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Modern concepts in hand orthotics
D.
1
McDOUGALL
Dundee Limb Fitting Centre, Dundee
This p a p e r attempts t o describe some of the
principles a n d objectives in the orthotic
treatment of h a n d disabilities. T h e a u t h o r ' s
experience over m a n y years h a s been used in
t h e design of a variety of orthotic devices while
considering the following criteria:
Function
T h e device should place the h a n d in a
functional position, t h u s permitting immediate
use of any residual capability and also placing
the h a n d in the optimal position to p r o m o t e
recovery.
cold. T h e attitude of 40 degrees of flexion of
the distal end p o r t i o n prevents the orthosis
from slipping.
Vitrathene a n d polypropylene m a y also be
used; however, b o t h require a former for t h e
moulding process. Experience with this orthosis
t o date has proved it very effective in reducing
the final deformity, but further evaluation is
required.
Effectiveness
T h e device should be capable of effecting
relief of the symptoms.
Adaptability
T h e device should be capable of a d a p t a t i o n
t o fit a reasonable range of patients.
Adjustability
It should be possible to adjust the device to
compensate for the changing condition of the
h a n d during treatment.
Fig. 1. For Boutonniere injury (1) Type: passive.
Material: Prenyl. Function: PIP joint in extension,
D I P joint in flexion, 40 degrees approximately.
Comfort
Boutonniere injury orthosis (2)
T h e patient is m o r e likely to co-operate in a
comfortable splint.
T h e distal a n d proximal volar plastic t r o u g h s
are linked by parallel spring steel r o d s of 18
S W G wire. T h e dorsal trough is positioned
distally for ease of application of the orthosis.
Once the finger has been introduced t h e dorsal
trough slides into position over the proximal
interphalangeal joint, completing a three-point
pressure system (Figure 2).
Aesthetic
Appearance
These points will be illustrated in the follow­
ing series of figures.
Boutonniere injury orthosis (1)
This orthosis (Figure 1) m a y be formed by
direct application using Prenyl. This material
has the advantage of being easily adjusted after
immersion in h o t water a n d then setting in
A full Celadex ring is required distally if a
position of 40 degrees of flexion of the distal
segment of t h e finger is required. W h e n t h e
orthosis is applied t o the lateral aspect of t h e
finger it corrects deviation. It has also been
used in the treatment of a mallet finger.
Previously published in The Hand 7 : 1 , 58-62.
Fig. 2. For Boutonniere injury (2) Type: passive.
Material: Celadex-spring steel. Description: slidelock. Function: extends IP joints.
Ulnar deviation orthosis
This simple type of orthosis is easily fab­
ricated. T h e orthosis functions by using the
ring finger as a stabiliser, t h u s checking the
ulnar drift of the little finger (Figure 3). T h e
open-ended configuration is a d o p t e d to aid
application a n d removal. T h e orthosis can be
used for an ulnar nerve lesion or for a n injury
of the metacarpal joint, rather t h a n in the
r h e u m a t o i d arthritic.
Fig. 4. For recovery phase of minor finger injury.
Type: dynamic. Material: Celadex-spring steel.
Function: resists flexion IP joints, assists extension
IP joints.
Orthoses for thumb opposition
A three stage orthotic a p p r o a c h t o t h e
treatment of the hemiparetic child is d e m o n ­
strated.
The long opposition orthosis (Figure 5 left).
T h e long opposition orthosis incorporates
the wrist a n d metacarpals a n d can be fab­
ricated in the clinic. T h e t h u m b p o r t i o n m a y
be omitted while the m a i n wrist unit is posi­
tioned manually then immersed in cold water
t o set. A c a p unit t o abduct the t h u m b m a y b e
added later. If preferred the two c o m p o n e n t s
m a y be formed in the reverse order.
Fig. 3 . For ulnar deviation. Type: passive. Material:
Celadex. Function: adducts to mid-line (positioned
by adjacent finger).
Alternatively, the orthosis m a y be fabricated
o n a positive cast a n d o n some occasions a
master cast may be used. T h e p r o d u c t i o n of a
plaster of Paris negative can present s o m e
difficulties with the small child.
Minor flexion contracture orthosis
T h e transparent Celadex plastic saddle is
found t o be cosmetically acceptable (Figure 4).
F o r some patients, especially female, this
factor is of great importance a n d , if it results
in increased co-operation o n the p a r t of the
patient, it will undoubtedly assist recovery
from the injury. Once the patient's confidence
has been gained, further treatment m a y be
e m b a r k e d u p o n if the contracture requires a
stronger dynamic device. This orthosis can be
used o n social occasions a n d also during w o r k
t o maintain some degree of extension when
m o r e active splintage is inconvenient o r
impracticable.
The short opponens orthosis (Figure 5 centre).
This orthosis incorporates the metacarpals.
It is important to maintain the seating o n the
entire lateral aspect of the distal p a l m a r crease
extending proximally. This provides increased
comfort t o the wearer. T h e Velcro fixation
should be placed at the angle which provides
the most effective fixation.
The thumb-cap
right).
opposition
orthosis
(Figure 5
T h e t h u m b - c a p opposition orthosis is the
final stage of this orthotic treatment p r o g r a m m e .
A n o p e n - t h u m b unit can be used which gives
Fig. 5. For thumb opposition. Three stage orthotic approach. Left, long-incorporating wrist. Centre, shortincorporating metacarpals. Right, thumb cap. Type: passive. Material: Prenyl. Function: maintains opposition
of thumb.
additional freedom;
cause difficulty with
depend o n the type
normally acceptable
small a n d permits
movement.
however, this can also
pressure. T h e choice will
of patient. This unit is
to the patient as it is
an increased r a n g e of
In the production of this device (Figure 6)
it is necessary to measure a n d cast the h a n d and
t o fabricate the orthosis o n a former since the
cemented joints require time t o set. Once again
the properties of Prenyl m a k e it extremely easy
t o m a k e adjustments in the clinic. If the
orthosis is being used for a n extended period,
however, a m o r e rigid plastic is used.
This piece of a p p a r a t u s h a s been found
aesthetically pleasing t o the patient. It assists
those w h o grasp objects, such as sacks, t o
perform their daily tasks. It has been used in
Fig. 6. For injuries of ulnar nerve. Type: passive.
Material: Prenyl. Description: knuckle-duster.
Function: prevents clawing, harmonises movement.
Control by middle and index fingers.
Fig. 7. For injuries of ulnar nerve. Type: dynamic.
Material: malleable metal—Plastazote—No. 20
SWG spring steel. Description: ulnar intrinsic.
Function: assists flexion MP joints, resists extension
IP joints. (Palmar bar adjustable).
Orthosis for injuries of ulnar nerve
the early stage of t h e treatment of ulnar nerve
lesions t o b e followed by a lively type of
orthosis (Figure 7) a n d also in t h e reverse
sequence.
Orthoses for correction
flexion deformity
and prevention of
A n example of the use of these orthoses is in
the treatment of D u p u y t r e n ' s contracture. T h e
m o d u l a r design of these orthoses is of con­
siderable value when springs of varying tension
are required. T h e chassis is malleable t h u s
enabling precise fitting at t h e m e t a c a r p o ­
phalangeal joint a n d o n the p a l m a r aspect.
The single-finger orthosis (Figure 8 t o p ) is a
modification of t h e Exeter armchair orthosis.
This dynamic device is m a d e in three sizes t o
cover t h e adult range. This m e a n s that t h e
patient c a n b e fitted in t h e clinic enabling
treatment t o commence immediately. A similar
range is available for the treatment of children.
W h e n difficulty is experienced in maintaining
the position of t h e chassis o n t h e proximal
segment it m a y b e necessary t o extend t h e
saddle t o enclose this segment m o r e completely.
This is most c o m m o n l y encountered with t h e
small finger. This type of device can be p r o d u c e d
in multiples for application t o t w o o r m o r e
fingers (Figure 8 centre a n d b o t t o m ) . O t h e r
orthoses of a similar design h a v e utilised
springs of a shorter length. T h e end of a spring
with a short leg will m o v e in t h e p a t h of a
circle generated by t h e coil of the spring alone.
T h e natural p a t h of t h e t w o distal phalanges
moving from flexion into extension is t h a t of an
involute. (Figure 9).
Fig. 9. Involute path of finger tip from flexion to full
extension.
If a spring with a longer leg is utilised
bending will take place in t h e leg a s well a s
the spring coils. T h e combination of the m o t i o n
occurring in t h e leg a n d in t h e coils of t h e
spring results in a m o r e accurate copy of t h e
actual anatomical m o t i o n of the finger.
Fig. 8. For correction and prevention of flexion
deformity. Top, single finger orthosis. Centre and
bottom, multiple finger orthoses. Type: dynamic.
Material: malleable metal-Plastazote-spring steel.
Description: armchair (modified Exeter). Function:
assists extension I P joints, resists flexion IP joints
(spring adjustable).
BIBLIOGRAPHY
BUNNELL, S. (1948). Surgery of the hand. 2nd ed.
122, 128, 131. J. P. Lippincott Co., Philadelphia.
W Y N N PARRY, C. B. (1973). Rehabilitation of the
hand. 3rd ed. 63, 240. Butterworths, London.
RANK, B. K . , WAKEFIELD, A. R. and HUESTON, J. T .
(1973). Surgery of repair as applied to hand
injuries. 4th ed. 266. Churchill Livingstone,
Edinburgh and London.