Epidemiology and Anatomy
• Capitellar fractures account for 0.5-1% of all elbow
fractures and 6% of all distal humeral fractures.
• More common in females than in males.
• This is thought to be secondary to a greater carrying
angle and an increased possibility of osteoporosis in
• As the center of rotation of the capitellum is 12–15
mm anterior to the humeral shaft, it is vulnerable to
shearing fractures in the coronal plane.
• Capitellum Fractures
Occurs in a coronal
• Anterior part of the
capitellum is sheared
off and displaced
the capitellum from the
• The diagnosis is confirmed by the lateral
view of the joint which will show the
semilunar fragment displaced anteriorly and
• An effusion within the elbow joint together
with displacement of fat pads suggests either
a capitellum fracture or nondisplaced frx of
• The AP view may appear normal but in the AP
view if the subchondral line is traced from medial
to lateral, it will show haziness or discontinuity in
the lateral portion.
Normal Alignment of
the distal humerus and
A line drawn along the
anterior border of the
distal humerus (green)
should intersect the
long axis of the
capitellum (purple) in
the mid third (area
shaded light green)
• For a true lateral view the shoulder should be
at the level of the elbow.
If the shoulder is higher than the elbow, the
radius and capitellum will project on the ulna.
Plain X-ray of elbow
• The wrist should be
higher than the elbow
to compensate for the
normal valgus position
of the elbow.
The hand should be
with the 'thumb up'.
• Most apparently isolated capitellar fractures are
more complex than they initially appear.
• Computed tomography - particularly 3D CT - can help
define the fracture anatomy and facilitate planning of
• CT scans with three-dimensional reconstruction
help in assessment of the size and the
orientation of the fracture fragment and in
guiding the preoperative planning.
• Radiographs are insufficient
• Sometimes the appearance is more complex,
but it can be difficult to understand the
fracture pattern on standard radiographs,
particularly if a cast obscures the view.
• Radial head fractures (20%).
• Posterior dislocation of the
• Disruption of the medial (ulnar)
collateral ligament, the
interosseous membrane, and the
distal radioulnar joint.
Bryan and Morrey Classification
(with McKee modification)
Type I (Hahn- Steinhal
Large osseous piece of the capitellum
Type II (Kocher-Lorenz
Shear fracture of articular cartilage
Articular cartilage separation with
very little subchondral bone attached
Type III (Broberg-
Type IV (McKee
Coronal shear fracture
that includes the
capitellum and trochlea
• Because of the rarity of capitellar
fractures, controversies exist regarding
the most appropriate treatment.
• The fracture fragment is intra-articular
and requires treatment and reduction
to reestablish normal elbow motion.
• Difficulty arises from the varying
sizes of the fracture fragment and
from the amount of suitable
subchondral bone that is present to
achieve stable fixation and to allow
early elbow motion.
• Failure of adequate intervention may
result in an incongruous joint, as well
as in stiffness, instability, and chronic
Type I (Hahn-Steinthal fracture):
• Shear fracture involving a large osseous portion of
the capitellum in the coronal plane and less than
half of the lateral part of the trochlea.
• Fracture hinges anteriorly between radial head and
radial fossa producing a block to flexion.
• Radiographs: double arc sign seen on lateral views.
• Oblique views may be required to visualize the main
Double Arch sign
Open reduction and internal fixation:
• Lateral/ Anterolateral approach.
• Internal fixation of capitellum fractures
requires near anatomic reduction and
• Options for fixation
4mm partially threaded screws
Fixed with a Herbert
screw with the lateral
Dissect between the triceps muscle posteriorly and the
brachioradialis and extensor carpi radialis longus muscles
There is no Internervous plane:
Between the Triceps (radial n.) and Brachioradialis (radial n.)
Internervous plane. Proximally,
the plane is between the
nerve) and the brachioradialis
(radial nerve); distally, it is
between the brachioradialis and
the pronator teres (median
• Fixation by partially threaded screws
provide strong interfragmentary
compression and stable fixation which allows
• The posterior-to-anterior screws have been
found to be biomechanically superior to
• This is because countersinking needed with
AP screws damage the subchondral bone
and compromise the stability.
• PA screws also have the advantage of
leaving the articular cartilage intact.
• Fixation by variable pitch headless
screws such as Accutrak is
biomechanically superior to PA lag
• The major advantage of all headless
screws, is that the screw is placed within
the bone without any outside
prominence, avoiding impingement.
Herbert screw fixation of capitellar fractures
Amr S. Elgazzar
Egyptian Orthopedic Journal 2013, 48:335-338
Open reduction and internal fixation with Herbert screws
leads to minimal articular damage and rigid fixation as well as
early mobilization. Encountering a free capitellar fragment
and nonunion should not discourage the use of internal
fixation, as avascular necrosis is less likely to occur with good
fixation and early mobilization.
Open Reduction And Internal Fixation Of Capitellar Fractures With Headless
David E. Ruchelsman et al
J Bone Joint Surg Am. 2008;90:1321-1329
Good to excellent outcomes with functional ulnohumeral motion can
be achieved following internal fixation of these complex fractures.
Type-IV fractures often are associated with metaphyseal comminution
or a radial head fracture and may require supplemental fixation.
The fixation of type-1 capitellum fractures with 2 to 3
cannulated cancellous screws inserted postero-
anteriorly achieved excellent functional outcome.
Cannulated cancellous screw fixation for capitellum fractures in
Kee Leong Ong, Arjandas Mahadev
Journal of Orthopaedic Surgery 2011;19(3):346-9
50 year old male patient with
Capitellum and radial head fracture
Type II (Kocher-Lorenz fracture)
• Fracture involves a shell of the articular
cartilage with a thin layer of bone.
• Fragment is usually displaced anteriorly.
• Fragment excision is the recommended
• May be difficult to fix as the fragment has only
a thin shell of bone. Fixation by headless
screws may be done if feasible, otherwise
excision may have to be done.
European journal of trauma 2003
Rashid Khan et al
Treatment of Type 2 Capitellum fracture with K wire
Type III (Broberg and Morrey)
• Comminuted fractures
• Difficult to reduce anatomically
• Need excision of fragment
65 year old patient with Comminuted
Type IV (McKee modification)
• Fracture that includes more than the lateral
half of the trochlea.
• Fixation with non-cannulated AO screws
through extended lateral Kocher's approach is
the recommended treatment
Outcome of surgical treatment of type IV capitellum fractures
Chinese Journal of Traumatology 2012;15(4):201-205
Ajay Pal Singh*, Ish Kumar Dhammi, Vipul Garg and Arun Pal Singh
In Type 4 Capitellum Fractures, a good
functional outcome can only be achieved with
open reduction and stable internal fixation
followed by early mobilization.
19 year old male patient with Capitellum and Trochlea fracture
The lateral image shows the ‘‘double-arc’’ sign (arrows) that is
pathognomonic for a coronal shear fracture of the capitellum
with medial extension through the trochlea.
Treated by anterior approach using two antero
posterior Herbert screws
• Nonunion (1-11% with ORIF)
• Ulnar nerve injury
• Heterotopic ossification (4% with ORIF)
• AVN of capitellum
• Nonunion of olecranon osteotomy
–Posterior splint immobilization for < 3 weeks
•Non-displaced Type I and Type II fractures (<1 mm
–Open reduction and internal fixation
•Displaced Type I fractures (>1mm), and all Type III and
Type IV fractures
•(In Type II fractures excision/ fixation depending on the
Fragment excision :
– displaced (>2mm) Type II fractures
– displaced (>2mm) Type III fractures
Total elbow arthroplasty:
Unreconstructable capitellar fractures in elderly
patients with associated medial column instability
To take home ….
• Capitellum Fractures though rare, should not be
missed. A proper X-ray and CT is mandatory
• Anatomical reduction with a headless screw is ideal
in most of the situations.
• Approach most commonly lateral, rarely an anterior
or posterior approach may be necessary.