Immobilization is indicated not only for fractures, but also for dislocated joints that have been reduced. When a joint becomes dislocated, the ligaments that had provided its stability are disrupted, and the joint is susceptible to redislocation until healing has occurred.
The materials most commonly used for orthopedic immobilization are plaster of Paris (calcium sulfate) and fiberglass fabric combined with a polyurethane resin. Fiberglass has the advantages of being lightweight, fast setting, and resistant to damage by moisture. However, it is not as malleable as plaster, so it might not conform as well to the contour of the limb. This may be an issue when the purpose of the dressing is not only to provide immobilization but also to maintain the position of the fragments once a displaced fracture has been reduced.
Whether plaster or fiberglass is used for immobilization depends on a number of factors, including the emergency physician's preference, the philosophy of the orthopedic community, the needs of the patient, and the hospital's resources.
The chemical reactions that cause plaster or fiberglass to set are initiated by contact with water. The higher the water temperature, the faster the materials harden. However, these reactions are exothermic, meaning they liberate heat. The faster the setting process, the more heat is generated. Therefore, the temperature to which the skin ultimately is exposed will be the additive result of the water temperature and the heat released by the chemical reaction. For this reason, severe burns may occur when plaster or fiberglass has been immersed in mildly hot water, even though the temperature of the water itself would not be sufficient to cause such burns. Although there is no universally prescribed ideal water temperature, a safe practice is to make the water room temperature. If steam is visible, the water is certainly too hot.
To avoid irritation and to minimize the potential for pressure sores, plaster or fiberglass dressings should include several layers of padding over the skin. When non-prepadded longitudinal plaster splints are used, cast padding has to be applied separately. The padding does not necessarily have to be circumferential. Several layers of longitudinal padding will effectively protect the skin as long as they exceed the width and length of the splinting material. The best way to ensure this is to fashion the dry splint first, then measure the padding over it. Longitudinal splints may be fashioned from fixed-length plaster strips, from plaster rolls normally used to create circumferential casts, or from prepadded material with plaster or fiberglass enclosed. The splint should be long enough to provide the leverage needed to immobilize the injured joint. To immobilize the elbow, for example, a splint should begin distal to the wrist and extend high up the lateral arm, almost to the level of the humeral neck. To immobilize the ankle effectively, a splint should extend from beneath the metatarsal heads to the proximal calf. If the fracture is along the midportion of a distal extremity (i.e., the forearm or the lower leg) rather than at a joint, the splint should be long enough to immobilize the joint above and the joint below the fracture.
When a splint is fashioned from plaster rolls, determine the length of the splint by measuring out a single layer along the extremity according to the principles described previously. Then, on a flat surface, unroll the plaster back and forth over itself to make a multilayered splint. If fixed-length plaster strips are used instead of rolls, the only way their length can be customized is to shorten them, so an adequate length should be selected at the outset and trimmed as necessary. In either case, the splint should be at least 12 layers thick for an adult. Even more layers should be used for children, who typically remain as active as possible and have little regard for protecting the dressing.
When the dry splint has been prepared, measure out several layers of padding over it, making the padding longer and wider than the plaster. After setting the padding aside, grip each end of the splint and immerse it in water, keeping it submerged until bubbling stops (indicating that water has been fully absorbed into the interstices of the material). Then withdraw the splint and remove the excess water by sliding the compressed thumb and index finger along the length of the plaster on each edge. (Use a stripping motion, rather than crumpling or wringing out the dressing, or much of the plaster may be lost.)
The next step, frequently overlooked, is to lay the splint on a flat surface and massage the layers into one another so that they fuse together. This creates a strong dressing that is solid on cross-section. A splint whose separate layers are still visible on cross-section is much weaker.
The padding should now be laid on the plaster and the dressing applied to the extremity, with the padded surface against the skin. When two plaster segments are used, as for a thumb spica or a posterior ankle mold with an additional transverse "sugar tong" component, no padding should be interposed between the segments. Rather, they should be molded into each other where they overlap. An assistant can hold the splint against the extremity while it is wrapped in place with gauze bandage. The assistant should use the palms, rather than the fingertips, when holding the splint in place. Hardened finger dents may cause irritation or even pressure sores. When a compressive effect is desired, an elastic bandage may be wrapped over the gauze. (If an elastic bandage is wrapped directly onto plaster without an interposed layer of gauze, it will set into the plaster and may lose most of its compressive function.)
While the plaster is setting, the affected joint may need to be held in a particular position. Again, use the palms, rather than the fingers, for reasons already described. Once the setting process is well under way, the position of a joint should not be changed, or the dressing may crack and become functionally useless. If the joint has gradually migrated from the desired position, the clinician must decide to accept the current position or remove the dressing and start over. There is no need to feel hesitant about the latter course. Patients generally appreciate a desire for perfection by their clinician.
Some plaster or fiberglass splinting products are manufactured with the immobilization material already enclosed in padding, either as strips of predetermined length or as rolls from which splints may be cut to the desired length. Precut strips come packaged in air-tight foil. When a roll is used, the cut end is sealed with a tight clip to protect the exposed material. (Even when not immersed in water, fiberglass may set within 10 to 15 minutes, simply from exposure to moisture in the air.)
Prepadded material is fast and convenient to use because the layers are already in place and the padding need not be applied separately. However, the potential disadvantages are that the thickness of the dressing cannot be customized, and the material does not lend itself to applying two overlapping segments, because they cannot be molded into each other to create a sturdy dressing. If these issues are not a consideration, then prepadded material is a reasonable choice.
TYPES OF IMMOBILIZATION DRESSINGS
The more common immobilization dressings used in the ED are discussed next and are summarized in Table 267-3.
TABLE 267-3Immobilization Devices and Uses ||Download (.pdf) TABLE 267-3 Immobilization Devices and Uses
|Immobilization Technique ||Clinical Application |
|Shoulder immobilizer || |
Shoulder dislocation (postreduction)
Humeral neck fracture
|Sling ||A variety of upper-extremity injuries, in conjunction with other immobilization techniques; may be used alone for nondisplaced or clinically suspected fracture of the radial head. |
|Long-arm gutter || |
Elbow fracture other than nondisplaced radial head fracture
Reduced elbow dislocation
|Sugar-tong ||Wrist or forearm fracture |
|Short-arm gutter ||Metacarpal or proximal phalanx fracture. (Ulnar gutter for fourth or fifth ray; radial gutter for second [index] or third [middle] ray.) |
|Thumb spica || |
Scaphoid fracture (proven or suspected)
Thumb metacarpal or proximal thumb phalanx fracture
|Knee immobilizer || |
Fracture or reduced subluxation of patella
Knee dislocation, postreduction (temporary)
Tibial plateau fracture
Knee ligament injury
Suspected meniscal tear (provided the knee can be fully extended)
|Posterior ankle mold (consider above-the-knee extension and/or adjunctive use of ankle sugar-tong for unstable ankle injuries) || |
Ankle dislocation or fracture-dislocation
Unstable ankle fracture (high distal fibular fracture or medial and/or posterior malleolar fracture)
Widened medial mortise (indicates disruption of stabilizing medial structures)
Metatarsal fracture (alternative immobilization dressings may be used)
|Ankle stirrup || |
Simple ankle sprain
Stable lateral malleolus fracture (below the superior border of the talus) without other ankle involvement (no medial swelling or tenderness, posterior malleolus intact)
|Hard-soled shoe || |
Some metatarsal fractures (see the section Hard-Soled Shoe later in this chapter)
|Short-leg walking boot ||Some toe or foot contusions or fractures where weightbearing is allowed19 |
This is a removable Velcro®-fastened device that keeps the arm in "sling position" but allows less mobility than a sling (Figure 267-8). A wide band wraps around the thorax. Two cuffs are attached to the thoracic piece: one on the lateral side, which grasps the upper arm, keeping the shoulder adducted; and one anteriorly, which holds the wrist to the chest, keeping the shoulder internally rotated. This dressing is suiTable for fractures about the shoulder girdle, including clavicle and well-positioned humeral neck fractures, and for reduced shoulder dislocations.
A shoulder immobilizer is also commonly used for acromioclavicular separations, although from a mechanical standpoint, the ideal dressing for this injury is one that exerts upward pressure on the elbow and downward pressure on the clavicle to bring the clavicle and acromion back into alignment. Commercial versions of such dressings exist, but they are cumbersome to apply and uncomforTable to wear, leading to noncompliance. A shoulder immobilizer (or sling and swathe) is an accepTable alternative dressing.
Although it does not provide rigid immobilization, a sling (Figure 267-9) may be used as an adjunct to other splinting techniques for a variety of upper extremity injuries to enhance comfort, reduce motion, and provide some degree of support and elevation to the upper extremity. In some cases, as for nondisplaced fracture of the radial head, it may be used alone, without the need for supplementary immobilization.
Clavicle Strap (Figure-of-Eight Bandage)
The figure-of-eight clavicle strap is mentioned only as a historical note. This dressing had long been considered the appropriate immobilization method for fracture of the clavicle, but in fact it is fairly ineffective at maintaining alignment of the fracture fragments and produces no difference in clinical outcome compared with a simple sling.20 In addition, the clavicle strap may be awkward to apply, may require frequent readjustment, may cause problems related to pressure on the brachial plexus, and is often uncomforTable for the patient. A shoulder immobilizer or sling is a much better choice.
A long-arm gutter splint immobilizes the elbow (Figure 267-10). The upper extremity is placed in "sling position" (elbow flexed about 90 degrees and palm facing the abdomen). The splint begins on the ulnar surface of the hand at the metacarpal heads and extends along the ulnar surface of the forearm, past the elbow, to a spot high on the lateral surface of the upper arm just opposite and below the axillary crease. It should be supplemented with a sling.
The most common error associated with fashioning this dressing is insufficient length. If the splint is not carried far enough above the elbow, it will not exert enough leverage to prevent motion of that joint.
The long-arm gutter is useful for injuries about the elbow, including displaced radial head fracture, supracondylar humeral fracture, and reduced dislocation of the elbow.
The sugar-tong is a splint that prevents motion of the wrist and elbow, including pronation-supination (Figure 267-11). The upper extremity is placed in "sling position," as described in the preceding section Long-Arm Gutter Splint. The splint begins on the extensor aspect of the hand at the level of the metacarpal heads and runs along the extensor aspect of the forearm, around the elbow and humeral condyles, onto the flexor aspect of the forearm, and ultimately to the palmar aspect of the hand, ending at the level of the metacarpal heads. It is wrapped in place with gauze and often topped off with an elastic compression bandage. It should be supplemented with a sling.
Proper length of the sugar-tong dressing is important. Too short a splint will fail to immobilize the wrist. If the dressing is too long, it will impair motion of the metacarpophalangeal joints, leaving them stiff and making the fingers more susceptible to swelling due to immobility.
The sugar-tong splint is appropriate for fractures about the wrist or distal forearm. Some orthopedists use it as a definitive dressing after reduction of wrist fractures.
Cock-Up Wrist Splint (to Be Avoided)
A cock-up splint extends from the distal forearm to the proximal portion of the hand and maintains the wrist in a dorsiflexed position. It should not be used for fractures of the wrist or carpals because injuries to those areas usually are caused by forceful dorsiflexion, and a cock-up splint reproduces the position of injury, imposing considerable pain in the process. Generally, fractures about the wrist are immobilized in neutral position. Colles fractures may sometimes be immobilized in palmar flexion after reduction.
Cock-up splints may be useful in some situations not related to trauma, such as to immobilize the wrist for tendinitis or to support it in the case of wrist drop due to radial nerve palsy. In such instances, passive dorsiflexion of the wrist is indicated to preserve grip strength.
A short-arm gutter splint immobilizes the wrist and the ulnar or radial half of the hand (Figure 267-12). The ulnar gutter, for example, extends along the ulnar surface of the hand and forearm, beginning just proximal to the tip of the fifth finger and ending high on the forearm. It should be wide enough to encompass the fourth and fifth rays (phalanges and metacarpals) on the extensor and flexor aspects of the hand. The splint is wrapped in place so that the fourth and fifth fingers are bound together, with a thin layer of padding between them to prevent maceration of the skin. The metacarpophalangeal joints and interphalangeal joints are positioned in gentle flexion. The dressing may be supplemented with a sling.
Short-arm ulnar gutter splint.
The short-arm ulnar gutter is useful for fracture of the proximal phalanx of the ring or little finger or for fracture of the fourth or fifth metacarpal (including the common "boxer's fracture"). The counterpart of this splint, the short-arm radial gutter, is designed in similar fashion but extends along the radial surface of the hand and forearm and is used for comparable injuries of the index or middle rays. It can be fashioned with a hole that allows the thumb to pass through, or by splitting the distal end so the two halves can be run along the extensor and volar aspects of the index and middle rays while the thumb remains free.
A thumb spica immobilizes the wrist and the thumb (Figure 267-13). The term spica applies to any dressing that encompasses a main trunk plus one or more of its branches—in this case, the forearm plus the thumb. It is used for fracture of the scaphoid or for fracture of the thumb metacarpal or proximal phalanx.
A thumb spica may be fashioned from one wide splint that runs along the thumb and radial aspect of the wrist and forearm, but an even more effective dressing can be made from two separate non-prepadded plaster splints. The wrist piece runs along the extensor aspect of the hand and forearm, beginning at the metacarpal heads and ending just short of the antecubital crease. The more narrow thumb piece, approximately 2 in. wide, extends from the tip of the thumb, along the outer aspect of the thumb metacarpal, and onto the extensor aspect of the forearm, well overlapping the first splint. Along their area of contact, the two splints are molded into each other, with no padding between them, to form a sturdy dressing. The plaster is wrapped in place with gauze, and a compression wrap may be added at the clinician's discretion. The dressing may be supplemented with a sling.
This technique is not suiTable for prepadded splints with plaster or fiberglass already enclosed, as the two pieces cannot be molded into one another, which compromises the structural integrity of the dressing. When prepadded material is used, a single wide splint encompassing the thumb must suffice.
While the dressing is setting, optimal position may be achieved by keeping the wrist in neutral position and having the patient oppose the tips of the thumb and index finger in the form of an "OK" sign. This preserves thumb-to-index pinch function, so as to minimize the patient's incapacitation. The neutral position of the wrist also avoids reproducing the position of injury in the case of scaphoid fracture, which is typically caused by forced dorsiflexion.
The knee immobilizer is a removable circumferential device that extends from the thigh to just above the ankle (Figure 267-14). The splint contains longitudinal struts that, in some cases, may be repositioned as needed, and is secured with Velcro® straps.
A knee immobilizer maintains the knee in extension, the position of maximum stability. The device is useful for a variety of injuries, including fracture of the lateral or medial tibial plateau, fracture of the patella, meniscal injuries (provided the knee is not locked in partial flexion), and ligamentous strains or tears.
Use of an immobilizer for more than a few days in the elderly or for more than a week or two in young patients may result in painful stiffness of the knee joint. For that reason, orthopedic follow-up should occur within approximately 7 days. If immobilization is indicated beyond that point, the orthopedist may replace the original device with a cast brace or other orthosis that allows controlled and progressive range of motion.
Motion and Strength Exercises for the Knee Joint stiffness and instability due to quadriceps weakness may occur rapidly when the knee is immobilized. Patients wearing an immobilizer should be encouraged to remove the device periodically and perform the following exercises:
Passive flexion: While sitting on a flat surface, grasp the ends of a towel draped beneath the sole of the foot and pull upward, creating as much knee flexion as possible without undue pain.
"Gravity-assisted" flexion: While sitting on the edge of a bed or chair, support the knee in extension, with the well foot beneath the ankle of the injured extremity, then gradually lower the supporting foot so the injured knee "drops" into flexion. When tolerance is reached, bring the knee back into extension.
Quadriceps strengthening: While lying supine with a pillow beneath the knee, actively bring the knee to full extension in a straight leg raise, then relax.
Each of these exercises should be performed as multiple repetitions several times a day.
The posterior ankle mold is used to immobilize the ankle (Figure 267-15). It begins beneath the metatarsal heads, runs along the plantar aspect of the foot, and continues up the back of the lower leg, ending at high calf. The splint is used for fractures or severe sprains of the ankle. Support may be supplemented by a transverse sugar-tong component running down the lateral side of the lower leg, beneath the heel, and up the medial side. Where the two components overlap, they are molded together. (Non-prepadded plaster should be used in this situation). The transverse component helps minimize inversion and eversion of the ankle. Even more stability is provided by continuing the posterior splint past the back of the knee to the high posterior thigh, using wider splinting material for this area. With the knee slightly flexed, rotational motion at the ankle also will be prevented.
While the dressing is setting, the ankle should be maintained in a position as close as possible to neutral dorsiflexion—that is, at 90 degrees to the leg. This may facilitate regaining range of motion after the dressing is removed. Because most patients with ankle injuries tend to keep the ankle plantarflexed, the clinician usually will have to counteract this by exerting gentle pressure with a palm beneath the metatarsal heads. An exception to the 90-degree principle is immobilization for rupture of the Achilles tendon. Patients with this injury should be immobilized in plantar flexion to reduce tension on the tendon.
Easier to apply and less cumbersome for the patient than a posterior mold, the ankle stirrup (Figures 267-16A and 267-16B) is useful for sTable ankle sprains and for sTable lateral malleolus fractures. The ankle stirrup is essentially an air-padded "sugar-tong" splint held in place by Velcro® straps. Unlike the posterior mold, this device is intended for use in conjunction with weightbearing. It limits inversion more effectively than taping but allows normal plantarflexion and dorsiflexion. This feature and the graduated compressive effect of the air-filled bladders may result in less swelling and edema, less joint stiffness, and a faster return to comforTable ambulation than is typically observed after rigid immobilization.21
The stirrup may be removed for purposes of bathing or when not bearing weight. If the patient does remove the splint temporarily, a common error when reapplying it is to fail to unwrap the straps completely—specifically, to leave the straps attached posteriorly, so that the splint is "hinged like a book" along its posterior aspect. This may result in the foot persistently slipping forward and out of the splint. The clinician may wish to instruct the patient that the proper way to reapply the splint is to unwrap the straps all the way around, so that the sides fall apart bilaterally, with the heel pad acting as the "hinge" on the plantar aspect (Figure 267-17). The foot may then be positioned on the lower pad, and the sides reapplied to the medial and lateral aspects of the ankle and lower leg. The final step is to rewrap the straps around the dressing.
Technique for applying ankle stirrup.
Motion and Strength Exercises for the Ankle Exercises to restore range of motion, stability, and balance should be started as soon as possible after an ankle injury.
Active dorsiflexion and plantarflexion: When performed supine with the foot well elevated, this exercise may also enhance lymphatic drainage, thereby reducing swelling.
Passive dorsiflexion: One method for performing this exercise is to stand with the palms braced against the wall, then to bend the knee toward the wall while keeping the heel flat on the floor.
Eversion, dorsiflexion, and plantarflexion against resistance: This exercise may be accomplished by manually applying a counterforce with a stretchable elastic cord (commercially available). Standing on the toes is another means of resistive plantarflexion.
Each of these exercises should be performed as multiple repetitions several times a day.
A hard-soled shoe is a removable "sandal" with wrap-around sides usually secured with Velcro® and a flat, nonflexible sole (Figures 267-18A and 267-18B). This device is intended to allow weightbearing by patients with toe fractures or certain types of metatarsal fractures. The firm sole prevents the toes from bending and provides support for the forefoot. Although immobilization dressings may be warranted for some metatarsal fractures, the hard-soled shoe is an accepted treatment modality for fracture of the second, third, fourth, or proximal fifth metatarsal.22,23
The pneumatic walking brace is a device that provides firm support about the foot, ankle, and lower leg. It is available in high-top or short-top varieties. The high-top walker (Figure 267-18C), which extends almost to the knee, is suiTable for injuries such as moderate to severe ankle sprains or for sTable fractures of the foot or ankle. Short-top walkers extend just above the ankle joint and may be used for phalangeal or sTable metatarsal fractures.
A, B. Hard-soled shoe. C. Pneumatic walking brace.
The term pneumatic refers to the fact that the inner lining of the brace is inflatable. Though non-pneumatic models are available, the pneumatic component has at least two advantages. It provides added compression, which helps reduce swelling and pain, and allows the walker to conform more closely to the contour of the extremity, which enhances immobilization.