Oblique Supracondylar Humerus Fracture
Oblique supracondylar humerus fractures represent a subset of supracondylar fractures with additional inherent instability due to their fracture orientation and may present with significant shortening and rotational deformity (Zorrilla et al., Int Orthop 39(11):2287–2296, 2015). Closed reduction and percutaneous fixation of closed injuries remains the standard of care, and open reduction is rarely necessary. However, special attention is required to the medial and lateral columns during reduction and fixation, as well as to the posterior cortex, if there is also a sagittal oblique component to the fracture (Jaeblon et al., J Pediatr Orthop 36(8):787–792, 2016). Depending on the obliquity of the fracture, the lateral-entry pinning technique may need to be modified (Feng et al., J Pediatr Orthop 32(2):196–200, 2012; Wang et al., J Pediatr Orthop 21(6):495–498, 2012). After successful closed reduction, Kirschner wire fixation with 0.062 in or 0.078 in pins in either crossed-pin or lateral-only configuration is acceptable, with the goal of maximizing pin spread at the fracture site and adequate fixation of the medial and lateral columns (Iobst et al., J Orthop Trauma 32:e492–e496, 2018; Bahk et al., J Pediatr Orthop 28(5):493–499, 2008). The postoperative course is comparable to transverse supracondylar fractures, with x-rays 1–1.5 weeks postoperatively to ensure maintenance of alignment and pin removal in the office at 3–4 weeks post-op (Reisoglu et al., Acta Orthop Traumatol Turc 51(1):34–38, 2017).
1 Brief Clinical History
A 7-year-old female who fell onto outstretched left arm on the playground and had immediate pain and swelling, as well as paresthesia’s of the hand. She was seen in the Emergency Department where x-rays were taken showing an extension-type supracondylar humerus fracture with 100% displacement, as well as greenstick fractures of distal radius and ulna metaphyses without significant displacement. She was examined by the on-call orthopedic resident, who noted her inability to flex her left index finger DIP or thumb IP joint, consistent with an anterior interosseous nerve (AIN) palsy. She did have palpable radial and ulnar pulses upon presentation. She had exquisite tenderness over her fracture sites, but no injuries elsewhere on secondary examination. Due to her displaced supracondylar humerus fracture with associated nerve palsy, as well as ipsilateral forearm fractures, she was considered at high risk for developing compartment syndrome and was therefore taken to the operating room that evening for fixation. She underwent closed reduction and percutaneous pinning of her oblique supracondylar fracture, followed by closed reduction of her greenstick-type forearm fractures, and healed uneventfully with pins removed at 30 days post-op. She recovered AIN function following surgery.
2 Preoperative Clinical Photos and Radiographs
3 Preoperative Problem List
Gartland type 3 supracondylar humerus fracture with oblique fracture orientation
Distal radius and ulna metaphyseal greenstick fractures with mild apex volar angulation
“Floating” elbow due to fractures proximal and distal to elbow joint
4 Treatment Strategy
Supracondylar humerus fractures are extremely common upper extremity injuries in children, and the severity of these injuries is variable (Zorrilla et al. 2015). Due to the fracture location, displacement can result in injury to the neurovascular structures traversing the fracture site, and the incidence of neurovascular injury increases with greater fracture displacement (Zorrilla et al. 2015). Although we normally rely on active patient participation and cooperation to assess neurovascular status, this is often not possible due to young age of the patient, combined with the pain and anxiety associated with injuries that are grossly clinically deformed. For this reason, if a reliable exam is not possible, it is best to proceed with treatment as though there were neurovascular injury present in displaced fractures.
The most useful classification system for extension-type supracondylar humerus fractures is the Gartland classification (Zorrilla et al. 2015). This separates fractures which are non-displaced (type 1), from fractures with intact posterior hinge (type 2), and fractures with 100% displacement (type 3). Some have suggested that a fourth type exists, with complete periosteal disruption and buttonhole displacement of the proximal fragment into the antebrachial musculature anteriorly.
Since Gartland type 3 fractures are more likely to be associated with neurovascular injury, they are typically expedited for surgical treatment (Zorrilla et al. 2015). Additionally, “floating” elbow injuries with ipsilateral forearm fractures and supracondylar humerus fracture are considered extremely unstable and warrant more urgent intervention (Blumberg et al. 2018). If the extremity is cold and pulseless distally, this is an urgent indication for surgery, but pink, pulseless extremities can typically be watched closely for several hours before treatment (Zorrilla et al. 2015). Our patient did present with an AIN palsy, pushing us to take her to the operating room that evening.
All supracondylar humerus fractures that are displaced require closed reduction and percutaneous pin fixation, and if a closed reduction is not possible, then open reduction is warranted (Zorrilla et al. 2015). Whether ipsilateral forearm fractures require fixation, as well as reduction, remains controversial, but current thinking is that stable forearm fractures do not require pinning in “floating” elbow injuries (Blumberg et al. 2018).
Plain radiographs are sufficient for preoperative planning. No advanced imaging is necessary. From the preoperative x-rays shown above, it is clear that there is a Gartland type 3 supracondylar humerus fracture with coronal and sagittal plate obliquity, and from this alone, we can anticipate that the fracture will be more unstable to shear forces than a typical type 3 fracture and that this pattern will be more susceptible to extension and rotational malunion (Bahk et al. 2008).
The most important factor in preventing the development of compartment syndrome and subsequent Volkmann contracture with these injuries is to avoid immediate circumferential fiberglass or plaster casts (Blumberg et al. 2018). The decision to treat the forearm fractures versus the supracondylar fracture first is simply surgeon preference.
Closed reduction under fluoroscopic guidance is always attempted first, prior to making an open approach to the fracture. A “milking” maneuver or use of an Esmarch bandage wrapped about the elbow from proximal to distal can be helpful in the initial stage of the closed reduction to establish the correct length of the distal humerus. Next, varus and valgus stress at the fracture site can improve the angulation of the fracture in the frontal plane, as well as direct manual translation of the distal fragment in the medial or lateral direction. Pronation and supination of the forearm can aid in reducing lateral or medial gapping, respectively, and also can improve rotational alignment. The key maneuver in reducing extension-type supracondylar fractures is elbow flexion with direct pressure on the olecranon process while maintaining the pronated or supinated forearm alignment necessary for rotational stability. Care must be taken not to be too forceful with this flexion maneuver, as an extension-type supracondylar fracture can easily be converted to a flexion-type fracture, which is notoriously more difficult to reduce, especially with an oblique fracture orientation (Bahk et al. 2008).
Assessment of fracture reduction is necessary prior to fixation across the fracture with hardware. The AP view is often difficult to interpret due to superimposition of the proximal radius and ulna on the image, so internal and external oblique x-rays are useful to assess the integrity of the lateral and medial columns, respectively (Zorrilla et al. 2015). The lateral view can be obtained by moving the patient’s arm while maintaining maximum elbow flexion and forearm rotation, or alternatively the c-arm can be manipulated.
The closed reduction is held in place with lateral-entry 0.062 in Kirschner pins. The typical order of pin placement begins with the lateral-most starting point on the capitellum up the lateral column of the distal humerus first, followed by a second pin beginning with a more medial start point and aiming more horizontally toward the medial column. A third pin can be placed between the first two. During pin placement, AP and lateral views are taken to ensure that all pins cross the fracture site, with the goal of maximum spread at the fracture. The choice to use a medial pin is surgeon dependent, with increased risk of ulnar nerve injury but increased biomechanical construct strength with the use of a medial pin. Medial pins can be placed percutaneously with the elbow extended and protection of the ulnar nerve with a thumb holding the nerve posterior to the medial epicondyle or by making a small incision over the medial epicondyle and using a soft tissue protector while placing the pin.
In oblique supracondylar fractures, the use of a 2.0 mm pin or inserting the pin on “oscillate” mode can prevent bounce off the opposite cortex (Iobst et al. 2018). Additionally, a recent biomechanical study demonstrated that for lateral oblique fractures (such as in our patient), three lateral divergent pins provided no benefit over two lateral pins, and the only modality in which two crossed pins was superior to two lateral pins was in valgus stress (Feng et al. 2012).
However, in medial oblique fractures, or “reverse obliquity” fracture patterns, another biomechanical study demonstrated superiority of crossed pins over any lateral pin configuration in all loading conditions (Wang et al. 2012). If our fracture had been a reverse obliquity pattern, placement of lateral-entry pins may have been difficult, and medial-entry pins would have been favored.
The vascular status of the extremity is always assessed prior to completion of the procedure. If pulses are neither palpable nor dopplerable, this is an indication to remove the pins and explore the brachial artery (Zorrilla et al. 2015).
After closed reduction of the minimally displaced forearm fractures, long-arm cast placement is acceptable if the cast is bivalved to accommodate swelling (Blumberg et al. 2018). A noncircumferential posterior long-arm splint would also be an acceptable mode of immobilization for the 1st week after surgery (Blumberg et al. 2018).
Postoperatively, patients require close monitoring for frequent neurovascular checks to avoid the dreaded complication of compartment syndrome (Zorrilla et al. 2015). Patients are typically kept inpatient for 24 h for more severe-type injuries, especially if a preoperative neurapraxia is present.
Patients are seen 1–1.5 weeks after surgery for x-rays to determine if alignment has maintained and then at 3–4 weeks postoperatively for pin removal in the office (Zorrilla et al. 2015; Reisoglu et al. 2017). At that time, a determination is made based on x-ray healing and clinical tenderness over the fracture site whether an additional period of casting is needed. The risk of prolonged immobilization is elbow stiffness (Zorrilla et al. 2015).
5 Basic Principles
Longitudinal traction at 20–30° of elbow flexion
Esmarch proximal to distal, “milking maneuver” to establish fracture length
Varus/valgus force to correct angulation
Manual translation of distal fragment
Pronation/supination to correct gapping laterally or medially, respectively, or rotational alignment
Flexion with thumb on olecranon process while holding pronosupination
Checking AP, lateral, and medial and lateral oblique views for column assessment
Convert to open reduction if unable to achieve adequate reduction closed
Use 0.062 in or 0.078 in Kirschner pins, 0.054 in only in very small children.
Larger pin or insertion on “oscillate” mode to prevent bounce off opposite cortex.
Maximize distance between pins at fracture.
Lateral-entry pins first, begin with lateral column pin.
For medial oblique fracture, medial-entry pins provide more stability than lateral-entry pins.
For lateral oblique fracture, lateral-entry pins provide more stability than medial-entry pins.
Two crossed pins are always a stable configuration.
Risk of ulnar nerve injury or stretch over medial pin.
6 Images During Treatment
7 Technical Pearls
Correct sequence of reduction maneuvers, with flexion last
Lateral pins first
Maximum angle to prevent wire “bounce” off opposite cortex 68° (0.062) or 74° (0.078)
Extension of the elbow for placement of medial pin, if needed
Recognition of especially unstable fracture patterns
8 Outcome Clinical Photos and Radiographs
9 Avoiding and Managing Problems
Achieving and maintaining anatomic reduction is the most challenging aspect of treating oblique supracondylar humerus fractures due to their inherent instability to shear forces (Reisoglu et al. 2017). Medial comminution can also lead to varus collapse (Zorrilla et al. 2015; Reisoglu et al. 2017). Ensuring adequate alignment prior to percutaneous pin fixation is critical. If near-anatomic alignment cannot be achieved with closed reduction, an open approach may be used for direct reduction, but this is rarely necessary (Zorrilla et al. 2015). X-rays should be taken at 1–1.5 weeks postoperatively to determine if alignment has been maintained or lost (Reisoglu et al. 2017). At this time, if needed, the patient can be taken back to surgery for revision reduction and fixation without the need for osteotomy. Pin site infections are rare, but are typically managed with oral antibiotics and removal of the pin, if loose (Zorrilla et al. 2015).