INJURY TO FINGERS
The hand has both
mechanical and sensory functions. Therefore, injuries to the hand not only
disrupt mechanical ability but also compromise the sensory function of the
upper limb. Most hand injuries cause pain, swelling, and often discoloration.
Because the flexor and extensor tendons and the bones lie close to the skin,
each major anatomic structure can be examined easily and its functional status
determined. Radiographs of the whole hand itself are not needed if only the
wrist or finger is injured, but anteroposterior, lateral, and oblique views of
the specific site of injury are essential for a complete evaluation.
Fracture Of Proximal And Middle Phalanges
Diagnosis of fractures of the phalanges requires
anteroposterior, lateral, and oblique radiographs and careful clinical
examination of the soft tissues specifically the flexor and extensor tendons to verify the extent of the injury. Because finger
injuries are often caused by crushing forces, open fractures of the fingers are
common.
Several muscle forces contribute to deformity in
fractures of the proximal or middle phalanx. The insertion of the flexor
digitorum superficialis (sublimis) tendon along the middle phalanx affects the
angulation of a fracture, depending on the location of the break. If the
fracture of the middle phalanx is distal to the insertion of the flexor
digitorum superficialis tendon, the fractured bone angulates volarly. Fractures
proximal to the insertion of the flexor digitorum superficialis tendon angulate
dorsally. In fractures of the proximal phalanx, the insertions of the
interosseous muscle at the base of the proximal phalanx tend to flex the
proximal fragment and the flexor and extensor tendons angulate the fracture
volarly.
For reduction of a fracture of the phalanx, correct
rotational alignment is just as essential as alignment in the anteroposterior
and lateral planes. In the normal hand, the tips of all the flexed fingers
point toward the tuberosity of the scaphoid. Inadequate reduction and
persistent rotational malalignment adversely affect the patient’s ability to
grasp. Often, the rotational malalignment is not noticeable when the fingers
are extended, but it is always obvious when the fingers are flexed. Although
judging the reduction of any phalanx fracture in both flexion and extension may
be difficult, this step is most important.
The high-energy forces that cause transverse and
comminuted fractures of the phalanx often produce significant injury to the
soft tissues of the finger as well. Successful treatment of phalanx fractures
demands careful attention to the potential consequences of the soft tissue injuries. Even though the fracture may
heal in adequate alignment, injuries to the flexor and extensor mechanisms can
lead to significant long-term dysfunction.
Management Of Fracture
Correction of deformity, preservation of motion, and
care of the soft tissues are all important in the treatment of hand injuries. Adherence to the basic principles of
fracture care is essential for good functional results. These principles are
(1) alignment of the distal fragment with the proximal fragment, (2) adequate
immobilization to allow healing, and (3) preservation of motion and soft tissue
function. The primary goal in treating any hand injury is to maintain function,
particularly full active motion of all joints. Persistent stiff-ness in the
interphalangeal and metacarpophalangeal joints and adduction contracture of the thumb produce a functional loss
that can be debilitating.
Immobilization should maintain the hand in a “position
of function”: 45 degrees of extension of wrist, 70 degrees of flexion of the
metacarpophalangeal joint, 20 degrees flexion of the proximal interphalangeal
joints, and maximal abduction of the thumb. If scarring occurs, this position
will preserve as much soft tissue length and joint flexibility as possible. In
any significant hand injury, only fingers requiring immobilization should be
placed in a cast or splinted; the other fingers should remain free to move.
Some fractures of the phalanges are considered stable;
these include most nondisplaced fractures, long spiral fractures, and minimally
displaced intra-articular fractures that do not displace with gentle early
motion. Stable fractures can be treated by taping the injured finger to the
normal adjacent finger (buddy taping) and initiating early active motion.
Frequent and careful follow-up during the healing phase ensures that early
motion does not displace the fracture fragment.
Most displaced fractures of the proximal and middle
phalanges can be treated with closed reduction and cast immobilization using an
ulnar or radial gutter splint. The plaster must be applied with great care to
avoid excessive pressure on the soft tissues, which can cause ulceration of the
skin. The fracture is checked at weekly intervals for 4 to 6 weeks. In
fractures of the phalanges, radiographic evidence of healing appears slowly,
and radiographs do not show union for many weeks. However, most uncomplicated
fractures are clinically stable in 4 to 6 weeks. If examination at that time
detects minimal swelling, no tenderness, and no instability, the patient can
begin gentle protected motion, but the fracture should be protected for an
additional few weeks with
intermittent splinting or buddy taping. Fractures that require open reduction
and internal fixation or closed reduction and pin fixation include unstable
fractures, fractures that cannot be adequately reduced and maintained with
closed means, displaced intra-articular fractures, multiple fractures with soft
tissue injuries, and fractures in patients who repeatedly remove their casts.
Oblique fractures are often unstable and tend to
shorten the finger. Closed reduction under radiographic control followed by
percutaneous pinning restores stability, maintains the reduction, and allows
early motion. Transverse fractures of the proximal or middle phalanx are very
unstable, often requiring internal fixation. Inserted through a dorsal or
midaxial incision, crossed Kirschner wires stabilize the fracture with only
minimal disruption of the soft tissues; the wires are removed under local
anesthesia without significant soft tissue dissection. Small compression plates
may be used.
When a fracture is stabilized with either closed
reduction and pin fixation or open reduction and internal fixation, the finger
is left undisturbed for 8 to 10 days for the initial phase of soft tissue
healing; then active supervised motion is begun to preserve soft tissue
function.
Massive crushing injuries with multiple fractures of
the phalanges and significant destruction of soft tissue require open reduction
and stabilization. Fortunately, the incidence of postoperative infection in open hand fractures is quite
low.
Special Problems In Fracture Of Phalanges
Management of fractures of the phalanges is
complicated by numerous problems. Because of the intricate relationship between
the flexor and extensor tendons, the joints, and the architecture of the phalanges, neglect or inadequate
treatment can lead to significant disability.
Treatment of Oblique Fractures
The pull of the flexor muscles tends to shorten oblique
fractures of the proximal and middle phalanges. Resulting soft tissue adhesions
contribute to stiffness of the proximal interphalangeal joint. In addition, a
bone spike protrudes volarly, creating a mechanical block to full flexion of
the proximal interphalangeal joint. Such problems can be managed in a number of
ways. If the alignment of the proximal phalanx is adequate but joint motion is
limited, the volar spike can be removed surgically and the tendon adhesions
freed. These procedures increase flexion and extension of the proximal
interphalangeal joint. Inadequate bone alignment necessitates osteotomy of the
proximal phalanx and internal fixation with Kirschner wires.
Treatment of Stable Intra-articular Fractures
Most intra-articular fractures of the
metacarpophalangeal joint that have large nondisplaced fragments can be treated
with buddy taping. However, close follow-up is essential to ensure that the
fragment does not subsequently displace.
Treatment of Fracture of Condyles
Intra-articular fractures of the interphalangeal
joints that involve the condyles of the proximal or middle phalanx are usually
unstable. To avoid missing the fractured condyle and to assess the degree of
displacement, radiographic examination must include anteroposterior, lateral,
and oblique views. However, even after adequate open reduction, stable internal fixation, and
fracture healing, stiffness usually persists in the distal or proximal
interphalangeal joint.
Treatment of Malunion and Nonunion
Even with proper treatment and adequate follow-up,
fracture malunion may occur. In most cases, a malunion does not require any
further care, but if it causes pain, limits hand function, or is cosmetically
displeasing, surgical intervention should be considered. Osteotomy at the fracture
site or at an adjacent area of metaphyseal bone is the usual procedure for
realigning the phalanx. The osteotomy is stabilized with an internal fixation
device.
Nonunion is rare in phalanx fractures and often
remains asymptomatic. For symptomatic nonunion, treatment with open reduction and internal fixation combined with bone
grafting usually results in healing.
Treatment of Tendon Adhesions
Because injuries to the phalanges damage soft tissue
as well as bone, adhesions may develop between the flexor and extensor tendons
and the fracture site. The primary clinical sign of this complication is a limitation of active flexion.
The need for assistance to achieve full flexion usually indicates the presence
of adhesions within the sheath of the flexor tendon. Vigorous physical therapy
can help restore motion, but surgical tenolysis of the flexor sheath at the
level of the healed fracture is occasionally required. Extensor tendon
adhesions also limit active finger flexion and require the same treatment.
