Does total hip arthroplasty predispose to chronic venous insufficiency?

Comparison of Postoperative Bleeding in Total Hip and Knee Arthroplasty Patients Receiving Rivaroxaban or Enoxaparin

Background: The Regulation of Coagulation in Orthopedic Surgery to Prevent Deep Venous Thrombosis and Pulmonary Embolism (RECORD) 1 to 4 trials compared rivaroxaban 10 mg daily with commonly used doses of enoxaparin and demonstrated similar rates of VTE and bleeding. Objective: To evaluate bleeding events between patients who received enoxaparin or rivaroxaban for prevention of venous thromboembolism (VTE) following total hip arthroplasty (THA) or total knee arthroplasty (TKA). Methods: Retrospective cohort that compared patients undergoing THA and TKA who received enoxaparin (enoxaparin) with those who received rivaroxaban (rivaroxaban) and also with those who received enoxaparin in the RECORD 1 to 4 trials (enoxaparin RECORD). The primary outcome was any postoperative bleeding, defined as a composite of major and clinically relevant nonmajor bleeding based on the definitions in the RECORD 1 to 4 trials. Results: There was a lower rate of any postoperative bleeding (2.2% vs 6.8%, P = 0.004) in patients who received enoxaparin compared with rivaroxaban, and bleeding rates between the enoxaparin group and the enoxaparin RECORD groups were similar (2.2% vs 2.5%, P = 0.085). Major bleeding in the enoxaparin group (0.2%) was not significantly different from that in the rivaroxaban group (1.4%, P = 0.12) or the RECORD group (0.2%, P = 0.93). Clinically relevant nonmajor bleeding was also lower in the enoxaparin group compared with the rivaroxaban group (2.0% vs 5.5%, P = 0.012). Conclusions: The use of enoxaparin for VTE prophylaxis following THA and TKA was associated with a lower rate of the primary outcome (any postoperative bleeding) compared with the use of rivaroxaban in a similar cohort of patients.

Are we missing post-thrombotic syndrome syndrome? An orthopaedic perspective in lower limb arthroplasty

2-5% of patients undergoing hip or knee arthroplasty develop a symptomatic DVT; there is evidence to suggest that without prophylaxis 40-60% of patients have a subclinical DVT. This can be reduced by around half with appropriate thromboprophylaxis; there still remains a significant incidence of subclinical DVT. Therefore, it is important to know, as orthopaedic surgeons, if our patients undergoing large joint arthroplasty are being adversely affected. Post-thrombotic syndrome (PTS) is usually associated with symptomatic DVT, and the purpose of this paper is to address if asymptomatic DVT is also associated with an increased risk of PTS. The majority of evidence gathered does not support a link; therefore, there is no evidence to warrant a change in practice to warn patients of a potential risk or to routinely screen asymptomatic patients.

Meta-analysis of low molecular weight heparin versus placebo in patients undergoing total hip replacement and post-operative morbidity and mortality since their introduction

OBJECTIVES

1) To establish the clinical validity for in-patient low molecular weight heparin (LMWH) following total hip replacement (THR) through a meta-analysis of peer reviewed and published randomised placebo controlled trials (RCTs). 2) To establish whether modern peri-operative practices were associated with changes in rates of clinical venous thromboembolic (VTE) and all-cause mortality after THR by review of series of patients receiving in-patient LMWH published between 1985 and 2000. DATASOURCES: Medline and Embase (from 1980 to 2005), Datastar and Proquest databases were searched and references from bibliographies traced.

REVIEW METHODS

Studies of adult patients receiving in-patient LMWH following elective primary or revision THR were sought and data abstracted. The first part of our analysis included only randomised placebo controlled trials. For the second part, randomised control trials were included and divided by their year of completion into three groups.

RESULTS

We found no difference between LMWH and placebo in the risk of fatal pulmonary embolism (PE), other deaths, all cause mortality or major bleeding. LMWH reduced non-fatal PE (OR=0.14, 95%CI 0.03 to 0.74, p=0.029) at the expense of haematoma formation (7/147 vs 0/149, p=0.015). 35 studies were included in the second part of our analysis. Point estimates of rates of fatal and non-fatal pulmonary embolism and other deaths suggest a decline over time but fell short of statistical significance.

CONCLUSION

Clinically relevant VTEs are a rare complication following THR. The lower risk of VTE narrows the risk benefit of potent pharmacological thromboprophylaxis. We do not support their use in patients undergoing THR without additional thromboembolic risk factors.

Post-thrombotic syndrome after total hip arthroplasty is uncommon

BACKGROUND

Deep vein thrombosis (DVT), usually asymptomatic, is common after total hip arthroplasty (THA). Post-thrombotic syndrome (PTS) is a potential late complication of DVT, but there is limited data on its occurrence.

PATIENTS AND METHODS

This was a prospective cohort study of subjects at one hospital who had participated in a trial of thromboprophylaxis for THA and who had postoperative venography. Data were collected at baseline and 2-4 years later to ascertain symptoms of PTS using a modification of a validated scoring system. Outcomes were collected without knowledge of baseline characteristics or venogram results. Potential predictors of PTS were explored using exact logistic regression analyses.

RESULTS

The cohort (n=188) had a mean age of 63 years, 51% were male, 35% had a BMI of>30, and 4% had a prior history of DVT. 25 patients (13%) had DVTs on venography. 12 patients (6%, 95% CI: 3-11) subsequently developed symptoms consistent with PTS, 7 with bilateral symptoms. Most affected limbs (15 of 19) had no postoperative DVT. No statistically significant predictors of PTS were found.

INTERPRETATION

Symptoms of PTS are infrequent after THA in patients who receive some form of thromboprophylaxis. Our findings, which are consistent with the existing literature, suggest that there is a potential benefit to giving thromboprophylaxis for reduction of symptomatic PTS.

Mechanical and pharmacological methods to prevent venous thromboembolism

Today, it is possible to define certain risk groups for the development of venous thromboembolism, most studies having been conducted on post-operative venous thromboembolism. Nonetheless, the risk classification is rather inexact, resulting in many patients receiving prophylaxis who would not have gone on to develop the complication. However, the current prophylactic methods are safe and can therefore also be used in the post-operative situation. The dominating pharmacological substances are unfractionated heparin, low-molecular-weight heparins and the pentasaccharide fondaparinux. In some situations (such as elective hip surgery and likely hip fracture surgery, and in many cases where malignant diseases in the abdomen/pelvis have been operated upon), extended prophylaxis for 1 month should be considered.

The post-thrombotic syndrome: current knowledge, controversies, and directions for future research

The post-thrombotic syndrome (PTS) is a long-term complication of deep venous thrombosis (DVT) that is characterized by chronic, persistent pain, swelling and other signs in the affected limb. PTS is common, burdensome and costly. It is likely to increase in prevalence, since despite widespread use of and improvements in the efficacy of thromboprophylaxis, the incidence of DVT has not decreased over time. About 20-50% of patients develop PTS within 1-2 years of symptomatic DVT, and severe PTS, which can include venous ulcers, occurs in 5-10% of cases. Although there is no gold standard for the diagnosis of PTS, the presence of typical clinical features in a patient with previous DVT provides strong supporting evidence. Objective evidence of venous valvular incompetence helps to confirm the diagnosis in symptomatic patients. Preventing ipsilateral recurrence of DVT, by ensuring an adequate duration and intensity of anticoagulation for the initial DVT and by prescribing situational thromboprophylaxis after discontinuation of oral anticoagulants, is likely to reduce the risk of developing PTS. There is no proven role for thrombolysis of the initial DVT to prevent PTS. Daily use of graduated compression stockings after DVT may reduce the risk of PTS, and may prevent worsening of established PTS. Pending the results of ongoing studies, stockings are recommended in patients with persistent symptoms or swelling after DVT. Future research should focus on standardizing criteria for PTS diagnosis, identification of DVT patients at high risk for PTS, and rigorously evaluating the effectiveness of stockings, thrombolysis, and venoactive drugs in preventing or treating PTS.

Low-molecular-weight heparin: the optimal duration of prophylaxis against postoperative venous thromboembolism after total hip or knee replacement

Venous thromboembolism is a major health problem. In about 20% of cases, the initial clinical manifestation of venous thromboembolism is sudden death due to pulmonary embolism. Consequently, appropriate prophylaxis is critical in order to improve survival. Because patients with recent surgery have a 22-fold increased risk of postoperative venous thromboembolism, a large research effort has been directed toward identifying the safest and most effective prophylaxis after surgery, especially after total hip or knee replacement. While low-molecular-weight heparin is the most effective prophylaxis currently available, from 15% to 30% of hip or knee replacement patients still develop deep vein thrombosis by the time of hospital discharge, and another 25% develop new deep vein thrombosis by 3 weeks after discharge. Extended out-of-hospital low-molecular-weight heparin prophylaxis can safely reduce the prevalence of deep vein thrombosis by about 50%. However, essentially all of these thrombi are small, asymptomatic, and resolve without serious clinical sequelae. Based on one clinical trial, out-of-hospital low-molecular-weight heparin prophylaxis could reduce the incidence of symptomatic venous thromboembolism or all-cause death after discharge by a maximum of 2.2%. At current drug costs, universal out-of-hospital low-molecular-weight heparin prophylaxis is unlikely to be cost-effective. For most patients, 7 to 10 days of low-molecular-weight heparin prophylaxis is adequate. Future research should be directed at identifying patients at risk for out-of-hospital venous thromboembolism, and targeting extended prophylaxis to those at highest risk.

Femoral medullary infarction secondary to canine total hip arthroplasty

OBJECTIVE

To evaluate the prevalence of femoral intramedullary infarction after total hip arthroplasty (THA) and to determine whether any specific femoral morphology predisposes to bone infarction.

STUDY DESIGN

Retrospective clinical study.

SAMPLE POPULATION

All dogs from our hospital population undergoing THA between 1984 and 1997 with radiographic follow-up available at 1 year or more postoperatively.

METHODS

A case control study was conducted within the THA group to determine risk factors predisposing to femoral infarction after THA. Medical records and radiographs were reviewed. Data were collected on clinical parameters, femoral morphology, prosthesis, and bone changes. Radiographic diagnosis was confirmed using histopathology in 11 femora. Radiographs of 50 age-matched control dogs weighing more than 20 kg with coxofemoral degenerative joint disease were randomly chosen to determine the prevalence of bone infarction in nonoperated dogs.

RESULTS

Ninety-one dogs with 110 THA were included in the study. Fifteen of the 110 femora with THA had radiographic evidence of infarction (14%). Infarction was not present in any femora in the control group. There was no significant difference in the prevalence of infarction between dogs that received cemented or uncemented prostheses. Clinical signs were not reported in any patient that developed femoral infarction. Young age (P = .03) and a distance between the greater trochanter and nutrient foramen greater than 79 mm (P = .008) predisposed dogs to femoral infarction. Over time, three infarcts decreased in size radiographically, five remained unchanged, and three expanded. An osteosarcoma developed at the site of a bone infarct in one dog.

CONCLUSION

Femoral intramedullary infarction occurred in 15 of 110 THA. Young age at the time of THA and a greater distance between the greater trochanter and the nutrient foramen predisposed to infarction.

CLINICAL RELEVANCE

Intramedullary infarction occurs after canine THA. These bone infarcts do not appear to cause clinical signs; however, they may present a diagnostic challenge. Malignant transformation could potentially result from medullary infarction.

Comparison of the use of a foot pump with the use of low-molecular-weight heparin for the prevention of deep-vein thrombosis after total hip replacement. A prospective, randomized trial

We conducted a prospective, randomized trial to compare the safety and effectiveness of the A-V Impulse System foot pump with that of low-molecular-weight heparin for reducing the prevalence of deep-vein thrombosis after total hip replacement. Of 290 patients who were to have a primary total hip replacement, 143 were randomized to receive enoxaparin (forty milligrams daily) for seven days after the operation and 147, to use the foot pump for seven days. The primary outcome measure was the prevalence of deep-vein thrombosis, as determined by venography on the sixth, seventh, or eighth postoperative day. Secondary outcome measures included transfusion requirements, intraoperative blood loss, postoperative drainage, blood-loss index, appearance of the site of the wound according to a subjective visual-analog scale, and swelling of the thigh. The patients' compliance with the regimen for use of the foot pump was monitored with an internal timing device, and their acceptance of the device was assessed with a questionnaire. Symptoms consistent with pulmonary embolism were investigated with ventilation-perfusion scanning. The patients were contacted later for detection of symptoms of venous thromboembolism that may have occurred during the first three months after discharge from the hospital. Venography was performed on 274 patients: 136 who used the foot pump and 138 who received enoxaparin. Deep-vein thrombosis was detected in twenty-four (18 per cent) of the patients who used the foot pump compared with eighteen patients (13 per cent) who received enoxaparin (95 per cent confidence interval for the difference in proportions, -3.9 to +13.0 per cent). Thrombosis in the calf was found in seven patients (5 per cent) in the former group compared with six patients (4 per cent) in the latter (95 per cent confidence interval for the difference, -4.2 to +5.8 per cent), and proximal thrombosis was observed in seventeen patients (13 per cent) in the former group compared with twelve patients (9 per cent) in the latter (95 per cent confidence interval for the difference, -3.5 to +11.1 per cent). None of these differences was significant. No patient in either group had major proximal deep-vein thrombosis; all proximal thrombi were isolated entities involving the femoral valve cusp and were of unknown importance. One patient who used the foot pump had a non-fatal pulmonary embolism. One patient who received enoxaparin had a symptomatic deep-vein thrombosis during hospitalization. Two patients (one from each group [0.7 per cent]) were readmitted to the hospital because of a symptomatic deep-vein thrombosis despite normal venographic findings at the time of discharge. There was no difference in the transfusion requirements or the intraoperative blood loss between the two groups. There were more soft-tissue side effects in the patients who received enoxaparin than in those who used the foot pump: there was more bruising of the thigh and oozing of the wound (p < 0.001 for each), postoperative drainage (578 compared with 492 milliliters; p = 0.014), and swelling of the thigh (twenty compared with ten millimeters; p = 0.03). Of 124 patients who used the foot pump and were asked about the acceptability of the device, fourteen (11 per cent) said that it was uncomfortable, twenty-one (17 per cent) reported sleep disturbance, and four (3 per cent) stated that they had stopped using the device. Conversely, ten (8 per cent) found it relaxing. We concluded that the foot pump is a suitable alternative to low-molecular-weight heparin for prophylaxis against thromboembolism after total hip replacement and that it produces fewer soft-tissue side effects. Tolerance of the device is a problem for some patients.