Fractures of the Proximal Radius and Ulna

In the embryo, the proximal radius is well defined by 9
weeks of gestation. By 4 years of age, the radial head and neck have
the same contours as in an adult.⁷¹ Ossification of the proximal radius epiphysis begins at approximately 5 years of age as a small, flat nucleus (Fig. 11-1).
This ossific nucleus can originate as a small sphere or it can be
bipartite, which is a normal variation and should not be misinterpreted
as a fracture.¹¹,⁶⁰,⁹⁹

Following a fracture, palpation over the radial head or
neck is painful. The pain is usually increased more with passive
forearm supination and pronation than with elbow flexion and extension.
In a young child, the primary complaint may be wrist pain,²
and pressure over the proximal radius may accentuate this referred
wrist pain. The wrist pain may be secondary to radial shortening and
subsequent distal radioulnar joint dysfunction. The misdirection of
such a presentation reinforces the principle of obtaining radiographs
of both ends of a fractured long bone.

The fracture is usually easy to see on both AP and
lateral radiograph views. Occasionally, oblique views with the forearm
both supinated and pronated will reveal the fracture line clearly.

Some variants in the ossification process can resemble a
fracture. Most of these involve the radial head, although a step-off
also can develop as a normal variant of the metaphysis. There may be a
persistence of the secondary ossification centers of the epiphysis.
Comparison views are useful for evaluation of unusual ossification
centers after an acute elbow injury.

The diagnosis of a partially or completely displaced
fracture of the radial neck may be difficult in children whose radial
head remains unossified. The only clue may be a little irregularity in
the smoothness of the proximal metaphyseal margin (Fig. 11-3). Rokito et al.⁹³
reported complete displacement of the radial head in a 5-year-old male,
in whom the only clue on radiography was a small speck of ossification
in the elbow joint. The full extent of the injury was appreciated when
the radial head was outlined with magnetic resonance imaging (MRI).
Javed et al.⁴¹ suggested considering
an arthrogram to assess the extent of the displacement and the accuracy
of reduction in children with an unossified radial epiphysis (Fig. 11-4).

If the elbow cannot be extended because of pain, special
views are necessary to see the elbow in full AP profile. One view is
taken with the beam perpendicular to the distal humerus, and the other
with the beam perpendicular to the proximal radius. A regular AP view
with the elbow flexed may not show the fracture because of obliquity of
the beam. The perpendicular views show the physeal line of the radius
in clear profile.

With a minimally displaced fracture, the fracture line
may be difficult to see because it is superimposed on the proximal
ulna, and oblique views of the proximal radius may be helpful.¹¹,¹¹⁷ One oblique view that is especially helpful is the radiocapitellar view suggested by Greenspan et al.³⁶,³⁷ and Hall-Craggs et al.³⁸ This view projects the radial head anterior to the coronoid process (Fig. 11-5) and is especially helpful if full supination and pronation views are difficult to obtain because of acute injury (Fig. 11-6).

If the epiphysis is ossified, displacement of the radial
head is usually obvious on a radiograph, but a minimally displaced
fracture is difficult to diagnose before ossification has begun.⁹⁰
The loss of the smoothness of the metaphyseal margin may be the only
finding. Ultrasonography can be used to evaluate for hemarthrosis and
displacement of the fracture and allows a dynamic range-of-motion
evaluation.⁵⁰ The supinator fat pad
is a small layer of fat that overlies the supinator muscle in the
proximal forearm. Displacement of the supinator fat pad may indicate
fracture of the proximal radius.⁹²
The supinator fat pad and distal humeral anterior and posterior fat
pads are not always displaced with occult fractures of the radial neck
or physis.⁴⁰,⁹⁹,⁹⁷

If there is localized tenderness of the radial head and
neck, special studies may be necessary. Arthrography, MRI, and
ultrasound⁵⁰ are options for determining any displacement of the unossified radial head.

To describe head-displaced fractures, Chambers¹⁴ combined the classifications of Jeffrey⁴² and Newman⁷⁰ to produce a new

classification based primarily on the mechanism of injury. The two
subclasses of fractures in group I are valgus injuries and those
associated with elbow dislocations. Valgus injuries are subdivided into
three types based on the location of the fracture line (Fig. 11-7).
Fractures associated with an elbow dislocation are subdivided into two
types. The first is based on the original concept proposed by Jeffrey⁴² that the fracture occurs during spontaneous reduction (Fig. 11-8A). In this case, the radial head lies proximal to the posterior aspect of the joint. The second is based on Newman’s⁷⁰
concept that the fracture and displacement occur during the process of
dislocation of the elbow. In this type, the radial head lies distal to
the anterior portion of the joint (see Fig. 11-8B).
Most radial head fractures in children described in the literature have
been Salter-Harris type IV injuries containing portions of both the
epiphysis and metaphysis, and there is no need to further subclassify
them.

For the neck-displaced fractures, there are two
subgroups: angular and torsional. An angular fracture of the radial
neck may be associated with a proximal ulnar fracture. This association
is recognized as a Monteggia variant.

The final group, stress injuries, includes
osteochondritis of the radial head and physeal injuries of the neck
that produce angular deformities.

Most of these injuries occur in a fall on the outstretched arm with the elbow in extension.³¹,³⁹,⁴²,⁷⁰,⁷¹,¹¹⁷ An associated valgus thrust to the forearm (Fig. 11-9)
compresses the radiocapitellar joint. The cartilaginous head absorbs
the force and transmits it to the weaker physis or metaphysis of the
neck.¹¹⁷ These fractures characteristically produce an angular deformity of the head with the neck (see Fig. 11-9A).
The direction of angulation depends on whether the forearm is in a
supinated, neutral, or pronated position at the time of the fall. Vostal¹¹⁷
showed that in neutral, the pressure is concentrated on the lateral
portion of the head and neck. In supination, the pressure is
concentrated anteriorly, and in pronation it is concentrated
posteriorly.

In two rare types of fractures of the radial neck
associated with elbow dislocation, the head fragment is totally
displaced from the neck.⁵,¹³,²⁷,⁴²,⁷⁰,¹¹⁸
The proposed mechanism is a fall on the hand with the elbow flexed,
which causes a momentary partial dislocation of the elbow and forces
the radial head posterior to the capitellum.

Some factors may be more important than the type of
treatment in determining the final result. A poor result is more likely
if the fracture is associated with other injuries, such as an elbow
dislocation, a fracture of the olecranon, or avulsion of the medial
epicondylar apophysis.²⁶,⁹² The magnitude of force to the elbow is a major factor in determining the quality of the result.⁵²,¹⁰³

Immobilization (Up to 30 Degrees of Angulation).
Immobilization is the treatment of choice for fractures in younger
children in which the angulation of the radial head is less than 20 to
30 degrees. A collar and cuff, a posterior splint, or a light long-arm
cast is sufficient to provide comfort and protection from further
injury. Aspiration of the intra-articular hematoma may decrease pain.

Manipulative Closed Reduction (30 Degrees to 60 Degrees
of Angulation). Although acceptable results can be obtained with
angulation of up to 45 degrees, closed reduction should be attempted
for fractures with more than 30 degrees of angulation. A closed
reduction is usually satisfactory for fractures with angulation up to
60 degrees. The chance of achieving a satisfactory closed reduction is
much less when the initial angulation exceeds 60 degrees.

Patterson’s Manipulative Technique. Some authors¹⁹,⁶⁰ advocate manipulative reduction with the elbow in extension, as described by Patterson.⁷⁵
General or regional anesthesia can provide adequate relaxation. The
orbicular ligament should be intact to stabilize the proximal radial
head fragment.⁶⁰ In Patterson’s⁷⁵ technique, an assistant grasps the arm proximal to the elbow joint with one hand (Fig. 11-19)
and places the other hand medially over the distal humerus to provide a
medial fulcrum for the varus stress applied across the elbow. The
surgeon applies distal traction with the forearm supinated to relax the
supinators and biceps. A varus force is then placed on the elbow to
overcome the ulnar deviation of the distal fragment so that it can be
aligned with the proximal fragment. This varus force also helps open up
the lateral side of the joint, which facilitates manipulation of the
head fragment.

Although forearm supination relaxes the supinator
muscle, supination may not be the best position for manipulation of the
head fragment. Jeffrey⁴² pointed out that the tilt of the radial

head can be anterior or posterior depending on the position of the
forearm at the time of injury. With this degree of rotation, the
prominent tilt of the proximal fragment can be felt laterally. The
direction of maximal tilt can be confirmed by radiograph. The best
position for reduction is the degree of rotation that places the radial
head most prominent laterally. If the x-ray beam is perpendicular to
the head in maximal tilt, it casts an oblong or rectangular shadow; if
not, the shadow is oval or almost circular.⁴²
With a varus force applied across the extended elbow, the maximal tilt
directed laterally, and the elbow in varus, the radial head can be
reduced with the pressure of a finger (see Fig. 11-19, right).

Neher and Torch⁶⁸
described a two-person technique for the reduction of severely
displaced radial neck fractures. This technique is performed with the
elbow in extension and the patient under general anesthesia. An
assistant uses both thumbs to place a laterally directed force on the
proximal radial shaft while the surgeon applies a varus stress to the
elbow. Simultaneously, the surgeon uses his other thumb to apply a
reduction force directly to the radial head (Fig. 11-20).

Kaufman et al.⁴⁵
proposed another technique in which the elbow is manipulated in the
flexed position. The surgeon presses his or her thumb against the
anterior surface of the radial head with the forearm in pronation.

Some authors recommend immobilization in pronation after
reduction because it is the forearm motion most often restricted after
fracture.¹²⁰ Some have recommended
supination because they believe it is easier for the patient to regain
active pronation than active supination during rehabilitation. Whether
pronation or supination is chosen, they recommend 90 degrees of flexion
for the elbow. Fluoroscopy can determine whether pronation or
supination results in the optimal reduction of the fracture.

In uncommon circumstances, the head fragment may be
completely displaced proximally, with the head perpendicular to the
shaft of the radius. In four reports since 1960, closed reduction,²⁷,¹²²,¹²⁴ resulted in rotation of the proximal fragment¹⁸⁰
degrees so that the articular surface of the head (concavity) was
facing the fracture surface of the radial neck. Open reduction is
needed to reduce the fragment, with a high risk of complications.

Although most fractures are stable after reduction,
redisplacement can occur, especially if the initial tilt was more than
60 degrees.²⁰,⁴³
Fractures with more than 90 degrees of angulation, especially those in
which the head fragment is lying free in the joint, are almost
impossible to reduce by closed methods.

Percutaneous Pin Reduction. The use of percutaneous pin
reduction with an image intensifier is a popular method of
satisfactorily reducing moderately to severely displaced fractures.³,⁶,¹⁹,⁷⁸,¹⁰² Various authors have used an awl, a Steinmann pin,⁸⁹ a periosteal elevator,²⁸ or a double-pointed “bident”³
that in theory controls rotation better. Some authors describe using
the pin to directly push the displaced radial head fragment back into
position,⁶¹ while others describe a pin leverage technique,⁷⁸,¹⁰² inserting the pin into the fracture site and then leveraging the radial head against the capitellum to reduce the fracture (Fig. 11-21). Pesudo et al.,⁷⁸
in their series of 22 displaced radial neck fractures, found that the
results after percutaneous pin reduction were superior to those after
open reduction.

Biyani et al.⁷
described driving the pin used to reduce the radial head across the
fracture site to stabilize it. The pin is removed and motion is allowed
after 3 weeks.

Intramedullary Pin Reduction. In 1980, Metaizeau et al.⁶²
proposed reducing severely tilted radial neck fractures with an
intramedullary wire passed from the distal metaphysis. A report 13
years later⁶¹ demonstrated the
effectiveness of this technique. A wire is inserted into the medullary
canal through an entrance hole in the distal metaphysis (Fig. 11-22).
Once the wire reaches the fracture site, the angulation at the tip
enables it to engage the proximal fracture site at the neck. Once
engaged, the wire is twisted to reduce the head and neck fragment. This
technique has produced results superior to open reduction with fewer
complications.³²,⁹⁸

Subsequently, multiple authors⁶⁷,⁸³,⁹⁶
have reported good to excellent results using the intramedullary pin
reduction technique for severely displaced radial neck fractures.
Schmittenbecher et al.⁹⁶ reported
good to excellent results in 18 (78%) of 23 fractures after reduction
and fixation with 2-mm elastic intramedullary nails. Other authors have
recommended using Kirschner-wires for the intramedullary technique. One
challenge with this technique is that oftentimes Kirschnerwires are not
long enough to allow for optimal use with the intramedullary reduction
method. However, the pointed tip of the Kirschner-wire is helpful in
engaging the displaced radial neck fragment during this reduction
maneuver. Nawabi et al.⁶⁷ reported
the use of a smooth 1.8-mm Ilizarov wire in two children. The added
length of the Ilizarov wire allowed sufficient wire to remain outside
the skin to simplify the reduction maneuver. When using a Kirschner
wire or Ilizarov wire, it is important to contour the distal 3 to 4 mm
with a relatively sharp bend to allow for easier capture of the
displaced radial head fragment. It remains controversial as to whether
or not the intramedullary implant needs to remain in place after the
fracture reduction.

Wallace Method for Reduction of Radial Neck Fracture.
Fluoroscopy in an AP projection is used to determine the forearm
rotation that exposes the maximum amount of deformity of the fracture,
and the level of the bicipital tuberosity of the proximal radius is
marked. A 1-cm dorsal skin incision is made at that level just lateral
to the subcutaneous border of the ulna. A periosteal elevator is gently
inserted between the ulna and the radius,

with
care not to disrupt the periosteum of the radius or the ulna. The
radial shaft is usually much more ulnarly displaced than expected, and
the radial nerve is lateral to the radius at this level. While
counterpressure is applied against the radial head, the distal fragment
of the radius is levered away from the ulna. An assistant can aid in
this maneuver by gently applying traction and rotating the forearm back
and forth to disimpact the fracture fragments. If necessary to correct
angulation, a percutaneous Kirschner-wire can be inserted into the
fracture site, parallel to the radial head, to lever the physis
perpendicular to the axis of the radius.

Once an adequate reduction has been obtained, an oblique
Kirschner-wire is inserted to provide fracture fixation. The wire is
removed 3 weeks after surgery (Figs. 11-23 and 11-24).

Open Reduction. With valgus injuries, a residual tilt of
45 degrees probably produces as good a result as trying to achieve a
perfect reduction surgically. An acceptable closed reduction can
produce a better result than an anatomically perfect open surgical
reduction (Table 11-3).

Early reviews reported poor results with significant loss of range of motion in patients treated operatively,⁹,¹¹,¹⁴,²¹ but more recently Steinberg et al.¹⁰³ combined their results of open reduction of severely displaced fractures with those of five other

series⁴²,⁴³,⁷⁸,¹¹⁰
and reported 49% good results after operative treatment compared to 25%
after nonoperative treatment. None of these authors used percutaneous
pin reduction. The results of moderately displaced fractures treated
operatively were equal to the results of those treated nonoperatively.

If the head of the radius is completely displaced,
results are usually better with surgical intervention. Some authors
have shown that a completely separated radial head remains viable if
surgically replaced as late as 48 hours after injury.³⁰,⁴⁶

Some fractures may be irreducible by closed means
because interposition of the capsule or annular ligament between the
head and neck blocks reduction.¹¹⁷ Strong et al.¹⁰⁵
described an unusual fracture pattern in which the radial head was
trapped by the orbicular ligament. They found that these fractures were
irreducible by closed methods and required open reduction.

Some authors⁶⁰,⁸⁹,⁹⁰
have recommended inserting a small wire through the capitellum across
the radial head and into the neck to fix radial head fractures, but
this technique has a high incidence of complications.²⁶,⁷⁰,⁹⁷,¹²⁰ Even in a long-arm cast, the elbow joint has slight motion, which can cause the pin to fatigue and break (Fig. 11-25).
The retrieval of the remaining portion of the pin from the proximal
radius is almost impossible without imposing considerable trauma. Even
if the pin does not break, the motion of the pin may erode the joint
surface and fragment the radial head.⁷⁰,¹²⁰

Other suggested methods of fixing the displaced radial
neck after open reduction include intramedullary bone pegs, direct pin
insertion through the head by way of an olecranon osteotomy,⁵⁵ or with a forked plate.⁵¹

The most common technique in current use involves placement of a pin obliquely across the fracture site into the radial head.¹⁹,²⁶,⁴³ The pin can be placed either proximal to distal (Fig. 11-26) or, preferably, distal to proximal. The protruding pin is easy to remove after the fracture heals.

Some believe that internal fixation is unnecessary after open reduction.⁸,⁷⁰,¹²⁰ Wedge and Robertson¹²⁰
found that patients without internal fixation had more good results
than those with internal fixation. Use of internal fixation does not
guarantee that the fragment will not slip. Newman⁷⁰ described two patients in whom the head slipped postoperatively despite Kirschnerwire fixation.

One complication of open reduction is injury to the posterior interosseous nerve. To avoid this complication, Jones and Esah⁴³ recommended identifying the nerve as it courses through the supinator muscle. Kaplan⁴⁴ and Strachan and Ellis¹⁰⁴
demonstrated that with the forearm in pronation, the posterior
interosseous nerve displaces ulnarward, out of the way of the surgical
dissection. They also recommended that the patient be prone during
exploration of the proximal radius to help keep the forearm pronated.

The orbicular ligament should be left intact if possible. If dividing it is necessary for reduction, it should be repaired.²⁶

For type B (Salter-Harris type IV) fractures, a small
marginal fragment can be safely removed and the remaining large portion
of the head reduced without internal fixation.¹²⁰

Pelto et al.⁷⁷
reported good to excellent results with the use of absorbable
polyglycolide pins in patients older than 13 years of age. Transient
local abacterial tissue reaction occurred but did not lead to any
long-term negative effects. There was no comment on the effect on the
physis. To fix a large displaced head fragment in a Salter-Harris type
III or IV fracture, a transepiphyseal screw is useful (Fig. 11-27).

Radial Head Excision. Resection of the radial head
fragment was popular in the 1920s and 1930s, but reported results have
been uniformly poor.²⁰,³⁹,⁴³ Cubitus valgus and radial deviation at the wrist are common sequelae. The procedure is contraindicated in a growing child.

Loss of motion is secondary to a combination of loss of
joint congruity and fibrous adhesions. Loss of pronation is more common
than loss of supination. Flexion and extension are rarely significantly
limited. Enlargement of the radial head, a common sequela, can
contribute to the subsequent loss of elbow motion.³⁰

Next to loss of range of motion of the elbow and
forearm, radial head overgrowth is probably the most common sequela
(20% to 40%).¹⁵,¹¹⁴
The increased vascularity following the injury may stimulate epiphyseal
growth, but the mechanisms of overgrowth following fractures are poorly
understood. Radial head overgrowth usually does not compromise
functional results,¹⁹,⁴³ but it may produce some crepitus or clicking with forearm rotation.¹⁵

O’Brien⁷¹ suggested
that notching of the radial head in several patients was secondary to
scar tissue forming around the neck from the orbicular ligament. It did
not result in any functional deficit. Notching may be a normal variant
of radial head anatomy.

Many series report premature physeal closure²⁶,³⁰,⁷⁰,⁷¹,¹⁰³,¹²⁰
after fractures of the radial head and neck. This complication did not
appear to affect the overall results significantly, except in one
patient described by Fowles and Kassab,²⁶ who had a severe cubitus valgus. Newman⁷⁰ found that shortening of the radius was never more than 5 mm compared with the opposite uninjured side.

Nonunion of the radial neck is rare; union may occur⁹⁷ after prolonged treatment (Fig. 11-33). Waters and Stewart¹¹⁹
reported nine patients with radial neck nonunions, all of whom were
treated with open reduction after failed attempts at closed reduction.
These authors recommended observation of patients with radial neck
nonunions who have limited symptoms and a functional range of motion.
They suggested open reduction for displaced nonunions, patients with
limited range of motion, and patients with restricting pain.

The incidence of osteonecrosis is probably higher than recognized. D’Souza et al.¹⁵
reported the frequency to be 10% to 20% in their patients, 70% of whom
had open reductions. In patients with open reduction, the overall rate
of osteonecrosis was 25%. Jones and Esah⁴³ and Newman⁷⁰
found that patients with osteonecrosis had poor functional results. It
has been our experience, however, that revascularization can occur
without any significant functional loss. Only in those in whom a
residual functional deficit occurs is osteonecrosis considered a
problem (Fig. 11-34).

In patients who have fractures of the radial neck, the
carrying angle often is 10 degrees more (increased cubitus valgus) than
on

the uninjured side.¹⁵,⁴³ The increase in carrying angle appears to produce no functional deficit and no significant deformity.

There are no reports of major vascular injuries with isolated fractures of the proximal radius.

Partial ulnar nerve injury³⁹
and posterior interosseous nerve injury may occur as a direct result of
the fracture, but most injuries to the posterior interosseous nerves
are caused by surgical exploration¹⁵ or percutaneous pin reduction.⁵ These posterior interosseous nerve injuries usually are transient.

Peters and Scott⁷⁹
described three patients with volar forearm compartment syndrome after
minimally displaced or angulated fractures of the radial head. All
required volar fasciotomy.

Proximal synostosis is the most serious complication that can occur after radial head fracture (Fig. 11-35). It occurs most often after open reduction of severely displaced fractures,³⁰,³⁹,⁷⁰,¹⁰²
but it can occur after closed reduction. Delayed treatment increases
the likelihood of this complication. All three patients described by
Gaston et al.³⁰ had treatment initiated more than 5 days after injury.

Myositis ossificans is relatively common but usually does not impair function. Vahvanen¹¹⁴
noted that some myositis ossificans occurred in 32% of his patients. In
most, it was limited to the supinator muscle. If ossification was more
extensive and was associated with a synostosis, the results were poor.

Veranis et al.¹¹⁵
reported a rare case of hematogenous osteomyelitis after a closed
fracture of the radial neck. The diagnosis was delayed despite the fact
that the child had fever and continuous pain after the fracture.

Failure to reduce a displaced and angulated proximal
radial fracture in a young child often results in an angulated radial
neck with subsequent incongruity of both the proximal radioulnar joint
and the radiocapitellar joint (Fig. 11-36). Partial physeal arrest also can create this angulation (see Fig. 11-5).

In our experience, this malunion, because of the
incongruity of the radiocapitellar joint, often results in erosion of
the articular surface of the capitellum, with subsequent degenerative
joint disease. In the English literature, there is little information
about using osteotomies of the radial neck to correct this deformity.

“Separation of the olecranon epiphysis is the rarest form of epiphyseal detachment.”⁸⁰
This quote from Poland’s 1898 textbook on epiphyseal fractures is still
true. Few fractures of the ulnar apophysis are described in the English
literature.³⁴,⁸⁰,⁹⁵,¹⁰¹ In addition to acute injuries in children, some have been described in young adults with open physes.⁴⁷,⁷⁶,¹⁰⁰,¹¹¹ In the French literature, Bracq¹⁰
described 10 patients in whom the fracture extended distal and parallel
to the apophyseal line and then crossed it at the articular surface.
Most reports of apophyseal olecranon fractures describe patients with
osteogenesis imperfecta, who seem predisposed to this injury.

The Ossification Process. At birth, the ossification of
the metaphysis of the proximal ulna extends only to the midportion of
the semilunar notch. At this age, the leading edge of the metaphysis is
usually perpendicular to the long axis of the olecranon (Fig. 11-37A,B).
As ossification progresses, the proximal border of the metaphysis
becomes more oblique. The anterior margin extends proximally and to
three fourths of the width of the semilunar notch by 6 years of age. At
this age, the physis extends distally to include the coronoid process
(see Fig. 11-37C). A secondary center of
ossification occurs in the coronoid process. Just before the
development of the secondary center of ossification in the olecranon,
the leading edge of the metaphysis develops a well-defined sclerotic
margin.⁹⁵ Ossification of the olecranon occurs in the area of the triceps insertion at approximately 9 years of age (see Fig. 11-37D).⁹⁵ Ossification of the coronoid process is completed about the time that the olecranon ossification center appears.⁸⁰
The term “apophysis” is usually applied to an epiphysis that is
subjected to traction by a muscle insertion. “Apophysis” and
“epiphysis” are used interchangeably in this chapter to describe the
olecranon secondary growth center because it contributes to length and
articular surface as well.

Bipartite Centers. The secondary ossification center of the olecranon may be bipartite (see Fig. 11-37E).⁸² The major center

within the tip of the olecranon is enveloped by the triceps insertion. This was referred to by Porteous⁸² as a traction center.
The second and smaller center, an articular center, lies under the
proximal fourth of the articular surface of the semilunar notch.

Closure Process. Fusion of the olecranon epiphysis with
the metaphysis, which progresses from anterior to posterior, occurs at
approximately 14 years of age. The sclerotic margin that defines the
edge of the metaphysis may be mistaken for a fracture (see Fig. 11-37F).⁹⁵ Rarely, the physeal line persists into adulthood,⁴⁷,⁷⁶,¹¹¹ usually in athletes who have used the extremity in repetitive throwing activities.¹⁶,⁸⁷,¹⁰⁰,¹¹³,¹²¹ The chronic tension forces applied across the apophysis theoretically prevent its normal closure.

Patella Cubiti. Occasionally, a separate ossification center called a patella cubiti develops in the triceps tendon at its insertion on the tip of the olecranon.¹⁰⁹
This ossicle is completely separate and can articulate with the
trochlea. It is usually unilateral, unlike other persistent secondary
ossification centers, which are more likely to be bilateral and
familial. Zeitlin¹²⁶ believed that the patella cubiti was a traumatic ossicle rather than a developmental variation.

Clinical: Swelling Plus Defect. The primary clinical
findings of an olecranon fracture are tenderness and swelling. If the
fragment is completely displaced, the child cannot extend the elbow. A
palpable defect may be present between the apophysis and the proximal
metaphysis. Poland⁸⁰ described the crepitus between the fragments as being muffled because cartilage covers the fracture surfaces.

Radiography: Proximal Metaphyseal Displacement. The
radiographic diagnosis may be difficult before ossification of the
olecranon apophysis. The only clue may be a displacement of the small
ossified metaphyseal fragment (Fig. 11-38), and
the diagnosis may be based only on the clinical sign of tenderness over
the epiphyseal fragment. If there is any doubt about the degree of
displacement, injection of radiopaque material into the joint may
delineate the true nature of the fracture.

The location of the triceps expansion insertion on the
metaphysis distal to the physis probably accounts for the rarity of
fracture along the physeal line. Only a few reports mention the
mechanism of these physeal injuries. In most of the fractures reported
by Poland,⁸⁰ three of which were confirmed by amputation

specimens, the force of the injury was applied directly to the elbow.
The force may be applied indirectly, producing an avulsion type of
fracture. In our experience, this fracture is usually caused by
avulsion forces across the apophysis with the elbow flexed, similar to
the more common flexion metaphyseal injuries. Children with
osteogenesis imperfecta (usually the tarda form) seem especially
predisposed to this injury.¹⁷,⁶³

Stress fractures of the olecranon apophysis can occur in
athletes (especially baseball players) who place considerable recurrent
tension forces on the olecranon.⁷⁴ Stress injuries also have been reported in elite gymnasts⁵⁴ and tennis players.⁸⁷ If the recurring activity persists, a symptomatic nonunion can develop.⁷⁶,⁸⁷,¹¹¹,¹¹³,¹²¹

Injuries to the apophysis of the olecranon can be classified as one of three types (Table 11-6). Type I is a simple apophysitis in which there is irregularity in the secondary ossification center (Fig. 11-39A).¹⁶,⁵⁴
The apophyseal line may widen. Type II is an incomplete stress fracture
that involves primarily the apophyseal line, with widening and
irregularity (see Fig. 11-39B). A small
adjacent cyst may form, but usually the architecture of the secondary
ossification center is normal. These injuries occur primarily in sports
requiring repetitive extension of the elbow, such as baseball pitching,⁷⁴ tennis,⁸⁷ or gymnastics.⁵⁴
Type III injuries involve complete avulsion of the apophysis. True
apophyseal avulsions (type IIIA) occur in younger children as a
fracture through the apophyseal plate (see Fig. 11-39A,B). In some of his amputation specimens, Poland⁸⁰
found that the proximal apophyseal fragment included the distal tongue,
which extended up to the coronoid process. Apophyseal-metaphyseal
combination fractures (type IIIB), in which metaphyseal fragments are
attached to the apophysis (see Fig. 11-39C,D), usually occur in older children. Grantham and Kiernan³⁴
likened it to a Salter-Harris type II physeal injury. Proximal
displacement of the fragment is the only clue seen on a radiograph.

There is no standard method of treatment, because few
such fractures have been described. For fractures with significant
displacement, treatment is usually open reduction with internal
fixation using a combination of axial pins and tension-band wiring (Fig. 11-40).³⁴,⁸⁰,¹⁰¹ Gortzak et al.³³
described a technique of open reduction using percutaneously placed
Kirschner-wires and absorbable sutures instead of wires for the tension
band. The percutaneously placed wires are subsequently removed 4 to 5
weeks postoperatively, eliminating the need for implant removal. There
has been concern that applying compressive forces across the apophysis
might cause growth arrest. In our experience, fusion of the apophysis
to the metaphysis is accelerated. Apophyseal fractures usually occur
when the physis is near natural closure. The growth proximally is
appositional rather than lengthwise across the apophyseal plate itself.
As a result, we have not found any functional shortening of the
olecranon because of the early fusion of the apophysis to the
metaphysis (see Fig. 11-40D). In practice, the
use of a compression screw across an ossified olecranon fracture causes
no loss of ulnar length. Children who sustain injuries before the
development of the secondary ossification center may develop a
deformity that is visible on radiographs (Fig. 11-41).
Although there may be shortening of the olecranon, it does not appear
to produce functional problems. There are no reports of the effects of
this injury in very young children or infants. Most stress injuries
respond to simple rest from the offending activity.

However,
a chronic stress fracture can result in a symptomatic nonunion. Use of
a compressive screw alone across the nonunion often is sufficient,⁵⁴ but supplemental bone grafting may be necessary to achieve union.⁴⁷,⁷⁶

Smith⁸¹ noted that
overgrowth of the epiphysis proximally may produce a bony spur. In some
patients, these proximal spurs became symptomatic and were removed.

The cause and treatment of nonunion are discussed in the previous section.

Apophyseal arrest appears to have no significant effect on elbow function (see Fig. 11-41).

Isolated metaphyseal fractures of the olecranon are relatively rare (Table 11-7).
They are often associated with other fractures about the elbow. In the
combined series of 4684 elbow fractures reviewed, 230 were olecranon
fractures, for an incidence of 4.9%. This agrees with the incidence of
4% to 6% in the major series reported.²⁵,⁵⁸,⁷³ Only 10% to 20% of the total fractures

reported in these series required an operation. Six reports totaling
302 patients with fractures of the olecranon in children are in the
English literature.²⁹,³⁴,⁵⁸,⁶⁹
Considering all age groups, 25% of olecranon fractures in these reports
occurred in the first decade and another 25% in the second decade.⁴⁹ During the first decade, the peak age for olecranon fracture was between age 5 and 10 years.³⁵,⁶⁹
Approximately 20% of patients had an associated fracture or dislocation
of the elbow, most involving the proximal radius. Only 10% to 20%
required an operation.

Because the olecranon is a metaphyseal area, the cortex
is relatively thin, allowing for the development of greenstick-type
fracture deformities. The periosteum is immature and thick, which may
prevent the degree of separation seen in adults. Likewise, the larger
amount of epiphyseal cartilage in children may serve as a cushion to
lessen the effects of a direct blow to the olecranon. In the production
of supracondylar fractures, ligamentous laxity in this age group tends
to force the elbow into hyperextension when the child falls on the
outstretched upper extremity. This puts a compressive force across the
olecranon and locks it into the fossa in the distal humerus, where it
is protected. An older person, whose elbow does not go into
hyperextension, is more likely to fall with the elbow semiflexed. This
unique biomechanical characteristic of the child’s olecranon
predisposes it to different fracture patterns than those in adults.

Flexion injuries cause soft tissue swelling over the
olecranon fracture. The abrasion or contusion associated with a direct
blow to the posterior aspect of the elbow provides a clue as to the
mechanism the injury. If there is wide separation, a defect can be
palpated between the fragments. In addition, there may be weakness or
even lack of active extension of the elbow, which is difficult to
evaluate in an anxious young child with a swollen elbow.

On radiograph, the fracture lines associated with
flexion injuries are usually perpendicular to the long axis of the
olecranon. This differentiates them from the residual physeal line,
which is oblique and directed proximal and anterior.⁹⁵
In extension injuries, the longitudinally directed greenstick fracture
lines may be difficult to appreciate, and radiographs should be
scrutinized to detect associated fractures of the proximal radius or
distal humerus.

Papavasiliou et al.⁷³
defined two major groups of olecranon fractures in which the fracture
line is either intra-articular or extra-articular. The degree of
displacement defines subclassifications in each group. We prefer to
classify these fractures based on the mechanism of injury (Table 11-8):
those associated with flexion injuries, those associated with extension
injuries, and shear injuries. Extension injuries are further divided
into varus and valgus patterns.

Three main mechanisms produce metaphyseal olecranon
fractures, depending on whether the elbow is flexed or extended at the
time of injury. First, in injuries occurring with the elbow flexed,
posterior tension forces play an important role. Second, in injuries in
which the fracture occurs with the elbow extended, the varus or valgus
bending stress across the olecranon is responsible for the typical
fracture pattern. Third, a less common mechanism involves a direct blow
to the elbow that produces an anterior bending or shear force across
the olecranon. In this type, the tension forces are concentrated on the
anterior portion of the olecranon.

Associated injuries occur in 48% to 77% of patients with olecranon fractures,¹²,³⁵,⁷³,¹⁰⁸ especially varus and valgus greenstick extension fractures, in which the radial head and neck most commonly fracture (see Fig. 11-45). Other associated injuries include fractures of the ipsilateral radial shaft,¹⁰⁶ Monteggia type I lesions with fractures of both the ulnar shaft and olecranon,⁷² and fractures of the lateral condyle (Fig. 11-49).¹⁰

The mechanism of injury can serve as a useful guide in choosing the proper treatment method.

An and Loder¹ reported inability to reduce the fracture in one of their patients because the proximal fragment was entrapped in the joint.

Nonunion is unusual and should not be confused with congenital pseudarthrosis of the ulna, which is rare (Fig. 11-55). In the latter condition, there is no antecedent trauma.

Delayed radiographic union usually is asymptomatic.⁵⁷ In Mathews’ series,⁵⁷
one fracture treated with suture fixation ultimately progressed to a
nonunion. Despite this, the patient had only a 10 degrees extension lag
and grade 4 triceps strength. An accessory ossicle, such as a patella
cubiti, is not a nonunion.

Mathews⁵⁷ described 1 patient with Volkmann ischemic contracture after an undisplaced linear fracture in the olecranon.

Zimmerman¹²⁷ reported ulnar nerve neurapraxia from the development of a pseudarthrosis of the olecranon where inadequate fixation was used.

Elongation of the tip of the olecranon may complicate healing of a fracture. Figure 11-56
illustrates a delayed union in which the apophysis became elongated to
the point that it limited extension. This proximal overgrowth of the
tip of the apophysis has occurred in olecranon fractures after routine
open reduction and internal fixation.⁷³

Apparently stable fractures treated with external
immobilization may lose reduction, which results in a significant loss
of elbow function (Fig. 11-57).

Anatomy. Up to age 6 years, the coronoid process
consists of epiphyseal and physeal cartilage at the distal end of a
tongue extending from the apophysis of the olecranon. The coronoid
process does not develop a secondary center of ossification, but
instead ossifies along with the advancing edge of the metaphysis (see Fig. 11-37).

Incidence. The incidence of fracture of the coronoid varies from less than 1% to 2% of elbow fractures.⁵⁸
Because most fractures of the coronoid process occur with dislocations
of the elbow, it seems logical that they would happen in older
children. However, in a review of 23 coronoid fractures in children,
Bracq¹⁰ found that the injuries
occurred in 2 peak age groups: one was between 8 and 9 years of age and
the other between 12 and 14 years.

Although most coronoid fractures are associated with
elbow dislocations, fractures of the olecranon, medial epicondyle, and
lateral condyle also can occur.⁷⁰ The fracture of the coronoid may be part of a greenstick olecranon fracture (i.e., the extension-type metaphyseal fracture; Fig. 11-58).
Isolated coronoid fractures are theoretically caused by avulsion by the
brachialis or secondary to an elbow dislocation that reduced
spontaneously, which is usually associated with hemarthrosis and a
small avulsion of the tip of the olecranon process (Fig. 11-59).

Diagnosis. The radiographic diagnosis of this fracture
is often difficult because on the lateral view the radial head is
superimposed over the coronoid process. Evaluation of a minimally
displaced fracture may require oblique views (Fig. 11-60).¹⁰³ The radiocapitellar view (see Fig. 11-6) shows the profile of the coronoid process.

In young children, in whom the coronoid process contains mostly cartilage, an unusual flap injury may occur.³⁰ In this rare injury, the elbow dislocates and the articular surface flips

back into the joint. The only clue to this fracture may be the presence
of a small flake of bone in the anterior part of the joint on the
lateral radiograph.

Classification. Regan and Morrey⁸⁵ classified coronoid fractures into three types based on the amount of the coronoid process involved (Table 11-9).
This classification is useful in predicting the outcome and in
determining the treatment. Type I fractures involve only the tip of the
process (see Fig. 11-59), type II fractures involve more than just the tip but less than 50% of the process (see Fig. 11-60), and type III fractures involve more than 50% of the process.

Treatment. The degree of displacement or the presence of
elbow instability guides the treatment. The associated injuries also
are a factor in treatment. Regan and Morrey⁸⁵,⁸⁶
treated types I and II fractures with early motion if there were no
contradicting associated injuries. For initial immobilization, if the
fracture is associated with an elbow dislocation, the elbow is placed
in approximately 100 degrees of flexion, with the forearm in full
supination.⁷⁰ Occasionally, in
partial avulsion fractures, the fracture reduces more easily with the
elbow in extension. In these rare cases, the brachialis muscle may be
an aid in reducing the fragment in extension.⁶⁹ Regan and Morrey⁸⁵
found that the elbow often was unstable in type III fractures, and they
secured these fractures with internal fixation. They had satisfactory
results with type I and II fractures, but in only 20% of type III
fractures were the results satisfactory.