Clinical diagnosis of clavicle fractures: a pilot study

EM Advances

CJEM 2001;3(2):95-98

Abstract

Résumé

Introduction

The clavicle is the most commonly fractured bone in children, and clavicle fractures account for up to 40% of shoulder girdle injuries seen in the emergency department (ED).¹ Because the bone is subcutaneous along its entire length, it is easily accessible to both inspection and palpation. Consequently, clavicle fractures and their management have been described as far back as ancient Greece and Hippocrates.²

The Allman classification divides clavicle fractures by location.³ Group I fractures involve the middle third, Group II, the lateral third and Group III, the medial third. These zones account for approximately 80%, 15% and 5% of clavicle fractures, respectively. The Neer classification further subdivides Group II fractures based on associated ligamentous disruption.⁴ The S-shape of the clavicle and its regional porosity variations give it flexural and torsional properties that make it weakest in its middle portion. In addition, strong ligamentous and muscular attachments medially and laterally leave the relatively free middle third more susceptible to fracture when it is stressed. Therefore, most fractures occur in the middle third.

It is standard ED practice to obtain radiographs when evaluating clavicular injuries. Radiographs confirm the presence and location of fractures, but whether it is necessary to x-ray all clavicle fractures has yet to be determined. When considering the need for any diagnostic test, it is important to ask whether the same information is available clinically, and whether the test (i.e., radiograph) will lead to a change in patient management or outcome.

Clavicle fractures in general, and middle third fractures in particular, have excellent outcomes with conservative management.¹ Complications from clavicle fractures are rare and are generally restricted to fractures in the medial or lateral aspects of the bone. Therefore, it would seem that if physicians can accurately identify middle third fractures clinically, then x-rays may be unnecessary. Omitting radiographs in the diagnostic work-up of these patients could shorten ED length of stay, reduce diagnostic costs and limit exposure to ionizing radiation.

The objective of this study was to determine whether ED physicians can accurately predict, on clinical examination, both the presence and location of clavicle fractures prior to obtaining radiographs. Our hope is that this pilot study could pave the way for a formal prospective analysis of the utility of clavicle radiography.

Methods

Design

A prospective study of ED patients who had injuries compatible with a clavicle fracture, seen during the 16-month study period.

Setting and participants

The study was carried out at 2 urban teaching hospitals with a combined census of 85,000 ED patient visits per annum. One of the hospitals is a regional Level 1 trauma centre, and both are staffed by full-time emergency physicians. Participating physicians were either FRCP(C) or CCFP-EM qualified, or were senior emergency medicine (EM) residents.

Intervention

Participating physicians were encouraged not to alter their clinical practice for this study, and no extra training was provided except for a 1-hour didactic session discussing the diagnosis, complications and management of clavicle fractures. After examining patients and prior to obtaining radiographs, ED physicians completed a data form that asked them to predict the presence or absence of a fracture. In cases where a fracture was predicted, physicians were asked to specify the fracture location based on the following choices: medial third, middle third, lateral third, or "unsure." Clinical predictions were subsequently compared to radiology reports, which were considered to be the diagnostic reference standard. Patients were excluded if the data form was not completed or if the x-ray was performed prior to completion of the data form. Multiple trauma victims were also excluded, and multiple trauma was defined as a significant injury involving a second (non-musculoskeletal) organ system.

Analysis

Descriptive statistics, including proportions and means, were determined using standard formulae. Intervals of 95% confidence were calculated to show the precision of critical values, and contingency tables were constructed to illustrate the level of agreement between clinical predictions and radiographic findings. The study received ethics approval from the Queen's University Research Ethics Board.

Results

Between April 1999 and August 2000, 184 patients with injuries consistent with clavicle fracture were seen. Of these, 106 (58%) were enrolled and 78 excluded -- 70 because of recruitment failure, 7 because of multiple trauma and one who had an x-ray done prior to data form completion. Table 1 shows that clinical characteristics were similar for patients enrolled and excluded.

Ninety-four of 106 enrolled patients (89%) had an acute clavicle fracture, and all 94 of these were predicted on clinical grounds prior to x-ray (Table 2). In 6 cases, physicians predicted a fracture when the radiograph was negative and in 6 additional cases, physicians were clinically unsure and the radiograph was negative. In the latter group, 3 patients had nonspecific soft tissue injuries, 2 had acromioclavicular separations and 1 had a glenohumeral dislocation.

Seventy-five clavicle fractures (80%) were middle third, 15 (16%) were lateral third, 2 (2%) were medial third and 2 (2%) involved both middle and lateral thirds (Table 3). Physicians correctly predicted fracture location in 83 of 94 patients (89%; 95% confidence interval [CI], 82%-95%). In the 64 cases where physicians predicted a middle third fracture, they were 100% accurate (95% CI, 95%-100%). The 11 incorrect predictions were "conservative" errors, with the physician predicting the fracture to be lateral (8 times) or unsure (3 times) when it was actually middle third. In the 15 cases of lateral third fracture and the 2 cases of medial third fracture, the physicians' predictions were correct all 17 times. Two fractures involved both middle and lateral thirds. Physicians predicted both of these to be lateral. In this series of 172 consecutive ED patients with acute clavicle fracture, no cases of pneumothorax or neurovascular injury were identified during the ED visit.

Discussion

Clavicle fractures are common. Most involve the middle third, the diagnosis is usually clinically obvious, and they are managed conservatively with a sling or shoulder immobilizer for support.

Functional outcomes are very good and complications are rare.¹ The least invasive management option, simple support, has outcomes at least as good as more invasive surgical options, even if there are multiple fracture fragments.⁵ In fact, some authors feel that comminuted fractures unite more quickly and strongly because there is more callus to enhance bone healing.⁶

Morbidity associated with clavicle fractures may be related to associated injuries or delayed complications. Associated injuries include other orthopedic trauma, pneumothorax, brachial plexus disruption or major vascular injury.¹ Delayed complications include fracture mal-union, non-union and shoulder arthritis.¹ But while pneumothorax and neurovascular injuries are frequently discussed, they are, in fact, very rare. In a series of 690 clavicle fractures, Rowe⁷ reported a 3% incidence of pneumothorax, and in our series of 172 consecutive fractures, we identified no cases. This suggests that clavicle fractures should not provoke physicians to perform chest radiography unless the history and physical exam raise a suspicion of pneumothorax or blunt chest injury.

Neurovascular injuries are even more uncommon.¹ Since the neurovascular bundle is protected under the thick, medial portion of the clavicle, it takes considerable trauma to injure these structures.⁸

Non-union and arthritis are largely associated with Group II (lateral) fractures, which account for only 15% of clavicle fractures⁹ but are responsible for half of all non-unions. Delayed arthritis is most likely in patients who suffer lateral fractures with ligamentous (acromioclavicular and coraco-clavicular) disruption. However, while delayed complications are more likely with lateral fractures, the majority of such injuries do well. Nordqvist followed 110 patients with lateral clavicle fractures, all managed with simple sling support.¹⁰ At 15-year follow-up, only 5% complained of mild pain with range of motion and none had any disability.

Clavicle radiographs are performed to confirm the diagnosis and location of fractures. Because outcomes may be worse with medial third or lateral third injuries, it may be important to localize these accurately in the ED. Consequently, we attempted to determine whether emergency physicians can make the diagnosis of a fracture clinically and whether they incorrectly diagnose medial or lateral third injuries as middle third. Our data show that ED physicians can clinically predict the presence and location of clavicle fractures with a high degree of accuracy. The data also show that, in every case where the physician's clinical prediction differed from the radiographic diagnosis, the clinical impression was conservative (i.e., overestimated the potential injury severity).

Limitations and future research

Approximately 40% of the patients who presented with clavicle fractures during the study period were not enrolled. So, although there are no apparent differences between enrolled and non-enrolled patients, it is possible that there is an unidentified selection bias. Further, the physicians in this study were full time ED physicians and dedicated EM residents; therefore, these findings may not be generalizeable to all physicians in all centres. In addition, our sample size was limited; we enrolled a relatively small number of patients with medial and lateral clavicular fractures. If we had enrolled a larger number of patients with these less common injuries, our physicians might have incorrectly identified some of the injuries as middle third injuries. Finally, it is conceivable that patients with subtle clavicle fractures were seen at our centre and missed because the clinical suspicion was so low as to not perform an x-ray. If this occurred, it would falsely increase the apparent sensitivity of clinical examination.

This study paves the way for future prospective studies to clarify the indications for diagnostic radiography in patients with suspected clavicle fractures.

Conclusions

This pilot study suggests that ED physicians can clinically predict the presence and location of clavicle fractures with a high degree of accuracy. It may be that x-rays are not always necessary in patients suspected of having a clavicle fracture. Future studies should define the indications for diagnostic radiography in patients with suspected clavicle fractures.

References

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2. Adams CF. The genuine works of Hippocrates. Baltimore: Williams & Wilkins; 1939.
3. Allman FC. Fractures and ligamentous injuries of the clavicle and its articulation. J Bone Joint Surg [Am] 1967;49:774-84.
4. Neer CS. Fracture of the distal clavicle with detachment of coracoclavicular ligaments in adults. J Trauma 1963;3:99-110.
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9. Neer CS. Non-union of the clavicle. JAMA 1960;172:1006-11.
10. Nordqvist A, Petersson C, Redlund-Johnell I.The natural course of lateral clavicle fracture. 15 (11-21) year follow-up of 110 cases. Acta Orthop Scand 1993;64(1):87-91.