HAND INJURIES

EPIDEMIOLOGY

Metacarpal and phalangeal fractures are common, comprising 10% of all fractures; >50% of these are work related.

The 1998 United States National Hospital Ambulatory Medical Care Survey found phalangeal (23%) and metacarpal (18%) fractures to be the second and third most common hand and forearm fractures following radius fractures. They constitute anywhere from 1.5% to 28% of all emergency department visits, depending on survey methods.

Location: Border digits are most commonly involved. The small finger axis is the most commonly injured and may constitute 37% of total hand fractures. Studies present conflicting data on incidence. A 1996 study in Injury indicated a series of 1,358 hand fractures were distributed as follows: 57.4% proximal phalanx, 30.4% middle phalanx, 12.2% metacarpal.

Male-to-female ratios run from 1.8:1 to 5.4:1, with higher ratios seen in the age groups associated with the greatest incidence (sports injuries in the early third decade, workplace injuries in the fifth decade, and falls in the seventh decade).

ANATOMY

Metacarpals

They are bowed, concave on palmar surface.

They form the longitudinal and transverse arches of the hand.

The index and long finger carpometacarpal (CMC) articulation is rigid.

The ring and small finger CMC articulation is flexible.

Three palmar and four dorsal interosseous muscles arise from metacarpal shafts and flex the metacarpophalangeal (MCP) joints.

These muscles create deforming forces in the case of metacarpal fractures, typically flexing the

fracture (apex dorsal angulation).

Phalanges

Proximal phalanx fractures usually angulate into extension (apex volar).

• The proximal fragment is flexed by the interossei.

• The distal fragment is extended by the central slip.

Middle phalanx fractures are unpredictable.

MECHANISM OF INJURY

A high degree of variation in mechanism of injury accounts for the broad spectrum of patterns seen in skeletal trauma sustained by the hand.

Axial load or “jamming” injuries are frequently sustained during ball sports or sudden reaches made during everyday activities such as to catch a falling object. Patterns frequently resulting from this mechanism are shearing articular fractures or metaphyseal compression fractures.

Distal phalanx fractures usually result from crush injuries and are comminuted tuft fractures.

Axial loading along the upper extremity must also make one suspicious of associated injuries to the carpus, forearm, elbow, and shoulder girdle.

Diaphyseal fractures and joint dislocations usually require a bending component in the mechanism of injury, which can occur during ball-handling sports or when the hand is trapped by an object and is unable to move with the rest of the arm.

Individual digits can easily be caught in clothing, furniture, or workplace equipment to sustain torsional mechanisms of injury, resulting in spiral fractures or more complex dislocation patterns.

Industrial settings or other environments with heavy objects and high forces lead to crushing mechanisms that combine bending, shearing, and torsion to produce unique patterns of skeletal injury and associated soft tissue damage.

Ring avulsion injuries result in severe soft tissue injury ranging from laceration to complete amputation.

CLINICAL EVALUATION

History: A careful history is essential because it may influence treatment. It should include the patient’s:

• Age

• Hand dominance

• Occupation

• Systemic illnesses

• Mechanism of injury: crush, direct trauma, twist, tear, laceration, etc.

• Time of injury (for open fractures)

• Exposure to contamination: barnyard, brackish water, animal/human bite

• Treatment provided: cleansing, antiseptic, bandage, tourniquet

• Financial issues: workers’ compensation

Physical examination includes:

• Digital viability (capillary refill should be <2 seconds)

• Neurologic status (documented by two-point discrimination [normal is 6 mm] and individual muscle testing)

• Rotational and angulatory deformity

• Range of motion (documented by goniometer)

• Malrotation at one bone segment is best represented by the alignment of the next, more distal segment. This alignment is best demonstrated when the intervening joint is flexed to 90 degrees. Comparing nail plate alignment is an inadequate method of evaluating rotation.

  RADIOGRAPHIC EVALUATION

Posteroanterior, lateral, and oblique radiographs of the affected digit or hand should be obtained. Injured digits should be viewed individually to minimize overlap of other digits over the area of interest.

CLASSIFICATION

Descriptive

Open versus closed injury

Bone involved

Location within bone

Fracture pattern: comminuted, transverse, spiral, vertical split

Presence or absence of displacement

Presence or absence of deformity (rotation and/or angulation)

Extra-articular versus intra-articular fracture

Stable versus unstable

Open Fractures

Swanson, Szabo, and Anderson

Type I: Clean wound without significant contamination or delay in treatment and no systemic illness

Type II: One or more of the following:

Contamination with gross dirt/debris, human or animal bite, warm lake/river injury, barnyard injury

Delay in treatment >24 hours

Significant systemic illness, such as diabetes, hypertension, rheumatoid arthritis, hepatitis, or asthma

Rate of infection: Type I injuries (1.4%)

Type II injuries (14%)

Neither primary internal fixation nor immediate wound closure is associated with increased risk of

infection in type I injuries. Primary internal fixation is not associated with increased risk of infection in type II injuries.

Primary wound closure is appropriate for type I injuries, with delayed closure appropriate for type II injuries.

Orthopaedic Trauma Association Classification of Metacarpal and Phalangeal Fractures

See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

TREATMENT: GENERAL PRINCIPLES

“Fight-bite” injuries: Any short, curved laceration overlying a joint in the hand, particularly the MCP joint, must be suspected of having been caused by a tooth. These injuries must be assumed to be contaminated with oral flora and should be addressed with broad-spectrum antibiotics (need anaerobic coverage) and irrigation and debridement.

Animal bites: Antibiotic coverage is needed for Pasteurella and Eikenella.

There are essentially six major treatment alternatives:

• Immediate motion

• Temporary splinting

• Closed reduction and internal fixation (CRIF)

• Open reduction and internal fixation (ORIF)

• Immediate reconstruction

• External fixation

The general advantages of entirely nonoperative treatment are lower cost and avoidance of the risks and complications associated with surgery and anesthesia. The disadvantage is that stability is less assured than with some form of operative fixation.

CRIF is expected to prevent overt deformity but not to achieve an anatomically perfect reduction. Pin tract infection is the prime complication that should be mentioned to patients in association with CRIF, unless K-wires are buried.

Open treatments are considered to add the morbidity of surgical tissue trauma, titrated against the presumed advantages of the most anatomic and stable reduction.

Critical elements in selecting between nonoperative and operative treatment are the assessments of rotational malalignment and stability.

• If carefully sought, rotational discrepancy is relatively easy to determine.

• Defining stability is somewhat more difficult. Some authors have used what seems to be the very reasonable criterion of maintenance of fracture reduction when the adjacent joints are taken through at least 30% of their normal motion.

Contraction of soft tissues begins approximately 72 hours following injury. Motion should be instituted by this time for all joints stable enough to tolerate rehabilitation.

General indications for surgery include:

• Open fractures

• Unstable fractures

• Irreducible fractures

• Multiple fractures

• Fractures with bone loss

• Fractures with tendon laceration, neurovascular injury, or soft tissue injury requiring coverage

Treatment of stable fractures:

• Buddy taping or splinting is performed, with repeat radiographs in 1 week.

• Initially unstable fractures that are reduced and then converted into a stable position: External immobilization (cast, cast with outrigger splint, gutter splint, or anterior–posterior splints) or percutaneous pinning which prevents displacement and permits earlier mobilization.

Treatment of unstable fractures:

• Unstable fractures that are irreducible by closed means or exhibit continued instability despite closed treatment require CRIF or ORIF, including Kirschner wire fixation, interosseous wiring, tension band technique, interfragmentary screws alone, or plates and screws.

Fractures with segmental bone loss

• These continue to be problematic. The primary treatment should be directed to the soft tissues, maintaining length with Kirschner wires or external fixation. These injuries usually require secondary procedures, including bone grafting.

  MANAGEMENT OF SPECIFIC FRACTURE PATTERNS

  Metacarpals

  Metacarpal Head

Fractures include:

• Epiphyseal fractures

• Collateral ligament avulsion fractures

• Oblique, vertical, and horizontal head fractures

• Comminuted fractures

• Boxer’s fractures with joint extension

• Fractures associated with bone loss

Most require anatomic reduction (if possible) to reestablish joint congruity and to minimize posttraumatic arthrosis.

• Stable reductions of fractures may be splinted in the “protected position,” consisting of metacarpal–phalangeal flexion >70 degrees to minimize joint stiffness (Fig. 24.1).

• Displaced metacarpal head fractures usually require open reduction internal fixation with K-

  wires or headless compression screws.

   

   

   

Early range of motion is essential.

Metacarpal Neck

Fractures result from direct trauma with volar comminution and dorsal apex angulation. Most of these fractures can often be reduced closed, but maintenance of reduction may be difficult (Fig. 24.2).

The degree of acceptable deformity varies according to the metacarpal injured:

• Less than 10-degree angulation for the second and third metacarpals

• Less than 30- to 40-degree angulation for the fourth and fifth metacarpals

Unstable fractures require operative intervention with either percutaneous pins (may be intramedullary or transverse into the adjacent metacarpal) or plate fixation.

Metacarpal Shaft

Nondisplaced or minimally displaced fractures can be reduced and splinted in the protected position. Central metacarpal fractures (third and fourth) are usually more stable due to the intermetacarpal ligaments.

Operative indications include rotational deformity, dorsal angulation >10 degrees for second and third metacarpals, and >20 degrees for fourth and fifth metacarpals.

Generally, malrotation is not acceptable. Ten degrees of malrotation (which risks as much as 2 cm of overlap at the digital tip) should represent the upper tolerable limit.

Operative fixation may be achieved with either closed reduction and percutaneous intermetacarpal pinning or ORIF with interfragmentary screws, intramedullary nails, or plate and screws.

Metacarpal Base

Fingers

Fractures of the bases of the second through fifth metacarpals may be associated with CMC fracture-dislocations. In addition to a posterior anterior radiograph, it is important to get a true lateral and a 30-degree pronated from lateral view. Displaced fractures require CRIF versus ORIF.

The reverse Bennett fracture is a fracture-dislocation of the base of the fifth metacarpal/hamate.

• The proximal metacarpal fragment is displaced proximally by the pull of the extensor carpi ulnaris.

• This fracture often requires surgical intervention with CRIF versus ORIF.

  Thumb

Extra-articular fractures: These are usually transverse or oblique. Most can be held by closed reduction and casting, but some unstable fractures require closed reduction and percutaneous pinning. The basal joint of the thumb is quite forgiving, and an anatomic reduction of an angulated shaft fracture is not essential.

Intra-articular fractures (Figs. 24.3 and 24.4):

Type I: Bennett fracture: The fracture line separates a major part of the metacarpal from the volar lip fragment, producing a disruption of the first CMC joint. The distal metacarpal is displaced proximal, radial, and dorsal by abductor pollicis longus (APL) and extensor pollicis longus. The APL pull also supinates the metacarpal. The adductor pollicis displaces the metacarpal head into the palm.

Type II: Rolando fracture: It requires greater force than a Bennett fracture; presently it is used to describe a comminuted Bennett fracture, a “Y” or “T” fracture, or a fracture with dorsal and palmar fragments.

Treatment: Both types I and II fractures of the base of the first metacarpal are unstable and should be treated with closed reduction and percutaneous pins, or ORIF.‌

Proximal and Middle Phalanges

Intra-Articular Fractures

Condylar fractures: single, bicondylar, osteochondral

• They require anatomic reduction; CRIF versus ORIF should be performed for any displacement. Consider CRIF for nondisplaced fractures since they are frequently unstable and difficult to assess maintenance of reduction in a splint or cast.

• Comminuted intra-articular phalangeal fractures should be treated with reconstruction of the articular surface, if possible. Severely comminuted fractures that are deemed nonreconstructible

  may be treated closed with early protected mobilization. The surgeon should discuss with the patient the possibility of secondary procedures.

  Proximal Interphalangeal Fracture-Dislocations

Volar lip fracture of middle phalangeal base (dorsal fracture-dislocation)

• Treatment is controversial and depends on the percentage of the articular surface fractured.

• Hyperextension injuries without a history of dislocation and with <30% to 35% articular (nondisplaced) involvement: 20-degree dorsal block splint and buddy tape to the adjacent digit

  × 3 weeks, then buddy tape active and active assisted range of motion

• Forty percent or more articular involvement: usually unstable. Dynamic external fixator (Suzuki/Slade with 0.045 in K-wires and rubber bands). Add ORIF if fragments need further reduction. If too comminuted or chronic and 40% to 50% articular involvement: volar plate arthroplasty versus hemi-hamate arthroplasty; >50% articular involvement: hemi-hamate arthroplasty

Dorsal lip fracture of middle phalangeal base (volar fracture-dislocation)

• Usually, this is the result of a central slip avulsion.

• Fractures with <1 mm of displacement: These may be treated closed with splinting, as in a boutonniere injury.

• Fractures with >1 mm of displacement or volar subluxation of the proximal interphalangeal

  (PIP) joint: Operative stabilization of the fracture is indicated. CRIF versus ORIF.

• Pilon fractures (Suzuki/Slade with 0.045 in K-wires and rubber bands). Add ORIF if fragments need further reduction.

  Extra-Articular Fractures

  Add: Shaft fractures. If displaced or unstable, CRIF versus ORIF. Epibasilar proximal phalanx fractures are usually apex volar. Consider CRIF with trans-MCP joint pin while flexing MCP joint.

Fractures at the base of the middle phalanx tend to angulate apex dorsal, whereas fractures at the neck angulate the apex volarly owing to the pull of the sublimis tendon (Fig. 24.5). Closed reduction should be attempted initially with finger-trap traction followed by splinting.

Fractures in which a stable closed reduction cannot be achieved or maintained should be addressed with closed reduction and percutaneous pinning or ORIF with mini-fragment implants.

Distal Phalanx (Fig. 24.6)

Intra-Articular Fractures

Dorsal lip

• A mallet finger may result from a fracture of the dorsal lip with disruption of the extensor tendon. Alternatively, a mallet finger may result from a purely tendinous disruption and may therefore not be radiographically apparent.

• Treatment remains somewhat controversial.

  • Some recommend nonoperative treatment for all mallet fingers with full-time extension splinting for 6 to 8 weeks, including those with a significant articular fracture and joint subluxation.

  • Others recommend CRIF for displaced dorsal base fractures with subluxation. Various closed pinning techniques are possible, but the mainstay is extension block pinning.

Volar lip

• This is associated with flexor digitorum profundus rupture (“jersey finger”: seen in football and rugby players, most commonly involving the ring finger).

• Treatment is primary repair, especially with large, displaced bony fragments.

  Extra-Articular Fractures

These are transverse, longitudinal, and comminuted (nail matrix injury is very common).

Treatment consists of closed reduction and splinting.

The splint should leave the PIP joint free but usually needs to cross the distal interphalangeal (DIP) joint to provide adequate stability. Aluminum and foam splints or plaster of Paris are common materials chosen.

CRIF is indicated for shaft fractures with wide displacement because of the risk for nail bed incongruity and later nail plate nonadherence.

Nail Bed Injuries (Fig. 24.7)

These are frequently overlooked or neglected in the presence of an obvious fracture, but failure to address such injuries may result in growth disturbances of the nail.

Acute subungual hematomas may be evacuated with cautery or a hot paper clip.

If the nail plate has been avulsed at its base, it should be removed, cleansed with povidone-iodine, and retained to replace under the eponychium.

Nail bed disruptions should be carefully sutured with 6–0 chromic catgut under magnification.

Recent evidence indicates Octyl cyanoacrylate (Dermabond) is a viable method of nail bed repair with the advantage of being a faster procedure.

The aluminum suture package material may be used if the original nail plate is not usable as a biologic dressing.

Carpometacarpal Joint Dislocations and Fracture-Dislocations

Dislocations at the finger CMC joints are usually high-energy injuries with involvement of associated structures, including neurovascular injury.

Overlap on the lateral x-ray obscures accurate depiction of the injury pattern. A 30-degree pronated view from lateral will help elucidate.

When fracture-dislocations include the dorsal cortex of the hamate, computed tomography may be necessary to better evaluate the pathoanatomy.

Most thumb CMC joint injuries are fracture-dislocations rather than pure dislocations. Terms associated with these fracture-dislocations are Bennett (partial articular) and Rolando (complete articular) fractures.

Dorsal finger CMC fracture-dislocations cannot usually be held effectively with external splints/casts alone. CRIF versus ORIF is the treatment of choice.

Metacarpophalangeal Joint Dislocations (Fig. 24.8)

Dorsal dislocations are the most common.

Simple dislocations are reducible and present with a hyperextension posture.

They are really subluxations, because some contact usually remains between the base of proximal phalanx and the metacarpal head.

Reduction can be achieved with simple flexion of the joint; excessive longitudinal traction on the finger should be avoided, since this could interpose the volar plate. Wrist flexion to relax the flexor tendons may assist reduction.

The other variety of MCP joint dislocation is a complex dislocation, which is by definition irreducible, most often the result of volar plate interposition.

• Complex dislocations occur most frequently in the index finger.

• A pathognomonic x-ray sign of complex dislocation is the appearance of a sesamoid in the joint space.

Most dorsal dislocations are stable following reduction and do not need surgical repair of the

ligaments or volar plate.

Volar dislocations are rare but are particularly unstable.

Volar dislocations are at risk for late instability and should have repair of the ligaments.

Open dislocations may be either reducible or irreducible.

Thumb Metacarpophalangeal Joint Dislocations

The thumb MCP joint, in addition to its primary plane of flexion and extension, allows abduction–adduction and a slight amount of rotation (pronation with flexion).

With a one-sided collateral ligament injury, the phalanx tends to subluxate volarly in a rotatory fashion, pivoting around the opposite intact collateral ligament.

The ulnar collateral ligament may have a two-level injury consisting of a fracture of the ulnar base of proximal phalanx with the ligament also ruptured off the fracture fragment.

Of particular importance is the proximal edge of the adductor aponeurosis that forms the anatomic basis of the Stener lesion. The torn ulnar collateral ligament stump comes to lie dorsal to the aponeurosis and is thus prevented from healing to its anatomic insertion on the volar, ulnar base of the proximal phalanx (Fig. 24.9).

The true incidence of the Stener lesion remains unknown because of widely disparate reports.

Nonoperative management (thumb spica cast versus splint × 6 weeks) is the mainstay of treatment for partial thumb MCP joint collateral ligament injuries.

If the MCP joint opens >30 degrees or >15 degrees from the contralateral side, tested at 30 degrees of flexion, it is a complete thumb MCP joint collateral ligament injury and surgery is indicated for the ulna collateral ligament and is controversial for the radial collateral ligament. The ligament can be repaired with a bone suture anchor. If the injury is chronic and there is no adequate ligament to repair, a free tendon graft through bone tunnels may be employed.

Proximal Interphalangeal Joint Dislocations

Dislocations of the PIP joint have a high rate of missed diagnoses that are passed off as “sprains.”

Although large numbers of incomplete injuries occur (especially in ball-handling sports), complete disruptions of the collateral ligaments and the volar plate are also frequent (50% occur in the long finger followed in frequency by the ring finger).

Congruence on the lateral radiograph is the key to detecting residual subluxation.

Residual instability is quite rare in pure dislocations, as opposed to fracture-dislocations, in which it is the primary concern.

Recognized patterns of dislocation other than complete collateral ligament injury are dorsal dislocation, pure volar dislocation, and rotatory volar dislocation.

Dorsal dislocations involve volar plate injury (usually distally, with or without a small flake of bone).

For pure volar dislocations, the pathologic findings are consistently damage to the volar plate, one collateral ligament, and the central slip.

Volar or lateral dislocations may be irreducible if the head of proximal phalanx passes between the central slip and the lateral bands, which can form a noose effect and prevent reduction.

In pure dislocations, stiffness is the primary concern. Stiffness can occur following any injury pattern.

Chronic missed dislocations require open reduction with a predictable amount of subsequent stiffness.

Treatment

• Once reduced, rotatory volar dislocations, isolated collateral ligament ruptures, and dorsal dislocations congruent in full extension on the lateral radiograph can all begin immediate active range of motion with adjacent digit strapping.

• Dorsal dislocations that are subluxated on the extension lateral radiograph require a few weeks of extension block splinting.

• Volar dislocations with central slip disruptions require 4 to 6 weeks of PIP extension splinting,

  followed by nighttime static extension splinting for 2 additional weeks. The DIP joint should be unsplinted and actively flexed throughout the entire recovery period.

• Open dorsal dislocations usually have a transverse rent in the skin at the flexion crease. Debridement of this wound should precede reduction of the dislocation.

  Distal Interphalangeal and Thumb Interphalangeal Joint Dislocations

Dislocations at the DIP/IP joint are often not diagnosed initially and present late.

Injuries are considered chronic after 3 weeks.

Pure dislocations without tendon rupture are rare, usually result from ball-catching sports, are primarily dorsal in direction, and may occur in association with PIP joint dislocations.

Transverse open wounds in the volar skin crease are frequent.

Injury to a single collateral ligament or to the volar plate alone at the DIP joint is rare.

Nonoperative Treatment

Reduced dislocations that are stable may begin immediate active range of motion.

The rare unstable dorsal dislocation should be immobilized in 20 degrees of flexion for up to 3 weeks before instituting active range of motion.

• The duration of the immobilization should be in direct proportion to the surgeon’s assessment of joint stability following reduction.

• Complete collateral ligament injuries should be protected from lateral stress for at least 4

  weeks.

Should pin stabilization prove necessary because of recurrent instability, a single longitudinal Kirschner wire is usually sufficient.

Operative Treatment

Delayed presentation (>3 weeks) of a subluxated joint may require open reduction to resect scar tissue and to allow tension-free reduction.

Open dislocations require thorough debridement to prevent infection.

The need for fixation with a Kirschner wire should be based on the assessment of stability, and it is not necessarily required for all open dislocations.

The duration of pinning should not be >4 weeks, and the wire may be left through the skin for easy removal.

COMPLICATIONS

Malunion: Angulation can disturb intrinsic balance and also can result in prominence of metacarpal heads in the palm with pain on gripping. Rotational or angulatory deformities, especially of the second and third metacarpals, may result in functional and cosmetic disturbances, emphasizing the need to maintain as near anatomic relationships as possible.

Nonunion: This is uncommon, but it may occur with extensive soft tissue injury and bone loss, as well as with open fractures with gross contamination and infection. It may necessitate debridement, bone grafting, or flap coverage.

Infection: Grossly contaminated wounds require meticulous debridement and appropriate antibiotics depending on the injury setting (e.g., barnyard contamination, contaminated water, bite wounds), local wound care with debridement as necessary, and possible delayed closure.

MCP joint extension contracture: This may result if splinting is not in the protected position (i.e., MCP joints at >70 degrees) leading to soft tissue contracture.

Loss of motion: This is secondary to tendon adherence, especially at the level of the PIP joint.

Posttraumatic osteoarthritis: This may result from a failure to restore articular congruity.