DEFINITION

The clavicle is one of the most commonly fractured bones.

The site on the clavicle most often fractured is the middle third.10

The midclavicular region is the thinnest and narrowest portion of the bone. It is the only area not supported by ligament or muscle attachments.

It represents a transitional region of both cross-sectional anatomy and curvature.

It is the transition point between the lateral part, with a flatter cross-section, and the more tubular medial portion of the bone.

Because of the clavicle's S shape, an axial load creates a very high tensile force along the anterior midcortex. (Axial load makes a virtual right angle at midclavicle.)

 

 

ANATOMY

 

The clavicle is the only long bone to ossify by a combination of intramembranous and endochondral ossification.7

 

 

 

FIG 1 • A. The clavicle is S-shaped and has a double curve. The medial curve is apex anterior and the lateral curve is apex posterior. B. Proximal muscle attachments to the clavicle include the sternocleidomastoid, pectoralis major, and subclavius. Distal muscle attachments to the clavicle include the deltoid and trapezius.

 

Its configuration is S-shaped, a double curve; the medial curve is apex anterior and the lateral curve is apex posterior (FIG 1A).

 

 

The larger medial curvature widens the space for the neurovascular structures, providing bony protection. The clavicle is made up of very dense trabecular bone, lacking a well-defined medullary canal.

 

The cross-sectional anatomy gradually changes from flat laterally, to tubular in the midportion, to expanded prismatic medially.

 

The clavicle is subcutaneous throughout, covered by the thin platysma muscle.

 

The supraclavicular nerves that provide sensation to the overlying skin of the clavicle are found deep to the platysma muscle.

 

Very strong capsular and extracapsular ligaments attach the medial end to the sternum and first rib and the lateral end to the acromion and coracoid.

 

Proximal muscle attachments include the sternocleidomastoid, pectoralis major, and subclavius. Distal muscle attachments include the deltoid and trapezius (FIG 1B).

 

 

P.3713

 

The clavicle functions by providing a fixed-length strut through which the muscles attached to the shoulder girdle can generate and transmit large forces to the upper extremity.

 

PATHOGENESIS

 

The mechanism of clavicle fractures in the vast majority is a direct injury to the shoulder.11 Stanley and

associates11 studied 106 injured patients; 87% had fallen onto the shoulder, 7% were injured by a direct blow on the point of the shoulder, and only 6% reported falling onto an outstretched hand.

 

Stanley suggests that in the patients who described hitting the ground with an outstretched hand, the shoulder became the next contact point with the ground, causing the fracture. Stanley stated that a compressive force equivalent to body weight would exceed the critical buckling load to cause the clavicle fracture.

 

NATURAL HISTORY

 

In the 1960s, both Neer8 and Rowe10 published large series of midclavicle fractures, showing very low nonunion rate (0.1% and 0.8%) with closed treatment and a higher nonunion rate (4.6% and 3.7%) with operative treatment.

 

More recent studies have shown that nonunion is more common than previously recognized and that a significant percentage of patients with nonunion are symptomatic.

 

Malunion with shortening greater than 15 to 20 mm has also been shown to be associated with significant shoulder dysfunction.

 

McKee and colleagues6 identified 15 patients with malunion of the midclavicle after closed treatment. All patients had shortening of more than 15 mm, all were symptomatic and unsatisfied, and all underwent corrective osteotomy. Postoperatively, all 15 patients improved in terms of function and satisfaction.

 

Hill and associates5 reviewed 52 completely displaced midshaft clavicle fractures and found that shortening of more than 20 mm had a significant association with nonunion and unsatisfactory results.

 

Eskola and coworkers4 reported on 89 malunions of the midclavicle, showing that shortening of more than 15 mm was associated with shoulder discomfort and dysfunction.

PATIENT HISTORY AND PHYSICAL FINDINGS

 

The diagnosis is usually straightforward and is based on obtaining the mechanism of injury from a good history.

 

On visual inspection, the examiner will frequently see notable swelling or ecchymosis at the fracture site and possibly deformity of the clavicle, with drooping of the shoulder downward and forward if the fracture is significantly displaced. The skin is inspected for tenting at the fracture site and characteristic bruising and abrasions that might suggest a direct blow or seatbelt shoulder strap injury (FIG 2A,B).

 

 

 

FIG 2 • A,B. Anterior and posterior photographs of a displaced right clavicle fracture showing deformity of the clavicle and drooping of the shoulder girdle downward and forward. C. Clinical picture of a displaced right clavicle fracture, showing 3.5 cm of shortening, measured from the sternal notch to the AC joint.

 

 

Palpation over the fracture site will reveal tenderness, and gentle manipulation of the upper extremity or clavicle itself may reveal crepitus and motion at the fracture site.

 

The amount of shortening can be identified by clinically measuring the distance of a straight line (in centimeters) from both acromioclavicular (AC) joints to the sternal notch and noting the difference (FIG 2C) or by measuring directly on digital x-rays.

 

It is important to perform a complete musculoskeletal and neurovascular examination of the upper extremity and auscultation of the chest to identify the rare associated injuries; these are more frequently seen when there is a high-energy mechanism of injuries.

 

 

Rib and scapula fracture

 

Brachial plexus injury (usually traction to upper cervical root)

 

 

Vascular injury (subclavian artery or vein injury associated with scapulothoracic dissociation) Pneumothorax and hemothorax

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Two orthogonal radiographic projections are necessary to determine the fracture pattern and displacement, ideally 45-degree cephalic tilt and 45-degree caudal tilt views.

 

Usually, a standard anteroposterior (AP) view and a 45-degree cephalic tilt (FIG 3) view are adequate.

 

 

In practice, a 20- to 60-degree cephalic tilt view will minimize interference of thoracic structures.

 

The film should be large enough to include the AC and sternoclavicular joints, the scapula, and the upper lung fields to evaluate for associated injuries.

 

DIFFERENTIAL DIAGNOSIS

Sprain of AC joint

 

 

 

Sprain of sternoclavicular joint Rib fracture

 

Muscle injury

 

Kehr sign: referred pain to the left shoulder from irritation of the diaphragm, signaled by the phrenic nerve. Irritation may be caused by diaphragmatic or peridiaphragmatic lesions, renal calculi, splenic injury, or ectopic pregnancy.

 

P.3714

 

 

 

FIG 3 • Radiographs of the same displaced left clavicle fracture viewed from a standard AP projection (A) and a 45-degree cephalic tilt projection (B).

 

NONOPERATIVE MANAGEMENT

 

If the clavicle fracture alignment is acceptable, generally a simple configuration with less than 15 mm of shortening, then any of a number of methods of supporting the upper extremity may be adequate: figure-8 bandage, sling, and Velpeau dressing.

 

Nordqvist and colleagues9 reported on 35 clavicle fracture malunions with shortening of less than 15 mm. They

were all treated nonoperatively in a sling. All 35 had normal mobility, strength, and function compared to the normal shoulder.

 

A prospective, randomized study2 comparing sling versus figure-8 bandage showed that a greater percentage of patients were dissatisfied with the figure-8 bandage, and there was no difference in overall healing and alignment. The study concluded that the figure-8 bandage does little to obtain reduction.

 

SURGICAL MANAGEMENT

 

Indications for operative treatment of acute midshaft clavicle fractures are as follows:

 

 

Open fractures

 

Fractures with neurovascular injury

 

Fractures with severe associated chest injury or multiple trauma: patients who require their upper extremity for transfer and ambulation

 

 

“Floating shoulder” Impending skin necrosis

 

Fracture displacement: more than 15 to 20 mm of shortening (especially if there is associated shoulder girdle protraction and shortening)

 

In a multicenter, randomized, prospective clinical trial of displaced midshaft clavicle fractures, Altamimi and

McKee1 showed that operative fixation compared to nonoperative treatment improved functional outcome and had a lower rate of both malunion and nonunion.

 

Potential advantages of intramedullary (IM) versus plate fixation of the clavicle are as follows:

 

 

 

Less soft tissue stripping and therefore potentially better healing Smaller incision

 

Better cosmesis

 

Easier hardware removal

 

Less weakness of bone after hardware removal

 

Potential disadvantages of IM fixation of the clavicle are as follows:

 

 

 

Less ability to resist torsional forces Pin breakage

 

Pin migration

 

The recent implant design and technique described in this chapter prevents pin migration by placing a medial curve on the implant and medial implant gripper to stabilize the medial bone segment as well as a lateral screw through the implant to stabilize the lateral bone fragment.

 

Preoperative Planning

 

After the decision has been made to fix a clavicle fracture, one must evaluate whether the fracture pattern is amenable to IM fixation.

 

Fractures in the middle third of the bone are ideal.

 

The IM canal must have a large enough central canal to permit passage of the implant. This issue relates mostly

to kids.

 

Comminution and butterfly fragments (usually anterior) are common and do not preclude IM fixation as long as the medial and distal main fragments have cortical contact.

 

Positioning

 

There are two good options for patient positioning that facilitate use of a C-arm imaging device during the surgery (FIG 4A,B).

 

 

Beach-chair position of the operating room (OR) table, using a shoulder-positioning device which leaves the posterior shoulder area exposed. This is our preferred position.

 

The C-arm can be brought in from the head of the bed with the gantry rotated upside down and slightly away from the operative shoulder and oriented with a cephalic tilt. Alternatively, the C-arm can be brought in perpendicular from the opposite side of the table, which is out of the way of the surgeon. In small patients, a mini C-arm can be brought in from the surgical side.

 

The arm is prepped free and placed in an arm holder to facilitate fracture reduction.

 

The other option is to place the patient supine on a Jackson radiolucent surgical table so the C-arm can be brought in perpendicular from the opposite side of the table (FIG 4C,D).

 

 

 

A 1-L bag is placed under the affected shoulder, medial to the scapula, to aid in fracture reduction. The arm is also prepped free and placed in an arm holder to facilitate fracture reduction.

 

P.3715

 

 

 

FIG 4 • A,B. The patient is placed in the beach-chair position on the OR table, using a radiolucent shoulder-positioning device. A. The arm is prepared free and placed in an arm holder to facilitate fracture reduction. The Carm is brought in from the head of the bed with the gantry rotated upside down and slightly away from the operative shoulder and oriented with a cephalic tilt. B. The same beach-chair positioning shown sterilely draped. C,D. Alternatively, the patient is placed supine on a Jackson radiolucent surgical table. A 1-L bag is placed under the affected shoulder, medial to the scapula, and the arm is prepared free and placed in an arm holder to aid in fracture reduction. The C-arm can be brought in perpendicular from the opposite side of the table, which is out of the way of the surgeon and facilitates getting orthogonal radiographic views of the fracture: 45-degree caudal tilt view (C) and 45-degree cephalic tilt view (D).

 

TECHNIQUES

• Incision and Dissection

Drape with wide margins around the entire clavicle; mark the clavicle, fracture site, and surrounding anatomy (TECH FIG 1A).

Use the C-arm to identify the appropriate position for the incision, which should be over the distal end of

 

 

the medial fragment, in the anatomic Langer skin lines. (TECH FIG 1B). Make a 2- to 3-cm skin incision over the fracture site.

 

Divide the subcutaneous fat down to the platysma muscle (TECH FIG 1C).

 

Although there is usually very little subcutaneous fat, gently make full-thickness flaps to include skin and subcutaneous tissue around the entire incision to facilitate exposure.

 

 

 

TECH FIG 1 • A. Displaced right clavicle fracture, showing the clavicle and fracture site marked out. B. A skin incision of about 2 to 3 cm is made over the distal end of the medial clavicular fragment, in the Langer lines of normal skin creases around the neck. C. Incision over a clavicle fracture site, showing full-thickness flaps to include skin and subcutaneous tissue around the entire incision. This exposes the fascia that covers the platysma muscle. (continued)

 

 

Bluntly split the platysma muscle in line of its fibers to identify, protect, and retract the underlying supraclavicular nerves: The middle branches are frequently found near the midclavicle (TECH FIG 1D,E).

 

The fracture site is then identified while carefully preserving as much intact periosteum as possible. You may slightly elevate the periosteum at the edges of the fracture site if necessary, but there is no need for extensive periosteal stripping as with plate fixation. Maintaining the intact periosteal blood supply to the fracture fragments is an important advantage of this technique.

 

Remove any debris, hematoma, or interposed muscle from the fracture site.

 

If there are butterfly fragments, be careful to keep any soft tissue attachments.

 

 

P.3716

 

 

 

TECH FIG 1 • (continued) D. Skin incision over a displaced clavicle fracture, with underlying platysma muscle and the middle supraclavicular nerves. E. Intraoperative photo showing the platysma muscle bluntly split in the line of its fibers to identify an underlying supraclavicular nerve, which is under the clamp. The fracture site is usually easily identifiable in acute injuries because the periosteum is disrupted and usually requires no further division; as shown here, the medial clavicular fragment is easily seen. (B,D: Courtesy of Steven B.

Lippitt, MD.)

• Clavicle Preparation

   

  The following technique uses a flexible IM device which locks medially in a rigid, partially flexed position and locks laterally with a crossing screw (Sonoma Orthopedic Products, Santa Rosa, CA) (TECH FIG 2A).

   

   

   

  TECH FIG 2 • A. The Sonoma Orthopedics clavicle fixation implant. B. A bone-reducing clamp is used to elevate the medial clavicular fragment through the incision. C. Initial medial clavicle canal prep with a 2-mm drill bit to gently enter the IM canal. D. Specialized Sonoma Orthopedic awls and guidewire. E. Gentle canal penetration using Sonoma Orthopedic Products (SOP) awls. F. Full-depth penetration of the medial fragment with a spade-tipped guidewire followed by reaming with a fluted reamer.

   

   

  Use a bone-reducing clamp or towel clip to grab and elevate the medial clavicular fragment through the incision (TECH FIG 2B).

   

  Gently enter the medial fragment canal with the 2-mm drill bit.

  It is important to use the C-arm to assure appropriate orientation of the drill bit within the canal (TECH FIG 2C).

   

  The surgeon must be 100% sure that the drill bit does not skive under the clavicle toward the subclavian vein or superiorly toward the neck.

   

  P.3717

   

  The medial canal may then be prepared with either a curved awl or a reamer over a spade-tipped guidewire. Be careful to avoid penetrating the anterior cortex (TECH FIG 2D-F).

   

  Next, elevate the lateral clavicular fragment through the incision. This is facilitated by externally rotating the arm.

   

  Use the same 2-mm drill bit or awl to enter the lateral fragment under C-arm guidance (TECH FIG 3A).

   

  Then, use a 3-mm drill bit to exit the posterolateral cortex of the clavicle posterior to the conoid tubercle, along the lateral bend of the clavicle a few centimeter medial to the AC joint (TECH FIG 3B-D).

   

   

   

  TECH FIG 3 • A. After externally rotating the arm for improved exposure, a 2-mm drill bit or straight SOP awl is gently placed into the lateral canal. AP and 45-degree caudal and cephalic tilt C-arm images are used to assure accurate alignment straight down the canal. B. A 3-mm drill is then advanced past the conoid tubercle to exit the posterolateral cortex while carefully assuring proper IM alignment. C. The path of the drill must reproduce the anatomic IM canal alignment as shown with here with an implant overlying the IM canal of a bone model. D. Proper exit point posterior and medial to the AC joint capsule. E. Lateral fragment prep through two mini-incisions.

   

   

   

  A guidewire is then placed through the lateral fragment and out to the skin posterior to the AC joint. After drilling through the cortex, make a small incision over the palpable tip (TECH FIG 3E).

   

   

  Gently split the deltoid fibers and then drill the posterolateral cortex over the guidewire with the 4.5-mm reamer.

   

• Fracture Reduction and Implant Fixation

  P.3718

   

  Reduce the fracture site, and then pass the guidewire through the fracture and fully into the medial fragment (TECH FIG 4A).

   

  Then, ream over the guidewire to the full length of the prepared IM canal (TECH FIG 4B). The midpoint marking on the reamer should pass to the most medial aspect of the fracture site or slightly further. Then, measure the implant length with a depth gauge placed over the guidewire (TECH FIG 4C).

   

  A lateral entry guide is then used (TECH FIG 4D). This is placed over the guidewire. The guidewire is then removed so that the surgeon can slide the implant over the lateral guide sled into the clavicle entry site.

   

   

   

  TECH FIG 4 • A. The fracture is anatomically reduced and held in place with bone reduction clamps while the IM pin is placed all the way across the fracture site deep into the medial clavicle. B. The clavicle is then reamed while the reduction is held tight to clear the IM path for the implant. This step assures that the implant does not distract the fracture site during implantation. C. Use the depth gauge over the guidewire to measure implant length. Make sure that the flexible section of the implant bypasses the fracture site by at least 2 cm and preferably 3 cm. D. Lateral entry guide used to place over guidewire and then allow easy placement of implant into lateral clavicle entry site. E. Implant guide with lateral screw sheath overlying clavicle model for demonstration of surgical technique.

   

   

  Avoid any angular torque on the implant during penetration of the clavicle, and do not use a mallet.

   

  Once the surgeon is satisfied with the fracture reduction and implant alignment (fully seated into the medial clavicle with the flexible implant segment at least 2 cm past the fracture site), the implant is locked in its

  position with the torque driver. Engaging and turning the torque driver inside the lateral implant opening expands the medial grippers to engage the medial bone and locks the flexible distal section of the implant in a rigid position.

   

  The lateral screw is then placed through the lateral screw guide and across the implant (TECH FIG 4E).

   

   

  Accurate screw placement across the implant can be easily checked by placing the torque driver back in the end of the implant: The torque driver will bump into the cross screw inside the implant if it was placed correctly through the implant.

   

  Butterfly Fragment Management and Wound Closure

  P.3719

   

  If there is a large butterfly segmental fragment or significant comminution, it can be helpful to extend the fracture site incision posteriorly along the skin lines instead of performing two separate smaller incisions.

   

   

  If an anterior butterfly fragment exists, cerclage suture fixation is performed. Pass an elevator under the clavicle to deflect the sutures (TECH FIG 5A).

   

   

  TECH FIG 5 • A. Cerclage of an anterior butterfly fragment is accomplished by first passing an elevator under the clavicle to deflect the sutures and then passing the suture, in a figure-8 manner, through the periosteum of the butterfly fragment and around the fragment and the clavicle. B. Operative picture of butterfly fragment cerclage suture fixation. C. Radiograph of a comminuted midshaft clavicle fracture with Z-type fracture pattern and two butterfly fragments. D. Radiograph of same patient after IM fixation and cerclage suture fixation. (A: Courtesy of Steven B. Lippitt, MD.)

   

   

  Then pass a no. 2 suture in a figure-8 manner through the periosteum of the butterfly fragment and around the fragment and the clavicle (TECH FIG 5B).

   

  Close the periosteum overlying the fracture site with no. 0 absorbable suture in an interrupted figure-8 manner.

   

   

  Reapproximate the fascia of the platysma muscle using 2-0 absorbable suture. Close the subcutaneous tissue and skin incisions.

• Implant Removal

   

  The implant can be removed at 10 to 12 weeks if the fracture is healed.

   

  An incision is made over the same previous lateral incision, and the subcutaneous tissue is dissected using the hemostat until the lateral aspect of the implant is identified.

   

  The insertion/extraction jig is attached to the implant, and then the lateral cross screw is located and removed.

   

  The torque driver is then engaged inside the implant and turned counterclockwise until the tension in the implant releases the medial gripper and flexible fixation mechanism.

   

  The implant is then gently pulled or tapped out of the lateral clavicle insertion site (TECH FIG 6).

   

   

   

  TECH FIG 6 • Implant extraction device.

   

   

   

  P.3720

  PEARLS AND PITFALLS
  		Medial prep	guidewire. Use C-arm imaging.

  • First, enter the canal with 2-mm drill bit and check position with orthogonal C-arm images to make 100% sure that drill is fully inside canal. Do not miss the IM canal.

  • Next, make sure to avoid drilling or reaming out through the medial fragment cortex. This can be accomplished with a gentle twisting of the awl or with the spade-tipped

   

  • Finally, ream at least 5 cm into the medial fragment in order to assure that the wavy body passes the fracture site by 2-3 cm. Be patient. You may need multiple passes with the reamer.

     

    Lateral prep ▪ Enter the canal gently with the 2-mm drill bit and check C-arm images.

  • When passing a guidewire or 3-mm drill through the posterolateral clavicle cortex, make sure that it exits the posterior cortex adjacent to the conoid tubercle at the curve of the lateral clavicle. This will assure a straight shot down through the fracture and into the medial clavicle when passing the implant antegrade. Check images before exiting lateral cortex.

     

    Implantation ▪ First, reduce fracture, then place guidewire across fracture fully into medial segment and ream entire length over guidewire while holding fracture in anatomic reduction. This will assure that the implant does not displace the fracture slightly during the implantation process.

  • When placing the implant through the lateral entry guide and through the clavicle, gently push and rotate the implant. Do not strike the implant guide with a mallet because that can bend the flexible segment prematurely.

  • Gently rotate the torque driver as directed. Avoid aggressive torque.

 

Locking screw

• Split the deltoid as needed. Avoid bending the screw guide because that can misalign screw placement.

• Check final screw placement with C-arm image and check by placing torque driver back through end of implant. The torque driver will bump into the screw if the screw is properly placed through the implant.

 

POSTOPERATIVE CARE

 

A sling is worn for 3 to 4 weeks. During this time, the sling can be removed several times per day for active range of motion of the elbow and active-assisted range of motion of the shoulder to 90 degrees of forward flexion.

 

The sling is discontinued at 3 to 4 weeks, and full active range of motion of the shoulder is started if the fracture is healing well.

 

Progressive resistance exercises are started at 6 weeks if the patient has achieved full range of motion and there is clinical and radiographic evidence of healing.

 

Once the clavicle fracture is fully healed, the implant can be removed at 10 to 12 weeks or it can be left alone.

 

 

 

FIG 5 • A. Radiograph of displaced midshaft clavicle fracture. B,C. Postoperative radiographs of healed clavicle fracture. D. AP radiograph of bilateral clavicles after implant removal. (continued)

 

OUTCOMES

 

The authors have fixed several hundred displaced clavicle fractures with this technique. The results are excellent when the aformentioned techniques and principles are followed closely. Comminuted fractures heal very well as long as some cortical contact can be reconstructed. FIG 5 is a typical illustration of a comminuted fracture treated with this technique.

 

In a recent consecutive clinical outcome series by Basamania3 (160 clavicle fractures: 46% acute fractures, 29% malunions, 25% nonunions), there was only one mechanical hardware failure. The average postoperative American Shoulder and Elbow Surgeons (ASES) score was 95 in acute fractures and 93 in the combined group.

 

P.3721

 

FIG 5 • (continued) E. Picture of healed incision.

 

 

 

 

COMPLICATIONS

Nonunion rates are low and can be minimized by avoiding unnecessary periosteal soft tissue stripping, following procedural technical details to obtain proper fracture site compression and alignment, and encouraging patient compliance with the postoperative protocol.

Neurovascular complications are possible but can be avoided.

There is no drilling toward the neurovascular structures with this technique. When exposing the fracture site, the surgeon should stay on bone at all times.

Infection is rare, especially with this technique, which has a relatively short surgical time and small exposure. Preoperative antibiotics, meticulous handling of the soft tissues, and adequate irrigation should be part of any surgical technique.

Implant complications can occur, but these are very rare if the implant is fully seated in the medial fragment with the flexible segment more than 2 cm past the fracture site, fracture site distraction is avoided, the locking screw is properly aligned through the implant, and the patient follows the postoperative protocol.

As we observe with other minimally invasive surgeries, excellent outcomes depend on the surgeon's attention to detail and respect for the soft tissue envelope.

 

REFERENCES

1. Altamimi SA, McKee MD. Nonoperative treatment compared with plate fixation of displaced midshaft clavicle fractures. J Bone Joint Surg Am 2008;90(suppl 2, pt 1):1-8.

    

    

2. Andersen K, Jensen PO, Lauritzen J. Treatment of clavicular fractures. Figure-of-eight versus a simple sling. Acta Orthop Scand 1987;58:71-74.

    

    

3. Basamania CJ. Intramedullary fixation of clavicle shaft fractures with the Sonoma CRx clavicle fracture nail device: a consecutive case series. Presented at 12th International Congress of Shoulder and Elbow Surgery, Nagoya, Japan, 2013.

    

    

4. Eskola A, Vainionpää S, Myllynen P, et al. Outcome of clavicular fractures in 89 patients. Arch Orthop Trauma Surg 1986;105:337-338.

    

    

5. Hill JM, McGuire MH, Crosby LA. Closed treatment of displaced middle-third fractures of the clavicle gives poor results. J Bone Joint Surg Br 1997;79(4):537-539.

    

    

6. McKee MD, Wild LM, Schemitsch EH. Midshaft malunions of the clavicle. J Bone Joint Surg Am 2003;85-A(5):790-797.

    

    

7. Moseley HF. The clavicle: its anatomy and function. Clin Orthop Relat Res 1968;58:17-27.

    

    

8. Neer C. Nonunion of the clavicle. JAMA 1960;172:96-101.

    

    

9. Nordqvist A, Redlund-Johnell I, von Scheele A, et al. Shortening of clavicle after fracture, incidence and clinical significance, a 5-year follow-up of 85 patients. Acta Orthop Scand 1997;68:349-351.

    

    

10. Rowe CR. An atlas of anatomy and treatment of midclavicular fractures. Clin Orthop Relat Res 1968;58:29-42.

     

     

11. Stanley D, Trowbridge EA, Norris SH. The mechanism of clavicle fracture. A clinical and biomechanical analysis. J Bone Joint Surg Br 1988;70(3):461-464.