CASE                                3                               

It is a busy night in the emergency room—you have just been consulted on two patients with “elbow fractures.” The first one is a 5-year-old girl who was climbing on a playground structure and fell off. She has pain in her left elbow and is refusing to move the arm normally. She is neurovascularly intact on examination.

What is the next imaging study you should order if the AP and lateral films show the following (Fig. 10–3A and B)?

1. Comparison views of the other elbow

2. Internal oblique view of the elbow

3. External oblique view of the elbow

4. CT scan of the elbow

5. MRI of the elbow

Figure 10–3 A–B

Discussion

The correct answer is (B). This is a lateral condyle fracture. The internal oblique view is imperative because the fracture fragment often lies posterolateral, and the amount of displacement can be missed on just an AP and lateral x-ray. The internal oblique view is obtained to better evaluate the fracture pattern and the amount of displacement. Comparison views of the other elbow are rarely indicated if you know your pediatric elbow anatomy and would not be helpful in this case—you already know what the fracture is, but you need to know how much displacement there is. The external oblique view is helpful for evaluation of the medial epicondyle and condyle, not the lateral condyle. A CT scan of the elbow would have certainly given you a lot of data, but the single internal oblique view would likely give you sufficient information and avoid a larger radiation dose to the child that would come with the CT scan. An MRI would also provide a lot of data but not the necessary next step—an MRI at this age would likely require general anesthesia.

An internal oblique view is obtained for the patient above. It shows less than 2 mm of displacement. What is your recommended treatment?

1. Application of long-arm splint or cast with follow-up in 5 to 7 days

2. Application of long-arm cast with follow-up in 3 weeks

3. Application of a Munster cast with follow-up in 3 to 5 days

4. Application of a Munster cast with follow-up in 3 weeks

5. Application of a long-arm cast with follow-up in 5 to 6 weeks

Discussion

The correct answer is (A). The child has a type I lateral condyle fracture. A long-arm splint is preferred by some to allow for easy removal at time of follow-up in order to get clearer x-rays rather than having to remove a whole cast. The internal oblique view is most sensitive for evaluating displacement, and for this patient, the displacement is less than 2 mm which is acceptable. Since surgery is not indicated at this time, the appropriate treatment is in a cast—in order to effectively immobilize the arm to stabilize the lateral condyle, a long-arm cast is necessary; a Munster cast is not appropriate for a fracture of the humerus. Choices C and D are therefore incorrect. Because lateral condyle fractures, even non- and minimally displaced ones, are known to displace in the first several days of immobilization, close follow-up is imperative as up to 10% will displace enough to need surgical reduction and stabilization. Therefore, choices B (3-week follow-up) and E (5–6 weeks) follow-up are too long to catch those that displace.

In the room next door, there is a 6-year-old girl who also fell from a playground structure and has the following injury (Fig. 10–4A and B):

Figure 10–4 A–B

What is the appropriate treatment for this fracture?

1. Application of long-arm cast, immobilization for 4 weeks

2. Closed reduction in the ER and immobilization in long-arm cast for 6 weeks

3. Open reduction and percutaneous pinning

4. Open reduction and internal fixation with a screw and washer

5. Open reduction and internal fixation with plate and screws

Discussion

The correct answer is (C). This is a displaced lateral condyle fracture and needs surgical reduction and stabilization—therefore A and B are incorrect. Lateral condyle fractures can be closed reduced and pinned in the OR. An arthrogram is then performed, and if the intra-articular fracture is anatomically reduced and there is no articular step-off, then an open procedure does not need to be performed. Many surgeons will by-pass attempted closed reduction for notably displaced fractures and go straight to open reduction (note that the attempted closed reduction was not an option in this question due to this being a surgeon preference issue). If you are going to do an open reduction, then use stabilization with smooth k-wires as your first choice. If the patient is older or the fracture cannot be stabilized with pins, then some surgeons would use a screw. This is not usually the first choice however. For a 6-year old with a straightforward lateral condyle fracture, plates and screws are not necessary. When making the surgical approach to the lateral condyle, you want to avoid dissecting posteriorly to help mobilize the fragment.

What is the most concerning potential risk of posterior dissection?

1. Damage to cartilage due to rotation of the fragment

2. Osteonecrosis due to loss of blood supply

3. No increased risk with posterior dissection

4. Delayed healing

Discussion

The correct answer is (B). A Kocher approach is used to perform an open reduction of a lateral condyle fracture. During the approach and reduction of the fracture, the surgeon should avoid posterior dissection in order to avoid disrupting the blood supply of the lateral condyle fragment—the blood supply comes in posteriorly. If you were to dissect posteriorly, you could injure the blood supply and cause osteonecrosis. AVN of the lateral condyle is the main reason to avoid posterior dissection.

Objectives: Did you learn...?

Correct radiographic evaluation of a lateral condyle fracture?

Treatment of nondisplaced and displaced lateral humeral condyle fractures? Risk of displacement in type 1 fractures?

Safe approach to the lateral condyle, importance of avoiding posterior dissection?