Orthotics Flashcards
What is Orthotics?
The science that deals with the use of specialised mechanical devices to support or supplement weakened or abnormal joints or limbs.
What is an Orthosis?
An externally applied device (brace, splint, orthotic) that can improve function, reduce pain and/or prevent deformity
What is an Orthotist?
Registered health care professional who specialises in the assessment of the whole body for biomechanical problems, and if appropriate may prescribe, measure, fit or review an orthosis.
Why are the majority of orthotics made for the lower limb?
Due to the development of medicines.
List the types of lower limb orthotics available?
Foot orthosis Footwear AFO - ankle foot orthosis KO - knee orthosis KAFO - knee ankle foot orthosis HKAFO - hip knee ankle foot orthosis
What are the 3 common abnormal biomechanics problems with regards to the foot?
Valgus deformity
- everted frontal plane position
Varus deformity
- inverted frontal plane deformity
Equinus deformity
- plantar-flexed position in sagittal plane
What is a foot orthosis?
A moulded walking base used inside footwear (insoles, heel cups).
Is a foot orthosis always custom made for the patient?
No, it can also be pre-moulded.
What are the functional potentials of a foot orthosis?
- re-distribution and reduction of plantar pressures
- relieve pain
- improve function
- prevent structural deformity
- correct mobile deformity
- accommodate fixed deformity
- limit or prevent joint motion
The function of a foot orthosis depends on the deformity of the patient. What does this mean?
If the patient has a MOBILE deformity - the foot orthosis should CORRECT the deformity.
If the patient has a FIXED deformity - the foot orthosis should ACCOMMODATE the deformity.
What does a ‘mobile deformity’ mean?
The body part can be manipulated into a ‘normal’ alignment.
What does a ‘fixed deformity’ mean?
The body part cannot be manipulated into a ‘normal’ alignment.
What stages form the assessment phase of a patient for an orthosis?
1) referral info and relevant Hx
2) physical assessment (ROM, muscle powers, sensation, proprioception, circulation, muscle tone)
2) static and dynamic gait assessment
4) aims and objectives of patient and clinician
How is a mobile valgus foot deformity treated?
(everted in frontal plane)
1) manipulate the foot to a corrected position and hold the foot by applying 3 point forces (2 lateral, 1 medial)
2) insert a medial wedge on insole or footwear
How is a fixed valgus deformity treated?
(everted in frontal plane)
1) accept the foot position and accommodate to achiever greater stability
2) lateral wedge on insole or footwear
How is a mobile varus foot deformity treated?
(inverted in frontal plane)
1) manipulate the foot to a corrected position and hold the foot by applying 3 forces (2 medial, 1 lateral)
2) lateral wedge on insole or footwear
Is an equinus foot deformity usually mobile or fixed?
Fixed (can happen after a stroke)
How is a mobile equinus foot deformity treated?
(plantar-flexed in sagittal plane)
Manipulate the foot to a corrected position and hold the foot by applying 3 forces (1 under the foot, 1 into the anterior ankle, 1 behind the knee).
How is a fixed equinus foot deformity treated?
(plantar-flexed in sagittal plane)
accommodate the deformity by inserting a heel raise wedge which follows the contour of the foot whilst ensuring the knee isn’t made unstable.
If an equinus foot deformity is not adequately accommodated, what can happen?
Hyperextension of the knee.
How is a fixed varus foot deformity treated?
(plantar-flexed in sagittal plane)
Accommodate the deformity by inserting a medial wedge on the insole or footwear.
List the different types of footwear adaptations?
Heel raises
Wedges
Flares
Rocker soles
What are the uses of a shoe/heel raise?
To accommodate fixed equinus foot or leg length discrepancy.
What are the uses of shoe wedges?
To correct mobile or accommodate fixed varus/valgus foot.
What is the use of a shoe flare?
To increase stability from a varus/valgus foot.
What are the uses of a rocker sole on a shoe?
Increase stiffness of the sole
Increase toe spring
Shift the GRF posteriorly.
What is an AFO?
Externally applied device that extends from just below the knee, around the ankle and across the sole of the foot.
What are the functional potentials of an AFO?
- correction of the MSK system
- maintenance of a position
- assist motion about a joint
- resist motion about a joint
- protection
- improve walking speed and cadence
- reduce energy expenditure
What are the 4 different types of AFO?
solid AFO
posterior leaf spring AFO
varus/valgus control AFO
jointed AFO
(depends on patients functional loss/gait deviations)
In what ways can the mechanical characteristics of an AFO be altered once made?
increasing/decreasing medial/lateral trimlines
increasing/decreasing material thickness
changing cross section shape
adding reinforcement/stiffeners
material choice
Why is a heel height assessment important to be carried out with regards to an AFO?
Altering the heel height of shoes will influence the GRF around the knee and can increase or decrease stability.
What biomechanical principles is an AFO based upon?
lever arm moments
three point forces for correction
What 3 point forces are used in an AFO for a valgus ankle deformity?
1 lateral foot
1 lateral knee
1 medial ankle
What 3 point forces are used in an AFO for a varus ankle deformity?
1 medial foot
1 medial knee
1 lateral ankle
What is a KO?
Externally applied device that extends from mid-thigh to mid-calf.
Is a KO always custom made?
No, they can be pre-maufactured.
What are the functional potentials of a KO?
- relieve pain
- improve function
- prevent structural deformity
- correct mobile deformity
- limit or prevent joint motion
What motions can a KO control?
flexion hyperextension ant/post instability med/lat instability rotation
What are the most common reasons for fitting a KO?
OA
post-surgery
ligament injury
mild instability
Why must the deformity only be mild for a KO to be suitable?
Due to short lever arms.
What 3 forces are required in a KO to correct medial instability?
i.e. mild valgus deformity
1 medial knee
1 lateral thigh
1 lateral calf
What 3 forces are required in a KO to correct lateral instability?
i.e. mild varus deformity
1 lateral knee
1 medial thigh
1 medial calf
What 3 forces are required in a KO to correct hyperextension of the knee?
1 posterior knee
1 anterior thigh
1 anterior calf
What is a KAFO?
Externally applied device extending from the thigh to the foot.
What is a KAFO commonly referred to as?
A calliper
What are the functional potentials of a KAFO?
- correction of the MSK system
- maintenance of position
- assist motion about a joint/joints
- resist motion about a joint/joints
- protection
- improve walking speed and cadence
- reduce energy expenditure
What considerations must be taken into account to determine what type of KAFO should be prescribed for a patient?
patient age, weight, activity level general health occupation lower limb function goals and expectations upper limb function
What are the different types of appearance of a KAFO?
CONVENTIONAL
- metal and leather (heavy in weight and hard bearing)
COSMETIC
- thermoplastic (lightweight, durable)
What are the different materials which can be used for the side bars of a KAFO?
Steel
- heavy and hard bearing
Dural
- aluminium alloy
- softer and lighter material
What are the different types of knee locks which can be used for a KAFO?
Free
- no locking mechanism
Drop locks
- when the knee is in extension, gravity causes a ring to drop and joint to lock
Manual drop locks
- when the knee is in extension, a ring needs to be moved by hand to lock
Semi automatic locks
- when the knee is in extension, a spring activates a ring to lock
Bale locks
- bar or cord activated ring lock joint
Polycentric locks
- more than one joint centre
Spline joints
- incremented joint to allow fixed setting, can be used in contracture Mx
The KAFO is required to take the BW through the side bars, to reduce the weight through the leg. What are the 2 ways in design that this can be achieved?
Quad top
- ischial tuberosity rests on a ledge outside socket
Ischial containment
- ischial tuberosity rests within socket
What 3 forces are required in a KAFO to correct medial instability?
i.e. valgus deformity
1 medial knee
1 lateral top thigh
1 lateral ankle
What 3 forces are required in a KAFO to correct lateral instability?
i.e. varus deformity
1 lateral knee
1 medial top thigh
1 medial ankle
What is a HKAFO?
A KAFO with the addition of a hip joint and pelvic band
When is the use of a HKAFO indicated?
to stabilise the hip and lower spine in cases where the patient is weak or paralysed
Give an example of a HKAFO?
Hip guidance orthosis (HGO) - consists of bilateral KAFOs linked via specially designed low friction hip joints
What are the 2 general categories of upper limb orthotics?
Static and Dynamic
List the different types of upper limb orthotics?
finger orthosis hand orthosis WHO - wrist hand orthosis Elbow orthosis EWHO - elbow wrist hand orthosis shoulder orthosis
What is the most common static upper limb orthosis?
WHO - wrist hand orthosis
prevents movement at specific joints
When is a WHO used?
To prevent contracture development
What is a dynamic upper limb orthosis, how does it work?
The orthosis has springs and moving components, which holds the arm in corrected position while allowing active movements at specific joints.
