Short-Arm Splinting 

Background

Short-arm splinting is most commonly used for initial support of the injured extremity (whether planned for surgery or not) and for postoperative immobilization of internally fixed fractures. There are several different types of short-arm splints. Each lends itself to a specific subset of orthopedic injuries and issues.

Indications

Several indications exist for short-arm splinting. This technique can be used to immobilize joints of the hand and wrist or to protect bony and soft tissues in the forearm.

Short-arm splints are often used as a means of temporary or preoperative support for a variety of injuries. Bony, ligamentous, or severe soft-tissue injures to the hand located at the base of the fingers (proximal phalanx) or above (proximal) are adequately immobilized by short-arm splints. Any injury of the fourth or fifth proximal phalanges, metacarpals, ulnar side of the wrist, or distal ulna are amenable to an ulnar gutter splint, a specific type of short-arm splint. Injuries to the second and third proximal phalanges, metacarpals, or distal radius may be held with a radial gutter splint.^[1]

Although distal radius fractures are commonly immobilized in sugar tong splints, Bong et al. showed that radial gutter splints were equally efficacious in maintaining the initial reduction and were better tolerated by patients.^[2]

Thumb spica splints can be used to temporarily stabilize scaphoid fractures and a variety of bony and ligamentous injuries to the thumb and first metacarpal. Volar and dorsal slab splints (anterior-posterior splints) covering the palmar/dorsal aspect of the metacarpals, wrist, and distal forearm are useful for protecting soft-tissue injuries, some carpal bone fractures (excluding scaphoid), and childhood buckle fractures.

Short-arm splints are less frequently used for definitive treatment, yet there is some support in the literature for long-term use. Short-arm support with a removable, prefabricated splint has been shown to be as effective as casting in the treatment of pediatric buckle and minimally displaced distal radius fractures while resulting in less complications and higher patient satisfaction.^{[3, 4]} Short-arm splinting has even been suggested for use in minimally displaced adult distal radius fractures.^[5] Adult ulna fractures that are minimally displaced may be treated in a functional brace. Prefabricated wrist splints are often used in the treatment of carpal tunnel syndrome.

For fractures and ligamentous injuries that are accompanied by open wounds or burns, a splint may be used instead of a cast for definitive treatment. The splint allows easier access to the superficial tissues while still treating the bony or ligamentous injury. Removable wrist splints may also be used as the definitive treatment for mild carpal tunnel syndrome and sprains of the wrist.

Short-arm splints are also placed after the completion of definitive surgical fixation in order to protect the surgical site. For the most part, these postoperative indications are dependent on the surgeon’s preference. They tend to mimic the indications for preoperative and temporary fixation (eg, a thumb spica splint after thumb/first metacarpal surgery, a volar slab after carpal tunnel release). These postoperative splints are used to protect the incision, as well as to temporarily immobilize the recently repaired anatomy.

Contraindications

The contraindications for splinting are relatively sparse. On occasion, the soft-tissue injuries accompanying fractures may be so severe as to make splinting for anything longer than a few hours impractical. These severe soft-tissue injuries would normally necessitate prompt operative intervention.

Following some procedures, particularly those involving the microvasculature, splints may interfere with the required monitoring, but a splint can usually be modified so as to allow for this. If frequent wound care is required, a removable splint is generally used.

In cases of decreased ability to feel the skin (neuropathy), both splinting and casting can lead to skin breakdown without the patient realizing. Skin checks are recommended to minimize the chance of such ulceration. Finally, long-term splinting across joints can lead to stiffness and sometimes permanent loss of joint motion, especially in the joints of the hand and fingers.

Technical Considerations

Best Practices

Short-arm splints should not be used when prevention of pronation and supination is necessary. In this case, a sugar-tong splint, a long-arm splint, or a long-arm cast should be considered.

The decision to apply a splint rather than a cast requires several considerations. Although casts provide more support by virtue of their circumferential nature, they can be more difficult to apply. In addition, applying rigid circumferential material in an acute injury setting does not allow for the variations in swelling that may take place. Thus, casting in the face of an acute injury runs the risk of neurovascular compromise, skin pressure ulceration, and compartment syndrome. Although these conditions are still possible in a splint, especially a poorly applied splint, they are more likely to occur with casting.

In the majority of conditions, splinting should not be a long-term treatment. In the setting of acute injuries, splints are often applied as a means of temporary stabilization either preoperatively or until a cast can be applied. In this case, follow-up should be arranged promptly (usually in less than 2 weeks) both to monitor the splint and to arrange for definitive care. Earlier follow-up or even constant monitoring on an inpatient basis can be considered for those patients with severe injuries requiring prompt operative intervention, or those patients in whom pain and neurovascular status are difficult to monitor due to pre-existing neurological conditions or inability to communicate.

Although there is some variability in the literature, full-time splint wear leads to more symptomatic and functional improvement than nighttime wear alone.^[6]

Procedure Planning

The first steps in applying a splint involve preparing the patient. Before any splint application, especially those involving a reduction of a fracture or a joint dislocation, the neurovascular status of the injured extremity must be determined and documented. The arm should be clean and dry, and any open wounds should be irrigated and addressed.

Complication Prevention

Most complications of splinting can be avoided by proper splint application. Extremes of flexion or extension are avoided to prevent discomfort and muscle or tendon damage. Proper padding of the splint at all bony prominences can help prevent pain, irritation, thermal burns, and pressure sores. The neurovascular status of the arm is monitored during and after the splinting procedure.

Proper splint application for fractures involves a 3-point mold technique. Attention to this detail can prevent loss of reduction in some less stable fractures. Special consideration should be made for any patient in whom it will be difficult to monitor discomfort and neurovascular status after splinting. If a patient is unable to communicate the pain that they feel, careful splint application and prompt follow-up are important to avoid complications.

Prolonged splint immobilization of joints can lead to stiffness and permanent loss of motion, and this issue should be considered when arranging follow-up. Pressure sores and skin breakdown are common complications of splint usage. These can usually be avoided by proper splint application and patient follow-up. Adequate padding of the splint can dramatically decrease the risk. Any splint that gets dirty or wet should be changed; these conditions increase the risk of skin breakdown and infection.

The most serious complication of splints is the potential for compartment syndrome. This condition is less common in the upper extremity than the lower extremity. Its incidence is lower when using a splint rather than a circumferential cast. However, if a splint is applied incorrectly, compartment syndrome can still occur, especially after severe trauma to the forearm.

Several mistakes in splint application can increase the chances of compartment syndrome: circumferential application of nonstretching cotton gauze over an open wound (blood can cause the cotton to harden and restrict swelling), failure to place the arm in the position of function, and excessively tight wrapping over the splint.

The most important aspect of splint application in avoiding compartment syndrome is careful monitoring of the patient. Any changes in neurovascular status should be considered an urgent indication for splint removal and reexamination. In addition, a splinted arm, especially after reduction of a displaced fracture, should be more comfortable than before. Therefore, increasing pain in a splinted extremity should also be cause for concern.

Patient Education & Consent

Patients should be instructed on proper splint care. The splint should be kept clean and dry. Plaster will break down if submerged in water and the splint will no longer provide stability. Fiberglass will not weaken, but the cotton padding inside will become wet and remain so against the skin. This can contribute to skin breakdown.

On occasion, a splint may be applied in a manner that leads to undue pressure or abrasion at certain areas of the skin. Patients should be instructed not to modify the splint on their own, but to return to their health care provider promptly so their splint can either be modified or changed.

Most importantly, patients should be instructed on the symptoms of possible compartment syndrome. Pain that seems to be out of proportion to the injury or that increases after splinting is the primary early symptom of an impending compartment syndrome. Changes in neurovascular status such as dusky or pale fingertips, numbness, or tingling are late signs of compartment syndrome. Permanent damage may have occurred by the time these symptoms manifest.

Equipment

Certain supplies are needed to apply a short-arm splint of any kind. Cast padding, splinting materials (plaster or fiberglass), and water are all that is truly needed to apply a proper splint. For some fractures, especially distal radius fractures, the use of finger traps and weights hung from the arm may facilitate fracture reduction and splint application through ligamentotaxis. See the image below.

Splinting material can be either plaster or fiberglass. Plaster is cheaper and generally considered easier to apply because of its superior flexibility compared with fiberglass.^[7] Both generate heat during the process of setting and carry a risk of thermal burn during application.

Fiberglass is more radiolucent and lighter, making it desirable to both the patient and physician. However, the increased cost and difficulty of application may offset these benefits. For most situations in the upper extremity (usually temporary fixation), a well-padded plaster splint is sufficient.

Patient Preparation

Anesthesia

The type of anesthesia required for splint application depends on the injury and patient’s condition. In most acute injuries to the forearm and hand, a splint can be applied using only local or regional anesthesia. On rare occasions, moderate sedation may be required in order to properly apply the splint without undue patient discomfort.

Positioning

The patient may be supine or in a seated position. The arm should be carefully placed in the position of function, with the wrist slightly extended, the metacarpophalangeal joints flexed toward 90 degrees, and the arm in neutral supination, as shown in the image below.

The wrist should be splinted in neutral position, rather than the extension present in many prefabricated splints.^[8]

Monitoring & Follow-up

Once the splint is applied and fully hardened, an elastic wrap is often used to hold the splint and to protect it. It is once again important to observe and document the neurovascular status of involved arm. Any changes in the neurovascular status compared with the presplinting examination should be considered the result of splint application (or fracture reduction). Effort should be made to reverse that change, including removal of the splint.

The patient should be asked about their comfort level in the splint. Any discomfort felt immediately after splinting could indicate improper splint application and increase the risk for complications. Timely follow-up is encouraged to avoid excessive time in the splint and to receive prompt care for the injury. For the majority of conditions, follow-up should be done within 2 weeks of splinting.

General Splinting

Once the steps of preparation are complete, the splint may be applied. Each type of splint is applied somewhat differently, but there are basic steps that are common to all splints.

A stockinette should be placed over any part of the arm to which the splint will be applied. This stockinette should be cut long on each end so that it extends past the splinted area. See the image below.

After the stockinette, several layers of cotton cast padding are applied, paying close attention to area of bony prominence, such as the ulnar head and knuckles. For simple splints, the layers of padding and splint material may be applied together. Commercial preparations consisting of fiberglass surrounded by padding material are also available. See the image below.

In the case of splint application to maintain fracture reduction, a 3-point mold technique is used. This involves applying pressure at the fracture site on one side, while simultaneously applying pressure above (proximal) and below (distal) on the opposite side.

The mold technique is performed while the splint is hardening. Fingertraps should be used during the mold to avoid focal points of pressure on the skin. Fractures that have been reduced have a tendency to fall back into their original angulation, and application of a splint in this manner can help to maintain the reduction. The pressure at these locations should be maintained until the splinting material is fully hardened.

Ulnar Gutter Splint

This splint is applied to the ulnar aspect of the arm. Its proximal extent depends somewhat on the location of injury, but should extend at least above (proximal) the midshaft ulna. Distally, the splint extends over the metacarpophalangeal joints at least to the proximal interphalangeal joints, and possibly past the distal interphalangeal joints, depending on the location of injury.

This splint covers the fourth and fifth digits both volarly and dorsally. For injuries to the fourth digit or metacarpal, the third digit should be included as well. As previously mentioned, the arm should be placed in its position of function prior to splinting. Cast padding should be placed between the involved digits to avoid skin maceration. See the image below.

Radial Gutter Splint

This splint is similar in function to the ulnar gutter splint, except it is used for injuries to the second or third rays. It is applied in a similar manner as the ulnar gutter splint but on the radial aspect of the arm. The thumb is left free and the second and third digits are splinted as described in the ulnar gutter splint. See the image below.

Thumb Spica Splint

This splint is applied the radial aspect of the distal forearm. It extends proximally to the radial midshaft or higher. Distally it encircles the thumb and extends to the interphalangeal joint of the thumb or past, as needed. The thumb may be slightly flexed at the joints. See the image below.

Volar/Dorsal Slab Splints

Volar/dorsal slab splints are applied to the volar (anterior) and dorsal (posterior) aspects of the arm, respectively. Their proximal and distal extent depends on the location of injury. A typical use for a volar splint after carpal tunnel surgery would have the splint extend proximally to mid-arm and distally to mid-palm. See the images below.

Sugar Tong Splint

The sugar tong splint is a long slab of either plaster or fiberglass folded into a U-shape. The splint goes down the dorsal aspect of the arm, loops around the distal humerus region with the elbow bent at approximately 90 degrees, and goes back up the volar aspect of the arm. This splint is designed to limit pronation and supination. See the image below.