Clavicle Fractures

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Clavicle Fractures

Author: L Joseph Rubino, MD, Assistant Professor, Department of Orthopedic Surgery, Wright State University
Coauthor(s): Matthew W Lawless, MD, Assistant Professor of Orthopedic Surgery, Wright State University School of Medicine; Consulting Surgeon, Department of Orthopedic Surgery, Miami Valley Hospital and Dayton Veterans Affairs Medical Center; Benjamin P Kleinhenz, MD, Resident Physician, Department of Orthopedic Surgery, Wright State University Boonshoft School of Medicine
Contributor Information and Disclosures

Updated: Jul 16, 2009

Introduction

Historically, clavicle fractures have been considered best treated nonoperatively, with good outcomes. Management typically included the use of either a shoulder sling or a figure-of-eight brace. The vast majority of these fractures healed, with variable amounts of cosmetic deformity. Studies have examined the different patterns of displacement and clinical outcomes of clavicle fractures according to their location.

Type I fracture of the distal clavicle (group II). The intact ligaments hold the fragments in place.

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Type I fracture of the distal clavicle (group II). The intact ligaments hold the fragments in place.

A type II distal clavicle fracture. In type IIA, both conoid and trapezoid ligaments are on the distal segment, while the proximal segment, without ligamentous attachments, is displaced.

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A type II distal clavicle fracture. In type IIA, both conoid and trapezoid ligaments are on the distal segment, while the proximal segment, without ligamentous attachments, is displaced.

A type IIB fracture of the distal clavicle. The conoid ligament is ruptured while the trapezoid ligament remains attached to the distal segment. The proximal fragment is displaced.

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A type IIB fracture of the distal clavicle. The conoid ligament is ruptured while the trapezoid ligament remains attached to the distal segment. The proximal fragment is displaced.

Medical literature has focused predominantly on fractures of the middle and lateral clavicle. The literature is still lacking concerning the management of medial clavicle fractures. According to current literature, medial clavicle fractures respond well to nonoperative management. Controversy remains concerning operative versus nonoperative treatment of middle and lateral clavicle fractures.^1,2,3
 

Recent studies

In a multicenter, prospective trial by the Canadian Orthopaedic Trauma Society of 132 patients with a displaced midshaft fracture, outcome and complication rates were compared for nonoperative treatment and plate fixation. Constant Shoulder scores and Disability of the Arm, Shoulder and Hand (DASH) scores were greatly improved in the operative fixation group. Mean time to radiographic union was 28.4 weeks in the nonoperative group and 16.4 weeks in the operative group. There were 2 nonunions in the operative group and 7 in the nonoperative group. Symptomatic malunion occurred in 9 of the nonoperative patients and in none of the operative ones. Most complications in the operative group were hardware-related (5 cases of local irritation or prominence of the hardware, 3 wound infections, and 1 mechanical failure). At 1 year after injury, the operative-group patients were more likely to be satisfied with the appearance of the shoulder andwith the shoulder in general than the nonoperative-group patients.⁴

Smekal et al compared elastic stable intramedullary nailing (ESIN; 30 patients) with nonoperative treatment (30 patients) of fully displaced midshaft clavicular fractures in adults 18 to 65 years of age. They were randomized to either operative or nonoperative treatment with a 2-year follow-up. Fracture union occurred in all patients in the operative group; nonunion occurred in 3 nonoperative patients. Medial nail protrusion occurred in 7 cases, and implant failure with revision surgery was necessary in 2 patients after additional trauma. DASH scores were lower in the operative group during the first 6 months and 2 years after trauma. Constant scores were significantly higher after 6 months and 2 years after intramedullary stabilization. Patients in the operative group showed a significant improvement of posttraumatic clavicular shortening and were also more satisfied with cosmetic appearance and overall outcome.⁵

For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education article Broken Collarbone.

Problem

Multiple attempts have been made to devise a classification scheme for clavicle fractures. The most common classification system is that of Allman, in which the clavicle is divided into thirds.⁶ In the Allman system, group I fractures are middle third injuries, group II fractures are lateral third injuries, group III fractures are medial third injuries. This classification scheme is still used but has been revised to include many subtypes of clavicle fractures.

Neer made a significant revision to the Allman classification scheme. Lateral clavicle fractures were further divided into 3 types based on the location of the clavicle fracture in relation to the coracoclavicular ligaments:

• Type I fractures occurred medial to the coracoclavicular ligaments.
• Type II fractures occurred at the level of coracoclavicular ligaments, with the trapezoid remaining intact with the distal segment.
• Type III injuries occurred distal to the coracoclavicular ligament and entered the acromioclavicular (AC) joint.

The reason for this modification is that lateral clavicle fractures behave differently depending on the exact location of the injury. The Neer type II fracture was further divided into type IIA, in which the conoid and trapezoid ligaments both remain attached to the distal fragment, and type IIB, in which the conoid ligament is torn.⁷

Other classification schemes have been presented since then; however, the Allman classification scheme with the Neer modification is the most commonly used and is listed in detail below.

• Group I - Fracture of middle third
• Group II - Fracture of the distal third
  • 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
  • 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

Frequency

Clavicle fractures are common injuries, representing about 4-10% of all adult fractures and 35-45% of all fractures that occur in the shoulder girdle area. If these fractures are classified into thirds, as proposed by Allman, the most frequent site of injury is at the middle third (group I fractures). These fractures account for approximately 72-80% of all fractures of the clavicle. Approximately 25-30% of clavicle fractures occur at the lateral clavicle (group II). Fractures of the medial clavicle are quite rare, accounting for 2% of all clavicle fractures in a recent epidemiological study by Nowak.⁸

Etiology

Historically, clavicle fractures were thought to result from a fall onto an outstretched hand, but more recent work has revealed that, in actuality, the most common mechanism for clavicle fractures is a fall directly onto the shoulder. A fall onto an outstretched arm was, in fact, the cause of the fracture in only 6% of cases. Data from Nowak et al and Nordqvist and Petersson cite a fall onto the shoulder as the most common cause of clavicle fractures.^8,9 Stanley et al found that about 70% of clavicle fractures were the result of trauma from traffic accidents; Pannike confirmed this statistic.^10,11 Increasing traffic density causing more motor vehicle accidents is the proposed explanation for this statistic.

Pathophysiology

Because of its subcutaneous position, the clavicle may be fractured easily, and the fracture is often an isolated injury. However, clavicle fractures are also common in the context of high-energy injury or multiple traumatic injuries. In these situations, it is important to examine the patient for other associated injuries, such as rib fractures, scapula fractures, other fractures about the shoulder girdle, pulmonary contusion, pneumothorax, hemothorax, and closed head injuries.

Presentation

Because of the clavicle's subcutaneous position, injury is often obvious and is confirmed at the time of initial observation. Despite the relatively simple diagnosis, some aspects of clavicle fractures must be addressed. In particular, note any skin abrasions or other wounds in proximity to the fracture site to determine if the fracture is an open injury. Note any tenting of the skin, as this will likely cause pressure necrosis of the skin and an increased chance that the fracture will become an open injury.

In addition to observing the status of the skin, perform a complete neurovascular examination of the involved extremity, including comparative blood pressure measurements if injury to the subclavian artery is suspected. Keep in mind that the excellent collateral circulation to the upper extremity may mask injury to the subclavian artery. The subclavian vessels and brachial plexus run in close proximity to the clavicle and are at risk for injury with displaced clavicle fractures.

Katras et al reported on a series of 7 patients with blunt trauma and an injury to the subclavian artery.¹² Four of the 7 patients had an associated clavicle fracture, and all 4 of these patients were involved in motor vehicle accidents. Only 1 of the 4 had a brachial plexus injury in addition to the clavicle fracture and subclavian artery injury.

Kendall et al reported a fatality from an isolated clavicle fracture from transection of the subclavian artery.¹³ This was the first such report in the literature; the fatality may have been due to the fact that the fall was not witnessed and the patient had lain unassisted for an unknown period of time. The patient never regained spontaneous circulation, and the injury to the subclavian artery was diagnosed at autopsy. The postmortem examination revealed a midclavicular fracture with transection of the subclavian artery. A 2.6-L hemothorax and damage to parietal and apical pleura were noted, but no other injuries were present.

Although this case is unique, it does emphasize the need to be aware of the potentially catastrophic complications of damage to the vascular structures in close proximity to the clavicle. Some findings on physical examination and workup for trauma that should alert the physician to the possibility of an injury to the subclavian vessels are hematoma overlying the clavicle, presence of a bruit over the region, diminished or absent pulses in the extremity, first rib fracture, brachial plexus injury, and a wide mediastinum on chest radiograph.

Indications

Traditionally, clavicle fractures have been treated nonoperatively, and the consensus was that they all heal. While it is true that, if all clavicle fractures are considered together, the vast majority will heal with nonoperative management, including a figure-of-eight brace or a simple shoulder sling, studies have found that in cases of specific fracture patterns and locations, not all clavicle fractures behave the same way.

Medial third fractures

Current management of medial clavicle fractures has remained nonoperative, and results have remained consistently good. Significant displacement is rare because of the extensive ligamentous attachments. However, if significant displacement occurs with this fracture, further imaging studies are warranted. A CT scan should help define the nature of the fracture displacement and the status of the nearby neurovascular structures.

Middle third fractures

The focus of treatment of middle third fractures remains nonoperative. Nonoperative treatment can be divided into 2 categories: simple support of the extremity, as in a sling or a sling and swath, and reduction and immobilization, typically with a figure-of-eight brace. These treatment options are applicable for almost all middle third clavicle fractures, with the exception of those that are severely displaced or shortened (see Image 1).

The displacing forces on a midshaft clavicle fracture.

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The displacing forces on a midshaft clavicle fracture.

No proven benefit of any specific technique of immobilization exists, so the choice of immobilization should depend on the comfort and functional demands of the patient. Immobilization may be discontinued when pain and palpable motion are no longer present at the fracture site. Stiffness is usually not a problem after nonoperative treatment of clavicle fractures. If the patient does require some rehabilitation, it should include forward elevation and external rotation. Laborers may return to light lifting after 6 weeks and full duty at 12 weeks. Athletes may return to contact sports after 3 months.

Grassi et al examined 40 patients who were treated nonoperatively with a figure-of-eight brace and 40 patients treated with open reduction and intramedullary fixation with a 2.5-mm threaded pin for uncomplicated midclavicular fractures.¹⁴ Patients who were treated nonoperatively had fewer complications and faster return to normal daily activities, heavy lifting, and sports. Overall, patients in both groups were satisfied with their results; however, 35% of the group who underwent intramedullary fixation had some adverse events during their recovery. Most of these problems were minor. However, 3 patients experienced refracture after removal of the intramedullary pin. These patients were then subsequently treated with a figure-of-eight brace, and union then occurred.

Given the excellent results obtained with nonoperative treatment of uncomplicated midclavicular fractures, nonoperative treatment in a figure-of-eight brace or regular support sling is recommended. Operative treatment is best suited for more complicated fractures of the middle third of the clavicle.

Evidence is mounting in support of operative treatment for displaced midshaft clavicle fractures.  The Canadian Orthopaedic Trauma Society performed a multicenter prospective randomized trial comparing the outcome of nonoperative treatment versus plate fixation for displaced fractures of the midshaft.⁴  Mean time to radiographic union was significantly shorter in the operative group (16.4 weeks versus 28.4 weeks).  Additionally, functional outcomes were improved at all time points measured in the operative group.  This study provided level I evidence in support of plate fixation for completely displaced midshaft clavicle fractures in the active adult population.   

Hill et al examined a subset of clavicle fractures in which initial shortening of the fracture was greater than 2 cm. They found a high rate (15%) of nonunion in this population.¹⁵ Also, final shortening of more than 2 cm was associated with unsatisfactory results. Open reduction and internal fixation of these injuries is recommended for patients with displaced middle third clavicle fractures with greater than 2 cm of shortening. Wick et al reviewed 39 nonunions of midclavicular fractures treated nonoperatively and found a correlation between initial fracture shortening of greater than 2 cm and nonunion.¹⁶ These patients subsequently underwent open reduction and internal fixation with subsequent union of the fracture. The major patient complaint for all of these nonunions was pain, and all patients had complete or near complete resolution of their symptoms. Wick, however, still recommended a trial of conservative treatment prior to open reduction and internal fixation of thesefractures.

Distal third fractures

Much controversy exists in the literature regarding the appropriate management of fractures of the distal third of the clavicle. Incidence of nonunion of displaced distal third fractures is high, and current recommendations are to fix these injuries surgically. Neer found that although distal third clavicle fractures are rare, they account for approximately half of all clavicular nonunions.¹⁷ Many different procedures have been described to fix these fractures, and intramedullary fixation is gaining popularity. However, a problem exists with migration of intramedullary wires.

Many articles have been published focusing on the treatment of distal third clavicle fractures. As mentioned previously, these injuries account for about 12-15% of all clavicle fractures.

Fractures of the distal clavicle are further divided into types I-III. In type I injuries, the coracoclavicular ligaments are intact and the fracture is usually minimally displaced or nondisplaced (see Images 2-3).

The displacing forces on a lateral clavicle fracture.

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The displacing forces on a lateral clavicle fracture.

Type I fracture of the distal clavicle (group II). The intact ligaments hold the fragments in place.

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Type I fracture of the distal clavicle (group II). The intact ligaments hold the fragments in place.

Type II fractures are at the level of the coracoclavicular ligaments and are further subdivided into IIA and IIB fractures. In IIA fractures both the conoid and trapezoid ligaments remain intact and the fracture is medial to the ligaments. Type IIB fractures involve a disruption of the conoid ligament, with the trapezoid ligament remaining intact and attached to the distal fracture fragment. Included in the IIB fracture is the more rare variant in which both the conoid and trapezoid are ruptured. Type IIB injuries tend to have significant displacement of the fracture fragments because of the loss of the downward restraint on the medial fragment from the coracoclavicular ligaments (see Images 4-5).

A type II distal clavicle fracture. In type IIA, both conoid and trapezoid ligaments are on the distal segment, while the proximal segment, without ligamentous attachments, is displaced.

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A type II distal clavicle fracture. In type IIA, both conoid and trapezoid ligaments are on the distal segment, while the proximal segment, without ligamentous attachments, is displaced.

A type IIB fracture of the distal clavicle. The conoid ligament is ruptured while the trapezoid ligament remains attached to the distal segment. The proximal fragment is displaced.

[ CLOSE WINDOW ]

A type IIB fracture of the distal clavicle. The conoid ligament is ruptured while the trapezoid ligament remains attached to the distal segment. The proximal fragment is displaced.

Type III injuries are distal to the coracoclavicular ligaments and involve the acromioclavicular joint. Type III injuries are usually minimally displaced or nondisplaced and are treated nonoperatively.

Chen et al reported 10 of 11 patients to have good-to-excellent results with their technique of repair.¹⁸ The conoid ligament is reconstructed with Mersilene tape, and the torn ligament is primarily repaired as well. The fracture is fixed with a No. 7 or smaller steel wire. The wire fixation and the Mersilene tape provide stability for the fracture, allowing the repaired coracoclavicular ligament to heal. All fractures in Chen's study united within 6 months, and 10 of 11 fractures maintained the coracoclavicular reduction. Nine of 11 patients had full relief if pain and restoration of full range of motion, and 10 of 11 patients were satisfied with the surgery and stated they would undergo the procedure again for treatment of this fracture.

Kao et al reported on 7 patients with displaced type IIA fractures and 3 patients with IIB fractures who all underwent open reduction and internal fixation with Kirschner wires (K-wires) and a tension band.¹⁹ Also included were 2 patients with comminuted distal clavicle fractures. Kao et al's technique spared the soft tissue around the fracture site, including the AC joint, with dissection limited only to the fracture site. Eleven of 12 fractures formed bony unions with this technique, and these patients experienced pain-free range of motion.

Another surgical option for lateral clavicle fractures involves using a Dacron arterial graft as a sling around the medial fracture fragment and the coracoid. This acts to stabilize the medial fragment in a reduced position in the superior/inferior plane. This procedure was performed on 11 acute distal clavicle fractures, and all of these patients' fractures united with full range of motion.

Four other patients were included in this study who were previously diagnosed as having established nonunions. These patients underwent fixation of the nonunion with a lag screw, iliac crest bone grafting, and stabilization with a Dacron sling. These patients all subsequently developed bony union of the fracture site with full range of motion. Of note, the Dacron sling did cause some slight erosion of the clavicle that was in contact with the sling; however, this did not progress and did not cause any problems for the patients. The sling is also thought to allow for the return of function of the coracoclavicular ligaments. Once the coracoclavicular ligaments reconstitute, the Dacron sling becomes redundant.

The use of Wolter clavicular plates for unstable, comminuted distal clavicle fractures was reported to result in good bony union and range of motion in all 16 patients in a series by Mizue et al.²⁰ This procedure, however, requires a second operation for removal of the plate and is only recommended for injuries that are severely comminuted and unstable.

Relevant Anatomy

The clavicle is an S-shaped bone that acts as a strut between the sternum and the glenohumeral joint. A weak spot in the clavicle bone is present at the midclavicular region, which accounts for most fractures occurring in this region. Numerous muscular and ligamentous forces act on the clavicle, and knowledge of these differing forces is necessary to understand the nature of displacement of clavicle fractures and why certain fracture patterns tend to cause problems if not reduced and surgically stabilized.

The clavicle articulates with the sternum at the sternoclavicular joint and with the acromion at the AC joint. Many ligamentous structures attach to the clavicle and provide stability for the articulations with the sternum and the acromion. The primary stabilizers of the sternoclavicular joint are the anterior and posterior capsules. Other ligamentous structures attaching here are the interclavicular ligament and the costoclavicular ligament. Stability of the sternoclavicular joint in the anterior-posterior plane is derived predominantly from the posterior capsule, with additional stability conferred by the anterior capsule. The interclavicular and costoclavicular ligaments have little effect on stability of the joint.

At the level of the AC joint, the coracoclavicular ligament and the AC ligament provide stability for the joint. The coracoclavicular ligament is actually 2 separate ligaments, the conoid and the trapezoid, which both attach from the coracoid to the inferior surface of the distal clavicle. Debski et al have delineated the different functions of the conoid and trapezoid in resistance to applied loads to the AC joint.²¹ The conoid is the predominant restraint to anterior and superior loading. The trapezoid is the major restraint to posterior loading at the AC joint. The AC ligament is at the superior-lateral aspect of the clavicle and overlies the AC joint.

Three muscles originate on the clavicle, and 3 muscles insert on the clavicle. The muscles that take their origin from the clavicle are the sternohyoid, the pectoralis major, and the deltoid. The muscles that insert on the clavicle are the sternocleidomastoid, the subclavius, and the trapezius. These muscles may become deforming forces on the clavicle in the presence of a fracture, and the displacement of fracture fragments depends on the location of the fracture in relation to the muscular and ligamentous attachments.

Many other important structures are in extremely close contact with the clavicle and are thus subject to injury in the context of clavicle fractures. The subclavian artery, which becomes the axillary artery as it passes anteriorly to the first rib, and vein are both in close proximity to the middle portion of the clavicle. Additionally, the brachial plexus also passes behind the clavicle posterolateral to the subclavian vessels and is at risk with displaced fractures of the middle clavicle. The subclavius muscle lies between the clavicle and these neurovascular structures, and, though small, it is believed to prevent more frequent damage to these structures. Reports also exist of injuries to the apices of the lung, most commonly with displaced middle third clavicle fractures.

Contraindications

Clavicle fractures are most commonly the result of a fall directly onto the shoulder.

Generally, nondisplaced or minimally displaced clavicle fractures heal with nonoperative management. Many displaced midshaft clavicle fractures can be successfully treated nonoperatively as well. These fractures tend to heal with varying degrees of cosmetic deformity from the fracture ends, typically causing a bump under the skin at the fracture site. Operative repair of these injuries is not indicated if the goal of surgery is cosmesis instead of fracture healing. Often, the surgical scar is equally, if not more, displeasing cosmetically for the patient.

Another contraindication to surgical fixation of clavicle fractures is the presence of infection, either localized in the region of the fracture or systemic. Unless the injury is open, fixing these fractures on an emergent or urgent basis is not necessary. Thus, surgery should be performed at an optimal time based on surgical risk.

출처 : http://emedicine.medscape.com/article/1260953-overview

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