Volar Splinting

In general, splints are applied to decrease movement and provide support and comfort through stabilization of an injury. They are primarily used to stabilize nonemergency injuries to bones until the patient can be evaluated by a consultant (eg, an orthopedic surgeon). Splints are also used to assist in primary healing or to temporarily immobilize an extremity before surgery (eg, for open fracture).[1]

Unlike casts, splints are noncircumferential. They are often preferred in the emergency department (ED) setting, where injuries are frequently acute and continued swelling can occur. All patients with injuries that are splinted should be referred for evaluation by a consultant in a timely fashion (usually within 2-7 days, depending on the reason for splinting).[2, 3]

A volar splint can be used for various injuries,[4] including the following:

• Soft-tissue injuries of the wrist and hand ^[5]
• Fractures of the second, third, and fourth metacarpals
• Fractures of the second, third, and fourth phalanges
• Positioning for rheumatoid arthritis
• Certain wrist fractures, including a pisiform fracture
• Positioning in the treatment of carpal tunnel syndrome (median nerve compressive neuropathy), ^{[6, 7, 8, 9]}  sometimes in conjunction with a metacarpophalangeal (MCP) unit ^[10]

There are no absolute contraindications for volar splinting. Relative contraindications in injuries that require immediate evaluation or intervention by a consultant (eg, an orthopedic surgeon, hand surgeon, or plastic surgeon) include the following:

• Complicated fractures
• Open fractures
• Injuries with associated neurovascular compromise

Equipment used in volar splinting includes the following:

• Stockinette
• Padding (eg, Webril)
• Plaster - 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
• 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

Alternatively, prefabricated fiberglass (eg, Orthoglass) can be used in place of the stockinette, plaster, and padding. (See the image below.)

Equipment for volar splinting. Image courtesy of Kenneth R Chuang, MD.

Meals et al tested seven different volar wrist splint designs (70 splints, including 10 of each design) in an effort to determine whether splint material (plaster or fiberglass), thickness (eight-, 10-, or 12-ply), or longitudinal ridging (with or without) affected the strength of the splint.[11] They found that for the plaster splints, more layers of material and the addition of longitudinal ridging increased splint strength. Ridged eight-ply plaster splints were stronger than nonridged 10-ply plaster splints. Fiberglass splints were comparable to ridged eight-ply plaster splints in strength and thus might be a lighter, similarly effective, and cheaper alternative.

Anesthesia

Splinting 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 ^[12]
• Administration of oral or intravenous (IV) pain medications, including nonsteroidal anti-inflammatory drugs (NSAIDs) or opioid analgesic agents

With the administration of any analgesic agent or the initiation of a formal sedation protocol, care must be taken to avoid oversedation. A complete neurovascular examination should be performed after the splint has been applied.

Positioning

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 first video below.) Completely expose the injured limb. Remove all jewelry (see the second video below). 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.

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

Position the patient as previously described (see Periprocedural Care, Patient Preparation).

Apply the stockinette (see the video below). 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 should be pulled over the edges of the wet plaster to create smooth edges.

Wrap the padding (eg, Webril) over the stockinette (see the video below). 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 and to the base of the thumb.

Measure the plaster (see the video below). For an adult of average size, plaster for the volar splint should be eight to 10 layers thick. Use plaster that is 3-4 in. (7.5-10 cm) wide. After counting out the layers, measure the plaster from the level of the metacarpal heads to the proximal third of the forearm. Allow for roughly 5 mm of extra length on either end; the plaster shrinks when wet. Fold over excess wet plaster on the ends.

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 (see the video 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 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.

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

Apply the bandage wrap over the wet plaster, starting distally and wrapping proximally (see the video below). Cut an adequate hole for the thumb. Avoid wrapping too tightly.

While the plaster is still wet, mold the splint into the desired shape (see the video below). The wrist and hand should be in a neutral position. Extend the wrist to 20°, abduct the thumb, and flex the metacarpophalangeal (MCP) joints to 70°. To assist in achieving a 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.

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.

After the splint has dried, check for neurovascular function and capillary refill (see the video below). Recall that the median nerve provides sensory function to the palmar side of the thumb; the second, third, and lateral half of the fourth digits; and, dorsally, to the distal half of the second, third, and lateral half of the fourth digits. The ulnar nerve provides sensory function to the palmar and dorsal aspects of the fifth digit and the medial half of the fourth digit. The radial nerve provides sensory function to the dorsal surface of the hand and to the web space between the first and second digits. Remember to check motor function as well. Wipe away any plaster that may have dropped onto the patient's skin.

Deliver appropriate aftercare instructions. Advise 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.

Instruct the patient to keep the splint clean and dry and not to stick any items into it. 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 injuries or cause a break in the skin and lead to an unattended infection. (See the image below.)

Volar splint. Image courtesy of Kenneth R Chuang, MD.

Arrange for follow-up with a consultant, usually within 2-7 days, depending on the reason for the splint.

If the patient received any sedation or opioids, advise against driving and/or alcohol consumption.

Thermal burns

Patients can expect to feel some warmth as the plaster dries. However, if the patient experiences intense heat or any pain, remove the plaster immediately; thermal burns can occur.[13] As more layers of plaster are used, more heat is produced.[14, 15]  Use clean room-temperature water; water that is dirty or too warm decreases drying time and increases the heat produced.[14]  Do not wrap towels or blankets around the splint to shorten drying time; this produces excess heat.

Pressure injuries

To prevent pressure injuries, provide extra padding to bony prominences. When wrapping the cotton padding, avoid creases; if creases occur, smooth them out or unwrap and rewrap, as needed. When molding the wet plaster, use broad-based pressure—in other words, apply pressure by using the entire palmar surface of the hands and fingers, not the fingertips.

Contact dermatitis

Consider prescribing an antihistamine (eg, diphenhydramine) for itching. However, if the itching persists or worsens, evaluate the splint for complications. (For more information, see Irritant Contact Dermatitis.)

Ischemia and neurovascular compromise

These conditions can be caused by increased pressure from swelling. If moderate-to-significant swelling is anticipated, cut the cotton padding lengthwise, on the ventral side of the forearm, before applying the wet plaster to the volar side. This allows for expansion of the padding. If using tape to secure the outermost bandage wrap, do not tape circumferentially.

The median nerve runs in the carpal tunnel on the volar aspect of the wrist. Compression of the median nerve can lead to pain, numbness, paresthesias, and weakness in the median nerve distribution (sensory function to the palmar side of the thumb, second, third, and lateral half of the fourth digits and, dorsally, to the distal half of the second, third, and lateral half of the fourth digits). If compression of the nerve is suspected, immediately remove the splint and perform another neurovascular examination. Consider consultation if symptoms do not subside.

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 (ROM), despite best care practices. Physical therapy is often required in the aftercare of such injuries.