Bipolar clavicular fractures and treatment options

Introduction Fractures of the clavicle are common injuries, accounting 2.6–4% of all fractures in adults. Of these fractures, 21–28% are lateral clavicle fractures and 2–3% are medial clavicle fractures. Bipolar clavicle fractures are defined as a lateral and medial fracture and are uncommon. There is no consensus on the treatment of these fractures. The aim of this study is to provide a treatment on bipolar clavicle fractures based on the current literature. Methods The electronic databases PubMed, the Cochrane library and EMBASE were searched up on September 25th, 2017. Two reviewers (KR and TG) independently screened titles and abstracts for their relevance. Studies designed to evaluate the outcomes of conservative and/or operative treatment of segmental bipolar clavicle fractures in adults (> 16 years) were included. Editorials and commentaries were excluded, as well as synthetic, cadaveric and animal studies. Primary outcomes considered were pain reduction and shoulder function. Secondary outcomes considered are complications. Results Ten studies reporting results from ten patients were included for the review. In most patients, if treated operatively, surgical treatment with the use of double plating was performed. Only in elderly patients conservative treatment was adopted. All included patients were pain free and had a full range of motion after 3–6 months. Only two case reports provided a DASH score, while in eight studies no functional outcome score was measured. Conclusion A missed bipolar fracture can complicate the clinical progress. Surgical management of these fractures may be necessary; however, the treatment of choice depends on the age of the patient, daily activities and comorbidity. Electronic supplementary material The online version of this article (10.1007/s00068-019-01191-5) contains supplementary material, which is available to authorized users.


Case description
A 23-year-old man was admitted after a high speed motor vehicle accident. A total body computed tomography was performed at the emergency department and showed the following injuries: cervical 4-6 fractures with spinal cord injury, left vertebral artery dissection, left transverse process fractures thoracic 5-8, fractures of ribs 1 and 2 on the left side, bilateral contusions of the lung and a bipolar clavicle fracture on the left side. The patient was admitted to our institution for an ASIA C type injury following local spinal injury protocol. The patient remained hemodynamically stable, but became symptomatic for pain of the left clavicle with a median NRS of 5 during the admission, measured three times a day.
Additional X-rays showed a medial clavicle fracture with 15 mm displacement and a lateral fracture with 10 mm displacement (IMAGE 1 in Supplementary material). Fracture fixation was performed by double plating after fracture reduction, utilizing a Depuy Synthes 2.7-3.5 mm Variable

Literature review
The electronic databases PubMed, the Cochrane library and EMBASE were searched up on September 25th, 2017. The search was performed with both keywords and MeSH terms. The search consisted of: bipolar OR segmental AND clavicle. Two reviewers (KR and TG) independently screened titles and abstracts for their relevance. Additionally, the reference lists of all included articles were additionally searched for other relevant references. Studies designed to evaluate the outcomes of conservative and/or operative treatment of segmental bipolar clavicle fractures in adults (> 16 years) were included. Editorials and commentaries were excluded, as well as synthetic, cadaveric and animal studies. Inclusion was not otherwise restricted by study size, language or publication type.
Primary outcomes considered were pain reduction and shoulder function. Secondary outcomes considered are complications, such as infection, non-union and implant failure. None of the ten case reports described how pain, shoulder function and complications were scored. Only two case reports provided a DASH score.

Results
Details of the literature search are shown in Fig. 1. All ten included studies are single case reports. Characteristics of the studies are shown in Table 1. Three elderly patients were treated conservatively and seven patients were treated operatively. In most of these operatively treated patients double plate fixation was performed. In two cases clinical impairment was seen. The medial clavicle fracture was missed directly after the injury. In the first case the medial fracture was found after 4 days and before surgery, so no extra operation was needed. In the second case the medial fracture was found after 28 days. An extra operation was performed. In all cases the fractures healed and in one case the operation was complicated by a pneumothorax [8]. In three cases implant removal was performed.

Discussion
This study describes the treatment of a patient with a bipolar clavicle fracture and presents a review of the current literature regarding bipolar clavicle fractures. Only ten single case reports could be included in the review, describing varying treatment modalities. In most patients, surgical treatment with the use of double plating was performed. Only in elderly patients conservative treatment was adopted. All included patients were pain free and had a full range of motion after 3-6 months. Furthermore only 2 of the 10 available case reports described a validated functional outcome score.
Most of the bipolar fractures are sustained by high energy trauma. Of all clavicle fractures 21-28% are lateral fractures and 2-3% are medial fractures [1]. A truly bipolar clavicle fracture is a rare entity. The term ''floating clavicle'' refers to an AC-and SC-displacement without fractures [13,14]. A bipolar fracture can easily be missed and may therefore complicate the clinical progress. It is advised to assess the whole length of the clavicle clinically and radiologically  when fractured, in order not to miss a bipolar fracture. When there is any doubt, the use of a computed tomography scan is recommended.
Research has shown that a non-operative treatment of an isolated, non-displaced, medial clavicle produced limited pain and excellent functional outcomes [2]. Displaced medial fracture require operative treatment [15].
Lateral fractures require operative management if displaced [16]. Two studies in this review used a hook plate for fixation of the lateral fracture. One article has shown that locking plate fixation is superior compared to hook plate fixation in lateral clavicle fractures [17].
This study presents a complete overview of the current literature. Due to the rarity of this injury, a formal metaanalysis of the literature was not possible.
These injuries may impair clinical progress if undetected, as seen in two cases in our review. We suggest that operative treatment should be performed for displaced medial and lateral fractures in a bipolar fracture, although the treatment of choice depends on the age of the patient, daily activities and comorbidity. While displaced fractures may benefit from surgery, treating only one part of a bipolar clavicle fracture may complicate treatment should the other part become displaced at a later instance.

Conclusion
Based on the current evidence, no strong recommendation can be made on the treatment of bipolar clavicle fractures. Literature has shown that operative treatment should be performed in isolated medial an lateral clavicle fractures. We suggest that displaced bipolar clavicle fractures should be treated operatively. However the treatment of a bipolar clavicle fracture depends on the age of the patient, daily activities and comorbidity.
Funding No funding was received.

Compliance with ethical standards
The treatments described in the manuscript were performed in accordance with the ethical standards of our institute and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Conflict of interest
The authors, their immediate family, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
Ethical approval Not applicable, experimental procedures involving human participants were not performed.

Informed consent Informed consent was obtained.
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