Prosthetics and Orthotics Internarional, 1984, 8.

33-38

The technique of reciprocal walking using

the hip guidance orthosis (hgo) with crutches
P. B. BUTLER, R. E. MAJORandJ. H. PATRICK
Orthotic Research and Locomotor Assessment Unit.
The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry.

Abstract theoretically more efficient form of walking. The

An orthotic method of providing reciprocal orthoses provided to achieve these forms of gait
walking for high thoracic levels of paralysis is are long-leg calipers for the lower levels of
detailed. The essential features of the hip lesion, generally used in traumatic paraplegic
guidance orthosis are described, as well as the adults, and body brace/calipers, most commonly
basic muscle requirements for this form of used in congenitally paraplegic children. The hip
walking (shoulder, arm and hand function plus guidance orthosis (hgo) (Rose, 1979; Major et
Latissimus Dorsi). The walking sequence is al, 1981) is now becoming available and is
described at each stage under the three main applicable to both groups of patients (Fig.1.).
headings: mechanics, muscle action and hip Swing-through gait using long leg calipers has
guidance orthosis reactiowto build a complete been the subject of biomechanical analysis
picture of the walking process. The importance (Abramson, 1949) in which attention was drawn
of considering the input made by the patient in to orthotic function and user (patient) input.
addition to the purely mechanical orthotic However, this form of gait with unstable hips,
contribution is illustrated.

Introduction
Orthotics has, for many people, the aura of
being an empirical science. This may be true, not
only in that mechanical principles are seldom
used in the design of orthoses, but more
particularly in that the contribution made by the
patient in combining with the orthosis to make a
functional system is often ignored. An example
of such an empirical system is the provision of
body brace and calipers (HKAFO, or traditional
“full set”) to provide walking function in total
paraplegia.
When considering walking in complete
paraplegia above L1, the choice lies between
swing-through gait and reciprocal (step-by-step)
walking. The latter, by reducing the vertical
excursion of the centre of mass, can provide a
~ ~ ~~~

All corres ndence to be addressed to Mrs P. Butler,

Orthotic gsearch and Locomotor Assessment Unit,
The Robert Jones and A p e s Hunt Orthopaedic
Hospital, Oswestry, Shropshue,SYlO 7AG, U.K. Fig. 1. Hip guidance orthosis.

33
34 P. B. Butler, R . E. Major and J . H . Patrick
tends to require high energy input. Reciprocal The current design uses an aluminium alloy
gait can be obtained in long-leg calipers but is tubular and channel section body brace to
seldom achieved by patients with lesions above provide a rigid lightweight structure. A support
T12. in part due to the energy cost and the slow point on the chest is provided by a leather chest
mode of progression, Body bracelcalipers can strap with a seat belt fastening for easy fixation,
also be used for reciprocal walking. The hip and on the buttocks by a polypropylene support
hinges are used only for sitting and when they are band attached directly to the bearing housing.
locked for walking the orthosis restricts desirable The user's shoe rests on a shoe plate which is
flexion/extension. The hgo provides stability and provided with a rocker section at heel and toe.
control of the hip joints, thus allowing reciprocal The foot and shoe are held in place by a strap
walking in complete paraplegia, including high with a simple latch fastening enabling the user to
level lesions. retain normal footwear. The shoe plate is fixed
This paper outlines the design and principle of to the caliper section, with the appropriate
operation of the hgo from both the mechanical amount of dorsiflexion. The knee is held in
and user viewpoint. extension by a simply latched padded strap
reacted by the posterior thigh band and a vertical
Hip guidance orthosk description extension on the rear of the shoe plate. Knee
This orthotic system can provide low energy joints are provided, and both these and the hip
reciprocal ambulation with crutches for both joints release to allow the user to sit.
children and adults with spinal cord lesions The limited flexion/extension range at the hip
between T1 and L1 (Fig. 2.). ensures that step length is controlled. In some
The essential features of the orthosis are: cases the physiological extension stop of the hip
i) A rigid body brace which helps maintain the may operate before the orthotic stop.
relative abduction of the legs during the
swing phase of the gait cycle. Muscles involved in hip guidance orthasis
ii) A hip joint with a limited flexion/extension Walking
range and friction free operation. The following provides a brief guide, for those
iii) Stabilization of the knees and ankles. not familiar with anatomy, to the function of the
iv) A shoe plate incorporating rocker sole. major muscles involved in hgo walking.
v) Simple fastening arrangements of the Latissirnus Dorsi: this large muscle acts when
'
orthosis to ease application and removal. the flexed arm is extended against resistance
The addition of crutches and training in the until the arm reaches the plane of the body; it
total use of the hgo completes the system. also acts as a tie between the shoulder and the
pelvis on the swing leg side.
Pectoralis Major: acting as a whole, the muscle
n adducts the humerus; the lower fibres act in
conjunction with Latissimus Dorsi.
Deltoid: is also capable of acting in parts or as a
whole; the rearmost fibres co-operate with the
Latissimus Dorsi; it acts to steady the shoulder; it
acts as an abductor of the shoulder joint.
Trapezius: assists in steadying the scapula and
maintains the level and poise of the shoulder.
Triceps: the principal extensor muscle of the
elbow.

The mechanics of wallcing using the hip guidance

orthosiswith crutches.
In any efficient mode of ambulation there is a
V constant exchange of energy between the
potential and kinetic states. Therefore any
Fig. 2. Hip guidance orthosis can provide low energy
reciprocal ambulation for patients with spinal cord discussion of the forces involved must include
lesions between T1 and L1. inertial forces to be complete. The complete
 Technique of hgo walking 35

Fig. 4. Hgo walking, stage 2. Right crutch strike,

commencement of lateral movement to right.
Fig. 3. Hgo walking, stages 1-5 anterior and lateral.
Key- 1 ground reaction forces. 0 essential hgo
reaction forces. w selected rotations. This work has been confirmed by
active muscles. electromyographic studies of hgo users.
sequence for one step of hgo walking is Stage 2. Right Crutch Strike. Lateral movement to
illustrated in Figure 3. In the following right commencing. (Fig. 4)
description of ambulation using the hgo the cycle Mechanics. Most weight is transmitted through
will be described from Right Crutch Strike (Fig. the right foot. The right crutch is positioned well
4)but the reader is advised to follow the full cycle forward, providing a small, stabilizing reaction.
and then return to Stage 1, Right Heel Strike, in The left crutch is positioned slightly ahead of the
order to understand fully the nature of these left toe pushing down and back. This starts to tilt
inertial forces. the user to the right to clear the left leg. Forward
It should be noted that not all users pass momentum of the trunk gained from the
through the phase of gait described by Stage 4 previous step, assisted by the rearward left
but will go from Stage 3 straight to Stage 5. The crutch forces will cause the right hip to move
user here described is a “Group 111” user (see through the “uphill” phase over the right stance
Classification of hgo users), those omitting the foot (Fig. 5).

r
Stage 4 being Group 11.
Note: In the description of muscle action it is
accepted that the muscles of the hand and arm n
are used throughout, as are the small muscles of
the shoulder and Serratus Anterior. Their action
is not individually described. The muscle action
of moving the crutch forward is also not detailed,
the description being confined to the muscles
directly involved in producing ground reaction
forces. A full analysis of ground reaction forces
may be foundin thepaperby Majoret al, (1981).
Inertial forces are only shown where they are
essential to an understanding of the mechanics.
In discussing hgo action, it is accepted that
stabilization of the lower limb and control of hip
adduction are functional at all times.
Descriptions are limited to those where reaction
forces produced by the device are essential to Fig. 5 . Crutch force and trunk momentum move the
hip “uphill”. Potential ener is returned in the
comprehension of hgo function. “downhill” prase.
36 P. B . Butler, R. E. Major and J . H . Patrick

Fi .6. Hgo walking, stage 3. Early to mid swing of the Fig. 8. Hgo walking, sta e 4. Peak of right lateral tilt
lei! foot. Lateral tilt to right; rotation of the trunk in (Group 1% user only).
the sagittal plane.

Muscle action. The forces on the left crutch are Stage 3. Early to mid-swing of leftfoot. Laleral tilt
produced by the left Triceps and shoulder girdle to right. Rotation of the truhk in thesagittalplane.
depressors (Serratus Anterior, Pectoralis Minor, (Fig. 6 ) .
lower fibres of Pectoralis Major) with Mechanics. An increase in vertical forces on
stabilization of the shoulder girdle by the right the left crutch reduces the load transmitted
shoulder girdle depressors and the Deltoids. through the right foot, but the backward force is
Extension of the shoulder (rearward crutch increased. Since the left arm and crutch are
force) is produced by Triceps, Pectoralis Major grounded and cannot move backwards relative
(sternocostal part, until the arm reaches the to the floor, an attempt to extend the shoulder
plane of the body) and the left Latissimus Dorsi, must result in trunk rotation in the sagittal plane,
whose action also assists commencement of leg moving the pelvis forward. This in turn will pro-
clearance by acting as a tie between the shoulder duce extension of the right (stance) hip (Fig. 7).
and pelvis (see Stage 3: muscle action). As the body moves up over the right foot the trunk
Orthotic reaction. An essential feature of the momentum decreases. A twisting moment is
above is that the hgo should provide a reaction produced by the horizontal components of force
force on the right chest wall. acting at the right leg and left crutch and this is
stabilized by the small force through the right
crutch.

P Muscle action. The vertical force in the left

crutch continues to be produced by the Triceps
and shoulder depressors. Latissimus Dorsi
provides
i) forward motion of the pelvis because the
arm position is fixed relative to the floor
which in turn produces extension of the
stance hip by assisting the forward inertial
forces of the pelvis.
ii) Latissimus Dorsi also has an additional
function acting as a tie between the crutch
supported shoulder and the pelvis. Thus
when the hgo user is in mid swing the muscle
assists the structure of the hgo in keeping
Fig. 7. Left, the normal effect of extending the the swing leg clear of the ground and
shoulder is to move the arm relative to the trunk. preventing adduction of the hgo structure
Right, the introduction of a ground reaction (crutch)
stabllizes the arm,thus producing truncal movement. about the stance hip.
 Technique ofhgo walking 31

Orthotic reaction. The forward movement of n

the pelvis relative to the stance foot will carry the

hip hinge forward in space, whereas the shoulder
girdle makes a relatively small forward
movement.
The top rear band ensures that the body brace
maintains the correct position relative to the
trunk. Reaction forces on the right chest wall will
be produced as described in Stage 2 above.
Stage 4. Peak of right lateral tilt (Group I l l user
only). (Fig. 8 ) .
Mechanics. The left crutch force is transferred
to the right foot allowing the left crutch to be
removed from the ground and moved forward.
The right crutch is still providing a small control Fig. 9.Hgo walking, stage 5 . Left heel strike.
force. The lateral rocking that has been imposed
through the left crutch provides sufficient Orthotic reaction. As Stage 4.
momentum to cany the centre of gravity towards The left crutch is then repositioned in front of the
the right leg support but not past it. In time this left foot ready to begin the sequence for the next
motion will be reversed and the body will drop step.
onto the left leg which should have achieved the
maximum flexion permitted by the hgo. The Classification of hip guidance orthosis users
forward truncal momentum will have increased The precise mode of hgo walking varies from
due to the “downhill” phase of moving over the user to user and may alter with time in an
stance foot. individual user. It is valuable to observe and
Muscle action. There is minimal muscle classify these variations for two reasons:
activity at this point. The left crutch will be 1. Awareness and understanding of different
moved forward. There is sufficient activity of the walking styles is extremely helpful in gaining
right Triceps and shoulder girdle to stabilize the total understanding of the mechanics of hgo
right arm against the small control forces being walking.
generated. 2. As the user gains familiarity and experience
Orthotic reaction. The fact that there is very with hgo walking, he may progress from one
little muscular activity implies that the hgo group to another. Thus classification forms a
structure is not reacting muscle force, but is simple guide to user function and provides a
simply resisting adduction and limiting hip means of monitoring this function.
flexion. There are four groups of hgo user:
Group I These are not efficient users of the
Stage5. Lefi heelstrike. (Fig. 9). hgo and demonstrate inability to perform hgo
Mechanics. Body weight is transmitted walking competently. Their walking is
through the right foot but transfer to the left foot characterised by hesitancy, uncertainty and high
is about to commence. This will be assisted by energy expenditure. The swing leg may not clear
the lateral momentum gained by rocking off the the ground adequately, or the user may swivel on
right foot. The right crutch is still providing a the stance leg. The walking aid may be either
small control force although this could be rollator or crutches.
increased to assist the rocking if required. At this This group of user will need help with their
point the trunk has maximum forward problems and it is worthwhile
momentum gained from the “downhill” phase. 1. Checking the fit of the orthosis (following
Muscle action. The only muscle action routine mechanical inspection of the hgo)
required is to provide the control force on the 2. Training the user further to eradicate
right crutch, with increase to assisting force if problems.
necessary to rock onto the left foot. This Group I1 In contrast, these users have a
function is fulfilled as before by the right Triceps rhythmical form of gait with low energy cost.
and shoulder depressors. They perform hgo walking as described (see
38 P. B. Butler, R . E. Major and J . H . Patrick

mechanics of walking using the hgo, but omitting It is obvious, therefore, that to perform this
Stage 4). Thus they always maintain at least three mode of walking the walking aid must be
points of contact with the ground, the flow of crutches to achieve two point contact. Because
walking being right heel strike, right crutch these users are more proficient, they will usually
swing and strike, left leg swing and strike, left walk more quickly, and over a greater variety of
crutch swing and strike, right leg swing and strike surfaces than Group 11.
etc. These users will often demonstrate marked Group N Comparatively few users will be
truncal movement in the sagittal plane, which classified into this group. These users
increases as they become more vigorous walkers. demonstrate an assurance not shown in the
Speed of walking is not a factor in determining previous groups. The main feature of this mode
group of user and the walk may be quite slow but is the apparently random use of crutches. The
will be classified as Group I1 if the above factors crutches may be advanced simultaneously or at
are demonstrated. random intervals. These users have reached a
Group I1 walkers may use either rollator or very refined form of hgo walking, where their
crutches (rollator implying at least three point awareness and familiarity with walking enables
contact) and this group may be usefully them to inject forces to their own particular
subdivided further into those who use rollator (I1 needs, and to use inertial forces to greater
R) and those whose use crutches (I1 C). advantage. The first couple of steps in a walking
The majority of hgo users will be Group 11. sequence usually conforms to the previously
Group III These are the more experienced described pattern, and once in progress the more
users of the hgo who have developed greater random mode takes over. Obviously this mode
confidence and ability. Observation of their of walking is only achieved with crutches.
walking often reveals a pronounced side-to-side This group of users generally demonstrates an
sway as they walk. Close inspection reveals economy of truncal movement, which, although
that they include Stage 4 of the described present, is reduced in comparison to Groups I1
mechanics of hgo walking. Thus at one point and 111.
during each step they go to two point contact
only, using the foot and crutch on the same side REFERENCES
and it is this which is responsible for the
pronounced lateral (coronal plane) sway. These
users may also demonstrate sagittal plane truncal
ABRAMSON,
I
A. S. 1949). Principles of bracing in the
rehabilitation o the paraplegic. Bulletin of the
Hospital for Joint Diseases. 10, 175-182.
movement as in Group I1 but the effect of the
lateral movement often masks this. The flow of MAJOR,R. E.,STALLARD, J., ROSE,G. K. (1981).
walking is thus right crutch swing, right heel The dynamics of walking using the hi uidance
orthosis (hgo) with crutches. Prosthet. 8rtfbt. lnt.,
strike, right crutch strike, left leg swing, left 5. 19-22.
crutch swing, left heel strike, left crutch strike,
etc. (i.e. the crutch on the same side strikes after ROSE,G . K. (1979) The principles and practice
of hi uidance articulations. Prosthet. Orthot. lnt.,
the foot). 3.3B3.