Distal Humerus Fractures

The difficulty in treating complex distal humerus fractures lies in the unique and specific anatomy of the distal humerus, which allows it to articulate freely with the radius and ulna. The elbow is a trochoginglymoid joint; it has the capacity to flex and extend within the sagittal plane and also to rotate around a single axis. In fact, the elbow joint consists of three different articulations, as follows:

• Radiocapitellar joint
• Olecranon-trochlear joint
• Proximal radioulnar joint

Motion within the sagittal plane occurs at the ulnohumeral articulation within the semilunar notch.

The distal humerus resembles a triangle, with the medial and lateral columns making up the sides and the trochlea forming the base (270° arc). The diaphyseal cortical cylindrical shape of the distal humerus splays out into a narrow isthmus to form the medial and lateral triangular columns. These columns are separated by a very thin layer of bone that posteriorly makes up the olecranon fossa and anteriorly composes the coronoid fossa.

The lateral column ends distally in the capitellum. The articular surface of the capitellum represents the anterior surface of the inferior lateral column, with a 180° arc. The medial column is entirely nonarticular, with the ulnar nerve lying directly inferior in the cubital tunnel.

Reconstruction of the premorbid anatomy of the trochlea is crucial to restoration of motion and stability. The lateral column lies in approximately 20° of valgus relative to the humeral shaft. The medial column is aligned at a 40° angle to the shaft and ends in the trochlea. The capitellum is angulated 30-40° anteriorly, and the trochlea is angulated 25° anteriorly.

The ulnohumeral articulation is slightly asymmetric. The trochlea is larger in diameter medially than laterally, and this explains the normal carrying angle of the arm as it is extended. The trochlea ends more distally than the capitellum in the coronal plane, leading to a valgus position of the elbow when the arm is fully extended. When the elbow is flexed, the capitellum is projected further anteriorly, resulting in a varus posture. It is important to remember that the distal humeral articular surface is positioned at the normal carrying angle of 11-17° of valgus angulation.

Most distal humerus intra-articular fractures split through the trochlear waist, causing comminution and often leading to narrowing of the trochlea after internal fixation. In addition, the condyles are rotated 3-8° internally and positioned in approximately 6° of valgus. Often, the olecranon blocks adequate visualization of the trochlea and olecranon fossa, limiting evaluation of fracture reduction.

In the pediatric population, during the first 6 months, the distal ossification border is distinct and symmetric. The ossification center of the lateral condyle appears in infants around age 1 year. The medial epicondyle appears in children aged 5 years at the medial metaphyseal region. The trochlea ossifies in children aged 9 years. The lateral epicondyle begins to form and fuse with the lateral condyle in children aged 10 years. Before the end of growth, the capitellum, lateral epicondyle, and trochlea fuse to form the epiphysis. However, the medial epicondyle is usually the last to fuse, in adolescents aged 14-17 years.

The blood supply around the elbow is primarily fed by anastomotic vessels from the brachial artery. Most vessels supplying the lateral condyle enter posteriorly and course into the ossific nucleus. They feed into the lateral portion of the trochlea.

Most distal humerus fractures can be classified into one of the following two etiologic groups:

• Those resulting from a high-energy mechanism, such as a motor vehicle accident (MVA)
• Those resulting from a low-energy injury, such as a fall while walking

The incidence of fractures of the elbow joint is small compared with that of fractures of other bones. Elbow joint fractures have been estimated to make up 4.3% of all fractures. Typically occurring after high-energy injury, these fractures can lead to significant functional impairment. Distal humerus fractures most commonly involve both medial and lateral columns. Single condylar fractures make up approximately 5% of distal humerus fractures. Epicondylar and coronal shear fractures of the articular surface are less commonly observed.

A retrospective study by Mitchelson et al found that individuals undergoing surgery for distal humerus fractures were more likely to be obese, younger than 40 years, female, and recipients of Medicare with relatively few comorbidities, who resided in a rural setting and sought care at urban/teaching hospitals within the southern United States; in addition, they were more likely to have shorter hospital stays, to be discharged home, and to have better survival.[5]

In the pediatric population, 80% of all elbow fractures occur in the supracondylar region. The injury typically occurs in young boys aged 5-10 years.

Loss of terminal extension is frequently observed after distal humerus fracture. Chronic exertional pain can be observed in as many as 25% of patients who have suffered such injury.

Henley and other authors reported good-to-excellent results in 92% of treated patients at 1.5-year follow-up.[6] Other studies reported similar numbers, with a range of 60-90% and good-to-excellent results.

Wang et al reported that most poor results tend to occur with complex group C3 fractures and are related to associated injuries and complications.[7] In their study of 20 patients, four complications occurred: one nonunion, one malunion, one deep infection, and one brachial artery laceration.

McKee et al studied functional outcome following surgical treatment for displaced intra-articular distal humerus fractures.[8] After 37 months of follow-up, they found a mean flexion contracture of 25° and an arc of motion of 108°. Significant decreases in mean muscle strength were found in both elbow flexion and extension (75% of normal).

Outcome studies have reported healing rates of 80-100% postoperatively. Jupiter reported postoperative arc of motion improved to 100°, with 83% good or excellent functional results.[9, 10]

Regarding surgical exposure for distal humerus fractures, a nonunion rate of up to 40% has been reported from chevron osteotomy outcomes, though some authors contend that poor technique is often the source of the complications. Contributory factors include lack of interdigitation of the osteotomy site, malposition of the intramedullary fixation screw, infection, and broken implants.

Bashyal et al reviewed the incidence of infection and other complications in 622 children with supracondylar distal humerus fractures who underwent closed reduction and percutaneous pin fixation.[11] The most common complication was pin migration necessitating return to the operating room for pin removal in 11 patients. Six patients (1%) developed infections. One had a malunion; four underwent repeat reduction and pinning; and three developed compartment syndromes. The authors concluded that closed reduction with percutaneous pinning has a low complication rate, with a very low rate of infection, and they noted that preoperative antibiotics had little effect on the infection rate.

Mighell et al retrospectively reviewed 18 patients who underwent ORIF with headless compression screws for large coronal shear fractures of the distal humerus without posterior comminution.[12] Seventeen of the patients had good-to-excellent results according to the Broberg-Morrey scale. Three patients developed avascular necrosis (AVN), and five developed arthrosis. No reoperations were necessary.

In a study aimed at identifying predictors of postoperative adverse events in adults who undergo surgical treatment of distal humerus fracture, Movassaghi et al found that open fractures are more likely to be associated with delayed union.; that ulnar nerve injury, open fracture, and polytrauma were all predictive of reoperation; and that older patients were less likely to undergo subsequent surgery but more likely to have heterotopic ossification.[13]

A thorough patient history must be taken in the initial evaluation of these patients. Medical history, surgical history (especially pertaining to the injured extremity), medication use, nonmedication drug use, occupation, and smoking history should be ascertained. In an elderly patient, the reason for the fall must be investigated.

The mechanism of injury also can help to identify other associated bony or ligamentous injuries. Questions regarding the speed of the motor vehicle accident (MVA) or the height from which a fall occurred and the position of the arm at impact should be asked.

Understanding the premorbid condition of the patient's injured extremity also is important, as is ascertaining any preexisting limitations, such as degenerative or traumatic arthritis, instability, stiffness, or neurologic abnormalities (acute or chronic), that may affect treatment.

With high-energy injuries, associated injuries to the head, chest, abdomen, spine, or pelvis must be excluded. Standard screening radiographs, including radiographs of the pelvis, spine, and chest, are obtained (see Workup).

Physical examination of the patient should include examination of the injured extremity and a thorough primary and secondary survey to determine if any associated injuries are present.

A complete examination of the neurovascular status of the extremity should be conducted. An accurate assessment should be made of the sensory and motor contributions of the median (including the anterior interosseous), ulnar, and radial (including the posterior interosseous) nerves, as well as the medial and lateral antebrachial cutaneous nerves. The brachial artery and median nerves lie anterior to the elbow joint and are at risk for disruption.

The distal pulses should be palpated and the capillary refills should be assessed, with comparisons made to the contralateral upper extremity. If questions regarding vascular status arise, duplex Doppler studies or angiography should be performed (see Workup).

Inspection and palpation also should be part of the examination. Open wounds communicating with the joint are common with high-energy injuries. These wounds should initially be treated with antibiotics and tetanus prophylaxis. A povidone-iodine dressing should be placed over the wound to prevent further wound colonization and exposure.

The skin should be examined for bruising, ecchymosis, or lacerations, with these findings taken into consideration, especially if operative intervention is to be initiated. Bruising, ecchymosis, or lacerations may represent significant ligamentous damage and resultant instability.

A well-padded, well-molded splint with the elbow in slight flexion and neutral rotation provides stability and pain relief until definitive treatment is possible. The splint should be applied with a nonconstrictive dressing. Signs of compartment syndrome of the forearm or upper arm also should be clinically investigated.

Preoperative laboratory studies should be patient-specific. They should be performed to medically clear the patient for an operative procedure if one is justified.

Studies should include coagulation studies and hemoglobin level. If the patient's medical condition is in question, then a medical team consultation may be appropriate. Whereas blood loss can be minimized with the intraoperative use of a tourniquet, typing and screening can be performed if the patient is unable to tolerate blood loss.

The fracture personality, including the bone quality, fracture pattern, level of comminution, articular involvement, displacement, and associated injuries, must be understood completely before treatment is attempted.[14]  Multiplane radiographs, including anteroposterior (AP) and lateral views, are appropriate. (See the images below.)

AP radiographs should be obtained with the elbow flexed approximately 40° and with the radiographic beam directed perpendicular to the distal humeral surface. This allows disengagement of the olecranon from its fossa and permits a better view of the distal humerus. In the pediatric population, the Baumann angle—defined as the angle between the lateral condylar physeal line and the axis of the humerus—is often measured by using AP radiographs. It must be compared with the angle on the contralateral side.

In addition, displacement of the anterior, posterior, or supinator fat pad can suggest a fracture. The posterior fat pad is the most sensitive for pathology. Skaggs et al demonstrated a 76% incidence of occult elbow fracture with a positive posterior fat pad sign.[15]  A medial epicondylar fracture should be suspected if a fragment is visible within the joint and the epicondyle is not visible.

Oblique radiographs can aid in assessing multiplane involvement of the fracture lines and comminution.

In many instances, traction views allow better visualization of the fracture lines and fragments. Mobile fluoroscopy can be helpful as well, especially in cases associated with seemingly minor fractures and instability.

Other radiographic views of the elbow can be obtained to exclude associated injuries. A radial head–capitellar view is a semilateral view of the elbow with the beam aimed 45° toward the ipsilateral shoulder joint. With the thumb of the hand pointed upward, the radial head can be magnified without any overlap of the proximal ulna. The coronoid view can be obtained to define the coronoid process. The radiographic beam is directed at the lateral elbow and pointed 45° away from the ipsilateral shoulder.

Computed tomography (CT) of the distal humerus can be performed to further analyze the fracture pattern. Thin-cut coronal and axial cuts at 1 mm intervals should be obtained. Three-dimensional reconstructions can be obtained but rarely contribute much to the overall assessment of the fracture. The integrity of the central column, as well as comminution and preexisting arthritic changes within the joint surfaces, should be observed. Often, CT scans reveal details that cannot be viewed on simple radiographs.

A study suggested that additional CT could improve intraobserver reliability but did not improve interobserver agreement, indicating that interpretation is a reflection of training, knowledge, and experience.[14]  Another study found that although adding CT to radiography did not improve interobserver reliability, it did change fracture classification and treatment planning.[16]

If questions regarding vascular status arise, duplex Doppler ultrasonography (US) or angiography can be performed. US has also been shown to be helpful in differentiating stable from unstable pediatric lateral condylar fractures. Vocke-Hell et al showed US to be effective in determining which nonossified fractures involved the joint surface and required operative intervention.[17]

No perfect classification system has been developed for distal humerus fractures that allows accurate direction for treatment considerations and prognostic outcome. The many classifications that have been proposed often overlap.

Mehne and Jupiter separated fractures on the basis of column involvement and whether the fractures are intra-articular, intracapsular, or extracapsular.[9, 18]  Their classification system incorporates features of many previously described fracture types.

For single-column involvement, the Milch classification is often used. It classifies fracture patterns as having medial or lateral condylar involvement and further characterizes them as either low (type I) or high (type II), depending on how proximally the fracture started before traveling obliquely across the trochlea. These fractures usually occur from an abduction or adduction force.

Kuhn et al described a divergent bicolumn fracture pattern that can occur with an axial force from the olecranon in patients with fenestrated olecranon/coronoid fossae.[19]

Capitellar and trochlear fractures are seen infrequently, occur in the coronal plane, and can be classified into one of the following subtypes:

• Type I - These are isolated capitellar fractures involving a large portion of cancellous bone; they are known as Hahn-Steinthal fractures
• Type II - These are fractures involving the anterior cartilage, with a thin-sheared layer of subchondral bone; they are known as Kocher-Lorenz fractures
• Type III fractures - These are comminuted osteochondral fractures
• Type IV fractures - Classified by McKee et al, these involve the capitellum and one half of the trochlea; they often result in the double-arc sign observed on lateral radiographs

For bicolumn variants, the classification system introduced by Mehne and Matta takes into consideration the height of the fracture through each column, as follows:

• Y and T fractures begin in the center of the trochlea, secondary to trochlear impaction into the olecranon-trochlear ridge, causing propagation of the fracture vertically and across each column; if a fracture involves both columns at a distal level, it may enter the olecranon and coronoid fossae and produce comminuted articular fragments too small to reconstruct
• H-type fractures may produce a free-floating trochlear fragment, with the medial column fractured in two places; this can increase the risk of avascular necrosis of the articular fragment; the system does not identify comminution or fragment displacement

Many have continued to use the simple classification proposed by Riseborough and Radin,[20] which differentiates fractures on the basis of displacement and rotation. The use of this classification system is limited because it does not account for the large variety of fracture patterns. Riseborough and Radin's classification is as follows:

• Type I - Fractures involving minimally displaced articular fragments
• Type II - Fractures involving displaced fragments that are not rotated
• Type III - Fractures involving displaced and rotated fragments
• Type IV - Fractures involving comminuted fracture fragments

The Arbeitsgemeinschaft für Osteosynthesefragen (AO)-Orthopaedic Trauma Association (OTA) classification is the most commonly used system for clinical research and treatment.[21] The OTA and the International Society for Fracture Repair expanded the AO-ASIF classification to provide a more detailed system for reproducibility. It contains 28 different fractures of the distal humerus and separates the patterns into groups and subgroups according to the specific fracture propagation and involvement.

The AO-OTA group classification is as follows[21] :

• Group A - Extra-articular fractures
• Group B - Partial articular fractures
• Group C - Complete articular fractures

The subgroup classification is as follows[21] : 

• Subgroup A1 - Avulsion fracture
• Subgroup A2 - Simple fracture
• Subgroup A3 - Wedge or multifragmentary fracture
• Subgroup B1 - Lateral sagittal fracture
• Subgroup B2 - Medial sagittal fracture
• Subgroup B3 - Frontal/coronal plane fracture
• Subgroup C1 - Simple articular, simple metaphyseal fracture
• Subgroup C2 - Simple articular, wedge or multifragmentary metaphyseal fracture
• Subgroup C3 - Multifragmentary articular fracture, wedge or multifragmentary metaphyseal fracture

The classification system most commonly used for pediatric supracondylar humerus fractures is the Gartland classification, which is based on the degree of displacement. Skaggs et al found a high interobserver reliability with this classification system and an overall κ value of 0.74.[22] The Gartland classification system is as follows:

• Type I - Nondisplaced fractures
• Type II - Minimally displaced fractures with an intact posterior cortex
• Type III - Completely displaced fractures with complete cortical disruption

Pediatric supracondylar humerus fractures can also be classified as extension-type and flexion-type fractures, depending on the angulation of the distal fragment.

Lateral condylar physeal fractures can be differentiated on the basis of either the anatomic location of the fracture or the amount of displacement. The Milch classification is as follows:

• Type I (Salter-Harris type IV) - Describes the fracture extending lateral to the trochlea through the capitulotrochlear groove
• Type II (Salter-Harris type II) - Describes the fracture line penetrating to the trochlea, producing elbow instability

Medial condylar physeal fractures also are classified according to the Milch classification, as follows:

• Type I - Salter-Harris type II fracture
• Type II - Salter-Harris type IV fracture

Fracture separation of the distal humeral epiphysis also has been described. (In some cases, separation of the epiphysis with an attached portion of the metaphysis may occur.) DeLee et al classified this type of fracture into the following three groups[23] :

• Group A - These fractures involve patients aged 1 year or younger with Salter-Harris type I physeal injuries
• Group B - These fractures involve children aged 1-3 years in whom ossification of the lateral condyle epiphysis is evident
• Group C - These fractures occur in children aged 3-7 years and produce a metaphyseal flag with the distal fragment

The decision to offer operative intervention for distal humerus fractures is based on many factors, including fracture type, intra-articular involvement, fragment displacement, bone quality, joint stability, and soft-tissue quality and coverage. In addition, individual factors, such as patient age, overall health condition, functional extremity demands, and patient compliance, are all considered. Preoperatively, patients must understand outcome expectations and the importance of rehabilitation.

Conditions in which operative intervention is supported include the following:

• Intra-articular fragment displacement
• Physeal displacement
• Supracondylar comminution and displacement
• Open fractures
• Floating elbow patterns
• Neurovascular injury
• Compartment syndrome
• Multiple traumatic injuries

The first goal of operative intervention is to restore articular congruity and elbow stability. Another goal is to decrease the possibility of posttraumatic arthritis and elbow stiffness.

Contraindications for operative treatment of distal humerus fractures are patient-specific. Patient factors that should be considered include the following:

• Age
• Overall health condition
• Functional demands and expectations
• Overlying soft-tissue quality and bone quality

Finally, the surgeon must be able to make an honest evaluation of his or her ability to successfully perform open reduction and internal fixation (ORIF) of the fracture pattern.

Although distal humerus fractures remain a challenging reconstructive problem for orthopedic surgeons, future technology may hold many solutions. With the advent of newer, stronger biocompatible materials, diverse hardware options allow improved reduction and fixation of distal humerus fractures. Lower-profile plates and smaller screws allow the surgeon to maintain the original articular congruity needed to prevent posttraumatic arthrosis, which allows for faster and progressive postoperative rehabilitation.

In addition, for the unreconstructable elbow, primary total elbow arthroplasty (TEA) is gaining acceptance.[24, 25] Significant improvements in its design and surgical technique have produced reliable pain relief and functional restoration. Although rigid patient selection criteria should be adhered to with this surgical option, it appears that TEA may be of particular help to elderly patients with severe bone loss and comminution; however, the risk of complications is not insignificant.[2, 26] Elbow hemiarthroplasty (EHA) has also been described as a possible alternative to TEA in older patients.[3, 27, 28]

Nonoperative treatment depends on the fracture type. Casting and immobilization can be used for nondisplaced fractures, particularly with medial, lateral, and supracondylar process fractures (extra-articular and extracapsular).

Medial epicondylar fractures can be immobilized for 7 days, with the elbow flexed at 90º, the forearm pronated, and the wrist flexed at 30º to relax the common flexor-pronator muscle group. If more than 3 mm of displacement is present or the fragment is trapped in the medial joint, attempts at closed reduction often fail, and ORIF is necessary.

Lateral epicondylar fractures can be immobilized with the elbow in 90º of flexion, the forearm in supination, and the wrist extended slightly to relax the extensor muscles.

Stable, nondisplaced extra-articular distal humerus fractures can be treated with a short period of splinting or casting in a long arm cast (usually for approximately 2 weeks), followed by use of a hinged functional brace with early elbow motion. Often, gentle closed reduction consisting of axial traction in neutral rotation with correction of the deformity can be attempted for maximal anatomic reduction. An olecranon Kirschner wire (K-wire) traction apparatus with later brace conversion has been described, with use depending on the patient's medical status (ability to tolerate an operative procedure) and soft-tissue condition.

Although the outcome after nonoperative treatment may include reduction imperfections with prominent callus formation and slight varus angulation, good elbow function is generally obtained if early range-of-motion (ROM) exercises can be instituted. Articular involvement or fractures with significant comminution, displacement, or both are poorly tolerated and require ORIF.

In the pediatric population, only nondisplaced supracondylar humerus fractures are treated in a closed manner. The patient's arm can initially be placed in a posterior splint, with transition to a long arm cast when soft-tissue swelling has diminished. For extension-type fractures, the elbow is placed at 90º of flexion, with the forearm in neutral rotation. Type II and III extension-type fractures often require stabilization with percutaneous pins in order to maintain reduction.

If closed treatment for a stable type II fracture is desired, then reduction is maintained by keeping the elbow in at least 120º of flexion and full pronation. However, if any concern exists about circulatory impairment or swelling, then percutaneous pinning is recommended. Stable, nondisplaced flexion-type supracondylar humerus fractures should be immobilized in a long arm cast with the elbow in extension.

Lateral condylar fractures often require treatment with operative stabilization because of their unstable fracture pattern. Minimally displaced, stable type I fractures can be treated with immobilization and close monitoring to prevent late displacement. Pirker et al studied 51 pediatric lateral condylar fractures that had minimal displacement and found that 9.8% of these later became displaced.[29]

Fracture separations of the distal humeral epiphysis must be recognized early, and closed reduction should be attempted. The reduction maneuver involves flexion and pronation of the forearm to prevent medial translocation of the distal fragment.

Studies have supported the notion that distal humerus fractures in adults are optimally treated with open anatomic reduction and stable fixation to allow early anatomic restoration and upper-extremity ROM. Although operative intervention is not without complications, the risk can be reduced by paying detailed attention to anatomic reduction, soft-tissue handling and preservation, stable fixation, and early mobilization.

For articular fractures and unstable nonarticular fractures, operative treatment with direct visualization of the joint surface and anatomic reduction and stabilization can prevent accelerated arthritis associated with articular incongruity.

If the injury involves significant contamination from external sources or bone devitalization, then osteosynthesis is delayed following serial irrigations and debridements. Temporary fixation with a bridging external fixator, however, can be performed. Olecranon skin traction is an option for persons who have fractures with excessive soft-tissue swelling and in patients with multiple traumatic injuries who require rapid, temporary skeletal stabilization.

Other reconstruction options include autograft or allograft support and fascial arthroplasty. In relatively inactive elderly patients with poor bone quality, TEA is indicated for comminuted distal humerus fractures when ORIF is not feasible.[30, 31]  EHA may yield comparable results in many of these patients.[3] Elbow arthrodesis is a severely limiting alternative and is very rarely performed.

Distal humerus fracture repair is illustrated in the images below.

Preparation for surgery

Preoperative planning is essential before surgical treatment of a distal humerus fracture. Proper imaging studies and physical examination findings help determine the appropriate surgical approach and techniques necessary for a functional outcome.

Contralateral distal humerus radiographs may be required to create a template of the restored anatomy of the injured extremity. Soft-tissue involvement may dictate the location of the incision. Tracing paper can be used to mark the fracture fragments and lines, as well as the anatomic reduction.

The steps of the procedure, including patient positioning, surgical approach, provisional fixation, and definitive treatment, should be discussed and documented.

The patient should be positioned to allow adequate exposure and visualization of the entire involved area. Previous authors have supported a wide range of positions, from supine to prone to the lateral decubitus position.

For single-column or shear fractures, the supine position is helpful in order to use the lateral approach to the elbow. An arm board or hand table can be placed at the side of the operating table for support of the medial portion of the arm. The authors prefer to use the lateral decubitus position with a beanbag for support and a padded, sterile arm holder under the proximal humerus.

The hip-holder attachment to the Jackson table also can be used as an arm holder. This allows adequate access to the posterior portion of the elbow joint and also permits the arm to be freely rotated proximally for more accurate positioning.

The hand and forearm are draped with a sterile stockinette. The shoulder is placed at 90° of abduction, and the elbow is flexed over the arm holder at 90°. The lateral position also allows access to either the anterior or posterior iliac crest in case a bone graft is needed. The prone position is rarely used.

Other considerations for positioning should include associated injuries, simultaneous procedures that will be performed during the same anesthetic administration, and the patient's overall systemic demands (such as those resulting from closed head injuries).

A tourniquet should be applied as far proximally on the brachium as possible. With supracondylar or high column fractures, a sterile tourniquet is needed. The entire arm should be prepared and draped.

Surgical approaches

Several different surgical approaches, with variations, have been described. For isolated single column or epicondylar injuries, a lateral or straight medial approach is recommended. ORIF using a combined medial-lateral approach has been employed for intra-articular fractures of the distal humerus.[32]

The lateral (Kaplan) approach involves an incision proximal to the lateral epicondyle that is extended distally across the radiohumeral interval. Dissection is carried down between the extensor carpi radialis brevis (ECRB)–extensor digitorum communis (EDC) interval or between the EDC–extensor carpi radialis longus (ECRL) interval until the supinator is visualized. Detachment of the heads of the supinator reveals the anular ligament and the lateral column of the distal humerus. If the incision is to be extended distally, the posterior interosseous nerve must be protected.

The posterolateral (Kocher) approach may be safer for exposure of the lateral column because it uses the anconeus–extensor carpi ulnaris (ECU) interval, better protecting the posterior interosseous nerve. An incision is started just proximal to the lateral epicondyle and ends obliquely across the proximal ulna. The arm is kept pronated during the dissection to keep the posterior interosseous nerve away from the dissection field.

Blunt dissection through the ECU fascia and through the anconeus-ECU interval leads to the elbow joint capsule. Exposure distal to the anular ligament leads to the posterior interosseous nerve. The lateral collateral ligament (LCL) is visualized by retracting the ECU and EDC anteriorly.

The capsular incision should be made anterior to the radiohumeral ligamentous complex to avoid injury to the posterior fibers of the LCL complex and to prevent resulting instability. If truly necessary for exposure, the LCL may be detached from the lateral epicondyle and then reattached with nonabsorbable suture or suture anchors.

The medial approach involves the interval between the brachialis and the medial collateral ligament (MCL). Proximal extension is made through the brachialis-triceps interval. A similar posteromedial approach has been described as well for fracture fixation and medial placement of a single plate. This allows dissection of the radial nerve to be avoided but may not be appropriate in settings with preoperative radial nerve injuries.[33]

The posterior (Campbell) incision is most often used for nonarticular supracondylar fractures or intra-articular fractures. The incision can be curved gently, either medially or laterally, at the olecranon to avoid impingement directly over the apex. The ulnar nerve should be isolated carefully and at least 6 cm mobilized both proximally and distally to the cubital tunnel to allow the nerve to lie within the subcutaneous tissues anteromedially to the cubital tunnel (transposition).[10, 7, 34]  Careful attention should be paid to the release of the medial intermuscular septum and distal dissection of the nerve within the flexor carpi ulnaris (FCU).

A triceps-splitting approach is most commonly used for exposure of the distal humerus. This technique involves deep dissection down the middle of the arm over the olecranon, along with fascial and periosteal flap elevation along the sides of the bone. Medial triceps insertion avulsion has been reported and must be carefully avoided.

The anconeus fibers and the FCU fibers are elevated off the bone laterally and medially for improved distal exposure. Proximally, the radial nerve crosses within the deep muscle fiber origin of the medial triceps head 13-15 cm above the joint line. The triceps insertion should be preserved as much as possible and should be reattached through drill holes if released. This approach has been reported to lead to devascularization-induced triceps rupture and may increase adhesion formation.

The triceps-sparing approach described by Bryan and Morrey is particularly advocated for use in intra-articular fractures of the distal end of the humerus when conversion to an elbow arthroplasty or to a TEA is necessary as the primary treatment.[35]

The ulnar nerve is isolated and is transposed anteriorly (though it has been suggested that anterior transposition may not always be necessary[36] ). The triceps is dissected subperiosteally and is elevated from medial to lateral for exposure of the distal humerus. It is kept in continuity with the forearm fascia and periosteum, and the triceps insertion is directly from the ulna. Variants of this technique have described a lateral-to-medial reflection of the triceps mechanism. The ulnar collateral ligament (UCL) may be released from the distal humerus to improve exposure. Reattachment is necessary after fracture repair, but reattachment is not necessary following TEA.

Some authors prefer a nonarticular olecranon osteotomy, with proximal retraction of the triceps with its insertion for visualization of the distal humerus. This involves an osteotomy performed distal to the articular olecranon. The osteotomy can be directed transversely (modified MacAusland technique) or obliquely (Mueller technique).

Because of the inherent risk of fracture nonunion, many authors prefer a triceps-sparing approach or an intra-articular olecranon osteotomy. For improved exposure for intra-articular fractures, the posterior approach is often combined with an intra-articular osteotomy. Direct visualization allows accurate reduction of the joint surfaces. Both transverse and chevron osteotomies have been described. The authors prefer a chevron osteotomy with direct fixation using a tension band wire technique and K-wires.

The osteotomy can also be fixed with an intramedullary 6.5-mm cancellous screw, which can be predrilled and tapped before the osteotomy for easier placement. The curvature of the proximal ulna may make it difficult to achieve accurate placement of the screw down the intramedullary canal.

The olecranon is sharply dissected along the medial and lateral portions to afford a better view of the semilunar notch. Typically, an oscillating thin-blade saw is used, with the osteotomy cuts converging obliquely and distally, just distal to the midportion of the semilunar notch. The amount of articular cartilage is least here.

The osteotomy is completed with an osteotome. Use of the osteotome allows improved engagement of the fragments after reduction. The remaining capsular attachments and the soft tissue bordering the triceps are cut to allow proximal retraction of the olecranon tip with the triceps insertion. The olecranon tip is elevated off the posterior aspect of the humerus. The ulnar nerve is isolated and transposed with this approach.

After distal humerus fracture fixation, the proximal ulna can be reattached by using standard Arbeitsgemeinschaft für Osteosynthesefragen (AO)-Association for the Study of Internal Fixation (ASIF) tension-band wire technique and either two parallel 0.0625-mm K-wires or a 6.5-mm partially threaded cancellous screw, as described previously. The tension-band wire should be placed underneath the triceps, against the bone periosteal surface, and secured with either the K-wires or the cancellous screw. The transverse distal wire hole should be placed well distal to the osteotomy site.

Reduction and stable fixation

A methodical approach should be taken to reduction and fixation of the fracture fragments. All of the fracture fragments should be identified initially. Hematoma should be removed, and the fracture planes should be identified and restored.

If one column remains intact, the reduction can be simplified by assembling the fragments against the intact column. For bicolumnar involvement, some physicians prefer first to stabilize one column and then to reduce the second column to the first column. A more common approach is to start with the articular surface and to anatomically reduce the joint surface. The metaphyseal fragments are then separately reduced and fixed. This effectively converts the fracture into a two-part fracture.

Others prefer a "best-fit" method of anatomic restoration. By starting with the portion that can be best anatomically aligned and is least comminuted, errors in reduction can be minimized.

Provisional reduction can be accomplished with K-wires or bone-holding forceps. Most surgeons begin with reconstitution of the trochlea and work proximally. The trochlea can be stabilized back to the shaft and the least-fractured column. With articular comminution, it is important to restore the normal articular surface depth and width. Central comminution or missing articular fragments should be replaced with bone graft obtained from the iliac crest. Fixation should be obtained with interfragmentary 4.0 cancellous lag screws crossing both the medial and the lateral column to maintain reduction.

For more extensive comminution, a fully threaded, nonlagged 4.0 cancellous screw should be placed across the trochlea to prevent narrowing across the gap. Retrograde drilling through one of the fracture fragments is recommended to maintain a central position of the screw. The screw can then be placed from the capitellar fragment across the fracture site and into the trochlear fragment.

Low columnar fragments may also be fixed with small cannulated differential pitch screws buried beneath the articular surface or small threaded K-wires buried under the articular surface. Once the articular fragments have been reduced, the stabilized distal fragment is reduced to the shaft. Precontoured plates can be placed onto the shaft over K-wires that stabilize the construct. A metaphyseally placed screw can hold the plate initially for stability.

Various implants are available today for the diverse fracture patterns observed in the distal humerus. Some plates are contoured specifically for the anatomy of the distal humerus. Several companies have developed anatomically based precontoured condylar plate systems that can assist with fracture reduction.[37]

Screws ranging from cannulated to noncannulated and ranging in size from 2.7 mm (minifragment screws) to 3.5 mm and 4.5 mm (small- and large-fragment screws) may be needed. Most small-fragment implant sets have 3.5-mm and partially threaded 4.0-mm screws up to 50 mm in length. If longer screws are needed, 3.5-mm screws up to 110 mm in length are available.

Various minimally invasive percutaneously inserted bridge plates also have been described and have been used to avoid extensive dissection and potential nerve injury. Some have shown good results in their utilization, even with prior radial nerve palsy, anticipating eventual nerve recovery.[38]

Plate placement is the keystone of fracture reduction. Once articular reconstruction is completed, the lateral column is fixed with a molded 3.5-mm dynamic compression plate, or a reconstruction plate is placed posterolaterally.

The posterior aspect of the lateral condyle has a bare surface immediately proximal to the articular surface, making it safe for plate placement. However, the posterior capitellar articular surface limits distal placement of the plate. Screws can be directed anterosuperiorly, above the capitellum, or directed anteriorly, gaining fixation distally only by the near cortex (in order to avoid joint penetration) and gaining bicortical fixation proximally.

The medial column is stabilized with a one-third tubular plate or a 3.5-mm reconstruction plate placed in an orthogonal fashion with respect to the lateral plate. The medial column of the distal humerus is nonarticular, and a plate can be contoured into a semicircle along its distal end to cradle the medial epicondyle. The most distal screw can be oriented superiorly at a 90° angle to the more proximal screws, enhancing stability, or obliquely, to engage the lateral column.[39]

Orthogonal plate placement has been demonstrated to provide the greatest stability for avoiding a variety of failure loads.[40]  However, Schemitsch et al demonstrated that with cortical contact, plates placed medially and laterally were as rigid as those placed orthogonally.[41] A meta-analysis by Li et al found that parallel and perpendicular double plating yielded similar results for acute type C fractures but that the former had fewer complications.[42] Care must be taken to prevent olecranon hardware impingement in elbow extension. Jupiter described placing a third plate laterally along the lateral column for added fixation.[9, 10]

Basic principles for internal fixation of these fractures include the following:

• All distal screws from one column should pass through a plate
• All distal screws should pass into a major fragment on the opposite column
• All screws should be as long as possible to engage the opposite cortex
• All screws should engage as many fragments as possible
• Screws approaching the articular surfaces and fossae should be avoided

O'Driscoll described the use of "contact with compression" in order to obtain increased stability across the fracture site. Fixation of the articular fragments onto the proximal supporting columns creates the weakest link. By obtaining compression across the fracture site, the limb is shortened slightly. This leads to overlap of fragments, which improves overall stability and the ability to institute early ROM to prevent elbow stiffness.

Fixation of distal humerus fractures often is determined by the fracture pattern. With divergent single-column injury patterns, two to five lag screws placed percutaneously from side to side may be employed for adequate fixation. For coronal shear fractures, small cannulated screws placed from anterior to posterior through the articular surface anteriorly may be used. Partially threaded 4.0-mm cancellous bone screws also can be placed from posterior to anterior through the fracture line, gaining unicortical fixation.

After fixation is achieved, it is important to carefully assess the entire ROM of the elbow in order to evaluate stability. If olecranon impingement limits extension, hardware may have to be modified, or the tip of the olecranon may be excised. Other options for improving stability include bone autograft or allograft, bicortical interpositional grafting for bone loss (often for malunions), and polymethylmethacrylate (PMMA) with screw augmentation. If such options fail, then a hinged external fixator may be considered as a salvage procedure. TEA is an option for comminuted distal humerus fractures in the elderly.

A drain is placed, and the soft tissue and skin should be closed in layers. The elbow joint is immobilized in a well-padded, well-molded splint that is in full extension to limit swelling.

For pediatric supracondylar humerus fractures, extension-type fractures are initially manipulated with the patient completely relaxed in order to achieve stable anatomic reduction. Traction is established, and then the limb is hyperextended with varus or valgus correction and hyperflexed to stabilize the fracture. Finally, forearm pronation is recommended to stabilize the distal fragment in the coronal plane.

Similarly, with flexion-type fractures, the elbow is reduced in extension, and the previously mentioned reduction technique is performed. Careful attention should be paid to applying pressure posteriorly onto the distal fragment through the forearm when flexing the elbow so as to maintain reduction of the distal fragment.

Type III flexion-type injuries are notorious for necessitating open reduction. Several authors have described various closed methods of reduction for this type of fracture. If open reduction is needed, an anteromedial approach is often used because of the anterolaterally displaced fragment. The proximal fragment is usually impaled within the triceps mechanism.

Controversy has persisted concerning the benefits of crossed percutaneous pinning versus those of lateral pinning for stable fixation of supracondylar humerus fractures. Lee et al, among others, provided biomechanical evidence that crossed pinning provides a stronger construct.[43]  Skaggs et al showed in retrospective studies that the configuration of the pins does not affect final fracture reduction of type II or III supracondylar humerus fractures.[22]

The lateral pins are placed first with the elbow in hyperflexion and pronation. The pin or pins should be placed in the center of the lateral condyle and directed at 30° to the humeral axis. The medial pin or pins should be started at the medial epicondyle and directed anterolaterally. Before pin insertion, the ulnar nerve should be palpated, or soft tissue should be dissected and the epicondyle visualized. Studies have shown a high incidence of ulnar nerve subluxation with flexion of the elbow during the reduction maneuver.

Attention should be paid to preventing pins from crossing at the fracture site. The pins are cut outside of the skin and bent back. The arm should be placed in a long arm splint postoperatively, with transition to a long arm cast (worn for at least 3 weeks).

Open reduction with pinning is the treatment of choice for displaced pediatric lateral and medial condylar fractures. Rotational displacement is very difficult to evaluate with closed reduction maneuvers. A direct lateral approach to the elbow is recommended for lateral fragments through the brachioradialis-triceps interval. Posterolateral dissection should be avoided in order to preserve the vascularity from the posteriorly located vessels.

A posteromedial incision is used for medial fragments. The fracture site is carefully debrided, and two smooth K-wires are inserted through the condyle or metaphyseal fragment and into the medial humeral metaphysis. The pins can be kept under or external to the skin but require removal after 3 weeks. The arm is protected in a long arm splint, with transition to a long arm cast (worn for 3 weeks).

Fracture separation of the epiphysis can be treated with open reduction and pinning if recognized early. Separations are often missed, and if they are discovered after 5-7 days, they should be splinted and allowed to heal with remodeling.

There has been some discussion regarding the timing of operative treatment for closed pediatric supracondylar humerus fractures. Typically, if the patient is neurovascularly stable, the arm is splinted, and the patient is taken to the operating room as soon as possible. Mehlman et al provided strong evidence that no difference exists in perioperative complication rates for displaced supracondylar humerus fractures treated before or after an 8-hour period.[44]

The entire extremity should be elevated above the level of the heart to reduce swelling. The drain can be removed after 24-48 hours, when drainage diminishes. Once the swelling abates, the elbow can be placed in a supportive brace or sling, and gentle active ROM exercises can be initiated. Passive ROM exercises are delayed 6 weeks to allow for early fracture healing.

In patients who have undergone a triceps-sparing approach, active extension is prevented for the first 6 weeks. Instead, elbow extension is achieved through gravity. Passive ROM, including dynamic flexion and extension splints as needed, is instituted 6 weeks after surgery. Strengthening is begun 10 weeks after surgery.

Most pediatric elbow fractures can initially be treated in a long arm posterior splint for comfort after surgery, with transition to a long arm cast. The pins are removed after 3 weeks, and the cast is removed after 3-4 weeks. Protected ROM can be initiated at this time.

The most commonly observed complication after operative treatment is loss of elbow motion. Physical therapy, including active and passive ROM, as well as static progressive splinting, is useful treatment. Nonoperative treatment is usually successful only for an extrinsic elbow contracture that has been present for less than 6 months.

If nonoperative treatment fails, operative release is recommended. Most often, an open approach is used. Mansat and Morrey described a limited lateral approach to both the anterior and posterior capsule called the column procedure.[45] This involves elevating muscles from the lateral supracondylar osseous ridge. Mansat and Morrey had an 11% complication rate; hematoma formation and ulnar nerve paresthesia were the most common complications. Other authors have described arthroscopic approaches to capsular release.

Anatomic reduction with stable fixation of fracture fragments, careful handling of the ulnar nerve, and adequate fixation of an olecranon osteotomy can improve the results of surgical treatment. Failure of fixation is most often the result of poor preoperative planning and poor operative technique, though bone quality may limit stable fixation. Careful rehabilitation progression can optimize the opposing forces of motion maintenance and fracture healing.

Nonunion rates for surgically treated distal humerus fractures are in the range of 2-7%. Infection, bone osteoporosis, age, open fractures, multiple injuries, and inadequate fixation are among the factors leading to nonunion. Symptoms include persistent pain, weakness, and instability, though most patients maintain up to an 80º arc of motion. If surgical treatment is chosen, options include revision ORIF, allograft reconstruction, and resection or distraction arthroplasty.[46, 47]

TEA may be considered in elderly, less active patients.[48]  A study by Medvedev et al found early complication rates to be low and comparable to those of ORIF.[49]  Barco et al, in a study evaluating long-term (>10 y) outcomes of TEA in 44 patients with distal humerus fractures, found that whereas selective use of this procedure for infirm, less active older patients and patients with inflammatory arthritis had acceptable longevity in surviving patients, this longevity came at the cost of several major complications.[50]

With pediatric elbow fractures, nonunions of the lateral condyle are the most common. Compression fixation and bone grafting are recommended as treatment.

Heterotopic ossification can occur in as many as 50% of cases after acute treatment of distal humerus fractures. It typically occurs in the posterolateral aspect of the elbow, from the lateral humeral condyle to the posterolateral olecranon. Hastings and Graham described a functional classification system for elbow ectopic ossification that assists in clinical evaluation, treatment, and operative planning, as follows[51] :

• Class I - These fractures are associated with no functional limitations
• Class IIA - These fractures are associated with functional limitation of flexion and extension; they result in anterior or posterior ossification or ossification involving both sides of the elbow joint
• Class IIB - These fractures involve functional limitation of supination and pronation and also may involve ossification of the interosseous membrane or distal radioulnar joint
• Class III - These fractures are associated with ankylosis that eliminates elbow ROM

Some studies have found a lower incidence of heterotopic ossification formation when ORIF is performed within 24-48 hours of injury. Heterotopic ossification incidence is increased with associated injuries, such as burns, head injuries, high-energy injuries, and open injuries. In these patients, prophylactic treatment should be considered. Forced passive manipulation also may increase the development of heterotopic bone formation.

Preventive measures include the use of nonsteroidal anti-inflammatory drugs (NSAIDs), low-dose radiation therapy, and continuous passive ROM exercises. Most studies have looked at heterotopic ossification treatment around the hip. Regardless, the treatment of heterotopic ossification continues to be controversial.

NSAIDs have been used with success against heterotopic ossification. Indomethacin is the most commonly used drug for heterotopic ossification prevention and has been shown to decrease the incidence and severity of this complication. The recommended dosage is 75 mg orally 2 times per day for 3 weeks. Sucralfate, at a dosage of 1 g orally four times per day, has been recommended to prevent gastrointestinal disturbances in patients taking indomethacin.

Low-dose radiation therapy with single doses of 6-7 Gy to the elbow has been successful at preventing further progression. The timing of the irradiation (preoperative vs postoperative) does not seem to affect operative outcomes. Some authors have recommended irradiation within 72 hours of elbow trauma. The concerns of neoplasm development after radiation treatment are evident.

Operative excision of heterotopic ossification is recommended 12 months after the injury, though studies have shown good results with treatment 3-6 months after the injury. Declining levels of serum alkaline phosphatase (ALP) and the radiographic confirmation of mature heterotopic bone can be used to help predict timing for heterotopic bone excision. However, studies have shown no difference in serum ALP levels in matched populations with or without ectopic ossification. As a result, they are not routinely indicated.

Combined medial and lateral approaches are recommended for removal of heterotopic bone. Cut bone surfaces should be cauterized and covered with bone wax, and extensive capsular release should be performed.

Instability after distal humerus fracture fixation is rare. It is most often observed with untreated type II single-column injuries or radial head or coronoid fractures. With comminuted intra-articular fractures, it may not be possible to reconstruct associated ligamentous injuries. Hall et al described the use of a hinged external fixator to treat associated posterolateral instability of a severely comminuted distal humerus fracture after having been unable to stabilize the joint after ORIF.[52]  Although the distal humeral condyles may be fractured, the medial and lateral ligamentous attachments typically remain preserved, lending stability to the elbow after operative stabilization.

Patient complaints related to ulnar nerve dysfunction are among the most frequent findings after surgical treatment of distal humerus fractures, affecting some 7-15% of patients. Postoperative ulnar nerve dysesthesia symptoms with intact motor examination findings are common and can be closely monitored. Revision operative procedures have revealed extensive fibrosis and fracture healing that causes the ulnar nerve to adhere to the medial epicondylar area.

Mobilization and anterior transposition at the time of index surgery decrease the incidence of this complication. Furthermore, a 2011 study suggested that performing intramedullary antegrade nailing, rather than crossed K-wire fixation, as the index surgery for supracondylar humeral fractures reduces the risk of ulnar nerve injury.[53]  A retrospective study by Al-Gburi et al, however, suggested that the risk of the ulnar nerve being affected after surgical treatment of acute distal humerus fracture is low when the ulnar nerve is released in situ without anterior transposition, independently of whether the treatment provided consists of ORIF, TEA, or EHA.[36]

With more proximally involved fractures, the radial nerve should be identified upon exposure. It can be damaged by retraction, plate impingement, or tissue dissection during the operation. If a change in baseline motor nerve function on postoperative examination occurs, reexploration is recommended. Brachial artery injuries have been described and are more common with extension-type elbow injuries. The brachial artery can be damaged by the sharp ends of the proximal fragment penetrating its wall.

Dormans et al, along with Cramer et al, studied the high incidence of anterior interosseous nerve injuries associated with closed pediatric supracondylar fractures.[54, 55] Return of function occurred within 10 months without surgical intervention. Overall, the authors found a 9.5% incidence of nerve injury. Radial nerve injuries have been found to be more common with posteromedial displaced fractures, whereas median nerve injuries have been associated with posterolateral angulated fractures.

Avascular necrosis (AVN) is extremely rare after distal humerus fractures. Isolated studies have reported an increased risk of AVN of the free-floating fragment after H-type intra-articular distal humerus fractures.

AVN of the trochlea is associated with more distally based pediatric humerus fractures. Injury to the physeal vasculature of the medial trochlea can lead to AVN, resulting in a fishtail deformity. Malreduction of a lateral condylar fracture can lead to development of a bony bar within the physis and to development of a fishtail deformity.

Angular deformities, such as cubitus varus and cubitus valgus, are rare complications after pediatric supracondylar humerus fractures. Often, anatomic reduction prevents development of these deformities. Cubitus valgus is very rare and often occurs with posterolateral fracture patterns. It often leads to more functional loss (typically of extension) than does cubitus varus. Lateral condylar fractures can lead to cubitus varus angulation. A combination of nonanatomic reduction and physeal growth stimulation leads to this deformity. Most of the time, the degree of deformity is of little consequence.

Oh et al described seven of 12 young children in whom fracture separation of the distal humeral epiphysis led to cubitus varus deformity, with development of AVN of the medial humeral condyle occurring in six of the seven patients.[56]

Inpatient care is recommended for 2-3 days, with the wound carefully examined 48-72 hours after surgery. In addition, excessive swelling and signs of compartment syndrome should be monitored. The wound should be examined again by 14 days after surgery, and the sutures should be removed. Fracture healing should be assessed with serial radiographs to examine callus formation, alignment, and hardware integrity. Bony union is anticipated by 3 months after surgery. With pediatric fractures, bony union is expected sooner, and ROM can be initiated earlier.