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Supracondylar Fractures
Of the Humerus in Children
Principles of Management
Kaye E. Wilkins, M.D.
Professor, Orthopedics and Pediatrics
University of TexasHealthScienceCenter at San Antonio
Mail Code 7774 - 7703 Floyd Curl Drive
San Antonio, Texas 78229-3900
Supracondylar Fractures of the Humerus in Children
Principles of Management
I. Incidence
1. At what age do they most commonly occur?
They peak at 7 years of age.(KA01).
2. Why is the peak incidence at 7 years of age?
When a child falls on its extended upper extremity those patients who demonstrate hyperextension (cubitus recurvatum) (CH01, NO99) of the elbow are more predisposed to have supracondylar fractures. Those children who do not have hyperextension of the elbow tend to sustain fractures of the radius and the ulna, usually in the distal portion.
3. What other factor at this age contributes to the increased incidence of humeral fractures in the supracondylar area?
Because of growth, this supracondylar area is composed of weak, remodeling, metaphyseal bone. The cortices are very thin.
II. Mechanism of Injury
4. What is the mechanism of injury for extension type supracondylar fractures?
Hyperextension of the elbow joint and weakened metaphyses, fractures are common in this age group. When the child falls, they usually extend the non-dominated upper extremity to catch themselves.
If they exhibit hyperextension, the olecranon is able to penetrate deeply to its fossa, which concentrates all the bending forces at the supracondylar area. Since at this age the supracondylar area is weakened metaphyseal bone, it resists the extension forces poorly and thus fails easily.
The are three different stages of failure:
1. Almost none or break in the anterior cortex;
2. A partial break in the distal humerus but leaving some of the posterior cortex intact;
3. A complete displacement with various degrees of separation of the fracture fragments.
These account for the three Gartland types (GA59, KA01).
III. Classification
5. To what two major sub-types are supracondylar fractures classified?
They are classified into two major subtypes:
Extension type - in which the distal fragment is displaced posteriorly and the apex of the fracture site is .Ninety to ninety-five percent of all supracondylar fractures are extension type.
The other, less common, type of supracondylar fractures is the Flexion type in which the apex of the fracture site is posterior. These account for anywhere to 1-5 % of all supracondylar fractures (CH01, KA01).
6. How are the extension type supracondylar humeral fractures commonly classified?
The classification is based upon the original description reported by Gartland in 1959 (GA59). These types represent no more than the three stages of displacement that are:
Type I – no displacement, i.e., none or little displacement, which will result in an acceptable functional and cosmetic outcome.
Type II – incomplete displacement in which there is enough intrinsic stability that the fracture can easily be managed by closed reduction and cast applications.
Type III – complete or sufficient displacement that the fracture cannot be stabilized by a cast alone but requires some type of surgical stabilization.
7. Why all the emphasis on the classification?
It dictates the method of treatment as will be seen in the following discussions.
IV. Extension Type Supracondylar Fractures
A.Treatment
Type I Fractures
8. What are the criteria for Type I Fractures?
- It is essentially undisplaced or very minimally displaced
- There is significant displacement of the posterior and anterior fat pads. In fact this may be the only sign, as the fracture may not be apparent on routine radiographs.
- The determination as to whether there is an acceptable alignment, at least in the saggital plane, is that the anterior humeral line still goes through the ossific nucleus of the capitellum and there is no “crescent sign” or superimposition of the distal end of the capitellum over the olecranon indicating varus alignment.
9. Post fracture, if no fracture was seen on the original radiographs how does one confirm that the patient did indeed have an occult Type I supracondylar fracture?
There will usually be periosteal new bone formation seen at the edges of the metaphyseal cortices appearing about 2-3 weeks post injury.
10. How are Type I Fractures usually treated?
The extremity is placed in some type of protective immobilization for three weeks. This can be in the form of a cast or splint at 90 degrees or less.
11. What positions need to be avoided?
Two positions need to be avoided, that is hyperpronation and hyperflexion (BA02) by Mapes and Hennrikus (MA98) it was shown that there was a decrease in the blood flow to the distal portion of the forearm when the elbow was hyper flexed and the forearm was placed in full pronation.
12. What is the major pitfall of this type?
The failure to fully evaluate the fracture and determine that it is truly not significantly displaced.
13. What are the two major deformities seen with Type I injuries?
1. Medial greenstick collapse. This is due to the relative weakness of the medial column, which allows it to collapse in a varus direction. This can be especially a problem if the patient does not normally have any significant carrying angle. It may require closed reduction and pin fixation (DE95).
2. Often the condyles are hyperextended or extended which, clinically, can accentuate the unattractiveness of the varus deformity.
14. How can one avoid these complications?
By examining the patient (DE95) with a lot of care and coaxing, the elbow can often be brought out into almost full extension. If it is a true Type I lesion, the carrying angle can be evaluated clinically. It is a little bit difficult to determine the clinical alignment in the saggital plane i.e. the ability to flex and extend the elbow or the presence of hyperextension, because of the acute swelling.
Type II Fractures
15. What are the criteria for Type II Fractures?
This is an incomplete fracture in which there is usually some posterior cortical integrity remaining. The integrity must be sufficient to prevent rotation of the distal fragment when the elbow is hyper flexed.
16. How are Type II Fractures best treated?
They must be reduced and then stabilized.
17. What is the manipulative process?
One needs to first correct any coronal malalignment. This is usually done with the forearm pronated.
The saggital alignment is then corrected by reestablishing flexion. Hyper flexing the elbow usually does this. In doing so, one usually meets some resistance prior to obtaining full hyperflexion, which is the angle at which the elbow joint reaches its maximum excursion with the distal fragment still in the uncorrected extended position. At this point the elbow is then forced into maximum flexion. This should correct the angular deformity of the distal humerus in the saggital plane.
Following correction of the deformity of the saggital plane, the elbow should be brought out into full extension and examined both clinically and radiographically to make sure that the carrying angle has been corrected.
18. Post reduction, how is the reduction maintained?
The criterion for a Type II fracture is the ability to be stabilized with a long arm cast.
Determining the ability to treat these fractures with a cast alone involves testing its’ stability to rotation with the elbow flexed at 120 degrees. The shoulder is fully externally rotated and x-rays are taken to make sure that the reduction has been maintained with the elbow flexed only to 120 degrees. If it stays stable in this position then there is enough internal stability at the fracture site that it can be managed with a cast alone barring severe swelling or vascular compromise.
Warning! Flexing to greater than 120 degrees increases the risk of vascular problems. (MI84)
19. If the reduction is stable at 120 degrees of flexion how must the cast be applied post reduction?
However, stabilization in a cast or splint at 90 degrees is usually not adequate. The elbow must be flexed at least 120 degrees. Allowing the elbow to be flexed to only 90 degrees may result in loss of correction of the shaft-condylar angle.
They are best-immobilized post reduction with a Figure-of-8 cast as recommended originally by Rang(RA).It is always important to incorporate thesling into the cast so that the elbow extension can be maintained. Failure to do so will allow the cast to slip into some extension and can result in loss of the reduction.
If in Type II Fractures there is any concern with vascular compromise or fracture stability, then it is best to treat this as one would treat a Type III Fracture, that is one in which the fragments are completely displaced.
Type III Fractures
20. How are extension Type III supracondylar fractures sub classified?
They are classified into two major groups: posteromedial and posterolateral. The posterolateral pattern consists of only about 25% of the fractures.
21. Does this sub classification make a difference?
Yes.
22. In what aspects does the sub classification affect the management of Type III supracondylar extension fractures?
- It can determine the major nerve or vessel injury.
- It can determine the surgical approach if an open reduction is necessary.
- It also can determine the risk of later complications (CA95).
23. What Type has a greater potential for complications?
One must have more respect for the posterolateral fractures because the distal fragment will often be impinging upon the brachial artery and medial nerve (CA95).
24.What is the major concern with the posterolateral fractures?
They have a higher risk of:
- vascular injuries;
- irreducibility.
25. What is the major concern with posteromedial fractures?
The radial nerve is more vulnerable to injury.
26. How are Type III Fractures best treated?
Simple. One must first obtain reduction and then maintain the reduction.
There is no true emergency to treat these fractures in the middle of the night. Two studies have demonstrated that waiting more than 8 hours to reduce and stabilize these fractures did not increase the incidence of complications or unsatisfactory results (LE02A,ME01).
27. What does the manipulative process entail?
It consists of three steps:
1. The alignment needs to be corrected. With the elbow in extension, you align the distal fragment to the proximal fragment.
2. Re-establish length. This often requires someone to apply counter traction as the surgeon applies traction to re-establish length.
2. The angulation and posterior displacement of the distal fragment needs to be corrected.
Sometimes the distal fragment needs to be a little bit hyperextended. Care must be taken to avoid injury to the neurovascular structures when this occurs. Traction is applied to the forearm with the elbow in semi-flexion and at the same time pressure is applied to the anterior portion of the distal fragment to push it posteriorly. This facilitates the reduction of the distal fragment to the proximal fragment. Sometimes the distal portion of the proximal fragment is impaled through the biceps and the brachialis may need to be milked off the fragment (AR97).
Once the fragments are reduced, the elbow is then hyperflexed and hyperpronated.
Then, with the elbow fully flexed the reduction is checked with the shoulder fully, externally rotated.
28. How does one maintain the reduction once obtained?
The use of a Figure-of-Eight cast is no longer acceptable in maintaining the reduction of Type III fractures. To hold the distal fragment stable so that it does not displace with rotation requires full flexion of the elbow. This carries a significant risk for vascular compromise.
29. Since a cast is inadequate for maintaining the reduction
of type III fractures, what is the best way to maintain the reduction?
The standard now for maintaining the reduction is percutaneous pin fixation(BO92).
30. In what manner may the pins be used?
Medial lateral pins.
31. What are the advantages of the medial-lateral pin construct?
-It is the most stable construct of all the pin placement patterns for rotational stability. (LE02,ZI94)
-It allows the angle to be extended once the pins are inserted so that the maintenance of the carrying angle can be assessed.
32.What are the disadvantages of the medial-lateral construct?
The primary disadvantage is the possibility of ulnar nerve injury.
33.How can the danger of ulnar nerve injury be minimized?
The ulnar nerve can be protected by making an incision directly over the medial epicondyle and visualizing the ulnar nerve or epicondyle directly so that the location of the pin is exactly in the center of the epicondyle.
Another technique is to localize the position of the ulnar nerve with a nerve stimulator(WI02).
34. What are the principles of lateral pin fixation?
This usually involves two lateral pins which are placed parallel or divergent.
The advantages being that that are easy to apply and there is almost no risk of nerve injury.
The disadvantage is that there is poor rotational stability. Again, the pins must be parallel or divergent.
Pins crossing at the fracture site are an unstable construct and may not hold the reduction.
However, loss of rotation of the distal fragment, if the coronal alignment is maintained is usually of little or no clinical significance. The elbow function and clinical appearance is the same as those who have not developed a rotation(GR01,LE02,SK01).
35. How can the rotational stability with two lateral pins be enhanced?
Adding a third lateral pin. This third lateral pin usually goes very obliquely up to the diaphysis and may even almost be intramedullary. It seems to enhance rotational stability almost equal to that of medial-lateral pins (ZI94).
36. What are the advantages and disadvantages of the three-lateral pin construct?
Advantages – In studies by Zionts (ZI94) and associates, this construct is almost as strong as medial-lateral pins
Disadvantages – In larger patients there may still be some rotational instability. Even with three lateral pins, there may be a need to supplement with a medial pin.
37. Following pin fixation how are these Type III Fractures managed?
Usually all that is necessary is immobilization in cast or splint at 90 degrees or less for about three weeks.
38. What does the pucker sign indicate?
It indicates that the distal spike of the proximal fragment is impaled in the subcutaneous tissues and possibly button-holed through the brachialis muscle which may make the fracture irreducible. This impaled muscle may be released by the “milking maneuver” in which the brachialis muscle is milked distallyoff the spike of the proximal fragment(AR97).
39. In those irreducible fractures, what are the preferred surgical approaches?
Posterior lateral fractures: The appropriate approach to a posterior lateral fracture is an anterior medial approach which allows visualization of the median nerve and brachial artery both which are usually tented across the distal spike of the proximal fragment. This allows direct visualization of these anterior interposed neurovascular tissues. This is usually done through an anteromedial incision.
Posterior medial fractures can be approached through an anterolateral incision to allow direct visualization of the radial nerve as it is usually tented over the distal fragment.
40. What about the posterior approach?
Overall, this is probably the most widely used surgical approach. It usually involves a posterior triceps splitting approach(SC02,SR00).
The advantages are: it is an easier approach and it allows direct visualization of the fracture site.
The disadvantages are: it injures virgin tissue and one is unable to visualize the anterior nerves and arteries that are usually interposed in irreducible fractures.
41. What is the primary purpose of an open reduction?
The philosophy is to:
-remove the interposed structures;
-then facilitate a closed reduction; and
-perform a percutaneous pin fixation.
The main interposed structure is a flap of periosteum that tears proximally but remains attached to the distal fragment. This flap of periosteum serves as a guide to bringing the distal fragment forward to reduce it(AB82).
Other interposed structures include brachialis muscle and on occasion the neurovascular structures.
There does not appear to be any risks regarding the final outcome or rate of complications in performing an open reduction on irreducible Type III fractures. It is now a widely accepted procedure(CR92,FL98,KE01,RE01).
42.What about late appearing fractures?
If the fragments are in apposition to each other and there is already periosteal new bone formation, it is often best to wait as the remodeling process may provide surprising results.
43.What about those late appearing fractures that do not fully remodel?
Again, once periosteal bone formation has begun it may be best to wait and see how much remodeling occurs and, if need be, a corrective osteotomy be done when the patient has regained full motion and muscle strength.
44.What are the risks of doing a late open reduction?
Myositis ossificans. Thus when faced with a late appearing fracture one is faced with the dilemma of doing a delayed open reduction and risking myositis ossificans which can produce significant loss of motion (LA91). Or, wait and do a corrective osteotomy when the patient has regained recovered full motion.
45.In addition to evaluating the neurovascular status, what else needs to be done in assessing Type III supracondylar fractures?
Always check for ipsilateral fractures.
46.Ipsilateral fractures, how do they need to be stabilized?
Both the supracondylar and radius and ulna fractures need to be stabilized with pins(RO01,SI02).
In those with ipsilateral distal radial fractures, usually the supracondylar fracture needs to be reduced and stabilized with percutaneous pins first.
In those with ipsilateral shaft fractures one has to first establish intramedullary pin fixation so that this can be used to effect a reduction of the supracondylar fracture which also needs to be stabilized with percutaneous pins.
47. How do flexion-type supracondylar fractures present?
In the same manner as extension-type fractures:
Type I – undisplaced, no reduction needed;
Type II - enough intrinsic stability to be treated with a cast alone; and
Type III – no intrinsic stability, needs surgical stabilization.