Stroke is one of the top medical conditions resulting in high mortality among patients in
hospitals, where complications related to immobility such as deep vein thrombosis (DVT)
and/or ankle joint contracture can affect patients in their road to recovery. Patients may
often take months or even years to fully recover their limb functions, where certain
activities of daily living cannot be easily achieved prior to recovery. In the case of the
affected lower limbs, immobility can affect common activities such as getting out of bed
resulting in bedridden. Bedridden is also highly susceptible to the vicious cycle which
developing ankle joint contracture and DVT.
In severe DVT cases, the blood clots in the deep veins can dislodge into the bloodstream and
circulate in the whole body. There is a chance to occlude the arteries in the lungs, leading
to pulmonary embolism (PE). Venous thromboembolism (VTE), including DVT and PE, occurs at an
annual incidence rate of 0.75-2.69 per 1000 individuals worldwide; this incidence rate
increased to 2-7 per 1000 for individuals aged > 70 years (ISTH Steering Committee, 2014).
Among those diagnosed with DVT, 10-30% dies within 1 month of diagnosis (Beckman et al.,
2010), and 600,000-800,000 people die from DVT worldwide annually (worldthrombosisday.org),
which equates to approximately 1 DVT-related death per minute.
Current treatment approaches include pharmacological prophylaxis can be often used as the
blood thinner to prevent blood clot development. Low-dose anticoagulation reduces the
incidence of VTE, however, the benefit can be often offset by haemorrhagic complications
which can lead to death, especially for patients suffering from haemorrhagic stroke (Roderick
et al., 2005).
Other non-invasive treatment or mechanical prophylaxis, such as intermittent pneumatic
compression (IPC) and anti-embolism stockings, have some efficacy in preventing DVT based on
clinical reports (Mazzone et al., 2004; Caprini, 2010); however, these devices do not prevent
ankle joint contractures as their action mechanism is related with passive compression and
decompression of lower limb muscles without the actual mobilization of joints. Approximately
50% of all stroke patients develop at least one contracture within six months of stroke (Li
et al. 2012). Once the ankle joint contracture developed, it can exacerbate pedal edema and
fluid retention, and hamper proper joint movement, which is indispensable for regaining
ambulatory function and quality of life. These patients usually have to rely on regular
physiotherapy sessions that provide therapist-assisted ankle exercises to prevent ankle joint
contracture and reduce the risk of DVT. However, given growing manpower constraints and a
greying global population, there is an increasing workload on physiotherapists, resulting in
insufficient time to complete their physiotherapy routines.
This study is important for the following reasons:
To investigate the efficacy of the VACOM system in providing assisted ankle movement and
promoting lower limbs venous return for stroke patients in the hospital rehabilitation
setting.
This study intends to 1) observe the ankle joint mobility and flexibility by using the
range of motion measure, 2) monitor the presence of blood clots in lower limbs by using
compression Duplex ultrasonography, 3) evaluate the functional recovery by providing
early mobilization in the bed.
To study the economic impact of the VACOM system in the current healthcare system by
collecting the survey forms and statistical data.
To examine the cost-effectiveness, such as healthcare workload reduction, the
probability of the intervention being cost-effective, etc.
To generate evidence on this innovative device and further deploy it in clinical
practice.
The automated robot-assisted ankle exercise solution (Venous Assistance and Contracture
Management System, VACOM) aims to mimic therapist-assisted on bed passive ankle exercises to
preclude the development of ankle joint contracture and facilitate venous flow in lower
extremities to reduce DVT risk.
The VACOM uses soft pneumatic extension actuators, which is capable of providing
robot-assisted ankle exercises, specifically dorsiflexion-plantarflexion and
inversion-eversion movements. Through these natural movements to improve blood flow and
venous return and maintain ankle joint flexibility. Furthermore, it can facilitate and
stimulate the neurologic recovery in walking by early mobilization.
The investigators will conduct a multi-site clinical trial on around 100 stroke patients
across different hospitals and healthcare institutions in Singapore to establish the efficacy
of our soft robotic system (VACOM) in preventing ankle joint contracture and reducing DVT
risk. Importantly, to investigate the effect and impact of the current healthcare system on
the cost-effectiveness and workload reduction for the healthcare staff.
The Investigators hypothesize that the Venous Assistance and Contracture Management (VACOM)
system can improve ankle range of motion (ROM) and flexibility by preventing ankle
contracture while reducing the risk of DVT incidence among stroke patients. It might have a
better outcome than using IPC alone. Additionally, through early ankle mobilization,
rehabilitation can be optimized to achieve better neurological recovery.