DISTAL HUMERUS fractures

EPIDEMIOLOGY

This is a relatively uncommon injury, comprising approximately 2% of all fractures and one-third of all humerus fractures.

Incidence of distal humerus fractures in adults is 5.7 per 100,000 per year.

Distal humerus fractures have a bimodal age distribution, with peak incidences occurring between the ages of 12 and 19 years in men and 80 years and older in women.

Greater than 60% of distal humerus fractures in the elderly occur from low-energy injuries, such as a fall from standing height.

Extra-articular fractures (40%) and bicondylar intra-articular fractures of the distal humerus (37%) are the most common fracture patterns.

Extension-type supracondylar fractures of the distal humerus account for >80% of all supracondylar fractures in children.

ANATOMY

Distal humerus may be conceptualized as medial and lateral “columns,” each of which is roughly triangular in shape and composed of an epicondyle, or the nonarticulating terminal of the supracondylar ridge, and a condyle, which is the articulating unit of the distal humerus (Fig. 17.1).

Articulating surface of the capitellum and trochlea projects distal and anterior at a 40- to 45-degree angle. The center of the arc of rotation of each condyle’s articular surface lies on the same horizontal axis; thus, malalignment of the relationships of the condyles to each other changes their arc of rotation, thus limiting flexion and extension (Fig. 17.2).

The trochlear axis compared with the longitudinal axis of the humerus is 4 to 8 degrees of valgus.

The trochlear axis is 3 to 8 degrees internally rotated.

The intramedullary canal of the humerus ends 2 to 3 cm above the olecranon fossa.

MECHANISM OF INJURY

Most low-energy distal humeral fractures result from a simple fall in middle-aged and elderly women in which the elbow is either struck directly or is axially loaded in a fall onto the outstretched hand.

Motor vehicle and sporting accidents are more common causes of injury in younger individuals.

CLINICAL EVALUATION

Signs and symptoms vary with degree of swelling and displacement; considerable swelling frequently occurs, rendering landmarks difficult to palpate. However, the normal relationship of the olecranon, medial, and lateral condyles should be maintained, roughly delineating an equilateral triangle.

Crepitus with range of motion and gross instability may be present; although this is highly suggestive of fracture, no attempt should be made to elicit it because neurovascular compromise may result.

A careful neurovascular evaluation is essential because the sharp, fractured end of the proximal fragment may impale or contuse the brachial artery, median nerve, or radial nerve.

Serial neurovascular examinations with compartment pressure monitoring may be necessary with massive swelling; cubital fossa swelling may result in vascular impairment or the development of a volar compartment syndrome resulting in Volkmann ischemia.

RADIOGRAPHIC EVALUATION

Standard anteroposterior (AP) and lateral views of the elbow should be obtained. Oblique radiographs may be helpful for further fracture definition.

Traction radiographs may better delineate the fracture pattern and may be useful for preoperative planning.

In nondisplaced fractures, an anterior or posterior “fat pad sign” may be present on the lateral radiograph, representing displacement of the adipose layer overlying the joint capsule in the presence of effusion or hemarthrosis.

Minimally displaced fractures may result in a decrease in the normal condylar shaft angle of 40 degrees seen on the lateral radiograph.

Because intercondylar fractures are almost as common as supracondylar fractures in adults, the AP (or oblique) radiograph should be scrutinized for evidence of a vertical split in the intercondylar region of the distal humerus.

Computed tomography is often used to delineate the fracture pattern, amount of comminution, and intra-articular extension.

CLASSIFICATION

Descriptive

Supracondylar fractures

• Extension type

• Flexion type

Transcondylar fractures

Intercondylar fractures

Condylar fractures

Capitellum fractures

Trochlea fractures

Lateral epicondylar fractures

Medial epicondylar fractures

Fractures of the supracondylar process

Orthopaedic Trauma Association Classification of Fractures of the Distal Humerus

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

GENERAL TREATMENT PRINCIPLES

Anatomic articular reduction

Stable internal fixation of the articular surface

Restoration of articular axial alignment

Stable internal fixation of the articular segment to the metaphysis and diaphysis

Early range of elbow motion

SPECIFIC FRACTURE TYPES

Extra-Articular Supracondylar Fracture

This results from a fall onto an outstretched hand with or without an abduction or adduction force.

The majority are extension patterns with a minority being flexion types.

Treatment

Nonoperative

This is reserved for nondisplaced or minimally displaced fractures, as well as for severely comminuted fractures in elderly patients with limited functional ability.

A posterior long arm splint is placed in at least 90 degrees of elbow flexion if swelling and neurovascular status permit, with the forearm in neutral.

Posterior splint immobilization is continued for 1 to 2 weeks, after which range-of-motion exercises are initiated in a hinged brace. The splint or brace may be discontinued after approximately 6 weeks, when radiographic evidence of healing is present.

Frequent radiographic evaluation is necessary to detect loss of fracture reduction.

Operative

Indications

• Displaced fractures

• Vascular injury

• Open fracture

• Inability to maintain acceptable reduction

  Patient positioning

Supine on a radiolucent table with arm over chest

• Quick and easy setup

• Good for multiply injured patients with multiple extremity involvement

• Requires assistant to hold arm during procedure

Lateral

• Allows good access to posterior arm and elbow without need for additional assistant

Prone

• Allows good access to posterior arm and elbow without need for additional assistant Image positioning

Image intensifier can be placed on same or opposite side of the injured extremity

Surgical approaches:

Triceps splitting approach

• Easy to perform

• Enables intact trochlear notch of proximal ulna to act as template to assist fracture reduction

• No need for additional hardware to reattach olecranon

• Can be converted to exposure necessary for total elbow replacement or olecranon osteotomy for increased articular exposure

• Affords limited articular exposure—usually used for extra-articular fractures

Paratricipital approach

• Easy to perform

• Uses windows on either side of the triceps to assess fracture reduction

• Can be converted to exposure necessary for total elbow replacement or olecranon osteotomy for increased articular exposure

• Has limited articular exposure compared to olecranon osteotomy

• Usually used for extra-articular fractures or if chance of conversion to elbow arthroplasty during surgery

Triceps reflecting anconeus pedicle (TRAP) approach

• Uses a proximally based triceps–anconeus flap

• Medial portion of flap is created by subperiosteal dissection from the subcutaneous border of the ulna

• Kocher interval is used to raise the anconeus muscle and develop the lateral portion of the flap

• Anconeus flap elevated and reflected proximally to expose the triceps insertion, which is also released

• Advantage is preservation of the neurovascular supply to the anconeus

• Soft tissue repair required to reattach the extensor mechanism

Bryan-Morrey approach

• Involves subperiosteal reflection of the triceps insertion from medial to lateral in continuity with the forearm fascia and anconeus muscle

• Although the triceps tendon insertion is detached, the extensor mechanism maintains its

  continuity as a single sleeve through its soft tissue attachments

• Extensor sleeve is repaired using drill holes or osseous anchors

• Used primarily for arthroplasty

Van Gorder approach (triceps tongue)

• Transection of triceps at musculotendinous junction (V–Y incision)

• Used for arthroplasty or fractures with complete/high-grade triceps tendon laceration

Olecranon osteotomy

• Most extensile approach

• Uses a transverse or apex distal, chevron-type osteotomy of the olecranon which exits in the so-called bare area of the trochlear groove

• Osteotomy is initiated with an oscillating saw and completed with an osteotome

• Osteotomy requires fixation using a tension band construct, an intramedullary screw/nail, or a plate.

  Implant options

Plate fixation

• Plate fixation is used on each column, either in parallel or 90 degrees from one another.

• Use of locked plates has gained in popularity and affords much better metaphyseal fixation than conventional nonlocked plates.

• Parallel plating has been shown to be biomechanically superior to orthogonal plating for distal

  fractures. Use of parallel plating allows for longer length screws directed from lateral to medial than a posterolateral plate in which screw length is limited by the anterior articular surface.

Total elbow replacement

• Indicated in elderly patients with a severely comminuted fracture of the distal humerus deemed unreconstructable

• Use of elbow arthroplasty requires lifelong restriction of 5 lb weight bearing in that arm

• Medial, triceps-sparing approach should be utilized, rather than an olecranon osteotomy, for exposure of the elbow joint.

Range-of-motion exercises should be initiated as soon as the patient is able to tolerate therapy.

Complications

Volkmann ischemic contracture (rare): This may result from unrecognized compartment syndrome with subsequent neurovascular compromise. A high index of suspicion accompanied by aggressive elevation and serial neurovascular examinations with or without compartment pressure monitoring must be maintained.

Loss of elbow range of motion: This is generally the rule following any fracture about the elbow.

Loss of extension due to callus formation in the olecranon fossa

Loss of flexion due to capsular contracture and/or H.O.

Heterotopic bone formation may occur.

Transcondylar Fractures

Occur primarily in elderly patients with osteopenic bone

Mechanism of Injury

Mechanisms that produce supracondylar fractures may also result in transcondylar fractures: a fall onto an outstretched hand with or without an abduction or adduction component or a force applied to a flexed elbow.

Treatment

Nonoperative

Indicated for nondisplaced or minimally displaced fractures or in elderly patients who are debilitated and functioning poorly.

Range-of-motion exercises should be initiated as soon as the patient is able to tolerate therapy.

Operative

Operative treatment should be undertaken for open fractures, unstable fractures, or displaced fractures.

Open reduction and plate fixation are the preferred treatment. Precontoured locked plates should be utilized in order to enhance fixation in this usually osteopenic fracture pattern.

Total elbow arthroplasty (semiconstrained) may be considered in the elderly patient with good preinjury functional status if fixation cannot be obtained.

Intercondylar Fractures

It is the second most common distal humeral fracture (next to extra-articular).

Comminution is common.

Fracture fragments are often displaced by unopposed muscle pull at the medial (flexor mass) and lateral (extensor mass) epicondyles, which rotate the articular surfaces.

Mechanism of Injury

Force is directed against the posterior aspect of an elbow flexed >90 degrees, thus driving the ulna into the trochlea.

Riseborough and Radin (Fig. 17.3)

Type I: Nondisplaced

Type II: Slight displacement with no rotation between the condylar fragments

Type III: Displacement with rotation

Type IV: Severe comminution of the articular surface

Classification

Orthopaedic Trauma Association Classification

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

Treatment

Treatment must be individualized according to patient age, bone quality, and degree of comminution.

Nonoperative

This is indicated for nondisplaced fractures, elderly patients with displaced fractures and severe osteopenia and comminution, or patients with significant comorbid conditions precluding operative management. Nonoperative options for displaced fractures include:

• Cast immobilization: This has few advocates; it represents the “worst of both worlds”— inadequate fracture reduction and prolonged immobilization.

• “Bag of bones”: The arm is placed in a collar and cuff with as much flexion as possible after

  initial reduction is attempted; gravity traction helps effect reduction. The idea is to obtain a painless “pseudarthrosis,” which allows for motion.

  Operative

Open reduction and internal fixation

• This is indicated for displaced reconstructible fractures.

• Goals of fixation are to restore articular congruity and to secure the supracondylar component.

• Methods of fixation include:

  • Interfragmentary screws

  • Dual plate fixation: one plate medially and another plate placed posterolaterally, 90 degrees from the medial plate or two plates on either column, 180 degrees from one another

Total elbow arthroplasty (cemented, semiconstrained): This may be considered in markedly

comminuted fractures and with fractures in osteoporotic bone.

Surgical exposures

• Described above

Postoperative care: Early range of motion of the elbow is essential unless fixation is tenuous.

Complications

Posttraumatic arthritis: This results from articular injury at time of trauma as well as a failure to restore articular congruity.

Failure of fixation: Postoperative collapse of fixation is related to the degree of comminution, the stability of fixation, and protection of the construct during the postoperative course.

Loss of motion (extension): This is increased with prolonged periods of immobilization. Range-of-motion exercises should be instituted as soon as the patient is able to tolerate therapy, unless fixation is tenuous.

Heterotopic bone

Neurologic injury (up to 15%): The ulnar nerve is most commonly injured during surgical exposure.

Nonunion of osteotomy: 5% to 15%

Infection

Condylar Fractures

These are rare in adults and are much more common in the pediatric age group.

Less than 5% of all distal humerus fractures are condylar; lateral fractures are more common than medial.

Medial condyle fractures: These include the trochlea and medial epicondyle and are less common than medial epicondylar fractures.

Lateral condyle fractures: These include the capitellum and lateral epicondyle.

Mechanism of Injury

Abduction or adduction of the forearm with elbow extension

Classification

Milch

Two types are designated for medial and lateral condylar fractures; the key is the lateral trochlear ridge (Fig. 17.4):

Type I: Lateral trochlear ridge left intact

Type II: Lateral trochlear ridge part of the condylar fragment (medial or lateral)

These are less stable.

They may allow for radioulnar translocation if capsuloligamentous disruption occurs on the contralateral side.

Jupiter

This is low or high, based on proximal extension of the fracture line to the supracondylar region:

Orthopaedic Trauma Association Classification

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

Low: equivalent to Milch type I fracture

High: equivalent to Milch type II fracture

Treatment

Anatomic restoration of articular congruity is essential to maintain the normal elbow arc of motion and to minimize the risk of posttraumatic arthritis.

Nonoperative

This is indicated for nondisplaced or minimally displaced fractures or for patients with displaced fractures who are not considered candidates for operative treatment.

This consists of posterior splinting with the elbow flexed to 90 degrees and the forearm in supination or pronation for lateral or medial condylar fractures, respectively.

Operative

This is indicated for open or displaced fractures.

This consists of screw fixation with or without collateral ligament repair if necessary, with attention to restoration of the rotational axes.

Prognosis depends on:

• The degree of comminution

• The accuracy of reduction

• The stability of internal fixation

Range-of-motion exercises should be instituted as soon as the patient can tolerate therapy.

Complications

Lateral condyle fractures: Improper reduction or failure of fixation may result in cubitus valgus and tardy ulnar nerve palsy requiring nerve transposition.

Medial condyle fractures: Residual incongruity is more problematic owing to involvement of the trochlear groove. These may result in:

• Posttraumatic arthritis, especially with fractures involving the trochlear groove

• Ulnar nerve symptoms with excess callus formation or malunion

• Cubitus varus with inadequate reduction or failure of fixation

   

  Capite lum Fractures

These represent <1% of all elbow fractures.

They occur in the coronal plane, parallel to the anterior humerus.

Little or no soft tissue attachments result in a free articular fragment that may displace.

Anterior displacement of the articular fragment into the coronoid or radial fossae may result in a block to flexion.

Mechanism of Injury

This results from a fall onto an outstretched hand with the elbow in varying degrees of flexion; force is transmitted through the radial head to the capitellum. Fracture occurs secondary to shear.

These are occasionally associated with radial head fractures.

Classification

Orthopaedic Trauma Association Classification

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

Additional Classification (Fig. 17.5)

Type I: Hahn-Steinthal fragment: large osseous component of capitellum, sometimes with trochlear involvement

Type II: Kocher-Lorenz fragment: articular cartilage with minimal subchondral bone attached: “uncapping of the condyle”

Type III: Markedly comminuted (Morrey)

Type IV: Extension into the trochlea (McKee)

Treatment

Nonoperative

Primarily used for nondisplaced fractures

Consists of immobilization in a posterior splint for 3 weeks followed by range of elbow motion

Operative

Goal is anatomic restoration

Open reduction and internal fixation

• This technique is indicated for displaced type I fractures.

• Via a posterolateral or posterior approach, screws may be placed from a posterior to anterior direction; alternatively, headless screws may be placed from anterior to posterior.

• Fixation should be stable enough to allow early range of elbow motion.

Excision

• This is rarely indicated for severely comminuted type I fractures and most type II fractures. Care must be taken in the elderly as these are often type IV fractures, which if excised will lead to elbow instability.

• This may be the recommended treatment in chronic missed fractures with limited range of elbow motion.

  Complications

Osteonecrosis: This is relatively uncommon.

Posttraumatic arthritis: The risk is increased with failure to restore articular congruity and excision of the articular fragment.

Cubitus valgus: This may result after excision of articular fragment or with an associated lateral condylar or radial head fracture. It is associated with tardy ulnar nerve palsy.

Loss of motion (flexion): This is associated with retained chondral or osseous fragments that may become entrapped in the coronoid or radial fossae.

Trochlea Fractures (Laugier Fracture)

Extremely rare

Associated with elbow dislocation

Mechanism of Injury

Tangential shearing force resulting from elbow dislocation

Treatment

Nondisplaced fractures may be managed with posterior splinting for 3 weeks followed by range-of-motion exercises.

Displaced fractures should receive open reduction and internal fixation with Kirschner wire or screw fixation.

Fragments not amenable to internal fixation should be excised.

Complications

Posttraumatic arthritis may result from retained osseous fragments within the elbow joint or incongruity of the articular surface.

Restricted range of motion may result from malunion of the trochlear fragment.

Lateral Epicondylar Fractures

Extremely rare

Mechanism of Injury

Direct trauma is the mechanism in adults.

Prepubescent patients may experience avulsion fractures.

Treatment

Symptomatic immobilization is followed by early range of elbow motion.

Complications

Nonunion may result in continued symptoms of pain exacerbated by wrist or elbow motion.

Medial Epicondylar Fractures

More common than lateral epicondylar fractures owing to the relative prominence of the epicondyle on the medial side of the elbow

Mechanism of Injury

In children and adolescents, the medial epicondyle may be avulsed during a posterior elbow dislocation.

In adults, it is most commonly the result of direct trauma, although it can occur as an isolated fracture or associated with elbow dislocation.

Treatment

Nondisplaced or minimally displaced fractures may be managed by short-term immobilization for 10 to 14 days in a posterior splint with the forearm pronated and the wrist and elbow flexed.

Operative indications

• Fragments within the joint space

• Relative indications include displaced fragments in the presence of ulnar nerve symptoms, elbow instability to valgus stress, wrist flexor weakness, and symptomatic nonunion of the displaced fragment.

• Open reduction and internal fixation versus excision: Excision is indicated for fragments not amenable to internal fixation or are incarcerated within the joint space and are irreducible.

  Complications

Posttraumatic arthritis: This may result from osseous fragments retained within the joint space.

Weakness of the flexor mass: This may result from nonunion of the fragment or malunion with severe distal displacement.

Fractures of the Supracondylar Process

The supracondylar process is a congenital osseous or cartilaginous projection that arises from the anteromedial surface of the distal humerus.

The ligament of Struthers is a fibrous arch connecting the supracondylar process with the medial epicondyle, from which fibers of the pronator teres or the coracobrachialis may arise.

Through this, arch traverse the median nerve and the brachial artery.

Fractures are rare, with a reported incidence between 0.6% and 2.7%, but they may result in pain and median nerve or brachial artery compression.

Mechanism of Injury

Direct trauma to the anterior aspect of the distal humerus

Treatment

Most of these fractures are amenable to nonoperative treatment with symptomatic immobilization in a posterior elbow splint in relative flexion until pain free, followed by range-of-motion and strengthening exercises.

Median nerve or brachial artery compression may require surgical exploration and release.

Complications

Myositis ossificans: The risk is increased with surgical exploration.

Recurrent spur formation: This may result in recurrent symptoms of neurovascular compression, necessitating surgical exploration and release, with excision of the periosteum and attached muscle fibers to prevent recurrence.