Orthosis & Prothesis 1ST Lecture PDF

ORTHOSIS & PROTH 1ST Lecture Dr Heba Allah Elsayed Lecturer, Sinai University [email protected] sinaiuniversity.net  ORTHOSIS & PROTHESIS Lecture One/Introduction By Dr. Heba Elsayed Lec...

ORTHOSIS & PROTH 1ST Lecture Dr Heba Allah Elsayed Lecturer, Sinai University [email protected] sinaiuniversity.net  ORTHOSIS & PROTHESIS Lecture One/Introduction By Dr. Heba Elsayed Lecturer in Orthopedics  Concentration The ability to think care fully about something you are doing and nothing else QUIZES (3) = 30 marks. MID TERM =20 marks. PRACTICAL =20 marks. FINAL =30 marks. Objectives of the lecture: Understand the terminology and definitions of orthotics.  Determine Four categories of component. Define Orthotic team member roles. Determine types of orthotic design. The properties of materials for selection of orthosis  Materials used in orthosis Evaluation of the patient Prescription guidelines The orthotic terms Orthotics is defined as ‘‘the science and art involved in treating patients by the use of an orthosis.’’ An orthosis is defined as ‘‘an externally applied device used to modify the structural and functional characteristics of the neuromuscular and skeletal systems.’’ An orthotist is defined as ‘‘a person who, having completed an approved course of education and training, is authorized by an appropriate national authority to design, measure and fit orthoses.’’ Definition of orthosis The simplest definition of an orthosis is any externally applied device to an existing body part that improves function, through: 1. Stabilize weak or paralyzed segments or joints 2. Support damaged or diseased segments or joints 3. Limit or augment motion across joints 4. Control abnormal or spastic movements 5. Unload distal segments Advantages of orthotic treatment 1. To relieve pain 2. To manage deformities 3. To prevent an excessive range of joint motion 4. To increase the range of joint motion 5. To compensate for abnormalities of segment length or shape 6. To manage abnormal neuromuscular function (e.g., weakness or hyperactivity) 7. To protect tissues 8. To promote healing 9. To provide other effects (e.g., placebo, warmth, postural feedback) Four categories of orthotic component: 1. Interface components 2. Articulating components 3. Structural components 4. Cosmetic components 1. Interface components are defined as ‘‘those components which are in direct contact with the user and are responsible for transmitting the forces which result in its function and may retain it in place’’ and are considered as including the following: Shells Pads Straps Foot orthoses Shoes (used with an orthosis) Pads Straps Orthotic shoes 2. Articulating components, which are defined as ‘‘components of orthoses used to allow or control the motion of anatomical joints,’’ are to be described by specifying the following:  The anatomical joint whose motions they are intended to allow or control  The permissible motions of the joint when assembled in the finished orthosis  The form of articulation, either motion between parts of the joint or deformation of a part of the joint  The axis of rotation, either monocentric or polycentric. The type of controls that the joint incorporates (e.g., locks, limiting mechanisms, assist/resist mechanisms) 3. Structural components are defined as ‘‘components which connect the interface and articulating components and maintain the alignment of the orthosis’’ and include uprights. 4. Cosmetic components are defined as ‘‘the means of providing shape, colour and texture to orthoses’’ and include fillers, covers, and sleeves. Upright Sleeve The cooperative effort of these two key individuals from the orthotic team, and the sharing of knowledge among the other team members, ultimately will provide the most appropriate prescription for the orthosis and the treatment plan. The orthotic prescription then becomes a part of the road map to achieve the final endpoint of improved patient function. Orthotic team member roles The role of each individual team member can be precisely defined, but overlap occurs in several areas. These areas of overlap should enhance discussion and communication among team members to generate the most appropriate treatment plan. Role of the physician Perform the medical evaluation Explain the diagnosis and prognosis to other team members Alert the team to special considerations, including skin issues, weight-bearing limitations, vascular disease, and spasticity and share knowledge with other team members Assess and manage the patient’s pain control regimen, psychological status Write prescriptions for the orthotic device, Regular monitoring and long-term follow-up Role of the certified orthotist Participate in patient evaluation and generation of the orthotic prescription Act in a consulting role to provide information on device design and materials options Educate the patient regarding the device Fabricate the device to prescription specifications Deliver and check device fit and function Modify and repair the orthosis if, and when, appropriate Follow up with the patient and team members Role of the patient Convey appropriate information to the team members Listen, learn, and follow the team recommendations Comply with the treatment program and proper use of the orthotic device Follow up with the team, particularly if complications or problems related to the orthosis or function occur Identification of Articular or Nonarticular The first element of the classification indicates whether or not an orthosis affects articular structures.  Articular orthoses use three-point pressure systems “to affect a joint or joints by immobilizing, mobilizing, restricting, or transmitting torque.”  Nonarticular orthoses use a two-point pressure force to stabilize or immobilize a body segment. Examples of nonarticular orthoses include those that affect the long bones of the body (e.g., humerus) Three point pressure system F3 Two point pressure system Types of orthotic design: a. Static orthosis b. Serial static orthosis c. Dropout orthosis d. Dynamic orthosis e. Static-progressive orthosis 1. A static or immobilization orthosis can maintain a position to hold anatomical structures at the end of available range of motion, thus exerting a mobilizing effect on a joint. For example, a therapist fabricates an orthosis to position the wrist in maximum tolerated extension to increase extension of a stiff wrist. Because the orthosis positions the shortened wrist flexors at maximum length and holds them there, the tissue remodels in a lengthened form. 2. Serial static orthoses require the remolding of a static orthosis. The serial static orthosis holds the joint or series of joints at the limit of tolerable range, thus promoting tissue remodeling. As the tissue remodels, the joint gains range and the practitioner remolds the orthosis to once again place the joint at end range comfortably. 3. Dropout orthosis allows motion in one direction while blocking motion in another. This type of orthosis may help a person regain lost range of motion while preventing poor posture. For example, an orthosis may be designed to enhance wrist extension while blocking wrist flexion. 4. Elastic tension dynamic (mobilization) orthoses have self- adjusting or elastic components, which may include wire, rubber bands, or springs. An orthosis that applies an elastic tension force to straighten an index finger PIP flexion contracture exemplifies an elastic tension/traction dynamic (mobilization) orthosis. 5. Static progressive orthoses are types of dynamic (mobilization) orthoses. They incorporate the use of inelastic components, such as hook-and-loop tapes, outrigger line, progressive hinges, turnbuckles, and screws. The orthotic design incorporates the use of inelastic components to allow the client to adjust the amount of tension so as to prevent overstressing of tissue. Hook-and-loop tapes Outrigger line Hinges Turnbuckles Screws Metals and plastics are the basic principal materials used in orthotics and prosthetics. To understand recommended design and fabrication procedures, a basic knowledge of the properties of the various available materials is necessary. The properties of materials for selection of orthosis: 1) Density, 2) Resilience, 3) Compressive stiffness, 4) Static coefficient of friction and shear, 5) Durability 6) Compression set. 1. Density Density is a measure of the amount of matter contained within a given space. Light materials have a low density and heavy materials a high density. While a light material may be preferable within insole design to maintain gait efficiency, a low-density material may compress prematurely or ‘bottom out,’ reducing shock attenuation. Conversely, a material of high density will not compress, rendering it unsuitable as a shock attenuator. 2. Resilience Resilience is defined as the amount of energy returned during unloading as a percentage of the amount of energy absorbed during loading. The lower the resilience, the greater the damping of shock attenuation capacity of the material. In the prevention of diabetic foot ulceration, the aim of the orthosis is to minimize energy return. The most appropriate material would be one displaying low resilience and high dampening. 3. Compressive Stiffness The stiffness of a material, defined as the resistance of a material to deformation, is expressed as stress per unit strain and can be measured by applying compressive or tensile stress. A material of low stiffness and rapid deformation may be necessary to ensure the insole is able to mold sufficiently to the contours of the foot and, thus, redistribute pressure away from bony prominences. 4. Coefficient of Friction and Shear Friction is defined as the force between the surfaces of two objects, which act parallel to the surfaces and prevent or resist them sliding or slipping. An increase in the coefficient of friction will result in an increase in the frictional force. Shear is defined as a load composed of two equal opposite parallel forces that tend to displace one part of an object with respect to an adjacent part along a plane parallel to the lines of force. When applied to the prevention of ulceration in diabetic neuropathy, if the coefficient of friction between the sock and the orthosis interface is reduced to below the shear force required to displace and damage the tissue The preferred top cover of the orthotic device for the management of the diabetic neuropathic foot should be designed to minimize shear injury, with a relatively static coefficient of friction. 5. 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. 6. Compression set is the amount of permenant deformation that occurs when a material is compressed to a specific deformation, for a specified time, at a specific temperature. Materials used in orthosis An orthosis can be constructed from metal, plastic, leather, or any combination. Plastic materials, such as thermosetting and thermoplastics, are the materials most commonly used in the orthotic industry. 1. Metals The most widely used metallic elements include iron, copper, lead, zinc, aluminum (or aluminium), tin, nickel, and magnesium. Some of these elements are used extensively in the pure state, but by far the largest amount is used in the form of alloys. An alloy is a combination of elements that exhibits the properties of a metal. The properties of alloys differ appreciably from those of the constituent elements. Improvement of strength, ductility, hardness, wear resistance, and corrosion resistance may be obtained in an alloy by combinations of various elements. Orthotics and prosthetics typically contain alloys of aluminum and carbon steels, particularly stainless steel. 2. Leather Leather is manufactured from the skin and hides of various animals. Today, leather is used for supportive components such as suspension straps, belts, and limb cuffs. Leather is also used to cover metallic structures such as pelvic, thigh, and calf bands. Another important attribute of leather is its moldability. Although numerous techniques are available to mold leather, the most common one in orthotics and prosthetics is to stretch it over a plaster cast after it has been mulled (dampened or soaked) in water. 3. Plastics One of the most important production-related characteristics of an orthotic or prosthetic material is its ability to be molded over a positive model. Plastics are grouped into two categories: a. Thermoplastics. b. Thermosetting materials. a. Thermoplastics Thermoplastic materials are formable when they are heated but become rigid after they have cooled. Thermoplastics are classified as either low- temperature or high-temperature materials, depending on the temperature range at which they become malleable. Low-temperature thermoplastics become moldable at temperatures less than 80°C and can often be molded directly on the patient’s limb, whereas high-temperature materials require heating to much higher temperatures and must be molded over a positive model of the patient’s limb. One advantage of thermoplastic materials is that they can be reheated and shaped multiple times, making possible minor adjustments of an orthosis or prosthesis during fittings. Thermoplastics are the material of choice for “shell” designs in which structural strength is required. Certain low-temperature thermoplastics, those moldable at temperatures less than 80°C, can be applied and shaped directly to the body. Some of the most commonly available materials include Kydex, and Polysar. These materials are most often reserved for orthotic devices that are designed to provide temporary support and protection. Their susceptibility to repetitive stress, high loads, and temperature changes usually limits their use to spinal and upper extremity orthoses. High-temperature plastics frequently used in the production of orthotics and prosthetics. The most commonly are used materials include polyethylene, polypropylene. b. Thermosetting Materials Thermosets are plastics that are applied over a positive model in liquid form and then chemically “cured” to solidify and maintain a desired shape. Although this group of plastics has inherent structural stability, their shape can only be changed by grinding. Thermosetting plastics cannot be reheated without destroying their physical properties. Some of the most common thermoset resins used to produce rigid orthoses are acrylic, polyester, and epoxy. Because acrylic resins are strong, lightweight, and somewhat pliable. 4. Composites Composites are the combination of two or more materials with distinctly different physical or chemical properties that together produce a material with enhanced performance characteristics relative to their material properties as a single substance. Evaluation of the patient A clear understanding of the patient’s disease process. The impact of the disease on the patient’s current functional status and the patient’s expectations or functional goals Comorbid conditions; diabetes, neurologic disease, vascular disease, visual impairment. Physical examination of the patient should include assessment of strength, range of motion, sensation, tone, skin integrity, and presence of edema. Physical examination include all of these components in the involved limb but also in uninvolved limbs. An overall description of the patient’s body size and habitus, including specific body weight. Functional tasks such as transfers, ambulation, and self-care tasks. Cognitive status should be assessed Prescription guidelines The patient’s name, date of birth, and other identifying information The medical information should be specific and directly related to the functional deficit or reason for the orthosis. The resulting disability and the prognosis related to the disease should be included. The name of the orthotic practitioner or orthotic company Details of the orthosis, starting with the each segment or component of the orthosis Materials specification, such as thermoplastics, metals, or carbon fiber, Any corrective straps, flanges, or wedges should be included Prescription guidelines