Ulnar Gutter Splinting 

Splints are generally applied to decrease movement to provide support and comfort through stabilization of an injury. The primary purpose of a splint is as a temporary bridge for nonemergent injuries to bones until definitive casting can be performed by a consultant, such as an orthopedic surgeon. Splints can also serve as initial immobilization in the presurgical period or as immobilization for primary healing.^{[1, 2]} All patients with injuries that are splinted should be referred for evaluation by a consultant in a timely fashion, usually within 2-3 days.

An ulnar gutter splint can be used for various injuries to the upper extremities, including the following:

• Soft tissue hand injuries to the fourth and fifth fingers
• Fourth and fifth metacarpal fractures
• Fractures of the fourth and fifth phalanges
• Positioning for rheumatoid arthritis

Although no true contraindications exist to the placement of a splint, certain injuries require immediate evaluation or intervention by a consultant (eg, orthopedic surgeon, hand surgeon, plastic surgeon) and, as such, may not necessitate splinting. Such injuries include the following:

• Complicated fractures
• Open fractures
• Injuries with associated neurovascular compromise
• Metacarpal angulation (In an otherwise uncomplicated metacarpal fracture, 10° of angulation are acceptable in the second and third metacarpal, 20° in the fourth metacarpal, and 30° in the fifth metacarpal. Greater angulation often requires surgery; such injuries need the immediate evaluation or intervention of a consultant.)

Splinting itself is usually tolerated without the use of anesthesia. However, if significant manipulation or reduction of the injury is required during the splinting process, anesthetic techniques may be used. Acceptable techniques include the following:

• Administration of a hematoma block or nerve block
• Procedural sedation with appropriate monitoring and administration by an experienced physician^[3]
• Administration of oral or intravenous pain medications, including nonsteroidal anti-inflammatory drugs (NSAIDs) or opioid analgesic agents

With the administration of any analgesic agent or initiation of a formal sedation protocol, take care to avoid oversedation. Perform a complete neurovascular examination before and after the splint has been applied.

• Stockinette
• Padding (eg, Webril)
• Bandage or wrap (eg, bias bandage or Ace bandage)
• Clean, room-temperature water in a basin
• Trauma shears or a pair of medical scissors without pointed ends
• Chux pads and bed sheet
• Tape or bandage clips
• Plaster or prefabricated fiberglass splint material (See the image below.)Equipment for splint. Image courtesy of Kenneth R. Chuang, MD.

• Place the patient in a comfortable position (eg, seated or reclined).
• Cover the patient with a sheet to avoid splatter from the wet plaster. See the video below.

  Cover patient appropriately. Video courtesy of Kenneth R. Chuang, MD.
• Completely expose the injured limb. Remove all jewelry. In particular, rings can cause constriction and ischemia of the fingers with delayed swelling of the soft tissues. If unable to remove a ring, try using soap as a lubricant or consider a ring cutter. See the video below.

  Remove jewelry and rings to avoid ischemia from swelling. Video courtesy of Kenneth R. Chuang, MD.

• Explain the procedure to the patient, including risks and benefits. Obtain informed consent.
• Position the patient as described above. See Positioning.
• Apply stockinette. Cut longitudinally at the distal end of the stockinette to allow covering for the fourth and fifth digits. Then, cut an adequate hole for the thumb, being careful to avoid constriction of the thumb. 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. See the video below.

  Stockinette application for ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• Begin by placing a piece of padding (eg, Webril) between the fourth and fifth digits. This helps prevent maceration of the skin. Then, 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 joints, and the interphalangeal joints. See the video below.

  Cotton padding application for ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• Measure the plaster. For an adult of average size, plaster for the ulnar gutter splint should be 8-10 layers thick. Use plaster that is 3-4 in wide. After counting out the layers, measure the plaster from the fifth distal interphalangeal joint to the proximal third of the forearm. Allow for roughly 5 mm of extra length on either end, as plaster shrinks when wet. Excess wet plaster on the ends will be folded over. See the video below.

  Measuring dry plaster for ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• If using prefabricated fiberglass, the stockinette and padding steps can usually be skipped. In this case, follow the manufacturer 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 for further bonding of the plaster layers. See the video below.

  Wetting the plaster for ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• Apply the wet plaster, over the padding, to the medial or ulnar surface of the forearm. The plaster should extend from the distal interphalangeal joint to the proximal third of the forearm. Fold outward excess plaster on the ends. The underlying stockinette and padding should then be folded outward on both ends, creating smooth edges. See the video below.

  Applying wet plaster for ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• Apply the bandage wrap over the wet plaster. Start distally, at the distal interphalangeal (DIP) joint of the fourth and fifth digits, and wrap proximally. Cut an adequate hole for the thumb. Avoid wrapping too tightly. See the video below.

  Applying bandage wrap for ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• While the plaster is still wet, mold the splint into the desired shape. The wrist and hand should be in a neutral position. Extend the wrist to 20° and flex the metacarpophalangeal joints to 70°. The 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.

  Molding the ulnar gutter splint. Video courtesy of Kenneth R. Chuang, MD.
• Check for neurovascular function and capillary refill after the splint has dried. Wipe away any plaster that may have dropped onto the patient's skin. See the video below.

  Test neurovascular function and capillary refill. Video courtesy of Kenneth R. Chuang, MD.
• 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. See the image below.Ulnar gutter splint. Image courtesy of Kenneth R. Chuang, MD.

• 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. With either method, maintain the wrist at 20° extension.
• For injuries or reductions that require shorter drying times, faster-setting plaster is available (eg, Specialist Extra Fast Setting Plaster). However, as plaster dries faster, the risk of thermal injury increases. For most splints, regular plaster (eg, Specialist Fast Setting Plaster) is appropriate.
• Consider prescribing an antihistamine (eg, diphenhydramine) for itching. However, if the itching persists or worsens, evaluate the splint for complications.
• Malrotation can be a difficult finding to confirm by radiograph. The best method of confirmation is clinical examination. With the second to fifth fingers slightly flexed, the nail beds of adjacent fingers should lie in the same plane. With 90° flexion of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP), and with distal interphalangeal (DIP) extension, the second to fifth fingers should point toward the scaphoid. Also compare with the unaffected hand. Any degree of malrotation usually requires surgical intervention.
• In the conventional anatomical position, with the palms facing anteriorly, the medial side of the fourth digit is the ulnar side. The ulnar nerve provides sensory function to the palmar and dorsal aspects of the fifth digit and the medial half of the fourth digit.

• Thermal burns:^[4] Patients can expect some warmth as the plaster dries. However, if the patient experiences intense heat or pain, remove the plaster immediately.

  • As more layers of plaster are used, more heat is produced.^[5]
  • Use clean, room-temperature water. Water that is dirty or too warm decreases drying time and increases the heat produced.
  • Do not wrap towels or blankets around the splint to shorten drying time. This produces excess heat.
• 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: See eMedicine article Contact Dermatitis.
• Ischemia and neurovascular compromise: These complications may be caused by increased pressure from swelling. If moderate to significant swelling is anticipated, cut the cotton padding lengthwise along the lateral or radial side of the forearm before application of the wet plaster to the ulnar side. This allows for expansion of the padding. If using tape to secure the outermost bandage wrap, do not tape circumferentially.
• Decreased range of motion from immobilization: Advise patients that, depending on the extent and nature of the initial injury, they 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.