. In group 1 intraspinal haematoma formation was seen in four patients, two of whom required additional surgery. LMWH should not be given preoperatively for routine spinal cases. In fact, it is contra-indicated

Purpose: The report of a case o f a patient, who underwent a total hip arthroplasty and sustained cerebral hemorrhage due to low molecular weight heparin. Case report: A 46-years-old woman had a total hip replacement due to secondary osteoarthritis after a congenital hip dislocation. She had a free medical record. Treatment with LMWH started the day of the surgery. The patient was dismissed from the hospital the sixth postoperative day, being well, and came back the ninth postoperative day, complaining of hypertension, headache and motor disturbances of her left upper limb. Neurological examination did not revealed any particular findings except reduced strength of her left upper limb. A brain CT scanning showed no significant findings, while her blood platelet count was126000 while immediately postoperatively was 180000 and preoperatively 220000. The following day the patient established a paresis of her left arm and the platelet count fell to 35000, while a new CT scan, revealed small hemorrhages in both parietal cortexes of the brain. LMWH was discontinued. The patient deceased the 11th postoperative day. Conclusion: Heparin Induced Thrombocytopenia type II and hemorrhage due to LMWH is very rare but should be bared in mind from the orthopaedic surgeon who uses LMWH for DVT prophylaxis. Clinical suspicion mandates immediate discontinuation of the agent and consideration of an alternative anticoagulation therapy along with general support of the patient

Low molecular weight heparin (LMWH) is frequently used as thromboprophylaxis after major orthopaedic surgery. Varying levels of non-adherence (5% to 45%) with outpatient LMWH has been reported. Oral direct thrombin inhibitors have been recommended by industry due to ease of administration. We aim to audit the compliance rate with outpatient LMWH treatment following primary total hip arthroplasties (THA) in our district general hospital (DGH). Using the ORMIS computer system, we identified all primary THA performed in Monklands Hospital between July 2011 and August 2012. Patients’ case notes were analysed retrospectively, looking at operating surgeon's postoperative thromboprophylaxis instructions. We then conducted a telephone interview on patients discharged with outpatient LMWH to assess compliance. There were 58 primary THAs performed during the audit period. 33 patients were discharged on outpatient LMWH, whilst 15 patients and 3 patients were discharged on aspirin and warfarin respectively. Seven patients were excluded as their discharge prescriptions were missing. We successfully contacted 20 of the 33 patients discharged with outpatient LMWH. All respondents showed 100% compliance to the full course of treatment. 50% of patients self-administered; 30% were administered by district nurses and 20% by family members. 35% of patients preferred an oral tablet alternative, for its perceived ease of administration. Bruising and skin irritation were the reported problems in some patients, but these did not affect compliance. Contrary to the previous published non-adherence rates, the compliance rate with outpatient LMWH after THA was high in our DGH. The patient counseling, and family/district nurse involvement in may have contributed to this. However, our numbers of patients are low but data collection continues

Introduction. The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use. Methods. Through the orthopaedic clinical directors forum, Trusts replacing LMWH with Rivaroxaban for lower limb arthroplasty thromboprophylaxis during 2009 were identified. Prospectively collected Hospital episode statistics (HES) data was then analysed for these units so as to determine rates of 90-day symptomatic deep venous thrombosis (DVT), pulmonary thromboembolism (PTE), major bleed (cerebrovascular accident or gastrointestinal haemorrhage), all-cause mortality, and 30-day wound infection and readmission rates before and after the change to Rivaroxaban. 2752 patients prescribed Rivaroxaban following TKR or THR were compared to 10358 patients prescribed LMWH. Data was analysed using odds ratios (OR). Results. There were significantly more wound infections in the Rivaroxaban group (3.85% vs. 2.81%, OR=0.72; 95% CI 0.58-0.90). There were no significant differences between the two groups for PTE (OR=1.52; 0.77-2.97), major bleed (OR=0.73; 0.48-1.12), all-cause mortality (OR=0.93; 0.46-1.87) and re-admission rate (OR=1.21; 0.88-1.67). There were significantly fewer symptomatic DVTs in the Rivaroxaban group (0.91% vs. 0.36%, OR=2.51; 1.30-4.82). Conclusion. This study is the first to describe the real impact of the use of Rivaroxaban in the NHS. When compared with LMWH in lower limb arthroplasty patients, wound infection rates were significantly higher following Rivaroxaban use whilst providing no reduction in symptomatic PTE or all-cause mortality

Background. The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use. Methods. Through the orthopaedic clinical directors forum, Trusts replacing LMWH with Rivaroxaban for lower limb arthroplasty thromboprophylaxis during 2009 were identified. Prospectively collected Hospital episode statistics (HES) data was then analysed for these units so as to determine rates of 90-day symptomatic deep venous thrombosis (DVT), pulmonary embolism (PE), major bleed (cerebrovascular accident or gastrointestinal haemorrhage), all-cause mortality, and 30-day wound infection and readmission rates before and after the change to Rivaroxaban. 2752 patients prescribed Rivaroxaban following TKR or THR were compared to 10358 patients prescribed LMWH. Data was analysed using odds ratios (OR). Results. There were significantly more wound infections in the Rivaroxaban group (3.85% vs. 2.81%, OR=0.72; 95% CI 0.58–0.90). There were no significant differences between the two groups for PE (OR=1.52; 0.77–2.97), major bleed (OR=0.73; 0.48–1.12), all-cause mortality (OR=0.93; 0.46–1.87) and re-admission rate (OR=1.21; 0.88–1.67). There were significantly fewer symptomatic DVTs in the Rivaroxaban group (0.91% vs. 0.36%, OR=2.51; 1.30–4.82). Discussion. This study is the first to describe the real impact of the use of Rivaroxaban in the NHS. When compared with LMWH in lower limb arthroplasty patients, there were fewer DVTs in the Rivaroxaban group. However, wound infection rates were significantly higher following Rivaroxaban use whilst providing no reduction in symptomatic PE or all-cause mortality

The purpose of the present study is to determine the incidence, location and rate of VTE following routine mechanical, chemical prophylaxis in trauma/elective patients and to understand what factors are responsible for the continuing high frequency of thromboembolic complication despite the fact that low molecular-weight heparin (LMWH) is now widely used for prophylaxis.

All of the inpatients at the orthopaedics ward, Princess Alexandra Hospital (level one trauma centre, Brisbane) between the first May 2009 and 30th of April 2010 with the diagnosis of DVT/PE were included in this study. Patients were chosen based on the diagnosis of DVT with ultrasound or PE with CTPA during their admission in this period which was performed whenever clinical signs indicated DVT or PE.

64% of the included patients had DVT and 42% had PE which was developed during their admission. Included patients had a mean age ±SD age of 56years ± 23 years, 68% were men and 72% suffered trauma. The 18% of patients had previous history of PE or DVT. The incidence of VTE was significantly higher in men at ages between 20–40 .29% of the patients had ICU admission during their stay in hospital. 28%had spinal cord injury, 21%with head trauma, and 36%with multiple bone fractures. Most of the patients had lower limb injury or operation and just one patient was with isolated upper limb injury. The mean period of hospitalization for the included patients were 29 ± 19 days (range, 6–77). DVTs occurred 8 days ± 7 days(range, 1–31) post admission. PEs occurred 10 days ± 8 days (range, 3–30) after admission. Location of DVT was available for 14 patients: 9 (64%)lower and 6 (43 %)upper, with one(0.07%)having both. Twelve of 28 patients with VTE were started on prophylactic clexane (40mg once daily), and six patients were on heparin(5000 unit twice daily). All of the patients with PE had lower limb injury.

Considering the number of orthopaedics ward patients during our study period our data show the incidence of VTE in one year is lower than that of literature and the common standard prophylaxis with early mechanical prophylaxis after admission and following pharmacological prophylaxis when it is safe has acceptable results.

Study design: In order to evaluate a new CECT (Continuous Enhanced Circulation Therapy) based on protocol for DVT prevention a prospective, randomize, single-blind study was designed to compare the effect of the new protocol to the current standard of care in DCT prophylaxis (LMWH).

Objectives: To evaluate and compare the incidence and severity of DVT between the two groups.

Background: Total hip and knee replacements are operations particularly prone to thromboembolic complications. Recommendations regarding prophylaxis have changed over the years. A treatment protocol was proposed, based upon the CECT system as the primary DVT prophylaxis method with the addition of low dose aspirin. This protocol is using two very safe treatment modalities with very low risk for adverse effects. The CECT system applies continuous mechanical enhancement of venous blood flow through a miniature, mobile, battery operated system.

Methods: 39 patients, who underwent total hip or knee replacement, were prospectively randomized into two groups. In the study group the patients received CECT system starting immediately after the induction of anesthesia and covering the operation and the first 5 postoperative days, within 12 hours after surgery aspirin 100 mg per day was added. In the control group the patients received Enoxaparin 40 mg per day for 5 postoperative days. A venography was performed at the 5th to 8th post-operative day and the DVT prevalence was compared.

Results: In the study group 3 patients out of 21 (14.3%) were found to have DVT (1 of them proximal), compared to 8 patients out of 18 (44.4%) in the control group (5 of them proximal). The differences between the two groups are statistically significant for both total and proximal DVT rates (p=0.037).

In the study group only 1 patient needed prolonged high dose anticoagulant treatment while 6 patients in the enoxaparin group were treated (p=0.020).

The cumulative incidence of adverse events in the study group was significantly lower than that observed in the control group (p=0.000). Average postoperative hospital stay was 8.4 days in the study group and 11.7 days in the control group (p=0.002).

The CECT device was very well tolerated by the patients and facilitated early mobilization.

Conclusions: The protocol combining CECT and Aspirin was found to be both safe the effective. Comparison to the standard prophylaxis with enoxaparin revealed significant advantage of the proposed protocol with: better DVT prevention, less adverse events and shorter hospital stay. Further research is needed in order to establish the place of this prophylaxis protocol as the treatment of choice in orthopaedic patients.

The incidence of deep-vein thrombosis and the need for thromboprophylaxis following isolated trauma below the knee is uncertain. We have investigated this with a prospective randomised double-blind controlled trial using low molecular weight heparin with saline injection as placebo in patients aged between 18 and 75 years who had sustained an isolated fracture below the knee which required operative fixation. All patients had surgery within 48 hours of injury and were randomised to receive either the placebo or low molecular weight heparin for 14 days, after which they underwent bilateral lower limb venography, interpreted by three independent radiologists. Further follow-up was undertaken at two, six, eight and 12 weeks. A total of 238 patients fulfilled all the inclusion criteria, with 127 in the low molecular weight heparin group and 111 in the placebo group, all of whom underwent bilateral venography. There was no statistically significant difference in the incidence of deep-vein thrombosis between those patients treated with low molecular weight heparin or the placebo (p = 0.22). The number of deep-vein thromboses in the two groups was 11 (8.7%) and 14 (12.6%), respectively. Age and the type of fracture were significantly associated with the rate of deep-vein thrombosis (p = 0.001 and p = 0.009, respectively) but gender, comorbidities and the body mass index were not. The overall incidence of deep-vein thrombosis in this series was 11%. There was no clinical or statistical significant reduction in the incidence of deep-vein thrombosis with the use of thromboprophylaxis. However, we accept that owing to a cessation of funding, recruitment to this trial had to be ended prior to establishing the necessary sample size. Our results cannot, therefore, categorically exclude the possibility that low molecular weight heparin treatment could be beneficial. We recommend a further multicentre trial be undertaken to resolve this matter

Venous Thromboembolism is a common complication following a hip replacement. Recently the pulmonary embolism prevention study was published. It reported that aspirin decreased the fatal pulmonary embolism rate in patients admitted with a fracture neck of femur. In addition new products (synthetic factor X inhibitor -Fondaparinux, and a direct thrombin inhibiter-Desirudin) have been reported to be more effective than low molecular weight heparin in preventing asymptomatic deep vein thrombosis. We felt it was important to repeat a survey, done in 1997, on the use thromboembolism prophylaxis among British Orthopaedic Surgeons. A single page questionnaire was sent out to all 1308 consultants Orthopaedic surgeons who were members of the British Orthopaedic Association. Those who did not respond were sent a reminder letter. We achieved a 72% response rate. All surgeons use some form of prophylaxis. Eighty five percent of surgeons use pharmacological prophylaxis. Low molecular weight heparin is used by 55% of surgeons. Twenty percent of surgeons use aspirin as their only form of pharmacological prophylaxis. Less than 1% (5 consultants) use early mobilisation alone and nearly 2% (13 consultants) use graded stockings and early mobilisation as their only form of prophylaxis. Seventy four percent of surgeons have a unit policy. Thirty percent have changed their regime in the last 3 years. The majority of British Orthopaedic surgeons still use pharmacological thromboprophylaxis. There has been a significant increase in the use of Aspirin from 5% to 30%. Aspirin is often combined with a mechanical prophylaxis. This has led to an increase in the use of intermittent calf compression (3% to 22%), and foot pumps (12% to 19%). Low molecular weight heparin use has fallen by 10%. The majority of British Orthopaedic surgeons still use pharmacological thromboprophylaxis. There has been a significant increase in the use of Aspirin from 5% to 30%. Aspirin is often combined with a mechanical prophylaxis. This has led to an increase in the use of intermittent calf compression (3% to 22%), and foot pumps (12% to 19%). Low molecular weight heparin use has fallen by 10%

Introduction and Aims: Venous Thromboembolism is a common complication following a hip replacement. Recently the pulmonary embolism prevention study was published. It reported that aspirin decreased the fatal pulmonary embolism rate in patients admitted with a fracture neck of femur. In addition, new products (synthetic factor X inhibitor-Fondaparinux, and a direct thrombin inhibiter-Desirudin) have been reported to be more effective than low molecular weight heparin in preventing asymptomatic deep vein thrombosis. We felt it was important to repeat a survey, done in 1997, on the use of thromboembolism prophylaxis among British Orthopaedic Surgeons. Method: A single page questionnaire was sent out to all 1308 consultants – orthopaedic surgeons who were members of the British Orthopaedic Association. Those who did not respond were sent a reminder letter. Results: We achieved a 72% response rate. All surgeons use some form of prophylaxis. Eighty-five percent of surgeons use pharmacological prophylaxis. Low molecular weight heparin is used by 55% of surgeons. Twenty percent of surgeons use aspirin as their only form of pharmacological prophylaxis. Less than 1% (five consultants) use early mobilisation alone and nearly 2% (13 consultants) use graded stockings and early mobilisation as their only form of prophylaxis. Seventy-four percent of surgeons have a unit policy. Thirty percent have changed their regime in the last three years. Conclusion: The majority of British orthopaedic surgeons still use pharmacological thromboprophylaxis. There has been a significant increase in the use of Aspirin, from 5% to 30%. Aspirin is often combined with a mechanical prophylaxis. This has led to an increase in the use of intermittent calf compression (3% to 22%), and foot pumps (12% to 19%). Low molecular weight heparin use has fallen by 10%

The National Institute for Clinical Excellence, UK published guidelines in 2007 encouraging the use of low molecular weight heparin (LMWH) joint replacement surgery. Subsequently, our hospital adopted these guidelines in the treatment of total hip replacements. This study is based on our prospective database of total hip replacements between 2005 and 2009 and compares the complication and mortality rates pre- and post institution of the NICE guidelines. We analysed prospectively collected data on 686 patients who underwent a primary total hip replacement done by a single surgeon between January 2005 and April 2009. We compared the incidence of mortality, pulmonary embolism, myocardial infarction and intracranial bleeding between the two groups. Prior to the guidelines, all patients were treated for the duration of their admission with 75mg aspirin followed by 4 weeks after discharge. Subsequent to the guidelines, the treatment changed to 40mg of LMWH (Clexane) while an inpatient with aspirin being prescribed for 4 weeks on discharge. Patients unable to tolerate aspirin were treated with low molecular weight heparin. High risk patients (previous pulmonary embolism, previous deep vein thrombosis, family history) were treated with 6 weeks of warfarin. Each patients was reviewed at 8 weeks and 6 months following surgery, and adverse incidents were documented at each review or incident. Results: 686 patients were identified from the study – 328 pre and 358 post implementation of the NICE guidelines. In the pre-guideline group the mortality was 0.6%, with the incidence of pulmonary embolism being 0.3%, myocardial infarction 0.9% and intracranial bleed 0.3%. Both complications of myocardial infarction occurred early in the post-operative stage and were fatal. The post-guideline group had a mortality rate of 0.2%, with the incidence of pulmonary embolism being 0.2% and intracranial bleeding 0.2%. No myocardial infarctions were noted in this group. The single death was as a result of an intracranial bleed. The was no significant statistical difference in the incidence of mortality, pulmonary embolism, myocardial infarction or intracranial bleeding between the two groups (p value > 0.05, 95% confidence interval). There were no complications in the warfarinised patients of which there were equal numbers in both groups (16). Conclusion: This study has shown that the change in thromboprophylaxis has not had a significant effect on complication rates in primary total hip replacements and that our mortality rate (0.4%) compares favourably with recent literature. The lack of complications in the war-farinised group probably reflects that high risk patients were identified in the screening process and commenced on warfarin early in the post operative period. Note must be made of the single death due to an intracranial bleed while on low molecular weight heparin

Purpose. This study investigates the effect of early tourniquet release on range of flexion following total knee replacement, and the influence of anticoagulation with Rivaroxaban and Clexane (Enoxaparin). Method. 78 patients were included in the study, who underwent unilateral primary total knee replacement (TKR) in our department under the care of two specialist knee surgeons over a 12 month period. 27 patients underwent TKR with early release of the tourniquet and haemostasis, prior to closure of quadriceps layer: 22 were anticoagulated with Rivaroxaban (GROUP ER), 15 with the low molecular weight heparin Clexane (GROUP EC). Over the same time period, 41 patients TKR with late release of the tourniquet, following closure and bandaging: 13 were anticoagulated with Rivaroxaban (GROUP LR), 28 with Clexane (GROUP LC). A standardised operative technique was employed, and all patients received an AGC (Biomet) PCL-retaining prostheses. Outcome was assessed with range of flexion at 12 weeks postoperatively. Results. The mean range of flexion at 12 weeks was 106.8° in Group ER, 96.54° in Group LR, 108.33° in Group EC and 101.11° in LC. The mean difference in flexion at 12 weeks between Group EC and LC was 7.2°, and between ER and LR was 10.2°. Conclusion. Our study supports the theory that early tourniquet release and haemostasis has a beneficial effect on the early range of flexion following TKR. This affect appears to be increased when the oral anticoagulant Rivaroxaban is used, when compared with low molecular weight heparin

Abstract. Introduction. Neck of femur (NOF) fracture patients are at risk of developing venous thromboembolisms (VTE). VTE risks could be reduced by adhering to the National Institute for Health and Care Excellence (NICE) recommendation for 1 month of prophylaxis with low molecular weight heparin. This audit aimed to assess and improve local compliance to national guidelines on VTE prophylaxis in NOF fracture patients following discharge. Methods. A retrospective consecutive case series of all NOF fractures treated at our institution from May – July 2021 was conducted. Those not eligible for outpatient VTE prophylaxis were excluded (anticoagulated for other indications, completed prophylactic course in hospital, inpatient death, pharmacological prophylaxis contraindicated). The agent and duration of VTE prophylaxis, and the occurrence of clinically significant VTE or bleeds were recorded. A re-audit was conducted in March 2022. Results. From May – July 2021, only 1/65 (1.5%) patient was discharged on a VTE prophylaxis regime consistent with NICE guidelines (1 enoxaparin, 56 rivaroxaban, 6 apixaban; 58 35-day course, 5 28-day course). A quick-guide document summarising the standard inpatient and outpatient VTE prophylaxis regimes for various orthopaedic indications was designed and widely disseminated. In March 2022, 30/34 (88.2%) patients were discharged with enoxaparin and 24/34 (70.6%) received a 28-day course. There were no cases of clinically significant VTE or bleeds in both cycles. Conclusion. Local compliance to national guidelines improved significantly with the implementation of a standardised VTE prophylaxis protocol. Our quick-guide document is a reproducible way of communicating consensus and ensuring consistency within a department

Total Joint Arthroplasty (TJA) is a successful orthopaedic procedure allowing dramatic clinical and functional improvements. Globally, there's been an increase in demand and performed cases associated with an increase in complications. Subsequently, focus on the prevention of complications has become important worldwide. The incidence of venous-thrombolic events (VTE) despite great attention has not diminished despite much investigation. A balance between efficacy and safety from the available agents is essential. Low molecular weight heparin (LMWH) has been commonly used, but oral anti-coagulants have become more popular. The aim of this study was to assess the adherence LMWH and the effectiveness and safety of preventing VTE in post-operative arthroplasty patients in a South African setting. We conducted a prospective cohort study that included hip and knee, primary and revision, arthroplasty patients who received thromboprophylaxis with one daily injection of LMWH for 14 days post discharge. Patients who omitted 1 or more doses during the follow up period were classified as “non adherent”. A questionnaire was used at follow up visits at least 6 weeks post-operatively. 100 consecutive patients were followed up. The mean age of patients was 63.45 years. There were 68 % female patients. There was a 92% compliance rate. 60 % of patients had the injection administered by a family member, 38 % administered it themselves and 2 % had the injection administered by health professionals. Venous thromboembolic events were confirmed in 5 % at 7.86 days after surgery. Three patients had persistent wound drainage after surgery, however, none required reoperation or readmission. Compliance with LMWH is high and is comparable with oral agents. It is effective in preventing VTE and safe with regards to bleeding and wound complications in a South African setting. Patient education regarding medications may improve compliance of the medication

Postoperative leg swelling after a total knee replacement is common complaint amongst patients. We studied leg swelling by constructing a novel, simple and cost water volumeter. A pilot study was conducted on 15 volunteers by two observers and each observer took a total of three readings. The mean intraobserver variation was 0.2 percent and mean interobserver variation was 0.3 percent, indicating a highly acceptable level of accuracy. The water volumeterwas then used in a randomized prospective study was conducted to determine the relationship between postoperative leg swelling and Fraxiparine, a low molecular weight heparin. From the period of 1st January 2000 till 31th October 2000, a total of 36 patients were enrolled in the study. 18 patients in the study group received fraxiparine and 18 patients in the control group did not. The leg volume was measured preoperatively and on postoperative days 5, 7 and 10. We found that both groups developed maximum swelling at postoperative day 5 and this decreased to almost normal at day 10. However the fraxiparine group was statistically less swollen (4%) than the control group (10%) on day 5 and also on day 7 (−0.2% vs 7%). These findings were independent of whether the patient underwent bilateral or unilateral surgery. We conclude that low molecular weight heparins are effective in reducing postoperative leg swelling in total knee replacement

Background: Aetiology of venous thromboembolism is multifactorial and thromboprophylaxis includes mechanical and chemical agents. There is no clear consensus on the choice of chemical agent in elective total hip arthroplasty (THA), although National Institute of Clinical Excellence (NICE) recommends low molecular weight heparin or fondaparinux to all patients. Aim: The aim of our study was to define the efficacy and safety of various chemical agents currently used for venous throboprophylaxis – namely aspirin, warfarin and low molecular weight heparin in primary THA. Methods: We retrospectively reviewed 905 consecutive patients with primary THA during an 18 month period. Medical notes were reviewed to record demographic data, inpatient and outpatient thromboprophylactic agents, total hospital stay, readmission, incidence of DVT, pulmonary embolism and death following surgery. Post-operative mobility, transfusion requirements and complications were noted. Suspected thromboembolic events were investigated with venous Doppler ultrasound scanning and CTPA. Results: 417 (46%) patients received aspirin, 253 received enoxaparin, 190 patients had low dose warfarin and 45 patients had none or multiple agents for inpatient thromboprophylaxis. 615 patients had cemented and 290 patients received uncemented total hip arthroplasty. Patients predominantly received aspirin (61%) as outpatient prophylactic agent. 41 patients were investigated for a suspected thromboembolic event. 2 patients had DVT and 2 patients had PE. There were 3 deaths within 6 weeks, one each due to PE, sepsis and unknown cause. All 4 patients with thromboembolism were on enoxaparin for prophylaxis. Conclusion: In our study aspirin was the preferred choice for thromboprophylaxis following total hip arthroplasty. We found that aspirin was most effective with no complications and enoxaparin was least effective. We advise the use of aspirin as the first choice drug for thromboprophylaxis as reiterated by some recent studies

Introduction: Currently patients who had undergone lower limb arthroplasty are discharged a few days after surgery, at which stage they still need anticoagulation treatment. The transition from hospital to the community is a sensitive period and is susceptible to mistakes and misunderstandings. Patients may underestimate the importance of the continuing treatment and their inconvenience to self-administrate subcutaneous treatment might decrease their compliance. The purpose of this prospective cohort study was to investigate the continuity of the treatment with subcutaneous low molecular weight heparin at the transition period from the hospital to the community. Materials and Methods: 209 consecutive consenting patients who had undergone lower limb arthroplasty were recruited. Ten were excluded from the study since they were subscribed oral anticoagulation; 4 patients developed pulmonary embolism and were not included, and 8 patients were lost to follow up. 187 patients were followed weekly by phone and were asked about their adherence to the daily treatment, about clinical signs suggesting a thromboembolic event and whether they sought medical assistance. Three months later there was another clinical follow up. Results: Of the 187 patients, 174 (93%; 95% CI 88.9% < p < 96.4%) were compliant. The percentage of doctor visits by TKR patients was statistically significantly higher, (p=0.007) than by THR patients. There was no significant difference in the compliance of patients who live with their families and patients who live alone. Patients with 0–6 years of education tend to search medical advice statistically significantly more (p=0.004) than patients with more than 7 years of education. Discussion: The rate of compliance to anticoagulation treatment with subcutaneous low molecular weight heparin was encouraging. It demonstrates that the patients understand the necessity and importance of the treatment

We report an audit of 208 patients with a mean age of 39 years (16 to 65) attending the Orthopaedic Assessment Unit at the Wellington Hospital between January 2006 and December 2007 with an injury of the tendo Achillis requiring immobilisation in a cast. Information on assessment of venous thromboembolism (VTE) risk, prophylactic measures and VTE events for all patients was obtained from the medical records. A VTE risk factor was documented in the records of three (1%) patients. One of the 208 patients received aspirin prophylaxis; none received low molecular weight heparin. In all, 13 patients (6.3%, 95% confidence interval 3.4 to 10.5) developed symptomatic VTE during immobilisation in a cast, including six with a distal deep-vein thrombosis (DVT), four with a proximal DVT, and three with a confirmed pulmonary embolus. This incidence of symptomatic VTE is similar to that reported following elective hip replacement. We propose that consideration is given to VTE prophylaxis during prolonged immobilisation of the lower limbs in a cast, to ensure that the same level of protection is provided as for patients undergoing elective hip replacement

Thromboprophylaxis after elective orthopaedic surgery remains controversial. Recent guidelines from the National Institute for Clinical Excellence (NICE) have suggested that low molecular weight heparin should be given to all patients undergoing total hip replacement. The British Orthopaedic Association is currently debating this guideline with NICE, as it is not clear whether published evidence supports this view. We present the early mortality in our unit after total hip replacement using aspirin as chemical thromboprophylaxis. The 30-day and 90-day mortality after primary total hip arthroplasty was zero. We compare this with that reported previously from our unit without using chemical thromboprophylaxis. With the introduction of routine aspirin thromboprophylaxis, deaths from cardiovascular causes have dropped from 0.75% to zero. These results demonstrate that there is a strong argument for the routine administration of aspirin after elective total hip replacement

Thrombelastography (TEG) is a point-of-care tool that can measure clot formation and breakdown using a whole blood sample. We have previously used serial TEG analysis to define hypercoagulability and increased venous thromboembolism (VTE) risk following a major fracture requiring surgical treatment. Additionally, we have used serial TEG analysis to quantify the prolonged hypercoagulable state and increased VTE risk that ensues following a hip fracture. Recently developed cartridge-based platelet mapping (PLM) using TEG analysis can be used to activate platelets at either the adenosine diphosphate (ADP) receptor or at the Thromboxane A2 (AA) receptor, in order to evaluate clot strength when platelets are activated only through those specific receptors. This study aim was to evaluate platelet contribution to hypercoagulability, in order to identify potential therapeutic targets for VTE prevention. We hypothesized that there would be a platelet-predominant contribution to hypercoagulability following a hip fracture. Patients aged 50 years or older with a hip fracture treated surgically were enrolled in this prospective cohort study. Exclusion criteria were: prior history of VTE, active malignancy, or pre-injury therapeutic dose anticoagulation. Serial TEG and PLM analyses were performed at admission, post-operative day (POD) 1, 3, 5, 7 and at 2-, 4-, 6- and 12-weeks post-operatively. All patients received thromboprophylaxis with low molecular weight heparin (LMWH) for 28 days post-operatively. Hypercoagulability was defined as maximal amplitude (MA; a measure of clot strength) over 65mm based on TEG analysis. Independent samples t-tests were used to compare MA values with this previously established threshold and a mixed effects linear regression model was used to compare MA values over time. Independent samples t-tests and Chi-sqaured analyses were used to compare between the surgical fixation and arthroplasty groups. Forty-six patients with an acute hip fracture were included, with a mean age of 77.1 (SD = 10.6) years, with 61% (N=11) being female. Twenty-six were treated with arthroplasty (56.5%), while the remainder underwent surgical fixation of their hip fractures. TEG analysis demonstrated post-operative hypercoagulability (mean MA over 65mm) at all follow-up timepoints until 12-weeks. PLM identified a platelet-mediated hypercoagulable state based on elevated ADP-MA and AA-MA, with more pronounced platelet contribution demonstrated by the AA pathway. Patients treated with arthroplasty had significantly increased AA-MA compared with ADP-MA at POD 3 and at the 12-week follow-up. Thrombelastography can be used to identify hypercoagulability and increased risk for VTE following a hip fracture. Platelet mapping analysis from this pilot study suggests a platelet-mediated hypercoagulable state that may benefit from thromboprophylaxis using an anti-platelet agent that specifically targets the AA platelet activation pathway, such as acetylsalicylic acid (ASA). This research also supports differences in hypercoagulability between patients treated with arthroplasty compared to those who undergo fracture fixation

Introduction. The use of intramedullary lengthening devices is becoming increasingly popular. There are no published data regarding the incidence of venous thromboembolism following intramedullary lengthening and no reports or guidance for current practices on use of thromboprophylaxis. Following a case of post-operative deep vein thrombosis in our institution, we felt that it is important to assess best practice. We conducted this survey to collect data that would describe current practice and help guide consensus for treatment. Materials and Methods. We have identified surgeons across the UK that perform intramedullary lengthening through the British Limb Reconstruction Society membership and a Precise Users database. Surgeons were contacted and asked to respond to an online survey (SurveyMonkey - SVMK Inc.). Responses to thromboprophylaxis regimes employed in their practice and cases of venous thromboembolism were collated. Results. 24 out of 54 surgeons identified responded with a total of 454 cases of intramedullary lengthening (352 femoral and 102 tibial nails) performed over the last 5 years. Only one case of DVT following femoral lengthening was reported. There is wide variability in practice both in terms of thromboprophylaxis risk assessment, choice of medications (20% no pharmacological treatment, 75% Low molecular Weight Heparin, 5% Aspirin) and duration of treatment (0–42 days). The vast majority of surgeons (85%) felt that there was insufficient evidence available to guide their practice. Conclusions. Intramedullary lengthening is a relatively recent and novel surgical treatment. As a result there is limited data available to guide decision making regarding aspects of treatment such as thromboprophylaxis. This is reflected in the wide variation in practice reported in this study. There is both a need and a desire to gather data that will allow us to come to a consensus and to guide safe practice

Major orthopaedic fractures are an independent risk factor for the development of venous thromboembolism (VTE), which are significant causes of preventable morbidity and mortality in trauma patients. Despite thromboprophylaxis, patients who sustain a pelvic or acetabular fracture (PA) continue to have high rates of VTE (12% incidence). Thrombelastography (TEG) is a whole-blood, point-of-care test which provides an overview of the clotting process. Maximal amplitude (MA), from TEG analysis, is the measure of clot strength and values ≥65mm have been used to quantify hypercoagulability and increased VTE risk. Therefore, the primary aim was to use serial TEG analysis to quantify the duration of hypercoagulability, following surgically treated PA fractures. This is a single centre, prospective cohort study of adult patients 18 years or older with surgically treated PA fractures. Consecutive patients were enrolled from a Level I trauma centre and blood draws were taken over a 3-month follow-up period for serial TEG analysis. Hypercoagulability was defined as MA ≥65mm. Exclusion criteria: bleeding disorders, active malignancy, current therapeutic anticoagulation, burns (>20% of body surface) and currently, or expecting to become pregnant within study timeframe. Serial TEG analysis was performed using a TEG6s hemostasis analyzer (Haemonetics Corp.) upon admission, pre-operatively, on post-operative day (POD) 1, 3, 5, 7 (or until discharged from hospital, whichever comes sooner), then in follow-up at 2-, 4-, 6-weeks and 3-months post-operatively. Patients received standardized thromboprophylaxis with low molecular weight heparin for 28 days post-operatively. VTE was defined as symptomatic DVT or PE, or asymptomatic proximal DVT, and all participants underwent a screening post-operative lower extremity Doppler ultrasound on POD3. Descriptive statistics were used to determine the association between VTE events and MA values. For the primary outcome measure, the difference between the MA threshold value (≥65mm) and serial MA measures, were compared using one-sided t-tests (α=0.05). Twenty-eight patients (eight females, 29%) with a mean age of 48±18 years were included. Acetabular fractures were sustained by 13 patients (46%), pelvic fractures by 14 patients (50%), and one patient sustained both. On POD1, seven patients (25%) were hypercoagulable, with 21 patients (78%) being hypercoagulable by POD3, and 17 patients (85%) by POD5. The highest average MA values (71.7±3.9mm) occurred on POD7, where eight patients (89%) were hypercoagulable. At 2-weeks post-operatively, 16 patients (94%) were hypercoagulable, and at four weeks, when thromboprophylaxis was discontinued, six patients (40%) remained hypercoagulable. Hypercoagulability persisted for five patients (25%) at 6-weeks and for two patients (10%) by three months. There were six objectively diagnosed VTE events (21.4%), five were symptomatic, with a mean MA value of 69.3mm±4.3mm at the time of diagnosis. Of the VTE events, four occurred in participants with acetabular fractures (three male, 75%) and two in those with pelvic fractures (both males). At 4-weeks post-operatively, when thromboprophylaxis is discontinued, 40% of patients remained hypercoagulable and likely at increased risk for VTE. At 3-months post-operatively, 10% of the cohort continued to be hypercoagulable. Serial TEG analysis warrants further study to help predict VTE risk and to inform clinical recommendations following PA fractures

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

Venous thromboembolism (VTE) is a serious complication after total hip and knee arthroplasty. There is still no consensus regarding the best mode of thromboprophylaxis after lower limb arthroplasty. The aim of this study was to ascertain the efficacy, safety profile and rate of adverse thromboembolic events of aspirin as extended out of hospital pharmacological anticoagulation for elective primary total hip and knee arthroplasty patients and whether these rates were comparable with published data for low molecular weight heparin (LMWH). Data was extracted from a prospective hospital acquired thromboembolism (HAT) database. The period of study was from 1st Jan 2013-31st Dec 2016 and a total of 6078 patients were treated with aspirin as extended thromboprophylaxis after primary total hip and knee arthroplasty. The primary outcome measure of deep vein thrombosis and pulmonary embolism within 90 days postoperatively was 1.11%. The secondary outcome rates of wound infection, bleeding complications, readmission rate and mortality were comparable to published results after LMWH use. The results of this study clearly show that Aspirin, as part of a multimodal thromboprophylactic regime, is an effective and safe regime in preventing VTE with respect to risk of DVT or PE when compared to LMWH. It is a cheaper alternative to LMWH and has associated potential cost savings

Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower-limb arthroplasty. However, trials supporting its use have not fully evaluated the risks of wound complications. This study of 1048 total hip/knee replacements records the rates of return to theatre and infection before and after the change from a low molecular weight heparin (tinzaparin) to rivaroxaban as the agent of chemical thromboprophylaxis in patients undergoing lower-limb arthroplasty. During a period of 13 months, 489 consecutive patients undergoing lower-limb arthroplasty received tinzaparin and the next 559 consecutive patients received rivaroxaban as thromboprophylaxis. Nine patients in the control (tinzaparin) group (1.8%, 95% confidence interval 0.9 to 3.5) returned to theatre with wound complications within 30 days, compared with 22 patients in the rivaroxaban group (3.94%, 95% confidence interval 2.6 to 5.9). This increase was statistically significant (p = 0.046). The proportion of patients who returned to theatre and became infected remained similar (p = 0.10). Our study demonstrates the need for further randomised controlled clinical trials to be conducted to assess the safety and efficacy of rivaroxaban in clinical practice, focusing on the surgical complications as well as the potential prevention of venous thromboembolism

Introduction. Deep venous thrombosis (DVT) is a potentially serious complication after total hip (THA) and knee (TKA) arthroplasty, traditionally justifying aggressive prophylaxis with low molecular weight heparin (LMWH) or direct oral anticoagulants (DOA) at the cost of an increased risk of bleeding. However, fast-track procedures might reduce the DVT risk and decrease the cost-benefit ratio of the current recommendations. The objective of this study was to compare thrombotic and bleeding risk in an unselected population of elective THA and TKA with a fast-track procedure. MATERIAL - METHODS. A series of 1,949 patients were analyzed prospectively. There were 1,136 women and 813 men, with a mean age of 70 years. In particular, 16% were previously treated by antiplatelet agents and 8% by anticoagulants. All patients followed a fast-track procedure including early walking within 24 hours of surgery, and 80% of patients returned home after surgery, with a mean length of stay of 3 days (THA) or 4 days (TKA). The occurrence of a thromboembolic event or hemorrhagic complication has been identified. Results. Out of the 1,110 THAs, 5 thromboembolic events were identified (0.4%): 2 non-fatal pulmonary embolism and 3 DVTs. There was no impact of these complications on the final result. 19 hemorrhagic complications were identified (1.7%): 10 significant haematomas (3 of which were complicated by infection), 9 anemias (with 4 transfusions). Out of the 839 TKAs, 9 thromboembolic events were identified (1.0%): 4 non-fatal pulmonary embolism and 5 DVTs. There was no impact of these complications on the final result. 14 hemorrhagic complications were identified (1.7%): 8 haematomas including 4 reoperations, 6 anemias (with 5 transfusions). Discussion. Thromboembolic complications after elective THA and TKA have virtually disappeared, with a rate of 0.7%. On the other hand, bleeding complications are now more frequent, with a rate of 1.7%. This suggests that the cost-benefit ratio of preventive treatments with LMWH or DOA should be reassessed. Prescribing LMWH or DOA after elective THA and TKA with fast-track procedures exposes the patient to a much higher risk of bleeding than thrombotic risk. The use of aspirin may represent an acceptable compromise in these patients

A randomized trial was designed to compare the outcome of ceramic-on-ceramic with ceramic on conventional polyethylene. These patients have been followed for 15 years. 58 hips in 57 patients under 60 years of age were randomized into one of two groups. Patients were blinded to the type of hip they received. Both groups of patients were treated routinely with prophylactic peri-operative antibiotics and low molecular weight Heparin. All patients were seen at six weeks, three months and annually after surgery. Clinical and radiologic assessment was carried out at each visit. Fifty-eight hips were available for analysis, 28 in the CoP group and 29 patients in the CoC group. Mean age of both groups was less than 45 years. There were seven revisions (16%) among the 58 patients enrolled in the study. In the CoP group four patients underwent revision with head and liner exchange for eccentric polyethylene wear 16 years post-implantation. In the CoC group one patient had a cup revision at 15 years for acute aseptic instability of the acetabulum; two additional patients in the CoC group had femoral head exchange, one for fracture and one for trunnion corrosion. Both occurred 14 years after the index surgery. Functional outcome scores showed no difference between the two groups at 15 years. Radiographically there was a statistically difference in wear between the two groups. This study demonstrates that both ceramic-on-ceramic and ceramic-on-polyethylene produce satisfactory functional results with low revision rates in young patients

Aims. 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. Materials and Methods. 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. Results. Evidence from one good quality randomised controlled trial (RCT) showed no difference in rates of venous thrombo-embolism (VTE) in patients given aspirin or low molecular weight heparin (LMWH) following TKA. There was insufficient evidence from trials with moderate to severe risk of bias being present to suggest aspirin is more or less effective than LMWH, warfarin or dabigatran for the prevention of VTE in TKA or THA. Compared with aspirin, rates of asymptomatic deep vein thrombosis (DVT) in TKA may be reduced with rivaroxaban but insufficient evidence exists to demonstrate an effect on incidence of symptomatic DVT. Compared with aspirin there is evidence of more wound complications following THA and TKA with dabigatran and in TKA with rivaroxaban. Some studies highlighted concerns over bleeding complications and efficacy of aspirin. Conclusion. The results suggest aspirin may be considered a suitable alternative to other thromboprophylactic agents following THA and TKA. Further investigation is required to fully evaluate the safety and efficacy of aspirin. Cite this article: Bone Joint J 2016;98-B:1056–61

Venous thromboembolism (VTE) prophylaxis following total joint arthroplasty (TJA) should be individualised in order to maximise the efficacy of prophylactic measures while avoiding the adverse events associated with the use of anticoagulants. At our institution, we have developed a scoring model using the Nationwide Inpatient Sample (NIS) database, which is validated against our institutional data, to stratify patients into low- and high-risk groups for VTE. Low-risk patients are placed on aspirin 81 mg twice daily for four weeks post-operatively, and high-risk patients are placed on either a Vitamin K antagonist (warfarin), low molecular weight heparin, or other oral anticoagulants for four weeks post-operatively. All patients receive sequential pneumatic compression devices post-operatively, and patients are mobilised with physical therapy on the day of surgery. Patients who have a history of peptic ulcer disease or allergy to aspirin are also considered for other types of anticoagulation following surgery. Risk Stratification Criteria. Major comorbid risk factors utilised in our risk stratification model include history of hypercoagulability or previous VTE, active cancer or history of non-cutaneous malignancy, history of stroke, and pulmonary hypertension. We consider patients with any of these risk factors at elevated risk of VTE and therefore candidates for formal anticoagulation. Other minor risk factors include older age, bilateral surgery compared with unilateral, inflammatory bowel disease, varicose veins, obstructive sleep apnea, and history of myocardial infarction, myeloproliferative disorders, and congestive heart failure. Each minor criterion is associated with a score. The cumulative score is compared with a defined threshold and the score that surpasses the threshold indicates that the patient should receive post-operative anticoagulation. To facilitate the use of this scoring system, an iOS mobile application (VTEstimator) has been developed and can be downloaded from the app store

According to the National Institute of Clinical Excellence (NICE) Guidelines, some foot and ankle patients are, by definition, at high risk of DVT/PE. Despite NICE guidance, DVT recommendations are still controversial, and are being reviewed by the BOA to be more operation and context specific. One consultant at our institution therefore initiated a 6 week medical DVT prophylaxis regimen for all his post-operative hind–foot surgery patients who were placed in plaster. From January 2007 to February 2008 we audited 97 hind-foot patients to measure their compliance rate, complications and DVT/PE rate. Compliance was excellent (97%) particularly with regard to Low Molecular Weight Heparin (LMWH), but only 70% had medication prescribed for the 6 weeks, and 3% developed a DVT. Self administered LMWH is acceptable and compliance is excellent in post operative orthopaedic patients, but not necessarily effective

We studied 4253 patients undergoing primary joint replacement between November 2002 and November 2007, of whom 4060 received aspirin only as chemical prophylaxis; 46 were mistakenly given low molecular weight heparin initially, which was stopped and changed to aspirin; 136 received no chemoprophylaxis and 11 patients received warfarin because of a previous history of pulmonary embolism. We identified the rate of clinical thromboembolism before and after discharge, and the mortality from pulmonary embolism at 90 days. The overall death rate was 0.31% (13 of 4253) and the rate of fatal pulmonary embolism was 0.07% (3 of 4253). Our data suggest that fatal pulmonary embolism is not common following elective primary joint replacement, and with modern surgical practice elective hip and knee replacement should no longer be considered high-risk procedures

Surgery for pelvic or acetabular fractures carries a high risk of deep-vein thrombosis (DVT). Reports indicate that fondaparinux is a more effective thromboprophylactic agent than low molecular weight heparin (LMWH) after major orthopaedic surgery. We prospectively evaluated a new protocol for DVT prophylaxis using fondaparinux. Patients and methods. One hundred and eight patients with pelvic or acetabular fractures were randomised to receive either fondaparinux or enoxaparin. Specific review points included the primary end-point of clinical deep vein thrombosis (DVT) or pulmonary embolism (PE) and any evidence of adverse effects such as bleeding or allergic reactions. Results. Two patients that received enoxaparin were found to have a DVT (3%) and one patient died from a PE (1%). There was no documented DVT or PE in patients that received fondaparinux. The mean number of units of blood transfused was significantly higher in the enoxaparin group and this was significant post-operatively (p<0.05). The current study supports that post-operative fondaparinux, in patients with pelvic and acetabular fractures, is more effective and equally safe to enoxaparin

Aims. The place of thromboprophylaxis in arthroplasty surgery remains controversial, with a challenging requirement to balance prevention of potentially fatal venous thrombo-embolism with minimising wound-related complications leading to deep infection. We compared the incidence of fatal pulmonary embolism in patients undergoing elective primary total hip arthroplasty (THA) between those receiving aspirin, warfarin and low molecular weight heparin (LMWH) for the chemical component of a multi-modal thromboprophylaxis regime. Patients and Methods. A prospective audit database was used to identify patients who had died within 42 and 90 days of surgery respectively between April 2000 and December 2012. A case note review was performed to ascertain the causes of death. Results. During this period 7983 THAs were performed. The rate of mortality was 0.43% and 0.58% at 42 and 90 days respectively. The groups comprised 1571 patients (19.7%) on warfarin, 1838 (23.0%) on LMWH and 4574 (57.3%) on aspirin. The 90-day mortality for these three groups was 0.38%, 1.09% and 0.43% respectively. The higher mortality rate for LMWH was significant (p < 0.05). There were six fatal pulmonary emboli (PEs) (0.08%). A total of three occurred within 42 days, all in the LMWH group. A total of three occurred between 42 and 90 days; one on warfarin, two on LMWH. The leading causes of death in all three groups were lower respiratory tract infections and myocardial infarction. Conclusion. We confirmed that fatal PE following elective THA with a multi-modal prophylaxis regime is rare. We further found that LMWH conferred no benefit over aspirin in this context, and is associated with a higher all-cause rate of mortality. Take home message: This study proposes that aspirin may be an appropriate thromboprophylaxis agent when used as part of a multi-modal regimen, suggesting current guidelines should be reviewed. Cite this article: Bone Joint J 2016;98-B:585–8

Introduction: Thromboprophylaxis in Orthopaedic practice has long been a debated issue. The recent NICE guidelines have recommended low molecular weight heparins (LMWH) for all orthopaedic patients, although a number of authors have highlighted the low risk of thromboembolism in foot and ankle practice. We looked at our series of total ankle replacements (TAR) to identify the incidence of thromboembolism and any complications associated with chemical thromboprophylaxis. Methods: All patients who had undergone TAR were reviewed retrospectively. Risk factors according to the NICE guidelines were identified as was the type of chemical thromboprophylaxis, if given. Complications including thromboembolism, wound ooze, swelling and delay in discharge were recorded. Results: There were 45 TAR’s in 45 patients. 20 patients (44%) had been given some form of chemical thromboprophylaxis. There were no cases of thromboembolism in either group. In the group receiving chemical thromboprophylaxis, nine patients (45%) had a wound complication. In the group receiving no chemical thromboprophylaxis only one patient (4%) had a wound complication. Discussion: Thromboprophylaxis in total ankle replacement may significantly increase the risk of wound complications. We would recommend caution when prescribing chemical prophylaxis for patients undergoing total ankle replacement

National Institute for Clinical Excellence (NICE) guidelines on venous thromboembolic (VTE) prophylaxis for patients undergoing orthopaedic surgery recommend that all inpatients be offered a low molecular weight heparin (LMWH). Linked hospital episode statistics of 219602 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. This was compared with data from the National Joint Register (England and Wales) regarding LMWH usage during the same periods. There was a significant increase in the reported use of LMWH (59.5 to 67.6%, p< 0.01) between the two periods. However, 90-day VTE events increased following both total hip (THR, 1.67% to 1.84%, p=0.06) and knee replacement (TKR, 1.99% to 2.04%, p=0.60). 30-day return to theatre rate for infection fell following TKR, but increased after THR. In addition, there were increases in rates of thrombocytopenia, which was significant following THR (p=0.03). Recommendations from NICE are based on predicted reductions in VTE events, reducing morbidity, mortality and costs to the National Health Service. Early results in orthopaedic patients are unable to support these predictions

According to the 2004 ACCP guidelines on antithrombotic and thrombolytic therapy general extended prophylaxis with low molecular weight heparins, vitamin K antagonists, or fondaparinux is recommended after major orthopedic surgery. This recommendation is based on a number of placebo controlled, clinical studies using venographic screening for deep vein thrombosis (DVT), as a surrogate end-point for pulmonary embolism (PE), other vascular thrombotic events were not considered. In a recent meta-analysis on these studies the overall event rate of symptomatic venous thromboembolism 30–42 days after a joint arthroplasty was 2.7% DVT and 0.6 % PE in patients having short-term prophylaxis and it was significantly reduced by extended prophylaxis. Bleeding episodes were seen in 4% of cases having extension. Taking into consideration the risk benefit for the individual patient do these findings justify that extended prophylaxis is used on a general basis? To answer this question also compliance, adverse event profile, and cost of the prophylactic regimens have to be addressed. It would be very attractive to be able to individualize the duration of the prophylactic period by assessing the thrombotic potential of every patient in order to balance the risks and benefits of continued prophylaxis

Introduction. We investigated the incidence of venous thromboembolism (VTE) and pulmonary embolism (PE) after total knee arthroplasty (TKA) and assessed the efficacy and complications of three different chemical prophylactic regimens. Materials and Methods. From May, 2011 to November 2013, 268 patients, 330 knees were randomly allocated to three groups, low molecular weight heparin (LMWH) 5000IU for 2 days followed by aspirin 100mg for 5 days (Group HA, 110 knees), rivaroxaban 10mg for 7 days (Group X7, 110 knees), or for 10 days (Group X10, 110 knees) postoperatively. Intermittent pneumatic compression device was applied on all patients. The multidetector row computed tomography (MDCT) was done at postoperative 10 days to evaluate VTE (PE & DVT separately), and MDCT was rechecked to evaluate the changes of VTE at postoperative 3 months in VTE patients. Additionally, major and minor bleeding complications, amounts of bleeding, and bruise around wound were checked. Results. The incidence of VTE was 42 (38.2%) in Group HA, 22 (20.0%) in Group X7, 11 (10.0%) in Group X10. Deep vein thrombosis (DVT) was revealed 39 (35.5%) in Group HA, 17 (15.5%) in Group X7, 8 (7.3%) in Group X10. Group HA showed statistically higher prevalence in VTE and DVT than rivaroxavan groups. PE was detected 21 (19.1%) in Group HA, 11 (10.0%) in Group X7, 3 (2.7%) in Group X10. Group X10 was statistically significantly lower PE incidence than Group HA (p=0.0001) and Group X7 (p=0.027). Asymptomatic distal DVT was completely resolved in 88.8% with no specific treatment. There was no major or minor bleeding complications and bleeding amounts were not statistically different in 3 groups. Conclusion. Rivaroxaban has better prophylactic efficacy with no increasing bleeding complications than LMWH followed by aspirin. Ten days rivaroxaban was more effective for PE and VTE prevention than 7 days rivaroxavan. However, most of reduced VTEs were asymptomatic and distal DVTs

Despite increasing scientific investigation, the best method for preventing post-operative deep vein thrombosis remains unclear in patients undergoing a total hip replacement. In the wake of the recent controversial National Institute for Health and Clinical Excellence Clinical Guidelines on the prevention of thrombo-embolism, we felt it was timely to survey current Scottish Surgeons thrombo-prophylactic practice when performing total hip replacements. E-mail questionnaires were sent to all Scottish Orthopaedic consultants. They were asked about routine pharmacological and mechanical prophylaxis in patients undergoing total hip replacement. Comparison was made with a previous survey done in 2003. The response rate was 75%. The survey showed an increased use of pharmacological prophylaxis from 93% to 100%. This was due to the increased use of aspirin, from 51% to 64%. The use of Low molecular weight heparin had remained the same at 51%. No surgeons routinely use Warfarin, low dose heparin or Fondaparinux. Use of graded compression stockings has increased from 59% to 70%. There is increasing evidence that patients undergoing total hip replacement should receive extended prophylaxis for up to 35 days. This could explain why aspirin is commonly used. Most guidelines, however, do not recommend this drug. With the recent launch of two new oral agents we may see a huge change in prophylaxis in Scotland, as 94% of surgeons said they would use extended prophylaxis if a safe oral agent was found

Stable ankle fractures can be successfully treated non-operatively with a below knee plaster cast. In some European centres it is standard practice to administer thromboprophylaxis, in the form of low molecular weight heparin, to these patients in order to reduce the risk of deep venous thrombosis (DVT). The aim of our study was to assess the incidence of DVT in such patients in the absence of any thromboprophylaxis. We designed a prospective study, which was approved by the local ethics committee. We included 100 consecutive patients with ankle fractures treated in a below knee plaster cast. At the time of plaster removal (6 weeks), patients were examined for signs of DVT. A colour doppler duplex ultrasound scan was then performed by one of the two experienced musculoskeletal ultrasound technicians. We found that 5 patients developed a DVT. Two of these were above knee, involving the superficial femoral vein and popliteal vein respectively. The other three were below knee. None of the patients had any clinical symptoms or signs of DVT. None of the patients developed pulmonary embolism. Of these five patients, four had some predisposing factors for DVT. The annual incidence of DVT in the normal population is about 0.1%. This can increase to about 4.5% by the age of 75. DVT following hip and knee replacement can occur in 40-80% of cases. Routine thromboprophylaxis may be justified in these patients. However, with a low incidence of 5% following ankle fractures treated in a cast, we believe that routine thromboprophylaxis is not justified

INTRODUCTION. We examined whether the introduction of an oral factor Xa inhibitor, increased total blood loss in patients undergoing primary total knee arthroplasty surgery. METHODS. Two groups were studied. The intervention group were prescribed a factor Xa inhibitor 6-10 hours post-surgery, and the control group were prescribed low molecular weight heparin (LMWH) 6-10 hours post-surgery. All other factors were kept constant. Pre- and post-operative haemoglobin levels (post-operative on day 2) were recorded. Any requirement for transfusion was also documented. Actual drop in haemoglobin levels was compared between the two groups. RESULTS. 43 patients were prescribed a factor Xa inhibitor and 37 patients LMWH thromboprophylaxis. Baseline pre-operative haemoglobin were comparable (p=0.91; 13.2 vs 13.2g/dL), however, post-operative blood loss was significantly increased in the factor Xa inhibitor group (p=<0.0001; 3.4 vs 2.6g/dL). More patients required transfusion in the factor Xa inhibitor group (0.07% vs 0.03%). Blood loss was significantly increased in the intervention group in patients who were not on anti-platelet medication, when compared with those on concurrent anti-platelet therapy (p=<0.001). CONCLUSIONS. Oral factor Xa inhibitors significantly increase post-operative blood loss in total knee arthroplasty surgery when compared with LMWH. There is a subsequent increased requirement for blood transfusion and the potential complications related to bleeding and transfusion. These factors must be considered and balanced with the ease of oral anticoagulation when introducing these newer agents in total knee arthroplasty patients. The anticoagulatory effects of oral factor Xa inhibitors are most pronounced in patients not on concurrent anti-platelet therapy

Introduction. There are no specific and clear guidelines regarding management of trauma patients who are on Warfarin. The objective of this study was to compare two methods of anticoagulation management in the pre-operative period for this group. Methods. This study was conducted in two phases. In the first half (October 2005 to April 2006) the trauma patients on Warfarin were managed by the traditional method. The second group of patients who were admitted during May to December 2006 was given a single stat dose of Vitamin K (1 mg IV) in addition to stopping Warfarin and starting low molecular weight Heparin. There were 90 patients in this study, 45 in each group. There was no statistically significant difference in age distribution, INR on admission and medical co-morbidities in the two groups. Majority of patients were admitted with fracture neck of femur (43 in each group). All the patients had INR more than 1.5 on admission. Results. INR levels decreased to 1.5 or less in 3.8 days in the first group and 1.6 days in the second group (p< 0.05). The delay in surgery was 6.6 days in group one and was 2.8 days in the patients in group two (p< 0.05). Four patients in the group who did not receive Vitamin K developed medical complications in the pre-operative period. Patients given one dose of Vitamin K did not have any complications pre-operatively. There was no adverse effect of Vitamin K therapy like haemorrhage or clinically evident thrombosis. Conclusion. In our experience 1 mg of intravenous Vitamin K on admission for Warfarin reversal in patients requiring operative management of femur fractures is a safe and effective treatment to avoid delay in treatment

It is widely recognised that pelvic disruption in association with high-energy trauma is a life-threatening injury. The potential morbidity and mortality associated with acetabular injuries are less well understood. Due to chronic underfunding and the absence of a comprehensive and coordinated national approach to the management of acetabular trauma throughout the UK, patients can incur prolonged recumbency. Prompt and appropriate referral for specialist management, thromboprophylaxis and venous thrombosis surveillance are important issues for the referring centre. We performed a postal questionnaire to establish the current clinical practice in the specialist centres throughout the UK in pelvic and acetabular trauma, with respect to time to surgery, thromboprophylaxis, and surveillance. We identified twenty-one units and thirty-seven surgeons in the NHS who deal with pelvic and acetabular injuries. The mean time to surgery from injury in the UK is 8.5 days (range 2-19 days). The larger units that accept and treat patients from outside their region experience the greatest delay to surgery. Mechanical thromboprophylaxis was used in 67% (14) of the units. 24% (5) use arterio-venous boots, 19% (4) use calf pumps, and 52% (11) use TEDS stockings. No unit routinely use prophylactic IVC filters in acetabular trauma. Chemical thromboprophylaxis is routinely used in 100% (21) of the units. 95% (20) used prophylactic doses of unfractionated heparin or low molecular weight heparin. Clinical surveillance alone for thromboembolism is employed in 90% (19) of the units. Only 2 (10%) units routinely perform radiological surveillance with ultrasound Doppler on its acetabular fracture cases pre-operatively. Currently there is no published directory of dedicated pelvic and acetabular surgeons in the UK. There is no general consensus on the approach to thromboprophylaxis and surveillance in acetabular trauma in the UK. There is no consensus approach to thromboprophylaxis and surveillance in the literature

The introduction of direct thrombin inhibitors in arthroplasty surgery has reignited the debate on the risk of wound complications when using chemical thromboprophylaxis. It has been suggested that direct thrombin inhibitors might lead to an increased risk of systemic and operative site bleeding and wound sepsis when compared to low molecular weight heparin. In July 2009, departmental thromboprophylaxis policy for patients undergoing hip and knee replacement surgery (including revision) was changed from subcutaneous enoxaparin for the duration of inpatient stay to dabigatran for 10 days (knees) or 28 days (hips) unless contraindicated. In the 2 years prior to policy change, 1091 patients underwent hip or knee arthroplasty (Group A), with 1150 patients undergoing the same procedures in the 2 years following July 2009 (Group B). A minority of patients were already on warfarin (2% in group 1, 3% in group 2). This study presents a retrospective analysis of all patients who returned to theatre within 30 days of joint replacement surgery to assess whether the change in unit policy caused any discernible increase in bleeding-related complications. In group A, 20 / 1091 patients (1.8%) returned to theatre within 30 days. 9 were for reasons unrelated to thromboprophylaxis (mainly dislocated hips), 4 for gastrointestinal bleeding and 7 for wound complications (haematoma, wound breakdown, or infection). In group B, 22 / 1150 patients (1.9%) returned to theatre within 30 days. 13 were for unrelated reasons, 4 for gastrointestinal bleeding, and 5 for wound complications. One patient with a wound complication was on warfarin and therefore did not receive dabigatran. The lower wound complication rate in group B was not statistically different. This study, in a large heterogeneous group of patients, suggests that a change from enoxaparin to dabigatran does not increase the incidence of early infection, or the risk of bleeding at the operative site or the gastrointestinal tract

The introduction of direct thrombin inhibitors in arthroplasty surgery has reignited the debate on the risk of wound complications when using chemical thromboprophylaxis. It has been suggested that direct thrombin inhibitors might lead to an increased risk of systemic and operative site bleeding and wound sepsis when compared to low molecular weight heparin. In July 2009, departmental thromboprophylaxis policy for patients undergoing hip and knee replacement surgery (including revision) was changed from subcutaneous enoxaparin for the duration of inpatient stay to dabigatran for 10 days (knees) or 28 days (hips) unless contraindicated. In the 2 years prior to policy change, 1091 patients underwent hip or knee arthroplasty (Group A), with1150 patients undergoing the same procedures in the 2 years following July 2009 (Group B). A minority of patients were already on warfarin (2% in group 1, 3% in group 2). This study presents a retrospective analysis of all patients who returned to theatre within 30 days of joint replacement surgery to assess whether the change in unit policy caused any discernible increase in bleeding-related complications. In group A, 20/1091 patients (1.8%) returned to theatre within 30 days. 9 were for reasons unrelated to thromboprophylaxis (mainly dislocated hips), 4 for gastrointestinal bleeding and 7 for wound complications (haematoma, wound breakdown, or infection). In group B, 22/1150 patients (1.9%) returned to theatre within 30 days. 13 were for unrelated reasons, 4 for gastrointestinal bleeding, and 5 for wound complications. One patient with a wound complication was on warfarin and therefore did not receive dabigatran. The lower wound complication rate in group B was not statistically different. This study, in a large heterogeneous group of patients, suggests that a change from enoxaparin to dabigatran does not increase the incidence of local or systemic complications of sufficient severity to warrant return to theatre

Rivaroxaban, an oral, direct FXa inhibitor has shown in large phase III trials to be both superior to enoxaparin a low molecular weight heparin for VTE prophylaxis in patients undergoing MOS, and to also have a good safety profile. RECORD, a pivotal clinical trial program investigating rivaroxaban for the prevention of VTE after THR and TKR surgery, consists of four multinational, randomized, double-blind, double-dummy phase III studies (RECORD1,2,3 and 4) comparing rivaroxaban 10 mg once-daily with enoxaparin 40 mg once-daily or 30 mg twice-daily. The RECORD program has consistently shown superiority of rivaroxaban to enoxaparin at preventing VTE after major orthopaedic surgery. Results from the RECORD 2 study confirmed the benefit of extended thromboprophylaxis after THR. Rivaroxaban was more effective than enoxaparin at reducing the incidence of VTE and all course mortality in patients undergoing THR, with a relative risk reduction (RRR) of 70% in total VTE (RECORD 1). In the TKR populations, rivaroxaban was superior to both once-daily (RECORD 3) and twice-daily (RECORD 4) enoxaparin, with a RRR of 49% and 31.4%, respectively. It also significantly reduced the incidence of symptomatic VTE in TKR patients (RECORD 3). Rivaroxaban groups had low and similar bleeding rates to enoxaparin across the RECORD program. Thus, with its superior efficacy and a good safety profile, oral, once-daily fixed dosing with rivaroxaban could transform the future of VTE prevention after major orthopaedic surgery and improve the quality and reliability of patients care

The introduction of direct thrombin inhibitors in arthroplasty surgery has reignited the debate on the risk of wound complications when using chemical thromboprophylaxis. It has been suggested that direct thrombin inhibitors might lead to an increased risk of systemic and operative site bleeding and wound sepsis when compared to low molecular weight heparin. In July 2009, departmental thromboprophylaxis policy for patients undergoing hip and knee replacement surgery (including revision) was changed from subcutaneous enoxaparin for the duration of inpatient stay to dabigatran for 10 days (knees) or 28 days (hips) unless contraindidated. In the 2 years prior to policy change, 1091 patients underwent hip or knee arthroplasty (Group 1), with1150 patients undergoing the same procedures in the 2 years following July 2009 (Group 2). A minority of patients were already on warfarin (2% in group 1, 3% in group 2). This study presents a retrospective analysis of all patients who returned to theatre within 30 days of joint replacement surgery to assess whether the change in unit policy caused any discernible increase in bleeding-related complications. In group 1, 23/1091 patients (2.1%) returned to theatre within 30 days. 8 were for reasons unrelated to thromboprophylaxis (mainly dislocated hips), 5 for gastrointestinal bleeding (mainly upper GI endoscopy) and 10 for wound complications (haematoma, wound breakdown, or washout of early infection). In group 2, 22 / 1150 patients (1.9%) returned to theatre within 30 days. 12 were for unrelated reasons, 5 for GI bleeding, and 5 for wound complications. The lower return to theatre rate in the second group was not statistically different. This study, in a large heterogeneous group of patients, suggests that a change from enoxaparin to dabigatran does not increase the incidence of early infection, or the risk of bleeding at the operative site or the gastrointestinal tract