Overview
Introduction
Splints are primarily used to stabilize injuries to bones until the patient can be evaluated by a consultant, such as an orthopedic surgeon,[1] as well as to achieve immobilization for primary healing or in the presurgical period. All patients with injuries that are splinted should be referred for evaluation by a consultant in a timely fashion (usually within 2-3 d). In general, ankle splints are applied to minimize movement and provide support and comfort by stabilizing an injury at that joint.
Indications
A posterior ankle splint is primarily used for the following injuries:
- High-grade ligamentous sprain of the ankle
Contraindications
No contraindications to ankle splinting are absolute. The following conditions demand immediate evaluation or intervention by a consultant (eg, orthopedic surgeon), as treatment by splinting alone is inadequate:
- Complicated fracture
- Open fractures
- Injuries with associated neurovascular compromise
Relevant Anatomy
The ankle joint is a hinged synovial joint with primarily up-and-down movement (plantar flexion and dorsiflexion). However, when the ranges of motion (ROMs) of the ankle and subtalar joints (talocalcaneal and talocalcaneonavicular) are taken together, the complex functions as a universal joint (see the image below).
Anatomy of the lateral ankle ligamentous complex and related structures. The combined movement in the dorsiflexion and plantarflexion directions is greater than 100°; bone-on-bone abutment beyond this range protects the anterior and posterior ankle capsular ligaments from injury. The anterior and posterior ankle capsular ligaments are relatively thin compared with the medial and lateral ankle ligaments.
For more information about the relevant anatomy, see Ankle Joint Anatomy.
Preparation
Anesthesia
Ankle splinting is usually tolerated without the use of anesthesia. However, if significant manipulation or reduction of the injury is required during the splinting process, one of the following anesthetic techniques may be used[3] :
- Hematoma block or nerve block
- Procedural sedation with appropriate monitoring and administration by an experienced practitioner[4] (for more information, see Procedural Sedation)
- Oral or intravenous analgesics (eg, nonsteroidal anti-inflammatory drugs [NSAIDS], opioids)
With the administration of any analgesic agent or the initiation of a formal sedation protocol, care should be taken to avoid oversedation. A complete neurovascular examination should be performed before and after the splint has been applied.
Equipment
The equipment involved in ankle splinting includes the following:
- Stockinette
- Padding (eg, Webril)
- Ready-made plaster or fiberglass splinting material or plaster splinting material (eg, plaster of Paris), 10-12 sheets (15-20 sheets if allowing the patient to bear partial weight), 4-6 inches wide
- Bandage or wrap (eg, Bias bandage or ACE wrap), 3-4 inches wide
- Clean, room-temperature water in a basin
- Trauma shears or a pair of medical scissors without pointed ends
- Disposable (Chux) pads and bed sheet
- Tape (if using Bias bandage) or bandage clips (if using non-Velcro ACE wrap)
- Equipment displayed in image below
Equipment for splint. Image courtesy of Kenneth R. Chuang, MD.
Positioning
Place the patient comfortably in the prone position, with the affected limb in 90° of knee flexion (see the brief video presentation below). Cover the patient with a sheet to avoid splatter from the wet plaster.
Position the patient prone, with knee flexed to 90 degrees. Cover the patient appropriately. Video courtesy of Kenneth R. Chuang, MD.Technique
Overview
Explain the procedure to the patient, including risks and benefits, and obtain written informed consent.
Position the patient as described previously (see Positioning).
Completely expose the injured limb. Remove clothing on the affected extremity or warn the patient that it may need to be removed with scissors after the splint is placed. Jewelry should also be removed. In particular, toe rings can cause constriction and ischemia of the toes with delayed swelling of the soft tissues. If a ring resists removal, try using soap as a lubricant or consider a ring cutter.
Apply the stockinette (see the brief video presentation below). The stockinette should extend from the toes to the proximal calf. When measuring the stockinette, cut longer than the expected splint length. The stockinette should extend 2-3 cm beyond the overlying padding on either end. In turn, the padding should extend 2-3 cm beyond the overlying wet plaster on either end. Together, the stockinette and padding will be pulled over the edges of the wet plaster to create smooth edges.
Stockinette application for posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.Wrap the padding (eg, Webril) over the stockinette (see the brief video presentation below). Begin distally and wrap proximally, overlapping each layer by half the width. The padding should extend 2-3 cm beyond the overlying plaster on both ends. Smooth out creases and avoid wrinkles, unwrapping and rewrapping as necessary. Narrower padding should be used for the foot and ankle to compensate for the angulation of the joint and to prevent wrinkling.
Cotton padding application for posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.Measure the plaster (see the brief video presentation below) with a roll plaster that is 3-4 inches wide. Using dry plaster, measure the first layer of plaster from the proximal calf to the metatarsal heads. Allow for roughly 5 mm of extra length on either end, as plaster shrinks when wet.
With the desired length pinched off, fold over the plaster. Begin unrolling the plaster and folding until the splint is 10-12 layers thick, for the average-sized adult. In children, who may be especially active and are frequently noncompliant with instructions, additional layers provide added stability.
If prefabricated fiberglass is used, the stockinette and padding steps can usually be skipped. In such cases, follow the manufacturer’s recommendations.
Measuring dry plaster for posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.Submerge the plaster in clean, room-temperature water (see the brief video presentation below). Allow all the bubbles to escape. This starts the lamination process of the plaster and allows the layers to bond together. Squeeze out the excess water. With the fingers, pull out any remaining water. Then, lay the plaster on a flat surface or dry towel, and smooth out wrinkles and folds. This allows for further bonding of the plaster layers.
Wetting the plaster for posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.Position the affected leg with the knee flexed and the ankle in 90° of dorsiflexion. Apply the wet plaster over the padding posteriorly from the high calf to the level of the metatarsals (see the brief video presentation below). Fold the excess plaster at the edges circumferentially and smooth the overlapped plaster at the level of the ankle. The underlying stockinette and padding should then be folded over the plaster on both ends, creating smooth edges.
Applying wet plaster for posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.Apply the bandage wrap over the wet plaster (see the brief video presentation below). Start distally and wrap proximally. Avoid wrapping too tightly. Be sure to completely cover the heel.
Applying bandage wrap for posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.While the plaster is still wet, mold the splint into the desired shape (see the brief video presentation below). While placing pressure on the sole of the foot with one palm to maintain 90° of dorsiflexion, use the other hand to mold the rest of the splint. The splint must maintain as close to 90° of dorsiflexion as possible.
The foot and ankle should remain immobile until the splint is dry. Advise the patient that he or she may feel some warmth released from the plaster as it dries. However, if the heat becomes too intense, unwrap the splint and remove the plaster immediately. Thermal burns can occur.
Molding the posterior ankle splint. Video courtesy of Kenneth R. Chuang, MD.Check neurovascular function after the splint has dried. The patient should not lose sensation in the toes. Peripheral vascular assessment can be accomplished by checking capillary refill. Ask the patient to wiggle the toes to assess motor function. Wipe away any plaster that may have dropped onto the patient's skin.
Post-Procedure
Deliver appropriate aftercare instructions, and instruct the patient to rest, elevate, and ice the injured limb. Instruct the patient to remove the splint and return immediately, or go to an emergency department, if he or she experiences weakness or numbness, color change (pale or bluish), increasing pressure or pain, or spreading redness or streaking.
The splint must be kept clean and dry.
Patients can be tempted to use sticks, pens, or hangers to scratch an itch inside the splint. Advise the patient that sticking objects into the splint can wrinkle the padding and lead to pressure sores or cause a break in the skin and lead to an unattended infection.
The splint should be rechecked in 48 hours. Also, arrange for follow-up with a consultant, usually in 2-3 days.
If the patient received any sedation or opioid agents, advise against driving or alcohol consumption.
Complications
Despite best-care practices, complications may arise from the splinting process.
Thermal burns
Thermal burns may occur.[5] Patients can expect some warmth as the plaster dries. However, if they report intense heat or any pain, remove the plaster immediately. As more layers of plaster are used, more heat is produced.[6]
Use clean, room-temperature water. Water that is dirty or too warm accelerates the drying time and increases the heat produced. Do not wrap towels or blankets around the splint to shorten drying time. This also produces excess heat.
Pressure sores
To avoid pressure sores, provide extra padding to bony prominences. When wrapping the cotton padding, avoid creases. When creases occur, smooth them out or unwrap and rewrap as needed. When molding the wet plaster, use broad-based pressure. In other words, do not use the fingertips; rather, use the entire palmar surface of the hands and fingers.
Contact dermatitis
This reaction may occur from any of the equipment used in the splinting process. See Contact Dermatitis.
Ischemia and neurovascular compromise
These complications may result from increased pressure from swelling. If moderate to significant swelling is anticipated, cut the cotton padding lengthwise along the lateral side of the calf before applying the wet plaster to the medial side. This allows for expansion of the padding. Also, if using tape to secure the outermost bandage wrap, do not tape circumferentially.
Decreased range of motion from immobilization
Advise the patient that, depending on the extent and nature of the initial injury, he or she can often expect long-term pain, arthritis, stiffness, and decreased range of motion, despite best care practices. The aftercare of such injuries often requires physical therapy.
Howes DS, Kaufman JJ. Plaster splints: techniques and indications. Am Fam Physician. Sep 1984;30(3):215-21. [Medline].
Hatch RL, Alsobrook JA, Clugston JR. Diagnosis and management of metatarsal fractures. Am Fam Physician. Sep 15 2007;76(6):817-26. [Medline].
[Best Evidence] White BJ, Walsh M, Egol KA, et al. Intra-articular block compared with conscious sedation for closed reduction of ankle fracture-dislocations. A prospective randomized trial. J Bone Joint Surg Am. Apr 2008;90(4):731-4. [Medline].
Sacchetti A, Senula G, Strickland J, et al. Procedural sedation in the community emergency department: initial results of the ProSCED registry. Acad Emerg Med. Jan 2007;14(1):41-6. [Medline].
Kaplan SS. Burns following application of plaster splint dressings. Report of two cases. J Bone Joint Surg Am. Apr 1981;63(4):670-2. [Medline].
Halanski MA, Halanski AD, Oza A, et al. Thermal injury with contemporary cast-application techniques and methods to circumvent morbidity. J Bone Joint Surg Am. Nov 2007;89(11):2369-77. [Medline].
Hutchinson MJ, Hutchinson MR. Factors contributing to the temperature beneath plaster or fiberglass cast material. J Orthop Surg. Feb 25 2008;3:10. [Medline].
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