Closed Reduction and Percutaneous Pinning of Supracondylar Fracture of the Humerus

A supracondylar humerus fracture is an extra-articular fracture of the distal humerus at the elbow that typically occurs in children between the ages of 5 and 9 years old. This injury accounts for 50% to 70% of all elbow fractures in children and 3% to 7% of all fractures.^1,2 A supracondylar fracture of the humerus typically occurs by a fall on an outstretched hand from either furniture (beds, couches, or other objects 3-6 feet high) or playground equipment (monkey bars, slides, or swings).³

Classification

Fractures of the supracondylar humerus are first classified as either flexion or extension injuries.

• A flexion supracondylar humerus fracture is when the distal fracture is either flexed, or displaced anteriorly, to the proximal shaft of the humerus. Flexion-type supracondylar humerus fractures account for only 2% to 5% of these injuries.⁴
• More common are the extension-type supracondylar humerus fractures. Gartland originally classified extension-type fractures, and his system remains the most widely used (Figure 1).⁵
  • A Type I fractures is nondisplaced or minimally displaced.
  • A Type II fracture is a displaced fragment with an intact posterior cortex (ie, intact hinge).
  • A Type III injury is a completely displaced fragment.

There have been several modifications of the Gartland classification over the years. For example, the Type IA has been described as a truly nondisplaced fracture and the Type IB as a minimally displaced fracture with medial column comminution or varus collapse.⁶ Some clinicians distinguish between a Type IIA fracture, which is angulated with an intact hinge of bone, and a Type IIB fracture, which has a complete fracture line with displacement but with the distal fragment still touching the end of the proximal fragment. Type III injuries can also be further delineated to either posteromedial or posterolateral injuries. A recent addition to this classification is a Type IV fracture in which the distal fragment is unstable in both flexion and extension due to the loss of the periosteal attachments.⁷

Despite being commonly used descriptively, the Gartland classification is not validated, nor does it clearly guide clinical care. The senior author prefers to classify supracondylar fractures as either displaced or undisplaced.

Figure 1. Classification of supracondylar fractures of the humerus, as described by Gartland in 1959. From Herring JA: Tachdjan’s Pediatric Orthopaedics from the Texas Scottish Rite Hospital for Children: 4th ed. Philadelphia, PA: Saunders Elsevier 2008. pg 2453. Permission pending.

Indications

Summary of indications for closed reduction percutaneous pinning (CRPP):

1. Completely displaced fragment
2. Minimally displaced fragment in which capitellum is posterior to the anterior humeral line
3. Minimally displaced fragments with medial column comminution or any malalignment in the coronal plane

The rationale for closed reduction and percutaneous pinning is that the distal fragment can be controlled by the pin fixation to decrease the incidence of varus malunion, while the arm can be positioned in a comfortable semi-extended position at the elbow, avoiding discomfort and complications associated with flexing an elbow against a swollen antecubital fossa.

The American Academy of Orthopaedic Surgeons (AAOS) has recently published Guidelines on the treatment of Pediatric Supracondylar Humerus Fractures.⁸ A moderate recommendation for CRPP fixation was given to any displaced fracture (Gartland Type II and Type III). Although the initial recommendation was weak based on quality of the available literature, pin fixation with displaced fractures were superior in preventing cubitus varus and loss of motion.

Although the AAOS Guidelines did not address Type IB injuries, these injuries might have a tendency to collapse into varus due to the comminution of the medial column.^6,8 CRPP fixation of type IB fractures was also recommended if varus malunion seems possible. As a rule, minimally displaced extension-type supracondylar humerus fractures in which the capitellum is posterior to a line drawn from the anterior humeral line indicates unacceptable extension and therefore should be undergo a CRPP (Figure 2). If treated with immobilization, nondisplaced or minimally displaced supracondylar humerus fracture should be monitored with repeat radiographs after 1 week.

Figure 2.

Preoperative Planning

Prior to surgical planning for a displaced supracondylar humerus fracture, one must ensure an adequate physical exam has been performed: Because of the potential neurovascular compromise or compartment syndrome seen with this fracture pattern, an expeditious physical exam by an orthopaedic surgeon is necessary to aid in the treatment plan. If the exam reveals an abnormality in the neurovascular status, tenting of the skin, or significant edema, urgent reduction and fixation followed by a reassessment of the extremity is recommended. If there are no such concerns, immobilizing the extremity in a comfortable position will give the child some pain relief until a CRPP is scheduled. The surgeon must also ensure appropriate radiographs have been obtained to ensure correct diagnosis.

The timing of surgery of Gartland type III supracondylar fractures has been debated, as previous philosophy treated displaced fractures as emergent with immediate CRPP. Recent studies have supported urgent, rather than emergent, reduction and fixation.^9-11 We recommend that CRPP be done within 8-12 hours if there is no neurovascular compromise, tenting of the skin or worsening edema. AAOS Guidelines ⁸ could not give a recommendation on timing of reduction for displaced supracondylar humerus fractures because the published evidence base regarding this question is lacking.

Appropriate planning includes a briefing with the surgical team including nursing staff and anesthesiologist. The surgeon should communicate with the surgical team if there is a possibility of conversion to an open procedure. A tourniquet is not necessary for this procedure, and we do not recommend use of routine intravenous antibiotics prior to this procedure.¹⁰ Required equipment includes:

• Radiolucent arm board
• Image intensifier (C-arm)
• Smooth K-wires
• Power pin driver
• Plaster-of-Paris (plaster cart)

Positioning

After general anesthesia has been administered and the endotracheal tube is well secured, the patient is positioned with the entire arm on the arm board. This typically requires the patient to be moved distally on the table. We recommend securing the head adjacent to the arm board distally on the table so that when traction is applied to the affected arm, the head is not at risk of falling off the table (Figure 3). This also minimizes the empty space on the table between the head and the arm board.

Position of the equipment in the surgical theater will help ensure a smooth procedure, especially if no assistant is available. The image intensifier should be parallel to the bed and in a position to rotate (or "rainbow") for a lateral image, if necessary. Most fractures, after reduction, can rotate at the shoulder to confirm anatomic reduction in the coronal and sagittal planes without moving the image intensifier. Very unstable fractures will not tolerate rotation at the shoulder and therefore will require the image intensifier to rainbow around the arm board for the lateral view. Also, the monitor for the C-arm should be positioned in a location for easy visualization during the reduction. We recommend placing the monitor on the other side of the bed, adjacent to the image intensifier.

Figure 3.

Techniques

After a sterile skin preparation and draping, gentle traction is applied to the injured arm for 30 seconds (Figure 4). A coronal reduction should be attempted while the arm remains extended: The surgeon’s non-dominant hand secures the humeral shaft. The dominant hand holds the medial and lateral epicondyles, while applying a varus or valgus force to align the distal fragment in the coronal plane (Figure 5). More severely displaced fractures may not be amenable to initial reduction in the coronal plane.

Figure 4. After prepping and a sterile drape, 30 second of gentle traction is applied to the extremity thru the elbow

Figure 5. With the arm in extension, the medial and lateral epicondyles can be translated medially or laterally to address varus or valgus malignment. This maneuver can be performed prior to addressing the sagittal plan deformity.

For extension-type supracondylar humerus fractures, the surgeon uses the thumb of his/her dominant hand to reduce the distal fragment by applying an anterior force on the olecranon, while the non-dominant arm flexes the patient's arm into hyperflexion in one fluid motion (Figure 6). With posteromedial fragments, the forearm should be pronated during the reduction. With posterolateral displacement of the distal humerus, the forearm should be supinated during the reduction. As a general rule, the surgeon's thumb should point toward the side of the coronal displacement when performing the reduction. While maintaining the arm in a flexed position, the surgeon can confirm the reduction in both the coronal and sagittal planes by rotating the arm at the shoulder. Oblique views are also helpful to visualize any rotational deformity and the medial and lateral columns. For highly unstable fractures, the surgeon may want to avoid moving the arm and rotate the image intensifier around the arm board.

Reduction of flexion-type injuries also requires mild longitudinal traction for 30 seconds. With the patient's arm in extension, a posterior force is applied to the distal humerus. A K-wire adjacent to the posterior cortex of the humerus can be used to assist with an anterior force applied to the humeral shaft while the surgeon reduces the displaced fragment posteriorly.

An alternative approach to reduction of flexion injuries is to flex the elbow to 90 degrees and use the olecranon as a handle for the distal fragment. With one hand on the forearm shaft and one on the humeral shaft, all required translations and rotations can be gently applied to achieve a closed reduction. It is likely that the C-arm will have to be rotated to confirm the reduction, as rotating the arm often loses the reduction. Flexion fractures require open reduction more frequently than do extension injuries.

The age and size of the patient will determine the size of the K-wires used for percutaneous fixation. A 1.6-mm (0.062-in) K-wire is usually sufficient. A surgeon may want to use a smaller K-wire (1.4 mm) for a child less than 24 months, or a larger 2.0-mm K-wire for a larger child. Once a reduction is maintained in a flexed position and confirmed with fluoroscopy, a free K-wire is used to identify the first starting point. An easy way to determine the starting point is to first palpate the tip of the olecranon with the patient's arm hyperflexed. Gradually moving laterally, the surgeon will then feel the next bony prominence, the lateral condyle. An attempt should be made to place the first pin close to the midline, next to the olecranon. This is usually a good starting point. However, the surgeon may want to err slightly anterior to this point to capture the capitellum with the pin. A second pin should be placed more laterally on the lateral condyle to capture the lateral column and proximally engage the cortical shaft of the humerus. If there is still a concern regarding adequate fixation, a third lateral pin or a medial pin may be necessary.

Figure 6. Flexion reduction maneuver for extension-type of supracondylar humerus fractures. The surgeon's dominant thumb is placed on the tip of the olecranon with the fingers on the anterior aspect of the shaft of the humerus. While the non-dominant arm flexes the arm, the dominant arm forces the distal fragment anteriorly while posteriorly directing the shaft.

The ultimate goal of K-wire percutaneous fixation is to apply a stable construct. Poor pin placement is associated with loss of reduction.^11,13 Pinning stability is maximized with a large pin spread at the fracture site.; Other essential points with pin placement include ensuring that the k-wires do not exit out the fracture site, that there is bicortical purchase with both pins, and that the pins do not cross at the fracture site (Figure 7). Each of these requirements should be checked in the AP and lateral planes. Examples of optimal pin placement are seen in Figures 8, 9, and 10.

A medial pin may be necessary with unstable patterns, specifically posterolateral fragments. Care must be taken to ensure that the ulnar nerve is not injured during pin placement. If the child is small and the area is not swollen, the ulnar nerve may be palpable and a percutaneous medial pin may be placed on the anterior aspect of the medial condyle. However, if the ulnar nerve is not palpable, we recommend a small incision anterior to the medical epicondyle with blunt dissection using a hemostat. While protecting with nerve with a soft tissue guide on the K-wire, a medial pin can then safely be inserted.

Figure 7. Common causes of loss of fixation with poor pinning technique. Image A shows pin exiting through the fracture site anteriorly. Image B shows a lack of bicortical fixation. Image C has crossing of the pins at the fracture site. From Sankar 2007 JBJS, pg 716.¹³ Permission pending.

Figure 8. Two lateral pin technique for stable fixation. Note the divergence in the coronal plane and the fixation to all three columns of the distal humerus.

Figure 9. Three lateral pin technique used for more unstable patterns. The surgeon must ensure each pin has obtained bicortical fixation.

Figure 10. Some fractures patterns necessitate a medial pin. Correct medial pin placement is to err anteriorly to avoid injury to the ulnar nerve.

After fixation is obtained, dynamic visualization of the fixation is necessary under fluoroscopy. We recommend flexing and extending the arm under fluoroscopy in both planes to confirm there is no motion at the fracture site. If there is still significant motion, alternate fixation may be necessary (a third lateral pin or a medial pin). When satisfied with the reduction and fixation, the pins are cut and bent. Obtain final fluoroscopic images, as it is possible for the pins to move after they are cut and bent. A posterior slab with sidebars is applied with the arm in 60 degrees of flexion

Figure 11.

Pearls and Pitfalls

Pearls

• Anterior interosseous nerve palsy is more common in extension-type, while ulnar nerve palsy is more common in flexion-type supracondylar humerus fractures.
• An abnormal neurologic exam is closely associated with a vascular injury. Having a high index of suspicion will avoid a delayed diagnosis of a vascular injury or a compartment syndrome in the face of a presumed neuropraxia.
• Appropriately positioning the image intensifier to allow for a true lateral will be beneficial when dealing with a highly unstable fracture in which rotating at the shoulder displaces the reduction.
• While holding initial traction, a "milking" maneuver over the distal humerus may free soft tissue from the fragment and mobilize the displaced fragment.
• With hyperflexion, the fragment may displace into valgus and therefore may require a varus force applied during the flexion reduction maneuver.
• Placing the first pin through the capitellum will help obtain an ideal angle for bicortical fixation through the medial column.
• Some amount of rotational malalignment is well tolerated.
• If, after pins are placed, the fracture remains malreduced, backing up the pins to remain in the distal fragment is useful when revising the reduction.

Pitfalls

• Not positioning the head next to the arm board and then securing the patient’s head may put the head at risk of being pulled off the bed with traction.
• Avoid repeat manipulations as this may further exacerbate the swelling.
• Three poorly placed pins can still lose fixation.
• Ensure radial pulse is palpated after the reduction and fixation; a previously intact pulse may be lost if the artery becomes entrapped during the reduction.

Postoperative Care

We monitor all patients after CRPP for at least 12 hours, and typically for 24 hours if there are any concerns. We enforce strict elevation, with the hand higher than the elbow and the elbow higher than the shoulder and the heart. Pain is typically controlled with oral anti-inflammatories and narcotics. If intravenous narcotics are necessary or there is an increase in pain medication requirement, the surgeon should be notified and the splint removed for examination. There must be a heightened concern for the development of compartment syndrome with this injury.

With highly unstable fractures, we recommend follow-up and repeat radiographs at 1 week. If the fracture pattern is stable and the fixation is felt to be secure, we routinely have the patient follow up at 3-4 weeks with the pins and splint removed with radiographs. At this point, patients are allowed full range of motion. However, they are restricted from return to full activity until 2 months after the fixation. Final follow up is typically at 3 months to ensure alignment and range motion. If there were any underlying neuropathy with the injury, we would follow the patient until this resolved. If there is continued neuropathy 3 months after the injury, we would consider nerve conduction studies.

Outcome

With anatomic reduction and stable fixation, most children return to full activity with excellent outcomes and no long-term sequelae from this injury. Poor outcomes are associated with the noted complications (see below).

Complications

Vascular Injury

Vascular injury occurs to varying degrees in up to 20% of patients with a displaced supracondylar humerus fracture.^14,15 Up to a third of patients may present with a decreased or absent radial pulse; however, the hand appears to be well perfused due to the extensive collateral circulation around the elbow. In this case, an urgent, not emergent, reduction is necessary.

If there is concern regarding the perfusion of the distal extremity, we recommend emergent reduction in the operating room prior to vascular studies as this usually restores blood flow to the hand. This is also recommended by the AAOS Guideline.⁸ However, if perfusion remains inadequate after reduction, an immediate consultation with the vascular service should occur; an exploration of the antecubital fossa may be necessary.

Neurologic Injury

Neurologic injury is typically transient and can occur up to 20% of the time.^2,15 The anterior interosseous nerve is most commonly affected; however, the ulnar, medial, and radial nerves can be affected as well. Reassuring the parents is necessary. Although there is no consensus in the literature, we perform a nerve conduction study at 3 months after the injury if there is no resolution in symptoms. Even mild improvement in paresthesia would warrant continued observation and a likely resolution of the neuropraxia. A tinel’s sign progressing distally down the arm gives an excellent prognosis for nerve recovery and obviates the need for nerve conduction tests.

Compartment Syndrome

The rate of compartment syndrome following CRPP for supracondylar fracture of the humerus is 0.1-0.3%. When compartment syndrome is identified, an immediate forearm fasciotomy is required. If the diagnosis or fasciotomy are delayed, the patient will develop a Volkmann’s ischemic contracture of the forearm.

Malunion

Incidence of malunion has significantly improved with pin fixation. Cubitus varus or cubitus valgus may be cosmetically, but not functionally, problematic to the patient and his/her parents. An osteotomy is necessary to correct this malunion.

Pin Site Infection

Varying incidence of pin site infection, from <1% to 6.6%, have been reported. Infections typically resolve promptly with oral antibiotics with or without pin removal as indicated.^2,15

Elbow Stiffness

Children are usually resilient and will resolve this stiffness without formal physiotherapy. Rarely, physiotherapy is necessary to improve overall range of motion.

References

1. Landin, L.A., 1983. "Fracture patterns in children. Analysis of 8,682 fractures with special reference to incidence, etiology and secular changes in a Swedish urban population 1950-1979." Acta Orthop Scand Suppl. (202): 1-109.
2. Tachdjian's Pediatric Orthopaedics from the Texas Scottish Rite Hospital for Children, H. J.A., Editor, Saunders Elsevier: Philadelphia, PA. 2008. 2451-2479.
3. Farnsworth C.L., P.D. Silva, Mubarak S.J., 1998. "Etiology of supracondylar humerus fractures." J Pediatr Orthop. 18(1): 38-42.
4. Otsuka N.Y., J.R. Kasser, 1997. "Supracondylar Fractures of the Humerus in Children." J Am Acad Orthop Surg, 5(1): 19-26.
5. Gartland J.J., 1959. "Management of supracondylar fractures of the humerus in children." Surg Gynecol Obstet, 109(2): 145-54.
6. Mubarak S.J., Davids J.R., 1994. "Closed Reduction and percutaneous pinning of supracondylar fractures of the distal humerus in the child.  In Morrey BF (ed.):  MasterTechniques in Orthopaedic Surgery - Elbow."  New York, Raven Press, 37.
7. Leitch K.K., Kay R.M., Femino J.D., Tolo V.T., Storer S.K., Skaggs D.L., 2006. "Treatment of multidirectionally unstable supracondylar humerus fractures in children:  A modified Gartland type-IV."  Journal of Bone and Joint Surgery Am, 88(5): 980-985. 
8. The Treatment of Pediatric Supracondylar Humerus Fractures:  Evidence-Based Guideline and Evidence Report, AAOS, Editor 2011, American Academy of Orthopaedic Surgeons: Rosemont, IL.
9. Gupta, N., et al. 2004. "Effect of surgical delay on perioperative complications and need for open reduction in supracondylar humerus fractures in children." J Pediatr Orthop,24(3): 245-8.
10. Iyengar, S.R., S.A. Hoffinger, D.R. Townsend, Early versus delayed reduction and pinning of type III displaced supracondylar fractures of the humerus in children: a comparative study. J Orthop Trauma, 1999. 13(1): p. 51-5.
11. Leet A.I., Frisancho J, Ebramzadeh E, 2002. "Delayed treatment of type 3 supracondylar humerus fractures in children."  J Pediatr Orthop. 22(2): 203-7.
12. Bashyal R.K., et al., 2009. "Complications after pinning of supracondylar distal humerus fractures." J Pediatr Orthop. 29(7): 704-8.
13. Sankar W.N., et al. 2007. "Loss of pin fixation in displaced supracondylar humeral fractures in children: causes and prevention." J Bone Joint Surg Am, 89(4): 713-7.
14. Skaggs D.L., et al., 2008. "How safe is the operative treatment of Gartland type 2 supracondylar humerus fractures in children?" J Pediatr Orthop, 28(2): 139-41.
15. Omid R.,Choi PD., Skaggs D.L, 2008. "Supracondylar humeral fractures in children." J Bone Joint Surg Am, 90(5): 1121-32.