Distal Third Clavicle Fractures: Open Reduction and Internal Fixation

Midhat Patel

Michael D. McKee

INTRODUCTION

Distal third clavicle fractures account for approximately 25% of all clavicle fractures.¹ These injuries can be challenging to treat given the unique anatomy and bony characteristics of the distal clavicle. The clavicle broadens as it meets the acromion at the acromioclavicular (AC) joint, and the cortical density progressively decreases more distally.² The stability and management of these injuries vary based on both patient and fracture factors. Fracture factors include bone quality, how distal the fracture is, and the integrity of the coracoclavicular (CC) ligaments. These fracture characteristics determine the stability and displacement of the fracture.³ The Neer classification of distal clavicle fractures was developed based on these two factors (Table 2-1).⁴

TABLE 2-1 Neer Classification of Distal Clavicle Fractures

1	Lateral to the CC ligaments, no intra-articular involvement
2	Medial to the CC ligaments or medial to one or both ligaments with one or both ligaments disrupted
3	Lateral to the CC ligaments, intra-articular extension of the fracture
4	Transphyseal fracture seen in the skeletally immature population
5	Comminuted fracture with an inferior fragment attached to one or both CC ligaments

Nonoperative management is preferred in minimally displaced, stable fractures, including types 1, 3, and 4. In this patient population, there are low rates of nonunion with high rates of patient satisfaction. In addition, most displaced fractures may be treated nonoperatively in low-demand, elderly individuals despite a high rate of nonunion with acceptable results.⁵ Nonunion rates have been reported between 10% and 40% for distal clavicle fractures treated nonoperatively, with older age and displacement noted to be independent predictors of this complication.⁶

INDICATIONS

Absolute indications for operative treatment of distal clavicle fractures include open fractures and skin tenting with concern for soft tissue compromise. Figure 2-1 shows an example of an open distal clavicle fracture treated with a hook plate. Relative indications include concern for soft-tissue entrapment in the fracture site, polytrauma patients that may require upper extremity weight-bearing to mobilize, or significant displacement in younger, more active patients.¹ Depending on the patient, shared decision-making is important with a discussion of relative risks and benefits of surgery.

FIGURE 2-1 A, Clinical image of an open wound overlying a displaced distal clavicle fracture. B, Preoperative radiograph demonstrating a displaced distal clavicle fracture. Note the soft-tissue cleft seen in the image consistent with an open fracture. C, Postoperative radiograph demonstrating fixation with a hook plate and a screw into the coracoid for supplemental fixation.

A randomized, controlled trial evaluated operative versus nonoperative management in 59 adult patients with type II distal clavicle fractures.⁷ They evaluated functional outcome scores, patient satisfaction, return to work, and fracture healing. They found no difference in functional outcomes scores between the two groups; however, the operative group was more satisfied with their appearance and was able to return to work at a higher rate by 6 months, though neither difference persisted at 1 year. Significantly, the rate of union was significantly higher in the operative group compared with the nonoperative group at 3 months (56% vs 7%), 6 months (92% vs 39%), and 12 months (96% vs 63%). Four of 27 (15%) patients in the nonoperative group underwent surgery for symptomatic nonunion at an average of 6.5 months.⁷ In younger, active patients, particularly the patients who want to return to manual labor or athletic activities faster or patients who are concerned about the cosmetic appearance of their shoulders’ operative intervention may be indicated.

CONTRAINDICATIONS

Contraindications include active infection near the fracture and medical comorbidities that would prevent a patient from safely undergoing surgery. Historical procedures for distal clavicle fixation including K-wire fixation are also contraindicated if surgical treatment is chosen due to a high rate of migration and significant cardiopulmonary risks.⁸

Additionally, elderly, low-demand patients can be treated nonoperatively if they do not meet absolute indications for surgery. In a large series of more than 100 patients with distal clavicle fractures, Robinson et al. demonstrated that despite a nonunion rate of 41% (35 patients) in patients treated nonoperatively, only 14 patients (14%) underwent subsequent surgery for nonunion. The average age of patients with nonunion who underwent delayed surgery was 10 years younger than patients who did not have later surgery regardless of whether they achieved radiographic union.⁵ The same group also showed that older age was a significant predictor of nonunion in patients with this fracture.⁶ Therefore, the authors counsel elderly, low-demand patients with distal clavicle fractures that despite a high rate of radiographic nonunion, they can achieve satisfactory patient outcomes and do well with nonoperative management with a low risk of having a symptomatic nonunion requiring subsequent surgery.

PREOPERATIVE PREPARATION

Most distal clavicle fractures result from a direct blow over the acromion/distal clavicle area. Patients often land on the outside of the acromion, and the force is transmitted proximally into the CC joint ligaments and distal clavicle. Patients typically present with pain, swelling, ecchymosis, and visible deformity of the shoulder. Visible skin puckering or focal bruising may represent protrusion and entrapment of the proximal (shaft) fragment through the overlying deltotrapezial fascia and/or impending skin compromise. On exam, patients have tenderness to palpation over the distal clavicle as well as pain with motion of the shoulder. It is important to evaluate for associated injuries including cervical spine injuries, rib fractures, scapular fractures, neurologic injuries, and vascular injuries in the affected extremity. Temporary paresthesias are common and should be documented.⁹

In most cases, plain radiographs are sufficient for diagnosis of these injuries. The authors recommend obtaining both anteroposterior and Zanca (10°-15° of cephalad tilt) views for evaluation. A similar view of the opposite shoulder can define the normal CC distance for the patient.¹⁰ Additionally, a CT scan aids in defining anterior or posterior displacement and is ordered for specific situations: posteriorly displaced fractures, intra-articular fractures, symptomatic malunions, symptomatic nonunions, or revision surgeries.

TECHNIQUE

Treatment Options

Several treatment options have been described. Contemporary methods include fixation with one or more locking plates. Options include precontoured lateral clavicle plates and standard mini-fragment plates. In cases that have small or comminuted distal fragments, a hook plate may be fixed to the proximal segment and hooked under the acromion, capturing the distal fracture fragments beneath the plate. Supplementary stability may be added with coracoclavicular fixation to recreate the effect of the CC ligaments using a variety of techniques, including both open or arthroscopy-assisted passage of sutures or tendon graft through or around the coracoid process (see below).⁸ The authors prefer to use a precontoured distal clavicle locking plate if there is a distal fragment of bone of sufficient size and bone quality to hold fixation with multiple locking screws. If preoperative imaging or intraoperative evaluation shows a small or comminuted distal fragment that does not allow for adequate fixation, the authors use a hook plate that is fixed to the proximal shaft, overlies the distal fracture fragments, and passes through the posterior aspect of the AC joint and obtains fixation below the acromion.

Patient Positioning and Approach

The authors prefer to have the patient supine in a semi-sitting position at approximately a 45° angle. It is critical to include the patient’s arm in the sterile field, as manipulation of the arm can be important to help reduce the fracture. A padded Mayo stand or any arm positioner can be used. The sterile field should also include full access to the clavicle and sternoclavicular joint. A radiolucent table is used to allow for radiographs to be obtained. The image intensifier is brought in from the opposite side of the injury, across the patient’s body. Orthogonal views are obtained by adjusting the tilt of the image intensifier caudally to obtain a true AP of the clavicle parallel to the plate, and then cranially to obtain a view perpendicular to the plate.

An incision is made directly superior to the distal aspect of the clavicle. Dissection is carried down through the skin and subcutaneous tissue. The deltoid is split in line with its fibers and a continuous flap is created anteriorly and posteriorly for later closure. The AC joint is identified, and the capsule is carefully preserved. If there are defects in the deltoid, fascia, or AC joint capsule, these defects are extended and utilized for access to the fracture. In many cases, the proximal fragment (shaft) has “button-holed” through the trapezial fascia, and the fracture can be identified with entrapment of soft-tissue causing persistent displacement and prevention reduction. This fascia needs to be extracted from the fracture site and may later be repaired over an implant. Figure 2-2 demonstrates a distal clavicle fracture with soft-tissue entrapment that needed to be removed from the fracture site prior to fixation. In the authors’ experience, more displaced fractures tend to be more likely to have button-holed through the fascia and require open reduction.

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