Ulnar Gutter Splinting Technique

Explain the procedure to the patient, including risks and benefits. Obtain informed consent.

With the patient appropriately positioned (see Positioning), apply the stockinette. Cut longitudinally at the distal end of the stockinette to allow coverage of the fourth and fifth digits. Then, cut an adequate hole for the thumb, being careful to avoid constriction of the thumb. (See the video below.)

When measuring the stockinette, allow for extra 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.

Next, place a piece of padding between the fourth and fifth digits; this helps prevent maceration of the skin. Wrap the padding over the stockinette. Overlap each layer by half the width. Also, allow for extra length. The padding should extend 2-3 cm beyond the overlying plaster on both ends. Smooth out creases, unwrapping and rewrapping as necessary. Apply extra padding to the bony prominences of the wrist, the metacarpophalangeal (MCP) joints, and the interphalangeal (IP) joints. (See the video below.)

Measure the plaster. For an adult of average size, the plaster for an ulnar gutter splint should be eight to 10 layers thick. Use plaster that is 3-4 in. wide. After counting out the layers, measure the plaster from the fifth distal IP (DIP) joint to the proximal third of the forearm. Allow for roughly 5 mm of extra length on either end; plaster shrinks when wet. Excess wet plaster on the ends will be folded over. (See the video below.)

If prefabricated fiberglass is being used, the stockinette and padding steps can usually be skipped. In this case, follow the manufacturer's recommendations.

Submerge the plaster in clean, room-temperature water. 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 the remaining water. Then, lay the plaster on a flat surface or dry towel and smooth out wrinkles and folds. This allows further bonding of the plaster layers. (See the video below.)

Apply the wet plaster, over the padding, to the medial or ulnar surface of the forearm. The plaster should extend from the DIP joint to the proximal third of the forearm. Fold the excess plaster outward on the ends. Then, fold the underlying stockinette and padding outward on both ends in such a way as to create smooth edges. (See the video below.)

Apply the bandage wrap over the wet plaster. Start distally, at the DIP joints of the fourth and fifth digits, and wrap proximally. Cut an adequate hole for the thumb. Avoid wrapping too tightly. (See the video below.)

While the plaster is still wet, mold the splint into the desired shape. The wrist and hand should be in a neutral position. To assist in achieving neutral position of the hand and wrist, some clinicians advocate having the patient hold a can or a bandage wrap. Alternatively, the patient can imagine holding a wine glass.

Extend the wrist to 20°, and flex the MCP joints to 70°. The patient's hand, wrist, and forearm 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. (See the video below.)

Once the splint is dry, check for neurovascular function and capillary refill. Wipe away any plaster that may have dropped onto the patient's skin. (See the video below.)

Deliver appropriate aftercare instructions. 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.

Keep the splint clean and dry. Do not stick any items into the splint. Patients can be tempted to use sticks, pens, or hangers to scratch an itch. 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 opioids, advise against driving or alcohol consumption.

Patients can typically expect to feel some warmth as the plaster dries. ^[6]  However, if intense heat or any pain is reported, the plaster should be removed immediately to prevent possible thermal burns. ^[7]  As more layers of plaster are used, more heat is produced. 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 produces excess heat.

To prevent 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 to mold the plaster.

Contact dermatitis may develop with ulnar gutter splinting. Consider prescribing an antihistamine (eg, diphenhydramine) for itching. However, if the itching persists or worsens, evaluate the splint for complications.

Increased pressure from swelling may give rise to ischemia and neurovascular compromise. If moderate-to-significant swelling is anticipated, cut the cotton padding lengthwise along the lateral or radial side of the forearm before applying the wet plaster on the ulnar side. This allows for expansion of the padding. If using tape to secure the outermost bandage wrap, do not tape circumferentially.

Immobilization may result in decreased range of motion. 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.