Proximal humerus fractures are a common injury in older women, many of whom already suffer from underlying osteoporosis. The OR nurse must be knowledgeable about today's surgical treatment options for this type of injury in order to properly assist with its treatment.
A statistical overview
Approximately 5% of all fractures involve the proximal humerus (see Normal anatomy of the proximal humerus). Of that 5%, about 75% don't require surgical intervention.1 Proximal humerus fractures occur most frequently in older adults, age 70 and above, and women outnumber men with these injuries 3:1. Krishnan et al. stated that, “Fractures of the humerus...are the third most common fractures in the elderly (after hip and Colles' respectively).”2 It's important to understand the mechanisms and classifications of injuries in relation to the type of surgical intervention they require. This article will outline those, as well as a variety of surgical treatments being utilized today for proximal humerus fractures.
Defining the problem
Figure. Neurovascula...Image Tools
Most patients who have proximal humerus fractures will present to the ED with complaints of pain and loss of function.3 These patients will have significant shoulder swelling associated with ecchymosis tracking into the arm and chest.2 It's important to assess for other parallel injuries, such as head or thoracic trauma, and other fractures.2 Since most patients who suffer from proximal humerus fractures are older adults, it's also possible that cardiac or neurologic etiology may have contributed to the fall.2 In patients who experience a fall, it's also important to assess for other injuries including simultaneous fractures of the wrist, elbow, or hip. In addition, there should be a detailed history to assess for either indirect or direct mechanisms of injury, or whether seizure or electrical shock was involved, since these can predispose patients to dislocations as well.3
A thorough neurovascular assessment of the affected extremity is indicated since the axillary nerve is the most commonly injured nerve associated with these fractures (see Neurovascular structures of the shoulder).3 Krishnan et al. stated that a majority of patients with proximal humerus fractures have neurologic injury to either the axillary and/or scapular nerve.2 Proper management of the injury will require documentation of this finding if present.2 In addition, peripheral pulses should be documented, as well as pulsatile or expanding hematomas, which could indicate a vascular lesion.2
Radiologic work-up will include a Neer “trauma series” with anteroposterior, scapular, and axillary views. A CT scan may also be indicated if plain X-rays aren't sufficient. This can clarify the extent of tuberosity displacement, size of humeral head indentation fractures, and extent of articular involvement with head comminution.4 Preoperative lab studies should include a basic metabolic profile (BMP) to assess liver and kidney function and electrolytes, complete blood count (CBC), type and cross match, and coagulation studies.3
Classifying the fracture
Fractures of the humerus are classified as either nondisplaced (unseparated fracture fragments without the need for surgical intervention) or displaced (separated fracture fragments that usually require fixation) and can occur by two basic mechanisms. An adduction, or direct injury, results from axial forces on the humerus in a caudal direction to the acromion,1 such as falling on the elbow. This can cause comminution of the medial calcar at the anatomical neck with varus malalignment of the humeral head in relation to the shaft–these are typically two- and three-part fractures. In comparison, abduction, or indirect injuries, can occur with a fall on an outstretched arm that causes axial force to the glenoid.1 The humeral head is then impacted into a valgus position that more commonly results in four-part fractures. Studies have shown that the risk of avascular necrosis (AVN) rises in conjunction with increased fracture fragments and the amount of displacement.
A closer look at fractures
Figure. Proximal hum...Image Tools
In 1934, Codman first observed that fractures of the proximal humerus follow the epiphyseal plate and occur in four segments: articular surface of the humeral head, humeral shaft, and the greater and lesser tuberosities (see Proximal humerus fracture).4 In 1970, Neer elaborated on Codman's observation by including the four segments along with rates of displacement and vascular isolation.4 In addition, a fragment was considered displaced if there was more than 1 cm of separation and more than 45 degrees of angulation.5 Cariati et al. described the various types of Neer classification fractures as follows:
* Two-part fractures–include any of the four parts and one displaced fragment
* Three-part fractures–displaced fracture of the surgical neck in addition to a displaced tuberosity
* Four-part fractures–displaced fractures of the surgical neck and both tuberosities.4
Although not commonly used, the Mueller AO long bone fracture classification system classifies long bone fractures according to injury severity and the likelihood of developing AVN of the humeral head.4 Due to its simplicity and standard language, Neer classification is still the most commonly used.
Treating the fracture
Fakler et al. cited a prospective epidemiologic study that showed that 49% of proximal humerus fractures were attributed to Neer type I group (minimally displaced).1 Conservative medical treatment is indicated in these instances, and the extremity is placed in a shoulder immobilizer with padding in the axilla to prevent skin chaffing.3 Nondisplaced humeral fractures are usually stable, and gentle range of motion can begin after 7 to 10 days, with physical therapy initiated after 3 weeks.3
Krishnan et al. described an evidence-based treatment algorithm for surgical repair of proximal humerus fractures that included age, bone quality, fracture pattern, and timing of surgery.2 Age is the first and most important factor in deciding how to repair a proximal humerus fracture. Since osteoporosis is common in patients over 70, this demographic tends to fare better with arthroplasty. Although the development of new plate designs has improved the ability to repair fractures in osteoporotic bone, there are high rates of complications with their use. Patients under 70 have higher success rates with joint preservation techniques of fixation.2 In terms of fracture pattern, an intact medial humeral calcar seems to be the best predictor of the necessary fracture stability for successful healing.2 Krishnan et al. further stated that calcar comminution can make fracture stability impossible even with anatomic reduction.2 Timing between the injury and surgery is the last variable. A simpler procedure, such as percutaneous pinning, may be prevented if surgery is delayed and early callus forms.2 In addition, arthroplasty for fractures older than 4 weeks has very different results from those managed more acutely.2
CRPP—a less invasive approach
Although minimally invasive techniques generally offer inferior stability when compared with intramedullary devices and plating,1 closed reduction and percutaneous pinning (CRPP) is an alternative option for selected patients.5 Magovern et al. stated that CRPP offers superior bone healing, less risk of AVN, decreased internal scarring, and improved postoperative appearance.5 Fractures that can be considered for CRPP include two- and three-part fractures of the surgical neck, greater and lesser tuberosities, and four-part valgus-impacted fractures.5 Specific conditions are required for this procedure to be successful, including a stable closed reduction, healthy bone quality, minimal comminution, an intact medial calcar, and a cooperative patient.5 Therefore, this procedure is generally reserved for patients 60 or younger, which is a smaller percentage of those who require the surgery.
The procedure is easiest to perform with the patient in a beach-chair position at 20 degrees to 30 degrees. The patient should be in a far lateral position on the table with thoracic support to prevent falling.5 The head should be immobilized in a holder, and the affected extremity draped for easy mobility and fluoroscopic imaging.5 Because obtaining closed reduction is the key to this procedure, a post may be placed between the arm and chest to allow shaft lateralization by the surgeon.5
Percutaneous fixation includes 2.5 mm pins and guide wires for a 6.5- or 7.3-mm cannulated screw set.5 Terminally threaded fixation is necessary for good bone purchase to reduce the risk of migration.5 For surgical neck repair, the pins are positioned in retrograde from the shaft up to the head.5 Cannulated screws may also be used based upon bone quality and the surgeon's preference. Pins are cut below the skin surface and are never left protruding due to the risk of infection.5 At the end of the case, the shoulder will be moved through a range of motion under fluoroscopy to assure stability of the construct.5
Postoperatively, the arm is placed in a sling for several weeks with motion allowed below the elbow and regular pendulum exercises. The tuberosity pins can be removed at 3 to 4 weeks, while the retrograde pins can be removed after 4 to 6 weeks.5 X-rays are taken weekly until complete pin removal to ensure reduction and that migration isn't occurring. Once all of the pins are removed, active range of motion can progress if X-rays reveal proper healing. Strengthening is delayed for approximately 12 weeks until union is complete.5 Common complications can include pin migration into major vascular structures, infection, AVN, neurovascular injury, and mal- or nonunion. Magovern et al. stated that clinical outcomes have shown 70% favorable to excellent results.5
Intramedullary nail implants have been the standard for long bone fixation for quite some time. In recent years, this product has been designed specifically for the proximal humerus and includes locking screws that allow for fixation of the tuberosities to the humeral head fragment (see Intramedullary nailing). While nail fixation shares similar patient considerations with percutaneous pinning, the pattern of injury must be carefully assessed when a surgeon considers this treatment.
The first consideration is head vascularity. For the older adult with existing osteoporotic bone, arthroplasty is usually the most efficient solution. However, in younger patients with better bone stock, head preservation is always a priority. The orientation of the tuberosities to the head is also a significant factor. For an optimal outcome, reduction is recommended for fragments with displacement of 5 mm or greater.6 If it is determined that head and tuberosity orientation can be restored, then head to shaft stability must be considered.6 Young et al. stated that locked intramedullary nailing is recommended for displaced fractures when the head is unstable to the shaft.6
Patients should be placed in a beach-chair position with their shoulders off the edge of the table and proper support to the thorax. Fluoroscopy is used to assess stability of the fracture as well as manipulation of the fragments. Closed nailing can be used for two-part surgical neck fractures with a limited anterior deltoid approach. Three- and four-part fractures usually require open reduction through a deltopectoral incision–a deltoid retractor may be used to aid in exposure.6 Heavy nonabsorbable polyester sutures can be placed at bone-tendon junctions to aide in control of the tuberosities during reduction and fixation. A bone tamp will be used to reduce the head while traction is applied with the sutures.6 The surgeon will progress through the procedure in a sequential fashion, converting four- and three-part fractures to three- and two-part fractures, respectively.6 After reduction, Kirschner wires (K wires) can be used for temporary fixation while the intramedullary nail is being inserted. A 1 cm split is made at the supraspinatus tendon. An awl can be used to make the initial hole–which can then be enlarged with a drill–while the head and shaft are reamed in preparation of the nail.6 The nail can be inserted with manual pressure and screws, and then inserted through a cannula at differing angles into the tuberosity fragments.6 A laminar spreader can be used to provide distraction or compression of the head/tuberosities to the shaft.6 If a high-energy impact causes the fracture to extend into the shaft with comminution, a longer nail is indicated along with distal interlocking screws.6 At the conclusion of the procedure, the extremity is taken through a range of motion under fluoroscopy to assure proper fixation.
Postoperatively, patients are immobilized at 15 degrees of external rotation and placed in an abduction brace.6 While active elbow and wrist exercises are started immediately, passive shoulder range of motion exercises can begin at 3 weeks.6 At 6 weeks postop, patients begin active exercises, while strengthening against resistance can proceed at 12 weeks with radiographic evidence of union.6 Even though this type of procedure has been shown to be successful in managing proximal humerus fractures, studies have shown complication rates of up to 50%.6 The majority of these complications were attributed to the proximal screws backing out. However, newer implant designs are reducing this occurrence. AVN, delayed union, and stiffness accounted for other smaller percentage complications.6
Figure. Intramedulla...Image Tools
Locking plates for patients with osteoporosis
Angular stable locking plates are another method of fixation that preserve the humeral head surface. This technique can be an alternative to arthroplasty for patients with osteoporosis because of their fixed angle, and multiple locking screws that capture a larger bone volume. The construct is comprised of an angled, threaded plate–which is contoured to the lateral aspect of the proximal humerus–and fixed with threaded screws. A locked screw acts as a load-carrying lever, while the nonlocked screw is a fixation component that presses the plate against the bone.1
The patient is placed in the beach-chair position with access to the shoulder; the fluoroscopic C-arm is positioned on the opposite side of the table. An anterior deltopectoral approach is used, and a deltoid retractor is inserted to expose the fragments. Temporary sutures can then be used to control the fragments during reduction.7 A drill guide determines the correct length of the screw. The head can then be stabilized with five fixed-angle screws aligned in various planes.8 At least two of these screws are used in the shaft, and three on the osteoporotic bone.8 If suture loops were previously placed, they are then threaded though the plate's holes and knotted.8 A bone graft, or a graft substitute, may be necessary for metaphyseal defects and is placed beneath the humeral head and tuberosities to aid the locking plate in maintaining reduction.7 It's important that the arm is taken through passive motion while under fluoroscopy to assess correct positioning of the screw. A suction-type drain will be inserted with layered wound closure.8 Drosdewech stated that the goal of open reduction and internal fixation is to obtain fragment reduction with rigid fixation to allow early range of motion.7
Complications of the proximal humerus locking plates are related to its thin contour, titanium notch sensitivity, and bending if there's a lack of medial calcar support.7 AVN is, again, common with four-part fractures, and intraoperative fluoroscopy is critical to avoid screw penetration into the joint space.7
Alternatives to locking plates
Primary hemiarthroplasty is indicated for optimal rehabilitation in patients with four-part humeral head fractures of the dominant arm, especially those with underlying osteoporotic bone. Even though locking plates may also be used in these types of fractures, the surgeon must carefully evaluate the patient because secondary prosthetic placement after an initial fixation leads to worse functional results than primary placement.9 Retrospective studies of patients that underwent hemiarthroplasty after proximal humerus fractures revealed that 93% were pain-free.2
Prior to the surgery, plain X-rays may be obtained on both shoulders to determine the desired height of the humeral head. Again, the patient is placed in a beach-chair position, and a deltopectoral incision is made. Temporary sutures are placed around the greater and lesser tuberosities so that they may be gently retracted while the head is removed and measured with a caliper.2 Once the prosthetic head size is determined, a bone graft is procured from the humeral head fragment.2 The medullary canal is prepared manually with cylindrical reamers and fitted with trial implants.2 A preselected trial head is then placed onto the fracture-specific prosthetic stem.2 If the medial calcar is fractured, it can be fixated with wire or heavy suture.2 The surgeon will drill two holes into the proximal shaft so that nonabsorbable mattress sutures can be used as tension bands for the final tuberosity repair and the prosthetic stem will then be cemented.2 Finally, the bone graft wedges will be placed in three different sites: in the prosthetic window, under the greater tuberosity at the lateral prosthetic fin, and at the medial edge between the prosthetic head and the neck of the implant.2
Reverse total shoulder arthroplasty
An additional option for complex fracture pathology is the reverse total shoulder arthroplasty. The procedure is similar to hemiarthroplasty, but contains two separate implants. First, the shoulder capsule and tuberosity fragments are removed, and the humeral shaft is retracted to expose the glenoid.10 Next, the glenoid is reamed to bleeding, and a glenoid base plate is then fixed with convergent screws, superiorly in the base of the coracoid and inferiorly into the scapula.10 Finally, the humeral component is cemented, and the biceps tendon sutured to the lateral fin of the humeral implant.10
For either type of procedure, the shoulder is then moved through a range of motion and postoperative radiographs are obtained.2 A drain is usually inserted, and the arm is placed in an immobilizer or other appropriate sling for approximately 6 weeks. Immediate supine passive motion can be initiated on postop day 1, active motion after 7 weeks, and resistance exercises after 10 weeks.2 Complications usually include septic or aseptic loosening and dislocation.
Transosseous suture fixation
A less frequently described method of proximal humerus fracture repair is the technique of transosseous suture fixation for two-, three-, and four-part fractures. The positioning is essentially the same for this as for the previously described methods. A lateral transdeltoid approach is used and extends laterally and distally for 6 to 7 cm.11 Soft-tissue attachments are preserved to protect vascularization of the head.11 Heavy, nonabsorbable sutures are passed through each of the fragments; holes are drilled into the diaphysis or metaphysis (depending on the fracture type) for sutures to be inserted. Then, each suture is tied individually to the other in a cruciate fashion to allow fixation of all parts.11 When completed, there will be eight sutures for a four-part fracture, six for a three-part, and five for a two-part. After stabilization of the fracture, the extremity is mobilized for up to 90 degrees of abduction and 30 degrees of external and internal rotation.11
An immobilizer secures the arm to the chest and can be converted into a sling on postop day 2.11 Pendulum exercises also begin on postop day 2 and continue until the fourth week, active-assisted range of motion until the tenth week, and active motion and strengthening until 6 months out.
The nurse's imperative
Proximal humerus fractures can occur in a variety of complex fashions. The OR nurse plays a significant part in ensuring patient safety from further injury and quality of outcomes.
© 2012 Lippincott Williams & Wilkins, Inc.