capitellum fractures

CAPITELLUM FRACTURES

Dr. Apoorv JainD’Ortho, DNB Ortho

drapoorvjain23@gmail.com+91-9845669975

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 females.

• 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 plane.• Anterior part of the

capitellum is sheared off and displaced proximally separating the capitellum from the lateral column.

• The diagnosis is confirmed by the lateral view of the joint which will show the semilunar fragment displaced anteriorly and superiorly.

• An effusion within the elbow joint together with displacement of fat pads suggests either a capitellum fracture or nondisplaced frx of radial head.

Plain Radiographs

• 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

Capitellum

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 the surgery.

• 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.

Associated injuries

• Radial head fractures (20%).• Posterior dislocation of the

elbow.• 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 fracture):Large osseous piece of the capitellum involved

Type II (Kocher-Lorenz fracture):Shear fracture of articular cartilageArticular cartilage separation with very little subchondral bone attached

Type III (Broberg-Morrey fracture):Severely comminutedMultifragmentry

Type IV (McKee modification):Coronal shear fracture that includes the capitellum and trochlea

Management • 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 pain.

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

fracture line Double Arch sign

Open reduction and internal fixation:

• Lateral/ Anterolateral approach.• Internal fixation of capitellum fractures

requires near anatomic reduction and compression.

• Options for fixationHeadless screws4mm partially threaded screwsKirschner wiresAbsorbable pins

Fixed with a Herbert screw with the lateral approach

Lateral Approach

Dissect between the triceps muscle posteriorly and the brachioradialis and extensor carpi radialis longus muscles

anteriorly

There is no Internervous plane: Between the Triceps (radial n.) and Brachioradialis (radial n.)

Anterolateral Approach

Internervous plane. Proximally, the plane is between the

brachialis (musculocutaneous nerve) and the brachioradialis

(radial nerve); distally, it is between the brachioradialis and

the pronator teres (median nerve).

• Fixation by partially threaded screws provide strong interfragmentary compression and stable fixation which allows early mobilization.

• The posterior-to-anterior screws have been found to be biomechanically superior to anterior-to-posterior screws.

• 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 screws.

• 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 fracturesAmr 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 Screws

David E. Ruchelsman et alJ 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 adolescents

Kee Leong Ong, Arjandas MahadevJournal of Orthopaedic Surgery 2011;19(3):346-9

50 year old male patient with Capitellum and radial head fracture

3 months post op

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

treatment.• 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 2003Rashid Khan et al

Treatment of Type 2 Capitellum fracture with K wire fixation

Type III (Broberg and Morrey)• Comminuted fractures• Difficult to reduce anatomically• Need excision of fragment

65 year old patient with Comminuted Capitellum fracture

Presented to us with

this picture

Pre-op

Post-op

Courtesy: Dr. Dharmapal

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 fracturesin adults

Chinese Journal of Traumatology 2012;15(4):201-205Ajay 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 fractureThe 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

Complications

• Nonunion (1-11% with ORIF)• Ulnar nerve injury• Heterotopic ossification (4% with ORIF)• AVN of capitellum• Nonunion of olecranon osteotomy

Treatment SummaryNon-operative:–Posterior splint immobilization for < 3 weeks–Indications:•Non-displaced Type I and Type II fractures (<1 mm displacement)

Operative:–Open reduction and internal fixation–Indications:•Displaced Type I fractures (>1mm), and all Type III and Type IV fractures•(In Type II fractures excision/ fixation depending on the fracture pattern)

Fragment excision : Indications– displaced (>2mm) Type II fractures– displaced (>2mm) Type III fractures

Total elbow arthroplasty: Indications

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.