Introduction
Clavicle fractures are common, and perhaps thus not particularly interesting.
Two points demand your attention. First, it has long been thought that malunion (or even non-union) of clavicle fractures was well tolerated and imposed little morbidity. For that reason, it was likewise thought that these fractures could be treated with almost benign neglect. Current investigation is revisiting that assumption and may herald a shift in treatment paradigms.
Second, clavicle fractures in the pediatric population differ from the adult form in terms of etiology, treatment requirements and prognosis. In all ways, they represent a distinct category on injury. And further note that the clavicular physis is the last to close -perhaps as late as age 21 
making the category of 'pediatric' fractures broader than one might otherwise imagine.
Anatomy
The clavicle is an S shaped bone attaching medially to the sternum at the sternoclavicular joint, and laterally to the coracoid and the acromion. The coracoclavicular ligaments, namely, the trapezoid and coronoid, attach from the coracoid process to the inferior aspect of the clavicle and help suspend the arm. The acromioclavicular ligaments resist anterior/posterior displacement of the distal clavicle relative to the acromion. The clavicle overlies the brachial plexus, as well as the jugular and subclavian blood vessels.
The pectoralis major and deltoid originate from the clavicle and the trapezius inserts on it. The deforming forces these muscles can produce on clavicular fracture must be considered.
Classification
Clavicle fractures are classified by location. The regions of the clavicle are segmented into thirds: medial (aka proximal), middle and lateral (distal). Mid shaft clavicular fractures represent an overwhelming majority of these injuries (80%). Among the distal clavicular fractures (near the AC joint) the fractures are further classified (following Neer) in terms of the location of the clavicle fracture relative to the coracoclavicular ligaments. These fractures are designated as medial to the coracoclavicular ligaments; between the two coracoclavicular ligaments (ie, the intact trapezoid remains attached to the distal/lateral segment); or lateral to coracoclavicular ligament, within the acromioclavicular joint itself.
(Author's note: I have seen the 2nd Neer group - fracture at the level of coracoclavicular ligaments divided into 2 sub-groups, ie. between the two ligaments and medial to both of the ligaments. Perhaps owing my own obtuseness, I don't understand that. In the so-called Neer "IIA Fracture" the fracture is medial to the ligaments, ie the conoid and trapezoid ligaments remain intact and attached to the distal fragment. To me, that is simply a type I fracture -"medial to the coracoclavicular ligaments" but one that just happens to lie at the extreme lateral position. In other words, a type IIA fracture is really a type I fracture that the given observer deems 'too far lateral to be a type I', even though no exact anatomic border is crossed. If I read this correctly, this is precisely the type of fracture classification that should be avoided. I look forward to revision of my comments clarifying this.)
Allman classification scheme with the Neer modification is the most commonly used and is listed in detail below.
- Group I - Fracture of middle third (80%)
- Group II - Fracture of the distal third (15%)
- Type I - Minimally displaced/interligamentous
- Type II - Displaced due to fracture medial to the coracoclavicular ligaments
- IIA - Both the conoid and trapezoid remain attached to distal fragment
- IIB - Either the conoid is torn or both the conoid and trapezoid are torn
- Type III - Fractures involving articular surface
- Type IV - Ligaments intact to the periosteum with displacement of the proximal fragment
- Type V - Comminuted
- Group III - Fracture of the proximal third (5%)
- Type I - Minimal displacement
- Type II - Displaced
- Type III - Intraarticular
- Type IV - Epiphyseal separation (observed in patients aged 25 y and younger)
Presentation
Patients present with shoulder pain and deformity typically after a fall on an outstretched arm. There is usually tenderness with visible deformity. There may be crepitus. There may be tenting of the skin. A detailed neurological examination has to be performed to rule out an associated injury.
Diagnosis
The diagnosis of a clavicle fracture is usually obvious if it is mid shaft. Closer scrutiny may be necessary for proximal and distal clavicular fractures. In the case of distal clavicular fractures, attention must be directed to the precise fracture anatomy (see classification, above). A chest x-ray should be performed to rule out a pneumothorax. The clavicle is best viewed with 2 views - an AP view & a view with the beam angled 30 degrees cephalad. The open/closed status of the fracture should be obvious; what is not obvious, perhaps, is that a closed fracture with tented skin may lead to skin necrosis and become an open fracture in short order.
Treatment
Traditionally mid shaft clavicular fractures were treated with simple immobilization. Greater attention has been given now to the possibility of non-unions and malunions, and surgical fixation is offered as the primary treatment. Distal clavicle fractures may need surgical treatment of the ligamentous disruption even if the bony injury does not appear severe.
Surgery options include intramedullary fixation with a threaded Steinman pin (threads are though to prevent migration) and plate fixation. Conceptually, plating a clavicle is similar to plating a fibula, though differences must be kept in mind: a) the potential damage from errant drilling, etc, demands vigilance b) bigger and stronger plates may be needed for the clavicle and c) hardware prominence, never a good thing, is tolerated less well at the clavicle.
Intramedullary fixation of midshaft clavicle fractures
Plate fixation of midshaft clavicle fracture
(author's note: I hope readers can revise this section with citations to the literature. )
Complications
Mal-union and non-union are not infrequent. These were thought to not impose much morbidity, however, that has been revisited. The initial injury can also cause a neurovascular problem. Conceivably, overgrowth of the fracture callous could also cause compression.
Risk of nonunion
Robinson CM, Court-Brown CM, McQueen MM, Wakefield AE, 2004. "Estimating the risk of nonunion following nonoperative treatment of a clavicular fracture."
J Bone Joint Surg Am 86-A (7): 1359-65
[PubMed]
Abstract:
BACKGROUND: Nonunion is a rare complication of a fracture of the clavicle, but its occurrence can compromise shoulder function. The aim of this study was to evaluate the prevalence of and risk factors for nonunion in a cohort of patients who were treated nonoperatively after a clavicular fracture. METHODS: Over a fifty-one-month period, we performed a prospective, observational cohort study of a consecutive series of 868 patients (638 men and 230 women with a median age of 29.5 years; interquartile range, 19.25 to 46.75 years) with a radiographically confirmed fracture of the clavicle, which was treated nonoperatively. Eight patients were excluded from the study, as they received immediate surgery. Patients were evaluated clinically and radiographically at six, twelve, and twenty-four weeks after the injury. There were 581 fractures in the diaphysis, 263 fractures in the lateral fifth of the clavicle, and twenty-four fractures in the medial fifth. RESULTS: On survivorship analysis, the overall prevalence of nonunion at twenty-four weeks after the fracture was 6.2%, with 8.3% of the medial end fractures, 4.5% of the diaphyseal fractures, and 11.5% of the lateral end fractures remaining ununited. Following a diaphyseal fracture, the risk of nonunion was significantly increased by advancing age, female gender, displacement of the fracture, and the presence of comminution (p < 0.05 for all). On multivariate analysis, all of these factors remained independently predictive of nonunion, and, in the final model, the risk of nonunion was increased by lack of cortical apposition (relative risk = 0.43; 95% confidence interval = 0.34 to 0.54), female gender (relative risk = 0.70; 95% confidence interval = 0.55 to 0.89), the presence of comminution (relative risk = 0.69; 95% confidence interval = 0.52 to 0.91), and advancing age (relative risk = 0.99; 95% confidence interval = 0.99 to 1.00). Following a lateral end fracture, the risk of nonunion was significantly increased only by advancing age and displacement of the fracture (p < 0.05 for both). On multivariate analysis, both of these factors remained independently predictive of nonunion (p < 0.05), and, in the final model, the risk of nonunion was increased by a lack of cortical apposition (relative risk = 0.38; 95% confidence interval = 0.25 to 0.57) and advancing age (relative risk = 0.98; 95% confidence interval = 0.97 to 0.99). CONCLUSIONS: Nonunion at twenty-four weeks after a clavicular fracture is an uncommon occurrence, although the prevalence is higher than previously reported. There are subgroups of individuals who appear to be predisposed to the development of this complication, either from intrinsic factors, such as age or gender, or from the type of injury sustained. The predictive models that we developed may be used clinically to counsel patients about the risk for the development of this complication immediately after the injury.
Wick M, Müller EJ, Kollig E, Muhr G, 2001. "Midshaft fractures of the clavicle with a shortening of more than 2 cm predispose to nonunion."
Arch Orthop Trauma Surg 121 (4): 207-11
[PubMed]
Abstract:
Up to 15% of all fractures involve the clavicle. Nonunion of the clavicle is a rare complication after conservative treatment. It mainly presents as pain at the fracture site and a limited range of motion of the shoulder. The purpose of this study is to define a certain type of fracture of the clavicle that is predisposed to malunion and therefore should be treated surgically after failure of conservative treatment. Thirty-nine patients with delayed or malunion of the clavicle were analyzed. There were 13 women and 26 men. The average age of the male patients was 36.4 years (range 20-59 years) and of the female patients, 43.6 years (range 18-55 years). The mean follow-up period was 2.3 years (range 6 months to 4.2 years). All of them were treated surgically. There were 33 Allman I fractures and 6 Allman II fractures. Of the Allman I fractures, 30 (91%) were shortened by at least 2 cm. Allman I fractures were treated using a reconstruction plate or a dynamic compression plate in combination with bone grafting. The time of operation after fracture ranged from 6 weeks to 8.5 years (average 9.8 months). Pain at the fracture site was the leading symptom in all patients. At 6 months after the operation, 38 patients were free of pain with an unlimited range of motion of the shoulder. One patient (2.6%) complained of a slight weakness on the operated site. One fracture failed to unite (2.6%) and had to be replated. There were no refractures, infections, vessel or nerve lesions. To conclude, in Allman I fractures with a shortening of more than 2 cm, we recommend operative treatment in symptomatic patients if there are no signs of callus formation after 6 weeks.
Red Flags and Controversies
The question of the day is Whether to operate on mid shaft fractures.
, 2007. "Nonoperative treatment compared with plate fixation of displaced midshaft clavicular fractures. A multicenter, randomized clinical trial."
J Bone Joint Surg Am 89 (1): 1-10
[PubMed]
Abstract:
BACKGROUND: Recent studies have shown a high prevalence of symptomatic malunion and nonunion after nonoperative treatment of displaced midshaft clavicular fractures. We sought to compare patient-oriented outcome and complication rates following nonoperative treatment and those after plate fixation of displaced midshaft clavicular fractures. METHODS: In a multicenter, prospective clinical trial, 132 patients with a displaced midshaft fracture of the clavicle were randomized (by sealed envelope) to either operative treatment with plate fixation (sixty-seven patients) or nonoperative treatment with a sling (sixty-five patients). Outcome analysis included standard clinical follow-up and the Constant shoulder score, the Disability of the Arm, Shoulder and Hand (DASH) score, and plain radiographs. One hundred and eleven patients (sixty-two managed operatively and forty-nine managed nonoperatively) completed one year of follow-up. There were no differences between the two groups with respect to patient demographics, mechanism of injury, associated injuries, Injury Severity Score, or fracture pattern. RESULTS: Constant shoulder scores and DASH scores were significantly improved in the operative fixation group at all time-points (p = 0.001 and p < 0.01, respectively). The mean time to radiographic union was 28.4 weeks in the non-operative group compared with 16.4 weeks in the operative group (p = 0.001). There were two nonunions in the operative group compared with seven in the nonoperative group (p = 0.042). Symptomatic malunion developed in nine patients in the nonoperative group and in none in the operative group (p = 0.001). Most complications in the operative group were hardware-related (five patients had local irritation and/or prominence of the hardware, three had a wound infection, and one had mechanical failure). At one year after the injury, the patients in the operative group were more likely to be satisfied with the appearance of the shoulder (p = 0.001) and with the shoulder in general (p = 0.002) than were those in the nonoperative group. CONCLUSIONS: Operative fixation of a displaced fracture of the clavicular shaft results in improved functional outcome and a lower rate of malunion and nonunion compared with nonoperative treatment at one year of follow-up. Hardware removal remains the most common reason for repeat intervention in the operative group. This study supports primary plate fixation of completely displaced midshaft clavicular fractures in active adult patients.
Outcomes
Zlowodzki M, Zelle BA, Cole PA, Jeray K, McKee MD, , 2005. "Treatment of acute midshaft clavicle fractures: systematic review of 2144 fractures: on behalf of the Evidence-Based Orthopaedic Trauma Working Group."
J Orthop Trauma 19 (7): 504-7
[PubMed]
Abstract:
BACKGROUND: Fractures of the clavicle were reported to represent 2.6% of all fractures with an overall incidence of 64 per 100,000 per year (1987, Malmö, Sweden). Midshaft fractures account for approximately 69% to 81% of all clavicle fractures. Treatment options for acute midshaft clavicle fractures include nonoperative treatment (mostly sling or figure-of-eight bandage), open reduction and internal fixation with plates, and closed or open reduction and internal fixation with intramedullary pins, wires, or a nail. Most surgeons prefer nonoperative treatment of nondisplaced midshaft clavicle fractures. However, the optimal treatment option for isolated acute displaced midshaft clavicle fractures remains controversial. OBJECTIVES: This study was designed to systematically summarize and compare results of different treatment options (nonoperative, operative extramedullary fixation, and operative intramedullary fixation) in the management of midshaft clavicle fractures, specifically for displaced fractures.
Misc.
The subclavius muscle lies between the clavicle and the brachial plexus and subclavian vessels and is thought to protect these structures from damage when the clavicle is broken.
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