incidence of deep vein thrombosis in elderly Chinese suffering hip fracture is low without prophylaxis: A prospective study using serial duplex ultrasound, The

Journal of Orthopaedic Surgery, Dec 2004 by Chan, Y K, Chiu, K Y, Cheng, S W K, Ho, P

ABSTRACT

Purpose. To investigate the incidence of deep vein thrombosis (DVT) among elderly Hong Kong Chinese patients suffering from acute hip fracture and to analyse the risk factors associated with DVT.

Methods. A total of 100 consecutive Chinese hip fracture patients with a mean age of 80 years were investigated serially using duplex ultrasound scans preoperatively and at 1 week, 3 to 6 weeks, and 3 months postoperatively. No chemoprophylaxis or prophylaxis against DVT was given.

Results. 95 patients completed 3 duplex scans during hospitalisation; 5 (5.3%) of them were found to have developed DVT over the ilio-femoral venous segment. Of the 90 patients who had no DVT, 73 were reassessed 3 months after operation; one of them was found to have developed calf DVT. Older patients, chairbound or dependent patients, and patients living in institutions carried a higher risk of developing DVT.

Conclusion. This prospective study shows that the incidence of DVT developing after acute hip fracture in Chinese geriatric patients was low. We therefore do not recommend routine chemoprophylaxis for elderly patients with hip fracture.

Key words: Asian continental ancestry group; hip fracture; prospective studies; risk; ultrasonography; venous thrombosis

INTRODUCTION

Venous thromboembolic disease is a major cause of mortality and morbidity in Caucasian patients undergoing orthopaedic surgery. Stasis, hypercoagulability, and vessel wall injury (Virchow's triad) are the 3 major contributing factors to the pathogenesis of venous thrombosis. Any of these factors can be activated during and after a major surgical procedure or injury of the hip and pelvis. Deep vein thrombosis (DVT) over the iliac and femoral veins (proximal DVT) is the most common cause of pulmonary embolism. The incidence of developing pulmonary embolism secondary to proximal DVT varies from 35 to 50%.1

It is controversial whether the incidence of thromboembolic disease among Asian populations is as common as that among Caucasian populations. The incidence of DVT was reported as being 2.6% using I-labeled fibrinogen tests in Chinese patients who had undergone general surgical operations.2 Among Chinese patients suffering from hip fracture, a study using venography as the screening test reported that the incidence of DVT was 53.3% in 1980.3 In that study, the majority of DVT were located in the calf, whereas DVT proximal to the popliteal vein occurred in only 8.3% of the patients. In a Malaysian study in 1996, a 50% incidence of DVT in patients suffering from hip fracture was reported.4 In Korea, the incidence of DVT in patients undergoing major spinal surgery was only 1.3%.5 In a retrospective autopsy study conducted on Hong Kong Chinese in 1990, the incidence of significant pulmonary thromboembolism increased significantly from 0.58% during 1975-1979 to 2.08% during 1985-1989.6 In that study, 36% of the cases had surgery prior to death, 16% of which had undergone hip surgery.6 The incidence of pulmonary thromboembolism further increased to 4.7% for the period 1990-1994.7

Hong Kong, like many other modern cities in Asia, is now adopting lifestyles and dietary habits increasingly similar to that of the West. We are concerned whether the incidence of thromboembolic diseases among Hong Kong Chinese is consequently approaching the rate observed in Caucasian populations.

We aim to investigate the incidence of DVT among elderly Hong Kong Chinese patients suffering from acute hip fractures and to analyse the risk factors associated with DVT.

PATIENTS AND METHODS

In this prospective study, we recruited a total of 100 consecutive Chinese geriatric patients who had suffered acute hip fractures and were admitted to Queen Mary Hospital between January 1996 and July 1996. The mean duration between injury and operation of the patients was 5.3 days (range, 1-15 days). No chemoprophylaxis against DVT, elastic compression stockings, or foot pumps were used.

Exclusion criteria were patients who had a history of DVT, who suffered pathological fracture, or who had a known coagulation disorder. During the course of the study, 5 more patients were excluded. One of the 5 had liver disease with a deranged coagulation profile. The remaining 4 died before completion of the study. The causes of death were not related to DVT or pulmonary embolism. Postmortem of the deceased patients was not performed because the families did not consent to it. 95 patients completed the follow-up assessment and the screening using duplex ultrasound scanning during hospitalisation.

The mean age of the 95 patients was 80 years and the female-to-male ratio was 2 to 1. Of the patients, 48 suffered intertrochanteric femoral fracture, 8 suffered subtrochanteric femoral fracture, and 39 suffered femoral neck fracture. Standard orthopaedic operations were carried out including: dynamic hip screw fixation in 56 patients, hemiarthroplasty in 28 patients, intramedullary nail surgery in 2 patients, and multiple cancellous screw fixation in 9 patients. One patient treated with hemiarthroplasty had additional cement augmentation. Another patient treated with dynamic hip screw fixation had additional cerclage wiring performed.