Supracondylar Humerus Fractures 

Distal humerus fractures in adults are relatively uncommon injuries, representing only approximately 3% of all fractures in adults. In a study from Massachusetts General Hospital of 4536 consecutive fractures in adults seen in the Massachusetts General Hospital emergency department, only 0.31% were supracondylar (bicolumn) fractures of the distal humerus. Although these injuries are relatively rare, most orthopedic surgeons are called upon to evaluate and treat patients with these injuries and, therefore, must be equipped to achieve optimal outcomes.^{[1, 2, 3]}

We live in a society with a growing elderly population and a young population in which extreme sports and high-speed motor transportation are popular; therefore, the incidence of these fractures is likely to increase. In young adults, most distal humerus fractures occur from high-energy trauma, sideswipe injuries, motor vehicle accidents, falls from heights, and gunshot wounds. In elderly persons with more osteoporotic bone, most of these injuries occur from falls.

Numerous classification schemes have been devised to categorize and discuss supracondylar fractures. In 1936, Reich originally classified supracondylar fractures into T and Y variations.^[4] In 1969, Riseborough and Raidin described 4 categories based on degree of displacement, comminution, and rotation.^[5] As surgeons became more adept at surgical reduction and internal fixation, the Arbeitsgemeinschaft für osteosynthesefragen–Association for the Study of Internal Fixation (AO-ASIF) group described a classification based on fracture pattern and degree of comminution.

AO-ASIF classification

• Type A - Extraarticular fractures

  • A1 - Epicondylar avulsions
  • A2 - Supracondylar fractures
  • A3 - Supracondylar fractures with comminution
• Type B - Unicondylar fractures

  • B1 - Fracture of the lateral condyle
  • B2 - Fracture of the medial condyle
  • B3 - Tangental fracture of the condyle
• Type C - Bicondylar fractures

  • C1 - T-shaped or Y-shaped fracture
  • C2 - T-shaped or Y-shaped fractures with comminution of 1 or 2 pillars
  • C3 - Extensive comminution of the condyles and pillars

This classification remains somewhat deficient in describing the mechanically important concept of the medial and lateral columns and their fracture involvement. It also is somewhat deficient in describing the level through which the fracture occurs in each column and related important surgical considerations. Because of these limitations, this author believes that the classification of bicolumn fractures of the distal humerus introduced by Mehne and Matta proves useful in planning bicolumn surgical fixation.

The classification of Mehne and Matta describes the specific characteristics of bicolumn fractures and allows for better preoperative planning.^[6] The classification is as follows:

• High T fracture
• Low T fracture
• Y fracture
• H fracture
• Medial Lambda fracture
• Lateral Lambda fracture

Although the medial and lateral Lambda fractures are not technically bicolumn fractures, they are included in this classification because they require similar operative fixation techniques (see image below).

Recent studies

Silva et al studied interobserver reliability (IEOR) and intraobserver reliability (IAOR) of the Baumann angle of the humerus. (The Baumann angle of the humerus is a simple, repeatable measurement that can determine outcome of supracondylar humerus fractures in children.) The Baumann angle of the humerus was measured by 5 observers on anteroposterior radiographs of 35 elbows that had sustained a nondisplaced supracondylar humerus fracture. Ranges of differences in the measurement of the Baumann angles were established, and the percentage of agreement between observers was then calculated. When the difference between observers in reported measurements of the Baumann angle was calculated to be within 7º of each other, at least 4 of the 5 observers agreed 100% of the time.^[7]

Farley et al studied the outcomes in 444 children with supracondylar humerus fractures according to the type of treating orthopedic surgeon: pediatric orthopedic surgeon or nonpediatric orthopedic surgeon. The outcome factors included open reduction rate, complications, postoperative nerve injury, repinning rate, need for physical therapy, and residual nerve palsy at final follow-up. For severe fractures, significantly more fractures were treated by open reduction in the pediatric orthopedic surgeon group than in the nonpediatric orthopedic surgeon group, but there were no other significant differences in outcomes between the 2 surgeon groups.^[8] For a comparative study of techniques for treating surpracondylar humerus fracture in children, see Pescatori et al.^[9]

Heal et al evaluated intraobserver and interobserver reproducibility of the Gartland radiographic classification for supracondylar humerus fractures in children. Anteroposterior and lateral radiographs of 50 supracondylar humerus fractures were graded on 2 occasions by 4 orthopedic surgeons according to the Wilkins modification of the Gartland classification. There was poor agreement over type I fractures; type II fractures showed fair to moderate agreement; and type III fractures and the flexion group showed good to very good agreement. Intraobserver agreement was good to very good. The authors concluded that surgeons should treat pediatric supracondylar humerus fractures on the basis of degree of displacement rather than the Gartland classification.^[10]

Surgical treatment of these fractures has evolved significantly in the last 30 years. In the 1960s and 1970s, most surgeons condemned surgical treatment because of high failure rates with loss of fixation, nonunion, and elbow stiffness. In the 1970s, treatment began to shift from casting and the "bag of bones" technique to surgical intervention with limited internal fixation. Again, results generally were poor owing to lack of adequate stabilization for early motion. In the early 1980s, the AO-ASIF group reported good and excellent results in 27 of 39 patients with comminuted fractures of the distal humerus. These by far were the best results reported in the treatment of these difficult fractures at that time. This led to an increased enthusiasm for surgical reduction and fixation. Additional surgical approaches were developed, along with more versatile fixation hardware, leading to improved surgical results.

The "bag of bones" treatment was used when bone quality or fracture pattern was not sufficient to gain stable fixation. This led to generally poor and unpredictable results. This has now largely been replaced by total elbow arthroplasty, allowing for improved and more predictable results.

Frequency

Single column fractures are relatively rare and account for only 3-5% of distal humerus fractures. Lateral column fractures are more common than medial column fractures. These fractures represent the distal extent of the respective column, including a portion of the articular surface. These are described as high or low, depending on the proximal extent of the fracture line and the extent of joint surface involvement. Milch previously described these as medial or lateral condyle fractures.^[11]

Bicolumn fractures are far more common distal humerus fractures. In some reports, these account for as many as 70% of distal humerus fractures in adults. These fractures involve disruption of both the medial and lateral columns, thus disrupting the humeral triangle and resulting in disassociation of the articular surface from the humeral shaft. Successful treatment is most challenging in these fractures.

The mechanism by which these fractures occur has been a recent topic of debate. Historically, the mechanism has been accepted to be an axial load on the elbow, with the olecranon acting as a wedge splitting the medial and lateral columns of the distal humerus. However, recent mechanical studies performed on cadavers have shown that supracondylar (bicolumn) fractures are more likely produced with the elbow flexed beyond 90° The fracture pattern produced is related to the degree of elbow flexion and the direction and magnitude of the force applied (see image below).

The clinical presentation is that of a painful swollen elbow that the patient is hesitant to move. The elbow may appear angulated and the upper extremity shortened. Some series report that open wounds are present in as many as 30% of these fractures. Patient history includes a high-energy trauma or significant fall. Evaluate adjacent joints for associated injuries.

Neurovascular status must be carefully evaluated and monitored. Owing to the close proximity of the neurovascular structures, injury is not uncommon. If a deficiency is noted, carefully evaluate and document when it first became apparent, the degree of involvement, and possible progression. If it first appeared following manipulation or splint placement, consider remanipulation, and, if the deficiency does not resolve, urgently explore to evaluate possible nerve entrapment. Neuropraxias are not uncommon and generally resolve with restoration of normal alignment and lengths. In the author's experience, resolution has occurred up to 18 months postinjury.

Radiographic evaluations should include standard anteroposterior (AP) and lateral films. With comminuted bicolumn fractures (AO-ASIF C3), repeat films following initial reduction or with longitudinal traction maintained often prove helpful to further define articular fracture fragments. For complicated fractures, CT scanning also can be helpful for surgical planning.

If vascular compromise is evident, obtain emergent arteriograms. If arterial disruption is present, obtain a vascular surgery consultation followed by immediate open reduction and internal fixation to allow for skeletal stability and support of vascular reconstruction.

Indications for surgery are to prevent further injury, restore anatomy, and provide an optimal environment for healing. If these goals are met, the patient will have the best possibility of regaining optimal function. If any surgical treatment of the distal humerus is undertaken, the goal also must be to allow adequate stability to allow for immediate range of motion. Long-term results following surgical treatment of these complex fractures have improved, largely because of improved surgical technique in gaining stability to allow for early motion. Adult elbows after such an injury are not tolerant of prolonged immobilization, and, if arthrofibrosis occurs, regaining function becomes extremely difficult if not impossible. Therefore, the goal of surgery is to stabilize to mobilize.

Fractures in which stable reduction could not be obtained were previously treated with the "bag of bones" technique. In this technique, early range of motion was allowed, without attempted reduction and fixation. This led to generally poor results, with limited motion, pain due to noncongruent joint surfaces and nonunions, and cosmetic deformity. Because of these poor results, this treatment has now for the most part been replaced by total elbow arthroplasty.^[12]

For the surgeon to properly evaluate, plan, and execute surgical treatment of these fractures, a functional and surgical understanding of the relevant anatomy is necessary. Functionally, the elbow joint behaves as a constrained hinge. The olecranon of the ulnar articulates around the trochlea of the humerus. The trochlea normally is tilted in 4° of valgus in males and 8° of valgus in females, thus creating the carrying angle of the elbow. The trochlea also is externally rotated 3-8° from a line connecting the medial and lateral epicondyles, resulting in external rotation of the arm when the elbow is flexed 90°. The images below depict relevant anatomy.

A second plane of motion occurs with the elbow joint in supination and the forearm in pronation; this range of motion is allowed by the radial head articulation with the capitellum and ulnar notch.

The surgical anatomy closely mirrors the functional anatomy. For stable elbow motion, the trochlea must be restored to its normal position, acting as a tie rod between the medial and lateral columns of the distal humerus. This forms the triangle of the distal humerus, which is crucial for stable elbow function (see image below). Both columns must be securely attached to the trochlea. Make every attempt to restore the proper valgus tilt and external rotation of the trochlea to allow for stability, full motion, and a normal carrying angle. The coronoid is important to elbow stability and should be reduced and fixated if displaced.

The olecranon fossa, a very thin wafer of bone, does not require restoration if badly comminuted. If the medial and lateral columns can be securely fixated to the trochlea, early motion should be tolerated. The medial column diverges from the humeral shaft at approximately 45°, continues, and ends in the medial epicondyle. As nothing articulates with the anteromedial epicondyle, the entire surface is available for internal fixation hardware. Be careful to protect and transfer the ulnar nerve anteriorly.

The lateral column diverges from the humeral shaft at approximately 20° and is largely cortical bone with a broad flat posterior surface, making it ideal for plate placement. At the posterior capitellum, cancellous screws must be used to avoid interrupting the anterior capitellar cartilage. Biomechanical studies have demonstrated the strongest construct of fixation of bicondylar fractures to be a direct medial plate and posterolateral plate with screws directed at 90° angles. This provides the varus and valgus rotational stability to the construct to allow for early range of motion.

Contraindications to ORIF surgical treatment include severe osteopenia, making adequate stabilization impossible. An insensate or avascular arm, which cannot be restored, makes any surgical treatment short of amputation futile. This occurs in severe sideswipes, crush, or avulsion-type injuries.

As a general rule, attempts should be made to salvage the upper extremity; even a somewhat limited arm, if sensate, is functionally better than an upper extremity prosthesis. Severe contamination or soft-tissue injury must be dealt with prior to final stabilization in order to provide an optimal environment for healing and lessen the likelihood of infection.