Percutaneous Pinning of Proximal Humerus Fractures

Bradford O. Parsons, MD

Dr. Parsons or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Zimmer and Arthrex; serves as a paid consultant to or is an employee of Zimmer and Arthrex; and has received research or institutional support from Wyeth.

PATIENT SELECTION

Indications

Percutaneous pinning is indicated for select displaced two-, three-, and four-part fractures and in select patients. Originally described by Jaberg et al,¹ it has gained popularity and has proven efficacious, enabling a minimally invasive approach to fracture reduction, fixation, and restoration of functional outcome.²^,³^,⁴^,⁵^,⁶^,⁷^,⁸ Optimal fracture patterns include displaced surgical neck fractures without calcar or medial hinge comminution, select three-part fractures in which humeral head version and tuberosity height can be anatomically restored, and the valgus-impacted four-part fracture in which the medial hinge and calcar are intact³^,⁴^,⁵ (Figure 1). The timing of surgical management has an impact on the success of this technique; late reduction (>1 week from injury) may be difficult because hematoma and scarring diminish fracture fragment mobility and reduction.

Contraindications

Although percutaneous pinning has been successfully performed in elderly patients, osteopenic bone may pose a relative contraindication, as deficient bone quality may preclude sufficient fixation strength of percutaneously placed pin or screw fixation.² Additionally, fractures with extensive comminution of the tuberosities, medial calcar, or head segment are often not amenable to percutaneous pin and screw fixation because sufficient fixation is not afforded with this technique (Figure 2). Varus-displaced fractures, with loss of medial bone integrity, also are contraindicated because pin fixation is often insufficient to prevent redisplacement of the varus fracture fragments. Further, true three- and four-part fracture-dislocations or head-split fractures are often not amenable to percutaneous treatment. These more complex fractures with diminished bone quality, comminution, and varus displacement are indicated for formal open reduction and internal fixation with locking plate fixation or arthroplasty reconstruction.

FIGURE 1 Grashey (A) and AP (B) views of the shoulder radiographs demonstrate a valgus-impacted four-part proximal humerus fracture.

PREOPERATIVE IMAGING

Preoperative imaging requires three orthogonal plain radiographs: the true AP view with the shoulder in neutral rotation taken in the plane of the scapula (Grashey view), the scapular lateral view, and the axillary lateral view (Figure 3). Often, CT aids in the assessment of
fracture fragment positioning, angulation, and comminution and can be very helpful (Figure 4). MRI is not usually necessary or indicated.

FIGURE 2 Grashey view radiograph demonstrates a varus-displaced surgical neck fracture with medial calcar comminution. This fracture pattern is at high risk for redisplacement and is most often not amenable to percutaneous fixation. Proximal humeral locking plate fixation is most often advocated for such fractures.

VIDEO 27.1 Percutaneous Pinning: When and How to Do It. Jonathan P. Braman, MD; Evan L. Flatow, MD (7 min)

View Quicktime Video

Video 27.1

FIGURE 3 Typical trauma series of radiographs required to assess proximal humerus fractures, including a Grashey view (A), a scapular lateral view (B), and an axillary lateral view (C). The head-split component of this fracture is most evident on the axillary lateral view.

PROCEDURE

Room Setup/Patient Positioning

Patients are positioned in the beach-chair position, with the injured arm freely mobile and lateral to the table. An articulating arm positioner is routinely used. The entire forequarter is draped free. Patients are routinely anesthetized with an interscalene regional block, and general anesthesia is not usually required. Critical to the success of percutaneous management of proximal humerus fractures is the ability to obtain precise, multiplanar fluoroscopic images.⁹ A large C-arm is brought into the surgical field from the contralateral side such that a Grashey view, a scapular lateral view, and an axillary lateral view can be obtained (Figure 5). Positioning of the operating table, patient, drapes, and C-arm in a fashion that enables seamless fluoroscopic imaging of all three planes is critical; if this imaging cannot be obtained, percutaneous techniques may not be warranted. Although the steps in the video are nearly identical to those outlined here, one minor difference is the use of a mini C-arm imager, as opposed to a larger imager, which is currently routinely used.

Special Instruments/Equipment/Implants

Equipment necessary for this technique includes small elevators (eg, Cobb, Freer); bone tamps (small and large); small bone/skin hooks; and surgical clamps, which allow for portal dilation, fracture fragment mobilization, and reduction. Routinely, 3.5-/4.0-mm partially threaded cannulated screws are used to fix tuberosity fragments to the medial calcar bone, and often screw lengths of over 50 mm may be necessary in larger patients. Soft-tissue drill sleeves are critical to protect deep tissues. Rigid, terminally threaded 2.4- or 2.8-mm pins are used for shaft-to-head fixation. A large pin cutter is required to cut 2.4-/2.8-mm pins beneath the skin at the completion of fracture reduction and fixation.

FIGURE 4 Axial CT scan of the shoulder shows a head-split fracture.

FIGURE 5 Intraoperative photograph shows the recommended room setup, which is critical to successful percutaneous fixation of proximal humerus fractures. A beach-chair position is routinely used, as well as an arm holder. To enable precise, multiplanar fluoroscopic views, including Grashey, outlet, and axillary views, a large C-arm imager that comes from the contralateral side can be used.

Surgical Technique

After the patient is appropriately positioned and the affected extremity is prepped and draped, the osseous landmarks are marked on the skin. Portals are marked for fracture reduction and proximal screw fixation, as well as the orientation of the axillary nerve relative to the lateral edge of the acromion. Typical portals are marked along the lateral edge of the acromion for proximal tuberosity fixation, and the reduction portal is positioned 2 to 3 cm distal to the anterolateral acromial corner (Figure 6).

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