- SourceAvailable from: Anirudh Gadgil[Show abstract] [Hide abstract]
ABSTRACT: Coronoid process fractures are reported to occur from avulsion by the brachialis muscle or to be associated with elbow dislocations. We report a rare case of coronoid process fracture due to avulsion by the anterior bundle of the medial collateral ligament rendering the elbow unstable. In children, small fracture fragments of the coronoid process (types 1 & 2) are in reality often much larger but the actual size is not appreciated radiographically, as the coronoid process contains considerable amounts of cartilage. If the fragment is seen to be significantly displaced it may have resulted from avulsion by important structures such as the medial collateral ligament and open reduction is required to stabilise the elbow.Acta orthopaedica Belgica 11/2002; 68(4):396-8. · 0.57 Impact Factor
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ABSTRACT: Regan and Morrey proposed a 3-type coronoid fracture classification observing that the incidence of concommitant elbow dislocation was proportional to fragment size. Elbow instability associated with coronoid fractures presumably is related to disrupted bony architecture and ineffective stabilizers attached to the free fragment. Twenty cadaveric elbows were dissected, measuring medial collateral ligament, anterior capsule, and brachialis muscle insertion loci on the coronoid. Radiographs were taken after radiopaque labeling of the stabilizer insertions. The anterior bundle of the medial collateral ligament insertion averaged 18.4 mm dorsal to the coronoid tip. Only in Type III fractures would it be attached to the free fragment. The capsule inserted an average of 6.4 mm distal to the coronoid tip. Rarely should Type I fractures result from a capsular avulsion, because only 3 of 20 specimens had the capsule inserting on the tip. The brachialis had a musculoaponeurotic insertion onto the elbow capsule, coronoid, and proximal ulna. The bony insertion averaged 26.3 mm in length, with its proximal margin averaging 11 mm distal to the coronoid tip. In only Type III fractures is the fragment large enough to include the brachialis bony insertion.Clinical Orthopaedics and Related Research 12/1995; · 2.88 Impact Factor
Article: Complex elbow instability.[Show abstract] [Hide abstract]
ABSTRACT: This article attempts to outline the most current relevant literature regarding diagnosis, pathoanatomy, and treatment options for complex elbow instability. Specific attention is directed toward unique injury patterns, important biomechanical principles, and recent clinical outcome studies. Directions for future research are suggested.Hand Clinics 03/2008; 24(1):39-52. · 1.07 Impact Factor
Ravi Gupta, Amit Kumar, Tahir Ansari, Ratnav Ratan
Coronoid fractures usually occur as a part of unstable elbow dislocations1; however
these can occur in isolation as Brachialis avulsion injury.2 Traditionally, large coronoid
fracture fragments and the small fragments causing instability require fixation and the
small fragments causing no instability are managed conservatively. With increasing
understanding of the contribution of the coronoid to stability of the elbow, the trend is
increasingly towards operative stabilization of these injuries and initiation of early,
protected range-of-motion program to avoid stiffness at elbow. Since it is a part of
complex bony and soft tissue injury, the management of these injuries requires a complete
diagnosis as to whether the coronoid fracture is an isolated injury or is a part of a
complex injury which requires management of bony as well as soft tissue structures.
The elbow is an inherently stable joint consisting of articulations between the humerus,
ulna and radius; that has both rotational and hinge motion. The trochlea of the humerus
articulates with the trochlear notch of the proximal ulna to form the hinge while the
radial head articulates with the capitellum and the radial notch of the ulna to create a
joint for rotational motion. The distal humerus has coronoid fossa anteriorly that
accommodates the coronoid process during extreme flexion (Fig. 10.1) while posteriorly
there is olecranon fossa that accommodates the olecranon process during the extreme
extension. The coronoid process provides structural stability to elbow joint against
posterior displacement by acting as an anterior buttress3 (Fig. 10.1). Approximately
50% of the elbow stability comes from the congruent bony articulation between the
trochlea of humerus and coronoid facet of ulna.4
The coronoid process gives attachment to the anterior capsule of the elbow joint
close to its tip, insertion of brachialis muscle just distal to capsule (Fig. 10.2) and insertion
of the medial ulnar collateral ligament (MUCL) on the sublime tubercle on the medial
side;3,5 (Figs 10.3 and 10.4) thus contributing further to stability of the elbow joint.
Coronoid fractures account for about 1 to 2% of all elbow fractures and are associated
in 2 to 15% of patients with dislocation.6-8 They also occur as a part of a complex injury,
Figure 10.1: Frontal view of the bony anatomy of elbow
Figure 10.2: Important soft tissue attachments
contiguous to olecranon
Figure 10.3: Stabilizers of elbow joint on lateral aspect
Figure 10.4: Stabilizers of elbow joint on medial
known as ‘terrible triad of the elbow’9-11 that constitutes of elbow dislocation, radial
head fracture, and coronoid process fracture. In children, coronoid fractures have a
bimodal age distribution, with peaks at age 8-9 years and at age 12-14 years.12 Coronoid
fractures in children are often associated with elbow dislocations, olecranon fractures,
medial epicondyle fractures, or lateral condyle fractures.
Mode of Injury
Fracture of coronoid process take place usually as a part of elbow dislocation which
commonly is caused by a fall on the elbow or outstretched hand.10,13-15 The injury can
take place during motor vehicle accidents, sports injuries, activities of daily living or
even at work.13,15 It is a high energy injury associated with severe soft tissue damage.16
The mechanisms of injury of coronoid fracture consist of axial loading of the elbow
in extension causing shearing off of the coronoid by trochlea during posterior elbow
dislocation and/or the avulsion of the coronoid tip by the pulling force of the
When there is component of valgus and posterior-lateral rotatory force in addition
to this axial loading, postero-lateral rotational instability results. The forced supination
of forearm away from humerus first damages lateral collateral ligament and there can
be associated fracture of radial head, fracture of coronoid and posterior dislocation of
elbow; the terrible triad (Fig. 10.5). The MUCL is the last structure to be damaged in
this injury pattern.20
On the contrary if there is a valgus and postero-medial component to with this axial
loading, it causes fracture of antero-medial facet of coronoid which may be associated
with LCL injury or additional fracture to base of coronoid.1,2,21
Isolated valgus instability of the elbow can be found in throwing athletes (e.g.
baseball, javelin) due to rupture or attenuation of the medial ulnar collateral ligament
(MUCL);5 however it is the radial lateral collateral ligament which is more frequently
associated with traumatic elbow instblity.1,22
This injury may present as an isolated injury or more commonly as a part of elbow
dislocation. The patient usually has history of fall on outstretched hand with hyper-
extension and twisting forces at the elbow. There is pain, tenderness, and swelling
around the elbow. When there is an isolated coronoid fracture and sometimes after
Figure 10.5: Terrible triad of elbow
spontaneous relocation of associated elbow dislocation, these clinical signs are not
present.6,23 Varus or valgus stress tests and range of motion may demonstrate pain and
Neurovascular injury although rare with isolated coronoid fracture, can occur due
to associated injuries and should be ruled out by doing a proper clinical examination.
Radiographs of the elbow in the anteroposterior (AP), lateral, and, if required, oblique
views should be obtained to ascertain clearly the extent of bony injury. Oblique views
are especially important in minimally displaced fractures, because in a true lateral
view of the elbow, the radial head overlaps the coronoid, thus coronoid fractures may
be confused with radial head fractures.24,25 To avoid this problem, Greenspan and
Norman described the radiocapitellar view (Figs 10.6 and 10.7).26,27 This separates the
radial head from the coronoid and provides clear visualization of coronoid, radial head,
capitello-radial and trochleo-ulnar joints. Sometimes Plain radiographs are unable to
completely demonstrate the extent of associated injuries and CT scan or MRI is useful.
Figure 10.6: Method to obtain radio-capitellar view
Figures 10.7A to C: Radiocapitellar view. What appears to be an isolated fracture of capitellum
on anterio-posterior and true lateral view demonstrates an associated fracture of coronoid on
Regan and Morrey classified coronoid fractures into 3 types:8
• Type I: Tip of the coronoid
• Type II: More than tip but less than 50% of coronoid
• Type III: More than 50%.
There are A and B subtypes in each category indicating absence and presence of
associated dislocation respectively.
O’Driscoll described a new classification system as follows:28
• Type 1: Tip fracture,
• Type 2: Anteromedial facet fracture,
• Type 3: Basal fracture involving at least 50% of height of coronoid.
All the 3 types are further divided into subtypes depending upon severity of the
injury (Fig. 10.8). This classification system considers the injury pattern and thus helps
in diagnosis of associated injuries and planning of treatment.28
Treatment and Surgical Indications
Aim of surgery for any injury around elbow should be to achieve stability and start
early range of motion exercise. Being an articular fracture, congruent reduction at the
time of surgery should be ensured. Role of coronoid as important stabilizer of elbow
has been shown in recent studies.10,28,29 The injuries which pose difficulty in management
are the terrible triad, varus-postero-medial injury, and olecranon fracture-dislocations
with associated coronoid fractures.28 In all these injuries management of cronoid fracture
is critical for elbow stability.
The stabilizing function of the coronoid process under axial load to the elbow has
been reported to have no significant difference; at any flexion position in posterior
axial displacement between intact elbows and elbows in which 50% or less of the
coronoid process was fractured (Regan and Morrey types 1 and 2) (P = .43).30 Differences
in posterior axial displacement were significant across all flexion positions between
intact elbows and elbows in which more than 50% of the coronoid process was fractured
(Regan and Morrey-type 3, O’Driscoll-Basal type) (P = .006). Thus for isolated coronoid
fractures Regan and Morrey type 1 and type 2 fractures can be managed conservatively.
However since coronoid fracture rarely occurs as isolated injury, size of the fractured
fragment should not be the sole criteria in planning treatment of these fractures. The
Figure 10.8: Types of coronoid fractures (after O‘Driscoll28)
antero-medial fascet of coronoid, basal coronoid fracture, associated Olecranon and
radial head fracture should be fixed. Among the soft tissue component LCL which is
usually avulsed from lateral epicondyle should be repaired and MUCL is expected to
heal properly without repair in an otherwise stable elbow.29,31 In addition a displaced
coronoid fracture that presents with a block to elbow motion is a definite indication for
POSITION AND ANESTHESIA
Coronoid is usually fixed through a posteromedial approach in a lateral position
(Figs 10.9 and 10.10) preferably under general anesthesia.
EXPOSURE OF FRACTURE
The coronoid can be approached posteromedially through a posterior midline incision
after lifting the ulnar origin of the extensor carpi ulnaris (ECU) subperiosteally.
Figure 10.9: Posterior approach to the coronoid: lateral decubitus position with a pillow under
Figure 10.10: Posterior approach to the coronoid: after prepping and drapping
In cases of a Monteggia fracture-dislocation, the coronoid may be approached
through the interval between the ECU and the anconeus laterally and the flexor carpi
ulnaris (FCU) medially. The radial head may be approached between the anconeus
medially and the ECU laterally. This will help prevent formation of a synostosis between
the radius and the ulna.
Anatomical reduction of a large coronoid process fracture is important for elbow joint
stability and congruity. This is particularly true, when the coronoid fracture is part of a
comminuted olecranon fracture. Reduction may be visualized through the medially
extended posterior incision, through the olecranon fracture site (Fig. 10.12). Alignment
must be checked with satisfactory x-rays or image intensifier.
After exposing the fracture site and cleaning the edges, the fragment is anatomically
reduced. The fracture is stabilized initially with a large clamp or by Kirschner wire
(K-wire) fixation. Definitive fixation can then be achieved with a small plate or with
screws. Precontoured coronoid plates are now available .The primary role of the plate
is to provide a buttress against posterior subluxation of the ulna in relation to the
humerus (i.e. push plate) .Coronoid may also befixed by means of an interfragmentary
screw (from posterior to anterior, or from anterior to posterior if the fragment is small
or osteoporotic) (Fig. 10.13).
Figure 10.11: Radial head being approached between
the anconeus medially and the ECU laterally
Figure 10.12: Fixation of a coronoid fracture combined with a
transolecranon fracture. After fixing coronoid, olecranon is fixed
with another plate posteriorly.
The fracture may also be stabilized using heavy nonabsorbable sutures or suture
anchors32,33 (Fig. 10.14).
The results from one study noted that suture lasso fixation of coronoid fractures for
terrible triad injuries results in fewer complications and greater stability compared
with screw or suture anchor fixation techniques. A higher rate of implant failure was
noted with internal screw fixation, while the suture anchor technique resulted in a
higher rate of malunion and nonunion.34
In patients with highly comminuted coronoid fractures which is large enough to
compromise stability and not fixable; reconstruction using a piece of the radial head
(Esser technique) or a piece of the olecranon (Moritomo technique) has been described.38
Intraoperative test of stability should be performed with different authors describing
stability up to 45 to 30 degree of flexion as acceptable.29,36
After the surgery, the elbow is immobilized at 90° of flexion in a well-padded posterior
splint. The elbow is immobilized for about a week, and then a protected immobilization
program in a hinged orthosis is initiated, which prevents varus-valgus stresses on the
elbow. Brace use is continued for approximately 4-6 weeks to allow the ligaments to
Osteoarthritis, myositis ossificans, parasthesia, stiffness and instability are the most
common complications associated with coronoid fractures.
Osteoarthritis occurs due to incongruent fixation of coronoid especially the
anteromedial facet and can be avoided by ensuring anatomical reduction. Myositis
ossificans is associated with any injury or surgery around elbow, the authors prefer to
use indomethacin (75 mg PO) for 3 weeks following the surgery to prevent this.
Paraethesias in the ulnar nerve distribution can be avoided by anterior transposition
whenever necessary. The Early mobilization is important to prevent stiffness and painful
loss of function.2,10,15,17,23,37,38 Unrecognized or untreated LCL injury is the most
common cause of post-traumatic instability; however attenuated or torn MUCL can be
the cause in throwing athletes.
Figure 10.13: Fixation of coronoid using postero anterior
Figure 10.14: Illustration of suture technique for fixation of a
small coronoid fracture
A 38 -year-old man presented with radial head fracture with communited olecranon
fracture extending into the coronoid with a communited radial head fracture. He was
operated via a posterior approach in lateral postion. Open reduction was done with a
reconstruction plate with a posteroanterior screw into coronoid through the plate along
with radial head replacement. His pre and postoperative X-rays are shown in
Figure 10.15. At the end of 3 months he had an excellent range of motion of elbow and
a satisfactory outcome.
Figure 10.15: Preoperative Xrays and CT showing a
communited olecranon fracture extending into the
coronoid with a communited radial head fracture for
which open reduction of coronoid and olecranon done
with a posteroanterior screw through the plate along with
radial head replacement
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