Ambulatory Devices: Assessment and Prescription

Daniel Olufemi Odebiyi and Caleb Adewumi Adeagbo

#### Abstract

Injuries or disabilities associated with the lower extremities and aging frequently result in ambulation difficulty and this usually necessitates the prescription of ambulatory assistive device (e.g., cane, crutch and walker) in an attempt to restore locomotory function. Ambulatory devices are orthotic devices that provide support, stability and balance for users to able to move from one point to another. Users can progress or retrogress from one ambulatory device to another while some are permanently fit on a particular device throughout lifetime. The progression is dependent on the medical condition, user's abilities, user's anthropometric and environment. Physiotherapist prescribes ambulatory device to users and helps with the fitting and proper use of the ambulatory device. A correct prescription and well fitted ambulatory device minimize functional limitation and promote functional ability and improve quality of life. Incorrect prescription, fitting and use of ambulatory device may result in early fatigue, frustration, fall and damage to blood vessels, muscles or nerves.

Keywords: ambulatory devices, walker, crutches, cane

#### 1. Introduction

Ambulatory devices are mobility devices that assist in transfer of user from one point to another. Ambulatory devices require active participation of users during mobilization while mobility devices requires passive participation of users. Mobility devices are stretchers and wheelchairs [37].

Ambulatory devices are used by people with musculoskeletal impairments, neurological deficit and older people in order to be independent or decrease dependency on care-givers and health care practitioners. Ambulatory devices are orthotic devices used for support (i.e., augmentation of muscle action and/or reduction of weight-bearing load), maintaining stability and balance with the aim of transferring individual with ambulatory difficulty from one point to another due to injury or disability [13].

Many factors predispose an individual to use ambulatory devices. These factors may be aging, congenital, medical or traumatic. Congenital factors include structural deformities that are present at birth, while traumatic factors are as a result of accident. Medical factors are as a result of diseases which can lead to amputation, limb discrepancies, muscle weakness and loss of balance. Users can progress or retrogress from one ambulatory device to another while some are permanently fit on a particular device throughout lifetime.

There are many ambulatory devices developed to suit diverse presentations from difference medical or surgical conditions and these include parallel bar, walker, crutches and cane. Each of the ambulatory device has advantages and disadvantages that enhance their prescription and usage. Therefore, clinicians need to have a good understanding of these ambulatory devices to be able to recommend the ideal ambulatory device for the user [3, 10].

• Helps to correct poor posture: the support provided by ambulatory devices creates a platform that enhances good posture habit among users when the

• Helps to reduce risk of fall: assumption of good posture arising from increased

supporting base of users help to reduce the risk of fall among users.

• Helps to reduce pain on the affected limb: the use of ambulatory support encourages body weight of the users to transferred to the ambulatory devices.

• Helps to augment muscular strength of the trunk and of the affected lower

Ambulatory devices are aids made of durable and non-malleable materials for assistance during walking and standing. The main function of ambulatory device is to reduce the amount of weight bearing on the weak (or affected) lower limb or totally eliminate weight from the lower limb by transmitting the body weight from the upper limb to the floor through the ambulatory device [8]. Weight bearing status of ambulatory device user is the amount of weight the user put on the weak (or affected) lower limb during ambulation. The weight bearing status can be measured in grades or percentages. The amount of weight bearing on the weak (or affected) lower limb is determined by the user medical history, weight bearing capacity as can be tolerated and functional ability of the weak (or affected) lower limb [11]. The weight bearing status available among ambulatory device users

Non-weight bearing (NWB): the affected lower limb will not touch the floor during ambulation (i.e., no weight is borne on the affected lower limb) [11]. The percentage of body weight transmitted to the floor, through the affected lower limb

Touch down weight bearing (TDWB): this is also known as toe touch weight bearing (TTWB). Here, the foot or the toes touch the floor but no weight is transmitted to the floor through the affected lower limb involved. Thus, the percentage of body weight transmitted to the floor, through the affected lower limb is also zero

Partial weight bearing (PWB): here, a little amount of weight is transmitted to the floor through the affected lower limb. The percentage of body weight transmitted to the floor can range between 1 and 50% [11]. During the training stage, two body weighing machines/apparatus can be used to accurately determine the percentage

Weight bearing as tolerated (WBT): the user of the ambulatory device determines

Full weight bearing (FWB): the affected/involved lower limb can bear the total weight of the body. The percentage of body weight transmitted to the floor through the affected lower limb can be 100% [11]. This type of weight bearing status is used

the amount of weight to bear on the affected/involved lower limb. The weight bearing status is totally dependent on the individual ambulatory device user and the percentage of body weight transmitted to the floor can range from 50 to

body that may borne on the affected lower limb (Figure 4).

to build confidence with the ambulatory device user.

right ambulatory device is selected and properly fit.

Ambulatory Devices: Assessment and Prescription DOI: http://dx.doi.org/10.5772/intechopen.89886

limbs [21].

2. Ambulatory devices

is zero (0)% (Figure 2).

(0)% (Figure 3).

100% [11].

61

(apart from cane) are as described below:

Prescription of ambulatory device is determined by the user's anthropometric parameters (body weight, height and body mass index), user's abilities (skill), user's needs and environment. Other factors that influence the prescription of ambulatory devices include; weight bearing status, the degree of support or assistance the device can offer, the coordination of the user, range of motion available at the involved joints, balance, stability, strength, and general condition of the user.

There are also body functions involved in determining user's capacity to use an ambulatory device, these are cognitive function, judgment, vision, vestibular function, upper body strength, physical endurance. Depending on severity, impairments in any of these functions could make it impossible for a user to safely use a device.

The prescription of any ambulatory device should specify the device most likely to maximize the user's function; the individual's goals and personal preferences must also be considered. Physiotherapists are licensed and help with the fitting and proper use of ambulatory device while other health practitioners can also recommend ambulatory devices. All ambulatory devices are made in different height and so user must be fitted in order to obtain the correct ambulatory device height [6].

The functions of ambulatory devices when properly use includes the following:


Figure 1. Increase of the base of support for a user of ambulatory device (crutches).

