Joaquin Sanchez-Sotelo
PATIENT HISTORY AND PHYSICAL FINDINGS
Distal humerus fractures occur in two age groups:
Younger patients who sustain high-energy trauma
Older patients with underlying osteopenia
Comminution is the dominant feature of supracondylar and intercondylar fractures and complicates internal fixation.
The goals of the initial evaluation are to:
Understand the fracture pattern.
Determine the existence of previous symptomatic elbow pathology.
Determine the extent of associated soft tissue (open fractures).
Identify associated musculoskeletal or neurovascular injuries.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Elbow radiographs in the anteroposterior and lateral planes are the first imaging studies obtained and should be carefully scrutinized to identify the fracture lines and fragments as well as the extent of comminution.
A complete understanding of the fracture pattern is difficult to obtain based only on simple radiographs because of the complex geometry of the distal humerus and fragment overlapping (FIG 1A,B).
CT with three-dimensional reconstruction is extremely helpful, especially in the more complex cases. It allows the surgeon to look for specific fractured fragments at the time of fixation, facilitating accurate fracture reduction (FIG 1C,D).
Traction radiographs obtained in the operating room with the patient under anesthesia just before surgery also can be helpful, especially if a CT scan is not available.
SURGICAL MANAGEMENT
Internal fixation is the treatment of choice for most fractures of the distal humerus.
Modern fixation techniques seem to benefit from.
Fixation strategies designed to improve the mechanical stability of the construct
Use of precontoured periarticular plates
Use of screws locked to the plates
Elbow arthroplasty should be considered in elderly patients with previous elbow pathology or in very low, comminuted fractures in patients with osteopenia.
The goal of the internal fixation technique is to achieve a construct stable enough to allow immediate unprotected motion without fear of redisplacement.12 This can be attained in most distal humerus fractures—even the most complex— provided the following principles are adhered to (FIG 2):
Plates used for internal fixation are applied so that fixation in the distal fragments is maximized.
Distal screw fixation contributes to stability at the supracondylar level, where true interfragmentary compression is achieved.
Approaches
Adequate exposure is necessary to achieve satisfactory reduction and fixation.
Subcutaneous transposition of the ulnar nerve is associated with a decreased incidence of postoperative ulnar neuropathy.
FIG 1 • A,B. AP and lateral radiographs showing a comminuted intra-articular supraintercondylar fracture of the distal humerus. The complexity of the fracture is difficult to appreciate fully because of the geometry of the distal humerus, fracture comminution, and fragment overlapping. C,D. The use of CT with three-dimensional reconstruction and surface rendering helps understand the fracture configuration and anticipate the surgical findings.
FIG 2 • A. Internal fixation using two parallel medial and lateral plates allows maximal fixation of the plates in the distal fragments and increased stability at the supracondylar level. B. This postoperative AP radiograph shows anatomic reduction of a complex distal humerus fracture and stable fixation using the principles and technique described in this chapter. The olecranon osteotomy was fixed with a plate. (A:Copyright Mayo.)
Most fractures require mobilization of the extensor mechanism of the elbow through an olecranon osteotomy, triceps reflection, or triceps split.
Simple fractures occasionally may be addressed working on both sides of the triceps without mobilization of the extensor mechanism.
Olecranon osteotomy is the preferred surgical approach for internal fixation for most distal humerus fractures.11
Advantage.
Provides excellent exposure
Offers the potential of bone-to-bone healing, thereby limiting the risk of triceps dysfunction
Disadvantage.
Complications: nonunion, intra-articular adhesions
Hardware removal may be needed.
Limits the ability for intraoperative conversion to elbow arthroplasty
May devitalize the anconeus muscle
The proximal ulna cannot be used as a template to judge reduction and motion.
Triceps reflection and triceps split8 allow preservation of the intact ulna.
Avoids complications related to olecranon osteotomy
Facilitates intraoperative conversion to total elbow arthroplasty
Allows use of the proximal ulna as a template for reduction of the distal humerus articular surface
Allows assessment of extension deficit after fracture fixation, which is especially useful in fractures requiring metaphyseal shortening
Bilaterotricipital approach1
Goals and indications
The goal is to provide adequate exposure for fracture fixation without violating the extensor mechanism.
This approach is used only for the more simple fracture patterns (eg, extra-articular or simple intra-articular distal humerus fractures [AO/OTA A, C1, C2]) or when elbow arthroplasty is being considered.
Advantage.
This approach avoids complications related to the extensor mechanism.
No postoperative protection is needed.
Surgical time is decreased.
Disadvantag.
The procedure provides limited exposure of the articular surface.
TECHNIQUES
SURGICAL APPROACH
Olecranon Osteotomy
Chevron osteotomy provides increased stability (TECH FIG 1A).
The distal apex of the chevron osteotomy is centered with the bare area of the olecranon articular surface.
The anconeus is divided with electrocautery in line with the lateral limb of the osteotomy.
Alternatively, the anconeus may be preserved by dissecting it free on its distal aspect and reflecting it proximally attached to the proximal ulnar fragment.2
Start the osteotomy with a thin oscillating saw.
Complete the osteotomy with an osteotome.
Decreases risk of damage to the articular cartilage on ulna and humerus
Creates irregularities at the opposing cut surfaces, which may increase interdigitation
Mobilize the fragment to facilitate exposure (TECH FIG 1B).
Fixation (TECH FIG 1C)
Some biomechanical studies support the combination of a 7.3-mm cancellous screw and tension band over either a screw alone or K-wires plus tension band; others have found no differences.
The author's preferred method uses K-wires plus a tension band.
If screw fixation is planned, drill and tap the ulna before performing the osteotomy.
Plate fixation is preferred by some.
It provides improved fixation, but the risk of wound complications is increased.
Triceps Reflection and Triceps Split
Bryan-Morrey triceps-sparing approach (TECH FIG 2)
The triceps is elevated from the medial intermuscular septum.
The forearm fascia and periosteum are incised just lateral to the flexor carpi ulnaris.
The triceps, forearm fascia, and anconeus are elevated in continuity from medial to lateral.
TECH FIG 1 • Olecranon osteotomy provides an excellent exposure for distal humerus fracture fixation. A. A chevron osteotomy is initiated with a microsagittal saw and completed with an osteotome. Drilling and tapping before performing the osteotomy facilitates fixation of the osteotomy if screw fixation is selected. B. Proximal mobilization of the osteotomized fragment and triceps allows ample exposure of the articular surface and columns. C. Fixation may be performed with a cancellous screw and tension band, wires and a tension band, or a plate.
The anterior bundle of the medial collateral ligament and the lateral ulnar collateral ligament must be preserved to avoid postoperative instability.
Mayo-modified extensile Köcher approac.
The triceps is elevated from the lateral intermuscular septum.
The triceps and anconeus are elevated in continuity from lateral to medial.
TECH FIG 2 • The extensor mechanism (ie, triceps, anconeus, and forearm fascia) may be elevated off the ulna subperiosteally in continuity from medial to lateral (Bryan-Morrey approach) or from lateral to medial (Mayo-modified extensile Köcher approach).
As noted earlier, the anterior bundle of the medial collateral ligament and the lateral ulnar collateral ligament must be preserved to avoid postoperative instability.
Bilaterotricipital Approach
The triceps is elevated from the medial and lateral intermuscular septae.
Lateral dissection can be extended anterior to the anconeus muscle (TECH FIG 3).
Arthrotomy is performed posterior to the medial collateral ligament and lateral collateral ligament complex.
TECH FIG 3 • Fractures with no or limited articular involvement may be fixed working on both sides of the triceps. As shown in this image, the extensor mechanism is left mostly undisturbed.
INTERNAL FIXATION
Technical Objectives
Screws in the distal fragments (articular segment) should be placed according to the following principles:
Every screw should pass through a plate.
Each screw should engage a fragment on the opposite side that also is fixed to a plate.
As many screws as possible should be placed in the distal fragments.
Each screw should be as long as possible.
Each screw should engage as many articular fragments as possible.
The screws should lock together by interdigitation within the distal segment, thereby rigidly linking the medial and lateral columns together, creating an architectural structure similar to that of an arch or dome.
Plates are used for fixation.
Plates should be applied such that compression is achieved at the supracondylar level for both columns.
Plates must be strong enough and stiff enough to resist breaking or bending before union occurs at the supracondylar level.
Provisional Assembly of the Articular Surface and Plate Placement
Reduce the articular surface fragments anatomically.
The proximal ulna and radial head may be used as templates.
Rotational alignment should be carefully assessed.
Use smooth K-wires to maintain the reduction provisionally (TECH FIG 4A).
Two 2.0-mm smooth wires introduced at the medial and lateral epicondyles facilitate provisional placement of the plates and can be replaced by screws later.
Fine-threaded wires or absorbable pins may be used for definitive fixation of small fracture fragments.
Medial and lateral plates are placed so that one of the distal holes of each plate slides over the medial and lateral 2.0-mm smooth wires introduced at the medial and lateral epicondyles (TECH FIG 4B).
One cortical screw is loosely introduced into a slotted hole of each plate to hold the plates in place; use of slotted holes for these screws facilitates later adjustments in plate positioning.
Articular and Distal Fixation
Two or more distal screws are inserted through the plates medially and laterally. As noted, the screws should be as long as possible and engage the opposite column.
Before screw application, a large bone clamp is used to compress the articular fracture lines, unless there is comminution of the articular surface.
The two 2.0-mm smooth pins may be replaced with distal screws without previous drilling, to avoid accidental breakage of the drill when contacting the other screws. Usually, these last screws will interdigitate with the previously applied distal screws, thereby increasing the stability of the construct (TECH FIG 5).
Supracondylar Compression and Proximal Plate Fixation
The proximal screw on one side is backed out, and a large bone clamp is applied distally on that side and proximally on the opposite side to apply maximum compression at the supracondylar level. Compression is maintained by application of one proximal screw in the compression mode (TECH FIG 6A,B).
The same steps are followed on the opposite side.
TECH FIG 4 • A. Anatomic reduction of the articular surface is maintained provisionally with fine wires placed so that they will not interfere with plate and screw application. B. The medial and lateral plates are held in place provisionally with two distal 2.0-mm pins (which later will be replaced by screws) and two proximal screws through an oval hole to allow small adjustments in plate positioning. (Copyright Mayo.)
TECH FIG 5 • Maximal distal plate anchorage is then achieved by insertion of multiple long screws through the plates and into the distal fragments. Usually the screws from the medial and lateral directions will engage, creating an interlocked structure that increases fracture stability. (Copyright Mayo.)
The remaining diaphyseal screws are then introduced, providing additional compression as they push the undercontoured plates to gain intimate contact with the underlying bone (TECH FIG 6C,D).
Small posterior fragments can be fixed with threaded wires or absorbable pins.
Provisional wires are removed.
The elbow is put through range of motion. Motion should be smooth. If extension is limited, the tip of the olecranon may be removed.
TECH FIG 6 • A,B. Supracondylar compression is achieved with the use of a large clamp, insertion of screws in the compression mode, and slight undercontouring of the plates. The same technique is applied laterally and medially. C. Internal fixation of a complex distal humerus fracture. (A,B: Copyright Mayo.)
SUPRACONDYLAR SHORTENING
In cases with supracondylar comminution (ie, bone loss), compression at the supracondylar level cannot be achieved unless the humerus is shortened into a nonanatomic reduction that will provide adequate bone contact (TECH FIG 7A,B).
The humerus may be shortened between a few millimeters and 2 cm with only minor losses in extension strength.9
Bone is trimmed from the diaphysis to ensure adequate bone contact with the distal fragments.
The distal fragments are translated proximally and anteriorly. Anterior translation is necessary to create room for the radial head and the coronoid in flexion.
The fracture is fixed in the desired position using the technique described previously.
A new deep and wide olecranon fossa is created by removing bone from the distal and posterior aspect of the diaphysis (TECH FIG 7C). Otherwise, extension will be restricted.
TECH FIG 7 • In cases of severe supracondylar comminution, adequate interfragmentary contact and compression takes priority over anatomic reduction. The humerus may be shortened anywhere from a few millimeters to 2 cm by trimming the bony spikes of the diaphysis (A), advancing the distal segment proximally and anteriorly, and fixing it in a nonanatomic fashion (B). C. The olecranon fossa is recreated in this case by removing bone from the posterior aspect of the diaphysis with a burr. (A,B: Copyright Mayo.)
PEARLS AND PITFALLS
POSTOPERATIVE MANAGEMENT
After closure, the elbow is placed in a bulky noncompressive dressing with an anterior plaster splint to maintain the elbow in extension, and the upper extremity is kept elevated.
Motion is initiated according to the extent of soft tissue damage. Motion usually can be initiated on the first or second postoperative day, but it may be necessary to wait for several days in the case of open fractures or severe soft tissue damage.
Most patients benefit from a program of continuous passive motion for the first week or two after fixation; some may benefit from a longer period of passive motion.
When postoperative motion fails to progress as expected, a program of patient-adjusted static flexion and extension splints is implemented.
Treatment with indomethacin or single-dose radiation to the soft tissues shielding the fracture site may be considered for patients with high risk of heterotopic ossification, such as those with associated head or spinal trauma as well as those who require several surgeries in a short period of time.
OUTCOMES
The results of internal fixation for fractures of the distal humerus using modern techniques are summarized in Table 1.
The results of the different studies are difficult to interpret, because the severity of the injuries included cannot be compared, and there may be variations in the accuracy of range-of-motion measurements.
Improvements in fixation techniques have resulted in a decreased rate of hardware failure and nonunion, but range of motion is not reliably restored in every patient.
COMPLICATIONS
Infection
Nonunion
Stiffness, with or without heterotopic ossification
Need for removal of the hardware used for fixation of the olecranon osteotomy
Posttraumatic osteoarthritis or avascular necrosis requiring interposition arthroplasty or elbow replacement
REFERENCES
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