Introduction to Orthotics and Prosthetics

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Introduction to Orthotics and Prosthetics


Leslie K. King



LEARNING OBJECTIVES



1. Define the terms orthotics and prosthetics.


2. Obtain basic understanding of materials.


3. Learn the nomenclature—the naming of orthoses and prostheses in relation to the joint they support or replace.


4. Describe the key differences when off-the-shelf orthoses can be chosen instead of custom fabricated.


5. Have a general understanding of orthotic options for supporting major joints in the body.


6. List levels of amputation sites as well as the reasons for amputation.


7. Develop an understanding of basic prosthetic componentry and how the selection of componentry relates to patient function and outcome.



KEY TERMS



When it comes to selecting an appropriate orthosis or prosthesis for a patient there are numerous options available for either prefabricated or custom fabricated devices. The plethora of possible manufacturers makes it increasingly difficult to select the best device simply because of the number of optimal choices. The proper selection of each device, then, is based upon diagnosis, functional goals, and the patient’s cognitive and physical abilities to properly don and doff these devices.


The process developed for naming orthoses and prostheses is a fairly simple technique. The International Standards Organization (ISO) recognizes common descriptors for orthoses and prostheses, based on the acronyms from the body joint or joints that are supported or replaced (Table 26-1). This method of nomenclature is both effective and easily learned.




ORTHOTICS


An orthosis is a product or device that supports a body part or joint. These devices provide the patient with stability, support, positioning, and protection. Orthoses range from a prefabricated wrist splint to a custom fabricated reciprocating gait orthosis. Orthoses are tools used to help the patient become more independent and functional with tasks such as activities of daily living (ADLs) and ambulation. Selecting the proper device is crucial in providing the patient with optimal support, results, care, and outcome results.


There are two key terms commonly used when discussing orthotics: splinting and bracing. Splinting is a term used today and most often refers to an orthosis that will immobilize a joint, such as a finger splint used to hold a broken phalange immobile or a hip spica splint fitted to a patient postsurgical hip repair or replacement, and that will allow only a specific range of motion as rehabilitation protocol requires. Bracing is a term that is still used today by the lay population; it is a dated term for clinicians. The term orthotic is derived from the Greek ortho, meaning to straighten. Today, when speaking of orthotics, it relates to the biomechanical, musculoskeletal support, and correction of abnormalities within the human body.



PROSTHETICS


A prosthesis is any device that replaces a body part. This group consists of arms, legs, partial feet, hands, ears, breasts, and so on. The goal for each prosthesis is to provide function, body balance, ease of use, and optimal cosmesis in order to restore self image, quality of life, and independence (Table 26-2). Prostheses are custom fabricated and require adjustments and realignment on a regular basis.



The amount of componentry, or parts of a prosthesis, is dependent upon the involved level of amputation. For an upper extremity prosthesis, the components may include a socket, shoulder joint, pylon, elbow joint, wrist unit, and a hand, depending upon where the amputation site is located along the arm. For a lower extremity prosthesis, the components are similar to upper extremity, but the hands and wrists are replaced by feet, knees, and hip joints. Each of the components (for both upper- and lower-extremity prostheses) play a specific role in whether the prosthesis is ultimately used successfully by the patient. The socket, for example, is the custom fabricated portion created from a mold of the patient’s residual limb. This mold is obtained by casting the patient or by computer-aided manufacturing (CAM), a process during which the residual limb is scanned using a computer-aided design (CAD) program. Proper fit of the socket is crucial, and intimacy of the fit is directly related to the patient’s end result for use and wear time. The rest of the prosthetic componentry is carefully selected from the vast list of products available from manufacturers. Hands, elbows, and shoulder joints are chosen by the prosthetist in order to assemble the most appropriate and functional prosthesis.


All prostheses use prosthetic socks for optimal fit. Prosthetic socks are available in different thicknesses referred to as ply. As the amputee retains or loses fluid throughout the course of the day, adding or removing a sock is done in order to maintain the optimal fit of the socket. This process is referred to as sock management. Prostheses may also incorporate silicone liners for suspension and cushion. Liners are fabricated out of materials such as silicone, polyurethane, and gel elastomers. These materials are chosen because of their ease of use for donning or doffing, quality of hygiene, and durability. To obtain proper limb length, a pylon, which is an aluminum or stainless steel tube, is fitted between the foot and the socket or knee unit.



Fitting for Orthoses or Prostheses


As each orthosis or prosthesis is being fabricated or fitted, the functional goals of each patient are key to making the most appropriate selection for componentry. The patient’s weight, age, activity level, and potential to regain independence and agility are the factors used to determine which type of orthosis or type of material to choose.


When selecting orthotic or prosthetic components it is important to consider what devices may be necessary for safety and transferring from one seated position to another. This particular use offers the patient something to support the lower extremity or provide a prosthetic leg on which to stand, or use for weight bearing to assist themselves or care givers.



Material Selection


When fabricating orthoses and prostheses, the material selection is the first consideration of the process. There are multiple types of thermoplastics, metals, carbon fiber composites, and interface materials to choose from. Each type of material will have certain desirable characteristics or properties that will best suit each patient’s needs. Body weight, activity level, amount of rigidity needed, flexibility of material, energy storing properties, amount of cushioning required, and patient strength are all variables to consider when selecting fabrication materials (Table 26-3).






Carbon Fiber Composites


Carbon fiber composites are being used more commonly in custom and prefabricated orthoses. Floor reaction, anterior tibial shell AFOs, foot plates, knee bracing, and KAFOs all use varying layers and pattern designs of carbon composites. The patterns create varying degrees of strength, flexibility, weight, and energy storing properties. This advancement has been beneficial to all users: the ability to provide a support that is lightweight and conserves energy. Reduced energy output for ambulation during the day is a tangible benefit. The potential of wearing a less cumbersome device under clothing is a cosmetic advantage, and also provides a more optimal, intimate fit of the device. Lastly, the energy storing property provides each patient with the ability to work and walk for longer periods of time, thus resulting in a more productive and happier individual. This same technology of layering carbon fiber in multiple, pattern specific directions is utilized in the production of prostheses feet in order to produce the same lightweight, yet strong, energy return benefit.




DEVICE SELECTION


According to information gathered from the patient and the prescription ordered by the physician, a decision must be made by the physical therapist (PT) to determine whether to fit the patient with a prefabricated orthosis or a custom fabricated device. A prefabricated orthosis is designed with a high percentage of the general population’s size and measurements taken into account. The first choice is to fit the patient with a prefabricated orthosis as long as the patient’s measurements fit into the measurement guidelines provided by the manufacturer, and proper fit and function are not compromised. The prefabricated orthosis can be an appropriate and cost-saving selection. When the patient’s size and/or skeletal deformities will not allow for proper fit of a prefabricated orthosis, then the patient will be casted, scanned, and measured as needed to custom fabricate the orthotic device. Custom fabricated orthoses include wrist splints, knee orthoses, and diabetic shoes.


The advancements made in prefabricated orthoses have created a wide range of readily available prefabricated products. Therefore a large percentage of the general population can be fitted with these new devices. However, there are adjustments and changes necessary for a custom fit and optimal patient benefit. There are certain indications, diseases, and deformities that require custom fabricated splints, including progressive, dynamic, and static varieties. A progressive splint is one that can be modified as the patient’s rehabilitation progresses so that it will accommodate those changes and still provide the necessary support from a greater to lesser support and allow for increases in range of motion (ROM). Dynamic splinting uses springs or tension rod joints to apply a constant resistance or assistance for flexion or extension. The amount of tension is adjustable and can be set to meet rehabilitation protocols. Lastly, static splinting holds the joint or joints in a specific position.


All prosthetic devices are fabricated by combining a custom made socket designed from a mold or scanned file taken of the residual limb and selected componentry for the rest of the prosthesis that will be replacing the amputated body part. Depending upon patient size, measurements, and deformity, items such as liners can be custom fabricated if a prefabricated item does not fit properly. Patients who exceed the recommended weight limit for prefabricated prosthetic feet and knee units can also be fitted with a custom fabricated component.



Orthoses


Upper Extremity



Fingers, hand, and wrist

A splint for the fingers and hand should only support the affected joint or joints and allow the unaffected joints free ROM. There are single joint splints for the fingers available, such as proximal interphalangeal (PIP) and distal interphalangeal (DIP) splints which maintain or promote active range of motion (AROM) in the phalanges after sprains, fractures, or contractures. Some splints maintain or hold the joint in a fixed position, whereas dynamic splints that are spring-loaded allow the patient some movement of flexion or extension while applying constant force in the desired direction (Fig. 26-1). One particular type of wrist-hand-finger orthosis (WHFO) is the Thomas suspension splint. The function of this splint is to apply tension to the wrist joint and thumb in order to dorsiflex the wrist for diagnoses such as radial palsy. The long opponens splint is often used for flexion contractures, nerve or tendon damage due to traumatic accidents, or rheumatoid arthritis. These splints offer dynamic finger extension and allow the patient to use flexors needed for gripping.


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Fig. 26-1 Static immobilization splint. This static splint immobilizes the thumb, fingers, and wrist. (From Coppard BM, Lohman H: Introduction to splinting: a clinical reasoning and problem-solving approach, ed 3, St Louis, 2008, Mosby.)

Another example of a functional custom fabricated WHFO is the tenodesis splint (also known as a wrist action splint) (Fig. 26-2). This splint is used to increase functional levels and independence mainly for quadriplegia. The design is ultra lightweight and uses the available ability to flex the wrist to accentuate the natural movement of opposition for gripping objects by using the three-jaw chuck pinch position. The wrist-driven wrist/hand orthosis employs the flexor hinge principle. The fingers and thumb are stabilized in the position of function. A small amount of wrist extensor strength will create flexion motion in the metacarpal phalangeal (MP) joints to produce adequate pinch for a variety of daily activities. Because it is custom fabricated, this style of splint requires a cast of the hand and forearm and measurements for fabrication.


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Fig. 26-2 A tenodesis splint uses active wrist extension to aid passive finger flexion. (From Coppard BM, Lohman H: Introduction to splinting: a clinical reasoning and problem-solving approach, ed 3, St Louis, 2008, Mosby.

There are multiple orthotic options available when supporting the hand and wrist, depending on the diagnosis and desired limitations for movement. For diagnoses such as carpal tunnel syndrome, tendonitis, or a sprain, a cock-up wrist splint, which holds the wrist in a neutral position is the most common choice (Fig. 26-3, A). This splint is a prefabricated brace that is readily available in varying sizes. For diagnoses such as a contracture secondary to a cerebral vascular accident (CVA) or rheumatoid arthritis (RA), a prefabricated malleable wrist-hand-finger orthosis will suffice. This orthosis is progressive in design because the wrist joint and finger platform is easily flexed or extended to accommodate gains made by stretching protocols in physical therapy sessions. These prefabricated, lightweight splints are called platform or resting splints and provide static positioning (Fig. 26-3, B). Some of the soft versions of these splints are more skin-friendly because they offer the option of a cover that can be removed and washed, which promotes good hygiene.


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Fig. 26-3 A, Completed radial bar cock-up splint. B, Positional resting splint. (A, From Early MB: Physical dysfunction practice skills for the occupational therapy assistant, ed 2. St Louis, 2007, Mosby. B, From Pierson FM, Fairchild S: Principles & techniques of patient care, ed 4, St Louis, 2008, Saunders.)


Elbow

Fitting choices for elbow orthoses can usually be prefabricated. A lateral epicondylitis splint (a band with a silicone or air pocket), is used to disperse the pressure placed on the tendon caused by use over a greater area, thus decreasing the point of high stress and pain (Fig. 26-4). ROM splints that limit AROM or provide pressure to increase ROM can also be purchased as prefabricated orthoses. The Flex POP Elbow Orthosis by RCAI (St. Petersburg, Fla.), for example, provides rehabilitation for joint stiffness and contractures, instabilities, strains, sprains, and ligament repairs. This ROM elbow orthosis offers flexion/extension stop sets at 5-degree increments, which allows changes to be made in therapy sessions as the patient progresses. Dynamic elbow splints can be used when the function desired is to gain ROM by applying a constant stretch to the elbow joint tendons and muscles. Protocols are set for wear time and when the tension placed upon the joint can be increased. Static splints can be set to a designated degree of flexion or extension and depending upon the style or brand, may or may not be adjustable. The physician’s prescription, rehabilitation protocols, and the patient’s level of compliance and tolerance all contribute to the decision-making process when fitting these types of elbow splints. Elbow contractures can be caused by a variety of injuries or diseases, such as cerebral palsy and CVA.


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Fig. 26-4 Tennis elbow strap applied. (From Pierson FM, Fairchild S: Principles & techniques of patient care, ed 4, St Louis, 2008, Saunders.)



Specialized orthoses for the upper extremity

ADLs require a multitude of orthoses to promote independence for individuals who have suffered a stroke or debilitating injury. There are hand and wrist splints that are used to assist with feeding oneself, holding an ink pen, using a brush, and so on (Fig. 26-6). There are many types of foam available to place around utensils and items with handles to increase their circumference, therefore decreasing the grip strength and ROM needed to hold and use such items.


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Fig. 26-6 Eating using a special splint with a utensil holder fitted to the hand. (From Early MB: Physical dysfunction practice skills for the occupational therapy assistant, ed 2, St Louis, 2007, Mosby.)

Fracture splinting uses a compression method for stabilization of the fracture site. The compression of fluid and soft tissue around the fracture site is key when providing a femoral, humeral, radial, or ulnar splint. These splints can be modified to a custom fit by heating and/or adding a soft interface material to provide added comfort. The fracture splint is a bivalve, two-piece orthosis and uses adjustable hook and loop strapping (Fig. 26-7). The splint will allow movement of the unaffected joints such as elbow and wrist for the ulnar fracture. The technique and principles used in splinting for upper extremity fractures is the same for lower extremity fractures.


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Fig. 26-7 Designed to facilitate adjustments as edema diminishes, this two-piece metacarpal fracture splint has excellent contiguous fit. (Courtesy Lin Beribak, OTR/L, CHT, Chicago, Ill. In Fess EE, Gettle K, Philips C, et al: Hand and upper extremity splinting: principles and methods, ed 3, St Louis, 2005, Mosby.)


Spine and Trunk



Cervical spine

Cervical orthoses are fitted for the purpose of supporting the cervical muscles; limiting rotation, flexion, and extension; or immobilization of the cervical spine. A soft cervical collar can be fitted for lesser injuries such as sprains and strains. The soft collar is a prefabricated orthosis made of foam with a cotton cover and has a hook and loop closure in the back (Fig. 26-8). They are available in different heights and lengths. A cervicothoracic orthosis is a semirigid, two-piece brace that can be fitted for whiplash, degenerative joint disease, arthritis, and presurgical or postsurgical repairs. These collars are adjustable in height, circumference, and rigidity, but, as with all bracing, the therapist must always check pressure points to make sure that there is no skin breakdown.


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Fig. 26-8 The Philadelphia collar, with an anterior opening for tracheostomy care. (From Shurr DG: Prosthetics, orthotics and orthopaedic rehabilitation. In Clark CR, Bonfiglio M, editors: Orthopaedics: essentials of diagnosis and treatment, New York, 1994, Churchill Livingstone.)


Lumbosacral spine

When supporting the spine, there are numerous custom and off-the-shelf products available. The severity of the injury, pain, or disease determines the amount of support that should be fitting to each individual. The more that an individual wears the support, the more dependant he or she becomes upon the support because the abdominal muscles are now not required to work as when unsupported. With this concept in mind, the least amount of support necessary is always the best option.


Trunk support encompasses abdominal binders, rigid panel supports, hyperextension braces, and custom fabricated scoliosis orthoses. Each orthosis will require certain specific circumferential measurements, length measurements, width measurements, and for custom bracing, casting of the torso. When making a custom spinal orthosis, material selection becomes very important. Selecting the necessary amount of rigidity with the least amount of weight is crucial.


The most flexible and therefore the least rigid lumbosacral orthosis (LSO) is the abdominal binder. This orthosis is a stretchy surgical elastic binder that is available in varying widths and lengths to provide optimal fit to a wide range of sizes. The LSO provides support and compression to the abdominal muscles, which in turn support the lower back. The abdominal binder is most often fitted for low back pain.


Pregnancy supports are abdominal binders and are available for use during pregnancy. They provide relief to the lumbar spine as well as support and assistance with unloading the abdomen while compressing the hip complex.

Related posts:

Cartilage Healing Gait Patient Supervision and Observation During Treatment Orthopedic Management of the Elbow Flexibility and Stretching Orthopedic Management of the Hip and Pelvis

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Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on Introduction to Orthotics and Prosthetics

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