Open Reduction and Internal Fixation of Proximal Humerus Fractures
DEFINITION
Proximal humerus fractures may involve the surgical neck, the greater tuberosity, and/or the lesser tuberosity.
The Neer classification, which is most commonly used, categorizes fractures based on the number of displaced parts (FIG 1). This classification system involves four segments: the articular surface, the greater tuberosity, the lesser tuberosity, and the humeral shaft. Fracture fragments displaced 1 cm or angulated 45
degrees are considered a displaced part.22,23
The AO/ASIF (Arbeitsgemeinschaft für Osteosynthesefragen-Association for the Study of Internal Fixation) broadly classifies fractures into three types: type 1, unifocal extra-articular; type 2, bifocal extra-articular; and type 3, intra-articular.
Each type is then further divided into groups and subgroups.21
This system places more emphasis on the vascular supply to the humerus, with intra-articular fracture patterns having the highest risk of avascular necrosis.31
Studies have demonstrated that interobserver reliability for both classification systems is not high.1,28,29
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FIG 1 • Neer classification for fractures of the proximal humerus.
Although not included in Neer's original classification, valgus impacted fractures are a unique entity that is important to recognize.
Four-part fractures in which the humeral articular surface is impacted on the shaft segment in a valgus position, leading to an increase in the angle between the humeral shaft and the articular surface
Often minimally displaced owing to an intact rotat or cuff5
Have a lower incidence of avascular necrosis because the blood supply to the head is less likely to be disrupted
ANATOMY
The osseous anatomy of the proximal humerus consists of the greater tuberosity, the lesser tuberosity, and the articular surface.
The subscapularis inserts onto the lesser tuberosity, whereas the supraspinatus, infraspinatus, and teres minor insert onto the greater tuberosity.
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Knowledge of deforming forces associated with humerus fracture allows the surgeon to better treat proximal humerus fractures by both operative and nonoperative means.
In a two-part surgical neck fracture, the pectoralis major pulls the humeral shaft anteromedial.
In a two-part greater tuberosity fracture, the pull of the supraspinatus, infraspinatus, and teres minor tendons displaces the greater tuberosity superiorly and/or posteriorly.
With a three-part fracture involving the lesser tuberosity, the attachment site of these tendons into the greater tuberosity is intact, and the articular surface of the humeral head rotates externally to face anteriorly.
Three-part fractures involving the greater tuberosity result in unopposed subscapularis function, and the humeral articular surface rotates posteriorly.
Four-part fractures result in displacement of the shaft and both tuberosities, leaving a free head fragment with little soft tissue attachment.
An understanding of the vascular anatomy is crucial to treat fractures of the proximal humerus effectively and to predict potential risk of avascular necrosis.
The proximal humerus receives its blood supply from two branches of the axillary artery: the anterior and posterior circumflex humeral arteries.
Historically, the main blood supply to the humeral head has been thought to be the anterolateral ascending (arcuate) branch of the anterior circumflex artery10; however, there is new evidence to suggest the primary supply is from the posterior circumflex humeral artery.12
The arcuate branch runs just lateral to the tendon of the long head of the biceps in the bicipital groove, enters the humeral head, and becomes interosseous proximally at the transition between the bicipital groove and
greater tuberosity and supplies the medial aspect of the humeral head.12
The posterior circumflex humeral artery branches from the axillary artery, travels through the quadrangular space with the axillary nerve, winds superolaterally around the posterior aspect of the humerus, and supplies
the superior, lateral, and inferior aspects of the humeral head.12
The relationship of the arteries to the humerus is important when assessing risk of avascular necrosis as certain fracture patterns put these vessels at increased risk. Fractures with extension into the dorsomedial metaphysis and disruption of the medial calcar have significantly higher rates of ischemia then those that
leave these areas intact.11
PATHOGENESIS
In older patients, proximal humerus fractures usually result from a ground-level, low-energy fall.
In contrast, younger patients sustain proximal humerus fractures as the result of higher energy mechanisms such as an automobile collision or a sports-related injury (eg, extreme sports).
The presence of an associated glenohumeral dislocation can also be present and must be determined at the time of initial evaluation.
PATIENT HISTORY AND PHYSICAL FINDINGS
History should include the mechanism of injury, social situation, and preexisting shoulder symptoms, which could indicate rotator cuff pathology or arthritis.
On presentation, patients with proximal humerus fractures complain of pain in the shoulder that is made worse
with attempted movement.
Visual inspection can reveal ecchymosis and swelling of the arm and palpation generally elicits diffuse pain.
Assessment of the range of motion (ROM) may be difficult due to pain but is important to help determine the stability of the fracture. If the shaft and the proximal portion move as a unit when taken through internal and external rotation, the fracture usually is stable. If however, they do not and crepitus is felt, the fracture is unstable.
If there is an associated dislocation, it may be possible to palpate the humeral head as an anterior fullness. A thorough neurovascular examination is performed to determine the presence of associated injuries.
Patients younger than 50 years are more prone to nerve injuries. One study demonstrated nerve injury, usually of the axillary nerve, in nearly 40% of patients in this age group who sustained shoulder dislocations or surgical
neck fractures.2
Major vascular injury is very rare in these fractures; however, a high index of suspicion should be present when evaluating fractures with significant medial displacement. The axillary artery can be injured in these
instances and diminished radial and ulnar pulses should alert the surgeon to this possibility.13
IMAGING AND OTHER DIAGNOSTIC STUDIES
Initial imaging studies consist of anteroposterior, scapular Y, and axillary views.
Additional views also may include internal and external rotation views if the fracture pattern is stable. Internal rotation views help to visualize the lesser tuberosity, whereas external rotation shows the greater tuberosity. West Point axillary view may be useful for fracture of the anterior glenoid rim and a Stryker notch view for a Hill-Sachs lesion.
Traction views also may prove helpful if tolerated by the patient.
A computed tomography (CT) scan may be helpful if radiographs do not demonstrate the fracture pattern adequately.
Studies have shown that the addition of a CT scan improves intraobserver reproducibility only minimally and does not affect interobserver reliability.1
However, CT scanning may prove valuable in determining the method of fixation as well as identifying associated injuries such as Hill-Sachs fractures and bony Bankart lesions.
Indications for magnetic resonance imaging (MRI) are limited, although it may prove useful if there is any concern regarding soft tissue injuries, including the glenoid labrum and rotator cuff.
DIFFERENTIAL DIAGNOSIS
Glenohumeral dislocation Scapula fracture
Clavicle fracture Humeral shaft fracture Neurovascular injury Neuropathic arthropathy
NONOPERATIVE MANAGEMENT
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Historically, conservative treatment usually is recommended for fractures with less than 1 cm of displacement
and 45 degrees of angulation.22 About 85% of proximal humerus fractures can be treated nonoperatively.20 With newer fixation devices, however, indications for surgical management have been expanded.
There is less tolerance for displacement in isolated greater tuberosity fractures. It has been suggested that more than 5 mm of displacement leads to poor functional results.19
Neer's original description called for fixation of greater tuberosity fractures when there was more than 1 cm of displacement.22
Some authors believe that greater tuberosity displacement of greater than 5 mm may lead to impingement.
McLaughlin19 first suggested that patients in whom a greater tuberosity healed with residual displacement of more than 5 mm had long-standing pain with poor function. Displacement of less than 5 mm does not appear to warrant surgery.
Platzer et al26 looked at minimally displaced fractures of the greater tuberosity and found no statistical significance with varying degrees of displacement less than 5 mm.
For proximal humerus fractures not involving the humeral shaft, patients initially are immobilized in a simple sling.
When pain improves and the fracture moves as a unit, passive ROM is started. Patients begin with pendulum exercises, usually 2 to 3 weeks after injury, then progress to ROM in all planes.
Between 6 and 10 weeks, the fracture usually has healed enough that strengthening exercises may be started.18
When treating proximal humerus fractures conservatively, physical therapy is important to initiate as soon as
possible. Koval et al15 showed significant improvement with onepart fractures when physical therapy was initiated before 2 weeks.
Several studies have shown that nonoperative management can lead to acceptable results with proximal humerus fractures.27,30,32
Studies comparing patients treated surgically and nonsurgically have shown no difference in outcome with two-
part surgical neck fractures4 and displaced three- and four-part fractures,33 although these studies were done before the advent of periarticular locked proximal humeral plating.
SURGICAL MANAGEMENT
It is imperative that patients have reasonable expectations of their outcome following surgery. A “good” outcome is dependent on these expectations. A functional ROM with minimal pain are the goals. It is often impossible to completely restore the patients preoperative ROM.
Preoperative Planning
Acceptable imaging studies, either plain radiographs or a CT scan, are necessary before proceeding to surgery.
Each proximal humerus fracture is unique, and, in most cases, a planned method of fixation is chosen before entering the operating room. However, the definitive choice of fixation is not made until the fracture is visualized
at surgery. Consequently, the surgeon should be prepared with an arsenal of different fixation techniques.
If the fracture is not deemed suitable for internal fixation intraoperatively, the surgeon must be prepared to perform a hemiarthroplasty or a reverse shoulder arthroplasty.
Multiple techniques can be employed for surgical fixation of the proximal humerus. In this chapter, we describe several current techniques. Choice of fixation should be based on the individual patient, the fracture pattern, and the surgeon's own comfort level.
Positioning
The techniques discussed in this section are easiest to perform with the patient in the beach-chair position. With the patient nearly seated, the hips and knees are flexed. The patient is moved as far laterally as possible on the table to allow full ROM of the shoulder. A lateral buttress is used to help keep the patient in position on the table.
C-arm fluoroscopy is helpful in determining the quality of reduction. The C-arm is best positioned with the intensifier posterior to the shoulder and the arm over the patient (FIG 2).
A fluoroscopic image is obtained prior to prepping to ensure that the entire fracture can be visualized without obstruction.
Approach
The approach depends on the surgical technique to be used and is discussed further in the Techniques section. The deltopectoral approach is most commonly employed. A deltoid split may be performed in select fractures.
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FIG 2 • Positioning of the patient in the beach-chair position with fluoroscopic imaging. The C-arm intensifier should be posterior to allow for ideal visualization.
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TECHNIQUES
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Fixation of Isolated Tuberosity Fractures
The patient is placed in the beach-chair position.
A deltoid split or a deltopectoral approach may be used.
Deltoid split: An incision is made from the anterolateral tip of the acromion extending laterally down the arm.
Alternatively, an incision can be made parallel to the lateral border of the acromion, as used in open rotator cuff repair.
Skin flaps are then raised.
The deltoid is split in line with its fibers, and the anterior portion of the deltoid may be detached from the acromion.
The deltoid fibers should not be split further than 5 cm below the acromion to prevent damage to the
axillary nerve. A suture at the distal aspect of the split can help prevent inadvertent extension.14
As with all open procedures described in this chapter, the fracture should be cleaned of hematoma to facilitate reduction.
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TECH FIG 1 • A. Traction sutures are placed through the rotator cuff tendon to aid in reduction of the displaced greater tuberosity. B. Wires may be used to maintain reduction of the tuberosity. C. Screw fixation with 4.5-mm cannulated screws. (continued)
The greater tuberosity usually is displaced posteriorly or superiorly.
Abducting and externally rotating the shoulder will take tension off the posterosuperior rotator cuff, allowing the greater tuberosity fragment to be more easily reduced.
Traction sutures in the rotator cuff may prove valuable in obtaining reduction. Provisional fixation can then be obtained with K-wires (TECH FIG 1A,B).
Cannulated screws placed over the wires may then be used for definitive fixation if the wires are placed in an acceptable location.
Screws should be of the appropriate length to gain adequate purchase (TECH FIG 1C,D) but not so long
that they are symptomatic.
The use of washers may prove beneficial in patients with poor bone quality.
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TECH FIG 1 • (continued) D. Final fixation. Screws should obtain purchase in the far cortex, but they must not be long enough to damage the axillary nerve. E. Placement of suture anchors into the fracture bed. F. Reduced fracture with sutures tied over the greater tuberosity.
Alternatively, suture fixation of the greater tuberosity back to the humerus may provide better fixation than cannulated screws in those patients with poor bone quality.
This can be accomplished by placing two suture anchors into the fracture bed (TECH FIG 1E).
Both limbs of each anchor can then be brought through drill holes in the fragment and tied over the top (TECH FIG 1F).
Suture also can be placed at the bone-tendon interface of the tuberosity fragment and then through bone tunnels in the shaft, as discussed later in this section.
If the anterior deltoid was detached during the approach, it must be repaired back to the acromion using nonabsorbable sutures.
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Open Reduction and Internal Fixation of Three- or Four-Part Fractures Using Suture The patient is placed in the beach-chair position and approached through a deltopectoral interval. The rotator interval tissue may be incised. This “interval split” allows visualization of the humeral head
articular surface, if needed, in the setting of intact tuberosities and rotator cuff, as with head split patterns.
Multiple sutures are placed through the tendons of the rotator cuff, preferably no. 5 nonabsorbable sutures or 1-mm tapes.
Both the subscapularis tendon and the posterosuperior cuff tendons should be incorporated25 (TECH FIG 2A).
Drill holes should be placed distal to the fracture site. The bone on either side of the bicipital groove is of excellent quality and should hold sutures well (TECH FIG 2B,C).
In most cases, anatomic reduction is desired.
With three-part fractures involving the greater tuberosity, the head fragment should first be secured to the shaft followed by reduction of the greater tuberosity.25
For high surgical neck fractures, sutures should be placed into any remaining tuberosity on the head fragment to help maintain fixation.
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TECH FIG 2 • A. Sutures are placed through the subscapularis as well as the posterosuperior rotator cuff tendons at the muscle tendon junction. B. Suture is placed through drill holes in the proximal shaft fragment.
C. Proximal fragment fixed to the shaft with 1-mm tape through the drill holes.
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Open Reduction and Internal Fixation Using Anatomic Plating
Exposure
Anatomic plating of the proximal humerus commonly is performed through the deltopectoral interval.
With the patient in the beach-chair position, an incision is made starting from above the coracoid process and extending distally as needed along the deltopectoral groove (TECH FIG 3A).
The plane between the deltoid and pectoralis major is developed, mobilizing the cephalic vein.
Cobb elevators can be used to develop this plane, making it easier for the surgeon to identify and ligate branches of the cephalic vein (TECH FIG 3B,C).
The underlying clavipectoral fascia is identified and incised laterally to the conjoined tendon.14
The conjoined tendon is carefully retracted medially with the pectoralis major while the deltoid is retracted laterally.
Reduction
The fracture and rotator cuff are now visible. With fractures involving displaced tuberosities, we recommend obtaining control of the tuberosities with sutures placed at the bone-tendon interface (TECH FIG 4A).
Heavy sutures may be placed through the insertions of the cuff tendons and later used as supplemental fixation if necessary.
For fractures with minimally displaced tuberosities, sutures may not be needed before a reduction maneuver.
A Cobb elevator placed in the fracture site will aid in reducing the fracture (TECH FIG 4B).
The pectoralis major insertion is elevated in a subperiosteal fashion if necessary. The plate should be placed lateral to the biceps tendon so as not to disrupt the blood supply to the humeral head (TECH FIG 4C).
Often, it may be necessary to release a small portion of the anterior deltoid insertion before placing the plate.
Plate Fixation
Fluoroscopy should be used to confirm the reduction and plate placement, especially in regard to plate height, which is specific to each particular plate.
A plate positioned too high or a fracture fixed in varus may result in the plate impinging on the undersurface of the acromion.
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TECH FIG 3 • A. The incision is made extending from the coracoid process distally along the deltopectoral groove. B. Identifying the interval between the deltoid and pectoralis major. C. Using two Cobb elevators to develop the interval, bringing the cephalic vein laterally.
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TECH FIG 4 • A. Traction sutures through the tendinous attachments of the rotator cuff may be helpful in correcting varus deformity. B. Reducing the fracture by elevating the proximal fragment. C. Correct placement of the plate is lateral to the biceps tendon (not seen here). Suture fixation has been used to help maintain fixation and supplement the plate.
K-wires may be used to temporarily maintain fixation proximally and distally.
Alternatively, multiple guidewires may be placed into drill sleeves (TECH FIG 5A). Confirm plate location again, both proximally and distally, before placing screws.
Locking screws usually are placed proximally into the head first, and multiple configurations of screws are possible.
Once the head is secured to the shaft, distal screws can be placed (TECH FIG 5B).
The placement of a superiorly directed inferomedial screw to the calcar has been shown to maintain reduction and decrease the risk of postoperative varus collapse.9
Final plate placement should be confirmed fluoroscopically and the lengths of all screws closely assessed by taking the shoulder through multiple planes of motion (TECH FIG 5C,D).
Sutures placed through the cuff tendons also are secured to the plate, shaft, or other tuberosity. These
sutures may be preloaded through the plate prior to fixation.
At the completion of the procedure, the pectoralis major may be secured with sutures through holes in the plate.
In osteoporotic bone, the tuberosities can first be attached to the shaft with sutures followed by plate application.
Fixation of displaced two-part proximal humerus fractures also can be performed using a locking plate in a percutaneous fashion. With this technique, great care must be taken to prevent injury to the axillary nerve.
A recent cadaveric study8 demonstrated that the axillary nerve was an average of 3 mm from the second most proximal diaphyseal screw hole and an average of 7 mm from the third most proximal screw hole.
All other screw holes were more than 1 cm from the nerve.
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TECH FIG 5 • A. K-wires through drill sleeves are used to maintain plate fixation. Note the position of the superior aspect of the plate in relation to the top of the tuberosity. B. Once the head is secured to the plate, distal screws may be placed. C. Final plate fixation. D. Fluoroscopic image showing screw placement.
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PEARLS AND PITFALLS |
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Indications ▪ An understanding of the neurovascular anatomy as well as the deforming forces present in proximal humerus fractures is vital to treating these injuries effectively |
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and understanding which fractures require operative treatment.
Exposure ▪ Avoid devascularizing fracture fragments by minimizing soft tissue of the pieces during exposure and reduction.
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Development of the interval split aids in fracture visualization and reduction and does not require detachment of the rotator cuff tendons. This is especially helpful when trying to fix a head-splitting fracture in a young patient.
Maintaining fixation
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K-wires are useful for maintaining initial fixation.
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With suture fixation, the strong bone along the bicipital groove of the distal fragment will hold sutures the best.
Poor bone quality
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With osteoporotic three-part fractures, consider suture fixation first followed by a proximal humeral locking plate.
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Anatomic plating is very helpful when medial comminution is present.
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Superior impingement
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Avoid placing the locking plate too high on greater tuberosity.
Screw penetration
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Check the lengths of screws in multiple planes to avoid intraoperative screw perforation of the humeral head.
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POSTOPERATIVE CARE
Stable fixation must be obtained to allow for immediate ROM.
A physical therapy regimen should be established based on the stability of fixation, the fracture pattern, the quality of the bone, and individual patient factors.
Ideally, the fixation should allow physical therapy consisting of pendulum exercises, 130 degrees of passive forward flexion, and 30 degrees of passive external rotation on the first postoperative day.
Between 4 and 6 weeks after surgery, an overhead pulley can be added, with stretching and active motion added at 6 to 8 weeks.
Formal strengthening with elastic bands is not started until 10 to 12 weeks after surgery.3
As with nonoperative treatment, participation in physical therapy is key to a successful outcome.
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In a recent study looking at fixation of two- and three-part fractures, the only patients with unsatisfactory outcomes were those who were noncompliant with physical therapy.25
OUTCOMES
Flatow et al7 had excellent or good results in 12 of 16 patients with fixation of greater tuberosity fractures displaced more than 1 cm. Forward elevation averaged 170 degrees, and external rotation averaged 63 degrees.
Open reduction with suture or wire fixation can achieve acceptable fixation, especially in older patients with
osteoporotic bone. The technique can be used reliably in two- and three-part fractures.
One study showed nearly 80% excellent results with average motion of 155 degrees of average forward flexion, 46 degrees average external rotation, and internal rotation to T11. Furthermore, there were no
reported cases of osteonecrosis of the humeral head.25
Early open reduction and internal fixation with a laterally placed T-plate failed to yield consistently good results, especially for four-part fractures.17,24 Other early osteosynthesis techniques include the cloverleaf and the blade plate, but the current trend is toward anatomic plating technology.
Recent studies show promise with the use of such locking plates, although this technique is not without complications.6
COMPLICATIONS
Infection
Stiffness/adhesive capsulitis Nonunion
Malunion Avascular necrosis Nerve injury
Impingement secondary to fixation or residual tuberosity displacement
Screw perforation of the humeral head (either by incorrect length placed at the time of surgery or following varus collapse)16
Failure of fixation, including varus malposition and plate fracture following anatomic plating of proximal humerus fractures6
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