Fixation of Proximal Humerus Fractures

Michael E. Torchia, MD

Thomas S. Obermeyer, MD

Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Torchia and Dr. Obermeyer.

Adapted from Torchia ME: Technical tips for fixation of proximal humeral fractures in elderly patients. Instr Course Lect 2010;59:553-561.

INTRODUCTION

Interest in the fixation of proximal humerus fractures has grown worldwide during the past several years. This change in practice has been driven by several factors, including (1) recognition that humeral head replacement after an acute fracture has an unpredictable outcome¹; (2) understanding that posttraumatic osteonecrosis of the humeral head is not a clinical disaster²; (3) more accurate preoperative imaging using three-dimensional CT scans; (4) improvements in fluoroscopy; (5) refined reduction maneuvers³^,⁴^,⁵; and (6) improved implants, in the form of contoured locking plates. Despite these advances, clinical results are inconsistent, and the reported rates of surgical complications remain far too high.⁶^,⁷^,⁸^,⁹^,¹⁰ Most revision surgeries are due to technical problems that can be avoided with good surgical technique. This chapter focuses on techniques that have proven successful for achieving fixation of these fractures.

PATIENT SELECTION

Indications

Neer’s guidelines, published almost 40 years ago, remain useful.¹¹^,¹² Minimally displaced one-part fractures are treated nonsurgically. Most displaced fractures typically are treated with surgery. If the anticipated demands on the extremity are very low, however, it is reasonable to allow a displaced fracture to malunite and accept the motion loss caused by tuberosity impingement. Most two- and three-part fractures can be reliably fixed using modern methods, even in patients with poor bone quality. Some four-part fractures also can be treated with open reduction and internal fixation (ORIF).¹⁰^,¹³^,¹⁴ It was recently suggested that the outcome of a properly done osteosynthesis may be better than that of humeral head replacement.¹⁰

Contraindications

There are very few absolute contraindications to fixation of proximal humerus fractures. In general, patients with minimally displaced one-part fractures do not benefit from surgical treatment. Additionally, very-low-demand patients and the infirm typically are more likely to be considered for nonsurgical treatment. Many of the more severe fracture patterns do not have reliable outcomes with ORIF; these include four-part fracture-dislocations and most head-splitting fractures. Three-dimensional CT has shown that some so-called head-splitting fractures involve only a few millimeters of the humeral head and are actually a variation of the three-part patterns. These three-part variants can be treated with ORIF if the articular fracture can be visualized by opening the rotator cuff interval and/or dividing the upper portion of the subscapularis tendon and anterior capsule, preserving the circumflex vessels. We have learned that excellent fixation of proximal humerus fractures requires not only modern hardware but also traditional tension-band sutures. Thus, we generally do not attempt ORIF in patients who have associated rotator cuff tear arthropathy. Finally, the surgeon occasionally encounters elderly patients with proximal humerus fractures who have associated severe glenohumeral arthritis. Although fixation is technically feasible, arthroplasty might be a better option in this uncommon situation.

PREOPERATIVE IMAGING

When fixing proximal humerus fractures, it should be recognized that osteoporotic bone is crushed. This crushing precludes the use of “cortical reads” to reduce the fracture. Rather, the surgeon must rely on intraoperative fluoroscopic imaging to assess the quality of reduction of the tuberosities and of the head fragment on the humeral shaft. Because the anatomy of the proximal humerus is variable, a comparison radiograph of the opposite shoulder is valuable for intraoperative assessment of the quality of the reduction (Figure 1). A well-centered AP view of the scapula with the arm in external rotation clearly demonstrates the position of the greater tuberosity relative to the head (Figure 1, B). Checking this relationship intraoperatively provides the surgeon with a method of avoiding varus reductions (one of the most common complications after ORIF).⁴^,⁷^,¹⁰^,¹⁵^,¹⁶

Two-dimensional CT will often reveal the magnitude of traumatic bone loss and guide decision making about the need for bone grafting. Three-dimensional CT scans can also be useful for understanding the geometry of more
complex fractures and fracture-dislocations. Subtraction views show bony Bankart lesions and articular fractures of the humeral head that may be difficult to detect on some two-dimensional images. For three- or four-part fractures, three-dimensional CT also reveals what, if any, part of the greater or lesser tuberosity is attached to the head segment. Any area of continuity between the tuberosities and head segment may serve as a “handle” to indirectly reduce the head segment with traction sutures placed at the bone-tendon junction of the rotator cuff (the so-called string-puppet reduction technique). The use of three-dimensional CT has made it possible to plan all aspects of the case, including the exposure, reduction maneuvers, and placement of the hardware, including occasional supplemental minifragment antiglide plating (Figure 2).

FIGURE 1 Two-part proximal humerus fracture in a 95-year-old woman. A, Preoperative AP radiograph. B, AP radiograph of the contralateral shoulder with the arm in external rotation. This comparison view serves as a template for reduction. C, AP external rotation radiograph taken at follow-up. Despite shortening to gain stability, the neck-shaft angle and the position of the greater tuberosity were restored. (Reproduced from Torchia ME: Technical tips for fixation of proximal humeral fractures in elderly patients. Instr Course Lect 2010;59:553-561.)

PROCEDURE

Room Setup for Fluoroscopic Imaging/Patient Positioning

The optimal operating room setup allows unrestricted access to the shoulder for fluoroscopic imaging. Most surgeons prefer using a standard operating table and some variation of the familiar beach-chair patient position. The table is turned 90° after induction of anesthesia, so that the injured shoulder is opposite the anesthesia team and the equipment. This position allows the C-arm to enter and exit the field from the head of the operating table. Regardless of the setup and patient positioning, it is wise to verify before draping that a minimum of two high-quality fluoroscopic views can be obtained (Figure 3). This step is critical for the prevention of intraoperative screw penetration. When treating fracture-dislocations, it seems wise to also obtain a true axillary view to verify the position of the humeral head relative to the glenoid. The true axillary view is also preferred when reducing and stabilizing the lesser tuberosity.

Special Instruments/Equipment/Implants

Intraoperative fluoroscopy is essential for the assessment of fracture reduction and evaluation of screw length with reference to the subchondral bone of the humeral head.
A large Weber or “lobster claw” bone clamp is used to control the shaft segment. Heavy suture should be available to assist in tuberosity reduction and fixation.
A precontoured low-profile locking plate is the implant of choice. Smooth holes at the periphery of the plate can be used as anchor points for tension-band sutures.
Kirschner wires and Steinmann pins are useful for holding provisional reduction before definitive fixation. Larger Steinmann pins can also be used as “joysticks” to control the head segment.
A Cobb or periosteal elevator placed laterally may help to disimpact the head from the shaft and facilitate reduction of the humeral head.
In varus fracture patterns, a miniature malleable retractor (brain retractor) can be placed between the head and shaft segments. The small, thin malleable retractor can then be used like a shoehorn to assist in placement of the shaft under the head.

Bone void filler may be helpful to support the osteoporotic head segment and thus minimize the risk of fracture settling and subsequent screw penetration.

FIGURE 2 Three-part fracture-dislocation of the proximal humerus in an 87-year-old woman. A, Three-dimensional CT scan used in planning the surgical exposure and positioning the implants. B, Intraoperative photograph shows an anterior arthrotomy used for access to the glenoid rim fracture and placement of transosseous sutures. C, Postoperative AP radiograph shows placement of a minifragment antiglide plate along the medial aspect of the humerus; the pectoralis major tendon was divided and later repaired after the medial plate application. Note that the medial plate is placed well below the humeral head to preserve blood supply. D, Clinical photograph of the patient (taken at 3-month follow-up) demonstrating overhead elevation of the arm. (Reproduced from Torchia ME: Technical tips for fixation of proximal humeral fractures in elderly patients. Instr Course Lect 2010;59:553-561.)

In selected fractures with no medial support, an allograft fibular strut may be beneficial. Proximal fibular allografts fit very well within the intramedullary canal of the proximal humerus and can be drilled and fixed with locking screws. We make an effort to medialize the allograft and use the convex curve of the allograft to reproduce the “calcar” of the proximal humerus. In many shoulders, the physiologic curve of the medial calcar (Shenton line) can be used to approximate the appropriate location of the humeral head in relation to the humeral shaft, with the intervening deficient segments reconstructed with allograft strut.
For cases in which there is a question regarding the viability and condition of the humeral head, a fracture prosthesis for conversion to hemiarthroplasty or reverse arthroplasty should be available intraoperatively.

Surgical Technique

Exposure

The extended deltopectoral approach is preferred because of the options for extensile exposure to address almost any proximal humerus fracture pattern, including fracture-dislocations. The interval from the clavicle to the deltoid insertion is developed while preserving the muscle origin and releasing a portion of the insertion as needed. The subdeltoid space is mobilized with care to avoid the terminal branches of the axillary nerve. Efforts are made to correctly identify the position of the axillary nerve via the “tug test” because normal anatomic planes may be distorted from the injury. A Brown deltoid retractor is placed. Abduction of the arm relaxes the deltoid and allows access to the entire greater tuberosity and rotator cuff.¹⁷ The rotator interval is incised for several centimeters from the humeral head to the level of the glenoid, and the biceps is tenotomized intra-articularly and delivered distally so that it may be later tenodesed to the top of the pectoralis tendon. During the exposure and placement of hardware, every attempt is made to protect the primary blood supply to the humeral head.

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