Dislocations Of The Elbow

The first stage in a posterior or posterolateral
dislocation is a disruption of the ulnar collateral ligaments or
failure of the medial epicondyle apophysis. This produces valgus
instability.

The
proximal radius and ulna displace laterally with the intact biceps
tendon acting as the center of rotation for the displaced forearm (Fig. 16-4).
Application of both abduction and extension forces with anterior soft
tissue disruption results in a posterior or posterolateral elbow
dislocation.¹⁰⁰,¹²⁸

Posterior elbow dislocation must be differentiated from
extension-type supracondylar fracture of the distal humerus. With both
injuries, the elbow is held semiflexed, and swelling may be
considerable. Swelling initially is usually less with a dislocation
than with a type III supracondylar humeral fracture. Crepitus is
usually absent in children with a dislocation and the forearm appears
shortened. The prominence produced by the distal humeral articular
surface is more distal and is palpable as a blunt articular surface.
The tip of the olecranon is displaced posteriorly and proximally so
that its triangular relationship with the epicondyles is lost. The skin
may have a dimpled appearance over the olecranon fossa. If the
dislocation is posterolateral, the radial head also may be prominent
and easily palpable in the subcutaneous tissues.

Concomitant fractures occur in over one half of posterior elbow dislocations.⁷²,⁹⁷,¹¹⁴,¹¹⁶
Fractures involving the medial epicondyle, radial head and neck, and
coronoid process are most common. Fractures involving the lateral
epicondyle, lateral condyle, olecranon, capitellum, and trochlea occur
less frequently.²¹

Posterior dislocations normally produce moderate soft
tissue injury and can be associated with neurovascular injuries and
concomitant fractures (Fig. 16-5). The anterior
capsule fails in tension, opening the joint cavity. Radial head
displacement strips the capsule from the posterolateral aspect of the
lateral condyle with the adjacent periosteum. Because of the large
amount of cartilage on the posterolateral aspect of the lateral
condyle, the posterior capsule may not reattach firmly with healing.
This lack of a strong reattachment is believed to be a factor in
recurrent elbow dislocations.¹⁰¹ In a series of 62 adults and adolescents with elbow dislocations requiring surgical treatment, McKee et al.⁸⁷ reported that disruption of the lateral collateral ligament complex occurred in all 62 elbows.

Medially, the ulnar collateral ligament complex is
disrupted either by an avulsion of the medial epicondyle or a direct
tear of the ligament.¹²³,¹²⁸ Cromack²³
found that with medial epicondylar fractures, the origins of the ulnar
collateral ligaments and the medial forearm flexor muscles remain as a
unit, along with most of the pronator teres, which is stripped from its
humeral origin proximal to the epicondyle. These structures are then
displaced posterior to the medial aspect of the distal humerus. The
ulnar collateral ligaments and the muscular origins of the common
flexor muscles tear if the epicondyle remains

attached
to the humerus. With posterolateral displacement of the forearm, the
medial aspect of the distal humerus most often passes into the
intermuscular space between the pronator teres posteriorly and the
brachialis anteriorly. The brachialis, because it has little distal
tendon, is easily ruptured. The rent in the anterior capsule usually is
in this same area.

The structure most commonly torn on the lateral aspect of the elbow is the annular ligament.¹²⁸
On occasion, the lateral collateral ligament either avulses a small
osteochondral fragment from the lateral epicondyle or tears completely
within its substance.

When the elbow is dislocated, the medial aspect of the
distal humerus lies subcutaneously between the pronator teres
posteriorly and the brachialis anteriorly. The median nerve and
brachial artery lie directly over the distal humerus in the
subcutaneous tissues. In a cadaver and clinical study by Louis et al.,⁷⁴
there was a consistent pattern of disruption of the anastomosis between
the inferior ulnar collateral artery and the anterior ulnar recurrent
artery. If the main brachial arterial trunk also is compromised, the
loss of this collateral system can result in the loss of circulation to
the forearm and hand.

The ulnar nerve is also at risk in posterior elbow dislocation because of its position posterior to the medial epicondyle.

Anteroposterior and lateral x-rays usually are
diagnostic of a posterior elbow dislocation. There is a greater
superimposition of the distal humerus on the proximal radius and ulna
in the anteroposterior view. The radial head may be proximally and
laterally displaced, or it may be directly behind the middistal
humerus, depending on whether the dislocation is posterolateral,
posterior, or posteromedial (Fig. 16-6). The
normal valgus angulation between the forearm and the arm usually is
increased. On the lateral view, the coronoid process lies posterior to
the condyles. The x-rays must be examined closely for associated
fractures. Subtle osteochondral fracture fragments can become entrapped
in the joint. If anatomic, congruent reduction is not feasible, and
further evaluation with computerized tomography or magnetic resonance
imaging is utilized to further define complex injury patterns.

If untreated, elbow dislocation predictably results in
dramatic loss of elbow function characterized by loss of motion and
eventually pain (Fig. 16-7). In comparison,
reduction of the dislocated elbow usually achieves marked improvement
of acute pain as well as restoration of long-term function.

Closed reduction of posterior elbow dislocations is successful in most cases. In the combined series of 317 dislocations,⁷²,⁹⁷,¹¹⁴,¹¹⁶ only two cases⁷² could not be reduced by closed methods. In the Carlioz and Abols²¹ series, two dislocations

reduced spontaneously and closed reduction was successful in 50 cases, but failed in 6 cases (10%). Josefsson et al.⁶³ reported that all 25 dislocations without associated fractures were successfully reduced.

Progressive elbow swelling secondary to the soft tissue
injury associated with an elbow dislocation makes it imperative that
the joint be promptly reduced. Royle¹¹⁶ found that dislocations reduced soon after the injury had better outcomes than those in which reduction was delayed.

All methods of closed reduction must overcome the
deforming muscle forces so that the coronoid process and the radial
head can slip past the distal end of the humerus. Adequate sedation or
anesthesia is necessary to permit muscle relaxation. Before the primary
reduction forces are applied, the forearm is hypersupinated to dislodge
the coronoid process and radial head from their position behind the
distal humerus and to reduce tension on the biceps tendon.¹⁰¹ The reducing forces are applied in two major directions (Fig. 16-8).
The first reducing force must be along the long axis of the humerus to
overcome the contractions of the biceps and brachialis anteriorly and
the triceps posteriorly. Once these forces are neutralized, the
proximal ulna and radius must be passed from posterior to anterior.

This
requires a second force along the long axis of the forearm. There
appears to be two main philosophies as to the best method of applying
force to counteract the muscles of the arm: the “pullers”¹⁰,²⁴,¹⁰³ (Figs. 16-9, 16-10 and 16-11) and the “pushers”⁷¹,⁹¹,⁹³ (Fig. 16-12). There also are combined unassisted pusher-puller techniques.⁴⁶,⁷⁰

Previous authors⁷²,¹⁴¹ have strongly advised against initial hyperextension before reduction forces are applied to the elbow. Loomis⁷³
demonstrated that when the coronoid process is locked against the
posterior aspect of the humerus and the elbow is extended, the force
applied to the anterior muscles is multiplied by as much as five times
because of the increased

leverage. This places a marked strain on the injured anterior capsule and the brachialis muscle (Fig. 16-13).
By contrast, when the distal force is applied to the proximal forearm
with the elbow flexed, the force exerted against the muscles across the
elbow is equal to the distracting force. For patients with
posterolateral dislocations, the lateral displacement of the proximal
radius and ulna must first be corrected to prevent the median nerve
from being entrapped or injured during reduction.¹¹,¹⁶ Hyperextension reduction puts the median nerve more at risk for entrapment.

Postreduction Care. After reduction, the surgeon should
determine and document the stability of the elbow by examination while
the patient is under sedation. A concentric reduction must be
documented in all cases. Some type of immobilization, usually a
posterior splint, is advocated by most investigators. A frequently
recommended period of immobilization is 3 weeks,⁷²,⁷³,¹⁰³,¹²⁵ although some have advocated early motion.¹¹⁵,¹¹⁶,¹⁴⁷
In a recent study of 42 adult patients comparing 2 weeks of cast
immobilization with the use of a simple arm sling and early motion,
Maripuri et al.⁸³ demonstrated
improved early and final functional outcomes in the early mobilization
group compared to the group placed in a cast following reduction.
O’Driscoll et al.¹⁰⁰ suggested that
if the elbow was stable in response to valgus stress with the forearm
pronated then the anterior portion of the medial collateral ligament
was intact and the patient could begin early motion. Ninety degrees of
elbow flexion appears to be the standard position of immobilization.

Indications for primary open reduction include an
inability to obtain a concentric closed reduction, an open dislocation,
and a displaced osteochondral fracture.

Primary ligament repair is not routinely indicated.
Adults with posterior elbow dislocations without concomitant fracture
have no better function or stability following a primary ligamentous
repair than those treated nonoperatively.⁶¹,⁶² Excellent results have been reported by Josefsson et al.⁶³ in 28 children and adolescents with simple posterior dislocations treated nonoperatively.

Open Posterior Dislocations. Open dislocations have a high incidence of associated arterial injury.⁵⁰,⁶⁶,⁷²,⁷⁴
Operative intervention is necessary in open posterior dislocations to
irrigate and débride the open wound and elbow and to evaluate the
brachial artery. If there is vascular disruption, most advocate
vascular repair or reconstruction with a vein graft even in the
presence of adequate capillary refill. This lessens the risk of late
cold intolerance, dysesthesias, or dysvascularity.

Associated Fractures. Children with an elbow dislocation
can have an associated fracture of the coronoid, lateral condyle,
olecranon (Fig. 16-14), or medial epicondyle (Fig. 16-15).
Recently, fracture of the anteromedial facet of the coronoid has been
recognized as an important injury associated with elbow dislocations in
adolescents and adults.³¹,³² The presence of a concomitant displaced fracture is a common indication for surgical intervention.²¹,³⁸,¹⁴² Surgery for associated fractures produced better results than nonoperative treatment in the series of Carlioz and Abols,²¹ and similar results were reported by Wheeler and Linscheid.¹⁴²
Repair of an associated medial epicondylar fracture may also improve
elbow stability in throwing athletes when the injury is in the dominant
arm.¹²³,¹⁴⁷
Entrapment of a displaced medial epicondylae fracture within the joint
after reduction is an absolute indication for surgical treatment (see Fig. 16-15).
Ultimately, the of surgical treatment for fractures associated with an
elbow dislocation is based on the circumstances surrounding each
individual patient. Factors favoring operative treatment include older
patient age, instability of the elbow during examination under sedation
at the time of reduction, the presence of a displaced intra-articular
fracture, injury to multiple elbow stabilizers, injury to the patient’s
dominant arm, and anticipated significant sports or activity demands on
the elbow.

Postoperative Care. Immobilization after surgery depends
on the procedure performed. After open reduction, management is similar
to that after satisfactory closed reduction. The length of
immobilization for fractures is up to 3 to 4 weeks. Protected arc of
motion with a hinged brace or intermittent splinting is utilized
frequently to lessen the risk of posttraumatic contracture.

Closed reduction of pediatric elbow dislocations should
always be done with adequate analgesia, sedation, or anesthesia. In
addition to making the experience much less frightening and traumatic
for the child, adequate analgesia, sedation, or anesthesia will achieve
sufficient muscle relaxation for the reduction to be obtained more
effectively with less force, thereby reducing the risk of creating an
iatrogenic fracture (such as fracture of the radial neck) during
reduction.

Ulnar Nerve Lesions. In a combined series of 317 patients,⁷²,⁹⁷,¹¹⁴,¹¹⁶
the most commonly injured nerve was the ulnar nerve. Of the 32 patients
(10%) who had nerve symptoms after reduction, 21 had isolated ulnar
nerve injuries, 7 had isolated median nerve injuries, and in 4 patients
both the median and ulnar nerves were involved. Linscheid and Wheeler⁷²
recommended ulnar nerve transposition if ulnar nerve symptoms were
present in a patient undergoing open reduction and internal fixation of
a displaced medial epicondylar fracture. Except for the one patient
described by Linscheid and Wheeler,⁷² the reported ulnar nerve injuries were transient and resolved completely.

Radial Nerve Lesions. Radial nerve injury with posterior elbow dislocation is very rare. Watson-Jones¹⁴¹
reported two radial nerve injuries associated with elbow dislocation;
in both the symptoms rapidly resolved after reduction. Rasool¹¹¹ reported a third case.

Median Nerve Lesions. The most serious neurologic injury
involves the median nerve, which can be damaged directly by the
dislocation or can be entrapped within the joint. Median nerve injuries
occur most commonly in children 5 to 12 years of age. There were seven
median and four median-ulnar nerve injuries (3%) in the combined series.⁷²,⁹⁷,¹¹⁴,¹¹⁶

Types of Median Nerve Entrapment. Fourrier et al.,³⁶ in 1977, delineated three types of medial nerve entrapment (Fig. 16-16).

Type 1. The child has an
avulsion of the medial epicondyle or has a rupture of the medial
muscles at their origin and the ulnar collateral ligaments (see Fig. 16-16A).
This allows the median nerve, with or without the brachial artery, to
displace posteriorly. The nerve is especially prone to being entrapped
between the trochlea and the olecranon during the process of reduction
if the lateral displacement of the proximal radius and ulna is not
corrected before reduction. Hallett⁴⁵
demonstrated in cadavers that pronation of the forearm while the elbow
is hyperextended forces the median nerve posteriorly during the process
of reduction making it vulnerable to entrapment. This type of
entrapment also has been reported by other authors.⁸,¹¹,¹⁶,³⁶,⁴²,⁸⁴,¹⁰⁷,¹¹⁰,¹³²
Delay in diagnosis is common. In some patients with an associated
medial epicondylae fracture, the nerve can be so severely damaged after
being entrapped that neuroma resection and either nerve transposition
and direct repair or grafting is necessary.¹¹,⁴²,⁸⁴ Good recovery of nerve function has been reported.

If the nerve has been entrapped for a considerable period, the Matev sign may be present on the x-rays.⁸⁴
This represents a depression on the posterior surface of the medial
epicondylar ridge where the nerve has been pressed against the bone.⁸,²⁵,⁴²,⁴⁵,¹⁰⁷,¹¹⁰,¹³² This groove is seen on x-ray as two sclerotic lines parallel to the nerve (Fig. 16-17). This sign disappears when the nerve has been decompressed.

Type 2. The nerve is entrapped between the fracture surfaces of the medial epicondyle and the distal humerus (see Fig. 16-16B). The fracture heals and the nerve is surrounded by bone, forming a neuroforamen.¹⁰⁷,¹¹³,¹³²
This may or may not be visible on x-ray. The medial epicondyle is
osteomized to free the nerve. Again, decompression alone may be
adequate treatment, although neuroma resection and repair or
reconstruction with nerve grafts may be necessary.

Type 3. The nerve is kinked and entrapped between the distal humerus and the olecranon (see Fig. 16-16C). Only three injuries of this type have been reported.⁸,¹⁰⁶,¹⁰⁹ Decompression, neuroma resection, and repair resulted in return of good function over 6 to 24 months.

Al Qattan et al.³
described a fourth type of median nerve entrapment in a 14-year-old boy
who had a posterior elbow dislocation with a medial epicondylar
fracture. The median

nerve
was found entrapped in a healed medial epicondylar fracture (type 2) in
an anterior to posterior direction 18 months after injury. The nerve
then passed through the elbow joint in a posterior to anterior
direction (type 1). The nerve was so severely damaged that it had to be
resected and repaired with sural nerve grafts. A second type 4 median
nerve entrapment also requiring nerve segment resection and grafting
was reported by Ozkoc et al.¹⁰²

The combination of an associated fracture of the medial
epicondyle and significant median nerve dysfunction was cited by Rao
and Crawford¹¹⁰ as an absolute
indication for surgical exploration of the nerve because of the
frequency of median nerve entrapment with fractures of the medial
epicondyle (types 1 and 2). Magnetic resonance imaging (MRI) may be
helpful in defining the course of the median nerve if entrapment is
suspected.² Electromyography and
nerve conduction studies have been utilized to assist in operative
decision making. Painful dysesthesias with arc of motion is usually
indicative of entrapment. Once the entrapped nerve is removed from the
joint, neurologic function typically improves. Resection and repair or
nerve grafting are may be necessary.

Arterial injuries are uncommon with posterior elbow
dislocations in children and adolescents with only eight vascular
injuries (3%) reported in the combined series of 317 patients.⁷²,⁹⁷,¹¹⁴,¹¹⁶ However, Carlioz and Abols²¹
reported 4 patients with diminished radial pulses that resolved after
reduction. Arterial injuries have been associated with open
dislocations in which collateral circulation is disrupted.⁵⁰,⁶⁶,⁷⁴,¹¹⁷ In these situations, usually the brachial artery is ruptured,⁴⁴,⁵⁰,⁵⁴,⁶⁶,⁷⁴,⁸¹ but it also can be thrombosed¹⁴⁴ as well as entrapped in the elbow joint.⁵¹,¹⁰⁴,¹⁴⁴ Pearce¹⁰⁴
reported an entrapped radial artery in which there was a high
bifurcation of the brachial artery. When there is a complete rupture,
there usually is evidence of ischemia distally. However, the presence
of good capillary circulation to the hand or a Doppler pulse at the
wrist does not always mean the artery is intact.⁴⁴,⁵⁴
Arteriograms usually are not necessary because the arterial injury is
at the site of the dislocation. If imaging is indicated to evaluate
possible arterial injury, its minimal risk and invasiveness make
vascular ultrasound an attractive initial imaging choice.

Treatment usually consists of relocation of the elbow
dislocation which returns the displaced brachial vessels to their
normal position⁵¹,¹⁴⁴
and operative repair of those that are ruptured or severely damaged.
Ligation of the ends has been done in the past with adults, especially
if there was good capillary circulation distally,⁵⁰,⁶⁶
but this may predispose to late ischemic changes such as claudication,
cold sensitivity, or even late amputation. Most investigators recommend
direct arterial repair or a vein graft.⁴⁴,⁵⁴,⁷⁴,⁸¹,¹¹⁷ Louis et al.⁷⁴
recommended arterial repair because their cadaver studies demonstrated
that a posterior elbow dislocation usually disrupted the collateral
circulation necessary to maintain distal blood flow.

Almost all patients with elbow dislocations lose some range of elbow motion.²¹,³⁸,⁶¹,⁶²,⁶³ This loss is less in children than in adults⁶³
and usually is no more than 10 degrees of extension. This rarely is of
functional or cosmetic significance. However, this potential for loss
of motion must be explained to the parents before reduction and may be
an indication for a supervised rehabilitation program. If there is
displaced medial epicondylar nonunion, the loss of major range of
motion can be severe and limiting. Similarly, an incongruent elbow
joint will have marked limitations of motion.

True myositis ossificans should be differentiated from
heterotopic calcification, which is a dystrophic process. Myositis
ossificans involves ossification within the muscle sheath that can lead
to a significant loss of range of motion of the elbow. Disruption of
the brachialis muscle is believed to be a contributory factor.⁷³ Fortunately, myositis ossificans is rare in children.⁶³,¹³⁶ Although heterotopic calcification in the ligaments and capsule of the elbow is common,⁶³,¹¹⁴ it rarely results in loss of elbow function (Fig. 16-18).

In Neviaser and Wickstrom’s⁹⁷ series of 115 patients, 10 had x-ray evidence of myositis ossificans; all, however, were asymptomatic. Roberts¹¹⁴
differentiated true myositis ossificans from heterotopic calcification
in his series of 60 elbow dislocations, and noted that only 3 patients
had true myositis ossificans. Linscheid and Wheeler⁷²
reported that the incidence of some type of heterotopic calcification
was 28%, which was most common around the condyles. Only in five
patients was it anterior to the capsule (which probably represented
true myositis ossificans in the brachialis muscle). Four of these
patients had some decrease in elbow function. Josefsson et al.⁶³
reported that 61% of 28 children with posterior dislocations had
periarticular calcification, but this did not appear to be functionally
significant.

In dislocations with an associated fracture of the
radial neck, the incidence of a secondary proximal radioulnar
synostosis is increased (Fig. 16-19). This can occur regardless of whether the radial neck fracture is treated operatively or nonoperatively.¹⁶,²¹,¹⁰⁰ Carlioz and Abols²¹ reported a synostosis in 1 of 3 patients with posterior elbow dislocations associated with radial neck fractures.

Occasionally, a severe elbow dislocation results in
significant tearing of the anterior capsule. As a result, after
reduction, when all the stiffness created by the dislocation has
subsided, the patient may have some hyperextension (cubitus recurvatum)
of the elbow. This usually is minimally symptomatic but if asymmetric,
may be cosmetically disturbing to the parents and adolescent.

The pathology of recurrent dislocation involves any or
all of collateral ligament instability, capsular laxity, and bone and
articular cartilage defects.

Ligamentous and Capsular Laxity. Osborne and Cotterill¹⁰¹
suggested that articular changes are secondary and that the primary
defect is a failure of the posterolateral ligamentous and capsular
structures to become reattached after reduction (Fig. 16-20). Osborne and Cotterill¹⁰¹
proposed that the extensive articular cartilage covering the surface of
the distal humerus leaves little surface area for soft tissue
reattachment and the presence of synovial fluid further inhibits soft
tissue healing. With recurrent dislocations, the radial head impinges
against the posterolateral margin of the capitellum, creating an
osteochondral defect (Fig. 16-21). In addition
to the defect in the capitellar articular surface, a similar defect
develops in the anterior articular margin of the radial head. When
these two defects oppose each other, recurrence of the dislocation is
more likely. Subsequent studies have confirmed these findings in almost
all recurrent dislocations, especially in children.³³,⁴⁹,⁹⁹,¹³³,¹³⁸,¹⁴⁶

O’Driscoll et al.⁹⁹
described posterolateral instability in 5 patients, including 2
children, in whom laxity of the ulnar part of the radial collateral
ligament allowed a transitory rotary subluxation of the ulnohumeral
joint and a secondary dislocation of the radiohumeral joint. Patients
with posterolateral instability often describe a history of recurrent
temporary dislocation of the elbow but, when examined, exhibit no
unusual clinical findings. The instability is diagnosed with a
posterolateral rotary instability test. In some patients,
posterolateral rotary instability can be detected only with the patient
completely relaxed under general

anesthesia.
This test is done by holding the patient’s arm over the head while
applying proximal axial compression plus a valgus and supination force
to the forearm with the elbow flexed to 20 to 30 degrees (Fig. 16-22). O’Driscoll et al.⁹⁹
reported that surgical repair of the lax ulnar portion of the radial
collateral ligament eliminated the posterolateral rotary instability.
In children and adolescents, the same instability can occur from
cartilage nonunion of the origin of the radial collateral ligament.

Bone Defects. In addition to the osteochondral defects
in the capitellum and radial head, bone defects may include a shallow
semilunar notch resulting from a coronoid fossa process fracture or
multiple recurrent dislocations.

Nonoperative. There is only one report of successful nonsurgical management of recurrent elbow dislocations. Herring⁵³
used an orthosis that blocked the last 15 degrees of extension. After
his patient wore this orthosis constantly for 2 years and with vigorous
activities for another 6 months, there were no further dislocations,
but the follow-up period was only 1 year. Beaty and Donati⁹ emphasized that physical therapy and the use of an orthosis should be tried before surgery is considered.

Surgical Procedures. The treatment of recurrent
posterior elbow dislocations is predominately surgical. Various
surgical procedures have been described to correct bone and soft tissue
abnormalities (Fig. 16-23).

Bone Procedures. These are directed toward correcting dysplasia of the semilunar notch of the olecranon. Milch⁹² inserted a boomerang-shaped bone block. Others⁴¹,⁸⁸,¹⁴⁰ found that a simple bone block was all that was necessary (Fig. 16-23A). Mantle⁸² increased the slope of the semilunar notch in two patients with an opening wedge osteotomy of the coronoid process (Fig. 16-23B).

Soft Tissue Procedures. Reichenheim¹¹² and King⁶⁷ transferred the biceps tendon just distal to the coronoid process to

reinforce it (Fig. 16-23C). Kapel⁶⁵
developed a cruciate ligament reconstruction in which distally based
strips of the biceps and triceps tendon were passed through the distal
humerus (Fig. 16-23D). Beaty and Donati⁹
modified this technique by transferring a central slip of the triceps
through the humerus posterior to anterior and attaching it to the
proximal ulna.

The most widely accepted technique is that described by Osborne and Cotterill,¹⁰¹
in which the lateral capsule is reattached to the posterolateral aspect
of the capitellum with sutures passing through holes drilled in the
bone (Fig. 16-23E). The joint should be inspected at surgery because osteocartilaginous loose bodies may be present.⁴⁹,⁸⁰,¹³³ Since Osborne and Cotterill’s¹⁰¹ initial report of eight patients, successful use of this technique has been reported in numerous others.³³,⁴⁹,⁸⁰,⁹⁹,¹³³,¹³⁸,¹⁴⁶ Zeier¹⁴⁸ and O’Driscoll et al.⁹⁹ reinforced the lateral repair with strips of fascia lata, triceps fascia, or palmaris longus tendon.

Postoperatively, especially after the repair described by Osborne and Cotterill,¹⁰¹
the arm is immobilized in a long arm cast with the elbow flexed 90
degrees for 4 to 6 weeks. Protected active range of motion exercises
are performed for an additional 4 to 6 weeks. Strenuous activities are
avoided for 12 weeks postoperative.

Major complications after correction of recurrent
dislocations include loose osteocartilaginous fragments and destruction
of the articular surface of the joint (Fig. 16-24), elbow stiffness, or recurrent instability.

Children with untreated dislocations typically have pain and limited mid-range of motion (see Fig. 16-7).
Pathologically, there is usually subperiosteal new bone formation that
produces a radiohumeral horn, myositis ossificans of the brachialis
muscle, capsular contractures, shortening of the triceps muscle,
contractures of the medial and lateral collateral ligaments, and
compression of the ulnar nerve.³⁶,³⁷ These factors have to be considered when planning treatment.

Treatment Options. Closed reduction of dislocations recognized within 3 weeks of injury may be possible.⁴,³⁷ If this fails or if the dislocation is of longer duration, open reduction is necessary.

Surgical Procedures. Open reduction through a posterior approach, as described by Speed,¹³¹ involves lengthening of the triceps muscle and release or transposition of the ulnar nerve.³⁷ Satisfactory results usually can be obtained if a stable concentric

reduction is achieved within 3 months of the initial dislocation.⁴ Results after surgical reconstruction decline thereafter but still may produce some improvement in function.³⁰,³⁷,⁷⁸,⁹⁰,⁹⁴
Fixation of the elbow joint to maintain reduction with one or two large
smooth pins for 2 to 4 weeks followed by vigorous but protected
physical therapy has been recommended.³⁷,⁹⁴

Mahaisavariya et al.⁷⁹
reported improved extension and better functional results 1 to 3 months
after injury in 34 patients with chronic elbow dislocation
reconstruction in whom the triceps tendon was not lengthened compared
with 38 patients who had the triceps lengthened at surgery.

Anterior elbow dislocations usually are caused by a direct blow to the posterior aspect of the flexed elbow.⁵⁷ Hyperextension of the elbow also has been implicated in one study.¹⁴³ Twisting of the forearm on the elbow commonly occurs.

The elbow is held in extension upon presentation. There
is a fullness in the antecubital fossa. Swelling usually is marked
because of the soft tissue disruption associated with this type of
dislocation. There is severe pain with attempted motion. A careful
neurovascular examination is mandatory.

Routine anteroposterior and lateral x-rays are
diagnostic. In most cases, the proximal radius and ulna dislocate in an
anteromedial direction (Fig. 16-25). Associated
fractures are common. In children, the triceps insertion may be avulsed
from the olecranon with a small piece of cortical bone.¹⁴⁵ This fragment usually reduces to the olecranon after reduction. Wilkerson¹⁴³ reported an anterior dislocation associated with a displaced olecranon fracture in a 7-year-old boy. Inoue and Horii⁵⁷
reported an 11-year-old girl with an anterior elbow dislocation with
displaced fractures of the trochlea, capitellum, and lateral
epicondyle. These were repaired with open reduction and internal
fixation using Herbert bone screws.

Reduction usually is accomplished by flexing the elbow and pushing the forearm proximally and downward at the same

time.¹⁴⁵
As with posterior dislocations, a force must first be applied
longitudinally along the axis of the humerus with the elbow semiflexed
to overcome the forces of the biceps and triceps. The longitudinal
force along the axis of the forearm is directed toward the elbow (Fig. 16-26).
To make reduction easier, the distal humerus can be forced in an
anterior direction by pushing on the posterior aspect of the distal arm.

Surgery usually is not required unless the dislocation
is open, there is a brachial artery injury, or there is an associated
fracture that does not realign satisfactorily after closed reduction.
Open reduction and internal fixation of the fracture may then be
necessary.⁵⁷,¹⁴³

Because most anterior dislocations occur in flexion, the
elbow should be immobilized in some extension for 1 to 3 weeks,
followed by protected active range-of-motion exercises. Early motion
after open reduction and internal fixation of an associated olecranon
fracture usually can be allowed.⁵⁷,¹⁴³

Divergent dislocations are typically easily reduced
using closed reduction under general anesthesia. Reduction is achieved
by applying longitudinal traction with the elbow semiextended and at
the same time compressing the proximal radius and ulna together.

This is rarely indicated. There have been only three divergent dislocations reported that required open reduction.³⁵,⁸⁶,⁹⁶ Closed reduction failed in one child,⁸⁶ and another had a displaced fracture of the proximal ulna.³⁵
In the third child, after attempted closed reduction was unsuccessful,
surgical exploration found the avulsed anterior band of the medial
collateral ligament complex of the elbow was found to be interposed
between the medial condyle of the humerus and the olecranon.⁹⁶ After removing and repairing the interposed ligament, stable reduction was achieved.

After successful closed reduction, the elbow is
immobilized in 90 degrees of flexion and the forearm in neutral for
approximately 1 to 3 weeks. Active range-of-motion exercises are then
begun. Most patients typically regain full elbow motion, including
forearm pronation and supination.

Translocations are believed to be caused by a fall onto
the pronated hand with the elbow in full or nearly full extension,
producing an axial force on the proximal radius. The anterior radial
head dislocation occurs first, followed by the posterior dislocation of
the olecranon. The radial head, depending on the degree of pronation,
can be lodged in the coronoid fossa or dislocated posteriorly. As a
consequence, fractures of the radial head, radial neck, or coronoid
process may occur.¹⁹,²⁰,³⁴,⁷⁶ Harvey and Tchelebi ⁴⁷
reported a case in which the cause of radioulnar translocation may have
been iatrogenic: the result of inappropriate technique used to reduce a
posterior elbow dislocation.

Swelling and pain may obscure the initial examination,
and minimal deformity may be apparent. Once pain has been adequately
managed with analgesics, the most consistent finding on clinical
examination is limited elbow range of motion, especially in supination.

Radial neck fracture is the most common fracture associated with proximal radioulnar translocation.²⁰,³⁴,⁵⁸,⁷⁶ Eklöf et al.³⁴
also reported one patient who sustained a fracture of the tip of the
coronoid. Proposed soft tissue injuries include radial collateral
ligament, medial collateral ligament, annular ligament, and
interosseous ligament injury.³⁴,⁵⁸ Isbister⁵⁸ described transient

ulnar nerve paresthesia that resolved after reduction of the
translocation. Osteonecrosis of the radial head was noted in one
patient after open reduction of a proximal radioulnar translocation.⁴⁷

Successful closed reduction of proximal radioulnar translocation has been reported.⁵⁸,⁷⁶
The patient must be completely relaxed under general anesthesia, as
sedation or regional anesthesia is unlikely to provide sufficient
relaxation. With the elbow flexed approximately 90 degrees,
longitudinal traction is applied to the elbow while the forearm is
supinated (Fig. 16-29). If the radial head can
be palpated, gentle anterior-directed pressure may help slide the
radial head and neck over the coronoid process, allowing the proximal
radius and ulna to resume their normal configuration. As always, just
the right amount of force should be used; excessive force risks
iatrogenic fracture to the proximal radius. Successful closed reduction
should be confirmed on x-ray, and the elbow should be immobilized for
approximately 3 to 4 weeks with the forearm supinated and the elbow
flexed 90 to 100 degrees.

Most reported cases of radioulnar translocations have required open reduction.¹⁹,²⁰,³⁴,⁴⁰,⁴⁷,⁵⁸
A lateral approach provides adequate exposure to the translocation and
radial neck fracture if present. At surgery, the radial head and neck
are typically found trapped beneath the trochlea of the distal humerus.
Elbow extension tightens the biceps tendon, making reduction more
difficult. With the elbow flexed, a freer or joker elevator can be
placed beneath the radial head and neck facilitating delivery over the
coronoid process as the forearm is supinated. If present, a radial neck
fracture may now be treated in standard fashion. Internal fixation also
may be necessary for an unstable displaced fracture.

Harvey and Tchelebi⁴⁷
used an osteotomy of the proximal ulna to expose and reduce the radius
that was complicated by a postoperative ulnar nerve paralysis that
recovered completely over 2 months.

After successful closed or open reduction, the forearm
is immobilized for approximately 3 to 4 weeks with the forearm
supinated and the elbow flexed 90 to 100 degrees, followed by active
elbow range-of-motion exercises.

Longitudinal traction on the extended elbow is the usual mechanism of injury (Fig. 16-30).
Cadaver studies have shown that longitudinal traction on the extended
elbow can produce a partial slippage of the annular ligament over the
head of the radius and into the radiocapitellar joint, sometimes
tearing the subannular membrane. Displacement of the annular ligament
occurs most easily with the forearm in pronation. In this position, the
lateral edge of the radial head, which opposes the main portion of the
annular ligament, is narrow and round at its margin.⁷⁷,⁸⁵
In supination, the lateral edge of the radial head is wider and more
square at its margin, thereby restricting slippage of the annular
ligament. McRae and Freeman⁸⁹ demonstrated that forearm pronation maintained the displacement of the annular ligament.

Presumably, the annular ligament displaces proximally,
partially over the radial head in this condition. This anatomic finding
has been confirmed in numerous cadaver experiments.⁸⁵,⁸⁹,¹²⁰
After 5 years of age, the distal attachments of the subannular membrane
and annular ligament to the neck of the radius have strengthened
sufficiently to prevent its tearing and subsequent displacement.¹²⁰
Previously, the theory was proposed that the radial head diameter was
less in children than in adults and this contributed to subluxation of
the annular ligament. However, cadaver studies of infants, children,
and adults have shown that the ratio of the head and neck diameters is
essentially the same.¹¹⁸,¹²⁰ Griffin⁴³
suggested that the lack of ossification of the proximal radial
epiphysis in children less than 5 years of age made it more pliable,
thereby facilitating slippage of the annular ligament.

Amir et al.⁶
performed a controlled study comparing 30 normal children with 100 who
had pulled elbow syndrome. They found an increased frequency of
hypermobility or ligamentous laxity among children with pulled elbows.
Also, there was an increased frequency of hypermobility in one or both
parents of the involved children compared with noninvolved children,
suggesting that hypermobility could be a factor predisposing children
to this condition.

Thus, the most widely accepted mechanism is that the
injury occurs when the forearm is pronated, the elbow extended, and
longitudinal traction is applied to the patient’s wrist or hand (see Fig. 16-30).⁸⁵,⁸⁹,¹²²
Such an injury typically occurs when a young child is lifted or swung
by the forearm or when the child suddenly steps down from a step or off
a curb while one of the parents is holding the hand or wrist.

Unusual Mechanisms. Newman⁹⁸
reported that 5 of 6 infants under 6 months of age with a pulled elbow
sustained the injury when rolling over in bed with the extended elbow
trapped under the body. It was believed that this maneuver, especially
if the infant was given a quick push to turn over by an older sibling
or a parent, provided enough longitudinal traction to displace the
annular ligament proximally.

The history is usually that of an episode of a
longitudinal pull on the elbow of the young child. The initial pain
usually subsides rapidly, and the child does not appear to be in
distress except that he or she is reluctant to use the involved
extremity. The upper extremity is typically held at the side with the
forearm pronated. A limited painless arc of flexion and extension may
be present; however, any attempt to supinate the forearm produces

pain
and is met with resistance. Although there is no evidence of an elbow
effusion, local tenderness may be present over the radial head and
annular ligament. In some patients, the pain may be referred proximally
to the shoulder but most complain of pain distally toward the wrist.⁶,⁵⁶

Unfortunately, the classic history is not always present.²²,¹⁰⁵,¹⁰⁸,¹¹⁹,¹²² In some studies 33% to 49% of patients had no clear history of longitudinal traction to the elbow.¹¹⁹,¹²²
In patients without a witnessed longitudinal traction injury, other
causes, such as occult fracture or early septic arthritis, must be
carefully ruled out.

No other associated injuries have consistently been linked with pulled elbow syndrome.

There is no commonly used classification system for this
condition because there is essentially only one type of pulled elbow
syndrome.

Should x-rays be taken of every child before
manipulation is attempted? If there is a reliable history of traction
to the elbow, the child is 5 years of age or younger, and the clinical
findings strongly support the diagnosis, x-rays are not necessary.⁶,²²,¹⁰⁸,¹²⁰,¹³⁷
If, however, there is an atypical history or clinical examination,
x-rays should be obtained to be certain there is not a fracture before
manipulation is attempted.

Anteroposterior and lateral x-rays usually are normal,¹⁴,²²,⁴³,¹⁰⁸,¹²⁰,¹²²,¹²⁷
but subtle abnormalities may be present. Normally, the line down the
center of the proximal radial shaft should pass through the center of
the ossification center of the capitellum (radiocapitellar line).³⁹,¹²⁷
Careful review of x-rays may demonstrate the radial capitellar line to
be lateral to the center of the capitellum in up to 25% of patients.³⁹,¹²⁷
Determination of this subtle change requires a direct measurement on
the x-ray. Interestingly, the pulled elbow can be reduced by the
radiology technician because the elbow x-rays are usually taken with
the forearm supinated. The subluxation is reduced inadvertently when
the technician places the forearm into supination to position it for
the x-ray. Bretland¹³ suggested that
if the best x-ray that can be obtained is an oblique view with the
forearm in pronation, pulled elbow syndrome is the likely diagnosis.

Ultrasonography. When the diagnosis is not evident, ultrasonography may be helpful,⁶⁹,⁷⁷ although not always reliable.¹²¹
The diagnosis is made by demonstrating an increase in the echonegative
area between the articular surfaces of the capitellum and the radial
head and increased radial capitellar distance. Kosuwon et al.¹¹⁸
found that this distance is normally about 3.8 mm with forearm
pronated. With a subluxated radial head, this measured 7.2 mm. A
difference of 3 mm between the normal and affected sides, therefore,
suggests radial head subluxation.

Virtually all annular ligament subluxations are
successfully treated by closed reduction. This is usually best done by
forearm supination.²²,⁴³,⁵⁶,⁷⁵,¹⁰⁸,¹²²,¹²⁶
Some have recommended that supination be done with the elbow flexed,
and others have found that supination alone with the elbow extended can
effect a reduction. In many patients, a snapping sensation can be both
heard and palpated when the annular ligament reduces (Fig. 16-31). Macias et al.⁷⁵
reported that hyperpronation was more successful than supination in a
randomized study. Reduction was successful in 40 of 41 patients (98%)
in the hyperpronation group, compared with 38 of 44 patients (86%) in
the supination group. They concluded that the hyperpronation technique
was more successful, required fewer attempts, and was often successful
when supination failed. Generally, a full arc of supination to
pronation of the forearm, with elbow flexion and extension, will reduce
all pulled elbows.

The value of immobilizing the elbow following reduction has been debated. Taha¹³⁴
reported a decreased rate of recurrence during the 10 days following
reduction if the elbow was splinted in a flexed supinated position for
2 days following reduction. Salter and Zaltz¹²⁰ recommended the use of a sling, mainly to prevent the elbow from being pulled a second time. Kohlhaas and Roeder⁶⁸
recommended a T-shirt technique for flexed elbow stabilization in very
young children. This provided adequate immobilization without the use
of a sling by pinning the sleeve of the long sleeve T-shirt to the
opposite chest. In general, after a successful closed reduction of a
first time annular ligament

subluxation,
immobilization of the extremity is not necessary if the child is
comfortable and using the arm normally. After the reduction, it is
important to explain to the parents the mechanism of injury and to
emphasize the need to prevent longitudinal pulling on the upper
extremities. Picking the child up under the axillae and avoiding games
such as “ring around the roses” and involve longitudinal traction to
the arm are stressed. However, recurrence rate is high even with the
most diligent parents. Therefore, instruction in home reduction of the
pulled elbow is very useful and lessens visits to the emergency room
and primary care physician.

Even if untreated, most annular ligament subluxations
reduce spontaneously. There are no reported cases of long-term sequelae
of untreated annular ligament subluxation. Therefore, open reduction is
rarely if ever indicated for annular ligament subluxation. An
indication for surgery might be the chronic, symptomatic, irreducible
subluxation.¹³⁷ In such a circumstance, the annular ligament must be partially transected to achieve reduction.

It should never be assumed that an unwitnessed fall has
resulted in annular ligament subluxation. Such an injury mechanism is
much more likely to result in a fracture (possibly occult) about the
elbow.

The reported incidence of recurrent subluxation has varied from 5% to 39%.²²,⁴³,⁵⁶,¹⁰⁸,¹²²,¹²⁶,¹³⁵ Children 2 years of age or younger appear to be at greatest risk for recurrence.¹²²,¹³⁷
Recurrent subluxations usually respond to the same manipulative
procedure as the initial injury. They eventually cease after 4 to 5
years when the annular ligament strengthens and ligament laxity
lessens. Recurrences do not lead to any long-term sequelae. If
recurrent annular ligament subluxation significantly impacts a
patient’s quality of life because of pain or limited activity,
immobilization in an above-elbow cast with the forearm in supination or
neutral position for 2 to 3 weeks is usually effective at preventing
recurrence.