Simultaneous bilateral Mason type IIb radial head fractures in a young female: Was an increased carrying angle the cause?

Introduction

Bilateral radial head fractures are a rare entity; of which the incidence of simultaneous bilateral fractures is <1%.^[1] Elbow biomechanics plays a vital role in the nature of the injury.^[2] Treatment options are largely dependent on the fracture type, with nonoperative treatment recommended for Mason type I and operative treatment recommended for Mason type II–IV radial head fractures.^[1] We discuss a case of simultaneous bilateral type IIb radial head fractures treated successfully without surgery.

Case Report

A 47-year-old right-handed lady presented to our clinic with a 3 weeks history of fall on outstretched hands while on vacation abroad. She tripped over a small wall and fell, supporting herself on both palms. Initially, she had pain in both elbows with limited range of movement. Radiographs revealed that she had sustained bilateral radial head fractures. She was placed in above elbow back slabs while abroad.

On clinical examination at our clinic 3 weeks later this patient had minimal tenderness on palpation over the radial head area. There was no swelling appreciated. Her movements were terminally painful, but the intensity of pain was less. She was advised to mobilize within her limits of pain, and bilateral slings were given for comfort. It was evident radiologically that she had sustained bilateral Mason type IIb radial head fractures [Figures 1 and 2].

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Figure 1

Initial radiograph of left elbow

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Figure 2

Initial radiograph of right elbow

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At a 6 weeks follow-up, she was much more comfortable, and it was decided to commence mobilisation under the guidance of a physiotherapist.

This patient was regularly reviewed at 3, 6, 9 months, and 1-year. On final follow-up 2 years later her radiographs revealed that the fractures had completely healed [Figures 3 and 4], and she had a painless range of movement [Figures 5-7].

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Figure 3

Final radiograph of left elbow

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Figure 4

Final radiograph of right elbow

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Figure 5

Clinical photograph – neutral position

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Figure 6

Clinical photograph – supination

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Figure 7

Clinical photograph – pronation

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Discussion

Radial head fracture is the most common type of elbow fracture in adults and results from a fall on an outstretched hand.^[3,4] The position of the forearm and flexion at the elbow during actual impact play a significant role in the load transfer occurring at the radiocapitellar joint. Maximum forces at the radiocapitellar joint are observed in a pronated forearm with a flexion of <30° at the elbow joint.^[5] Varus and valgus angulations at the elbow also play an equally vital role, with almost 97% of patients having a load transmission occurring at the radiocapitellar joint in the valgus position.^[6,7]

Radial head fractures were originally classified by Mason into four types based primarily on the displacement of the fracture fragments.^[8] This classification was further modified by Johnston wherein the Essex-Lopresti injury was considered [Table 1].^[9] The radial head is susceptible for a fracture because of an angulation of about 15° between the radial neck and shaft.^[4,10,11] The frequency of radial head fractures is reported to be around 1% of all fractures.^[12] A recent study has specifically reported the incidence of simultaneous bilateral fractures to be <1%.^[1]

Table 1 Modified Mason classification

Kovar et al., recommended that all patients with type II–IV radial head fractures should undergo operative fixation for a better outcome. Similarly Kutscha-Lissberg et al. recommended operative fixation for fractures of type IIb and higher.^[12] However, a noteworthy point is that Kutscha-Lissberg et al. had only one patient with simultaneous bilateral Mason type IIb injury in their study population.

Our patient had simultaneous bilateral Mason type IIb radial head fractures, which is extremely rare. The senior author is of the opinion that an increased carrying angle in this female patient of 18°could well have caused something like the “nutcracker effect” leading to these fractures. In a classic case of “nutcracker effect,” the medial portion of the radial head is compressed between the capitulum and the radial shaft and lateral part of the radial head.^[13] Our patient, however, had bilateral radial head fractures with a minimal lateral displacement of the radial head fragment, hence though not exactly identical, but the mechanism could be similar to that of the “nutcracker” effect. In our opinion, an increased valgus angulation at the elbow and classical position of forearms in pronation during impact compounded the loading forces at the elbow joint resulting in simultaneous bilateral fractures.

Conclusion

Although operative treatment is recommended for Mason type II fractures, we firmly believe that each case is unique and must be treated on its individual merit. A detailed history, specifically of the attitude of the extremity on initial impact and individual anatomic variations should also be considered. The excellent outcome noted in this particular case of late presentation justifies our approach of treating this injury without any operative intervention.