The surgical treatment of fractures of the distal humerus remains one of the most difficult challenges faced by the orthopedic surgeon.
Recent trends for early mobilization of elbow fractures and/or dislocations postinjury or postoperatively have improved outcomes.
The close anatomic proximity between the bones of the elbow and neurovascular structures frequently leads to associated neurovascular injury. Therefore, a comprehensive examination to determine if iatrogenic injury has occurred is essential.
The goals of surgical management are anatomic reconstruction of the fracture fragments and stable internal fixation. This will allow an early controlled range of motion (ROM) program to be established, minimizing the possibility of posttraumatic contracture and the development of heterotopic ossification.
The majority of elbow joint dislocations can be treated with closed reduction and immobilization. An early motion program should be quickly established to minimize postinjury stiffness.
The elbow joint is a complex structure composed of three distinct articulations—the ulnohumeral, radiocapitellar, and proximal radioulnar joints. The main function of the elbow joint is to position the forearm and hand in space. For this purpose, the elbow joint allows motion in two distinct planes: flexion-extension and pronosupination. In addition to positioning the forearm and hand in space, the elbow joint also serves an important load-bearing function in the upper extremity.
Injuries to the elbow joint are often difficult to treat, not only because of the anatomic complexity of the joint but also because of the propensity of the articulation for the development of stiffness and contracture. Because the joint is critical to upper extremity motion, a painful, stiff elbow can lead to significant functional disability. Recent trends in early mobilization and the establishment of physical and occupational therapy protocols in the postinjury-postoperative period have led to improved functional outcomes.
Fractures of the Distal Humerus
The distal end of the humerus can be divided into separate medial and lateral columns. The columns are triangular in shape and are bordered at the edges by thick, bony supracondylar ridges. Distally, the columns form two distinct surfaces called condyles, which possess articular and nonarticular segments. The articular segment of the medial condyle is the trochlea, named for its spool-like shape. It is a cylindrical structure that articulates with the proximal ulna to form the ulnohumeral joint, a hingelike articulation primarily responsible for flexion and extension of the elbow. The articular segment of the lateral condyle is the capitellum, a hemispherical structure that articulates with the radial head. The radiocapitellar articulation, together with the proximal and distal radioulnar joints, is primarily responsible for pronation and supination of the forearm. The medial and lateral epicondyles of the humerus represent the nonarticulating segments of the condyles, and serve as the point of origin of the collateral ligaments and the forearm flexor and extensor muscle groups, respectively. The coronoid and olecranon fossae are surface depressions located between the medial and lateral columns proximal to the condyles. The fossae accommodate the coronoid process anteriorly when the joint is flexed and the olecranon process of the ulna posteriorly when the elbow is extended. The medial and lateral collateral ligament complexes originate from the medial and lateral epicondyles of the distal humerus ( Fig. 78-1 ).
Population-based studies have shown a prevalence of 5.7 per 100,000 of these injuries, which occur in a bimodal distribution. The first peak occurs in male patients aged 12 to 19, while a second peak is seen in women over 80 years of age. Fractures of the distal humerus are often the result of high-energy injuries such as motor vehicle accidents. In these patients, associated intracranial, intra-abdominal, and other associated musculoskeletal injuries must be carefully ruled out. Specifically, ipsilateral proximal humerus and distal radius fractures should be considered. Occasionally, distal humerus fractures may occur as a result of falls from a standing height onto an outstretched arm. This mechanism of injury is most commonly seen in elderly patients with osteoporotic bone and can also be associated with ipsilateral upper extremity bony injuries, especially fractures of the distal radius and ulna.
On physical examination, the elbow is often swollen with obvious deformity. A careful neurovascular examination should be performed to rule out and document associated injuries. The close anatomic proximity between the distal humerus, the brachial artery, and neural structures (median, ulnar, radial nerves) often leads to associated neurovascular injury. In cases of suspected vascular injury, angiographic evaluation of the extremity should be carried out promptly to prevent prolonged ischemia time after injury. Any associated skin injuries should raise the suspicion of a possibility of an open fracture.
Radiographic evaluation of the injured limb should include anteroposterior (AP) and lateral radiographs of the elbow joint. In addition, forearm, wrist, and shoulder radiographs should be obtained in patients with suspected ipsilateral injuries. Other radiographic studies such as CT and MRI scans can be helpful in delineating bony and soft tissue injury. In particular, digital CT scan reconstructions in the coronal and sagittal planes can be helpful in understanding the fracture pattern and degree of fracture comminution or fragmentation. Furthermore, a recent study has shown that the addition of three-dimensional image CT scanning improves the agreement between observers evaluating fractures of the distal radius. For these reasons, CT scans can be invaluable adjuncts in the planning process before surgical fixation.
Several classification schemes have been used to describe the patterns of injury of the distal humerus. Most of the fracture classifications are morphologic and are useful largely for descriptive purposes. For the purposes of discussion within this chapter, the classification developed by the Swiss Arbeitsgemeinschaft für Osteosynthesefragen group will be used.
Fractures of the distal humerus can be generally classified into three main types. Type A or extra-articular fractures include those fractures that do not involve the joint surface. These are also described as supracondylar or transcondylar fractures. Type B fractures are articular fractures with one joint fragment in continuity with the shaft, and type C fractures are articular fractures with articular fragments with no continuity with the shaft. The two latter types (B and C) are also known as intercondylar fractures ( Fig. 78-2 ). These three types are further classified into subtypes according to degree of fracture comminution, fracture location, and degree of joint surface displacement.
There are other clinically relevant fracture types that are not categorized by this classification scheme. Isolated fractures of the distal humeral articular surfaces (capitellum and trochlea) and avulsion fractures of the humeral epicondyles (medial and lateral) are among these injuries. The treatment principles for the articular surface fractures will be discussed later in this chapter.
Fracture Management: Nonoperative and Surgical
The majority of fractures of the distal humerus require open reduction and internal fixation. Fractures that are comminuted or involve the joint surface (types B and C) typically require surgical fixation. Nonoperative treatment of these injuries will invariably result in a stiff, painful elbow. ,
Nondisplaced or minimally displaced nonarticular injuries (type A) that are stable due to the absence of fracture comminution can be treated with closed reduction under anesthesia or conscious sedation, followed by a short period of orthotic positioning or casting. The period of immobilization should not be maintained longer than 2 weeks to avoid elbow stiffness.
After the cast or orthosis is removed, treatment in a hinged elbow orthosis allows elbow joint motion while providing medial and lateral stability. The hinged brace is maintained until the fracture is healed. Close radiographic follow-up is essential during the early healing period to assure that fracture displacement beyond acceptable limits does not occur. Even though most fractures will heal with some degree of apex lateral (varus) angulation, elbow function is often acceptable.
A recent study evaluating treatment of extra-articular fractures of the distal humeral shaft with bracing in 21 adults revealed good outcomes, no incidence of nonunion, minimal angular deformity, and no restriction in ROM. Patients with severe medical problems or significant cranial or abdominal injuries who are deemed ineligible to undergo urgent surgical fixation present a difficult problem. In these cases with unacceptable operative risks, treatment of the fracture with skeletal traction may offer an alternative method of fracture alignment and stabilization. A Kirschner wire placed through the olecranon process can allow an overhead or sidearm traction apparatus to align the fracture and provide stability. The main disadvantage of this technique is the prolonged hospitalization required to achieve fracture healing while alignment is maintained.
The goals of surgical treatment are anatomic reconstruction of the fracture fragments and stable internal fixation. It is only under these conditions that an early postoperative ROM protocol can be established, minimizing the possibility of posttraumatic contracture and the development of heterotopic ossification. Displaced type A and most types B and C fractures are best treated with operative reduction and internal fixation. In the majority of cases in adults, reduction of the fracture is best undertaken with open techniques. In rare cases, closed reduction and percutaneous pinning with Kirschner wires may suffice; nevertheless, this approach is reserved in most cases for pediatric supracondylar injuries.
The principal objectives at the time of reduction are reestablishment of the distal humeral articular segment and anatomic reconstruction of the articular surface. Accurate restoration of the joint surface is crucial and one of the most important determinants of prognosis following surgical fixation of these injuries. Minor alterations or “step-off’s” of the articular surface (measuring more than 1 or 2 mm in height) can lead to the early development of osteoarthrosis of the elbow joint and subsequent functional disability. , Direct visualization of the joint surface at the time of operative reduction represents one of the most compelling reasons to treat these injuries in an open fashion.
Unless the fracture is open or there is associated vascular compromise, surgical treatment can be delayed for several days until soft tissue swelling is decreased. The extremity can be immobilized in an orthosis until the time of surgery. Preoperative planning is essential; plain radiographs and CT scans for fractures with bony comminution are indispensable. In addition, intraoperative traction films can also be helpful in delineating the degree of disruption of the articular segment.
As mentioned previously, open reduction and internal fixation is the treatment of choice for displaced fractures of the distal humerus ( Fig. 78-3 ). Surgical exposure of the fracture is achieved using the posterior approach to the elbow joint. Visualization of the distal humeral articular surface can be difficult due to the position of the olecranon process of the ulna. To overcome this problem, an osteotomy of the olecranon process can be made to improve exposure of the articular surface. Following fracture fixation, the osteotomy can be repaired using Kirschner wires or a metallic screw and stainless-steel cable in a tension band construct. This method of osteotomy fixation is rigid and allows early active motion postoperatively. A recent study of 67 patients treated with olecranon osteotomies for fixation of distal humerus fractures found no incidence of nonunion, and only 5 patients required hardware removal after the osteotomy healed. In contrast, some authors believe that olecranon osteotomies have several disadvantages and potential complications, including hardware prominence or failure and nonunion. A triceps-sparing approach to the distal humerus has been described that allows excellent visualization of the humeral articular surface, obviating the need to perform an olecranon osteotomy. While this approach was originally described for total elbow arthroplasty, its use in the treatment of traumatic injuries to the elbow is promising.
The traditional method of fixation involves the use of two metallic plates and screws. In addition to plating, interfragmentary compression of the intercondylar fracture extension is critical for reduction of the articular surface. The metallic devices that are typically used are 3.5-mm reconstruction or dynamic compression plates. More recently, devices specifically designed for the distal humerus have been made commercially available, but the advantage of these plates with their increased mechanical rigidity has not been shown in clinical practice. The advent of locking-plate technology has significantly improved the mechanical rigidity of fixation constructs. A recent study has shown that locking plates offer significant advantages in the treatment of fractures in osteoporotic bone or those in which there is significant fracture comminution. Biomechanical studies have demonstrated that two plates positioned at 90 degrees to each other offer the most stable mechanical construct for fixation of these injuries. Some authors have advocated triple plating in cases of severe osteopenia or bony comminution.
Another alternative for treatment of comminuted fractures is total-elbow arthroplasty (TEA), an option that should be reserved for the elderly or patients with low functional demands with comminuted fractures involving the joint surface. , Several studies have compared open reduction and internal fixation with TEA for the treatment of distal humerus fractures in the elderly. One study evaluating the literature found no difference between treatment options. Another study detailing the results of a randomized control trial found significantly improved functional scores in patients treated with TEA at 2 years postsurgery. Thus far, longer-term follow-up studies are necessary to evaluate the effectiveness of TEA for the treatment of distal humerus fractures.
Fractures of the Capitellum and Trochlea
Fractures of the humeral articular surface (capitellum and trochlea) commonly occur in the coronal plane and typically involve cartilage and a variable amount of subchondral bone. The mechanism of injury typically involves direct axial compression on an outstretched hand. These injuries can be missed on routine radiographic evaluation, and for this reason CT scanning is helpful in the detection of these fractures ( Fig. 78-4 ). Because of the articular involvement, any displacement of the fracture fragments requires operative fixation involving open reduction. The goal of treatment is anatomic reconstuction of the articular surface. Fixation with headless compression implants such as Herbert’s screws is the procedure of choice in the treatment of these injuries, while buried Kirschner wires offer an alternative for treatment.
Fracture Management: Nonoperative and Surgical
The results of treatment of these injuries depends largely on the residual motion of the elbow joint following surgical intervention and the postoperative rehabilitation protocol. Most of these injuries will result in some degree of limitation of the ROM of the joint. Morrey and colleagues analyzed the degree of elbow motion necessary for performing activities of daily living. The authors concluded that 130 degrees of flexion (normal, 150 degrees), 30 degrees of extension (normal, 0 degrees), 50 degrees of pronation (normal, 75 degrees), and 50 degrees of supination (normal, 85 degrees) represent the ranges at which most individuals can perform daily activities without significant limitation.
The outcomes of operative treatment of these fractures are directly related to the energy of injury. A successful result in patients with low-energy injuries is considered to be a 15-degree to 140-degree ROM. Patients with open or comminuted fractures and those with significant involvement of the articular surface will clearly have a more significant limitation in motion following treatment. Residual activity-related pain will occur in approximately one-quarter of all patients with fractures of the distal humerus.
The critical aspect of the rehabilitation process following fractures of the distal humerus and most other elbow joint injuries is the establishment of controlled motion protocols in the early postoperative or postinjury period. Prolonged immobilization following these injuries almost certainly guarantees the development of stiffness and a poor functional result. Frequent interaction and open communication between the therapist and the physician are also essential in achieving a successful result.
The rehabilitation process should begin during the first several postoperative days. A plastic molded resting orthosis is made for the patient, and active and active-assisted motion exercises in flexion-extension and pronosupination should be started by the end of the first week. Flexion exercises should be performed with the patient in the supine position with the elbow in an overhead position to allow gravity to assist in the process. Similarly, extension exercises are performed in the sitting position. The maximal ROM should be determined and maintained, while motion repetitions over the midrange will do little to improve elbow motion. Passive manipulation exercises should be avoided to prevent the formation of heterotopic ossification (HO) and anomalous muscle cocontraction. Continuous passive motion has been advocated, but the ultimate outcome has not been shown to positively affect the end ROM. Strengthening exercises should be started at 8 to 12 weeks postoperatively.
Once fracture healing has been confirmed, the use of orthoses can be very helpful in patients showing slow progress with regard to motion. Static progressive orthoses are most beneficial in improving elbow motion. Custom-made, thermoplastic turnbuckle orthoses are particularly helpful in this regard. Dynamic orthoses are often poorly tolerated by patients and often result in pain and lead to poor patient compliance. ,
Complications of Treatment
The surgical treatment of fractures of the distal humerus remains one of the most difficult challenges faced by the orthopedic surgeon. , Despite advances in the understanding and surgical care of these injuries, the rate of complications following treatment of these fractures remains high. Stiffness or contracture and exertional pain are complications that, as described in the previous paragraph, occur in a large proportion of patients with these injuries. Other complications such as wound breakdown, posttraumatic arthrosis, failure of fixation, hardware prominence, and hardware failure are typically related to the surgical technique employed at the time of surgery, and often can be avoided with the use of established technical guidelines ( Fig. 78-5 ). Other complications including fracture nonunion, , malunion, and infection are relatively uncommon but can be devastating sequelae of treatment. The development of HO and ulnar neuropathy following treatment is a complication that deserves special attention.
HO is defined as the formation of organized trabecular bone within and about the elbow joint ( Fig. 78-6 ). The formation of HO following distal humerus fractures is associated with open injuries, fracture-dislocations, delayed treatment, excessive soft tissue dissection at the time of surgery, repeat surgical procedures in the early postoperative period, and aggressive passive manipulation of the joint during the rehabilitation process. Patients with concomitant head or central nervous system injuries are especially at risk for the development of HO, with almost 90% of these patients developing periarticular bone formation in the postinjury period. This process should be distinguished from heterotopic calcification (amorphous calcium deposits about the joint also seen following traumatic injuries) and myositis ossificans (formation of organized bone within skeletal muscle following injury).