Thermoplastic Splinting Materials
Most commonly used to fabricate splints; considered low temperature because they soften in water heated between 135 - 180 degrees F; therapist can usually place against skin while plastic is still moldable
Thermoplastic Splinting Materials: Elastic
*Have some amount of memory
*Coating to prevent the material from adhering to itself
*Longer working time
Thermoplastic Splinting Materials: Plastic
*Drapable & have low resistance to stretch
*Often used; highly conforming
*Require skill in handling
Thermoplastic Splinting Materials: Rubbery/Rubberlike
*More resistant to stretching and fingerprinting
*Less conforming
Handling Characteristics: Memory
*Describes a materials ability to return to its preheated shape, size, and thickness when reheated
*100% of this will return to their original size & thickness when reheated
*Most with high this turn translucent during heating; can be used as indicator of proper heating
*Allows therapists to reheat & reshape splints several times; must be constantly molded to sustain maximal conformability
*Good for novices
*May pose problems with fine adjustments
Handling Characteristics
Thermoplastic materials properties when heated and softened
*Memory
*Drapability
*Elasticity
*Bonding
*Self-Finishing Edges
Performance Characteristics
Thermoplastic materials properties after the material has cooled & hardened
*Conformability
*Flexibility
*Durability
*Rigidity
*Perforations
*Finish
*Colors
*Thickness
Handling Characteristics: Drapability
*The degree of ease with which a material conforms to the underlying shape without manual assistance
*Duration of heating is important
*The longer the material heats, the softer it becomes & the more vulnerable it becomes to gravity & stretch
*Must be handled with care after heating
*Best positioned on a clean countertop during cutting
*Difficult to use for large splints & most successful on cooperative person who can place body part in gravity assisted position
*May pose problems for novices
Handling Characteristics: Elasticity
*Materials resistance to stretch
*Tendency to return to its original shape after stretch
*Can be worked aggressively
*Helpful when working with uncooperative persons, those with high tone, or when one splint includes multiple areas (forearm/wrist)
**Materials with little elasticity will stretch easily and become thin; therefore, light touch must be used
Handling Characteristics: Bonding
*The degree to which material will stick to itself when properly heated
*Some are coated, others are not
*Those with coating always require surface prep with a bonding agent or solvent
*Self-bonding (uncoated) may not require surface prep, but some thermoplastic materials have a coating that must be removed for bonding to occur
*Coated materials tack at the edges because the coating covers only the surface and not the edges
*All thermoplastics whether coated or uncoated, forms stronger bonds if surfaces are prepared with a solvent or bonding agent (which removes the coating from the material)
Handling Characteristics: Self-Finishing Edges
Allows any cut edge to seal and leave a smooth rounded surface if the material is cut when warm; saves time because don't have to manually roll or smooth edges
Handling Characteristics: Other Considerations
*Heating time: should be monitored closely; prevents material from getting excessively soft & stretchy; should be cognizant of temp material holds before applying to skin
*Working time: material that is 1/8 thick is usually pliable for 3-5m; some will allow for 4-6m; materials that are thinner than 1/8 or perforated cool more quickly
*Shrinkage: especially important consideration with circumferential design; precautions to prevent difficulty removing a thumb or finger from a circumferential component of a splint
Performance Characteristics: Conformability
*The ability of thermoplastic material to fit intimately into contoured areas
*Splints that are intimately conformed are more comfortable because they distribute pressure & reduce the likelihood of the splint migrating
Performance Characteristics: Flexibility
*Can take stresses repeatedly
*Important for circumferential splints because they must be pulled open for application & removal
Performance Characteristics: Durability
*The length of time splint material will last; rubberbased materials are more likely to become brittle with age
Performance Characteristics: Rigidity
*Strong & resistant to repeated stress
*Especially important with medium > large splints (elbows/forearms); require rigid material to support more weight
*In smaller splints, rigidity is important if splint must stabilize a joint
*Can be enhanced by contouring
Performance Characteristics: Perforations
*Will allow for air exchange to underlying skin
*Designed to reduce weight
*Precautions: should not be stretched because stretching will enlarge the holes & decrease strength/pressure distribution; cut between perforations to prevent uneven or sharp edges
Performance Characteristics: Colors
*May affect acceptance & satisfaction
*Darker colors soil less
*May be used to help a person with neglect attend to one side of body
*Easily seen; helps prevent loss
Performance Characteristics: Thickness
*Common is 1/8 inch
*Some available in 1/16, 3/32, 3/16
*Thinner are commonly used for arthritic patients and pediatrics
*3/16 commonly used for LE splints and fx braces
*Plastics thinner than 1/8 will soften and harden more quickly
*Novices may find it easier to splint with 1/8 inch than thinner
Ezeform
Rigidity
Conformability/Drapability
Moderate Drapability
Resistance to Stretch
Self-Adherence
Splinting: Patterns
*A good pattern is necessary for success
*Should be made individually
*If person's hand cannot be flattened for pattern; contralateral hand should be used
*If contralateral hand cannot be used, the therapist may hold the paper in a manner so as to contour to the hand position
Splinting: Fitting the Pattern
*Moistening the paper & applying to the person's hand helps the therapist determine which adjustments are required
*Patterns from aluminum foil work well to contour the pattern to the extremity
*Sometimes it is easier to make new pattern if too many adjustments are necessary
Splinting: Tracing, Heating, & Cutting
*Use an awl to scratch pattern
*Heating temps 135-180 degrees F
*If heating in hydrocollator, problems may occur with vertical stretch from gravity
*Cut with round or flat edges scissors
Splinting: Positioning Client
*Should be comfortable, especially for the shoulder & elbow
*May use gravity assisted position for hand splinting by having the person rest the dorsal wrist area on a towel roll while the forearm is in supination to maintain proper wrist positioning
*May ask the person to rest the elbow on a table and splint the hand while it is in a vertical position
*For those with stiffness, modalities may be used prior to splinting
Splinting: Molding
*Rinse off
*Check temperature
*For those with sensitive skin, stockinette prior to application of splinting material
*To speed up cooling process, therapist may use cold spray or cold water
Splinting: Adjustments
*Amount of adjustments possible depends upon the property of the material & cooling time that has elapsed
*Heat gun may be used
Splinting: Strapping
*Rounded corners decrease the chances of corners peeling off
*Strap placement is critical to a proper fit
*Wrist strap placement should be at the wrist, not proximal to the wrist
Splinting: Padding & Pressure
*Can adjust with heat gun
*Padding should not be added as an afterthought
*Space must be allowed for padding
Prefabricated Splints: Advantages
*May save time & effort (if the splint fits well)
*Immediate feedback from client in terms of satisfaction & therapeutic fit
*Variety of material choices
*Some clients prefer sports-brace appearance
Prefabricated Splints: Disadvantages
*Unique fit is often compromised
*Little control over therapeutic positioning of joints
*Expensive to stock a variety of sizes & designs
*Prefabricated and soft splints usually made for a few target populations (cannot address all conditions requiring unique or creative splint design)
Splinting: Selecting A Splint
*Diagnosis
*Age
*Medical Complications
*Goals
*Splint Design
*Occupational Performance
*Person's or Caregiver's Ability to Comply with Instructions
*Independence with Splint Regimen
*Comfort
*Environment
Arches of the Hand
To have a strong functional grasp, the hand uses the following three arches:
1. Longitudinal
2. Distal transverse
3. Proximal transverse
Proximal Transverse Arch
*Fixed & consists of the distal row of carpal bones
*Rigid & acts as a stable pivot point for the wrist & long-finger flexor muscles
*Transverse carpal ligament & the bones of the proximal transverse arch form the carpal tunnel
Distal Transverse Arch
*Deepens with flexion of the fingers
*Mobile & passes thru the metacarpal heads
Longitudinal Arch
*Allows DIP, PIP, & MCP joints to flex
*Follows the longitudinal axes of each finger
*Because of the mobility of their base, the 1st, 4th, & 5th metacarpals move in relationship to the shape & size of an object placed in the palm
*Grasp is the result of holding an object against the rigid portion of the hand provided by the second & third digits
Distal Palmar Crease
*Extends transversely to a point midway between the third & second MCP joints
*Landmark for the distal edge of the palmar portion of a splint intended to immobilize the wrist while allowing motion of the MCP's
Thenar Crease
*Begins at the proximal palmar crease & curves around the base of the thenar eminence
*Should define the limit of the splint's edge; if the splint extends beyond the thenar crease toward the thumb, thumb opposition & palmar abduction of the CMC joint is inhibited
Distal Wrist Crease
*Extends from the pisiform bone to the tubercle of the trapezium
*Forms a line that separates the proximal and distal rows of the carpal bones
*Assists in locating the axis of the wrist motion
*Volar surface
Proximal Wrist Crease
*Corresponds to the radiocarpal joint and delineates the proximal border of the carpal bones, which articulates with the distal radius
*Assists in locating the axis of wrist motion
*Volar surface
Digital Palmar Flexion Creases
*Digits II thru V
*Distal digital = DIP; marks the DIP joint axis
*Middle digital = PIP; marks the PIP joint axis
*Proximal digital = MCP; is distal to the MCP joint axis at the base of the proximal phalanx
*** Creases are close to, but not always directly over bony joints