J. Dean Cole
DEFINITION
From 50% to 80% of proximal humerus fractures are nondisplaced or minimally displaced and stable.12 Early range of motion after a short period of immobilization usually is sufficient to treat these fractures and has been shown to result in satisfactory outcomes.1 The remaining 20% to 50% of patients with proximal humerus fractures may benefit from operative management.
Numerous techniques of internal fixation for proximal humerus fractures have been described and reported, including cloverleaf and blade plating,1 Rush pinning,15,19 spiral pinning,18 Kirschner wire and tension band fixation,3suture and external fixation,7 and intramedullary nail fixation.8
Extensive dissection and inadequate biomechanical fixation in the context of the severe soft tissue injury and devascularization associated with these complex fracture types are the commonly cited reasons for failure of internal fixation devices.2
Prosthetic arthroplasty traditionally has been the recommended treatment for three-part fractures with osteoporosis, four-part fractures, head-splitting fractures, and articular compression fractures that involve more than 40% of the articular surface.1,2,11
Recently, several authors have reported satisfactory results with various types of osteosynthesis for four-part fractures, leading them to recommend an attempt at internal fixation in younger patients.3,4,7,16The basis of this recommendation is that subsequent published series have been unable to reproduce Neer's results with early hemiarthroplasty for four-part fractures.
Various reports have been made on the use of intramedullary nails in the proximal humerus. We prefer to use an intramedullary nail that permits stable fixation of the head to the shaft of the humerus using a minimally invasive rotator cuff–splitting approach (DePuy Inc., Warsaw, IN).
The method for treatment of proximal humeral fractures described in this chapter involves a minimally invasive anterior acromial surgical approach, an indirect method of reduction, and a unique intramedullary rod designed to permit a variety of proximal interlocking configurations.
ANATOMY
Osteology
The proximal humerus includes the humeral head, the lesser tuberosity, the greater tuberosity, and the proximal humeral metaphysis.
The position of the head is higher than the tuberosities, and changes in this relationship will cause impingement. The humeral head is slightly medial (3 mm) and posterior (7 mm) in relation to the humeral shaft (FIG 1).
The humeral head is retroverted approximately 30 degrees (range 20 to 60 degrees).
Minor losses in the humeral length between the head and the deltoid insertion can alter the deltoid length–tension ratio.
Avulsion of the greater tuberosity indicates injury to the rotator cuff.
Vascular Supply of the Proximal Humerus
The anterior and posterior humeral circumflex arteries are branches of the axillary artery.
The arcuate artery, the terminal vessel of the ascending branch of the anterior humeral circumflex artery, supplies most of the humeral head.
Avascularity of the humeral head can occur if this vessel is disrupted during a fracture of the anatomic neck.
The posterior circumflex artery becomes important in patients with proximal humerus fractures.
It may be the primary source of blood supply to the fractured head, so care should be taken to prevent additional devascularization.
Traumatic and iatrogenic vascular insult may lead to devascularization of the fracture fragments, resulting in delayed union, nonunion, and avascular necrosis. Traumatic injury cannot be predicted; well-planned minimally invasive procedures should reduce the risk of further damage, however.
Innervation
The brachial plexus is at risk in patients with upper extremity injury, and thorough neurologic evaluation is mandatory.
FIG 1 • Normal shoulder anatomy. The head is slightly higher than the tuberosities, slightly medial and posterior to the humeral shaft, retroverted 30 degrees. (Copyright J. Dean Cole, MD.)
The axillary nerve courses through the quadrilateral space, where it is at risk during fracture dislocation.
The lateral entry site for locking screw fixation (4–5 cm distal to the tip of the acromion) places the axillary nerve at risk.
PATHOGENESIS
A blow to the anterior, lateral, or posterolateral aspect of the humerus typically is the cause.
Axial load transmitted to the humerus may cause impacted fracture in osteoporotic bone.
Violent muscle contractures, as in grand mal seizures and electric shock, are associated with posterior dislocation due to overpowering internal rotators and adductors.
Pathologic causes include tumor, multiple myeloma, and metastatic or metabolic disorders.
Osteoporosis is associated with fractures of the proximal humerus (more than any other fracture).
In a three-part fracture with intact greater tuberosity, the humeral head is pulled by the supraspinatus and infraspinatus tendons; if the tendons are intact, the humeral head is externally rotated. The inverse is seen when the greater tuberosity is avulsed: the intact subscapularis internally rotates the humeral head (FIG 2).
NATURAL HISTORY
Epidemiology
4% to 5% of all fractures
Increased incidence in osteoporosis, older middle-aged and elderly persons (third most common fracture in elderly)
In persons older than 50 years of age, the female:male ratio is 4:1 (osteoporosis). Minor falls and trauma may cause comminuted fracture.
In patients younger than 50 years of age, violent trauma, contact sports, and falls from heights are responsible for fractures.
Surgical neck fracture is common.
Consequences of Injury
Nondisplaced fractures may heal without major consequences.
Acute, recurrent, or chronic dislocation
Rotator cuff tears
Neurovascular injury: axillary nerve, brachial plexus
Avascular necrosis of the humeral head often results from disruption of the arcuate artery. The axillary artery also may be damaged, but less commonly, in fracture-dislocations.
Malunion: loss of humeral length may cause deltoid weakness
Posttraumatic arthrosis
Adhesive capsulitis
Chronic pain
PATIENT HISTORY AND PHYSICAL FINDINGS
Associated injuries.
Rotator cuff tears
Dislocation
Forearm fractures
Brachial plexus, axillary, radial and ulnar nerve injuries (5%–30% of complex proximal humerus fractures)
IMAGING AND OTHER DIAGNOSTIC STUDIES
Trauma series
Scapular anteroposterior (glenoid view)
Trans-scapular
Axillary
Rotational views
CT scan
SURGICAL MANAGEMENT
Indications
Two-part proximal humerus fracture
Three-part proximal humerus fracture
Certain four-part proximal humerus fractures
Prerequisites
Shoulder table, image intensification, and experienced radiology technician
Be aware of the learning curve (do not attempt nailing of a four-part fracture before acquiring adequate experience with twoand three-part fractures).
FIG 2 • A. Fracture pattern and deforming forces. The muscular attachments of the greater and lesser tuberosities will cause abduction, external rotation, and internal rotation, respectively. The head will follow whichever tuberosity is intact. B,C. In four-part fractures, the head often is in a neutrally rotated position. (Copyright J. Dean Cole, MD.)
FIG 3 • Patient positioning should allow access of the C-arm to obtain orthogonal radiographs, which are critical in fracture reduction and fixation. A. Lateral view. B. Axial view. (Copyright J. Dean Cole, MD.)
When treating patients with complex fractures, obtain the patient's consent for a hemiarthroplasty if that is determined to be the best treatment, and have the implant available in case it is found to be necessary.
Contraindication: head-splitting, comminuted displaced humeral head fragment devoid of soft tissue attachment
Preoperative Planning
Successful intramedullary nailing of the proximal humerus fracture depends on consistent integration between image intensification and the surgical steps.
Patient positioning on a radiolucent table will allow the surgeon to use a minimally invasive approach.
Any error on the entry site will cause inevitable problems with the rest of the procedure.
It is crucial that the surgeon follow the surgical technique precisely.
Positioning
Positioning on the table must allow orthogonal and overhead axillary views.
The patient is placed supine in the beach chair position on a radiolucent table tilted at 60 to 70 degrees. The C-arm should be positioned on the opposite side of the table to allow the surgeon easy access to the proximal humerus (FIG 3).
A bolster is used to elevate the shoulder from the table and to allow shoulder extension. Extension of the shoulder is necessary to expose the entry site in the humeral head. Flexion of the shoulder will result in the acromion overlying the center of the humeral head in the sagittal plane, obscuring the entry site or errantly directing an entry angle. Anterior cutout of the nail in the head fragment can easily occur in an osteoporotic humeral head with an associated greater tuberosity fracture.
Approach
Intramedullary nailing for isolated surgical neck fractures may be performed completely percutaneously using most of the techniques described in the following paragraphs. However, when tuberosity reduction and fixation are required, a wider approach often is necessary.
The timing of the open approach depends on the sequencing of head, shaft, and tuberosity fixation. In the technique we describe in this chapter, head–shaft fixation is accomplished percutaneously using nailing and interlocking screws before tuberosity fixation. Alternatively, an open approach with tuberosity reduction and fixation can be performed before nail insertion.
The surgical approach for viewing tuberosity fractures that require fixation is a lateral deltoid-splitting approach made just below the acromion, approximately 4 cm long, that does not extend distally, to avoid injury to the axillary nerve (FIG 4A).
For a lesser tuberosity approach, a separate, small deltopectoral incision is centered just over the lesser tuberosity, and the lesser tuberosity fixation or fixation to the subscapularis tendon is performed in that plane (FIG 4B).
The rotator cuff is incised longitudinally away from the lateral watershed area of the rotator cuff and away from Sharpey's fibers and the connection of the tendon to the bone.
Significant rotator cuff defect is not created with this approach, as confirmed in cadaver dissection. The longitudinal incision on the rotator cuff does not weaken the cuff.
FIG 4 • Skin incisions. A. Deltoid-splitting incision specifically for greater tuberosity fixation. B. Deltopectoral incision specifically for lesser tuberosity fixation. (Copyright J. Dean Cole, MD.)
TECHNIQUES
K-WIRE PLACEMENT
Placement of K-wires allows fragment reduction and helps dictate placement of the skin incision and surgical approach. Hence, the first step involves placement of a K-wire in the subacromial space; it is inserted through the anterolateral aspect of the shoulder using the image intensifier (C-arm) and directed posteromedial toward the glenoid (TECH FIG 1A,B).
This initial pin will serve as a guide for the retroversion of the humeral head.
Next, two K-wires are placed in the humeral head, directed lateral to medial, one anterior and one posterior to the central aspect of the head (TECH FIG 1C,D). The wires should be separated by enough distance to allow insertion of the nail between them (1.5 cm).
The K-wires should be directed in the longest axis of the humeral head in the axial plane. Allowing for retroversion is important.
Confirmation of the correct placement in the axial plane is done by the overhead axillary view. Then the C-arm is positioned to view the advancement of the pins in the coronal plane projection.
With longer K-wires, the surgeon's hand can be kept out of radiographs. Unfortunately, with internal rotation, extension also occurs in the humerus and the humeral head, depending on the soft tissue attachments.
TECH FIG 1 • A,B. AP and axial views of initial K-wire insertion:. This initial pin will serve to orient the humeral head, specifically the desired degree of retroversion. C,D. AP and axial views of pins to control head fragment. These pins are inserted to control the head fragment in a joystick fashion. (Copyright J. Dean Cole, MD.)
FRAGMENT REDUCTION
The K-wires can then be used in a joystick fashion to adduct and extend the head, exposing the supraspinatus tendon and optimal entry site in the head from beneath the anterior edge of the acromion (TECH FIG 2A,B).
Image intensification can be used to place a K-wire through the head in line with intramedullary axis of the humerus. This maneuver includes two important aspects:
The first is to use the joysticks to extend and adduct the proximal humeral head, exposing the anterolateral portion of the head from under the acromion while simultaneously distracting the distal shaft, thereby aligning the longitudinal intramedullary axis of the proximal and distal fragments (TECH FIG 2C,D).
The second is to drive the K-wire into the head in a central position with reference to the medullary canal in the sagittal plane and lateral to central in reference to the canal in the frontal or coronal plane (TECH FIG 2E).
To achieve fracture reduction, the joysticks in the proximal fragment must be used to rotate the head while simultaneously rotating the distal shaft manually to obtain true orthogonal views of the head in reference to the shaft.
TECH FIG 2 • Fragment reduction maneuver. A,B. Combining rotation of the head fragment (K-wires) with the shaft (arm) is used to assist in fracture reduction. C,D. AP and axial views of humeral head reduction maneuver. Manipulation of the fracture fragments with the K-wires allows disimpaction of the fracture, improving the varus or valgus alignment. E. Pin entry site in humeral head. (Copyright J. Dean Cole, MD.)
GUIDEWIRE PLACEMENT
The nail can be placed percutaneous just anterior to the anterior edge of the acromion.
The anterior edge may be difficult to palpate and to differentiate from the humeral head because of edema and hematoma from the fracture. Therefore, it is helpful to locate the anterior edge of the angle of the acromion under image intensification with a K-wire where it intersects the longitudinal axis of the humerus.
Correct placement of the guidewire is crucial; it should be centered in both frontal and sagittal planes.
Manipulation of the proximal fragment has been the only reliable way to identify correct placement.
This is easily accomplished in the coronal plane, but it is more difficult in the sagittal plane. Attention should be directed at the rotational alignment.
ENTRY SITE REAMING
Reaming of the entry site should be performed carefully, as the percutaneous incision is small.
The reamer is inserted over the guidewire, and the soft tissues are retracted and protected. The reamer is advanced through the rotator cuff in “reverse” until bone contact, then on “forward” through the humeral head. The reamer is left in place.
The guidewire that was used to initiate the entry site is removed, and a longer guidewire is passed to the shaft fragment. Manipulation of the shaft fragment sometimes is necessary. The reamer's sound must be used to gauge the canal diameter. It is necessary to ream 1 mm greater than the anticipated nail size.
On some occasions, even external fixator placement from the scapular spine to the distal humerus is necessary. The external fixator is applied and distraction accomplished with manipulation of the proximal aspect of the shaft; guidewire passage usually is simple.
NAIL INSERTION
Once the nail is inserted, confirm the rotation of the humerus in the axial plane; it is necessary to ensure proper alignment before impaction (TECH FIG 3).
Usually, impaction of the distal fragment by blows against the olecranon, while supporting the proximal humeral head indirectly through the soft tissues, is adequate.
Large gaps are not acceptable, and it may be necessary to use filler substance.
TECH FIG 3 • Nail insertion. (Copyright J. Dean Cole, MD.)
INTERLOCKING SCREW FIXATION
We recommend that the oblique distal screw be the initial locking screw (TECH FIG 4). The goal of this screw is to attach the head to the shaft before fixation of the tuberosities.
Screw placement puts the axillary nerve at risk. Careful blunt dissection to bone, drilling within the sheath, and placing the screw within the confines of the sheath are necessary. Drilling should be done very carefully, although it certainly does not completely negate the risk of drilling through the humeral head. Careful observation is important.
It is occasionally helpful to remove the drill and then use a blunt guidewire and assure good humeral head subchondral bone contact before further drilling or screw placement.
Central placement of the distal oblique screw in the humeral head is important. This step should flow very smoothly if the initial K-wires have been placed in the correct axial plane alignment.
Errant placement or acceptance of poorly positioned K-wires will result only in further deviation. If the distal oblique screw is not placed at the appropriate angle, the radiographs may be deceptive and may result in screw penetration.
Screw placement on the subchondral bone is important for fixation. However, patients with osteoporosis do have a risk of the fracture fragment settling.
A and B screws are placed depending on goals of fixation.
Overdrilling to countersink the more proximal screw usually is necessary to avoid impingement.
These screws rarely are helpful in tuberosity fixation.
TECH FIG 4 • AP and axial views of intramedullary nail and proximal locking screw. (Copyright J. Dean Cole, MD.)
TUBEROSITY FIXATION
The tuberosity fixation sequence is somewhat variable.
With very displaced tuberosity fractures, if shaft-to-head fixation is performed initially with the tuberosities displaced, the guide will perforate the cuff and pin the cuff in a nonanatomic position, resulting in inability to perform reduction of the tuberosities. Therefore, if tuberosity fixation is going to be aided with the nail, the tuberosity alignment must be performed before nailing.
Another sequence involves fixation of the head and shaft followed by later fixation of the tuberosity. Anchors can be passed through the nail with sutures used later to fix the tuberosities.
The sequence of fixation should involve passing sutures through the musculotendinous junction of the subscapularis, infraspinatus, and supraspinatus. Sutures passed over the superior aspect of the head from the infraspinatus and subscapularis and sutures passed laterally around the head provide helpful, reliable fixation points. With practice, these maneuvers can be performed in a minimally invasive manner.
Comminuted tuberosity fixation is challenging. It is difficult to achieve consistent fixation with screws. A headless screw has been used with some success in limited cases.
PEARLS AND PITFALLS
POSTOPERATIVE CARE
The postoperative regimen depends on the stability of the fixation and the soft tissues.
Sling with abduction pillow that allows the proximal humerus to rest in neutral rotation and slight abduction (relax the rotator cuff and decrease tension on the greater tuberosity)
Gentle passive, pendulum, and active-assisted exercises of the shoulder
Active elbow and wrist exercises
Once fracture healing is detected on radiographic imaging, range of motion can be increased; weight lifting restrictions must be maintained until healing is complete.
COMPLICATIONS
Early
Injury to axillary nerve
Joint penetration
Loss of reduction
Infection
Lat.
Nonunion
Posttraumatic arthrosis
Avascular necrosis of humeral head
Prominent hardware
REFERENCES
· Bigliani LU, Flatow EL, Pollock RG. Fractures of the proximal humerus: In: Rockwood CA, Green DP, Bucholz RW, et al, eds. Fractures in Adults. Philadelphia: Lippincott-Raven, 1996:1055–1107.
· Connor PM, Flatow EL. Complications of internal fixation of proximal humeral fractures. Instr Course Lect 1997;46:25–37.
· Darder A, Darder A Jr, Sanchis V, et al. Four-part displaced proximal humerus fractures: Operative treatment using Kirchner wires and a tension band. J Orthop Trauma 1993;7:497–505.
· Esser RD. Open reduction and fixation of threeand four part fractures of the proximal humerus. Clin Orthop Relat Res 1994;299:244–251.
· Goldman RT, Koval KJ, Cuomo F, et al. Functional outcome after humeral head replacement for acute three- and four-part proximal humeral fractures. J Shoulder Elbow Surg 1995;4:81–86.
· Hawkins RJ, Switlyk P. Acute prosthetic replacement for severe fractures of the proximal humerus. Clin Orthop Relat Res 1993;289:156–160.
· Ko J, Yamamoto R. Surgical treatment of complex fracture of the proximal humerus. Clin Orthop Relat Res 1996;327:225–237.
· Mouradian WI. Displaced proximal humeral fractures: seven years' experience with a modified Zickel supracondylar device. Clin Orthop Relat Res 1986;212:209–218.
· Nayak NK, Schickendantz MS, Regan WD, et al. Operative treatment of nonunion of surgical neck fractures of the humerus. Clin Orthop Relat Res 1995;313:200–205.
· Neer CS. Displaced proximal humeral fractures. Part I. Classification and evaluation. J Bone Joint Surg Am 1970;52A:1077–1089.
· Neer CS. Displaced proximal humeral fractures. Part II. Treatment of three and four part displacement. J Bone Joint Surg Am 1970;52A:1090–1103.
· Norris TR. Fractures of the proximal humerus and dislocations of the shoulder. In: Browner BD, Jupiter JB, Levine AM, et al, eds. Skeletal Trauma: Fractures–Dislocations–Ligamentous Injuries. Philadelphia: WB Saunders, 1992:120–129.
· Riemer BL, D'Ambrosia RD, Kellam JF, et al. The anterior acromial approach for antegrade intramedullary nailing of the humeral diaphysis. Orthopaedics 1993;16:1219–1223.
· Robinson CM, Christie J. The two-part proximal humeral fracture: a review of operative treatment using two techniques. Injury 1993;24:123–125.
· Rush LV. Atlas of Rush Pin Technique: A System of Fracture Treatment. Meridian, MI: Bervion, 1955:166–167.
· Szyszkowitz R, Seggl W, Schleifer P, et al. Proximal humeral fractures: management techniques and expected results. Clin Orthop Relat Res 1993;292:13–25.
· Wheeler DL, Colville MR. Biomechanical comparison of intramedullary and percutaneous pin fixation for proximal humeral fracture fixation. J Orthop Trauma 1997;11:363–367.
· Yano S, Takamura S, Kobayashi I, et al. Use of the spiral pin for fracture of the humeral neck. J Orthop Science 1981;55:1607–1619.
· Weseley, MS, Barenfeld PA, Eisenstein AL. Rush pin intramedullary fixation for fractures of the proximal humerus. J Trauma 1977;17:29–37.