Distal Humeral Fractures
Articular fractures of the distal humerus represent only about 2% of all fractures, but they always present a challenge to the treating orthopaedic surgeon because of the complex anatomy of the distal humerus and elbow. There are two distinct subgroups of patients in whom these injuries occur1,2: younger patients sustaining high-energy fractures (Fig. 16.1); and elderly patients, often with osteoporosis, sustaining low-energy fractures in ground-level falls (Fig. 16.2).
High-energy injuries differ from low-energy injuries in the proportion of open fractures and the incidence of injuries to more than one organ system. With the high-energy injury there is typically extensive comminution of the articular surface and metaphyseal region, and there can be bone loss in open injuries (Fig. 16.1). High-energy injuries also entail associated soft tissue injury, which needs to be considered in the planning and timing of treatment of these patients.
Low-energy injuries in the elderly may have significant comminution that is due to the poor bone quality rather than the energy of the injury. These injuries represent a different challenge to the surgeon in terms of nonoperative and operative treatment; standard techniques of internal fixation that are successful in the young may fail in the elderly due to poor bone quality. The elderly patient frequently has medical comorbidities. The skin may be quite thin and thus needs meticulous handling.
Most distal humerus fractures are treated operatively, especially those with articular injuries. A review of the literature documents that one can realistically expect 85% good or excellent results, ranging from 50 to 100% depending on the population studied and the instrument that was used to assess outcomes.2–12 Some studies have specifically evaluated the outcome of these injuries in the elderly.13,14 Although one can expect good results in terms of fracture union with stable fixation, the functional outcomes indicate that disabling injuries with residual impairment of elbow function are common among older patients.13,14 In selected elderly patients with severely comminuted distal humerus fractures, total elbow arthroplasty may provide better results in terms of functional scores, range of motion, and decreased reoperation rates.15–18
The desired functional outcome after treatment of an intra-articular fracture of the distal humerus is a painless elbow with satisfactory mobility. Achieving this requires careful surgical planning and execution in order to anatomically reconstruct the articular surface and restore the overall anatomy while providing stable fixation that allows early mobilization. In practice, realizing these goals is difficult in patients with osteoporotic bone, significant comminution, or soft tissue problems. There are many reported complications of treatment, including contractures, infection, nonunion, failure of fixation, symptomatic hardware (more so with the olecranon osteotomy), ulnar nerve dys-function, and heterotopic ossification.
Classification
A number of classification systems have been proposed for articular distal humeral fractures. Early classification schemes regard fractures of the intercondylar region of the distal humerus as being T- or Y-type.19,20 However, there has been an increased understanding of the complex anatomy of these fractures manifest by recognition that the distal humerus is best described by columns rather than condyles, thus allowing the fractures to be more accurately described.
Riseborough and Radin19 proposed four types of fractures including a nondisplaced fracture (type I), displaced T or Y fractures that separate the condyles from each other and from the shaft (type II), fractures with rotational displacement of the condyles (type III), and displaced fractures with rotation and intra-articular comminution (type IV). This is perhaps one of the simplest fracture classifications for the distal humerus, but its simplicity limits its usefulness in describing the types of distal humerus fractures.
Mehne and Jupiter20 divided bicolumnar fractures of the distal humerus into seven main types: high T fracture, low T fracture, Y fracture, H fracture, medial lambda fracture, lateral lambda fracture, and multiplanar fracture. This classification system is useful in the description of low columnar fractures. Ring and Jupiter21 note that this classification does not work well for fractures in multiple planes, and especially in the coronal plane.
The AO/Orthopaedic Trauma Association (OTA) comprehensive fracture classification organizes fractures of the distal humerus into three main groups, each with nine subtypes.22 Just as it does for other periarticular fractures, the AO/OTA classification includes extra-articular (type A), partial articular (type B), and complete articular fractures (type C), and then further categorizes them based on the pattern and extent of the extra-articular and intra-articular comminution. This system provides more choices in the description of fractures but does not provide much useful information for guiding treatment, and it is difficult to use for clinical decision making except in its most rudimentary form (A vs B vs C) (Fig. 16.3).23
Coronal Shear Fractures
Coronal plane fractures, typically caused by a shearing mechanism, represent an unusual but important subtype of distal humeral fractures that are important to recognize, as they are difficult to repair (Fig. 16.4). These fractures may be isolated or can occur in association with other fractures of the distal humerus. A classification system for these specific injuries was originally described by Bryan and Morrey24 and modified by McKee et al.25 Type I, also known as a Hahn-Steinthal fracture, represents a coronal fracture of the capitellum. Type II, also known as a Kocher-Lorenz fracture, is an osteochondral lesion of the capitellum. Type III is a comminuted fracture, and a type IV is a capitellar fracture with extension into the trochlea.
Tips and Tricks
With all fractures of the distal humerus, rather than relying on a specific fracture classification, it is more valuable for the surgeon to recognize the multiplanar fracture lines and their relationship to the articular surface, to determine whether there is coronal shear fracture, and to understand the extent of involvement of the medial and lateral columns and the olecranon fossa (Fig. 16.5).
Nonoperative Treatment
Nonoperative treatment of intra-articular distal humerus fractures is rarely appropriate for certain fracture subtypes and population groups. However, a given patient may have associated trauma or medical comorbidities that represent contraindications to surgery. Stable extra-articular distal humerus fractures (AO-OTA type A) can be treated nonoperatively as long as reasonable alignment can be maintained. Such a fracture may be reduced with gentle axial traction and then placed in a posterior splint in neutral rotation. Once the soft tissue problems are resolved, the arm may be placed in a cast. To begin early range of motion, a hinged elbow brace or a cast-brace should be applied after 2 or 3 weeks. In a multiple-trauma patient, it may be difficult to obtain or maintain acceptable reduction of an otherwise simple AO/OTA type A distal humeral fracture, and in such a patient it is reasonable to treat an otherwise stable distal humerus fracture operatively. Fixation of such fractures may facilitate the care and mobilization of multiple-trauma patients.
A very rare indication for nonoperative treatment of a distal humeral fracture is a severely comminuted fracture in a patient with significant osteoporosis that precludes reconstruction. Such treatment has been described as the “bag of bones” technique, and consists of using a sling or collar and cuff immobilization using one of two methods: (1) immobilization between 100 and 125 degrees of flexion, increasing the amount of extension over the course of 3 weeks; or (2) active motion initiated after 2 weeks of immobilization with the elbow at 90 degrees.21 These patients may obtain an adequately mobile pain-free elbow with limited morbidity considering their systemic and local conditions. However, if fracture comminution or severe osteoporosis is the reason for selecting nonoperative treatment, total elbow arthroplasty is a more contemporary option and should be considered an alternative for such patients who are otherwise fit for surgery.15–18
When nonoperative management is chosen, the patient should be closely followed with serial (initially weekly) radiographic assessment to ensure that the reduction is maintained. Multiple adjustments to the splint may be needed, and repeat closed reduction may be necessary should follow-up radiographs demonstrate loss of the initial reduction.
Indications for Surgical Treatment
Physical Examination
The evaluation of a patient with a distal humerus fracture should include assessment of the fracture and surrounding soft tissues including neurovascular structures. The posterior soft tissues especially should be carefully evaluated for the presence of an open wound. An open posterior wound indicates involvement of the extensor mechanism of the elbow and should be kept in mind during surgical planning.
There are several neurovascular structures that cross the elbow, and consideration of the direction of fracture displacement will assist in the identification of neurovascular structures at risk for injury. The brachial artery crosses the elbow anteriorly, and may be injured when there is significant anterior displacement. The vascular status is assessed by evaluation of the distal pulses and comparison to the opposite arm. When asymmetry of the distal pulses or compromised capillary refill are noted, further objective vascular evaluation is warranted. This includes Doppler-derived occlusion pressures taken at the wrist or forearm and compared with those of the contralateral extremity. If asymmetric pressures are confirmed, additional evaluation with angiography should be considered.
There are three major peripheral nerves that cross the elbow joint: the median, radial, and ulnar nerves. The motor and sensory function of these nerves should be evaluated as part of the physical examination. The presence of ulnar nerve dysfunction prior to surgery may affect the decision regarding intraoperative management of the ulnar nerve. Complete evaluation of the injury includes examination of the shoulder, forearm, and wrist, in addition to a survey of the entire patient. In a patient with a high-energy injury, additional systemic injuries may impact the surgical decision making and affect the type of treatment and timing of surgery.
Radiographic Evaluation
Following a distal humerus fracture, orthogonal radiographs should be obtained in the anteroposterior (AP) and medial-lateral projections. For the AP view of the elbow, the arm and forearm are positioned horizontally, resting on a radiolucent support, with the elbow joint fully extended and the fingers slightly flexed. The beam is directed perpendicular to the elbow joint. This view demonstrates the distal humeral shaft, the elbow joint, and proximal portions of the radius and ulna in the coronal plane (Fig. 16.6).
For the lateral projection of the elbow, the patient′s arm is abducted 90 degrees at the shoulder so that the forearm rests on the imaging plate on its medial side, with the elbow flexed 90 degrees and the thumb pointing upward. The beam is then directed vertically toward the radial head. The film in this projection demonstrates details regarding the distal humerus, the olecranon, and radial head in the sagittal plane (Fig. 16.7).
Good-quality radiographs are necessary for surgical planning. However, because of the pain of the injury or the displacement of the fracture, it is often difficult to obtain true AP and lateral radiographs as described. In this case, a traction radiograph may be of assistance in planning the surgical procedure. For this view, gentle longitudinal traction is applied to the patient′s arm in an extended position. In this way, a better AP view may be obtained. Similarly, it may difficult to flex the injured elbow and it may be necessary to obtain the lateral radiograph in an extended position.
Radiographs alone provide adequate information regarding the bony injury for the initial evaluation, and more advanced imaging is rarely necessary. Routine computed tomography (CT) scanning is not necessary, but it may assist with surgical planning in fractures with significant articular comminution and in those known or suspected coronal-plane fractures of the distal humerus.
Tips and Tricks
Traction X-rays are valuable in preoperative planning.
With open fractures or fractures requiring temporizing stabilization with an external fixator, always keep in mind the definitive surgery and draw the planned incision.
Surviving the Night
The surgical reconstruction of a closed intra-articular distal humerus fracture is not an ideal procedure to perform in the middle of the night. However, open distal humerus fractures may occur, and irrigation/debridement of the open wound should be done as soon as it is practical, to minimize risk of infection. The more contaminated and the larger the wound, the more quickly it should be debrided surgically. When open wounds are present, they are usually posterior. During debridement of the wound, any surgical extension of the traumatic wound should take into account the eventual exposure that is necessary for insertion of internal fixation.
When definitive surgical management is going to be delayed for a short period of time (e.g., 1 to 2 days), the arm can be splinted. Occasionally, external fixation is considered for provisional management of open fractures, closed fractures with severe associated soft tissue injury, or in multiply injured patients who cannot tolerate definitive surgery acutely. Again, the definitive treatment plan needs to be considered when planning the external fixation pin placement so that the pins are not in the way of later incisions or hardware.
Closed fractures may not always be benign, and sometimes they present with features that demand immediate attention. A fracture that has significant displacement with sharp fragments may “tent” the skin. This pressure on the skin from within may ultimately lead to skin breakdown. If surgery is to be delayed, this displacement should be corrected by closed reduction in order to minimize tension on the skin from the fracture.
Surgical Treatment
Video 16.1 Total Elbow Arthroplasty
General Concepts
Ultimately, the goals of fixation of distal humeral fractures are as follows: provide a stable and mobile elbow joint, obtain union between the metaphyseal and diaphyseal bone, enable soft tissue healing, minimize the risk of infection, and enable the patient to rapidly regain functional use of the upper extremity. In 1952, Cassebaum26 described five principles of operative treatment of distal humerus intra-articular fractures: (1) reestablish the relationship of the distal humeral condyles to each other and the relationship of the condyles to the ulna; (2) keep the olecranon fossa open; (3) preserve and reestablish the forward tilt of the articular surface of the condyles; (4) perform fixation of the condyles to the humeral shaft; and (5) obtain secure fixation. These principles remain valid today and provide the foundation for contemporary surgical management of these complex fractures.
Considerations in Planning Surgical Treatment
Distal humerus fractures involving the articular surface may occur from a high- or low-energy mechanism. It is important to remember that distal humeral fractures may be associated with a soft tissue injury that may affect surgical timing and planning. In addition, the soft tissues may have significant bruising and abrasions. Although incisions through areas of ecchymosis may not have significant implications in terms of rate of infection, incisions through superficial abrasions or lacerations may result in complications. Thus, the skin should be examined closely, and surgery should be performed only when the soft tissue incisions can be made without increasing the patient′s risk of infection.
Principles of Surgical Approaches
Preoperative Planning
Surgical fixation of distal humerus fractures should be performed as soon as possible after injury, ideally within the first week. Early fixation minimizes the risk of skin breakdown from the splint, protects the soft tissues from the pressure of displaced bone fragments, and may decrease stiffness following an injury that is often complicated by decreased range of motion. If the patient has multiple injuries, special considerations may be required. For example, repair of the fracture may need to be delayed while more serious injuries are stabilized. If surgery must be delayed, the patient′s arm may be splinted with a well-padded posterior splint with medial and lateral plaster reinforcements. If the patient is intubated, the skin should be frequently evaluated prior to surgery.
Surgery should be planned based on careful radiographic assessment of the fracture type. Appropriate X-rays include an AP radiograph (preferably performed with traction) and a lateral radiograph (Figs. 16.6 and 16.7). When open reduction and internal fixation of distal humerus fractures is needed, plate fixation is the only practical option. Therefore, there are two primary considerations in preoperative planning: (1) choosing the type, number, and length of plates to be used; and (2) deciding whether an olecranon osteotomy is necessary. With complex intra-articular distal humerus fractures, an olecranon osteotomy should be considered for access to the distal humeral articular surface. Whether or not an olecranon osteotomy is necessary will depend on the location of any intra-articular extension, the presence of an anterior coronal-plane fracture, and the degree of comminution. Simple fractures lines that extend into the joint near the lateral edge of the trochlea may be managed with triceps-sparing approaches, whereas more complex patterns are likely to require the increased visualization provided by osteotomy. Preoperative planning with the use of templates should be done to ensure that the appropriate equipment is available. In addition, there should be an assortment of multiple screws of different sizes, Kirschner wires (K-wires), and reduction clamps.
For most distal humeral fractures, double plating of the distal humerus is recommended (Fig. 16.8). Any controversy regarding double plating lies in the choice of plate orientation: parallel plates supporting the two columns (medial and lateral) (Fig. 16.8b); or perpendicular plate fixation, with medial plate fixation on the medial column and posterior plate fixation on the lateral column (Fig. 16.8a). Although older biomechanical evaluations of various plate positions determined that 90-degree constructs were the strongest, more recent biomechanical studies comparing anatomically precontoured plates suggest that parallel plating may be superior to perpendicular plating.27,28 In a prospective, randomized study comparing the two constructs, Shin et al29 found no significant differences between the treatment groups, although the more traditional perpendicular plating group had more nonunions. Sanchez-Sotelo et al4 reported the results of their parallel-plate technique and found no cases of hardware failure or fracture displacement. It is important for the surgeon to carefully evaluate the fracture pattern and determine which plate configuration provides a stable construct for a given fracture pattern.
The use of precontoured locked plates has significantly increased in popularity. Evidence indicates that locking plates have improved fixation in osteoporotic bone in general.30 However, when applied to a simulated distal humerus fracture, plate configuration (parallel versus perpendicular) was more important than plate type (reconstruction plate versus locking compression plate).27,31 There are no high-quality clinical series available to address whether locking fixation itself is of benefit; existing studies are small uncontrolled case series.32,33 The use of locked plates or precontoured plates should be balanced with the needs of the patient, the fracture type, and the cost/benefit ratio of these plates.
An extra-articular fracture (AO/OTA type A) may be treated with plating of just the medial or lateral column. Standard plates are available from different manufacturers that are specifically designed for application to the distal humerus.
Patient Positioning
The positioning of the patient needs to be considered for each case, as supine, lateral, and prone positions are all possible. With the patient in the lateral position, the elbow may be flexed over a tray or bolster. For the lateral decubitus position, a beanbag is preferred with an axillary roll and all bony prominences well padded (Fig. 16.9).
Prone positioning works very well for exposure of the distal humerus, but it may be a little more difficult to flex the patient′s elbow unless the arm is hung over the edge of a table. When the lateral decubitus or prone positions are contraindicated, the patient may be positioned supine. In this position, the shoulder has to be flexed and adducted, and the arm pulled across the patient′s chest by an assistant. Most often, the choice of position simply depends on surgeon preferences.
Regardless of the position chosen, while the patient is being positioned it is recommended that the arm be suspended in order to prevent telescoping of the fragments and further damage to the soft tissues. Draping should enable exposure of the entire arm up to the axillary region. One should not forget the potential need for tourniquet use, and consider applying a tourniquet or have a sterile tourniquet available. After the prepping and draping are completed, alcohol should be used to remove the Beta-dine® prior to placement if a sterile tourniquet is used. Prophylactic antibiotics should be provided.
Intraoperative Imaging
With the exposures used to perform fixation of distal humerus fractures, there is normally adequate visualization of the fracture site and joint surface. However, intraoperative images should be obtained in the AP and lateral planes to ensure adequate reduction of the joint surface, overall alignment of the limb, and positioning of the implants. Depending on the position of the patient during surgery, fluoroscopy is useful to evaluate temporary fixation of the joint surface and plate placement. Placement of the C-arm may vary depending on the position of the patient, and images should be taken before the final prepping and draping of the patient to ensure that adequate imaging is possible.
Surgical Approaches
All approaches for fixation of distal humerus fractures start with a posterior skin incision, with several variations of dissection through or sparing the triceps muscle (Fig. 16.10).
Posterior: Triceps Sparing or Splitting
A midline posterior incision is made over the distal humerus, around the tip of the olecranon, and continued distally. The incision should not be directly over the tip of the olecranon, because this may contribute to wound issues and discomfort for the patient postoperatively. The incision should be carried out sharply through the skin to the level of the triceps aponeurosis. There are two possible deep approaches once the skin incision is made. The triceps may be split longitudinally to expose the distal humerus (Fig. 16.11). Alternatively, a triceps-sparing approach can be used that utilizes mobile windows made on either side of the triceps while maintaining the triceps insertion (Fig. 16.12). This is done whenever possible in order to minimize soft tissue trauma. When sparing the triceps, the distal humerus is first approached laterally. As one dissects distally along the lateral aspect of the triceps, the posterior radial collateral arterial system is visualized and protected. Sharp dissection is used to elevate the triceps off the distal fragment at the level of the olecranon fossa. Proximally, along the lateral aspect of the arm, the radial nerve is identified as it passes through the lateral intermuscular septum. The radial nerve may then be followed proximally over the posterior aspect of the humerus. At this point, if further proximal exposure of the humeral shaft is needed, the tourniquet may need to be deflated and removed. The triceps may then continue to be mobilized medially with attention being paid to the radial nerve and its vena comitantes and the sensory nerve branches. On the medial side of the triceps, the dissection along the humerus is continued sharply and the ulnar nerve should be identified and followed down to the medial epicondyle. Once the ulnar and radial nerves have been identified, the olecranon osteotomy may be completed if desired (see following section). For some fractures with minimal or no articular involvement (AO/OTA type A or B fractures), mobilization of the triceps as described above may provide adequate exposure without further work. If visualization of the joint surface is needed, there are two options: formal olecranon osteotomy, or reflection of the triceps aponeurosis off of the proximal ulna in continuity with the forearm fascia.
For the triceps-splitting approach, the same posterior incision is used. The ulnar nerve is identified. The triceps is split in line with the incision to the bone (Fig. 16.13). The triceps may be split to the olecranon if needed. A tendinous cuff should be preserved medially and laterally to enable reattachment at the end of the procedure. In this manner, a triceps splitting approach is advantageous in eliminating the need for an olecranon osteotomy if adequate visualization is obtained.
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