Proximal Humerus Fractures

Osteology

The anatomy of the proximal humerus is highly variable. Multiple cadaveric studies have been performed to compare anatomic relations that are constant among individuals. Unfortunately, few exist. The critical anatomic relations of the proximal humerus are those of the articular segment to the shaft and the tuberosities. These include retroversion, inclination angle, and translation of the head relative to the shaft, as well as the relation of the head to the greater tuberosity.

On average, the articular segment is retroverted 30° relative to the forearm. The range is quite large (0-70°) and can vary from one side to the other. Inclination of the articular segment also can vary (from 120º to 140°).

The head segment can lie directly over the medullary canal but often is translated either posteriorly or medially. Therefore, if a prosthetic replacement is placed in the intramedullary canal, a resultant shift in position of the articular segment can occur unless some design feature of the prosthesis allows for a simultaneous shift in the prosthetic head position. Finally, the proper anatomic relations of the prosthetic head must be reconstructed meticulously to avoid overreducing the tuberosity to the head height.[4]

The articular head always lies above the greater tuberosity, but the difference can range from 3 to 20 mm. The biceps groove at the level of the articular surface has a constant relation to the version of a prosthetic articular surface in relation to the fins of the prosthetic body. If the anterior fin is placed at the biceps groove, the articular segment will be in 30° of retroversion. If the posterior fin is placed 8 mm posterior to the biceps groove, the same degree of retroversion will be recreated.

Injury to the blood supply of the proximal humerus has been implicated in the development of avascular necrosis (AVN).[5] The ascending branch of the anterior circumflex humeral artery (artery of Liang) has been demonstrated by Gerber to provide most of the blood flow to the articular segment. If the medial calcar of the humerus is spared by the fracture, the vessel will be spared.

Rotator cuff

The rotator cuff is the critical structure that must be reconstructed following proximal humerus fracture. The initial fracture pattern, displacement of the fracture fragments, reduction maneuvers, and fixation techniques used to oppose the displacement forces are dependent on the rotator cuff forces that produced the fracture.[6]

The supraspinatus attaches to the greater tuberosity at the superior facet and the superior half of the middle facet. Avulsion-type forces from this muscle produce a short transverse fracture of the greater tuberosity that displaces primarily superiorly. Straight abduction helps reduce the fragment, and tension band fixation neutralizes initial displacement forces.

If the infraspinatus, which attaches to the entire middle facet of the greater tuberosity, also is involved, the fracture fragment is larger, and the fragment is displaced posterosuperiorly. In addition to a vertical tension band to neutralize displacement forces, horizontal fixation helps neutralize rotational forces from the infraspinatus.

The subscapularis inserts onto the lesser tuberosity. These fractures avulse the lesser tuberosity anteromedially. Horizontal fixation best neutralizes these fractures. In four-part fractures, the tuberosities are displaced, and the supportive structures of the articular segment are removed. Therefore, this fragment tilts superiorly and subsides. If the forces then axially load the shaft against this head segment, it can extrude laterally, disrupting the medial calcar and its blood supply.

Neurovascular supply

Some 21-36% of proximal humerus fractures are associated with neurovascular injuries; 8% result in permanent motor loss. The axillary nerve is the nerve most commonly injured. The fracture pattern most commonly associated with axillary nerve injury is an anterior fracture dislocation with a displaced greater tuberosity. Loss of sensation over the lateral deltoid should alert the examiner to possible axillary nerve injury. Isometric contraction of the deltoid should also be tested.

The suprascapular, radial, and musculocutaneous nerves also are at risk. Vascular injuries occur rarely, but 27% of axillary artery injuries may have palpable pulses due to scapular collateral circulation. Associated paresthesias and an enlarging mass must be viewed with caution. Most vascular injuries (84%) occur in patients older than 50 years; 53% are associated with brachial plexus injuries.

In attempting to reduce tuberosity fragments, it is vital to take into account the regional differences in the proximal humerus. The cortex of the proximal humerus near the greater tuberosity becomes progressively thicker distally. The exact location of the fracture line depends on the mechanism of, and energy from, the injury.

In fractures in the thinnest cortical bone, the fracture lines can be difficult to appose. These fractures are produced by low-energy forces, occur in porotic bone, and typically are comminuted. Conversely, the denser cortical bone near the biceps groove, and more distally on the shaft, provides an easier surface to approximate fracture lines. Fractures in this area are produced by high-energy forces; the fracture pattern depends on the applied force.

Indirect forces cause most shoulder fractures. The predominant force can cause predictable fracture patterns. Such injury forces are tension, axial compression, torsion, bending, and axial compression with bending. The primary fracture patterns from these forces are transverse, oblique, and spiral.

For each fracture pattern, a preferred method of fixation has been developed to resist displacement forces. Unfortunately, these patterns have not been well described in the shoulder. The orientation of the fracture pattern as a result of tension depends on the muscle-tendon unit that produced most of the displacement force. Treatment recommendations for these fractures are based on factors such as patient motivation, medical history, coexisting medical morbidities, and—the most influential factor—fracture type.

Fracture classification is being reconsidered. Neer's four-part classification, with modifications of the four-part valgus impacted type being separated from four-part fractures in which the humeral head has been extruded laterally, is used primarily to separate these fractures into treatment groups. The majority of fractures are nondisplaced, and nonoperative treatment usually is appropriate. With fracture displacement, operative intervention typically is necessary.

Operative treatment includes closed reduction with percutaneous fixation, open reduction and internal fixation (ORIF), humeral head replacement, and reverse shoulder arthroplasty.[7] Fracture patterns best suited for arthroplasty are as follows:

• Four-part fractures
• Fracture dislocations
• Head-splitting fractures
• Impaction fractures
• Humeral head fractures with involvement of more than 50% of the articular surface
• Three-part fractures in elderly patients with osteoporotic bone

However, heterogeneity of fracture patterns is observed within these groups.

The most common mechanism for proximal humerus fractures is a fall on an outstretched hand from a standing height. In younger patients, high-energy trauma is a more frequent cause, and the resultant injury is more devastating. Additional mechanisms include violent muscle contractions from seizure activity, electrical shock, and athletic injuries. Finally, a direct blow to the proximal humerus may also lead to fracture.

A conservative estimate is that proximal humerus fractures account for approximately 5% of all fractures. These fractures occur primarily in older patients, many of whom are osteoporotic. Like hip fractures, proximal humerus fractures are a major cause of morbidity in the elderly population. As the population base ages, the incidence of these fractures will continue to increase.

The overall prognosis for proximal humerus fractures depends on numerous factors, including the following:

• Fracture pattern (Neer or Orthopaedic Trauma Association [OTA] type)
• Patient age
• Overall health status of patient (associated comorbidities)
• Patient's expectations
• Willingness of the patient to undergo lengthy rehabilitation
• Ability to anatomically reduce the tuberosities in surgically managed fractures
• Presence or absence of inferomedial support

These fractures as a whole require at least 1 year for recovery.

Yang et al reported functional outcomes following treatment with a proximal humerus locking plate in 64 patients followed for more than 1 year.[8]  They divided the study population into two groups according to the presence or absence of inferomedial mechanical support of the humeral head segment.

The authors noted no differences between groups with regard to age, sex, mechanism of injury, or fracture pattern (Neer or OTA).[8]  They observed higher Constant-Murley subscores in strength and range of motion in patients with preserved inferomedial support. No difference was noted in pain or activities of daily living portions of the score. They determined that both the presence of an intact medial support and age were independent predictors of functional outcome.

Furthermore, Yang et al noted fracture union in all cases with a mean neck-shaft angle of 126.5° (range, 101-143°).[8]  Radiographic differences between those with and without medial support were not reported. Finally, they observed three instances of tuberosity malunion. All occurred in patients older than 65 years with osteopenia and were associated with poor results. The most frequent complication was screw penetration after fracture collapse and loss of reduction. This necessitated screw removal in five of 64 patients.

A randomized controlled trial evaluated the 2-year outcome of locking plate fixation versus nonoperative treatment in elderly patients treated for a displaced three-part fracture of the proximal humerus. The findings report that while treatment with a locking plate resulted in superior functional outcome and health-related quality of life compared with nonoperative treatment, 30% of the patients studied required additional surgery because of fracture complication.[9]

It is important to note that whereas the Constant score, the DASH (Disabilities of the Arm, Shoulder, and Hand) score, and the EQ-5D (EuroQol Group; Rotterdam, Netherlands) score noted in the study were all in favor of the locking plate group on all follow-up occasions, this favorable tendency did not reach statistical significance.[9]

Hatzidakis et al studied the outcomes of 38 patients who were treated with locked angular-stable intramedullary nail fixation for acute two-part surgical-neck fractures at a minimum 12-month follow-up.[10]  All fractures healed primarily. The mean Constant score was 71, which was a mean age-adjusted Constant score of 97%. The average forward elevation was 132°. The average Constant pain score was 13 (15 = no pain). In all, 37 (97%) of 38 patients were satisfied with the results. Four patients (11%) required a reoperation.

Südkamp et al evaluated the complication rate and functional outcome of 187 patients after ORIF of proximal humerus fractures using a locking proximal humerus plate.[11]  At 12-month follow-up, the average Constant score was 70.6, which was 85% of the score for the contralateral side. The average active elevation was 132°, and external rotation was 45°. The overall complication rate was 34% (52/155), and the most common complication (21/155) was intraoperative screw penetration of the humeral head. Twenty-nine patients (19%) required a reoperation.

Bahrs et al assessed the Constant score and radiographic outcome in 66 patients with minimally displaced and/or impacted fractures of the proximal humerus treated with early immobilization.[12]  All of the fractures healed well, without nonunion. In 80% of patients, radiologic assessment showed fracture-displacement of less than 15º angulation and/or less than 5 mm of displacement of the greater tuberosity.

In this study, there was a significant association between the final Constant score and age, American Society of Anesthesiologists (ASA) classification, AO classification, and initial fracture displacement.[12]  The authors concluded that early physiotherapy with a short period of immobilization is sufficient management for minimally displaced and/or impacted fractures of the proximal humerus.

Lenarz et al reviewed 30 patients who underwent reverse shoulder arthroplasty for displaced three- and four-part fractures (mean age, 77 years; follow-up, ≥12 months).[13]  The mean postoperative American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment Form score was 78, the mean forward elevation was 139°, and the mean external rotation was 27°. The complication rate was 10%. The authors concluded that reverse shoulder arthroplasty relieved pain and improved function, with a complication rate comparable to those of other treatments.

Most patients with fractures of the proximal humerus present to an acute care facility with pain following trauma. Pain and loss of function with swelling of the involved extremity are the most common symptoms on initial presentation. Document symptoms of paresthesias or weakness in the involved extremity.

Obtain a detailed history of the mechanism of injury (eg, whether the injury was the result of a direct impact to the lateral shoulder or the result of an indirect mechanism, as in a fall onto an outstretched hand). Indirect causes of proximal humerus fractures result in greater degrees of fracture displacement. Determine whether seizure or electrical shock was involved; these indirect mechanisms are associated with posterior dislocations.

Obtain the medical history, and stabilize any problems, if possible, before proceeding with operative management.

Swelling and ecchymoses usually are present about the shoulder and upper arm. Extensive ecchymosis may become visible 24-48 hours following injury. It may spread to the chest wall and flank and may involve the entire extremity. Palpate the entire upper extremity and chest wall to evaluate for associated injuries.

To determine fracture stability, gently rotate the humeral shaft while palpating the humeral head to assess whether unified motion is present. Note any movement or crepitus. In high-energy injuries, inspect the skin closely for any disruptions that may allow fracture contamination (ie, open wounds). Pulsatile or expanding hematomas may indicate a vascular lesion.

It is essential to determine the presence of any associated neurovascular injury. The axillary nerve is the nerve most commonly injured in proximal humerus fracture. Carefully assess sensation over the deltoid muscle and isometric deltoid motor function. Additionally, perform distal neurologic testing for brachial plexus injuries.

Examination of peripheral pulses is helpful, but it does not exclude axillary disruption, because distal pulses may be intact because of collateral circulation around the scapula. Inspect the proximal shoulder girdle for an expanding mass, which may be the only sign of arterial rupture. If vascular injury is suspected, obtain an angiogram and a vascular surgery consultation immediately.

Evaluate associated injuries (eg, pneumothorax, other traumatized areas) with radiographic studies (see Workup). Radiographic examination of the shoulder should include Neer's trauma series, which consists of a true anteroposterior (AP) view of the glenohumeral joint, a Y-view, and an axillary view. Modifications of the axillary view, such as a Velpeau view or computed tomography (CT) scan, can be obtained to evaluate the relation of the humeral head to the glenoid. It is estimated that the initial treating physician nevertheless misses 50% of all fracture-dislocations.

Routine preoperative laboratory studies for proximal humerus fractures include the following:

• Complete blood count (CBC)
• Basic metabolic panel
• Coagulation studies
• Type and cross-match

Radiographic evaluation is the most important diagnostic tool for proximal humerus fractures. Incorrect views or poor quality radiographs can lead to errors in prognosticating outcome and an inappropriate choice of treatment.

The initial series for evaluating a patient with a suspected proximal humerus fracture is the trauma series, which consists of anteroposterior (AP) and lateral views in the scapular plane and an axillary view.

The scapula sits obliquely to the chest wall. Therefore, to achieve a true AP view, the x-ray beam must be tilted approximately 40° to plane of the thorax. Similarly, in the lateral view, the x-ray beam will parallel the scapular spine when the body is tilted 40°. The axillary view can be obtained with the use of the Velpeau view, allowing the arm to stay within the sling. In this view, the patient is seated and tilted backwards approximately 45°.

Use the AP projection to assess fracture displacements of the surgical neck (varus or valgus), the greater tuberosity (superior displacement), and the lesser tuberosity (medial displacement). The glenohumeral joint should be clearly visible. If overlap is seen, suspect dislocation. The lateral view is helpful in assessing flexion or extension of the surgical neck and posterior displacement of the greater tuberosity fragment.

The axillary view helps to assess tuberosity fragments, with anteromedial displacement of the lesser tuberosity fragment and posterior displacement of the greater tuberosity fragment. This view is critical in assessing the greater tuberosity fragment, as superior displacement may be absent and the infraspinatus can be completely avulsed with a posteriorly displaced fragment. Furthermore, dislocation of the head can be defined clearly on this view.

Linear tomography can help to assess nonunions of the surgical neck. However, it has been supplanted by computed tomography (CT). In addition to surgical-neck assessment, CT can provide information on articular involvement in head-splitting fractures, impression fractures, chronic fracture-dislocations, and glenoid rim fractures.[14] Tuberosity displacement can also be assessed.

Diagnostic evaluation of proximal humerus fractures is critical in assessing treatment choices. Initially, plain radiographs of good quality that include Neer's trauma series are used to define the extent of injury. These fractures can be classified with the Neer or AO/ASIF (Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation) classification systems. Each of these methods has certain advantages, but they also share some common problems.

Because both classification systems have limited reliability, reproducibility among observers, and consistency in findings by the same observer at different times, the initial radiographs cannot be relied upon entirely to make a treatment decision. Even if computed tomography (CT) scans and three-dimensional (3D) images are added, reliability and reproducibility are limited. However, an understanding of fracture type gives the physician essential information on prognosis and treatment options.

The Neer classification system is based on displacement criteria of 1 cm or fragment angulation of 45°. The type of fracture then is divided into the following four segments:

• Articular segment
• Lesser tuberosity
• Greater tuberosity
• Surgical neck

The basis for the AO/ASIF classification is predicated on disruption of the blood supply to the articular segment, thereby increasing the likelihood of avascular necrosis (AVN). These fractures are deemed least ideally suited for internal fixation.

The treatment objective in proximal humerus fractures is to allow bone and soft-tissue healing that maximizes function of the upper extremity while minimizing risk. Displaced fractures, if left untreated, have the greatest likelihood of limited functional outcomes. Most fractures are extra-articular and are minimally displaced; these fractures may be treated with supportive treatment only. Persons with stable fractures can begin rehabilitation early and typically have superior functional outcomes.

Indications for treatment are displaced articular fractures and periarticular fractures. However, the "personality" of the fracture (eg, bone quality, fracture orientation, concomitant soft-tissue injuries), the personality of the patient (eg, compliance, realistic attitude, mental status), and the personality of the surgeon (eg, surgical experience, technical familiarity, available resources) all have a tremendous effect on specific treatment indications.

The most common definition of displacement is 1 cm or more between fracture fragments or 45° of angulation or more between fragments. The segments that most commonly produce these fragments are the humeral articular surface, the greater and lesser tuberosities, and the surgical neck. Currently, a greater tuberosity that is displaced 5 mm or more is commonly considered a fragment that should be reduced.

Contraindications for repair of proximal humerus fractures include inability to tolerate the procedure medically and lack of clearance for surgery through the primary care physician or specialty consultants (ie, cardiologist, vascular specialist).

In the future, advances in imaging will enhance the accuracy of classification of proximal humerus fractures. This, in turn, will improve the selection of patients best suited for operative intervention and will allow better comparison of different treatments.

Improved use of limited internal fixation with percutaneous fixation, with or without growth factors to help accelerate healing, also will produce more reliable outcomes with less morbidity. The use of reverse shoulder arthroplasty will likely continue to expand,[15, 16] yielding better functional outcomes with consistent pain relief.

Finally, ideal rehabilitation for fractures treated operatively or nonoperatively will minimize time for functional recovery following these injuries.

Proximal humerus fractures may be treated nonoperatively with an initial period of immobilization followed by early motion. Initial immobilization may be achieved with a sling, a shoulder immobilizer, or a sling with an accompanying swathe. These devices provide varying degrees of constraint. Depending on the fracture type and the patient's body habitus, each of these devices may be helpful. Additionally, because the patient's axilla will be apposed for a prolonged period, a simple pad may be placed in the axilla to minimize skin chafing.[14]

If the fracture is stable, gentle range-of-motion (ROM) exercises may begin after 7-10 days. However, an unstable fracture may lead to early fracture displacement. In general, unstable fractures are much more painful and often require surgical stabilization to achieve adequate pain relief.

Physical therapy may be initiated after 3 weeks and may allow a more expeditious return of upper-extremity function. However, aggressive passive and active-assisted ROM must not be performed until bony union has occurred.[17]

One study evaluated the outcome of conservatively treated proximal humeral fractures. Using data measured according to the Constant score, quality of life assessed using EuroQol-5D, and fracture pattern analyzed with radiography and CT in 70 consecutive patients aged 60-85 years, the study noted that all fractures consolidated uneventfully with no loss of reduction in either group.[18]

In this study, the worst functionality results were recorded in four-part fractures (33.66), three-part fractures (54.64), and two-part fractures (65.88 and 71). Patients older than 75 years scored lower than those younger than 75 years; however, no difference was noted in quality-of-life perception. These results suggest that conservative treatment of proximal humerus fractures in patients older than 75 years provides good pain relief with limited functional outcome.[18]

Another study evaluated the long-term outcomes of nonoperatively treated proximal humerus fractures. In 650 patients with a mean age of 65 years and a mean follow-up period of 45.7 months, the study noted high rates of radiographic healing, good functional outcomes, and a modest complication rate.[19]

Surgical management of proximal humerus fractures may be categorized either according to fracture type (eg, Neer type, anatomic type, greater tuberosity, surgical neck, anatomic neck, articular surface, or lesser tuberosity fragments) or according to method of fixation (eg, closed reduction with no fixation, percutaneous fixation, open reduction with internal fixation [ORIF], or humeral head replacement associated with tuberosity fixation).[20, 21]

Two-part fractures

Greater tuberosity

Displacement of greater-tuberosity fractures usually is posterior and superior. Attempts at closed reduction typically are unsuccessful, except in cases with an associated anterior dislocation, in which closed reduction of the fragment may be adequate.

However, close scrutiny of the lateral Y-view and the axillary view are needed to avoid persistent posterior displacement that can heal in a malunited position and lead to a mechanical block of motion. Up to 8% of greater-tuberosity fractures are associated with an anterior dislocation; these fractures have the highest incidence of axillary nerve injury.

To optimize shoulder function, open treatment is recommended for greater-tuberosity fractures displaced 5 mm or more. The type of greater-tuberosity fracture influences surgical approach and fixation. Fragment sizes may range from small to large. A small fragment that is displaced primarily superiorly is a result of an avulsion of the supraspinatus. This fracture is approached anterosuperiorly, much like a rotator cuff repair, complete with an acromioplasty.

An alternative approach is a deltoid-splitting approach,[22] but instead of the deltoid being taken off the anterior acromion,[23] it is peeled off the posterior acromion; this avoids the acromioplasty and minimizes weakening of the anterior deltoid. This approach is especially helpful if the fragment is displaced posteriorly. Fixation of smaller fractures can be accomplished with heavy sutures, wire, or, occasionally, screws. Associated rotator cuff tears should be closed.

Larger fractures with a spiral or oblique configuration can extend several centimeters into metaphyseal bone. A deltopectoral approach provides adequate exposure for reduction and proper fixation, which may require a distal exposure for drill holes for sutures or wires. The axillary nerve is in danger if a deltoid-splitting approach is used for this type of fracture pattern. Fixation with heavy suture, wire, and, possibly, screws may be considered for these fractures.

Lesser tuberosity

Displacement of the lesser tuberosity often is medial, and closed reduction with internal rotation often can place the tuberosity in satisfactory position. Therefore, open treatment of these fractures may not be necessary. However, posterior dislocation can result and should be suspected in the isolated lesser-tuberosity fracture.

For the unstable shoulder following posterior dislocation, with the arm in internal rotation, use a trial of closed reduction with an external rotation brace (eg, gunslinger type of brace). Attention to reduction of the lesser tuberosity is necessary to avoid nonunion and malunion.

Occasionally, a reverse Hill-Sachs lesion of the humeral head may be present. If less than 40% of the head is involved and the shoulder is unstable with closed reduction, advancement of the lesser tuberosity into the head defect can be performed (McLaughlin procedure). Therefore, CT may be helpful for assessing humeral head involvement in lesser-tuberosity fractures.

Surgical neck

Displacement of surgical-neck fractures typically produces an angulation with an anterior apex and medial displacement of the shaft due to the pull of the pectoralis major. Reduction maneuvers include flexing and adducting the arm to relax the displacement forces. Occasionally, interposition of the long head of the biceps can block reduction.

In cases where closed reduction can be accomplished, treatment options include closed reduction alone (if reduction is stable), percutaneous fixation, and ORIF. Closed reduction alone under general anesthesia offers limited morbidity, but it may allow gradual loss of reduction, leading to malunion that will produce motion loss to a minimum of 1° per 1° of deformity. For example, a 45° anterior angulation produces a 45° loss of anterior flexion.

Percutaneous pinning has been advocated with the use of 2.5-mm terminally threaded AO/ASIF pins. This technique can be challenging technically; in osteoporotic bone, it may have associated hardware problems. Frequent reoperations may be necessary for pin removal.

ORIF for surgical-neck fractures in which closed reduction can be accomplished has the potential for increased operative morbidity when compared to the above-described closed techniques. However, this procedure may provide a more stable construct, allowing a more dependable functional outcome.

Methods of limited ORIF using intramedullary devices have been described.[10, 24, 25, 26] A variety of devices have been used with this technique. In cases where closed reduction cannot be accomplished, an open deltopectoral approach allows a safe approach to the fracture. The authors’ preferred technique is an open reduction through the deltopectoral approach using a precontoured proximal humerus locking plate for fixation.

The use of precontoured proximal humerus locked plates has yielded excellent results, with enhanced fixation in osteoporotic bone. Fixation may also be enhanced with maintenance of reduction with the use of intramedullary allograft or calcium phosphate cement. Locked intramedullary nail fixation of surgical-neck fractures has also shown promising results.[27]

The ProFHER (PROximal Fracture of the Humerus: Evaluation by Randomisation) trial assessed the clinical effectiveness and cost-effectiveness of surgical treatment against those of nonsurgical treatment in 250 adults with a displaced fracture of the proximal humerus involving the surgical neck (18 one-part, 128 two-part, and 104 three- or four-part).[28, 29] The authors found that surgical treatment did not result in a better outcome for most patients with such fractures and was not cost-effective in the United Kingdom setting.

Anatomic head

This rare injury can occur in conjunction with humeral head dislocation. In general, it has a very guarded prognosis because of the compromised blood supply to the head segment. ORIF can be difficult because of the limited bone available for fixation devices to be placed. Wire or suture tension band techniques have been utilized with attention to meticulous handling of soft tissue.

Primary humeral head replacement also is performed for anatomic head fractures. This can be attractive, in that the tuberosities can be left intact, and soft-tissue management is straightforward because contracture or scar has not developed. Additionally, if the metaphyseal bone stock is maintained, uncemented placement of the stem may be reasonable.

Three-part fractures

Three-part proximal humerus fractures usually are rotary fracture-dislocations in which one tuberosity is displaced and retracted by its attached rotator cuff musculature. The humeral head and the other tuberosity remain attached and are subluxated or dislocated, rotating according to the pull of the attached rotator cuff. Blood supply to the head may be preserved by the retained soft-tissue attachments. However, the risk of AVN remains approximately 14%. These fractures nearly always require open surgical management.

Preoperative planning should include a complete history and physical examination with a thorough neurovascular examination of the affected extremity. If vascular injury is suspected, obtain an angiogram and vascular surgery consultation immediately. Document any neurologic deficits.

Radiographic studies should include anteroposterior (AP), lateral, and axillary views, as well as CT of the affected shoulder. Routine preoperative laboratory studies should be obtained (complete blood count, basic metabolic panel, coagulation studies, and type and cross-match). Obtain appropriate consultations prior to surgery.

Elderly patients with poor tissue quality and osteoporosis usually require arthroplasty. Because of the difficulty of reliable tuberosity healing, which is necessary for proper rotator cuff function, reverse shoulder arthroplasty (see Operative Details) has been gaining popularity for the treatment of these fractures[30] and is the authors’ preferred method for treating three- and four-part fractures in elderly individuals.

Sebastiá-Forcada et al, in a study of 62 elderly patients (>70 y) with complex proximal humeral fractures, compared the outcomes of reverse shoulder arthroplasty (n = 31) with those of hemiarthroplasty (n = 31).[31]  They found that reverse shoulder arthroplasty resulted in less pain, better function, and a lower revision rate. Revision from hemiarthroplasty to reverse shoulder arthroplasty did not yield significant improvement in outcomes.

Ross et al studied survival and clinical and radiologic outcomes of reverse shoulder arthroplasty performed to treat three-part and four-part proximal humeral fractures in 21 shoulders in 20 elderly patients (average age, 79 y).[32]  They reported grade 1 scapular notching in four shoulders; a scapular spur in seven; class 1 heterotopic ossification in four; nonprogressive lucent lines in two; nonprogressive radiolucency around the superior screw in three; and an axillary nerve palsy in one (which resolved spontaneously by 12 months after surgery).

Shannon et al evaluated outcomes in 44 elderly patients treated for proximal humerus fractures who underwent either primary reverse total shoulder arthroplasty (n = 18) or salvage reverse total shoulder arthroplasty after failed osteosynthesis (n = 26).[33] ​ They found that whereas the latter was associated with a higher rate of complications than the former, revision and reoperation rates were comparable for the two approaches, as were clinical outcomes and shoulder function.

Luciani et al retrospectively evaluated long-term (5-y) clinical and radiologic outcomes of reverse shoulder arthroplasty with and without tuberosity grafting in 55 elderly (≥65 y) patients with three- or four-part proximal humerus fractures.[34] Reverse shoulder arthroplasty yielded satisfactory results even at 5-year follow-up. Preservation of the tuberosities in anatomic position improved active forward elevation and external rotation, as well as enhanced patient satisfaction with fewer complications.

In a prospective randomized controlled trial (N = 59) that directly compared reverse shoulder arthroplasty (n = 29) with nonoperative treatment (n = 30) for three- or four-part proximal humerus fractures in elderly patients, Lopiz et al found only minimal benefits for reverse shoulder arthroplasty over nonoperative treatment of these fractures.[35] At short-term (12-mo) follow-up, reduced pain perception appeared to be the main advantage of reverse shoulder arthroplasty.

When selecting a reverse shoulder arthroplasty prosthesis, the surgeon should consider factors that lead to improved tuberosity healing. Among the factors the authors believe are most important are the following:

• Monoblock construction
• Proximal porous coating around the humeral socket
• Anatomic neck-shaft angle of 135°

In younger patients, every effort should be made to retain the humeral head. Informed consent forms should include the possibility of hemiarthroplasty or reverse shoulder arthroplasty in case the decision is made intraoperatively that fixation is an inappropriate treatment.[13, 36]

Prior to surgery, fully inform patients of the intensive postoperative rehabilitation required, the possibility of residual stiffness, and the possibility of reoperation (for removal of painful hardware, for capsular release and lysis of adhesions, for treatment of nonunion, and for possible conversion to hemiarthroplasty or total shoulder arthroplasty should AVN or posttraumatic arthritis occur).

Four-part fractures

Four-part fractures have detachment of both tuberosities and dislocation of the humeral head from the glenoid. The tuberosities are retracted in the direction of the pull of their respective rotator cuff musculature.

No viable soft-tissue attachments remain to the humeral head, rendering it avascular. The incidence of AVN is approximately 34%. These fractures all require open surgical management if a viable shoulder is to be obtained.

Preoperative preparation is the same as described for three-part fractures and includes a complete history and a meticulous physical examination, with close attention paid to neurovascular examination of the affected extremity. Radiographic evaluation should include AP, lateral, and axillary views, along with CT. Obtain appropriate laboratory studies and specialty consultations prior to surgery.

Results are best if surgery is performed within 2 weeks of injury. Longer delays result in retraction of the tuberosities with concomitant atrophy of cuff musculature, thereby compromising outcome.

Open reduction and internal fixation

The patient with a proximal humerus fracture is placed in the beach-chair position. Fluoroscopy is placed, and scout images are obtained before preparing and draping. Take care throughout the surgery not to apply excessive traction to the affected extremity; this can injure the brachial plexus. Intravenous (IV) antibiotics are administered prior to skin incision. Additionally, place proper padding where necessary to avoid compression of neurovascular structures (eg, by straps).

A deltopectoral approach is used. The authors preserve the cephalic vein and retract it medially with the pectoralis major following coagulation and division of the perforating veins from the deltoid. This is done to avoid damaging the vein during placement of retractors under the deltoid during operation. The clavipectoral fascia is divided, and the subacromial, subdeltoid, and subcoracoid spaces are carefully developed. The conjoint tendon only should be retracted medially to avoid injury to the musculocutaneous nerve.

The axillary nerve then is localized in the subdeltoid and subcoracoid spaces by gently sweeping the finger in a proximal-to-distal fashion. Its position is confirmed by gently tugging on it in the subcoracoid space while palpating it in the subdeltoid space and vice versa. Intermittently apply this test throughout the operation to detect accidental fixation or entrapment of the nerve.

The long head of the biceps tendon is localized distally under the insertion of the pectoralis major and followed proximally to locate the rotator interval, which then is opened. Care is taken to avoid excessive soft-tissue stripping so as to maintain the blood supply of the humeral head, particularly the arcuate branch of the anterior humeral circumflex artery.

The displaced tuberosity is identified, and two No. 5 nonabsorbable sutures are placed at the bone-tendon junction. These are used to apply traction and fixation of the fragment. Any adhesions are carefully lysed to mobilize the tuberosity. Bone quality, comminution, and fracture stability must be assessed to determine the need for supplemental intramedullary support with allograft or calcium phosphate cement.

The head and its attached tuberosity then are reduced and fixed with the instrumentation of choice. The authors prefer the use of a precontoured, periarticular locking plate. Surgeons should avoid excessive soft-tissue stripping to preserve the blood supply to the articular segment.

Obtain fluoroscopic images at this time to ensure proper reduction. The displaced tuberosity then is reduced and fixed with a combination of cerclage sutures and figure-eight sutures attached to the plate. Obtain fluoroscopic images during tuberosity fixation to avoid overreduction or underreduction. ROM that does not derange stability is documented intraoperatively. The operative site then is irrigated abundantly, and standard closure is performed. The authors rarely find drains necessary.

An immobilizer is applied to the extremity in the operating room. A thorough neurovascular examination is performed in the recovery room. Direct particular attention to examination of the axillary and musculocutaneous nerves. Document any deficits immediately. The patient generally is hospitalized 2-3 days postoperatively. Prophylactic IV antibiotics are administered for 24 hours.

The authors protect the extremity in a shoulder immobilizer for 3-4 weeks, during which time passive exercises are instituted in accordance with the stable ROM noted intraoperatively. The immobilizer then is replaced with a sling for an additional 2-3 weeks, and active ROM is instituted progressively. If intraoperative stability is considered tenuous, the authors may elect to use an abduction pillow and allow minimal ROM for up to 6 weeks while fracture healing is obtained.

The patient is monitored in the clinic via serial radiographs at 10 days, 3 weeks, 6 weeks, 3 months, and 6 months, then as needed thereafter.

If hardware causes impingement or pain, it may be removed once fracture healing is complete. Stiffness may necessitate operative capsular release. Nonunions usually necessitate reoperation with osteotomy, bone grafting, and possible conversion to reverse shoulder arthroplasty. AVN may necessitate conversion to total shoulder arthroplasty.

Minimally invasive lateral approach

A minimally invasive lateral subacromial approach to ORIF has been described. In a retrospective analysis, Liu et al compared this approach with the conventional deltopectoral approach in 91 patients followed for 2 years.[37]  They concluded that the minimally invasive lateral approach was preferable for treating Neer type 2 and 3 proximal humerus fractures.

Reverse shoulder arthroplasty

The patient with a proximal humerus fracture is placed in the beach-chair position. Fluoroscopy is placed, and scout images are obtained prior to preparing and draping. Take care throughout the surgery not to apply excessive traction to the affected extremity; this can injure the brachial plexus. IV antibiotics are administered prior to skin incision. Additionally, place proper padding where necessary to avoid compression of neurovascular structures (eg, by straps).

A deltopectoral approach is used. The authors preserve the cephalic vein and retract it medially with the pectoralis major following coagulation and division of the perforating veins from the deltoid. This is done to avoid damaging the vein during placement of retractors under the deltoid during operation. The clavipectoral fascia is divided, and the subacromial, subdeltoid, and subcoracoid spaces are carefully developed. The conjoint tendon only should be retracted medially to avoid injury to the musculocutaneous nerve.

The axillary nerve then is localized in the subdeltoid and subcoracoid spaces by gently sweeping the finger in a proximal-to-distal fashion. Its position is confirmed by gently tugging on it in the subcoracoid space while palpating it in the subdeltoid space and vice versa. Intermittently apply this test throughout the operation to detect accidental fixation or entrapment of the nerve.

The long head of the biceps tendon is localized distally under the insertion of the pectoralis major and followed proximally to locate the rotator interval, which then is opened. The displaced tuberosities are then identified.

Five No. 5 nonabsorbable sutures are placed at the bone-tendon junction of the greater tuberosity, and two No. 5 nonabsorbable sutures are placed in the bone-tendon junction of the lesser tuberosity. These are used to apply traction and fixation of the fragments. Any adhesions are carefully lysed to mobilize the tuberosities. The humeral head is then removed and saved for supplemental autograft.

Attention is then turned to the glenoid. A circumferential capsulectomy is performed. The glenoid is then reamed and prepared in standard fashion. Glenosphere size is determined by the humeral head fragment removed. Typically, this is 32 minus 4 for women and 32 neutral for men in the system used by the authors. Glenoid preparation is typically straightforward and often easier than with standard reverse shoulder arthroplasty, as the humeral head is removed and the tuberosities are mobilized.

The humerus is then prepared. The canal is sequentially reamed until diaphyseal chatter is obtained. A trial broach is placed, typically two sizes smaller than the largest diaphyseal reamer. One must ensure proper retroversion of the broach using a 30° guide in line with the forearm. The lateral fin of the broach is marked with electrocautery to ensure proper retroversion of the prosthesis. The broach is then removed.

Two drill holes are placed in the proximal humerus shaft, and No. 5 nonabsorbable sutures are placed through the drill holes for later vertical repair of tuberosities.

The five sutures previously placed through the bone-tendon junction of the greater tuberosity are then placed through a suture hole on the monoblock humeral prosthesis. A cement restrictor is placed. A cement gun is then used to place antibiotic-impregnated cement dyed with methylene blue into the humeral canal, with the cement in a runny state. (Some, however, have found no significant differences in postoperative ROM, functional outcomes, complications, or revisions between cemented and uncemented reverse shoulder arthroplasties for proximal humerus fractures.[38] )

The humeral component is inserted, with care taken to ensure proper version from the previously marked lateral fin. Excess cement is removed. A cancellous bone graft is placed around the proximal porous coating of the prosthesis to promote tuberosity healing. Cement is allowed to harden. The shoulder is then reduced.

The sutures previously placed through humeral drill holes are placed, one through the bone-tendon junction of the greater tuberosity and one through the bone-tendon junction of the lesser tuberosity. Five sutures previously placed through the bone-tendon junction of the greater tuberosity and prosthesis are passed anterior through the bone-tendon junction of the lesser tuberosity for cerclage fixation of the tuberosities. These sutures are then tied first to prevent overreduction of the tuberosities to the shaft. The vertical sutures are then tied.

Fluoroscopy images are then obtained to ensure no cement extrusion from the canal and to confirm adequate tuberosity reduction. The wound is then closed in layers in standard fashion. The authors do not routinely use Hemovac drains.

An immobilizer is applied to the extremity in the operating room. A thorough neurovascular examination is performed in the recovery room. Direct particular attention to examination of the axillary and musculocutaneous nerves. Document any deficits immediately. The patient generally is hospitalized 2-3 days postoperatively. Prophylactic IV antibiotics are administered for 24 hours.

The authors protect the extremity in a shoulder immobilizer for 6 weeks, during which time pendulum exercises are instituted, with elbow, wrist, and hand ROM therapy. At that point, the immobilizer is discontinued, and self-directed therapy with active assisted ROM is begun. The patient is monitored in the clinic via serial radiographs at 10 days, 6 weeks, 3 months, 6 months, and 1 year, then yearly thereafter.

Neurologic and brachial plexus injuries

Neurologic and brachial plexus injuries occur in as many as 50% of proximal humerus fractures. Anterior fracture dislocations may injure the axillary nerve. Carefully document any deficits, and monitor them via electromyography. Explore injuries showing no improvement at 3 months. The risk of nerve injury is increased in elderly patients, fractures at the surgical neck, dislocation, blunt trauma with associated hematoma, and failed ORIF.

Vascular injuries

Injury to the axillary artery may occur in displaced proximal humerus fractures, usually following severe blunt trauma or penetrating trauma. This injury may also be seen with minimally displaced fractures in the elderly patient with arteriosclerosis due to lack of elasticity of the vessel walls. Although it is always important to evaluate the radial pulse, its presence in a case of vascular injury can be misleading because of collateral circulation.

Maintain a high index of suspicion, and proceed to an angiogram when signs of vascular compromise are present. These include expanding hematoma, pallor, paresthesias, pulselessness, unexplained hypotension, bruits, and pulsatile external bleeding. Perform emergency arterial repair when indicated. Failure to recognize and treat these injuries can have catastrophic consequences, including amputation, gangrene, and neurologic compromise (due to compression from the hematoma).

Stiffness or frozen shoulder

Stiffness or frozen shoulder may occur with nonoperative and operative management of proximal humerus fractures. This emphasizes the need for a directed physiotherapy program to maintain mobility during the postfracture and postoperative period. Patients who do not respond to stretching exercises may require operative management, including arthroscopic and/or open release of adhesions. Manipulation under anesthesia should not be performed alone, as risk of refracture exists.

Avascular necrosis

AVN is seen in as many as 14% of three-part fractures treated with closed reduction and in as many as 34% of four-part fractures. This complication leads to pain and stiffness in the shoulder and may ultimately necessitate total shoulder arthroplasty.

Malunions

Greater-tuberosity malunions occur as a result of the pull of the rotator cuff. Displacement is superior if only the supraspinatus is involved. Union at this site may result in impingement syndrome. Displacement is posterior if the pull is predominately infraspinatus. Union at this site may result in posterior impingement against the glenoid, resulting in decreased external rotation.

Indications for surgery include pain and loss of function. Superior-tuberosity malunion may be treated with acromioplasty, if it is not severe, or with tuberosity osteotomy and cuff mobilization. Acromioplasty offers no benefit in posterior malunions, which are treated by means of tuberosity osteotomy and capsular release. Isolated lesser-tuberosity malunions are very rare and will not be discussed here.

Surgical-neck malunions and malunions of three-part fractures may be multiplanar in nature with combinations of rotation, flexion/extension, and varus/valgus deformities. Significant angulation may be accepted at the surgical neck. However, there is a concomitant loss of elevation. Additionally, varus malunion places the greater tuberosity in the subacromial space with loss of lateral humeral offset.

Malunion and AVN of the humeral head in three- and four-part fractures usually necessitate prosthetic replacement. Frequently, posttraumatic arthritis is present on the glenoid surface, and a glenoid component also should be used.

Malunion of a fracture-dislocation may be difficult to treat. The head component may be dislocated anteriorly or posteriorly. Great care must be taken in its mobilization and removal because there may be adhesion of the neurovascular bundle in the associated scar tissue. Prosthetic replacement usually is necessary.