Proximal Humerus Fracture: Open Reduction, Internal Fixation—Intramedullary Nail

Pascal Boileau

Joseph W. Galvin

INTRODUCTION

Controversy exists as to the ideal management of proximal humerus fractures (PHFs). Plating is the most common mode of operative fixation and remains the “gold standard.” However, modern third-generation proximal humeral intramedullary (IM) nails provide unique mechanical and biological advantages in the management of PHFs. Advantages include a percutaneous procedure through the muscular portion of the rotator cuff without disruption of the supraspinatus tendon or the biologic environment at the fracture site. Additionally, IM nails provide solid tuberosity-based fixation perpendicular to the greater and lesser tuberosity (LT) fracture lines with locking screw technology and avoidance of screws oriented toward the humeral head articular surface. The purpose of this review is to describe modern surgical techniques and special tips and tricks of the trade for IM nailing of simple and complex PHFs.

INTRAMEDULLARY NAILING SURGICAL TECHNIQUE

Patient Setup and Fluoroscopic Imaging

Patient setup and fluoroscope positioning are vital to the success of PHF IM nailing. IM nailing has traditionally been described in a semisitting/beach chair position. To avoid malposition of the IM nail in height, we prefer using a strictly sitting position (90°) with the arm vertical and in neutral rotation, and the beam horizontal. Fluoroscope is brought in from the contralateral side of the table (Figure 30-1) and can be rotated to obtain orthogonal views (AP and scapular Y). The surgeon must confirm they can obtain adequate orthogonal fluoroscopic images prior to prepping and draping. Alternatively, the lateral decubitus is an option for two-part PHFs as it provides two advantages: (1) the patient’s head is not in the way of introducing the nail and (2) it avoids cerebral hypoperfusion in the elderly, which is a potential complication of the beach chair position. Meticulous attention to radiographic imaging is critical for accurate nail placement in height: the X-ray must be parallel to the lateral border of the acromion. If the nail remains too high, it will damage the rotator cuff and impinge against the acromion and the cartilage of the glenoid. If the IM nail is inserted too low, the proximal screws will miss their targets of the lesser and greater tuberosities.

FIGURE 30-1 Intraoperative patient setup and imaging.

A, The patient is in the beach chair/sitting (90°) position with the arm vertical and in neutral rotation, while the fluoroscope is horizontal, orthogonal to the arm to obtain an AP and a lateral view. B, The patient’s head or any support should not prevent entering the guidewire and nail through the superomedial (Neviaser) portal. Alternatively, the patient can be placed in lateral decubitus.

Percutaneous Intramedullary Nailing for Displaced Two-Part Surgical Neck Fractures: “Bilboquet” (“Cup and Ball”) Technique ( $percutaneous intramedullary nailing for displaced two-part surgical neck fractures: “bilboquet” (“cup and ball”) technique ( video 30-1)$ Video 30-1)

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Video 30-1

Percutaneous IM nailing for displaced two-part surgical neck fractures is an effective surgical technique with high union rates, reliable improvement in patient-reported outcomes and active range of motion, and a low rate of complications.¹^, ²^, ³^, ⁴^, ⁵^, ⁶^, ⁷^, ⁸^, ⁹^, ¹⁰^, ¹¹ ^and ¹² In displaced two-part proximal humerus fractures, the humeral diaphysis is displaced medially and anteriorly by the pull of the pectoralis major. The latissimus dorsi and teres major exert an internal rotation force on the humeral shaft. The rotator cuff is intact and holds the head in neutral rotation through the stable horizontal force couple of the subscapularis on the LT and the posterosuperior rotator cuff attached to the greater tuberosity (GT) (Figure 30-2). These fractures are ideal for IM nailing, as it is a percutaneous procedure that helps preserve fracture biology by obviating the need for opening the fracture and disrupting the periosteum. The superomedial (Neviaser) portal (posterior to the AC joint) allows passing the nail through the supraspinatus muscle belly, which avoids iatrogenic rotator cuff tendon tears and “automatically” corrects the varus/valgus tilt with realignment of the humeral head and shaft.¹³^,¹⁴ Furthermore, intraoperative impaction of the fracture site allows bony compression and reduces the risk of surgical neck nonunion. This is all performed without the need for a formal deltopectoral approach.

FIGURE 30-2 A and B, Pathoanatomy of the displaced two-part surgical neck fracture. The humeral diaphysis is displaced medially and anteriorly with internal rotation secondary to pulling forces of the pectoralis major, latissimus dorsi, and teres major muscles. The humeral head may be tilted in varus or valgus, but remains in neutral rotation; it is not rotated (or only slightly) because the anteroposterior muscle balance (horizontal force couple) is respected (ie, the rotator cuff is intact). C and D, Radiologic and functional results after percutaneous nailing of a displaced two-part surgical neck fracture in an elderly patient: This 93-year-old woman surprised us, at the visit 1 week after surgery, by pushing on her upper limbs (including the left operated one) to stand up from the table without any pain. This woman (and many others after her) informed us that IM nailing provides a stable fixation regardless of bone quality (secondary to locking screw technology); therefore, postoperative shoulder immobilization (unless for pain management during the first few postoperative days) is unnecessary.

Step 1: Establish the Start Point

The ideal start point for the IM nail is 1 cm medial to the articular margin and footprint of the supraspinatus tendon on the AP image, and in the center of the intramedullary canal on the scapular Y view. First, a long spinal needle or K-wire is placed through the Neviaser portal and confirmed to be in the optimal starting position on orthogonal imaging. The Neviaser portal (Figure 30-3A) is located posterior to the acromioclavicular (AC) joint and has many advantages as a percutaneous portal for guidewire placement and nail introduction.¹^,¹³^,¹⁴ It allows entry of the nail into the supraspinatus medially through its muscle fibers (avoiding iatrogenic rotator cuff tendon tear). This passage of the nail through the muscular portion of the supraspinatus is similar to passing the arthroscope or a cannula through the infraspinatus muscle belly for shoulder arthroscopy (Figure 30-4A-C). It does not lead to permanent rotator cuff damage.¹⁵ Additionally, it allows ease of reaching the starting point in the articular cartilage (1-cm medial to the footprint) in cases of varus tilt of the humeral head with retroversion/posterior tilt of the head (Figure 30-3B-G). In cases of severe varus of the humeral head, a small Hohmann retractor (or a Cobb) can be placed through a lateral stab incision to enter the surgical neck fracture site and reorient the humeral head. Finally, with valgus proximal humerus fractures, we recommend utilizing a portal directly adjacent to the anterolateral acromion process.¹

FIGURE 30-3 A, Percutaneous approach through the superomedial Neviaser entry portal (posterior to the AC joint) allows easily reaching the starting point on the humeral head (located 1 cm medial to the footprint) in varus proximal humerus fractures. B-G, Fluoroscopic images during percutaneous nailing of a two-part surgical neck fracture. The cannulated IM nail is introduced posterior to the AC joint (Neviaser portal) through the articular cartilage (and NOT through the cuff footprint). This allows correction of the humeral head tilt and realignment with the diaphysis. In valgus PHFs or fractures without varus, the start point for nail insertion can be accessed anterior to the acromion process.

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