. Clavicle fractures. OrthopaedicsOne Articles. In: OrthopaedicsOne - The Orthopaedic Knowledge Network. Created Mar 24, 2007 05:57. Last modified Apr 04, 2007 00:24 ver.771. Retrieved 2019-10-17, from https://www.orthopaedicsone.com/x/kYAS.
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.
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.
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)
- Type V - Comminuted
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.
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.
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. )
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
The question of the day is Whether to operate on mid shaft fractures.
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.