FIGURE 17-1 A–D: Mechanism patterns. A, B: The more common flexion pattern in which the condylar fragments are situated anterior to the distal shaft. C, D: An extensor pattern in which the condylar fragments are situated posterior to the distal shaft. The muscle origins on the respective condyles cause them to diverge in the coronal plane (arrows) and flex in the sagittal plane.
A T-condylar fracture may also be caused by a fall on the outstretched arm with the elbow in only slight flexion. This extension mechanism has been suggested by patients in their description of the dynamics of the fall and indirectly by the position of the distal fragments in relation to the diaphyses of the humerus—in other words, lying posterior (Fig. 17-1C, D). In the extension type of injury, the coronoid portion of the semilunar notch produces the wedge effect.
It has been suggested that contraction of the forearm flexor and extensor muscles may play a role in the displacement pattern of this fracture. Because of their origins on the epicondyles, they accentuate both the separation in the coronal plane and the forward displacement in the sagittal plane. This displacement pattern is often evident on the injury films (Fig. 17-1C, D).
Associated Injuries with T-Condylar Distal Humerus Fractures
Very little has been written on the type of associated injuries seen with T-condylar distal humerus fractures in children. In general, these are high-velocity injuries which are typically the result of high-energy mechanisms, such as motor vehicle collisions, high-speed sporting accidents or falls from significant heights.14 Open wounds, other ipsilateral upper limb injuries, and general systemic injury can occur because of the heightened energy of the trauma that occurs.
Signs and Symptoms of T-Condylar Distal Humerus Fractures
The history should focus on the mechanism and time of injury and the identification of other sites of injury. It is important to recognize any prior elbow injury or upper extremity surgery. Rounding out the history would include gathering information on pre-existing medical conditions, medication, and hand dominance.
In addition to a complete physical examination, a detailed head-to-toe trauma assessment should be completed, to rule out significant concomitant injuries to the axial and appendicular skeleton. Focused examination of the injured extremity should include inspection for bruising, swelling, deformity, and evidence of any open injuries. A thorough circumferential inspection of the elbow is critical to avoid missing open wounds, which commonly occur on the posterior aspect.20 Careful examination of distal vascular status is performed, inspecting the distal extremity for color, turgor, and palpating the radial and ulnar pulses. If there is a questionable pulse in the setting of gross malalignment of the arm, gentle longitudinal traction can be used to realign the limb and often restore the distal pulse. A detailed distal neurologic examination including motor function, hand sensibility, and two-point discrimination (median and ulnar nerves) should be performed to identify injury to the median, ulnar, radial, anterior, and posterior interosseous nerve. At the conclusion of the examination, the arm is splinted for comfort in a padded posterior, above-elbow splint.
Imaging and Other Diagnostic Studies for T-Condylar Distal Humerus Fractures
Clinically, these fractures are most often confused with extension-type supracondylar fractures. The extended position of the elbow, along with the massive swelling, is almost identical to that of the displaced extension type of supracondylar fracture.
Plain radiographs are the cornerstone to the diagnosis. In older children, the differentiation must be made from that of a comminuted supracondylar fracture. Sometimes, the diagnosis is not obvious until the fragments have been partially reduced, which allows the vertical fracture lines splitting the trochlea to become more evident. In younger children, the diagnosis is much more difficult because the articular surface is cartilaginous and not visible on plain radiographs. In addition, because of its rarity, the possibility of a T-condylar fracture may not be considered in this age group.
The diagnosis must exclude common fracture patterns of either the isolated lateral or medial condyles and complete separation of the distal humeral physis. In these latter fractures, an important sign is the presence of a medial or lateral Thurston–Holland fragment in the metaphysis.4 The key differential for the T-condylar fracture is the presence of a vertical fracture line extending down to the apex of the trochlea.
If the diagnosis is suspected after a careful evaluation of the static radiographs, it can be confirmed with a preoperative CT scan for adolescent children, MRI in younger children, or varus/valgus stress films made while the patient is under general anesthesia.4 The use of contrast medium in the form of an arthrogram intraoperative can also be helpful to distinguish fracture lines and aid in the assessment of the quality of the articular reduction.
Classification of T-Condylar Distal Humerus Fractures
Fracture Pattern
The fracture pattern in adolescents is similar to that in adults. The condylar fragments are often separated, with the articular surface completely disrupted. In addition to separation of the condylar fragments by the force of the original injury, the muscles that originate on these condylar fragments rotate them in both the coronal and sagittal planes (Fig. 17-1C, D). In the sagittal plane, the position of the condylar fragments in relation to the humeral shaft and metaphysis can either be anterior (flexor mechanism; Fig. 17-1B) or posterior (extension mechanism; Fig. 17-1D).
In skeletally immature patients, the central portions of the condylar fragments are usually separated, but the articular surface may remain intact because of its large cartilage component (Fig. 17-2).23 Thus, the disruption and displacement are primarily in the osseous supracondylar area. The elasticity of the cartilage of the distal end of the humerus often acts as an opening hinge but protects the articular surface from being completely disrupted.
FIGURE 17-2 Intact articular surface. In this T-condylar fracture in a 7-year-old boy, the thick articular cartilage remains essentially intact, preventing separation of the condylar fragments. This fracture was secured with simple percutaneous pins.
Classification
Various classifications15,27 for adult T-condylar fractures have been proposed, but there are problems with applying these classifications to children’s injuries. For example, the number of young children with this fracture is so small that it limits the experience of any one clinician in treating all types of fracture patterns. In addition, there is no useful classification for younger patients, in whom the unossified intact articular cartilage is not visible on plain radiographs. Toniolo and Wilkins30 proposed a simple classification based on the degree of displacement and comminution of the fracture fragments for pediatric T-condylar fractures. Type I fractures are minimally displaced (Fig. 17-3A, B, C). Type II fractures are displaced but do not have comminution of the metaphyseal fragments (Fig. 17-4AB). Type III fractures are displaced fractures with comminution of the metaphyseal fragments (Fig. 17-5A-F).
FIGURE 17-3 Examples of Type I T-condylar fractures. A: Lateral view of Type I undisplaced T-condylar fracture in a 6-year-old. B: AP of the t-Condylar fracture line (open arrows) was not appreciated until it healed. There are both medial and lateral Thurstan–Holland fragments (solid arrows) (Courtesy of Ruben D. Pechero, MD). C: Pre- and postoperative x-rays of minimally displaced intra-articular Type I T-condylar fracture in a 16-year-old boy treated with closed reduction and percutaneous screw fixation.
FIGURE 17-4 Type II displaced T-condylar factures. A: Type II displaced T-condylar fracture with very little metaphyseal comminution. B: Pre- and postoperative images of displaced Type II T-condylar fracture with significant displacement but no comminution, treated with olecranon osteotomy and bicolumn rigid fixation to facilitate early range of motion.
FIGURE 17-5 Type III T-condylar fractures with significant displacement and comminution. A, B: Type III—two views of markedly comminuted T-condylar fracture with multiple displaced fragments (arrows) in a 12-year-old. C–F: Pre-, intra-, postoperative, and final healed radiographs of a 12-year-old girl with displaced and severely comminuted distal humerus and ipsilateral distal radius fracture, treated with a combination of transarticular screw and cross-wire fixation. At 1 year she has made a complete recovery with comparable range of motion to her contralateral elbow.
In a child, the integrity of the articular surface may be difficult to determine without using arthrography or MRI. Because disruption of the articular surface is rare, this factor was not used in those general classification schemes. However, it is imperative to know the status of articular alignment pre- and posttreatment.
In adolescents aged 12 years or older, classification and treatment follow similar patterns to those for adults. In general intra-articular humerus fractures are defined by column (medial, lateral, or both) and degree of comminution. The Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification is used most often (Fig. 17-6). T-condylar fractures in the adolescent are usually AO C1 and C2 injuries.25 Fortunately C3 injuries with marked comminution is rare in the adolescent. Metaphyseal–diaphyseal fractures are separate entities and need to be recognized as such for proper treatment and fixation decisions.10
FIGURE 17-6 The AO classification of distal humerus fractures—fractures are classified as extra-articular, partial articular, and complete articular fracture and treatment can be tailored based on fracture classification. (Redrawn from Marsh JL, Slongo TF, Agel J, et al. Fracture and dislocation classification compendium—2007: Orthopaedic Trauma Association classification, database, and outcomes committee. J Orthop Trauma 2007;21(suppl 10):S1–133, with permission.)
Outcome Measures for T-Condylar Distal Humerus Fractures
Common clinical outcomes recorded in T-condylar distal humerus fractures include, time to union, range of motion, and elbow strength as measured through Cybex testing. Functional outcome scores for both operative and nonoperative treatments such as the Objective Functional Elbow Index6 and the Disability of the Arm, Shoulder, and Hand8 (DASH) are frequently used to measure functional improvement after upper extremity surgery.
PATHOANATOMY AND APPLIED ANATOMY RELATING TO T-CONDYLAR DISTAL HUMERUS FRACTURES
The elbow is a complex joint composed of three individual joints contained within a common articular cavity. Ossification of the distal humerus proceeds at a predictable rate. However, the rate of ossification in girls generally exceeds that of boys.9,11,12 In some areas, such as the olecranon and lateral epicondyle, the difference between boys and girls in ossification age may be as great as 2 years.11 Knowledge of the sequence and timing of ossification in the elbow will aide the treating physician in differentiating true intercondylar pathology from normal anatomic variant.
The bone of the distal humerus is triangular in shape. The medial and lateral columns of the distal humerus form the supracondylar region and are characterized by sharp and thin ridges of bone, respectively.3 At the base of the triangle lies the trochlea, which represents the most distal portion of the humerus. It is important to realize that the lateral column of the distal humerus curves anteriorly along with the anteriorly translated articular surface of the distal humerus, but the medial column is straight in line with the humeral diaphysis. The spatial relationship between the medial column, lateral column, and trochlea are conceptually similar to a spool of thread being held between the thumb and index finger.16
The surgical approach for distal humerus fractures most widely accepted is an extensile posterior incision through which all aspects of the elbow can be exposed including the anterior structures.24 The ulnar nerve is frequently a structure that needs to be identified and protected during open reduction and internal fixation. It passes through the cubital tunnel just posterior to the medial epicondyle and is held in close proximity to the distal elbow by Osborne’s fascia. Higher on the lateral side the radial nerve pierces the intermuscular septum where it is vulnerable to injury by a fracture or surgical exposure.
TREATMENT OPTIONS FOR T-CONDYLAR DISTAL HUMERUS FRACTURES
Because of the rarity of this injury, treatment recommendations are based on isolated case or small retrospective case series and/or the application of adult treatment principles.1,4,15,18,23,25,26,31 Regardless of the treatment method, certain basic principles must be considered in dealing with these fractures.
A treatment plan must be individualized for the specific fracture and the surgeon’s level of expertise and experience. The following principles must be considered in planning a treatment method:
• The T-condylar fracture is an articular fracture, so the first goal is to restore and stabilize the joint surface.
• Stability depends on the integrity of the lateral and medial supracondylar columns.
• Elbow articular mobility depends on articular congruity, correct alignment of the axis of motion, and debris- and bone-free fossae.
• Closed methods alone usually cannot produce an acceptable result because the muscle forces applied to the fragments make the fracture unstable.
• Most patients are adolescents with minimal potential for bone remodeling and should be treated with bicolumn open reduction and internal fixation similar to an adult.
• Although surgical reduction may produce an acceptable reduction on radiograph, it may add to the already extensive damage to soft tissues; this in turn can contribute to postoperative stiffness. Stable internal fixation that allows for immediate postoperative movement is important in reducing the risk of contracture development.
Nonoperative Treatment of T-Condylar Distal Humerus Fractures
Indications/Contraindications
The majority of T-condylar distal humerus fractures are best treated with some form of open reduction and internal fixation. However, there is a narrow range of fractures that are indicated for management of these injuries with closed reduction and casting. Children who are under 8 years of age with robust periosteum and essentially nondisplaced fractures are good candidates for closed reduction and casting (Table 17-1).
TABLE 17-1 T-Condylar Distal Humerus Fractures
Techniques
A very small number of T-condylar distal humerus fractures can potentially be treated with immobilization exclusively. Nondisplaced fractures can be splinted or casted until healing with close radiographic follow-up. An above-elbow cast is applied for at least 3 weeks with repeat x-rays on a weekly interval to detect interval displacement. Some clinicians perform a closed reduction for very minimally displaced fractures. Reduction under conscious sedation or anesthesia with in-line traction and live fluoroscopy is necessary to ensure that acceptable reduction is maintained. Review of reduction may be necessary with three-dimensional (3D) imaging in the form of CT or MRI. To be honest, we rarely treat fractures with any displacement closed. If a reduction is required, we view this as an unstable injury and at a minimum, will utilize three percutaneous pins to stabilize the anatomic alignment of the articular surface and both columns.
Outcomes
The majority of T-condylar distal humerus fractures are treated operatively, and therefore it is very difficult to tease out the results of nonoperative management of these fractures. In our review of several series, only 4 of 48 combined fractures were treated nonoperatively.18,23,25 In these limited cases, all patients achieved a full arc of motion without complications from their fracture or treatment.
Operative Treatment of T-Condylar Distal Humerus Fractures
Indications/Contraindications
Adolescents with T-condylar distal humerus fractures are usually treated with bicolumn open reduction and internal fixation similar to an adult. Indications for open reduction and internal fixation include all displaced extra-articular fractures, displacement of the articular surface greater than 2 mm, comminution of the distal humerus with greater than two fracture fragments, and ipsilateral fracture(s) of the upper extremity. Open fractures, pending compartment syndromes, and avascular limbs are surgical emergencies. However, the majority of T-condylar distal humerus fractures can be treated electively within 72 hours from the initial injury.
In adolescents, the majority of T-condylar distal humerus fractures are C1 according to the AO classification (Fig. 17-6). Therefore, choosing either a triceps splitting or triceps reflecting approach is sufficient to facilitate access for open reduction and internal fixation. In the rare circumstances of C2 or C3 fractures, especially in the setting of anterior comminution, an olecranon osteotomy is warranted to facilitate visualization and fixation of the articular surface.
Closed Reduction and Percutaneous Pin/Screw Fixation
In young children (<8 years) with robust periosteum, the T-condylar distal humerus fracture may represent isolated hinging of the periosteum with minimal displacement of the intercondylar fracture. Careful preoperative imaging will demonstrate merely hinging of the articular surface without significant displacement. In younger children with minimal displacement, it is not unreasonable to perform a fluoroscopic guided reduction and stabilization with multiple percutaneous pins. Generally three smooth, appropriate-sized wires are used: One horizontally from the lateral to medial to stabilize the joint surface and two to stabilize the medial and lateral columns. These pins can either be divergent lateral entry or both medial and lateral entry pins.
In older children with minimal displacement, especially single column intra-articular fractures, percutaneous reduction and cannulated column screw fixation is acceptable. This, to some degree violates standard adult principles of open reduction internal fixation. However, if anatomic articular alignment and stable internal fixation can be achieved percutaneously, then less invasive treatment is appropriate. It is critical to have superior fluoroscopic images intraoperatively to prevent the realization of persistent fracture fragment displacement and/or inadvertent screw malposition with the first set of postoperative radiographs.
Preoperative Planning. Surgical planning includes decisions on percutaneous pin versus screw fixation and patient positioning in the operative room. Careful scrutiny of preoperative radiographs and 3Dimaging (usually CT scans) is imperative. Sometimes, intraoperative fluoroscopy images with traction realignment are essential in final decision making about surgical approach and fixation methods. Percutaneous treatment should only be chosen if anatomic reduction and stable fixation can be achieved with limited postoperative immobilization to lessen the risk of elbow contracture.
Similar principles for displaced adult distal humerus intra-articular fractures are employed, with reduction and stabilization of the articular surface first, followed by stabilization of the medial and lateral columns. If percutaneous reduction and fixation is performed, a large, external bone holding the reduction clamp is used to facilitate interfragmentary reduction and compression of the joint, prior to pin or screw fixation. Accurate placement of a transverse pin to hold the articular segments in an anatomic position is critical. Depending on the degree of displacement and fracture fragment configuration, provisional or definitive fixation can be achieved with standard medial and lateral column pins as in a supracondylar humerus fracture. As noted above, in limited scenarios, these fractures can be treated definitively with closed reduction and percutaneous fixation using either smooth wires or cannulated screws (Table 17-2).
TABLE 17-2 CRPP of T-Condylar Distal Humerus Fractures
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