The hand is an instrument of performance and protection. Whether
at war, work, competition, or recreation, an individual’s
reflexes routinely place the hand in harm’s way to protect
the head and body. Accidents inevitably occur, resulting in fractures of
the metacarpals and phalanges and other injuries. This Instructional
Course Lecture addresses, in particular, the craft of reduction
and stabilization of displaced, irreducible, and unstable fractures
of the hand as an integral part of reestablishing skeletal integrity
and refined digital function. The goals of treatment include returning
manual laborers to their work or to the practice of their special
skills, professionals to their tasks, students to their classrooms,
writers to their pens, musicians to their instruments, artists to
their brushes and easels, athletes to their contests, parents to
their families, children to life’s enjoyments, and increasing
numbers of the world’s population to a variety of digital
keyboards and computers.
Fracture management should be principle-driven. These principles
include the attainment of anatomical (or near-anatomical) position,
adequate stability to allow both fracture-healing and early active
digital motion, and minimization of additional soft-tissue damage
when fixation of the fracture is required1.
Function follows form. Although there is some tolerance for deformity,
excessive angulation or rotation of a fractured digit may obstruct
the motion and function of an adjacent digit and, consequently,
the hand. Bone angulation, shortening, or a combination of the two
affects muscle-tendon tension, leading to digital deformity as well
as to loss of motion, strength, power, and endurance.
While the prevalence, rate of development, and severity of posttraumatic
arthritis and pain in the joints of the hand may be less than those
in larger joints, particularly weight-bearing joints, there should
be no complacency in the pursuit to reestablish joint congruity
when repairing an intra-articular fracture2-4.
A single millimeter of incongruity may be acceptable, but an effort
should always be made to correct an offset of 2 mm or more, especially
if it is accompanied by joint subluxation.
Fracture stability need not be rigid but must be reliable. The method
or the implant or implants selected do not necessarily have to be
the strongest available, but a threshold of stabilizing force that
will reliably allow fracture-healing in concert with early rehabilitation
must be achieved. Fracture fixation only needs to be strong enough
to immobilize the fracture until the strength of the healing callus
surpasses that of the fixation. Although stability may not hasten
healing, it ensures the process by protecting tissue revascularization
during repair. Fracture stability may also inhibit infection.
Surgical incision, especially when it is accompanied by periosteal
violation and particularly when flexor-tendon zone II is involved5, carries the risk of functionally limiting
scar formation. The physician must balance the potential benefit
of the increased biomechanical stability that may be gained through
surgical treatment against the risk of consequent digital stiffness.
Anatomical reduction and fracture stability help to control and minimize
pain and are instrumental in permitting the early active range-of-motion
exercises that are the cornerstone of rehabilitation and recovery.
Placement of the hand and wrist in a functional or "safe" ("rehabilitation-ready")
position neutralizes and balances the muscle forces acting at the
fracture site. (In a rehabilitation-ready position, the wrist is
extended 15° to 20°, the metacarpophalangeal joints are flexed 70°
or more, and the proximal interphalangeal joints are in 0° to 10°
of flexion.) This position also places the digital joint ligaments
at maximum length to prevent permanent contracture and is particularly
important in reduced fractures that are considered stable without
the application of implants. A functional hand and wrist position
is also instrumental in placing the extrinsic and intrinsic muscles
at or near their resting tension, at which point they can generate the
maximum strength and power that are so critical for the recovery
of digital motion. Once motion is regained, further muscle strength,
power, and endurance follow more easily. The treatment of edema
and the promotion of softening, mobilization, and desensitization
of integumentary scar tissue may proceed concurrently.
Plain radiographs alone are almost always adequate for the evaluation
of hand fractures. Metacarpal fractures may be difficult to evaluate
in the lateral plane because of overlap of adjacent metacarpals.
Oblique radiographs with the hand pronated or supinated (or both)
at 30° to 45° are helpful. Oblique radiographs are also helpful
in the evaluation of intra-articular fractures. Avulsion fractures
of the proximal, dorsal, and palmar lips of the phalanges as well
as their extent and degree of displacement sometimes may be seen
and fully appreciated only on true lateral radiographs. The true
extent of the angulation of an extra-articular proximal phalangeal
fracture near a joint often may be accurately assessed only on a true
lateral radiograph6. Oblique radiographs
may create an optical illusion of less angulation than truly exists,
which may lead the surgeon into the complacency of accepting angulation that
should actually be corrected. A computerized axial tomography scan
occasionally may be useful, especially in the assessment of an intra-articular
fracture, particularly when there is intra-articular comminution.
The majority of hand fractures are closed, simple, and stable. They
are unlikely to move from the position that they are in when they
are initially seen, even during the process of rehabilitation of
the digits. Radiographs demonstrate minimal displacement (less than
1 to 2 mm of translation and less than 10° to 20° of angulation)
or no displacement. These fractures may not be associated with any
apparent clinical deformity on visual inspection. A digital or wrist
block may allow the physician to recognize the presence of functional
deformity or instability. These fractures require only a brief period of
static or dynamic splinting or even buddy-taping to an adjacent finger,
and a short period of rehabilitation7-14.
Some comparable but displaced fractures may be stable following
closed manipulative reduction, and they may be treated similarly.
They should be monitored during the first few weeks after reduction
until fracture callus is visualized on radiographs, as loss of reduction
may occur. The course of treatment is typically uncomplicated, and
the functional outcomes are commonly good.
More severe fractures may be displaced and may be associated with
visible deformities because of their configuration, periosteal disruption,
and unbalanced muscle forces. If these fractures are unstable following
reduction, they will require fixation with an implant to maintain
anatomical position during fracture-healing and to allow simultaneous
rehabilitation. A digital nerve block with local anesthesia followed
by observation of digital motion or by stress-testing may assist
the physician in determining whether the fracture is stable and whether
fixation is necessary.
The vast majority of reducible but unstable closed simple fractures
may be reliably treated with transcutaneous Kirschner-wire fixation.
This type of treatment has been termed closed reduction and internal
fixation (CRIF)15,16. Soft-tissue
damage from insertion of this type of implant is usually minimal.
While closed reduction and internal fixation may be performed
with use of ordinary radiographic control, c-arm fluoroscopy substantially
simplifies the procedure by allowing instantaneous adjustments of
the fracture reduction and of the insertion site, angle, and depth
of the wire in two planes or more. A pointed reduction forceps is instrumental
in achieving and maintaining fracture reduction. If the reduction
forceps is cannulated, wire insertion is further simplified. An
assistant holds and stabilizes the hand or finger while the surgeon
drills the wire into the proper position.
Open reduction is usually required for fractures that are irreducible
because of swelling, soft-tissue interposition, or interlocking
of the fragments. Following open reduction, internal fixation is
usually indicated because of fracture instability. It may also be
prudent to allow earlier and more intensive rehabilitation in these
situations in which more than ordinary scar-tissue formation is
anticipated. This type of treatment is designated as open reduction
and internal fixation (ORIF). Other relative indications for open reduction
and internal fixation include open fractures (especially those associated
with bone loss or other complex injuries); intra-articular, periarticular, comminuted,
and multiple fractures; fractures that have occurred in association
with other fractures in the same extremity; and fractures in multiply
injured or noncompliant patients. Open reduction and fixation with
Kirschner wires may be necessary in certain situations in which
closed reduction and internal fixation would ordinarily have been
done with radiographic assistance. Widgerow et al., for example,
reported that open reduction and internal fixation was successfully
performed in the absence of radiographic capability in a third-world
country17. This technique may
also be important when radiographic equipment is unavailable, broken down,
or malfunctioning or when there is a power failure. Meticulous attention
to surgical detail may overcome an absence or failure of technical
equipment in some situations. Mini-screws have been inserted through
small "portal-sized" 1 to 2-mm incisions. This
procedure is termed limited open reduction and internal fixation
(LORIF).
Open reduction and mini-internal fixation in the hand is less controversial
for the treatment of nonunion or malunion, for early arthrodesis
of an irreparable intra-articular fracture, and for later arthrodesis
in a hand with symptomatic posttraumatic arthritis than it is for
the treatment of acute fractures. Strong, reliable long-term fixation
is needed to support bone grafts, osteotomy sites, and arthrodesis sites,
which may need a longer healing time because of the extensive osseous
defects and the extensive dissection associated with these procedures.
Additionally, firm fixation is required so that early and intensive
therapy may be applied to inhibit or prevent adjacent tendon and
joint adhesions, especially when tenolysis or capsulotomy has been
performed concurrently.
Kirschner wires are the cornerstone of hand-fracture fixation7-18. They may be inserted either transcutaneously
after closed reduction of a fracture or following open reduction.
They do not compress but internally splint the bone while the fracture
heals. The fracture reduction should be as precise as possible prior
to the insertion of the wires in order to ensure optimal stability
of the fracture-implant construct.
Kirschner wires are inexpensive and almost universally available. They
require little additional instrumentation, may be inserted with
either hand or power-driven drills, and create little additional soft-tissue
trauma. They may form an integral component of other open wiring
techniques, such as figure-of-eight tension-band wiring and circumferential wiring.
They may also be used adjunctively to enhance the stability of almost
any other form of internal or external fixation. An oblique Kirschner
wire may add substantial additional stability to a construct that
is less than adequately stable. These wires are generally left in
place until fracture callus or healing is visible on radiographs
or for as long as they are tolerated. Fracture-healing is usually
sufficiently advanced at three to four weeks after insertion so
that the Kirschner wires may be removed.
Kirschner wires with a 0.045-in (1.1-mm) diameter may be used almost
universally in the hand. Occasionally, for larger bones, such as
the metacarpal or the proximal phalanx, Kirschner wires with a 0.062-in
(1.6-mm) diameter may be selected. For children and for smaller
bones, such as the middle or distal phalanges, wires with a 0.035-in (0.9-mm)
diameter may be the best choice.
Kirschner wires or their equivalents may be inserted into the medullary
canal of metacarpals and phalanges for fracture fixation15,16,19,20. When used in this fashion, these
devices may be left in place temporarily or permanently. The principal
difficulties include a lack of rotational control and delayed union
or nonunion. Fracture collapse may occur when Kirschner wires are removed
prematurely, which may result in nonunion or malunion of the fracture
and consequent digital stiffness. This risk increases with fracture
comminution21. Mini-screws, and
even mini-plates, may obviate this risk.
Mini-screws, mini-plates, and the instruments necessary to apply
them are relatively expensive compared with Kirschner wires and
other wiring systems. Their insertion is technically more demanding
than that of Kirschner wires, and there is less margin for error.
Specialized training and surgical experience are definite advantages
that enhance an individual’s proficiency in their use.
A sterile operating environment is mandatory. Good lighting, experienced personnel,
and reliable radiographic support are often critical to obtain a
successful result. The advantages of these implants are the added
stability provided by fracture compression and the resultant or
independent neutralization of bending, rotational, and shear forces
acting upon the fracture site. These features help to ensure timely
fracture-healing and to allow earlier and more intensive digital
rehabilitation.
A mini-screw is little more than a Kirschner wire with threads and
a head. Insertion of a mini-screw is associated with little if any
additional soft-tissue trauma compared with that associated with
insertion of a Kirschner wire22.
Drilling the proximal cortex to the same diameter as the screw threads
creates a "gliding hole" through which the mini-screw slides
without resistance until it engages the "core hole" that
has been drilled in the opposite cortex. The "core hole" has
the same diameter as the core of the mini-screw. This creates a
lag effect, resulting in compression at the fracture site.
Mini-plates must be used judiciously, especially on phalanges, since
the dissection necessary for their application may disrupt periosteal
circulation at the fracture site and may stimulate substantial fibroplasia
(scar formation)10,12,14. Mini-plates
are particularly useful for the treatment of open fractures associated
with bone loss and extensive comminution. Mini-plates have generic
anatomical or descriptive names; examples of those devices include
straight tubular and limited-contact mini-plates, mini-condylar
plates, mini-T or mini-L plates, and angled mini-plates. Mini-H
plates have been designed to facilitate digital replantations. Physiologically, these
mini-plates stabilize fractures by compression, neutralization,
or buttressing. In some instances they may compress the fracture
and neutralize the external forces acting upon it, and in others
they may buttress the fracture and neutralize the external forces
acting upon it. Compression and buttressing cannot take place concurrently
because they are diametrically opposed forces.
When a mini-plate is applied to compress a fracture, the fracture must
first be accurately reduced. The mini-plate is then stabilized on
one side of the fracture with mini-screws. On the other side of the
fracture, a hole is drilled eccentrically through the plate-hole
most distant from the fracture. When the mini-screw is inserted
into this hole and the screw head engages the plate-hole, it pulls
the mini-plate and the attached fragment toward the screw, placing
the fracture under compression. This is called the "spherical
gliding principle" of screw-head engagement of the plate-hole1. The fracture is placed under compression
while the mini-plate is placed under an equal amount of tension.
Thus, this construct is called a "compression plate" or
a "tension-band plate". The terms are synonymous.
The bone will not move until and unless the compressive force of
this "preload" is exceeded.
The Pratt incision (or a variation of it) has been the classic
dorsal utilitarian approach for fractures of the proximal phalanx23 (Fig. 1). A mid-axial incision may be preferable
for some fractures in an effort to move the zone of injury away
from the extensor mechanism and to minimize the risk of adhesions
to this tendon24,25 (Fig. 2). Metacarpals
may be approached through a direct longitudinal incision. If two
adjacent metacarpals are fractured, they usually may be approached through
a single incision made between them26,27 (Fig. 3). The fracture
is exposed by subperiosteal dissection initiated from the lateral
side in an effort to protect the gliding tissue on either side of
the extensor tendon.
Mini-external fixators may be used to treat a variety of hand fractures.
While their advantages include minimal or no exposure of the fracture
site and adequate stability, they have no compelling advantage over
Kirschner wires in the treatment of simple closed fractures of the
hand. Conversely, they may be especially useful for comminuted intra-articular
fractures; for the initial provisional and, sometimes, permanent
definitive fixation of severe open fractures; and for mutilating
injuries associated with soiling, comminution, bone loss, and full-thickness
skin loss28.
Ideally, a minimum of two threaded or smooth half-pins are inserted
on either side of the fracture. Pins with a 0.062-in (1.6-mm) diameter
are ordinarily used for smaller adult bones such as the middle and
distal phalanges and for children, whereas pins with a 0.08-in (2.0-mm) diameter
are used for adult metacarpals and proximal phalanges. Kirschner
wires with similar diameters may be substituted for half-pins. Smooth
pins are sufficient for short-term application (four to six weeks). They
are further stabilized when the mini-external fixator compresses
or distracts the fracture. Threaded pins provide more stability
than smooth pins, especially when a mini-external fixator is applied
for long-term (six-to-ten-week) definitive fixation of a fracture
with a defect that requires bone-grafting. Ancillary Kirschner wires
or mini-screws may be used in conjunction with a mini-external
fixator to secure larger fracture fragments. Occasionally, a mini-external
fixator may be used to support a mini-plate that spans but does
not independently secure a fracture.
Extensor tendon transfixion is more easily avoided in metacarpal
applications than in phalangeal applications. A longitudinal incision
of approximately 1 cm in the dorsal apparatus may avoid irritation
and allow limited motion of the digit. Pin sites are a source of
risk for infection and require daily wound care (cleaning and antiseptic
application). The prevalence of nonunion is related to the size
and severity of the bone defect while the prevalence of infection
is related to the size and severity of the wound and the degree
of initial contamination.
Bone-grafting may be indicated when there is a cortical defect
at the site of fixation of a mini-plate, comminution, a
bone defect, or atrophic nonunion1.
Cancellous bone from the proximal part of the ipsilateral ulna, the
distal part of the ipsilateral radius, or the ilium is the mainstay
for bone-grafting of defects in the hand. Cancellous bone may be
placed in the barrel of a syringe and compressed by the plunger29. The compacted cancellous bone may
then be disengaged from the barrel with use of a long spinal needle
inserted through the barrel outlet. This dense cancellous bone then
can be inserted to provide additional structural support at the
site of the defect. If there are any viable cells in the cancellous
bone, compacting increases their numbers per unit of volume. Although
not scientifically confirmed to date, it is our impression that
revascularization and incorporation occur more rapidly in compacted
than in noncompacted cancellous bone graft.
Unicortical bone grafts from the ilium, the proximal part of
the ipsilateral ulna, or the distal part of the ipsilateral radius,
or tricortical bone grafts from the iliac crest may be sculpted
to fit larger defects (1.5 cm in length or greater) or may be used
when the stability afforded by cortical bone is needed. Ball-and-socket or
mortise articulations at the bone graft-fracture junctions reestablish
bone length, alignment, and stability while providing a large cancellous
interface area for healing. Donor-site defects may be packed with
synthetic bone graft to minimize the risk of later fracture at that
site.
The unbalanced pull of the interosseous muscles and extrinsic
digital flexors on the distal fragment may cause dorsal angulation
of metacarpal fractures30,31.
Dorsal angulation of as much as 10° more than the motion afforded
at the carpometacarpal joints does not ordinarily cause a functional
deficit26,27. Compensatory carpometacarpal
motion allows accommodation of the metacarpal head in the palm of
the hand in slightly angulated fractures and prevents painful pressure
from a palmarly displaced metacarpal head when tools and implements
with a handle are grasped and used. The intermetacarpal ligaments
prevent more than 3 to 4 mm of shortening32.
The second and fifth metacarpals are more likely to shorten since
they have the suspensory effect of only one intermetacarpal ligament.
Approximately 7° of extensor lag develops in the fingers for each
2 mm of residual metacarpal shortening after fracture-healing33. In any case, angulation of more than
30°, shortening of more than 4 mm, or a combination of these findings
interferes with normal intrinsic muscle-tension dynamics and may
cause weakness, loss of endurance, cramping, and clawing, each of
which should be prevented by correction of the deformity30-34 (Fig. 4). The metacarpals are very intolerant
of malrotation. As little as 5° of malrotation may translate into
1.5 cm of digital overlap during finger flexion27,35.
Metacarpal shaft fractures may be classified by pattern. Simple fractures
may be transverse or oblique. Oblique fractures may be short (less
than twice the diameter of the bone adjacent to or at the site of
the fracture) or long (at least twice the adjacent bone diameter).
Long oblique fractures may be uniplanar or spiral. Short oblique
fractures are essentially always uniplanar. Other metacarpal shaft
fractures may have comminuted patterns or bone loss.
Transverse metacarpal shaft fractures may be caused by axial loading
but usually result from a dorsal impact. Undisplaced, minimally
displaced, and fully reduced fractures may be successfully treated
with protective splinting or functional bracing9,36,37.
Skin necrosis overlying the fracture is a risk. If displacement recurs
during the first three to four weeks of healing and before fracture
callus is visualized on radiographs, closed remanipulation and percutaneous
Kirschner-wire stabilization is indicated. Thereafter, open reduction
and either re-creation of the fracture or corrective osteotomy may
be necessary. In such cases, some type of internal fixation, often
a mini-plate, is indicated.
Some closed transverse metacarpal fractures may be accompanied
by such extensive swelling that reduction is impossible. Others
may redisplace after reduction because of extensive periosteal disruption.
In such instances, either intramedullary splinting (Fig. 5)20 or fixation with Kirschner or composite
wire38 or with straight tubular
or low-contact dynamic compression mini-plates26,27,39-48 may
provide an optimal solution. The use of two plate-holes on both
sides of the fracture, allowing the secure purchase of four cortices
(also on both sides of the fracture), provides sufficient and reliable
fixation (Fig. 6)26,27.
The treatment of short oblique fractures of the metacarpal shaft may
be similar to that of transverse fractures of the metacarpal shaft.
Alternatively, sagittal short oblique fractures may be treated with
a laterally inserted mini-lag (compression) screw. A five-hole mini-plate
is then centered with the middle hole over the fracture site and
is secured without compression by the insertion of mini-screws into
the center of the two plate-holes on either end of the mini-plate.
The center hole is left free to accommodate the underlying laterally
applied mini-lag screw26,27. A
mini-plate applied in this fashion is called a "neutralization
mini-plate." Such plates counteract the bending, rotational,
and shear forces that might act on the mini-lag screw. Coronal short
oblique fractures may be treated by application of a five-hole
straight tubular or low-contact dynamic compression mini-plate that
drives the adjacent corner of the fracture into the mini-plate.
A mini-lag screw is then inserted through the center plate-hole
and across the fracture26,27.
This is the strongest of the mini-plate constructs because it compresses
the fracture by both mini-plate and screw application.
An unstable long oblique fracture of the metacarpal shaft may be
treated with transcutaneous Kirschner wires if closed reduction
is performed and with either Kirschner wires or two or more mini-lag
screws if open reduction is performed26,27,39-46.
Although Kirschner wires may be used in cases of open reduction,
mini-lag screws provide more secure fixation and require no more
dissection than Kirschner wires do. The length of the fracture is
divided by the width of the bone adjacent to or at the site of the
fracture to determine the number of mini-screws that should be used.
If the fracture is twice as long as the adjacent bone diameter,
the fracture is divided into thirds and the mini-screws are inserted
at the juncture of each third. If the fracture is three times as
long as the adjacent bone diameter, the fracture is divided into
quarters and the mini-screws are inserted at the juncture of each
quarter. A mini-lag screw provides maximum compression when inserted perpendicular
to the fracture (in which case it is known as a compression screw)
and maximum shear resistance when inserted perpendicular to the
long axis of the bone (in which case it is known as a neutralization screw).
Uniplanar fractures are treated with at least one neutralization
screw. The remaining screw or screws may be inserted as compression
screws. In spiral long oblique fractures, the intervals for division
and insertion remain the same, but the spiral fracture plane is
followed (Fig. 7).
At one or more points, a mini-screw may be inserted both perpendicular
to the fracture and perpendicular to the long axis of the bone (such
a screw is known as a perfect screw). Again, once the requirement
for neutralization (one mini-screw) is satisfied, the remaining
mini-screws may be inserted in the compression mode. If they neutralize
as well, so much the better.
Mini-plates are almost always essential for unstable comminuted
metacarpal fractures (Fig. 8) and metacarpal fractures with bone
loss. Multiple displaced metacarpal fractures (Fig. 9) are usually
unstable and require closed or open internal fixation.
An axial load resulting from impact against a clenched fist causes
most subcapital or metacarpal neck fractures (boxer fractures).
The fifth metacarpal is most commonly injured, followed by the fourth
metacarpal. Rotational and lateral deviation deformities should
be corrected. Shortening may occur as a result of impaction, angulation,
or a combination of the two. There is some latitude for acceptance
of dorsal angulation. As noted above, in general, dorsal angulation
of as much as 10° more than the amount of motion in the respective
carpometacarpal joint may be accepted. Consequently, up to 15° of
dorsal angulation may be accepted in the second and third metacarpals.
Subcapital fractures with as much as 50° of dorsal angulation in
the fourth metacarpal and 70° in the fifth metacarpal have healed
without pain or subjective functional deficit, although with varying degrees
of cosmetic deformity49-51. A
functional deficit may also be masked by low demand. The greater
the dorsal angulation upon presentation, the more likely that there
is an injury to an adjacent metacarpal at the carpometacarpal joint
in the form of a fracture, dislocation, or a combination
of the two27. Consequently, it
is important to survey these areas for coexisting injury during
physical examination and when viewing radiographs.
Although we have detailed the extremes of acceptable parameters,
if a fracture approaches or exceeds these limitations and is seen
early enough that reduction can be achieved, an effort to achieve
anatomical or near-anatomical reduction should be undertaken. The
coexistence of clawing, apparent angular deformity, malrotation,
or any obstruction of digital motion makes fracture reduction even more
compelling. The Jahss maneuver is an effective reduction method52. In this maneuver, the metacarpophalangeal
joint is flexed 70° to 90°. The proximal fragment is compressed
in a palmar direction by the physician’s fingers while the
physician’s thumb applies dorsally directed axial pressure to
the metacarpal head through the proximal phalanx. When a reduced
fracture is unstable, any of a number of transcutaneous Kirschner-wire
applications is effective for splinting the site until callus is
visualized on a radiograph. In the rare case when open reduction
is needed, Kirschner wires may still be used just as with closed
reduction. More secure fixation may provide the advantage of allowing earlier
and more intensive rehabilitation with no additional soft-tissue
dissection other than that necessary for the open reduction itself.
Mini-condylar plates are ideal in terms of both size and design47,48. They also have a lower profile than
mini-T, mini-L, or angled plates, and they are more versatile in
that they may be applied dorsally on any metacarpal and laterally
on the metacarpals of the thumb, the index finger, and the small
finger.
Fractures of the metacarpal base of a finger are generally stable, but
even minor rotational malalignments at this level are greatly magnified
at the fingertips and may interfere with function. These fractures
are easily missed at the time of initial evaluation because of poor-quality
radiographs or poor positioning. Treatment of an extra-articular fracture
of the metacarpal base is similar to that of a fracture of the shaft.
Mini-condylar plates are more adaptive than straight plates in the
region of the metaphyseal-diaphyseal junction. Displaced articular
fractures are reduced and stabilized with Kirschner wires or mini-lag
screws.
An intra-articular fracture of the metacarpal base of a finger
may be unicondylar (a reverse Bennett fracture) or comminuted. Displaced
unicondylar and bicondylar fractures are reduced and stabilized
with pins, screws, metaphyseal plates, or a combination of these
implants. Subluxated and dislocated carpometacarpal joints must
be reduced and incorporated into the fixation.
Intra-articular fractures of the metacarpal head of the fingers and
thumb are treated similarly53.
A condylar fracture of the metacarpal head may be associated with
a complex metacarpophalangeal joint dislocation. This fracture is
usually on the ulnar side of the metacarpal head when the complex
dislocation occurs in a finger. Whenever an articular fracture is
treated with open reduction, great care should be taken to preserve
soft-tissue attachments to the articular fragments to preserve their
blood supply.
Although the forces acting to displace phalangeal fractures and metacarpal
shaft fractures of the thumb may differ from those acting on the
fingers, fractures of the thumb may be evaluated and treated similarly.
The metacarpal of the thumb has no suspensory protection from shortening after
fracture but is quite tolerant of this component of deformity. When
intra-articular or extra-articular fractures of the base of the
thumb metacarpal are unstable, the abductor pollicis longus and
the adductor pollicis shorten the thumb and the adductor pollicis
adducts the thumb. This narrows the thumb web space and results
in a decreased span of grasp with accompanying limitations of pinch
and grip. This may seriously limit hand function.
With an extra-articular fracture of the thumb metacarpal base,
an adduction deformity of up to 30° is acceptable because of the compensatory
capacity of the trapeziometacarpal joint, but greater deformity
should usually be corrected79,80.
A reduction should be performed for deformities accompanied by compensatory hyperextension
of the metacarpophalangeal joint. Successful closed reduction may
be stabilized with transcutaneous Kirschner wires. If open reduction
is necessary, metaphyseal mini-fragment plates such as the mini-condylar,
mini-T, or mini-L plates are appropriate for application.
An axial force along a partially flexed thumb may produce an articular
fracture of the metacarpal base. This is termed a Bennett fracture
and is distinguished by a nondisplaced palmar radial fragment attached
to the anterior oblique ligament and by dorsal, radial, and proximal
displacement of the base of the shaft caused by the unopposed pull
of the abductor pollicis longus. The distal part of the metacarpal
is adducted, and the thumb web space is narrowed by the adductor
pollicis. Most surgeons strive to reestablish articular congruity in
a fresh Bennett fracture by closed reduction. Reliable fixation
of this inherently unstable fracture is achieved with Kirschner
wires. Deformity is concurrently corrected. This fracture is especially
suited for exchange of a Kirschner wire for one or more mini-lag
screws, thus enhancing the stability of the construct (Fig. 13). While symptomatic
posttraumatic arthritis does not always correlate with articular
incongruity, minimally traumatic restitution of the joint surface
and normal joint mechanics appears to be the most reliable deterrent3,4,81,82. Open reduction is rarely
necessary or indicated. When a Bennett fracture that is detected more
than two to three weeks after injury is solid or cannot be completely
reduced by closed manipulation, an allowance for a small amount
of joint step-off may be preferable to the operative trauma necessary
to restore joint congruity.
Comminuted fractures of the base of the metacarpal of the thumb
are caused by mechanisms similar to those that cause a Bennett fracture
but with higher energy. A Rolando fracture is a T or Y-shaped intra-articular
fracture of the base of the metacarpal of the thumb that has two
major articular fragments. The deformity is similar to that occurring
after a Bennett fracture. Closed reduction with use of ligamentotaxis
and periosteotaxis is often possible by application of distal traction
to the thumb. Temporary transcutaneous Kirschner-wire fixation may
adequately stabilize this fracture during healing83 (Fig. 14). More highly
comminuted fractures may require mini-external fixation
or traction to reestablish and maintain congruity of the shattered
base of the metacarpal of the thumb84.
Larger fragments may be incorporated into the construct with Kirschner
wires in most instances; occasionally, however, mini-screws are
used. Compacted cancellous bone may be added if there are defects,
which produce instability.
Stiffness resulting from tendon adhesions and joint contractures is
the most common complication associated with hand fractures2,14. Stiffness has been shown to be directly
correlated with the severity of the initial fracture, the presence
and severity of soft-tissue injury, excessive immobilization (more
than four weeks), and the extent of operative dissection necessary
for mini-plate application5,14,87.
Conversely, fractures that require mini-plate fixation but are treated
without fixation or with inadequate fixation still lead to stiffness
and are associated with an increased rate of nonunion and malunion21,60. Immobilization in inappropriate positions
and an inadequate rehabilitation program may also contribute to
stiffness.
Chronic pain is rarely a compelling long-term problem following
hand fractures, even in the event of posttraumatic arthritis2-4. Occasionally, however, arthroplasty
or arthrodesis is indicated and may improve function as well as
relieve pain76-79.
Malunion and nonunion are more likely to occur at the site of unstable
fractures that are inadequately reduced, poorly stabilized, and
not treated with bone-grafting than they are at the site of those
that are treated with adequate reduction, stable fixation, and bone-grafting
of defects21,60. Adjacent joint
stiffness and tendon adhesions are common. If malunion or nonunion
is sufficiently symptomatic, operative reconstruction is indicated
(Fig. 15).
One must go back to the fundamentals of fracture treatment and start
anew. Anatomical correction of deformity, sufficient stability to
allow simultaneous bone-healing and digital rehabilitation, respect
for soft-tissue and vascular integrity, pain control, and early
intensive rehabilitation are required. Mini-plate fixation is usually
the most reliable method of stabilizing these reconstructed fractures
while they heal. Corrective osteotomies are performed for malunions, and
some of these may require bone-grafting. A nonunion often requires
compression, bone-grafting, or both. Tenolysis, capsulotomy, or
both may be done concurrently if aggressive rehabilitation can begin
immediately after surgery or independently at a later time.
Botte et al., in a review in which 422 pins were used to stabilize hand
and wrist fractures in 137 patients, reported thirty-four complications
involving forty-five pins (11%) in twenty-four patients
(18%)93. Sixty-nine percent
of the complications, which included infection, pin-loosening, loss
of reduction, symptomatic nonunion, and impaled extensor and flexor
tendons, occurred in the phalanges. Poor initial pin placement and
patient noncompliance correlated most highly with these complications.
In most cases of poor pin placement, the problem was not discovered
until after surgery. Therefore, pin placement should be confirmed
by radiographs at the time of surgery. Care of the skin surrounding
the pins and removal of the pins as soon as bone-healing (radiographic
evidence of callus) allows (usually three to six weeks after insertion)
eliminates much of the risk of pin-loosening and pin-track infection.
The complication rate associated with mini-plate fixation has been
reported to be 67% (six of nine) when phalangeal fractures were
involved and 34% (ten of twenty-nine) when metacarpal shaft
fractures were involved14,94.
Stiffness was the most common complication. The soft-tissue dissection
necessary for mini-plate application and the interference with tendon
excursion were the main causes. Twenty-five percent of the mini-plates
were removed because of discomfort or stiffness. The smaller lower-profile
mini-plates that are currently available may provide better results.
Kirschner wires are almost always used for temporary fixation
and are removed after the early appearance of fracture callus on
radiographs. Mini-screws and plates are usually only removed for
cause. Reasons for removal may include prominence and irritation
under the skin, loosening, pull-out, or breakage. Loosening or breakage may
herald delayed union, nonunion, or malunion. Implants may also be
removed at the time of tenolysis or capsulotomy.