Chapter 29. Hand Trauma

Hand injuries are one of the more common reasons for emergency department visits. Hand injuries may be isolated or part of multiple trauma. These injuries are seldom life-threatening but can result in significant disability, threatening a patient's livelihood and lifestyle. These injuries can have significant economic impact with possible loss of occupation and lost time from work. Systematic examination and initial care has a direct effect on the ultimate consequence of any hand injury. Overall, it is far better to under treat and refer than to over treat and cause avoidable iatrogenic injury or disability. The course of recovery depends on initial management.

Position the Patient

A hand-injured patient may be examined while they are sitting but the environment should be calm and controlled. That does not apply to a patient with hand lacerations. It is best to examine the injured patient with a hand laceration while supine. The hand should be extended on a hand table next to the bed. The area should be clean, sterile, and have excellent lighting and all essential instruments available. It is best to have an assistant if possible for helping with lighting, positioning, and repair. There is a tendency in EM to see hand patients in hallways, chairs, and less than ideal circumstances. This must be avoided at all costs.

Control Bleeding

Bleeding is controlled by direct pressure with sterile gauze packs, elevation, and, if necessary, an arterial tourniquet (eg, blood pressure cuff inflated above systolic blood pressure). Do not use clamps unless all other measures fail. Blind clamping of vessels can lead to further injury.

Obtain History

Current Injuries

Ascertain the mechanism of injury by questioning the patient or others. An exact description of how the injury occurred will help determine the need for X-ray, antibiotics, urgent consultation in the ED, or in a follow-up visit. It is important to document the mechanism of injury, the time at which it occurred, and the environment in which it occurred. Ask about the following details associated with the mechanism of injury:

• Type of injury—crush, exploding, or simple amputation.
• Lacerations—exactly what device was involved and how the lacerations were caused.
• Position of the hand at the time of the injury (ie, fingers extended or flexed).
• Presence of pain, numbness, paresthesias, weakness, discoloration, coldness, clumsiness or poor coordination, or crepitus.
• Circumstances surrounding open wounds—environment, whether inflicted in a dirty environment (ie, sewer or barnyard) or in a specific situation (ie, fight-clenched fist).

Relevant History

• History of prior or existing hand or upper extremity injuries or disorders. Dupuytren's fasciitis, arthritis, and benign tumors are the most common nontraumatic problems noted.
• Bleeding disorders likely to influence hemostasis (eg, hemophilia).
• Factors that might impair wound healing (eg, use of corticosteroids).
• Tetanus immunization status (Chapter 30).
• Any allergies.
• General state of health, medications, and ongoing treatments.

Examine the Hand

Examination of the hand is started while the history is being taken. In the event of an open wound, proper instruments and sutures must be made ready. Sterile technique is essential at all stages of the examination and early treatment of hand injuries. A sensory examination for two-point discrimination should be done with an opened paper clip before anesthesia is used. Before beginning active examination, anesthetize the injured area of the hand, and apply and inflate a tourniquet. Be certain to remove rings from the patient's hands prior to any examination, radiographs, or procedures.

Anesthesia

Anesthesia must be used if a wound is to be explored or sutured. The preferred anesthetic is 1% lidocaine without epinephrine. It is recommended that epinephrine never be used with local anesthetics in hand injury, because it may constrict the vessels and interfere with blood flow. See Chapter 30, Wound Care for further discussion of specific techniques.

Digital Block or Wrist Block

(See Figures 29–1, 29–2, 29–3.) Digital blocks are preferred for procedures done distal to the PIP joint. Half-inch (1.5-cm) needles of 25, 27, or 30 gauge should be used with small volumes of 1% lidocaine, or 0.5% bupivacaine may be used as a mix for a longer-acting anesthetic. In a digital block, use about 0.5–1.0 mL anesthetic around the digital nerve. The injection should never render the tissues tense nor be circumferential.

In blocking peripheral nerves, the physician must be familiar with the anatomy of nerve distribution and the surrounding tissues. To avoid intravascular injection, always aspirate before injecting the anesthetic agent.

Transthecal Digital Block

This block is preferred for injured digits, particularly the distal phalanx, nail bed, and volar tip. But should not be performed if there is an infection or suspicion of a flexor tenosynovitis. The digit to be blocked is extended and comfortably placed on the examination table. A 5-cc syringe with 27-gauge needle is preferred. The block should be performed with a 50:50 mixture of 1% lidocaine: 0.5% bupivacaine (see Figures 29–4). Identify the midpoint of the MCP flexion crease, insert at 90° until striking bone, then angle the tip of the needle 45° distally. Inject 2–3 cc into the flexor tendon sheath. With the tips of the opposite index and long finger palpate the infusion of medication into the sheath. In addition, the digit will gradually assume a partially flexed position. These blocks only require one needle stick. They are safe and effective. Complications are rare.

Local Infiltration

(See Chapter 30, Figure 30–1.) Wounds can be infiltrated locally as long as the amount of anesthetic injected does not make the tissues tense.

Amount of Solution

Systemic toxicity from over dosage may occur when large areas are anesthetized. This can be avoided by calculating the number of milligrams of drug in the volume of solution that may be required and then limiting the volume of injection so as to avoid giving a toxic dose (see Table 30–1). For example, the maximum adult dose of 1% lidocaine (10 mg/mL) without epinephrine is 300 mg (or 30 cc).

Inflamed Areas

Anesthetic solutions should not be injected into inflamed areas unless these directly overlie an abscess that is to be drained. Such injections impair local tissue resistance to infection, may result in rapid systemic absorption because of the increased vascularity of inflamed tissues, and may be ineffective if the local tissue pH is low enough to reduce the anesthetic agent's ionic dissociation, which is essential for anesthetic activity.

Application of Tourniquet

An arm tourniquet should be in place when bleeding hand wounds are examined or treated. A blood pressure cuff can be used but should be inverted so that the tubes extend cephalad and out of the way. First, wrap the patient's arm with cast padding, then place the cuff and inflate to 200–250 mmHg before locking (or Kelley clamps placed). This method should sufficiently occlude the brachial artery and reduce further hemorrhage. Be aware, a properly placed tourniquet will become quite painful to the patient within a few minutes and should be used only as necessary to prevent uncontrolled blood loss or allow essential evaluation of the wound.

Examination Sequence

By dividing the examination into four distinct steps, much useful information can be gained rapidly.

1. Observe the posture of the hand lying supine and at rest upon the examining table. Any marked variation from the normal attitude should alert the examiner to the possibility of deforming injury.

2. Observe active function of the various musculotendinous units and skeletal structures within the areas of injury. A careful examination of the flexor digitorum profundi and flexor digitorum superficialis must be performed.

3. Assess loss of sensibility by testing for sweat and for awareness of pain. Two-point discrimination is a sensitive, objective measure of sensory deficit. This may be difficult to be performed accurately, and the character and location of a wound may be more helpful than sensory nerve testing in determining nerve injury. Sensory testing must be performed before application of a tourniquet and administration of anesthetics.

4. Inspect the wound in a sterile, bloodless field with a simple 2.5-power magnifying loupes, if available. A tourniquet should be in place but should not be inflated until the anesthetic has become effective unless there is uncontrollable hemorrhage (see above). The examination must proceed concurrently with early treatment such as cleansing and debridement (Chapter 30) before definitive emergency treatment and suturing are done. Note: In handling and examining tissue, remember the importance of removal of blood clots and careful manipulation of tissues to preserve the microcirculation.

1This chapter is a revision of the chapter by Adam Saperston, MD, MS, from the 5th edition.

(See Figures 29–5 and 29–6.) The hand is a highly mobile organ of extraordinary sensibility and remarkable adaptability, but it can be troubling if injured, causing permanent stiffness, pain, or loss of sensibility. Prevention is key and a sound knowledge of functional hand anatomy helps diagnosis and treatment of these wounds.

Terminology

(See Figures 29–7.) The hand and each finger have ulnar and radial sides and palmar and dorsal surfaces. There are five digits numbered and named as follows: I (thumb), II (index), III (long or middle), IV (ring), and V (small [little]). Commonly used abbreviations for the joints of the hand are shown in the box at the beginning of the chapter. Always specify which hand is injured, and note whether it is the dominant or nondominant hand.

Skin and Circulation

The skin of the palm sweats freely and is thick, tough, tethered by fascia, highly innervated, and well cushioned by fat. The dorsal skin, by contrast, is thin, very mobile, and less well supplied with sensory nerves. The arterial supply is mainly palmar. Venous and lymphatic drainage is mainly dorsal and can be impeded by dorsal injury, constriction, or taut skin.

Twelve Extrinsic Flexors

See Figures 29–5.

Anatomy

Wrist Flexors

There are three wrist flexors: the flexor carpi ulnaris (innervated by the ulnar nerve), the palmaris longus (median nerve), and the flexor carpi radialis (median nerve).

Digital Flexors

There are nine digital flexors (one for each IP joint). The flexor pollicis longus (innervated by the median nerve) flexes the thumb IP joint. Flexor digitorum superficialis (sublimis) moves each PIP joint (all median nerve). Each superficialis is generally able to contract independently, because the muscles are independent for each digit.

A flexor digitorum profundus moves each DIP joint (median nerve to index and long fingers; ulnar nerve to ring and small fingers). The three ulnar profundi have a common muscle mass, and therefore one cannot contract and move one of these digit tips independently.

Testing of Flexors

Flexor Carpi Radialis

The flexor carpi radialis is tested by having the patient flex the wrist; it can be palpated on the radial aspect of the wrist. The flexor carpi ulnaris is also palpable when flexed. The palmaris longus is palpated by partially flexing the palm and touching the thumb and fifth digit to one another.

Superficialis Flexors

The superficialis flexors are tested by holding three digits not being tested in full extension and directing the patient to flex the fourth one. PIP flexion indicates an intact superficialis to that finger.

Profundus Flexors

The profundus flexors are tested by asking the patient flex the distal tip of the examined digit while immobilizing the rest of the digit at the PIP joint.

Flexor Pollicis Longus

The flexor pollicis longus is tested by having the patient actively flex the terminal phalanx of the thumb.

The flexors should be tested actively and with opposition. A partial flexor tendon laceration is best identified through opposition testing.

Twelve Extrinsic Extensors

(See Figures 29–6.) All extensors are innervated by the radial nerve.

Anatomy

Central Wrist Extensors

The extensor carpi radialis longus and extensor carpi radialis brevis insert into the bases of the second and third metacarpals, respectively.

Extensor and Ulnar Deviator

The extensor carpi ulnaris inserts into the base of the fifth metacarpal.

Abductor Pollicis Longus

The abductor pollicis longus deviates the wrist radially and stabilizes the base of the thumb (first metacarpal). It is tested by abducting the thumb radially.

Two Thumb Extensors

The extensor pollicis brevis acts mainly at the MP joint; the extensor pollicis longus acts at the IP joint in concert with the intrinsics but, unlike the intrinsics, can extend the joint with much force and can even hyperextend it.

Four Finger Extensors

An extensor digitorum communis to each finger forms the central slip (MET) of the extensor hood.

Index and Small Fingers

The index and small fingers have independent (proprius) extensor tendons as well. These extend these fingers when the long and ring fingers are flexed.

Testing of Extensors

Test the extensors by asking the patient to extend the fingers at the MP joint and to extend the IP joints. The latter is achieved by action of the extensor in conjunction with the intrinsic tendons in the extensor hood. The proprius tendons of the index and small fingers always lie ulnar to the extensor digitorum communis of each.

Twenty Intrinsic Muscles

Anatomy

Of 20 intrinsics, 15 are innervated by the ulnar nerve and five by the median nerve. In conjunction with the extensor tendon, they form the extensor hood mechanism, which is a proximally based triangular sheet of three interconnected tendons. The lateral margins (“lateral bands”) are the small LETs from the intrinsic muscles. The central large tendon (“central slip”) from the extrinsic extensors is called the MET, which inserts on the middle phalanx of each finger. The TET is made up of a coalescence of METs and LETs into a very thin tendon that inserts on the distal phalanx. In the case of the thumb, which has only two phalanges, the equivalent of the MET is the extensor pollicis brevis; the equivalent of the TET is the extensor pollicis longus. The intrinsics flex the MP and extend the IP joints and abduct and adduct the digits. Working all together, they cup the palm.

Testing of Intrinsics

Thenar and Hypothenar Intrinsics

The thenar and hypothenar intrinsics act to pronate the thumb and little finger and thereby cup the palm. Have the patient make the distal fat pads of the thumb and small finger meet.

Other Intrinsics

Have the patient abduct the extended second through fifth digits; then flex these digits at the MP joints while extending the PIP and DIP joints.

Examination of Nerve Injuries

The three major nerves to the hand are the radial, median, and ulnar nerves.

Radial Nerve

The radial nerve innervates all extensors.

Motor Testing

Muscle testing is done by having the patient extend the wrist and digits (Figures 29–8C). This is best performed against opposition.

Sensory Examination

The radial nerve gives off a sensory branch that provides sensibility for the dorsal–radial aspect of the hand (Figures 29–8A and B).

Median Nerve

The median nerve innervates 9 of 12 extrinsic flexors, the lumbricals to the index and long fingers, and the three muscles of the thenar eminence, which are mainly concerned with opposition.

Motor Testing

High Median Nerve

Testing for high median nerve injuries is done by flexing the DIP joint of the index finger and the IP joint of the thumb (Figures 29–9).

Have the patient passively hold the fourth and fifth fingers fully flexed into the palm and follow this by full active flexion of the second and third fingers (Figures 29–9C).

Have the patient flex the thumb to touch the distal palm at the base of the fifth finger (Figures 29–9D).

Low Median Nerve

To test for low median nerve loss (eg, at the wrist), have the patient pronate the thumb, pressing the distal fat pad of the thumb against that of the ring finger. Then feel for a firm, contracted adductor pollicis brevis alongside the thumb meta-carpal.

Sensory Examination

The median nerve provides sensibility to the radial two-thirds of the palm and the palmar surfaces of the thumb, the index, and long fingers, the radial side of the ring finger, and the dorsal surface of the middle and distal phalanges of these fingers (Figures 29–9A and B). Because of the importance of this zone of sensibility, the median nerve is called the “eye of the hand.”

Ulnar Nerve

The ulnar nerve innervates 15 of the 20 intrinsic muscles and only three extrinsic muscles.

Motor Testing

The intrinsics are tested by any of the following maneuvers: With the palm flat on the table, have the patient abduct and adduct the fingers, cross the fingers, or forcefully move the pointed index finger in a radial direction.

The extrinsics are tested as follows: Forcefully flex the tips of the ring and small fingers to meet the distal palm to evaluate their profundi (Figures 29–10C); then forcefully spread the fingers apart and palpate for a tensed flexor carpi ulnaris tendon at the wrist.

Sensory Examination

The ulnar nerve innervates the radial and ulnar halves of the pads of the small finger, the ulnar half of the pads of the ring finger, and the ulnar side of the hand (Figures 29–10A and B). The additional loss of sensibility on the dorsoulnar aspect of the body of the hand signifies a high lesion well proximal to the wrist.

Radiographic Examination

Severe injuries to the hand require imaging to detect fractures, dislocation, and opaque foreign material or gas. X-ray is the standard imaging modality for the majority of hand injuries; CT or MRI should be utilized in consultation with the hand/orthopedic surgeon. Special radiographs should be requested, depending on the site and direction of trauma. For example, scaphoid bone or digit-specific films should be requested as clinically indicated to improve evaluation of isolated injuries. If there is any doubt about the normalcy of the skeleton, comparable views of the opposite side should be taken for comparison. Recent literature has also demonstrated the utility of high-resolution ultrasound (HRUS) in the evaluation of common soft-tissue diseases of the hand/wrist (eg, synovitis, tendon injury) as well as detection of foreign bodies in the tissue. There is insufficient evidence for HRUS in diagnosis of fractures. This modality may be limited by the availability of an experienced upper extremity sonographer.

Instruments, Antiseptic Solutions, and Sutures

Needles

Suturing should be carefully done with fine-pointed and very sharp cutting needles (eg, Ethicon P-1, P-3).

Suturing Material

Fine (5-0 or 6-0) monofilament polypropylene suture material is preferred for skin closure. Only in infants and children should an absorbable suture such as 5-0 or 6-0 chromic or plain catgut be used.

Instruments

Fine plastic surgery forceps, retractors, clamps, and needle holders are required.

Skin and Wound Preparation

The skin around the wound may be sterilized as described in Chapter 30. The hand and wound may be irrigated with normal saline. Avoid prolonged soaking.

Dressings, Splints, and Antibiotics

Inner Dressings

Petrolatum-impregnated gauze followed by a surgical gauze sponge saturated with water (tap water or sterile saline solution) is applied over the wound as the “core” dressing. The wetness draws blood from the wound and prevents dead space. None of this goes circumferentially around the digit, hand, or forearm.

A foam pad such as a Reston pad with an adherent surface on one side (or comparable substitute) is then applied over the core dressing. Soft elastic gauze (Kerlix, Kling) or cast padding to form a soft, well-padded dressing is applied over the foam pad and may go circumferentially around the part.

Splint

The wrist is the most important joint to splint for all major hand injuries, even if only one digit is injured. Well-padded plaster as a splint protects the hand.

For isolated pain-free dorsal injuries at the DIP or PIP joint, a tongue blade cut to the length of two phalanges and padded with gauze or foam rubber makes an excellent splint. There are ready-made aluminum splints with soft padding or other surface that are most effective. If there is a wound over the joint, such a splint should be placed on the palmar side; if not, it is placed on the dorsum. After cutting the splint be certain that sharp edges are smoothed and padded and the patient is protected.

The most useful palmar splint consists of 10–12 layers of plaster cut to fit the involved digit or digits and extending halfway up the volar surface of the forearm. It is padded with a thin foam pad (eg, Reston) and held in place with a loosely wrapped roll of plaster of paris, bias-cut stockinet, or elastic bandage. The hand generally should be in the “position of function,” that is, slight wrist extension and MP flexion, with the PIP and DIP joints in partial extension and the thumb web open (Figures 29–11). Modification must be applied to take tension off a specific wound.

Sling

No patient should leave the emergency department without a sling to hold the hand at the level of the heart or higher to promote venous and lymphatic drainage. Slings that hold the hand lower than the heart encourage the development of tissue edema. To avoid a tourniquet effect, the extremity should usually be outside of a sleeve.

Lacerations

Small Lacerations

Simple lacerations (superficial lacerations not extending into subcutaneous fat and not perpendicular to skin tension lines) can be closed by sterile surgical tapes (ie, Steri-Strips) or tissue adhesives. The hand and digits are so active that it is usually advisable to use suture material. Wounds that require sutures (lacerations that are parallel to skin tension lines or into subcutaneous fat) should be evaluated in a sterile, bloodless field. Splinting and elevation of the limb can help healing and reduce pain. Splinting is also important for wounds that cross joints to prevent joint stiffness or contracture from wound scarring. Follow-up with a primary care physician in 7–10 days for suture removal is appropriate. There are liquid adhesives that are effective for clean, straight laceration. Given the diminutive size of many hand/wrist lacerations encountered in the emergency department, it is vital to fully evaluate neurologic, tendon, and vascular functions distal to the wound. Literature suggests that significant deep structure injuries may be missed in the routine evaluation of minor hand wounds. Tendons are the most common deep structure injured in lacerations less than 3 cm, though nerve and arterial injuries are also observed.

Extensive Lacerations

Wounds should be carefully evaluated in a sterile, bloodless field. Irrigation and cleaning with tap water or sterile saline is the next step. Careful handling of tissues is essential. Approximate the wound margins with sutures. A wound should not be closed under tension. If the edges cannot be easily approximated, the wound may be left open and the patient referred to a hand surgeon for primary or delayed split-thickness grafting.

Antibiotic Therapy

Infected and grossly contaminated deep-tissue wounds (including open fractures) require extensive irrigation and may need debridement in the ER. Extensive disease should be admitted to an inpatient setting. Prompt antibiotic treatment in the ED is mandatory for infectious emergencies, along with a therapeutic course of oral antimicrobials for patients appropriate to discharge. A prophylactic course may be appropriate for less severe injuries. Although a full discussion of antibiotics for dermal lacerations is beyond the scope of this chapter, the physician should consider a short course (3–5 days) of antimicrobial coverage for typical skin pathogens. Further discussion of antibiotic therapy is included in the next sections. All penetrating injuries deserve consideration of tetanus prophylaxis.

Fingertip Injuries

Fingertip Amputations

Clinical Findings

Fingertip amputations are the most common type of amputation of the upper extremity. The location and size of the defect have to be considered. Depending on the location of the amputation, fingertip injuries can be classified into four zones. The zones have been designed to define the type of pulp damage and the existence of associated lesions of the nail bed and bone. The zone 1 lesion is a distal amputation located far from the distal phalanx tubercle. Usually the lesion is less than 1 cm in area and does not affect the nail bed or bone. Zone 2 lesions involve the nail bed and usually partial phalangeal bone disruption and exposure. In zone 3 injuries, the nail matrix is involved so that the nail growth will be followed by curved deformation. Zone 4 defines an amputation at the level of the distal phalanx, near the DIP joint. Despite the intact distal attachment of the extensor and flexor tendons at the distal phalanx, the active motion of the distal remnant is limited.

Important information to be obtained from the patient includes age, the digit injured, mechanism and time of injury, occupation, location of the wound, and hand dominance. The digit injured influences management. Most hand surgeons want to maintain the length of the thumb. The index finger is considered the next priority before other fingers. An intact pulp-to-pulp pinch mechanism is the goal.

Treatment and Disposition

For zone 1 injuries with pad loss of less than 1 cm, healing by secondary intention is the simplest and often best approach. It is the treatment of choice for pediatric fingertip amputations, especially when there is no bone exposure. Initial treatment includes wound cleansing, a nonadherent sterile dressing, appropriate tetanus prophylaxis, splinting, and a bulky dressing to protect the tip. Amputations that expose the distal phalanx are usually treated as contaminated open fractures with an initial intravenous dose of a cephalosporin followed by an oral course. Patients should have appropriate follow-up care in 1–3 days for wound care check.

Fingertip amputations that have significant pad loss or bone loss (zones 2–4) usually require the expertise of a hand surgeon. Surgical options include primary closure, full- or partial-thickness skin grafts, composite grafts, flaps, and replantation. If the amputated fingertip pad has been retained, is clean, and is in good condition, it may be reattached as a full-thickness skin graft.

Subungual Hematoma

Clinical Findings

Hematoma from blunt trauma (ie, a hammer blow) or crush injury that ruptures subungual blood vessels causes pain and dark red to black discoloration of the nail bed. An X-ray is needed to rule out a fractured phalanx.

Treatment

Large subungual hematomas cause significant pain and should be evacuated via nail trephination (making a hole in the nail) with a high-temperature microcautery device or an 18-gauge needle or via complete removal of the nail. Use of heated paper clips may introduce carbon particles known as “lampblack” into the nail bed and is discouraged. Anesthesia is not usually required for trephination, and pain relief is immediate following decompression. Large subungual hematomas are often associated with significant nail bed lacerations. Many surgeons recommend removal of the nail and repair of nail bed lacerations for large subungual hematomas to promote optimal healing and normal nail growth. When the nail is removed, it should be cleaned and placed back into position, secured with sutures to function as a splint for the nail bed and to keep the proximal nail fold open.

A fracture of the distal phalanx on radiographs may technically be called an open fracture, although these injuries usually heal without complication. Osteomyelitis is not often associated with ungual tuft fractures. The risk of infection with an open fracture of the phalanx proper should be considered, and a broad-spectrum antibiotic and close follow-up are recommended.

Disposition

Patients with a subungual hematoma may be discharged from the emergency department after treatment (trephination, nail removal with or without nail bed repair). All patients with subungual hematoma should be informed about the possibility of nail loss or deformity. Antibiotics are recommended for hematomas associated with tuft fractures.

Avulsion of Nail

Clinical Findings

Avulsion of the nail results from a force elevating the tip of the nail and ripping it off its bed or from a downward crushing force sufficient to tear the base of the nail out of the eponychial sulcus, ripping open the nail bed, and carrying the nail plate on a palmar-based pedicle flap.

Treatment

Nails avulsed at the base may need to be completely removed. If such a nail is left in place, a badly lacerated nail bed that requires repair may inadvertently be overlooked. The nail also creates a dead space that promotes scarring and infection.

Removal of Nail

Anesthetize by digital block. Remove the avulsed nail by inserting a clamp under the distal attached portion of the nail and advancing it proximally, removing the nail by spreading the clamp. The exposed nail bed should be covered with either the original nail (as described above) or with sterile petrolatum gauze and a portion of the gauze tucked into the nail sulcus. A lacerated nail bed should be meticulously closed with 5-0 or 6-0 absorbable suture.

Reattachment of Distal Torn Finger Flap

If the distal portion of the finger has been torn off with the nail and has been left attached to the finger by a volar pedicle, the flap should be anatomically reduced and sutured back in position with 6-0 absorbable suture. Antibiotics should be administered.

Management of Fractures

Open fractures of the distal phalanx are reduced and held by soft tissue suturing. If the fracture is displaced, internal fixation with a Kirschner wire may be necessary.

Disposition

The patient should follow-up in 2–3 days for wound check and dressing change. Complicated problems should be referred to a hand surgeon and an immediate appointment made.

Distal Extensor Tendon Injuries2

Laceration of Extensor Tendons

Clinical Findings

Dorsal finger and hand wounds frequently result in a partially or completely lacerated extensor tendon or extensor tendon hood mechanism. The extent of injury can be determined only by adequate exposure and direct examination. Accurate assessment of a tendon can be difficult because a 90%-lacerated tendon can still retain function. A partial tendon laceration can often be discovered by testing the tendon against resistance. Strength against resistance is diminished if a partial tendon laceration exists. In addition, the patient will usually note pain with resistance. Description using the eight zones of extensor tendon injuries will help assess and guide treatment (Figures 29–12).

Treatment

Treatment of a partial tendon laceration that is less than 50% may require no repair and be effectively treated with a protective splint. Minor extensor tendon repairs can be performed in the emergency department after careful irrigation, inspection, and debridement or later by the consultant.

If the tendon ends can be retrieved easily with minimal extension of the wound or by slight stretching of the skin, the tendon should be repaired by a simple figure of-eight suture or a crisscross suture technique with 4-0 or 5-0 suture (in infants, 6-0 nylon). This repair should ideally be performed by the hand surgeon (Figures 29–13). A padded plaster forearm splint is then applied with the digit and hand positioned so that the repair is relaxed as much as possible. No individual joint should be hyperextended, nor should all joints be simultaneously extended. The MP joint should not be immobilized in full extension, because contraction of collateral ligaments may result in fixation of the joint in extension. One or more neighboring fingers should always be immobilized with the injured digit.

Disposition

If the tendon ends are not easily retrieved, a hand surgeon should be consulted for follow-up and the patient should be seen in the next 1–2 days. In the interim, administer antibiotics for 2–3 days (see discussion of cellulitis, below).

Mallet Finger

Essentials of Diagnosis

• Suspect if bruising is present at DIP joint
• X-ray may be normal or show an avulsed chip at DIP joint
• Carefully test extension of DIP joint
• If left untreated, swan neck deformity may occur

Clinical Findings

Mallet finger is caused by laceration or avulsion of the extensor tendon at its insertion at the dorsum of the distal phalanx. A mallet finger commonly occurs after the distal finger is forcibly flexed, such as from a sudden blow to the tip of the extended finger. Clinically, there may be ecchymosis at the DIP joint, but tenderness and swelling may be less than anticipated. An X-ray may be normal or demonstrate an avulsed chip fragment at the dorsum of the DIP joint. If the articular fracture involves more than 40% of the joint surface, referral to a hand specialist for open reduction is required. The extensor lag may not be present on the initial emergency department evaluation. Careful testing of extension at the DIP is important in identifying this problem. In many cases the patient is too uncomfortable to perform a good examination. If left untreated, a flexion deformity at the DIP joint will develop followed by hyperextension at the PIP joint (swan neck deformity) (Figures 29–14).

Treatment

Open Mallet Injuries

Open injures are treated by tenorrhaphy and intramedullary fixation of the DIP joint by a hand surgeon. Give prophylactic antibiotics (see discussion of cellulitis, below).

Closed Mallet Injuries

Closed injuries may be treated by continuous dorsal external padded splint fixation of the DIP joint in full extension for 6–8 weeks. During splint changes, the joint should be held up in extension. Notify patients that any flexion at the DIP joint during the healing period will negate the healing that has already occurred and require another 6–8 weeks of treatment. The digit should be kept dry to prevent maceration of the skin.

Disposition

These cases can have a poor outcome in the best of hands; therefore, have the patient follow-up with a hand surgeon.

Boutonniere Deformity

Essentials of Diagnosis

• Suspect when trauma causes a painful, swollen PIP joint
• X-rays are usually normal
• Deformity is rarely clinically identifiable immediately after the event

Clinical Findings

Early diagnosis of a closed MET (middle phalanx extensor tendon) rupture or avulsion is difficult before the boutonniere (buttonhole) deformity has occurred. High suspicion is needed when the patient presents with trauma and a painful, swollen PIP joint. Although uncommon, volar dislocations of the PIP joint can cause MET rupture. Unless a dislocation is present, radiographs are usually normal.

In boutonniere deformity, the distal joint is hyperextended and the PIP joint of the finger (the MP joint of the thumb) is flexed (Figures 29–15). Extensor hood integrity is lost at the apex of the PIP joint of the finger (MP joint of the thumb) as a result of laceration or blunt trauma to the dorsum of the joint. The deformity rarely manifests immediately after trauma and comes on insidiously as a result of gradual stretching of the injured hood. The underlying head of the bone protrudes through the hood, pushing aside the MET (extensor pollicis brevis of the thumb), which recedes, and the LETs (lateral extensor tendons) slip volarly to become flexors of the joint and hyperextensors of the distal joint.

Treatment

Open Injuries

Open injuries should be repaired (by a hand surgeon) as soon as possible with figure-of-eight nylon sutures and the joint splinted in full extension for 4 weeks with a palmar digital splint.

Closed Injuries

Closed injuries must be suspected if there is a history of a direct blow to the dorsum of the joint followed by swelling. Treatment consists of 4 weeks of PIP (thumb MP) splinting in extension to avoid boutonniere deformity, which rarely occurs if prompt treatment is provided.

Secondary reconstruction of this deformity is very difficult and may never restore full motion of the IP joints.

Disposition

Open injuries should be irrigated and covered and the patient evaluated by a hand surgeon at once emergently. Patients with suspected closed MET injuries should get early referral to a hand surgeon. The hand should be splinted with the PIP joint in extension, leaving the MP and DIP joints mobile.

Bone and Joint Injuries

Bone and joint injuries are discussed in more detail in Chapter 28, but a few general principles are emphasized here.

Clinical Findings

If there is any question of bone or joint injury on X-ray, obtaining added views in other planes and identical views of the opposite extremity or a follow-up view in 7–10 days may resolve the issue.

Treatment

Splinting

The wrist joint is the principal joint governing movement and comfort of an immobilized fracture. Therefore, it should be splinted initially. In addition, to splint one finger well, an adjacent finger should be splinted with it. The thumb may be immobilized alone. The preferred position should be that of wrist extension, functional finger flexion, and opposition of the thumb. The splint should be functional but applied in such a way that it can be loosened or removed if swelling or pain occurs. In addition, the splint should allow good visibility of the effected digit.

Stable Injuries

Stable dislocations or fractures can usually be treated in the emergency department by reduction and splinting, with appropriate anesthesia. Force should never be used. In lieu of force, open reduction is preferred.

Open or Unstable Injuries

Unstable closed injuries may include a dislocation that is not reducible by the EP, or one that spontaneously recurs after reduction. Open or unstable injuries require a specialist's skill. The patient should be given a temporary splint and dressing and referred to a hand surgeon for emergency follow-up care. Naturally, any structure with neurologic or vascular compromise requires prompt specialized intervention. Prophylactic antibiotics are indicated for open wounds.

Disposition

Patients with closed, stable injuries should follow-up with an orthopedic surgeon or hand specialist in 2–3 days for assessment of comfort and integrity of the splint. Patients with open joint injuries, unstable injuries, or injuries that cannot be reduced easily must be referred early to a specialist experienced in hand surgery.

Infections

Infections of the hand are frequently encountered in emergency departments. Nearly all infections result from neglect following trauma and are fostered by venous congestion and tissue edema.

Careful handling of tissue, elimination of dead space, immobilization and elevation of the arm immediately after injury, and avoidance of constriction by snug clothing or jewelry are far more important in preventing infection than any type of wound preparation or antibiotic prophylaxis. The objective of treatment of all infections is to reverse congestion and restore normal circulation. If there is a possibility of serious infection, immobilize the hand in a splint. Applying zinc oxide ointment next to the skin in the inner (core) dressing promotes drainage by preventing drying, caking, and sealing off of the wound.

All existing or potential infections should be monitored closely, for example, hourly or daily depending on the severity. Infections that may be treated in the emergency department include those of the nail folds, felons, simple abscesses, and cellulitis. Patients with other infections should be immediately referred.

Paronychia and Eponychia

Essentials of Diagnosis

• Swelling and collection of pus inside or around nail fold
• Consider X-ray to rule out foreign body or osteomyelitis
• Consider antibiotics if extensive cellulitis or lymphangitis is present

Clinical Findings

Inflammation leading to a collection of pus inside the nail fold is seen after trauma (Figures 29–16A). If neglected, it may extend around the entire nail margin and cause a floating nail. The usual cause is Staphylococcus aureus. Cultures are rarely necessary. Chronic paronychia is found in patients with occupational exposure to moisture or cleaning solutions (ie, housekeepers or dishwashers) and is most often caused by Candida albicans.

An X-ray should be considered to rule out the presence of a foreign body or distal phalangeal osteomyelitis.

Treatment

Treatment consists of simple incision, drainage, and elevation of the nail fold with a No. 11 scalpel at the site of maximum tenderness or pus (Figures 29–16B). Generally, there is no pain if an abscess is already pointing and no blood is drawn with the scalpel. If the scalpel causes any pain, administer a digital block anesthetic.

Antimicrobial agents are not indicated unless extensive cellulitis or lymphangitis is present. Chronic paronychia treatment may require nail removal, marsupialization of the eponychial fold, oral antibiotic, and topical antifungal ointment.

Disposition

As with any hand infection, the patient should keep the hand elevated and follow up in 24–48 hours. A common complication is osteomyelitis of the distal phalanx. Chronic paronychia requires referral to a hand surgeon for possible marsupialization.

Herpetic Whitlow

Essentials of Diagnosis

• Collection of grouped vesicles with erythematous base on the fingertip
• Use of oral acyclovir in immunocompromised individuals

Herpetic whitlow is the most common viral infection of the hand, a self-limited herpes simplex viral infection of the distal finger. It classically presents as grouped vesicles with an erythematous base on the fingertip. Treatment is supportive; oral acyclovir is used in immunocompromised patients. These infections may be overlooked if not considered in the differential. Incision and drainage of herpetic bullae is contraindicated.

Felon

Essentials of Diagnosis

• Patient has a painful and swollen distal phalanx fat pad
• Staphylococcus aureus is the most common cause
• Most felons can be drained where the abscess points—usually mid pad—with a central longitudinal incision

Clinical Findings

A felon is an abscess of the distal phalanx fat pad. S. aureus is the most common pathogen. The patient usually presents with a painful and swollen distal pulp space.

Treatment and Disposition

Classic treatment of felons emphasized the need for early and complete incision through the septa via fishmouth incisions to provide adequate drainage and to relieve pressure (Figures 29–17). But complications include damage to nerves and blood vessels as well as unstable finger pads, and painful neuromas or anesthetic fingertips may result. Most felons can be drained where they point—usually in the mid pad—by a central longitudinal incision that does not cross the distal flexion crease. Felons can also be drained by a single lateral incision. The incision should be made along the ulnar aspect of digits II–IV and the radial aspects of digits I and V, avoiding pincher surfaces. The incision is started 0.5 cm distal to the DIP joint crease and dorsal to the neurovascular bundle of the fingertip. If the incision will be extensive, the digit must be anesthetized. These can be quite painful. Irrigate and loosely pack the wound, and then immobilize the finger. Treat empirically with antistaphylococcal oral antibiotics for 5 days and arrange follow-up in 1–3 days for wound care check.

Deep Fascial Space Infections

Essentials of Diagnosis

• All deep space abscesses require referral to a hand surgeon
• Antibiotics should be started in the emergency department

The four potential deep fascial space infections of the hand are the subfascial web space, the dorsal subaponeurotic space (collar button abscess), a midpalmar space abscess, and the thenar space. Deep space abscesses are frequently seeded with S. aureus, streptococci, and coliforms. All deep space infections require referral to a hand surgeon for operative exploration and drainage. Antibiotics should be initiated in the emergency department.

Cellulitis (Including Human and Animal Bites)

Essentials of Diagnosis

• A progressive cellulitis caused by Pasteurella multocida is easily seen in the first 24 hours
• Cellulitis due to other pathogens usually takes 2–3 days to become clinically evident
• Another pathogen, Capnocytophaga canimorsus, associated with animal bites, can cause overwhelming sepsis in immunocompromised individuals
• Have a high suspicion for closed-fist bite wound when caring for patient with open wound over the MP joint following an altercation. Patients with these seemingly small wounds often present later with significant infections.

Treatment

Uncomplicated Cellulitis and Antibiotic Prophylaxis

Wounds with an increased risk of infection (ie, human or animal bites, crush wounds, or contaminated wounds) should have antibiotic coverage for S. aureus or Streptococcus pyogenes. Treatment recommendations include a first-generation cephalosporin such as cephalexin for oral use or cefazolin for intravenous use, or a penicillinase-resistant penicillin such as dicloxacillin for oral use or nafcillin or oxacillin for intravenous use. Trimethoprim–sulfamethoxazole (TMP–SMZ) or erythromycin may be effective in penicillin-allergic patients. Special consideration for polymicrobial coverage and possible admission are needed for diabetic patients and drug abusers.

Animal Bites

Infections caused by animal bites (ie, dog or cat) are often caused by P. multocida, which causes a rapidly progressive cellulitis, easily identifiable in 24 hours. Infections from other pathogens are not usually evident for 2–3 days. Another common pathogen, C. canimorsus (formerly known as DF-2), is a fastidious gram-negative rod that can cause overwhelming sepsis in immunocompromised individuals. Treatment for animal bites includes amoxicillin–clavulanate, clindamycin plus a fluoroquinolone in penicillin-allergic adults, or clindamycin plus TMP–SMZ in children. Do not close these wounds.

Human Bites

A wound over the MCP joint (especially of the dominant hand) is likely to represent a closed-fist bite wound sustained during an altercation. These wounds have a high likelihood for infection. Patients often present with infected “fight-bite” wounds several days after suffering a seemingly minor injury during a fight. Perform a thorough examination of these wounds, looking for injuries to the extensor tendon or joint capsule. Any violation of these structures mandates orthopedic consultation. Wounds that do not involve the joint capsule or the extensor tendon should be thoroughly irrigated and any devitalized tissue debrided.

The safest course of action is admission at the time of initial evaluation even without any signs of infection or tendon or joint involvement, though some support outpatient therapy with oral antibiotics and close follow-up. Infections from human bites may be those involving mixed anaerobes, streptococci, S. aureus, and Eikenella corrodens and should be treated in the hospital. Antibiotic treatment options include amoxicillin–sulbactam, cefoxitin, and ticarcillin–clavulanate. Penicillin-allergic patients may receive clindamycin plus TMP–SMZ or clindamycin plus fluoroquinolone. Prophylactic antibiotics for human bite wounds include amoxicillin–clavulanate or a second-generation cephalosporin. Given the propensity of these wounds to become infected, fight bites should never be sutured.

Disposition

Hospitalization under the care of a hand specialist is required for severe cases (extensive cellulitis, involvement of tendons or joints, infections of the palmar space, systemic symptoms, or unusual pathogens) or if the patient is unreliable or unable to take oral antibiotics. Patients with cellulitis managed as outpatients should be seen every day and hospitalized if the process continues.

Suppurative Tenosynovitis

Essentials of Diagnosis

• Swelling, erythema, and tenderness along the tendon sheath
• Exquisite pain on passive movement of tendon
• Consider gonococcal infection in young adults without an open wound

Clinical Findings

Suppurative tenosynovitis (nongonococcal) is characterized by swelling, erythema, and tenderness along the tendon sheath and, most important, exquisite pain on passive movement of the flexor tendon in the digit or the extensor tendon crossing the wrist. In flexor tenosynovitis, passive movement is achieved by holding the fingernail alone and prying it dorsally to extend the distal joint. The infection may have occurred because of an open wound contiguous to the involved tendon.

Treatment and Disposition

Whenever there is inflammation with significant swelling, immediate hospitalization under the care of a hand specialist is required for open surgical drainage and parenteral antibiotic therapy. After obtaining appropriate specimens for culture, begin a cephalosporin (eg, cefazolin, 100 mg/kg/d in three divided doses) intravenously without waiting for the results of cultures. Immobilize the wrist and hand in a splint, and support the arm in a sling until operation can be performed.

Disseminated (Hematogenous) Gonococcal Infection

The diagnosis and treatment of gonococcal infection are discussed in Chapter 42. In young adults, tenosynovitis may be caused by gonococcal infection. The tenosynovitis is not associated with an open wound near the involved tendon sheath but is frequently associated with pustular skin lesions typical of gonococcal infection. Hospitalization for intravenous antibiotic therapy is usually indicated. In selected reliable patients whose diagnosis is confirmed, outpatient therapy with close follow-up may be possible. See Chapter 42 for recommended treatment.

Minor Constrictive Problems

Clinical Findings

The three common constrictive problems described here are often seen in the emergency department.

Carpal Tunnel Syndrome (Compression of the Median Nerve)

Carpal tunnel syndrome is characterized by aching and numbness over the distribution of the median nerve (see Figures 29–9), with sparing of the small finger. These symptoms often awaken the patient from sleep and may be elicited by full flexion of the wrist for 30 seconds (Phalen maneuver). Tapping over the median nerve at the wrist crease may feel like an electric shock (Tinel sign). Though unusual, patients with this nerve compression may present with rapid onset of acute edema and progressive loss of feeling after trauma, inflammation, or allergy, and it requires urgent consultation with a hand specialist.

Stenosing Flexor Tenosynovitis (Trigger Thumb or Trigger Finger)

Stenosing flexor tenosynovitis is characterized by local tenderness over the proximal tendon pulley at the MP joint, with pain referred to the PIP joint and a snapping when the finger or thumb goes through an active range of motion. Usually a history of repetitive strain is involved.

De Quervain's Tenosynovitis

De Quervain's tenosynovitis is characterized by pain and tenderness when tendons in the first dorsal compartment on the radial side of the wrist are actively or passively stretched; specifically, when the fist is clenched over the thumb while the wrist is put into marked ulnar deviation (Finkelstein's test).

Treatment

Carpal Tunnel Syndrome

Initial treatment involves wrist splinting and the use of nonsteroidal anti-inflammatory drugs. Activity modification and therapeutic exercises may also improve symptoms. The next step in treatment is injection of the carpal canal using 1 mL of steroid and 2–3 mL of lidocaine. Oral steroids may also be of benefit; however, these treatments should not be offered in the ED setting. Patients with symptoms suggestive of Carpal Tunnel Syndrome require specialized follow-up, possible nerve conduction studies, and discussion of potential surgical options.

Flexor Tenosynovitis

Administration of nonsteroidal anti-inflammatory agents may be started in lieu of injection therapy. Steroids should not be injected if an infectious process is suspected. About 0.5 mL each of steroid and lidocaine should be injected into the synovial bursa through the tendon flexor pulley at the base of the digit. The finger should be splinted in extension.

De Quervain's Tenosynovitis

Nonsurgical treatment involves rest, splinting with a thumb spica splint, anti-inflammatory medications, stretching exercises, and corticosteroid injections. If injecting, use about 0.5 mL each of steroid and lidocaine at the radial styloid process but avoid the radial nerve. Steroid injections are not benign events and unless the EP is well trained and experienced, these procedures are best performed by a hand surgeon.

Disposition

Referral to a hand surgeon is advised because multiple injections or surgical release of the tight ligament or sheath may be required.

Thermal Injuries

See also Chapter 45.

First-Degree Burns

Clinical Findings and Treatment

Simple burns (redness without blistering) are treated with cold tap water rinse and analgesia. Comfort may be augmented by a soft nonirritating wrap to protect and immobilize the hand. Elevation and avoidance of constriction by snug garments are also advised.

Disposition

The patient should return or telephone for follow-up after 1–2 days.

Second-Degree Burns

Clinical Findings and Treatment

Blisters signify partial-thickness (second-degree) burns, which always retain cutaneous sensation even though they are variable in depth. Although this treatment is controversial, large blisters should be aspirated or un-roofed and debrided. Small blisters may be left intact. Silver sulfadiazine (Silvadene) cream may be applied topically. For sulfa-allergic patients, bacitracin or neomycin may be used instead. Second-degree burns may be dressed with a bulky dressing and the hand splinted in the position of function. Tetanus prophylaxis must be current (Chapter 30). In the case of burns caused by hot tar, the tar may be removed as described in Chapter 45.

Disposition

Patients with extensive burns or marked edema should be emergently referred to a hand specialist for evaluation and possible hospitalization. Patients with lesser involvement should be seen every 1–3 days for a dressing change, especially once blister debridement is started. Keep in mind that the thinner skin of a child's hand can more easily progress to second or third-degree injury, even in minor burns.

Third-Degree Burns

Clinical Findings and Treatment

Full-thickness (third-degree) burns require bulky, loose, sterile dressings with an anti-infective agent such as silver sulfadiazine. Appropriate elevation and splinting are also advised. Tetanus prophylaxis must be current (Chapter 30).

Disposition

If the burn is extensive (eg, >1–2 cm2 [⅜–¾ in2]) or is over the dorsum of a joint, refer the patient emergently to a hand specialist for decisions about the need for debridement and grafting.

Electrical Burns

(See also Chapter 46.) Burns from electricity are of two kinds: crossed circuit, producing arc heat; and conduction of high-voltage current within the tissues. Arc heat is often more frightening than extensively injurious to tissues. There is generally blackening of the skin owing to deposit of carbon. The burn may be anywhere from first-degree to third-degree in severity but is usually localized. The treatment of arc heat burns is the same as that of other thermal burns.

High-voltage conduction burns involve a point of entry and another point of exit. The deep tissues are often coagulated out of proportion to surface skin changes. Blood vessels and nerves are the pathways of conduction and therefore are most vulnerable. Immediate irreversible ischemia and paralysis are common. Such cases require hospitalization under the care of a hand specialist for urgent fasciotomy, where prophylactically indicated, and for observation for systemic effects of the electrical shock. Appropriate debridement (even amputation), grafting, and reconstruction will follow. Extremity destruction is sometimes overwhelming.

If the electrical conduction pathway within the body is not limited to the hand but also involves other areas, consideration should be given to possible myocardial injury. An electrocardiogram and cardiac isoenzymes (CK-MB and troponin) measurement should be obtained. Cardiac monitoring is necessary if myocardial injury is suspected.

Frostbite

(See also Chapter 46.) Exposure to cold may result in superficial or deep frostbite depending on the windchill factor and duration of exposure. Measures to prevent this vasoconstrictive disorder and the irreversible microvascular thrombotic events that lead to gangrene include the following: (1) avoiding exposure to wind, cold metal, snow, and ice by wearing protective gloves; (2) preserving the total body heat by wearing suitable clothing and head gear and avoiding sweat-producing physical effort or alcohol consumption; (3) ensuring adequate caloric intake, high in fat and carbohydrate; and (4) refraining from smoking.

Superficial frostbite is limited to the skin. It exists when the discomfort of fingers exposed to cold is replaced by numbness. Reversal by warming is urgently required and is usually heralded by a warm tingling sensation. Deep frostbite is signaled by pain and swelling of the entire hand, followed by extensive blister formation and dysesthesia. Deep frostbite requires hospitalization under the care of a hand specialist. Cryofibrinogenemia aggravates the problem and is worsened by the use of heparin, which facilitates precipitation of cryofibrinogen. Treatment consists of rest and warming the patient and the hands. Immersion in water at 37–40°C (98.6–104°F) for a short time (eg, 20 minutes) may be beneficial. Blisters must be debrided and dressed with sterile dressings. Sympathetic blockade should be considered.

Foreign Bodies

Fishhooks, splinters, and other objects may have barbs or barb-like projections that prevent withdrawal from the wound in the normal retrograde way. Removal is possible by pushing the foreign body along the direction of entry and removing it via a counterincision where it presents under the tented skin. Nerve block or other anesthesia and tourniquet ischemia are necessary before extraction is attempted. Prophylactic antibiotics and tetanus immunization are often necessary.

Foreign bodies embedded in the hand may be difficult to locate and remove. The diagnosis is based on the history and examination, and X-rays are almost always useful in the case of glass or metal. Modalities such as computed tomography, magnetic resonance imaging, and ultrasound can be helpful in finding nonradiopaque foreign bodies. If immediate accessibility and easy removal seem possible, an attempt can be made to remove the foreign body using regional anesthesia, a tourniquet, and sterile technique with loupe magnification. Typically, however, the discoloration of tissues by blood precludes the immediate search for a foreign body, which will be found much more easily after 3–4 weeks when phagocytosis has cleared the blood. Before starting the procedure, tell the patient that if search and removal prove at all difficult (eg, longer than 10–15 minutes), the procedure will be abandoned and referral made to a hand specialist.

Consider leaving an entry wound open by inserting a loose drain, applying an appropriate dressing, and elevating and immobilizing the part. Give prophylactic local or systemic antibiotics and tetanus prophylaxis (Chapter 30). The patient can usually be assured that retrieval of small deep foreign bodies is not urgent, because they do not travel in the body, and that it is often contraindicated by the difficulty and risk of removal.

Complex Hand Injuries

Classification

Complex injuries include the following: amputations, serious tendon injuries, nerve injuries, high-pressure injection injuries, closed compartment syndromes, mangling injuries, and gunshot wounds.

Evaluation and Initial Management

In complex injuries, emphasis should be placed on early, rapid diagnosis and institution of supportive therapy. Many complex injuries require referral to a hand specialist urgently. In all cases, use conservative measures as outlined below.

Avoid Manipulation

Once the decision has been made to transfer or hospitalize the patient, the extremity should not be handled, probed, manipulated, or otherwise disturbed unless absolutely necessary. Foreign material that can be easily lifted out should be removed. Protect with a sterile dressing and, if necessary, a loosely applied splint pending definitive management.

Prepare for Possible Urgent Surgery

If there is a reasonable likelihood of surgery within 8–10 hours, give nothing by mouth. An intravenous infusion should be started in the uninjured limb and laboratory work ordered.

Give Antibiotics

In the case of open or penetrating wounds, antibiotics should be given parenterally (preferably intravenously in the uninjured extremity) as soon as possible; the earlier they are started, the more effective they are. Give cefazolin, 1–2 g intramuscularly or intravenously every 6–8 hours (adult dose) or 25–100 mg/kg/d intramuscularly or intravenously, divided every 4–8 hours (for children aged >1 month).

Amputations

Clinical Findings

Amputations account for about 1% of hand injuries. The diagnosis of amputation is obvious on inspection of the part. Amputations are generally classified as partial (incompletely severed part) or complete.

Generally, tidy amputations at the level of the middle phalanx or the wrist or distal forearm have the best chance of functionally successful replantation. In the case of single-digit amputation, surgeons are much more inclined to favor replantation of a thumb than of a single finger. Discussions with the patient or relatives regarding the feasibility of replantation should be left to the hand surgeon.

Treatment and Disposition

Replantation Possible

Place the amputated member in gauze moistened with saline and then place it in a sealed plastic bag or container that is maintained at 4°C (39.2°F) (eg, on wet ice). Do not freeze the amputated part, because this destroys its viability.

After starting appropriate supportive measures, if the treating facility is not capable of providing the microsurgical specialized care required for replantation, arrange promptly for referral to a capable facility. The treating physician must contact a microsurgical specialist at the hospital to which he or she would like to refer the patient in order to obtain the specialist's permission for transfer. Failure to do so could be considered a violation of the law (COBRA-EMTLA; see Chapter 5) and might subject the referring physician and hospital to significant financial penalties.

Replantation Impossible

If the amputated member is either not recovered or is clearly not salvageable, appropriate in-house or emergency department surgery should be undertaken to close the stump. Except for the simple fingertip pad amputation (discussed above), these injuries should almost always be referred to a hand specialist.

Flexor and Proximal Extensor Tendon Injuries

Essentials of Diagnosis

• First suspect that tendon injury may exist; impairment may not become evident until hours, days, or weeks later
• Check strength of digit against resistance
• Direct visualization and examination of open wound in sterile, bloodless field is indicated

General Considerations

Almost all flexor tendon injuries, and those extensor injuries in which the proximal tendon has retracted out of reach, are considered complex injuries. Management of easily accessible extensor tendon injuries is discussed earlier in this chapter.

Clinical Findings

A crucial step in the emergency management of any flexor or proximal extensor tendon injury is to suspect that it may exist and make the proper diagnosis. Impairment of a partially divided tendon (sometimes subtotally or even totally divided) may be functionally masked at the outset, only to become evident hours, days, or weeks later.

In open injuries, tendon lacerations can often be diagnosed by the abnormal stance of the involved part of the hand and almost always by careful functional examination. If the diagnosis is not obvious, but the location of the wound raises the possibility of tendon injury, direct examination of the wound is indicated. Visualization of flexors can be difficult anywhere, whereas visualization of extensors is difficult mainly when they lie proximal to the metacarpal necks.

Occasionally the emergency physician will see a closed profundus tendon rupture. These injuries are often referred to as “jersey finger” because it often occurs when a tackler grasps another's jersey and the jersey is ripped from the tackler's hand. Such an injury almost always follows sudden violent stretch of the flexor, after which the patient is unable to flex the distal phalanx.

Treatment

Obtain immediate consultation with a hand specialist. Dress the wound after irrigation, and splint the wrist and hand. Remove jewelry and snug garments, and elevate the extremity until definitive treatment can be given. Flexor tendon repair may be delayed as long as 10 days without compromising the eventual outcome. However, early evaluation by a hand surgeon is advisable. If tendon repair is to be delayed, the wound should be sutured and appropriate antibiotics administered (eg, cefazolin, 1–2 g intravenously, followed by cephalexin, 500 mg orally four times daily for 3–5 days).

Disposition

Visualization of a lacerated tendon sheath is a reason for referral unless the entire course of the tendon gliding beneath the laceration is observed to be intact. If in doubt, refer immediately, because neglected partial tendon lacerations can go on to rupture.

Nerve Injuries

Clinical Findings

Early diagnosis is crucial. The cause and nature of injury, the symptoms, or the location and depth of a laceration may suggest possible nerve injury. If careful motor and sensory examination is performed (Figures 29–18 and 29–19), few significant nerve injuries will be missed.

Treatment

Appropriate dressing and splinting should be applied when indicated and the patient warned about injury to anesthetized skin until definitive treatment can be given.

Disposition

Refer the patient to a hand surgeon, and determine when the patient is to be transferred for definitive care.

High-Pressure Injection Injuries

Essentials of Diagnosis

• Initial appearance of hand may show only pinpoint portal of entry and look deceptively normal
• Obtain an X-ray
• Ask about the type, amount, and velocity of the injected material

Clinical Findings

High-pressure jets of a variety of hot and cold fluids (eg, grease, water, plastics, organic solvents) and gases are widely used in industry. Accidental penetration of the skin through a pinpoint portal of entry may result in devastating damage, even though the initial (postinjection) appearance of the hand or other body part is usually deceptively normal. This is because the foreign material spreads instantly along tissue planes and is widely distributed in the hand or other part. Spread of material up a flexor tendon sheath after penetration of a digital pad is quite common. An X-ray should be obtained, because some injected materials are radiopaque (eg, lead-based paint). When a chemical, inflammatory, or thermal response becomes manifest 4–12 hours after injury, extensive ischemia and tissue necrosis may be seen. Important historical factors are the type, amount, and velocity of the injected material and the anatomic location. The type of material injected is the most important clue to the severity of the injury.

Treatment and Disposition

Give analgesics for pain if necessary, and splint the extremity in a sling for comfort. Digital blocks are contraindicated due to the possibility of increased tissue pressure and vascular compromise. Obtain X-rays.

Give nothing by mouth, and consult a hand surgeon immediately regarding referral. Prompt tetanus prophylaxis, systemic antibiotics, and decompressive surgery (eg, fasciotomy) must be arranged in most cases. Even so, the prognosis for maintaining circulation and salvaging function is often dismal.

Closed Compartment Syndromes

Essentials of Diagnosis

• History of progressive pain and rock-hard compartment
• Pain on passive movement
• Hypoesthesia or paralysis of the digits

General Considerations

A compartment syndrome (eg, congestion progressing to various degrees of ischemia) can occur in any space of the digit, hand, forearm, or arm. It may involve a single space (eg, extensor and flexor compartments of the forearm and intrinsic muscle compartments of the hand). Obstructed venous flow leads to microvascular stagnation and death of muscle, fat, and nerves. Compartment syndrome may result from external compression (eg, a tight cast, prolonged pressure against an extremity of a comatose patient) or from internal swelling (eg, from severe bleeding, crush injury, burn, fracture, allergy, or infectious inflammatory reaction). The fate of a neglected case in which surgical decompression has not been performed is late fibrosis and severe functional impairment.

Clinical Findings

The typical patient presents with a history of progressive severe pain (eg, throbbing) and a rock-hard compartment. When the whole forearm and hand are involved, there is hypoesthesia, reluctance or inability to move the digits, and pain on passive extension of flexed digits. Pain perception may be lost as pressure on the nerves destroys their conducting ability.

Treatment

Treatment is supportive until definitive surgical decompression can be performed. Support the limb in a sling, and give analgesics for pain. The affected hand should be reassessed frequently for signs of circulatory compromise. Pallor, reduced capillary refill, loss of doppler pulses and increasing pain should alert the physician to the need for fasciotomy. In the absence of prompt surgical care, bedside escharotomy along the dorsal interosseus muscle compartments of the hand may release significant subcutaneous pressure. The incision should reach down to the pliable or fatty tissues, and extend the length of the eschar. If the eschar involves the forearm, mid-lateral incisions may be performed. This procedure should only be performed in the ED if the wait for definitive decompression will lead to prolonged tissue ischemia.

Disposition

Urgent hospitalization for surgical decompression under the care of a hand specialist is indicated.

Mangling Injuries

Clinical Findings

Mangling injuries include gunshot and blast wounds, severe open crush wounds, severe bites by large animals, and a large variety of ripping or tearing injuries (ie, lawnmower- or snowblower-associated injuries). The common denominators are multitissue involvement, distortion, and significant wound contamination.

Treatment

Rapid initiation of supportive measures; loose, bulky, sterile dressing and splinting; immediate administration of antibiotics (eg, cefazolin, 50–100 mg/kg/d intravenously or intramuscularly in 2–3 divided doses); and definitive surgical treatment are important to a successful outcome.

Disposition

All such injuries require immediate hospitalization and referral to a hand specialist for operative debridement and repair.

2Flexor and Proximal Extensor Tendon Injuries Are Discussed with Flexor Tendon Injuries Later in This Chapter.

Removal of Rings

All rings, bracelets, wristwatches, and snug shirtsleeves and coat sleeves should be prophylactically removed whenever injury, surgery, infection, or other cause of acute swelling of any part of the hand exists. Failure to do so may lead to serious congestion and unnecessary complications.

A ring on a swollen finger can be removed in three ways:

1. Lubricate the skin with soap and carefully slip off the ring.

2. Wrap the digit snugly with a string from the distal tip to just below the ring, and in that way “milk” edema out of the digit so that the ring can be removed over the string.

3. Cut the ring with a commercial ring cutter, spread it with two pairs of pliers, and remove it. This is the preferred method when there is significant digital injury or swelling distal to the ring.

Snakebite

See Chapter 46 for treatment.