Duplex ultrasonography after total hip or knee arthroplasty

Mechanical thromboprophylaxis would suffice after total knee arthroplasties in Asian patients?

PURPOSE

Our prospective study evaluated the incidence and location of deep vein thrombosis (DVT), the risk factors for PE and the natural history of DVT after TKA in patients who have received only mechanical compression device without having any chemical thromboprophylaxis or therapeutic treatment.

METHODS

We studied 408 consecutive patients (691 knees) who underwent primary TKA; 283 patients had one-stage bilateral TKAs and 125 had unilateral TKAs. Coagulation assays, the full blood count and blood typing tests, and serum chemical profiles were undertaken in all patients on three separate occasions. Molecular genetic testing was performed preoperatively to detect the genetic traits involving DVT. Bilateral simultaneous or unilateral venograms were carried out at 6 or 7 days after operation. Perfusion lung scanning was undertaken before and at 7 or 8 days after operation.

RESULTS

In the 691 venograms in 408 patients, only 4 knees (0.6%) were positive for fresh thrombi. In the 4 knees with DVT, thrombi were located in the calf veins. We observed factor V Leiden mutation, antithrombin-III level, and prothrombin promoter G20210A mutation were absent in all patients. We saw no relationship between DVT and coagulation or thrombophilic data. No pulmonary embolism (PE) occurred as shown by negative perfusion lung scan and absence of symptoms.

CONCLUSION

We concluded that the combinations of absent thrombophilic polymorphisms with low clinical prothrombotic risk factors led to low prevalence of DVT and virtually absent PE after TKA in the current series of patients, who had received mechanical compression device only without chemical thromboprophylaxis.

Flowtron foot-pumps for prevention of venous thromboembolism in total hip and knee replacement

INTRODUCTION

Mechanical prophylaxis with foot-pumps provides an interesting alternative to chemical agents in the prevention of venous thomboembolism following major orthopaedic surgery procedures. The aim of this prospective study was to assess efficacy and safety of the Flowtron(®) foot-pumps system following total hip and knee replacement. The foot pumps were used as main tool for prevention of thromboembolic events, in most cases in association with a variety of chemicals.

METHODS

The primary endpoint of the study was to assess the incidence of deep vein thrombosis and pulmonary embolism after total hip and knee replacement. The secondary endpoints included postoperative bleeding, swelling, bruising and wound ooze.

RESULTS

424 consecutive patients were included in the study. Symptomatic deep vein thrombosis was detected in 7 patients (1.6%). All symptomatic deep vein thromboses were detected after discharge before the six week follow-up clinic. Five non-fatal pulmonary embolisms occurred (1.2%). Only one patient presented a major wound bleeding (0.2%). The mean difference of swelling of thigh pre-versus postoperatively was only 22.8 mm.

DISCUSSION

In conclusion, thromboembolism prophylaxis after total hip and knee replacement using Flowtron(®) foot-pumps as main prevention tool of an individualised protocol appears effective and safe. This is the first clinical report related to this popular brand of foot pumps.

The incidence of pulmonary embolism and deep vein thrombosis after knee arthroplasty in Asians remains low: a meta-analysis

BACKGROUND

While Western literature has mostly reported the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) after TKA with chemoprophylaxis, the Asian literature still has mostly reported the incidence without chemoprophylaxis. This may reflect a low incidence of DVT and PE in Asian patients, although some recent studies suggest the incidence after TKA in Asian patients is increasing. Moreover, it is unclear whether the incidence of DVT and PE after TKA is similarly low among different Asian countries.

QUESTIONS/PURPOSES

We therefore determined the overall incidence of symptomatic PE and DVT without chemoprophylaxis after TKA in the Asian population, determined whether the incidence had a tendency to increase over time in Asia, and compared the incidence of symptomatic PE and DVT among Asian countries through a meta-analysis.

METHODS

We searched the PubMed, Embase, Cochrane Library, Web of Science, and Google Scholar websites for prospective studies published between 1996 and 2011. A total of 1947 patients from 18 studies were reviewed for meta-analysis.

RESULTS

The incidence of symptomatic PE was 0.01%. The incidences of overall DVT, proximal DVT, and symptomatic DVT were 40.4%, 5.8% and 1.9%, respectively. We found no difference in incidence of symptomatic PE among Asian countries and no trends in changes of the incidence over time.

CONCLUSIONS

The incidence of symptomatic PE and DVT after TKA without prophylaxis is low in Asian countries and has not changed over time, despite Westernizing lifestyles and an aging populace. Further investigation with large randomized studies is necessary to confirm our findings and identify risk factors predisposing to DVT.

Systematic review and meta-analysis on the rate of postoperative venous thromboembolism in orthopaedic surgery in Asian patients without thromboprophylaxis

BACKGROUND

Postoperative venous thromboembolism (VTE) is a common life-threatening complication after surgery. This review analysed the rate and mortality of VTE after orthopaedic surgery in Asia.

METHODS

Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography or ultrasonography; hip fracture surgery (HFS), total hip arthroplasty (THA) or total knee arthroplasty (TKA); and no thromboprophylaxis. The pooled proportion was back-calculated by Freeman-Tukey variant transformation, using a random-effects model.

RESULTS

Twenty-two studies (total population 2454) published from 1979 to 2009 were included. Using venography, the pooled rates of all-site, proximal, distal and isolated distal DVT were 31·7, 8·9, 22·5 and 18·8 per cent respectively. With duplex ultrasonography, the respective rates were 9·4, 5·9, 5·9 and 5·8 per cent. After THA or HFS, using venography, the pooled rates of all-site and proximal DVT were 25·8 and 9·6 per cent; with ultrasonography, the respective rates were 10·8 and 7·2 per cent. In TKA groups, using venography, the pooled rates of all-site and proximal DVT were 42·5 and 8·7 per cent; with ultrasonography, the respective rates were 9·5 and 5·2 per cent. The overall pooled rates of symptomatic DVT and symptomatic pulmonary embolism (PE) were 4·5 and 0·6 per cent. No patient died from PE (pooled rate 0·2 per cent).

CONCLUSION

None of these Asian patients undergoing orthopaedic surgery died from VTE. Pooled rates of proximal and symptomatic DVT were lower than in Western reports.

Deep vein thrombosis after total hip arthroplasty in Korean patients and D-dimer as a screening tool

INTRODUCTION

This prospective study was designed to confirm risk factors and to assess the incidence of deep vein thrombosis after total hip and surface replacement arthroplasty in Korean patients not receiving anticoagulation prophylaxis and to determine efficacy of plasma D-dimer levels as a screening test.

MATERIALS AND METHODS

From May 2003 to August 2004, 221 consecutive patients undergoing unilateral total hip arthroplasty and hip resurfacing were evaluated. All patients underwent ultrasonography preoperatively and venography and/or ultrasonography on postoperative day 7. Plasma D-dimer levels were estimated by latex immuno-assay preoperatively and on days 3 and 7 postoperatively.

RESULTS

Of the 221 patients in our cohort, 23 developed deep vein thrombosis (10.4%). Age (r = 0.245, P < 0.001) and gender (r = 0.155, P = 0.021) significantly correlated with deep vein thrombosis. Rise in incidence paralleled increase in age (X(2) = 32.860, P < 0.001). D-dimer levels on postoperative days 3 (gamma = 0.364, P < 0.001) and 7 (gamma = 0.470, P < 0.001) were significantly correlated to the development of DVT.

CONCLUSION

While incidence of deep vein thrombosis in Korean population after THA was lower than that in the West; it increased with age, and in female gender. Significant correlation was found between D-dimer levels and the development of deep vein thrombosis.

Foot pumps without graduated compression stockings for prevention of deep-vein thrombosis in total joint replacement: efficacy, safety and patient compliance

Mechanical prophylaxis with foot pumps provides an interesting alternative to chemical agents in the prevention of thromboembolic disease following major orthopaedic surgical procedures. Recent studies have suggested that the simultaneous use of graduated compression stockings (GCS) may hinder the pneumatic compression effect of foot pumps. The hypothesis of this prospective study was that the use of foot pumps without GCS does not affect the efficacy of deep-vein thrombosis (DVT) prophylaxis and improves patient compliance. A total of 846 consecutive patients admitted at a single institution undergoing total hip (THR) or knee replacement (TKR) were included in the study. The A-V Impulse System foot-pump unit (Orthofix Vascular Novamedix, Andover, UK) was used in all patients. Of these 846 patients, 46 discontinued the use of foot pumps, leaving 400 patients who received foot pumps in combination with GCS and 400 patients with foot pumps alone. Eleven patients of the stocking group (2.7%) and nine patients of the no-stocking group (2.3%) developed postoperative symptomatic DVT (p=0.07). DVT was more frequent in TKR (10/364; 2.7%) than in THR (10/436; 2.3%). Non-fatal pulmonary embolism occurred in four of the 20 patients with symptomatic DVT, two patients each of the stocking and no-stocking groups. The foot-pump discontinuation rate of patients treated with stockings was 7% versus 4% of the patients treated without stockings (p<0.05). In conclusion, management of patients with foot pumps without GCS does not reduce the efficacy of DVT prophylaxis after THR and TKR and improves patient compliance.

Routine duplex ultrasound screening after TKA is not necessary

We determined if negative ultrasound screening at the time of acute care hospital discharge or 2 weeks post operatively would reliably identify patients without deep venous thrombosis, thus allowing discontinuation of warfarin chemoprophylaxis. Patients undergoing primary TKA (1344) were treated with adjusted-dose warfarin (target prothrombin time, 15-18 seconds; internationalized normalization ratio, 1.4-1.7) until screening and then aspirin (325 mg po bid) until 6 weeks postoperatively. Deep venous thrombosis as determined by ultrasound was the measured outcome. From 1994 to 1997, 525 patients underwent screening ultrasound before discharge (usually postoperative Day 3): 12 (2.3%) patients with proximal deep venous thrombosis and three (0.6%) patients with distal deep venous thrombosis were identified. From 1997 to 2001, 819 patients underwent ultrasound screening at Day 14 postoperatively: 10 (1.2%) patients with proximal deep venous thrombosis and 29 (3.6%) patients with distal deep venous thromboses were identified. There was no difference in proximal deep venous thrombosis detection, but there was a difference in distal deep venous thrombosis detection. We no longer screen asymptomatic patients with ultrasound for deep venous thrombosis after TKA.

Deep vein thrombosis after total hip and knee arthroplasty in Indian patients

BACKGROUND

Deep vein thrombosis (DVT) is one of the most common complications of total hip (THA) and total knee arthroplasty (TKA). Though the reported incidence of DVT is very high, that of proximal DVT is low and that of fatal thromboembolism is very low. Hence the issue of prophylaxis for DVT remains controversial. The incidence of DVT is based on various studies in European and American populations. The Asian population is genetically and socially quite different from American and European populations, and the incidence of DVT can be quite different. Therefore a prospective study was initiated at our centre to determine incidence of DVT after THA and TKA in Indian patients.

METHODS

A prospective study was conducted on 60 hips in 45 patients and 46 knees in 26 patients who underwent THA and TKA respectively, without any known risk factors for thromboembolic disease. DVT was studied by preoperative and postoperative serial colour Doppler ultrasonography. No prophylaxis was given to any of the patients.

RESULTS

DVT was found in two patients who had undergone THA. No case of DVT was detected in any patient who had undergone TKA.

CONCLUSION

These results suggest that the incidence of DVT in Indian patients is very low and is not comparable with American and European populations. It is therefore not cost effective to advise prophylaxis in Indian patients undergoing THA/TKA who have no known risk factors for DVT.

Deep vein thrombosis after total hip arthroplasty in Indian patients with and without enoxaparin

PURPOSE

To study the incidence of deep vein thrombosis in Indian patients undergoing total hip arthroplasty with or without prophylaxis, and the effect of enoxaparin on deep vein thrombosis.

METHODS

The study covered a total of 50 hips in 40 patients who underwent total hip arthroplasty. Patients were assessed for deep vein thrombosis using Doppler ultrasonography. The hips were numbered and divided into 2 groups: the odd-numbered hips did not receive any thrombo-prophylaxis, whereas the even-numbered hips received 40 mg of enoxaparin subcutaneously, once a day for 2 weeks, until the time of discharge.

RESULTS

Deep vein thrombosis was not found in both groups. We found wound haematomas in 9 patients (all of whom were on enoxaparin) (p<0.05), superficial infection in 2 patients (one on enoxaparin, one not), and local bruising in 4 patients (all of whom were on enoxaparin). Major haemorrhage did not occur in any of the cases.

CONCLUSION

The incidence of deep vein thrombosis in Indian patients is very low compared to that in European and American patients. Enoxaparin failed to provide any advantage to the patients. It is therefore not advisable to give prophylaxis/low-molecular-weight heparin for deep vein thrombosis to patients undergoing total hip arthroplasty without any risk factors.

Complete compression ultrasound for the diagnosis of venous thromboembolism

PURPOSE OF REVIEW

Since its first appearance in the 1980s, venous ultrasound has increasingly gained interest of both clinicians and researchers. However, a majority of authors currently are convinced that venous ultrasound has inherent limitations that preclude it from safely ruling out distal deep vein thrombosis (DVT) in symptomatic patients and from detecting proximal and distal DVT accurately in asymptomatic patients. The aim of this review is to present recent lines of evidence indicating that venous ultrasound has developed beyond these limitations.

RECENT FINDINGS

The major development does not arise from technical progress of imaging but from standardizing the examination procedure. The most efficient protocols now focus on B-mode sonography only but extend the examination to the paired deep calf veins and the calf muscle veins. For such an examination protocol, the term complete compression ultrasound (CCUS) has been coined. Interobserver variability of CCUS resembles that of venography, as do the technical failure rates. By means of a CCUS protocol, the diagnostic work-up of patients with suspected DVT can be simplified significantly. Studies in asymptomatic patients indicate that CCUS has the potential to generate valid data in prevalence and incidence studies and in intervention trials.

SUMMARY

Complete compression ultrasound protocols are ready for implementation into clinical practice for diagnosing patients with symptomatic DVT. Research has already benefited from CCUS and benefits further with an increasing number of CCUS-driven trial designs. However, the value of a CCUS protocol critically depends on sound training and on strict compliance with all its details.