Several modalities of treatment are currently available for
the management of diaphyseal humeral fractures. A long arm cast,
a functional brace, an external fixator, a compression plate, and
an intramedullary rod are different devices used to achieve the
same ultimate results, but the biological mechanisms through which
they accomplish this vary. Each one of these devices has a place
in the management of humeral shaft fractures, and no one treatment
is superior under all circumstances.
Understanding how the fracture heals with each form of treatment
is essential for selection of the most appropriate choice for any
specific fracture. It is the responsibility of the treating physician
to understand the appropriate indications for each treatment modality,
to recognize the biological and technical aspects that underlie
its usage, to appreciate the importance of any residual deviation
from normal as well as harmful sequelae, and to be familiar with
all possible complications and their management. The present article describes
the four most commonly used treatments: a functional brace, an external
fixator, a plate and screws, and an intramedullary rod. An outline
of the biological mechanisms of fracture repair with each of the four
methods of treatment is included.
Fracture Motion
Two types of motion occur at the fracture site: elastic motion
and plastic motion. Elastic motion is a displacement of the bone
fragments that is completely reversed after the load is relaxed.
This motion is acceptable and allows healing with satisfactory alignment.
Plastic motion is a displacement of the bone fragments that is not
reversed after the load is relaxed, resulting in a change in the
position of the fracture fragment. This motion is not acceptable.
It may lead to nonunion, and, even if union occurs, malalignment
is present.
Elastic motion with rigid fixation (plate-and-screw fixation)
allows motion in the order of micrometers at the fracture site under
normal loading conditions1. With
this degree of motion, the medullary circulation is reestablished
rapidly. In areas of contact, cutting cones of bone-remodeling may
cross the fracture site directly and the fracture heals with direct
formation of new bone on the original bone with little or no external
callus2. The strength of the healing bone
reaches a peak within a few months (about eight weeks in dogs),
and the strength of the bone with a plate is approximately the same
as that of the intact bone during the early stage of healing, but
the underlying bone does not reach its original strength and even
loses strength over the next few months due to cancellization of
the cortical bone beneath the plate3-5.
This change from dense cortical bone to cancellous-like bone may
be due to stress protection provided by the plate, to a change in
the blood supply caused by the surgical procedure, or to a combination
of the two. New procedures and devices have been designed to reduce
the compromise to the blood supply, to minimize the stress protection, and
to improve the long-term effects on the healing bone. The full strength
of the bone with the plate in place is not reestablished for approximately
two years6.
With the less rigid forms of fixation (intramedullary rods without locking,
external fixators, casts, and braces), the elastic motion at the
fracture site is at least 1 mm and can be as much as 1 cm with normal
activities. When there is displacement between the fracture fragments
or motion of more than a few micrometers at the fracture site, the
medullary blood vessels cannot cross the fracture site until the
fragments have been connected and immobilized by callus7.
With rigid fixation, the neovascularity necessary for fracture-healing
comes principally from the medullary circulation8.
With less rigid fixation systems, the surrounding soft tissue provides
almost all of the neovascularity to the callus bridging the fracture
site. With less rigid fixation, early muscle activity and the resulting
localized inflammatory response are important for early bone formation.
It is important to understand how these types of callus form and how
they can provide adequate strength to resist plastic deformation
while allowing elastic motion during normal functional activities.
With rigid fixation, the early bone forms primarily in the microscopic
gaps between the bone ends, with occasional direct osteon-to-osteon
new-bone formation at the contact points. This new bone is mostly
shielded from the normal stress of functional activities because
of the mechanical properties of the plate-and-screw fixation. This
is why the strength of the bone at the fracture site for the first
few months after plate removal is only about one-half of the strength
of the original bone3,4. The new
bone remodels and normal strength returns only after the plate is
removed and normal stresses are applied. With less rigid fixation,
new bone is formed on the surface of the bone adjacent to the fracture
and, until this periosteal callus bridges the fracture site to immobilize
the fracture, it is in a stage of instability7.
Initially, a soft callus is formed.
Radiographically, the callus shows no evidence of bridging bone
because the tissues bridging the fracture site are composed of hematoma,
cartilage, and fibrous tissue and are not yet mineralized. A dense
fibrous layer forms in the most peripheral portion of the bridging
callus with well-oriented collagen fibers guided by early stresses. Beneath
this layer is a wedge of cartilage (Figs. 1-A and 1-B). This construct of callus bridging
the fracture fragments acts mechanically much like the intervertebral
disc, allowing a strong yet compliant connection between the bone
segments. The dense, well-oriented collagen-fiber layer acts like
the anulus fibrosus, providing tensile resistance to bending and
torsion. The centrally confined cartilage acts like the nucleus
pulposus, providing a hydraulic-like compression resistance for
load transfer. Although this soft callus is relatively strong, it
is vulnerable to painless creep with deformation under static loading,
such as that which occurs when leaning on the arm9.
Within a few weeks, the peripheral callus begins to mature. The peripheral
portion of the bridging callus just beneath the soft tissues surrounding
the bone begins to mineralize7 (Fig. 2). Thus, the
first portion of the bridging callus to ossify is the farthest from
the neutral axis. Bone in this location has a mechanical advantage
compared with bone near the neutral axis because its resistance
to bending and torsion is proportional to the fourth power of the
diameter of the callus. This means that a callus twice as wide as
another callus is sixteen times more effective at resisting bending
and torsion. A wide bridging callus can make the site of the healing fracture
quite strong, and yet the fracture gap may be visible on the radiograph
even when the bone has regained its strength (Fig. 2). In a rat model
of femoral fracture-healing, this occurred at about five weeks7. As the fracture consolidates and the
callus remodels, the callus does not become stronger but the fracture
line fills with bone, the peripheral callus shrinks, and the medullary
canal is reconstituted.
Fracture Stability
Fracture stability is reflected by the degree of plastic motion
or progressive deformity that can occur at the fracture site. It relates
to the strength of fixation of the fracture. The basic parameters
that determine fracture stability are coaptation, compression, neutralization,
and a tension band with a buttress. Each of these factors must be addressed
with each fracture-fixation method.
Accurate coaptation of the fracture fragments is important with rigid
internal fixation because good bone contact is required for both
strength and rigidity. With less rigid fixation, accuracy of coaptation
is important only for cosmetic appearance and function. Coaptation
is achieved at surgery by direct repositioning of the fragments.
With functional bracing, gravity alignment and early function provide
coaptation.
Compression of the fracture surfaces helps to provide stability
as well as to apply strains to the healing tissues to guide their alignment.
With rigid internal fixation, compression can be applied passively
with the hardware at the time of surgery. With less rigid fixation
and especially with functional bracing, muscle activity provides
active compression at the fracture site.
Neutralization refers to the forces applied to the fracture that balance
the forces displacing it. Without adequate neutralization, the fracture
deforms plastically and fixation is lost. Neutralization with rigid
plate-and-screw fixation requires at least eight cortices of screw
fixation through the plate on each side of a fracture of the humerus.
Less fixation may lead to screw pull-out and separation of the plate from
the bone. Neutralization with intramedullary nails is provided by
one of two mechanisms. If a length of the medullary canal that is
2.5 times the diameter of the humerus can be reamed for a tight
fit of the nail in one of the fragments, and there is cortical contact
at the fracture site, the neutralization for that fragment is generally
adequate to resist angulation and rotation. If the fragment is short
and the length of the tight fit is <2.5 times the diameter,
neutralization must be achieved by additional fixation. With most
systems, transcortical screws are used through the proximal or distal
end of the nail. Other devices deploy some sort of intramedullary
cancellous fixation mechanism such as blades, pins, and so on. If
there is a gap at the fracture site, these same mechanisms are necessary
to maintain length and rotational alignment.
Although the most rigid, strong, and visible components in a
typical external fixator construct are the connectors joining the
pins between the bone fragments, the parameters that control neutralization
of the fracture are more related to the pins. The pin parameters
over which the surgeon has control include diameter, material, separation,
and span. Plastic and elastic bending of the pins is responsible
for most of the fracture-site movement. Plastic bending resistance is
proportional to the area moment of inertia of the pin’s cross
section (the fourth power of the diameter). Elastic deformation
of the pins contributes to pin-loosening, and pin-loosening is the
most common mode of loss of neutralization associated with external
fixation of humeral fractures. The elastic bending resistance of
a 5.0-mm pin is 2.5 times greater than that of a 4.0-mm pin of the
same material. The strength of the pin in bending is related to
the third power of the diameter; thus, the ability of a 5.0-mm pin
to transmit bending without plastic deformation is twice that of
a 4.0-mm pin of the same material. Pin strength is also affected
by pin material. The stiffness of a stainless-steel pin is almost
twice that of a titanium pin of the same diameter. Pin span is the
distance between the pin-bone interface and the pin-clamp interface,
or the "free span" of the pin between its connections.
The neutralization of any construct is inversely proportional to
the square of the pin spans in the construct. The closer the pin clamps
can be placed to the skin, the stronger and more rigid the fixation.
Pin separation is the distance between any two pins within the same
bone fragment. This distance provides the leverage by the pin cluster
to resist angulation of that fragment in the plane of those pins.
Thus, pins that are widely separated and are not all in the same
plane improve the neutralization, or strength and rigidity of hold,
for the construct on that fragment. Placing a third pin (or more)
out of the plane of the first two pins substantially reduces the
bending of all of the pins and thus their tendency to loosen.
Neutralization with a functional brace is accomplished primarily by
soft-tissue compression. Circumferential wrapping of the soft tissue
with any material that can be closely fit to the shape of the arm
and can be adjusted to maintain compression of the tissue throughout
the period of treatment provides the neutralization required for
early functional activities. The hardness and rigidity of the material
is not important mechanically7,9;
only the ability of the device to be adjusted to maintain soft-tissue
compression and suspension of the system is important. Thus, many
soft, compliant, and comfortable materials can be used successfully.
Soft cast materials or thermoplastics applied directly to the patient’s
arm with custom-fit or compliant prefabricated braces are more comfortable
than rigid, hard, or thick thermoplastic sheets or plaster. Comfort
is important for the early introduction of functional activities.
Tension-band systems resist bending by having a buttress, or compression-resistant
area, on the concave side of the bend. The distance of the buttress
from the line of action of the tension band provides the leverage.
This distance and the strength and rigidity of the tension band
determine the strength and rigidity of the fixation.
With plate-and-screw fixation, the tension band is the plate. Thus,
the tension is both rigid and strong. The buttress is the contact
of the bone fragments beneath the plate, with the maximum leverage
related to the diameter of the bone. Since there is a tension band
on only one side of the bone, the plate should be placed on the
convex (tension) side of the bone. For the humerus, this is lateral
since the most common tendency is for varus angulation of the fracture9. Bending in any other plane is resisted
mostly by the bending resistance of the plate only.
With intramedullary fixation, the tension band is the nail. The
buttress is the fracture-surface contact on the concave side of
the bend, with a lever arm of about one cortical thickness from
the nail. Thus, in a noncomminuted fracture, a buttress is available
on all sides to resist bending in all planes.
An external fixator acts as a tension band only when there is bone
contact to provide a buttress. The fixator provides excellent leverage
only in the direction of its placement. If placed laterally, it
resists varus angulation; if placed anteriorly, it resists anterior
bowing. In all other planes, the resistance is related to the bending
resistance of the frame only.
With functional bracing, the tension bands are compliant and
are provided by the soft tissues9.
The buttress is provided by bone contact or callus. Both the buttress
and the tension bands in the upper arm are symmetrical and provide
resistance in all planes of angulation with compliant but strong
resistance to bending.
The role of open treatment of fractures of the humerus remains controversial.
Routine surgical management of humeral shaft fractures is probably
not appropriate since the results of nonoperative treatment are
generally satisfactory; acceptable alignment and healing occur in
at least 90% of patients managed nonoperatively10-12.
The generally accepted indications for surgical treatment are
a type-III open fracture; polytrauma with substantial chest and/or
head injury; an ipsilateral fracture of both bones of the forearm
(floating elbow); and extensive local associated injury involving
the joint, brachial plexus, muscle, or tendon.
If open treatment is required, the choice of implants includes plates
and screws, intramedullary nails (with or without reaming and with
or without locking), or external fixators13.
External fixation is indicated only for open fractures with extensive
bone loss or when extensive comminution precludes the use of internal
fixation14.
Plate Fixation
Most surgeons favor an extensile anterolateral approach for exposure
of the humerus. This exposure has the advantage of allowing the
radial nerve to be visualized and protected15.
An alternative approach is through the posterior aspect of the arm
with splitting of the triceps. Fractures of the distal aspect of
the humeral diaphysis can be exposed through a posterior approach16,17.
Plate fixation requires accurate reduction of the major fracture fragments18. For comminuted fractures that cannot
be reduced anatomically, bridge-plating techniques may be used18. Fractures that have large comminuted
fragments or oblique spiral fractures should be reduced anatomically
with lag-screw fixation, followed by plate fixation4,18,19. A broad plate with staggered holes
is recommended. With the staggered holes, there is no possibility
of crack propagation from the fracture site into adjacent screw-holes18. It is essential that adequate purchase
of the screws be achieved on both sides of the fracture20. A minimum of six and preferably
eight cortices on both sides of the fracture should be engaged by
the screws (Figs. 3-A, 3-B, and 3-C). The radial nerve must be protected
throughout the entire surgical procedure.
Plate fixation of open fractures of the humerus require the same general
principles of treatment as those applied to open fractures elsewhere
in the skeleton. These include meticulous wound débridement,
fracture stabilization, appropriate soft-tissue management, and
use of prophylactic antibiotics21,22.
Once the wound has been appropriately debrided, routine plate fixation
is done with particular attention paid to obtaining rigid fixation.
Unless the wound is anterolateral, it is best not to apply the plate
through the traumatic wound. Instead, after wound débridement,
a formal anterolateral approach to the humerus should be used.
There are a number of arguments for primary surgical fixation
of humeral fractures in a patient with polytrauma22,23.
Most closed methods of treatment depend on the patient being upright,
allowing the weight of the arm to contribute to fracture stabilization.
In a patient in the recumbent position, it is difficult to control
the fracture with closed treatment. In addition, patients with concomitant
chest injury are poor candidates for the use of a sling and swath.
In such circumstances, plate fixation is an option for stabilization
of the fracture without interfering with the general treatment of
the patient. Rigid internal fixation should be obtained so that
the extremity does not require protection from movement and the patient
can be mobilized early.
Concomitant fractures of the humerus and both bones of the forearm
occur in a small percentage of patients, and most are associated
with extensive soft-tissue injury24.
Early mobilization of the elbow helps to maintain elbow function,
and the forearm fractures accompanying such extensive skeletal injury
usually are treated with internal fixation. Therefore, in most situations,
primary internal stabilization of the humerus is indicated. Internal fixation
of the humerus should be performed at the same time as internal
fixation of the radius and ulna.
Fractures of the humerus associated with dislocation of the glenohumeral
joint or dislocation of the elbow pose a difficult treatment problem.
Early mobilization of the injured joint after reduction is important
for optimal rehabilitation of the joint and a maximum useful range
of motion. Mobilization usually requires the humerus to be stable.
Rigid plate fixation provides stability to the humerus so that the
injured joint can be properly treated.
A radial nerve palsy sustained concomitantly with a humeral fracture
is not an indication for exploration of the nerve or for internal
fixation of the fracture. Conversely, when a radial nerve palsy
develops while the fracture is being reduced, the radial nerve should
be explored. Whenever the nerve is explored and the humerus is not
healed, internal fixation of the humerus is recommended. In addition,
patients with associated brachial plexus injury should have internal
fixation25. Stabilization of the
humerus in this case permits earlier rehabilitation of the injured
extremity and shortens the hospital stay.
A patient with a humeral shaft fracture and a lower limb injury who
requires crutches or a walker in order to walk is usually mobilized
more quickly after surgical stabilization of the upper limb injury.
An axially stable fixation with supplementary fixation with a plaster
cast or a brace permits some weight to be taken through the volar
surface of the forearm and the medial aspect of the arm. Transverse fractures
or spiral fractures with anatomic reduction and good lag-screw fixation
are best suited for plate fixation and for shared weight-bearing.
Internal fixation of one or both humeral fractures with a plate
and screws is recommended for a patient who has sustained a bilateral
humeral fracture26. Self-care
is improved, and the patient can be independent.
Impending or established pathological fracture due to metastatic cancer
is a well-recognized indication for surgical treatment27. The use of plate fixation in these
circumstances permits active use of the limb as well as direct treatment
of the metastatic lesion by curettage. Supplemental methylmethacrylate
may be needed to improve the fixation of the screws to the bone.
Intramedullary fixators can be used, but they do not allow removal
of the metastatic deposits. Removal of the metastatic deposits is
not always recommended, but it occasionally is necessary. If intramedullary
fixators are used for a pathological fracture due to metastatic
cancer, the fixation should be rigid.
Segmental fractures occasionally are best treated with internal fixation.
The location of the segmental fractures is an important factor in
the selection of the most appropriate type of fixation. Intramedullary
fixation is not effective for fractures in the proximal or distal
quarter of the humerus; when associated with a diaphyseal fracture,
these segmental injuries are best treated by plate fixation. Fractures occurring
in the proximal and distal quarters without an intervening diaphyseal
fracture should be treated separately. They are exposed through
separate incisions and fixed with separate plates28.
Segmental fractures confined to the middle half of the humerus are
ideal for intramedullary nail fixation21,29-31.
The ability to achieve a satisfactory closed reduction of both fractures
is a prerequisite for the use of intramedullary fixators and, if
such a reduction cannot be obtained, plate fixation is a better
option32.
The final indication for internal fixation is failure of closed
treatment, which includes the inability to obtain or maintain a satisfactory
closed reduction, the inability of the patient to tolerate external
splinting, and a delayed union or nonunion33.
Closed treatment of a transverse fracture with a gap often fails because
the gap increases as a result of the distraction of the fracture
fragments by the weight of the arm11,12.
Closed treatment also often fails in obese patients22 or in women with large breasts because
the arm cannot be brought to the side without angulating the fracture.
Furthermore, in obese patients the plaster irritates the skin in
the axilla. Under these circumstances, early recognition of the
failure of the closed treatment and subsequent surgical treatment
are recommended. Plate fixation is preferred for these patients.
A full discussion of delayed union and nonunion of the humerus
is beyond the scope of this article5,11,21,34,35;
however, for patients in whom union has not been obtained by twelve
to sixteen weeks after good closed treatment, surgical intervention
should be considered. Direct exposure of the fracture site with
careful protection of the radial nerve, rigid fixation, and onlay
circumferential cancellous bone-grafting will result in satisfactory
healing in the majority of these patients36.
The best reason to use a plate is that it allows control of the
fracture. With use of a plate and screws, the rotation, length,
and angulation of the humeral diaphysis are controlled. The quality
of reduction is better with a plate and screws than with other methods
of surgical treatment. The use of a plate allows injury to the adjacent
joints to be avoided, and it minimizes morbidity, particularly that
related to the shoulder. Plate fixation does require a wide surgical
exposure. Exposing the fracture, obtaining the reduction, and securing
the fixation require more time than that needed for intramedullary fixation.
There is an increased prevalence of nerve injury and a relatively
high prevalence of failure of fixation in patients in whom the quality
of the bone is not ideal, particularly in those with extensive comminution
or osteopenia.
Randomized, controlled trials comparing plate fixation with intramedullary
fixators have produced contradictory results19,30,37-40.
Both techniques, if performed properly, provide satisfactory outcomes
for the majority of patients39.
The question for the surgeon is which technique is the most effective
in his or her hands for the management of a particular fracture
pattern. Another consideration is that a nonunion after treatment
with intramedullary nailing poses a more difficult problem than
does nonunion after plate fixation41,42.
Therefore, plate fixation often remains the primary choice for patients
in whom surgical fixation is thought to be appropriate.
Intramedullary Nailing
Flexible or semirigid pins, usually several of them, can be used for
intramedullary fixation. The operation can be done with the patient
in the supine, lateral decubitus, or beach-chair position. A closed
reduction is done and confirmed with use of image intensification.
For antegrade insertion, an incision is made over the greater tuberosity
of the humerus with splitting of the proximal portion of the deltoid muscle.
The greater tuberosity is palpated, and a drill-hole of appropriate
diameter is made at the insertion of the rotator cuff on the greater
tuberosity. A flexible nail, such as an Ender nail, of appropriate
length and diameter is then introduced through this drill-hole into
the proximal fragment and is directed distally, under image intensification,
to the fracture site43. With the
fracture reduced, the nail is advanced across the fracture site
into the distal fragment. A stiffer, straight, or slightly bent nail
such as a Rush rod may also be used. Rush rods have a tendency to
displace the distal fragment into varus alignment as the rod is
inserted across the fracture site. This should be avoided. It is possible
to insert two or more small-diameter rods across the fracture. Rotational
stability is improved by using different insertion points in the
proximal portion of the humerus and by spreading the rods in the
distal fragment. These types of intramedullary fixation are usually
supplemented by some form of external immobilization in order to
control rotation at the fracture site.
Problems associated with this technique include limited rotational
stability, inability to control shortening of the humerus, and interference
with shoulder function as a result of rotator cuff impingement or
subacromial impingement of proximally migrated pins. Although the
lack of rotational stability may be compensated for by use of external
immobilization, shortening cannot be addressed by external immobilization.
With shortening, proximal pin migration may occur with a subsequent
increase in shoulder problems.
Fixation by means of retrograde pin insertion has been used to avoid
problems around the shoulder that occur as a result of antegrade
pin insertion26,44. Small-diameter
flexible pins are recommended for this technique45,46.
The patient is positioned in the supine or lateral decubitus position.
With the arm prepared and draped free, a midline incision is made
over the posterior aspect of the distal part of the humerus. The
muscle fibers of the triceps are split longitudinally, exposing the
humerus just proximal to the olecranon fossa. A window approximately
1 cm wide and 3 cm long is made in the posterior cortex of the humerus,
beginning just proximal to the olecranon fossa, and the nails are
inserted in a retrograde fashion, crossing the fracture site and
continuing into the proximal portion of the humerus. Use of an image
intensifier is essential for this technique to be carried out safely
and expeditiously47.
Problems with retrograde nail insertion include difficult access to
the narrow medullary canal in the distal part of the humerus, irritation
of the triceps by pin prominence, a decreased range of motion of
the elbow, and fracture at the level of the nail insertion site48.
Intramedullary fixation with a larger device allowing proximal and
distal locking has been developed. This concept is attractive because
the problems of maintenance of length and control of rotation can
be overcome. However, initial efforts have met with a number of
problems49,50. The nails were
straight, necessitating a relatively medial insertion point for
antegrade nailing. This medial insertion point interfered both with
the rotator cuff and with the articular surface of the humerus.
The increased diameter of the nail, which was necessary to obtain
locking, led to a considerably larger entry portal in the proximal
portion of the humerus, contributing to the postoperative problems
associated with shoulder function33.
Distal locking was also a problem with early versions of these intramedullary
nails. The use of an expansion bolt to deploy fins on the distal
end of the nail proved to be inadequate to control rotation in many
patients32; side-to-side locking
is impractical by virtue of the shape of the distal part of the
humerus21 (which also precludes
effective intramedullary reaming into the metaphysis of the distal
fragment). This necessitated anteroposterior locking with an attendant
risk to the neurovascular structures in the front of the arm as
well as interference with the biceps and brachialis muscles51. In later designs, the nails have had
a smaller diameter with smaller locking screws and have permitted
the use of multidirectional locking screws in the proximal fragment
to avoid the possibility of iatrogenic injury to the axillary nerve52.
The success of intramedullary nailing of the humerus should be measured
by both fracture union and functional outcome. However, reports
in the literature have been contradictory, and few have directly
compared intramedullary nail fixation with other forms of fracture
treatment. In reports in which plate fixation has been directly
compared with intramedullary fixation, the rate of complications
associated with locked intramedullary nails has appeared to be higher
than that associated with plate fixation19.
The increase in complications after intramedullary nailing appears
to be related primarily to the rates of union, which are somewhat
lower than those after plate fixation, and to a substantial increase
in functional symptoms, such as shoulder pain and stiffness52,53. Complications such as radial nerve
palsy, infection, delayed union, and failure of fixation appear
to occur at a similar rate after both types of fixation.
The indications for nailing are limited. Intramedullary nail
fixation has a place in the management of pathological fractures
of the humerus, particularly if there is more than one metastatic deposit
within the bone38,54,55. It is
also useful in the management of comminuted and segmental humeral
shaft fractures that require operative treatment.
The principle behind functional bracing of humeral fractures
is that, in most patients, gravity results in adequate alignment
of the fractured bone and physiologically induced motion at the fracture
site promotes osteogenesis56-62.
Functional braces do not immobilize the fracture; they simply stiffen
the upper arm through soft-tissue compression. The orthopaedic community
has long recognized that stabilization of humeral diaphyseal fractures
in a cast results in union in the vast majority of patients. The
hanging cast and coaptation splint, which have been popular for
several decades, are the methods of choice of most orthopaedists. Functional
bracing often fails to restoreanatomical alignment of fracture fragments,
and varus angulation after healing is common. However, the angulation
is, in almost all instances, cosmetically and functionally acceptable7,58-63. The high prevalence of union57,60,63-66 and the avoidance of infection, which
can occur after surgery, imply an earlier return to the activities
of daily living and a lower overall cost of care.
The fact that functional bracing does not immobilize the joints adjacent
to the fracture makes early restoration of motion possible. Rotatory
deformities are also rarely encountered perhaps because of the corrective
effect of muscular forces associated with the early introduction
of function60. As is true with
all methods of treatment, functional bracing is not applicable to
all diaphyseal humeral fractures. The method has its appropriate
indications, and the management protocol requires a clear understanding
by the treating physician as well as the cooperation of the patient.
Functional bracing requires that the patient be able to stand
or sit erect. In the absence of gravity acting on the injured extremity, correction
of angular deformities usually is not possible. Conversely, most
isolated closed diaphyseal fractures, regardless of their geometry,
can be treated with functional bracing. However, transverse fractures,
particularly if they are nondisplaced, are the ones most likely
to develop angular deformity. In the case of comminuted or oblique fractures,
the muscle contractions produce desirable positioning at the fracture
site without creating permanent deformity (Figs. 4-A, 4-B, 4-C, 4-D, and 4-E).
The level of the fracture does not influence the ultimate result. Fractures
at various levels heal at the same speed and with similar degrees
of angulation. The fact that the brace does not fully cover every
proximal or distal fragment is irrelevant. As long as the soft tissues
of the extremity are compressed by the adjustable brace and the
arm hangs freely at the side of the body, the desirable environment
for healing is present. The presence of a radial nerve palsy in
association with a closed fracture is not a contraindication to
the use of functional bracing if the palsy appeared concomitantly
with the injury. The probability of spontaneous recovery is very
high57,59,61-63,65. Since the
arm is allowed to hang at the side of the body in a normal fashion,
there is no need to hold the wrist in a cock-up splint. Gravity
brings the wrist into a neutral position and prevents a flexion
contracture of the joint. Active use of the wrist and fingers is
recommended.
Open fractures produced by low-velocity projectiles and associated
with a minimal or moderate degree of soft-tissue damage are usually
good candidates for functional bracing (Figs. 5-A, 5-B, 5-C, 5-D, 5-E, and 5-F). Local cleaning
of the wound and antibiotic prophylaxis are recommended.
Obesity in itself is not a contraindication. Angular deformities
are more severe in obese patients. However, the larger amount of adipose
tissue usually camouflages the deformities effectively (Figs. 6-A, 6-B, 6-C, 6-D, 6-E, and 6-F).
Functional bracing is contraindicated in certain circumstances. Fractures
with axial distraction between the fragments suggest a high degree
of soft-tissue damage. These fractures are more likely to have a
delayed union or nonunion. Surgical stabilization is usually the
treatment of choice. Open fractures with major soft-tissue damage
preclude successful management with functional bracing, particularly
if there is an associated peripheral nerve injury. Other treatment
modalities are more appropriate. Patients with a bilateral humeral
fracture are usually better managed with surgical stabilization
if the treating surgeon has the necessary expertise. Patients with
polytrauma who are unable to walk are best treated by surgical stabilization. Functional
bracing is likely to result in unacceptable angular deformities
in such patients. Fractures associated with vascular injuries that
require surgical repair usually should be internally stabilized.
However, if surgical stabilization is not done at the time that
the injured vessels are surgically repaired, delayed bracing can
be used.
Diaphyseal humeral fractures that are managed with functional bracing
are initially stabilized in a hanging cast or coaptation splint.
As soon as possible after the application of the stabilizing device,
pendulum exercises should be initiated in order to prevent or lessen
long-lasting limitation of motion of the shoulder. Use of a collar
and cuff is essential in order to provide comfort and to prevent
anteroposterior deformity.
The initial cast is removed when the symptoms allow. This may be
as early as a few days or as late as two weeks after application
of the cast. The brace must be adjustable to ensure that the soft
tissues of the arm can be compressed as swelling decreases and atrophy
ensues (Fig. 7).
Frequent tightening of the Velcro straps is necessary during the first
two weeks. Cylindrical sleeves have a tendency to slide distally
and irritate the antecubital space as the circumference of the arm
decreases. The brace should begin approximately 1 in (2.5 cm) distal
to the axilla and should terminate distally 1 in proximal to the
humeral condyles. Supra-acromial and supracondylar humeral extensions
are not necessary. Patients should be able to put the brace on and
take it off easily by themselves.
With the collar and cuff in place, pendulum exercises are continued.
The patient should remove the arm from the sling several times a
day to passively flex and extend the elbow, emphasizing extension
of the joint. Active exercises are started as soon as symptoms allow.
Active abduction and elevation of the shoulder must be avoided because
they may produce angular deformities. Such exercises may be conducted
only after the fracture has become clinically stable. Leaning on
the elbow should be avoided as it is likely to cause varus angulation,
especially of transverse, nondisplaced fractures. Active contraction
of the biceps and triceps assists in correcting the inferior subluxation of
the shoulder that is occasionally seen in patients with a fracture
of the proximal third of the humerus. Most patients fully extend
their elbow one week after the application of the brace. At this
time, the pendulum exercises are continued without the collar and
cuff. Use of the collar and cuff may be discontinued if the patient
wishes. However, use of the collar and cuff during recumbency is
recommended until clinical union of the fracture has taken place.
Use of the brace is permanently discontinued when union of the fracture has
been confirmed on clinical and radiographic examination.
The rate of nonunion reported in the literature in recent years
has ranged from 1% to 5.8%59,62-66.
In one review, the rate of nonunion was 1.5% for closed
fractures, with the brace removed between ten and thirteen weeks, and
5.8% for open fractures61.
All four current modalities of treatment of diaphyseal humeral fractures
have a place in the armamentarium of the orthopaedist. Functional
bracing renders a high rate of union and seems to be a safe method
of treatment for the majority of closed fractures. Type-II and type-III
open fractures seem to respond best to plate fixation or external
fixation, particularly if there are associated neural or vascular pathological
findings. Patients with polytrauma who are unable to walk are also
best treated with plate fixation. Plate fixation is also the best
method of treatment when adequate alignment cannot be obtained with
nonsurgical methods. Intramedullary nailing remains controversial
since its complication rate is higher than that associated with
either plate fixation or functional bracing.
None of the treatments described are a panacea, and complications may
occur with each one of them. An appropriate appreciation of the
biological response to the three modalities; an understanding of
the indications, contraindications, and possible complications of
the treatments; and a mastery of the techniques of application are
essential for the attainment of satisfactory clinical results.