The October 2023 Knee Roundup. 360. looks at: Cementless total knee arthroplasty is associated with more revisions within a year; Kinematically and mechanically aligned total knee arthroplasties: long-term follow-up; Aspirin thromboprophylaxis following primary total knee arthroplasty is associated with a lower rate of early periprosthetic joint infection compared with other agents; The impact of a revision arthroplasty network on patient outcomes; Re-revision knee arthroplasty in a tertiary centre: how does infection impact on outcomes?; Does the knee joint have its own microbiome?; Revision knee surgery provision in Scotland; Aspirin is a safe and effective thromboembolic prophylaxis after total knee arthroplasty: a systematic review and meta-analysis; Patellar resurfacing and kneeling ability after total knee arthroplasty: a systematic review

Thromboprophylaxis for venous thromboembolism (VTE) after elective arthroplasty remains controversial. Previous surveys have shown considerable variation amongst orthopaedic surgeons, and the topic is still being debated. Chest physicians recently advocated that randomised data demonstrating a risk reduction with long- established thromboprophylaxis have been ignored by orthopaedic surgeons. We present the current thromboprophylaxis practice amongst AOA members performing elective hip and knee replacements and discuss its rationale. All orthopaedic surgeons in the AOA were asked to complete a one page postal questionnaire asking for information regarding: whether they performed elective hip or knee arthroplasty, which methods of mechanical and/or chemical prophylaxis were routinely used, the time frame in ceasing thromboprophylaxis, the motive in using thromboprophylaxis, and whether thromboprophylaxis guidelines released by the AOA or RACS would be helpful in their orthopaedic practice. Responses from the survery are currently being collected and analysed. These results will be ready for presentation at the AOA conference. The results of the survey will be presented in addition to a discussion of the rationale behind current use of post-operative thromboprophylaxis for elective hip and knee arthroplasty and a need for clinical guidelines

Aims. Thromboprophylaxis following Total Hip Replacement (THR) surgery remains controversial, balancing VTE prevention against wound leakage and subsequent deep infection. We analysed the 90 day cause of death post THR in our institution after the implementation of new thromboprophylactic policy of low dose aspirin for low risk patients, as part of a multimodal regime. Those at high risk were anticoagulated. Patients and methods. The PAS database was used to identify patients undergoing primary THR between January 2012 and June 2017 at The Royal Derby Hospital, and all deaths within 90 days. Trauma cases were excluded. Case note review and Coroner's verdict were utilised to ascertain cause of death. Results were compared to a previous study at the same institution prior to the introduction of the new policy, where thromboprophylaxis was decided upon by surgeon preference for either LMWH, aspirin or warfarin. Results. During this period 4021 THRs were performed. The rate of mortality was 0.22% at 90 days. This compares to 0.58% in the previous study with the only other factor changing being the rapidity of post op mobilization. Of the 9 deaths, only one was due to fatal pulmonary embolism. None of the deaths were at high risk of VTE. This compared to 5 fatal pulmonary embolism deaths in1838 patients in the previous study in the LMWH group. The leading causes of death were heart failure and lower respiratory tract infection. Conclusion. Our institution reports a similar 90 day (0.22%) mortality using aspirin to that in the last 5 years on the NJR (0.3%) in which over 80% use LMWH. We confirm that fatal PE following elective THR with a multi-modal prophylaxis regime is rare. Changing to low dose aspirin in low risk patients is a safe option

Thromboprophylaxis is of particular interest to the NHS due to the number of deaths from preventable hospital-acquired venous thrombo-embolism, considerable treatment cost and related long-term morbidities. In compliance with current NICE guidelines, our departmental protocol for chemical thromboprophylaxis changed from aspirin to clexane. We present a review of the use of both these chemical agents in our hip fracture patients; assessing duration of wound ooze, incidence of symptomatic PE and DVT and thrombocytopaenia. Prospective study of surgically treated hip fractures patients on chemical thromboprophylaxis postoperatively over a 7 month period. Of 224 patients reviewed, 110 fitted our inclusion criteria; 78 on Clexane and 32 on aspirin. Mean patient age: 82.6 years(48–100). Mean hospital stay: 30d ays(6–80). Female predominance (3:1). Mean duration of wound ooze: 6.9 days (1–24) for aspirin and 5.6 days (0–15) for clexane. Symptomatic DVTs: 1(3%) for aspirin and 3(3.8%) for clexane. Symptomatic PE: 0 for aspirin and 1(1.3%) for clexane. Thrombocytopenia: 0 for both groups. Mean duration of wound ooze for both groups was approximately 1 week. Low but significant incidence of thrombo-embolism. Thromboembolism-deterrent-stockings were observed to be unreliable mainly due to skin problems and compliance

We performed a meta-analysis of the English literature to assess the efficacy of four common regimes for thromboembolic prophylaxis after total knee arthroplasty: aspirin, warfarin, low-molecular-weight heparin (LMWH) and pneumatic compression. We reviewed 136 articles and abstracts published between January 1980 and December 1997. Papers not using routine venography and a lung scan or angiography to detect deep-venous thrombosis (DVT) and pulmonary emboli (PE) respectively, were excluded. Of the 136 studies, 23 with 6001 patients were selected. The incidence of DVT was 53% (1701/3214) in the aspirin group, 45% (541/1203) in the warfarin group, 29% (311/1075) in the LMWH group, and 17% (86/509) in the pneumatic compression device group. Intermittent pneumatic compression devices and LMWH were significantly better than warfarin (p < 0.0001) or aspirin (p < 0.0001) in preventing DVT. The incidence of asymptomatic PE was 11.7% in the aspirin group (222/1901), 8.2% (101/1229) in the warfarin group and 6.3% (24/378) in the pneumatic compression group. No studies with LMWH used routine lung scans. Warfarin and pneumatic compression were significantly better than aspirin in preventing asymptomatic PE (p < 0.05). The incidence of symptomatic PE was 1.3% (23/1800) in the aspirin group, 0.4% (2/559) in the warfarin group, 0.5% (2/416) in the LMWH group and 0% (0/177) in the pneumatic compression group. No statistically significant difference was noted between the above prophylatic regimes due to the very small incidence of symptomatic PE. Prophylaxis for thromboembolic disease in TKA may have to include a combination of some of the above regimes to incorporate their advantages

Purpose: Thromboprophylaxis is recommended for at least 10 days and up to 35 days following total hip replacement (THR). Rivaroxaban is an oral, direct Factor Xa inhibitor in advanced clinical development that showed promise in early clinical trials. The purpose of this randomized, double-blind, double-dummy, phase III study was to compare the efficacy and safety of oral rivaroxaban with subcutaneous enoxaparin for 5 weeks, to prevent venous thromboembolism (VTE) in patients undergoing primary THR. Method: Patients received 10 mg rivaroxaban orally 6–8 hours after surgery and once daily thereafter, or 40 mg enoxaparin subcutaneously the evening before surgery (restarting 6–8 hours after surgery), and continued once daily. Thromboprophylaxis was administered for 35±4 days, and mandatory, bilateral venography was conducted the next day. The primary efficacy endpoint was the composite of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE), and all-cause mortality. The primary efficacy analysis was a test for non-inferiority, followed by a test for superiority. Safety endpoints included major and non-major bleeding during the active treatment period. Results: A total of 4541 patients were randomized to receive rivaroxaban or enoxaparin. Rivaroxaban significantly reduced the incidence of the composite of DVT, PE, and all-cause mortality compared with enoxaparin (1.1% vs 3.7%, respectively; p< 0.001; relative risk reduction [RRR] 70%). Rivaroxaban also significantly reduced the incidence of major VTE compared with enoxaparin (0.2% vs 2.0%, respectively; p< 0.001; RRR 88%). There were no significant differences in the incidence of major bleeding (0.3% vs 0.1%; p=0.178) or non-major bleeding (5.8% vs 5.8%; p=1.000) between rivaroxaban and enoxaparin, respectively. There was no evidence of cardiac or liver safety issues. Conclusion: Oral, once-daily rivaroxaban was significantly more effective than subcutaneous, once-daily enoxaparin for extended thromboprophylaxis following THR. Rivaroxaban was not associated with an increased risk of bleeding and had a similar safety profile to enoxaparin. This trial demonstrated the efficacy and safety of a fixed, unmonitored dose of an oral, direct Factor Xa inhibitor – rivaroxaban – for extended thromboprophylaxis after THR

Background: Prophylaxis against thromboembolic complications has become routine after major trauma and major orthopaedic surgery. In contrast, it remains an issue for debate whether prophylaxis after minor surgery and immobilization is necessary, even though these treatments are well-known risk factors for deep vein thrombosis (DVT). Objectives: The objective of this study was to evaluate the efficacy of Dalteparin (5,000 U given subcutaneously once daily for six weeks) during lower limb immobilization after surgical treatment of Achilles tendon rupture. Methods: After surgery, 105 consecutive patients were randomized to a placebo-controlled double-blind study to evaluate the efficacy of given thromboprophylaxis. DVT screening using validated color duplex sonography was performed three weeks and six weeks after surgery, and all DVTs were confirmed with phlebography. Results: Primary endpoint analysis was available for 91 patients. DVT was diagnosed in 16/47 patients (34%) in the Dalteparin group and in 16/44 patients (36%) in the placebo group. These figures are not significantly different (p=0.8). Proximal DVT was diagnosed in one patient (2%) in the Dalteparin group and in three patients (6%) in the placebo group (p=0.6). No pulmonary emboli or major bleeding occurred in either of the groups. Conclusions: DVT is common after surgical treatment of Achilles tendon rupture and therefore effective thromboprophylaxis is desirable. Thromboprophylaxis with Dalteparin however, does not affect the incidence of DVT during the immobilization after Achilles tendon rupture surgery. Long-term effects of immobilization, such as the risk for post-thrombotic syndrome, need to be investigated further

Introduction: After total hip replacement (THR), thromboprophylaxis for at least 10 days and for up to 35 days is recommended – yet a convenient, oral anticoagulant is not currently available. Rivaroxaban – a once-daily, oral, direct Factor Xa inhibitor with a predictable clinical profile – is in advanced clinical development. RECORD1, a multinational, randomized, double-blind, double-dummy, phase III study, compared once-daily oral rivaroxaban with subcutaneous enoxaparin for 5 weeks following THR. Methods: In total, 4541 patients were randomized to receive oral rivaroxaban 10 mg (6–8 hours after surgery and once daily thereafter), or 40 mg enoxaparin (administered subcutaneously the evening before surgery, resumed 6–8 hours after surgery, and continued once daily). Thromboprophylaxis was administered for 35±4 days; mandatory, bilateral venography was conducted the next day. The primary efficacy endpoint was the composite of any deep vein thrombosis (DVT), nonfatal pulmonary embolism (PE), and all-cause mortality. Safety endpoints included major and non-major bleeding during the active treatment period. Results: The incidence of the composite of DVT, PE, and all-cause mortality was significantly lower for rivaroxaban compared with enoxaparin (1.1% vs 3.7%, respectively; p< 0.001; relative risk reduction [RRR] 70%). The incidence of major VTE was also significantly lower for rivaroxaban compared with enoxaparin (0.2% vs 2.0%, respectively; p< 0.001; RRR 88%). There were no significant differences in the incidence of major bleeding (0.3% vs 0.1%; p=0.178) or non-major bleeding (5.8% vs 5.8%; p=1.000) between rivaroxaban and enoxaparin, respectively. There was no evidence of cardiac or liver safety issues. Conclusions: Following THR, thromboprophylaxis with once-daily, oral rivaroxaban was shown to be significantly more effective than subcutaneous, once-daily enoxaparin – without an increased risk of bleeding. This trial demonstrates the efficacy and safety of oral rivaroxaban using a fixed, unmonitored, once-daily dose for extended thromboprophylaxis after THR

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

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.

Rivaroxaban is a novel, oral, once-daily, direct Factor Xa inhibitor in advanced clinical development. RECORD1 was a multinational, randomized, double-blind, double-dummy, phase III study investigating the efficacy and safety of extended thromboprophylaxis with rivaroxaban compared with subcutaneous enoxaparin following THR. Patients (N=4541) were randomized to receive oral rivaroxaban 10 mg (6–8 hours after surgery and once daily thereafter) or subcutaneous enoxaparin 40 mg (administered the evening before surgery, 6–8 hours after surgery, and once daily thereafter) for 35±4 days. The primary efficacy outcome was the composite of deep vein thrombosis (DVT: symptomatic or detected by mandatory, bilateral venography if asymptomatic), non-fatal pulmonary embolism (PE), and all-cause mortality up to day 36±6. Major venous thromboembolism (VTE), the composite of any DVT, non-fatal PE and VTE-related death, was a secondary outcome. Safety endpoints included major and non-major bleeding while receiving study medication. Rivaroxaban significantly reduced the incidence of the primary efficacy outcome compared with enoxaparin (1.1% vs 3.7%, respectively; p< 0.001; relative risk reduction [RRR] 70%). Rivaroxaban also significantly reduced the incidence of major VTE compared with enoxaparin (0.2% vs 2.0%, respectively; p< 0.001; RRR 88%). There were no significant differences in the incidence of major bleeding (0.3% vs 0.1%; p=0.178) or non-major bleeding (5.8% vs 5.8%; p=1.000) between rivaroxaban and enoxaparin, respectively. There was no evidence of liver safety issues associated with rivaroxaban. Thromboprophylaxis with once-daily, oral rivaroxaban was significantly more effective than subcutaneous enoxaparin following THR without an increased risk of bleeding. This trial demonstrates the efficacy and safety of a fixed, unmonitored, once-daily dose of oral rivaroxaban for extended thromboprophylaxis after THR

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.

We report preliminary results from the first, multicenter prospective study designed to define the incidence of symptomatic (Venous Thromboembolism) VTE in patients with isolated leg fractures distal to the knee. Eight hundred and twenty-six enrolled patients have completed three months of follow up. By three months, only seven patients had sustained a symptomatic VTE with no fatal PE. Symptomatic and fatal VTE were infrequent complications after isolated leg fractures distal to the knee without thromboprophylaxis. Routine thromboprophylaxis may not be warranted in isolated leg fractures distal to the knee. To report results from the first, multicenter prospective study designed to define the incidence of symptomatic Venous Thromboembolism (VTE) in patients with isolated leg fractures distal to the knee. Symptomatic and fatal VTE are infrequent complications after isolated leg fractures distal to the knee without thromboprophylaxis. Routine thromboprophylaxis may not be warranted in isolated leg fractures distal to the knee. From August 2002 to April 2004, one thousand eight hundred and eight consecutive patients with isolated leg fractures distal to the knee were screened for entry at five hospitals in Ontario. Patients with major trauma, active cancer and previous VTE were excluded. Thromboprophylaxis was not allowed. Patients were followed prospectively for three months, with telephone calls at fourteen days, six weeks and three months. Suspected DVT and PE were investigated in a standardized manner. Eight hundred and twenty-six enrolled patients have completed three months of follow up. The mean age was forty-five years (range sixteen to ninety-three) and 59.5% of this cohort was female. 99% of these fractures were unilateral and 97% were closed. Fractures included: fibula (38%), metatarsal (29%), phalanges (13%), calcaneus, talus or tarsal (10%), tibia (10%) and patella (7%). Only 11% of fractures were surgically treated. 88% of fractures received a cast or splint for a mean duration of 41+/− 20 days. Complete follow-up was available for 97.5% of this cohort. By three months only seven patients had sustained a symptomatic VTE (2 proximal DVT, 3 calf DVT, 2 PE) with no fatal PE-an incidence of 0.9% (95% CI 0.3 to 1.8%). Funding: This study was funded by a research grant from Pharmacia

Venous thromboembolism (VTE) is the second most common complication and pulmonary embolism (PE) is the fourth most common cause of death after a hip fracture. Despite thromboprophylaxis, deep vein thrombosis (DVT) is detected in up to 45% of hip fracture patients. Thrombelastography (TEG) is a whole-blood, point of care test capable of providing clinicians with a global assessment of the clotting process, from fibrin formation to clot lysis. Maximal amplitude (mA) from TEG analysis is a measure of clot strength. Elevated admission mA values of >65mm and >72mm have been determined to be independent predictors of in-hospital PE. The coagulation index (CI) is calculated based on TEG parameters and defines hypercoagulable state as CI >3. This study aimed to use serial TEG analysis to determine the duration of hypercoagulable state after hip fracture.

A prospective cohort of hip fracture patients >50 years of age amenable to surgical treatment (AO 31A1–A3 & 31B1–B3) were enrolled at a Level I trauma centre. Serial TEG analysis (TEG 6S) was performed every 24-hours from admission until 5-days post-operatively and at 2- and 6-week follow-up visits. All patients received a minimum of 28 days of thromboprophylaxis. Descriptive statistics and single sample t-tests were used for comparison of mA to the 65mm threshold.

Thirty-five patients (26 female) with a median age of 83 (range = 71–86) years were included. On admission, 31.4% and 82.9% of patients were hypercoagulable based on mA >65mm and CI, respectively. At 2 weeks, all patients remained hypercoagulable, however, mA >72mm showed that 16 patients (47.1%) were at even higher risk for VTE. At 6-weeks, 65.7% and 97.1% of patients were hypercoagulable based on mA >65mm and CI, respectively. When compared with the mA >65mm threshold, patients were hypocoagulable at the time of admission (mA = 62.2 (±6.3), p = 0.011), but became significantly more hypercoagulable at 2-weeks (mA = 71.6 (±2.6), p < 0 .001), followed by continued hypercoagulability at 6-weeks, however not significantly elevated above the 65mm threshold (mA = 66.2 (±3.8), p = 0.058). One patient developed a symptomatic DVT at 2-weeks and had a mA = 72.9 and a CI of 5.9.

This is the first study to demonstrate that >50% of hip fracture patients remain hypercoagulable 6 weeks post fracture despite thromboprophylaxis, and there are individual hypercoagulable responses. This is critical, as guidelines only recommend 28 to 35 days of thromboprophylaxis in this high-risk population. Previously determined mA thresholds may be a more sensitive test for risk-stratifying patients' VTE risk than the CI threshold. Additionally, assessing ΔmA using serial TEG may better predict VTE risk.

Purpose: We conducted the first, multicentre, prospective cohort study to define the incidence of symptomatic venous thromboembolism (VTE) in patients with tibia and ankle fractures treated conservatively and relatively minor lower leg fractures. The reported incidence of deep vein thrombosis (DVT) using routine venography in patients with lower leg injury requiring cast immobilization is approximately 20–40%, which has lead to the routine use of anticoagulant prophylaxis for several weeks in many such patients. However the vast majority of venographically-detected DVTs are asymptomatic, distal thrombi whose clinical relevance is uncertain. Therefore venography is not the best outcome measure to assess the burden of clinically important VTE. Method: Consecutive patients with tibia and fibula fractures (treated non-operatively) and patella and foot fractures, (treated operatively or conservatively) were assessed for eligibility at 5 Ontario hospitals. Patients were enrolled after informed consent within 96 hours of injury and were followed prospectively, by telephone, at 2, 6 and 12 weeks. Those with major trauma, active cancer, and previous VTE were excluded. Thromboprophylaxis was not allowed. Education regarding symptoms of VTE was provided at study entry and patients were asked about VTE symptoms at follow up. Suspected VTE was investigated in a standardized manner. Results: From August 2002 to June 2005, 1200 patients were enrolled from 2446 consecutively screened patients. 98% of patients completed 3-month follow-up. The mean age was 45 years (16 to 93) and 60% were female. The most common fractures were fibular (39%) and most injuries were caused by falls (75%). 99 % of these fractures were unilateral. Most fractures did not require surgical repair (93%), and 82% of patients were immobilized by cast or splint for an average of 42 ±32 days. Overall, 7 patients had symptomatic, objectively confirmed VTE (2 proximal DVT, 3 calf DVT, 2 PE) with no fatal PE – an incidence of 0.6 % (95% CI 0.2 to 1.2). Conclusion: Symptomatic VTE is an infrequent complication after these fractures without thromboprophylaxis. Therefore routine thromboprophylaxis is neither warranted, nor likely to be cost-effective in these patients. This study also highlights the significant discrepancy between clinical endpoint studies and studies using venography

Aims

The aims of this study were to compare the efficacy of two agents, aspirin and warfarin, for the prevention of venous thromboembolism (VTE) after simultaneous bilateral total knee arthroplasty (SBTKA), and to elucidate the risk of VTE conferred by this procedure compared with unilateral TKA (UTKA).

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.