بسم الله الرحمن الرحيم orthotics and prothetics. an orthosis (orthotic) is a...
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الرحيم الرحمن الله بسم
Orthotics and Prothetics
An orthosis (orthotic) is a device that is applied externally to a part of the body.
The word is derived from ortho, meaning straight. Orthoses are sometimes called orthotics
Brace: is a device that corrects irrigularities. Splint: usually used after surgry and does not allow
for movement.
The orthotist is the person who designs, fabricates and repair the orthotic device.
Indications for recommending orthotic devices:
To relief pain. To limit motion, immobilization after surgery immobilization after traumatic injury Compression fracture management Kinesthetic reminder to avoid certain movements. To correct deformity e.g. Scoliosis management To relieve symptoms of a disease by supporting or
assisting the musculo-neuro-skeletal system. To reduce axial loading, mechanical unloading To improve function in a certain segment of the
body.
Assist and improve movement and function Reduce muscle tone. Protect against injury. Provide proprioceptive feedback. Provide rest.
Design characteristics of an orthotic device :
Most important features include the following: Weight of the orthosis Adjustability Functional use Cosmoses Cost Durability Material Ability to fit various sizes of patients Ease of putting on (donning) and taking off (doffing) Access to tracheostomy site, peg tube, or other drains Access to surgical sites for wound care Aeration to avoid skin maceration from moisture
Duration of orthotic use:
It is determined by the individual situation. In situations where instability is not an issue, recommend
use of an orthosis until the patient can tolerate discomfort without the brace.
When used for stabilization after surgery or acute fractures, allow 6-12 weeks to permit ligaments and bones to heal.
Effects of the orthosis may lead to: Decrease pain Increase strength Improve function Increase proprioception Improve posture Correct of spinal curve deformity Protect against spinal instability Minimize complications Assist healing of ligaments and bones
Associated drawbacks of the use of an orthotic device:
Discomfort Local pain Skin breakdown Nerve compression Muscle atrophy with prolonged use Decreased pulmonary capacity Increased energy expenditure with ambulation Difficulty donning and doffing orthosis Difficulty with transfers Psychological and physical dependency Increased segmental motion at ends of the orthosis Poor patient compliance
Benefits of orthosis:
Improve function. Save energy. Increase endurance.
The main aim of orthotic intervention is to function without dis-function.
Disadvantages and limitations of orthoses.
Limit mobility and ROM of the joint. Restrict rotation around a joint. Movement is usually limited to certain direction. Weakness of other muscles in opposite direction. The device is exposing to wear and tear. It needs maintenance, care, cleaning, repairing,
and frequent changing of shoes.
Principles and considration for orthoses:
Orthosis should :
provide support and stability to the hip, knee and ankle joints. be designed to permit safe and effective ambulation by patients. Provide the need and requirements of the patient to support or to
mobilize. Correlate to the findings of tests & measurements. Correlate with pateint personality and the impact of device upon
him. Prevent the development of deformity and require modifications in
design. Orthosis is only one component of the treatment and is not the
whole treatment. Conserve the time and energy of the patient. The materials used should be light, sturdy and resistance to wear.
It should meet the functional requirements of the client. So each client should be evaluated individually.
Role of physical therapist Identify functional problems of the patient. Determine orthotic needs. Prescribe the orthoses according to each patient
problems and requirements. Evaluate orthotic adequacy. Teach the patient to don and doff the orthoses. Train the patient for proper use of the orthoses.
Maintenance of orthosis:
Orthosis should be simple and durable as possible.
Patient should be taught for: Cleaning the leather. Oiling the joints. Wash the orthosis if possible.
Types of orthoses
Temporarily orthoses: Used for certain time after injury or operation.
Permanent orthoses: Used for ever when there is muscle weakness, paralysis or deformity cannot be corrected.
Or,
Static orthosis does not allow movement.
Dynamic orthosis allows movement.
Common injuries, diseases and deformities that need use of orthoses
For discussion
MATERIALS
An orthosis can be constructed from metal, plastic, leather, synthetic fabrics, or any combination. Plastic materials, such as thermosetting and thermoplastics, are the materials most commonly used in the orthotic industry.
Plastics Thermosetting materials can be molded into permanent shape
after heating. They do not return to their original consistency even after being reheated. Thermoplastic materials soften when heated and harden when cooled.
Low-temperature thermoplastics can be fabricated easily and rapidly with hot water or hot air and scissors, but they are used mainly in low stress activities.
High-temperature (polypropylene) thermoplastics require higher temperature (150°C) to mold, but they are ideal for high stress activities.
Leather such as cattle hide, is used for shoe construction because it
conducts heat and absorbs water well. Rubber
Rubber has tough resiliency and shock-absorbing qualities.
Rubber is used for padding in body jackets and limb orthoses.
Metal Metals, such as stainless steel and aluminum alloys,
are adjustable, but they are heavy and not cosmetically pleasing.
Metals can be used for joint components, metal uprights, sprints, and bearings.
Selecting the appropriate material characteristics for fabrication of an orthotis device requires careful consideration of a number of factors
Strength: the maximum external load that can be sustained by a material.
Stiffness: the amount of bending or compression that occurs under stress. e.g. when greater support is required, a stiffer material is used; when a more dynamic orthosis is desired, a more flexible material is used.
Durability (fatigue resistance): the ability of a material to withstand repeated cycles of loading and unloading.
( selection of a material for orthotic appliances is based on the ability of the material to withstand the day-to-day stresses of each individual client.
Density: the greater the volume or thicker a material the more rigid and more durable. (this usually increases the over all weight of the orthosis.
Corrosion resistance: the material may be affected by chemical degradation. Most materials will exhibit corrosion over time, metal will rust and plastics become brittle. Contact with human perspiration and environments such as dirt, temperatures and water accelerate the wearing effect on the materials. Knowing the client‘s daily environment can assist in material selection.
Ease of fabrication: the equipments needed for fabrication of orthosis
Biomechanichal principles of orthotic design
The biomechanical principles of orthotic design assist in promoting control, correction, stabilization, or dynamic movement.
All orthotic design are based on three relatively principles:
These principles are:
Pressure equilibrium The lever arm
The pressure principle the pressure should be equal to the total force per
unit area.
Force P = ------------------------ Area of Application
It means that the greater the area of a pad or plastic shell of an orthosis, the less force will be placed on the skin.
Therefore, any material that creates a force against the skin should be of dimension to minimize the force on the tissue.
The equilibrium principle: The sum of the forces and the bending forces created
must be equal to zero.
This means that three-point pressure or loading system occurs when three forces are applied to a segment in such a way that a single primary force is applied between two additional counter forces with the sum of all three forces equalizing zero.
The primary force is of a magnitude and located at a point where movement is either inhibited or facilitated, depending on the functional design of the orthosis
The lever arm principle: The farther the point of force from the joint the
greater the moment arm and the smaller the magnitude of force required to produce a given torque at the joint.
This why most orthosis are designed with long metal bars or plastic shells that are the length of adjacent segment.
The greater the length of the supporting orthotic structure, the greater the moment or torque that can be placed on the joint or unstable segment.
These three principles act dependently on each other So when designing or evaluating an orthotic devise we
should check that1) There is adequate padding covering the greatest area
possible for comfort.
2) The total forces acting on the involved segment is equal to zero or there is equal pressure throughout the orthosis and no areas of skin irritation.
1) The length of the orthosis is suitable to provide an adequate force to creat the desired effect and to avoid increased transmission of shear forces against the anatomic tissues
General othotic considerations:
The forces at the interface between the orthotic materials and the skin.
The degrees of freedom of each joint. The number of joint segments. The neuromuscular control of a segment, including
strength and muscle tone. The material selected for orthotic fabrication. The activity level of the client. The goal of orthotic fitting is to meet the functional
requirements of the client with minimal restriction.
Functional orthotic considirations1) Alignment: The correction of a deformity or maintenance of a
body segment. e.g. a) Musculoskeletal disorders: Milaukee brace for scoliosis. Dynamic splint to prevent scar shortening in burns. b) Neurological disorders: Tone reducing AFOs in patient with cerebral palsy. CTLSO to prevent motion of cervical region.
1) Movement: a joint may require assistance with motion or resistance to excessive motion: example.
Assistance with joint motion. a) Muscloskeletal disorders: AFO with dorsiflexion assist for dorsiflexor weakness. b) Neurological disorders: RGO assist with spinal cord injury with ambulation.
Resistance with joint motion:
a) Muscloskeletal disorders: Shoe insert for a patient with foot deformity. Finger splints for arthritic hand.b) Neurological disorders: Arm sling for neurological disorders. Swedish knee cage for unstable knee.
3) Weight bearing: to reduce axial loading and reduce the forces placed on a joint.
a) Muscloskeletal disorder Shoe insert with metearsal pad for a diabetic patient with foot
deformity.b) Neurological disorders Heel wedge for a child with cerebral palsy.
4) Protection: protect a segment against further injury or pain.Examplesa) Muscloskeletal disorders: Functional knee brace.b) Neurological disorders; Cock-up splints for post spinal cord injury.
Types of orthosis
Upper limb orthosisTrunk
orthosisLower limb orthosis
Orthoses are named by the joints they encompass
LL orthoses
FO
KO
HO
Foot orthosis
Knee orthosis
Hip orthosis
AFO
KAFO
HKAFO
RGO
Ankle-foot orthosis
Knee-ankle foot orthosis
Hip-Knee-ankle foot orthosis
Reciprocal Gait orthosis
Spinal orthoses
CO
TO
SO
SIO
Cervical orthosis
Thoracic orthosis
Sacral orthosis
Sacroiliac orthosis
AFO
KAFO
HKAFO
RGO
Cervical-Thoracic orthosis
Cervical-Thoracolumbosacral orthosis
Thoracolumbosacral orthosis
Lumbosacral orthosis
UL orthoses
HdO
WO
EO
SO
Hand orthosis
Wrist orthosis
Elbow orthosis
Shoulder orthosis
WHO
EWHO
SEO
SEWHO
Wrist-Hand orthosis
Elbow-Wrist-Hand orthosis
Shoulder-Elbow orthosis
Shoulder-Elbow-Wrist-Hand orthosis
TYPES OF ORTHOSES• LOWER LIMB• Insoles - These are used to help cushion the feet, reduce high
pressure areas or alter the biomechanics of the feet are abnormally shaped so do not fit ordinary footwear.
• Footwear adaptations - Adaptations are made to either compensate for a leg length discrepancy or to alter the angles of the feet when walking.
• Ankle Foot Orthoses - (plastic or conventional metal) These can be supplied to help control or stabilise the ankle and foot. For example, for controlling foot drop or stabilising an osteoarthritic ankle.
• Knee Ankle Foot Orthoses - (plastic or conventional metal) These are used to help control or stabilise the knee, ankle and foot.
• Knee braces - There are various types to help control the knee joint.
• Stockings - These are used to help control swelling, help improve circulation and help prevent ulcers and Deep Vein Thrombosis.
TRUNK
• Corsets and Abdominal Supports - A fabric support to provide some support to the back or stomach.
• Plastic Spinal Supports - Provides firmer support than the corset. They will control movement, as well as support the body to prevent surgery, or after surgery.
• Collars - Varying types to provide different degrees of support and control to the neck.
UPPER LIMB
• Wrist Splints - To support or control movements of the wrist and help reduce pain.
• Some of our supports are stock items but most are custom made devices to suit the individual needs of the patient. This is why you are usually required to have more than one visit to the department.
FOOTWEAR
• These are supplied to those patients who are either diabetic, have a biomechanical need for additional control of the foot and ankle or whose feet no longer fit into conventional footwear.
• Repairs to this footwear are only carried out through the hospital if a war pensioner wears them or if the shoes are have adaptations
