Management of Proximal Humeral Fractures: A Review

Grayson Domingue, MD; Ian Garrison, MD; Richard Williams, MD; John T. Riehl, MD

Disclosures

Curr Orthop Pract. 2021;32(4):339-348. 

In This Article

Discussion

Anatomy

A comprehensive understanding of anatomy is required for orthopaedic practitioners to diagnose and manage PHF properly. The humeral head is retroverted 35 degrees with a head-to-neck angle of approximately 130 degrees.[9] However, the proximal humerus is highly variable between individuals. Multiple studies have demonstrated that retroversion, inclination, center of rotation, and radius of curvature are markedly variable from person to person.[10] Not only has retroversion been shown to be unique among individuals, but also between the contralateral humerus of the same individual.[10] These differences in morphology affect the biomechanics of the glenohumeral joint and can make surgical fixation and arthroplasty difficult. The proximal humerus is made up of four osseous segments: humeral head, lesser tuberosity, greater tuberosity, and humeral shaft.[11] These osseous segments, or "parts," play a vital role in Neer's classification, which is the most frequently employed classification used by orthopaedic practitioners.[12] Notably, the interplay of the surrounding muscles, ligaments, labrum, and capsule contribute greater to stability than the bone itself.[13] The contribution of these soft-tissue stabilizers is highlighted by their deficiency in pathology, such as multidirectional shoulder instability and traumatic anterior shoulder instability.

The proximal humeral ligamentous stability is primarily provided by four ligaments: coracohumeral ligament superior glenohumeral ligament, middle glenohumeral ligament, and inferior glenohumeral ligament (Figure 1). The coracohumeral ligament strengthens the rotator interval, which is a triangular space located in the anterosuperior aspect of the shoulder that contributes to stability of the glenohumeral joint.[12,14] The superior glenohumeral ligament resists inferior translation with the arm at the side (0 degrees abduction), the middle glenohumeral ligament resists anterior to posterior translation at approximately 45 degrees of abduction, and the inferior glenohumeral ligament resists anterior to posterior translation at 90 degrees of abduction.[9,14] The labrum deepens the glenoid and provides a greater contact area with the humeral head while the capsule maintains intraarticular negative pressure.[9]

Figure 1.

The anatomy of the glenohumeral joint (lateral view). Illustration by Lauren Domingue.

The proximal humeral blood supply is from the anterior and posterior humeral circumflex arteries, which are branches of the axillary artery (Figure 2). Historically, it was thought that the anterior humeral circumflex was the predominant branch to the humeral head; however, recent studies have shown that the posterior humeral circumflex has the predominant blood supply.[15] The posterior humeral circumflex provides 64% of the overall blood supply to the humeral head, and the anterior counterpart only provides approximately 36%.[15] Therefore, important care must be taken not to disrupt this vessel during the surgical approach to reduce the risk of osteonecrosis.

Figure 2.

The blood supply of the proximal humerus. Illustration by Lauren Domingue.

Deforming Forces and Biomechanics

The insertions of the rotator cuff tendons onto the proximal humerus produce predictable deforming forces with fracture (Figure 3). The teres minor, infraspinatus, and supraspinatus attach to the greater tuberosity, which can result in an abducted and externally rotated fractured segment that remains attached. This produces a posterosuperior force on the humerus. The subscapularis inserts onto the lesser tuberosity and internally rotates it and any bone fragments that remain attached to it. The pectoralis major, which adducts the proximal shaft of the humerus, applies an anteromedial force onto the humeral shaft below a PHF. Furthermore, the deltoid provides a force of abduction that can elevate the proximal fragment and provide a valgus deforming force. Recognition of these elements and their effect on fracture patterns aids in the reduction and appropriate reconstruction of PHF.

Figure 3.

The deforming forces of proximal humeral fractures (PHF). Illustration by Lauren Domingue.

Classification

PHF are most commonly classified using the Neer's classification (Figure 4). This classification is divided primarily by displacement and angulation of the four osseus segments of the humerus. A "part" is defined as an osseous segment that is displaced more than 1 cm or angulated greater than 45 degrees.[12] An important modification to Neer's original classification is that the parameters for the greater tuberosity are decreased to displacement of greater than 5 mm because studies have shown better prognostic capability utilizing 5 mm of displacement as a cutoff.[16] A Neer one-part fracture, or minimally displaced PHF, is defined as having no displaced or angulated fragments, regardless of number of fracture lines. Two-part fractures are defined as the displacement or angulation of any one osseous segment. In three-part fractures, one tuberosity is displaced with an unimpacted and displaced surgical neck component that allows for rotation about the head by the remaining attached tuberosity. Neer four-part fractures are devastating injuries with displacement or angulation of all four osseous segments.

Figure 4.

Neer's Classification of proximal humeral fractures (PHF). Illustration by Lauren Domingue.

Careful evaluation of the medial calcar may help in predicting humeral head ischemia. A short calcar segment (meaning section of the medial humeral cortex attached at the inferior margin of the humeral head segment of less than 8 mm) has been described as a predictor of humeral head ischemia (Figure 5).[17] Disruption of the medial hinge greater than 2 mm is also a highly predictive variable.[17] In addition, acute humeral head ischemia (measured by bore hole drilling or laser doppler signaling) has not been found to be predictive of later osteonecrosis.[18] Therefore, although not absolutely predictable, the potential for bony healing and viability should be considered before electing for open reduction and internal fixation (ORIF) versus arthroplasty.

Figure 5.

If there is less than 8 mm of calcar attached to the articular segment, this indicates an increased likelihood of vascular compromise. Illustration by Lauren Domingue.

Another classification commonly used in PHF is AO-Müller/Orthopaedic Trauma Association (AO/OTA) 2018.[19] AO/OTA consists of three main components: fracture location, integrity of surgical neck, and dislocation providing 13 fracture subgroups.[20] While both AO/OTA and Neer's classification are used clinically, the Neer's classification has been shown to be the more reliable and reproducible classification.[21]

Clinical Evaluation and Presentation

PHF typically are caused by direct physical trauma in the elderly patients, secondary to low-energy falls and are secondary to high-energy trauma in younger patients.[22] A comprehensive history and physical examination of the shoulder, upper extremity, and thoracic region should be performed. Relevant history that should be obtained includes the exact anatomical location of pain in the shoulder girdle, pain elsewhere in the ipsilateral arm, mechanism of injury, preinjury function, use of the upper extremity for ambulatory assistance, and hand dominance. Other relevant patient comorbidities should also be identified in the patient's history. Specifically, smoking history, diabetic status, and patient's body habitus assist the physician's decision of operative versus nonoperative management, as well as the chosen surgical modality.

A careful and thorough physical examination should be included in the diagnostic workup. Important aspects include visual inspection, palpation, neurovascular examination, and examination for concomitant neck or chest wall injuries. Patients typically present with the injured extremity held close to their chest by the contralateral hand. Key findings on visual inspection include ecchymosis about the chest, arm, and forearm; however, this may not be apparent immediately after the injury occurs. Ecchymosis involving the chest wall and flank should be differentiated from a potential thoracic wall injury. Ecchymosis seen distally in the ipsilateral extremity from the elbow to the hand is common, especially with delayed presentation and concurrent anticoagulant therapy. Other key findings include gross deformity, swelling of the affected joint and extremity, decreased range of motion (ROM), and variable crepitus. It is important to remove all constricting jewelry from the ipsilateral extremity as soon as possible after PHF.

Assessment of the patient's neurovascular status is essential, and specific attention should be paid to axillary nerve function, as it is the most common nerve injury associated with PHF.[23] A prospective study using electromyographic analysis by Visser et al.[24] found that in a population of 143 patients with displaced and nondisplaced PHF, 58% of these patients suffered axillary nerve injury. The axillary nerve is responsible for providing motor function to the deltoid via its deep branch and the teres minor via its superficial branch. The axillary nerve also provides sensory innervation to the lateral aspect of the proximal arm via the superficial lateral cutaneous nerve. Assessment of the axillary nerve should include evaluation of deltoid motor function via shoulder abduction and lateral shoulder sensation; however, testing motor function is typically not reliable secondary to pain. Resisted shoulder extension with the arm at the side can often be tolerated and can serve as a test for deltoid motor function in the acute setting. The examiner places one hand behind the patient's elbow for resistance and palpates the deltoid to feel for any muscle contraction. If motor function of the deltoid is prohibited secondary to pain during the initial evaluation, then a secondary physical examination should be performed because pain will subside either with time or analgesia. Important to differentiate from axillary nerve injury is the deltoid atony that can occur following PHF. Deltoid atony will result in loss of contour of the deltoid musculature and inferior subluxation of the humeral head seen on anteroposterior radiographs. Different from axillary nerve injury, the inferior subluxation of deltoid atony typically resolves within 3 to 4 wk after injury as function of the deltoid recovers.[25] Finally, distal pulses should be evaluated, but it should be noted that arterial injury may be masked by the extensive network of collateral circulation.[23]

Radiographic Evaluation

The purpose of the radiographic evaluation is to aid in the stratification of fractures into the Neer classification, as it can help to guide surgical management. This radiographic evaluation also should address accurately the fracture pattern, comminution, and displacement.[26] A trauma shoulder series should be obtained that includes an anteroposterior view of the shoulder, a scapular Y view, and an axillary view.[27] A true anteroposterior view of the shoulder, also known as a Grashey view, is taken in neutral rotation in the plane of the scapula and is used to assess the integrity of the glenohumeral joint. To obtain this view, the patient should be standing erect and turned 30 to 35 degrees towards the affected side. Additional radiographs that can be obtained include an apical oblique view, Velpeau view (especially useful when pain restricts the ability to obtain a standard axillary view), and a West Point axillary view. The apical oblique view is obtained by rotating the patient 30 to 45 degrees towards the affected side with the beam angled 10 to 15 degrees cephalad, allowing for visualization of anterior glenoid rim fractures as well as posterolateral humeral head depression fractures known as Hill-Sachs lesions. The Velpeau view is an alternate view for patients who are unable to tolerate positioning for an axillary view. It is obtained by leaning the patient obliquely backward 45 degrees and directing the beam caudally (Figure 6). The West Point axillary view demonstrates its benefit for identifying fractures of the anteroinferior glenoid, known as bony Bankart lesions. Additional findings on radiographs include inferior humeral head subluxation caused by blood within the joint capsule and deltoid muscular atony resulting in "pseudosubluxation."[28]

Figure 6.

Patient positioning for a Velpeau view. Illustration by Lauren Domingue.

Considering the high incidence of PHF in elderly, osteoporotic patients, inadequate screw purchase with internal fixation secondary to poor bone quality raises concern for impaired fracture healing. This may result in malunion or nonunion secondary to screw cutout and locking-plate failure. Attempts have been made to assess this risk of hardware failure by measuring the thickness of both the medial and lateral cortices of the proximal humerus. Some studies suggest that combined cortical thickness greater than 4 mm has been correlated with increased lateral plate pullout strength, which should be taken into consideration when choosing treatment modality.[29–31]

Additional studies, such as CT and MRI, are not always needed, however, they do show benefit in more complex fracture patterns and can further define fracture fragments and associated injuries. CT scan is helpful for preoperative planning, evaluating articular involvement, precisely defining fragment displacement, and addressing concern of head-split fractures.[32] MRI demonstrates its primary use in evaluating the integrity of the rotator cuff.[33]

Treatment

Options for treatment range from nonoperative management to operative interventions such as ORIF, tension banding, closed reduction and percutaneous fixation, intramedullary nailing, and arthroplasty. Treatment options are dictated by fracture pattern, degree of displacement, patient factors, and surgeon experience and comfort level with the various operative techniques.

The majority of PHF are nondisplaced or minimally displaced and can be treated nonoperatively. Many nondisplaced, minimally displaced (Neer one-part), and stable fractures can be managed nonoperatively. Other fracture types in patients with comorbidities that preclude surgery or elderly patients with low functional demands should also be considered for nonoperative treatment. Multiple recent studies have shown functional outcomes resulting from nonoperative treatment of displaced two-part surgical neck fractures in elderly populations are equivalent to surgical fixation.[34,35] Patients are immobilized in a sling and swath for 4 to 6 wk. Passive range-of-motion exercises of the elbow, forearm, wrist, and hand are begun immediately. Gentle shoulder motion can begin within the first 2 wk after fracture as well, first with supine exercises and advancing to Codman pendulum exercises. These consist of the patient standing and bending forward to allow the upper extremity to hang freely then shifting the trunk back and forth to allow the shoulder to passively swing. The patient is progressed to active-assisted exercises at 6 wk and then strengthening exercises at 3 mo. Furthermore, recent evidence suggests that even three- and four-part PHF treated nonoperatively do as well as those treated operatively with several studies showing no significant difference in outcomes between the two options.[36–38]

As noted above, the decision to treat PHF surgically versus nonsurgically will depend on many factors. Fracture characteristics as well as patient factors will play a role in decision making, and the decision ultimately will be made on an individual basis. General indications, however, for surgical treatment of PHF vary based on surgical modality of treatment. For closed reduction percutaneous pinning, patients with two-part surgical neck fractures, three-part and valgus-impacted four-part fractures in patients with good bone quality, minimal metaphyseal comminution, and intact medial calcar can be reliably managed via this route.[39,40] As for ORIF, patients with greater than 5-mm displacement of the greater tuberosity can be treated with this method.[16,29,41] Furthermore, indications for ORIF include two-, three-, and four-part fractures and head splitting fractures in younger patients.[29,41] As for intramedullary nailing (IMN), general indications include three-part greater tuberosity fractures in younger patients, surgical neck fractures, and PHF with ipsilateral humeral shaft fracture.[42,43] Lastly, indications for arthroplasty are typically broken up into hemiarthroplasty and reverse total shoulder replacement. General indications for hemiarthroplasty include complex fractures or head-splitting components in younger patients that likely will have complications with ORIF.[28,44] Indications for reverse total shoulder include nonreconstructable tuberosities and poor bone stock in low-demand elderly individuals and fracture dislocation in low-demand patients (Table 1).[29,44,45] The choice of technique for operative fixation of PHF is guided by fracture pattern, patient factors or goals, and surgeon preference. ORIF is commonly chosen when surgical treatment is indicated, and fracture morphology and patient condition allows (Figure 7). The deltopectoral and deltoid splitting approaches are two surgical approaches commonly utilized for exposure. The deltopectoral approach allows for adequate visualization of fracture fragments as well as the long head of the biceps tendon. The deltoid splitting approach is favored by some surgeons as it has been shown to have a lower incidence of humeral head necrosis and shorter operative times.[46] The lower incidence of necrosis is caused by the deltoid splitting approach providing direct access to the lateral humeral bald spot and decreasing the risk of violation of the arcuate branch of the anterior humeral circumflex artery with circumferential dissection. Nonetheless, Xie et al.,[46] demonstrated that both deltoid splitting and deltopectoral approaches had similar results in functional outcomes, total complication, visual analog scale, and hospital stay. Care must be taken in this approach to avoid the axillary nerve which runs in a posterior to anterior fashion approximately 5 cm to 7 cm distal to the anterolateral aspect of the acromion. Within 5 cm is generally considered to be the "safe zone", although the measured distance varies between studies with a reported range from 3 cm to 8 cm from the acromion.[9,47–49] Access to an anteriorly dislocated humeral head fragment from this approach can be difficult. Once reduced, fixation via open treatment is often accomplished using a precontoured anatomic plate that is designed for PHF with locking screws placed into the humeral head that create a fixed-angle construct. This resists varus deforming forces better than conventional nonlocking plates and screws.[50] Care should be taken to avoid screw penetration into the glenohumeral joint, remembering that the proximal humeral articular surface is a concave structure, therefore screws can appear to be of appropriate length on some views but can in fact be too long. Screws placed along the calcar and restoration of the calcar are crucial in providing stability to the fracture and preventing fixation failure, as is avoidance of varus malreduction.[51–53] Varus malposition has also been shown to result in inferior biomechanical function of the glenohumeral joint and result in worse clinical functional scores.[54] Tension band fixation can be used to augment other methods of fixation and in some cases can be used as a stand-alone construct. Complications requiring reoperation most commonly include shoulder stiffness, plate impingement, mechanical failure, nonunion, and osteonecrosis.[41]

Figure 7.

Preoperative anteroposterior (A) and scapular Y (B) radiograph of a two-part surgical neck proximal humeral fracture (PHF). Anteroposterior (C) and scapular Y (D) radiographs 6 mo after open reduction internal fixation.

Closed reduction and percutaneous fixation can be performed in PHF as well. This technique minimizes soft-tissue damage, which could decrease the risk of further devascularizing the already tenuously supplied proximal humerus. However, iatrogenic injury to surrounding structures such as the axillary nerve, biceps tendon, and cephalic vein remain potential hazards. This method can be more technically challenging as reduction is guided solely by fluoroscopic imaging without the advantage of direct fracture visualization. Despite its biomechanical inferiority when compared to ORIF and potential for complication, excellent results can be attained with appropriate application of this technique.[55] High rates of osteonecrosis and posttraumatic arthritis are still seen when percutaneous pinning alone is used.[40] One method employed occasionally by the senior author (JTR) consists of percutaneous pinning with terminally threaded 3-mm pins and connecting those pins to medium external fixator clamps and carbon fiber rods, creating more of a fixed-angle construct and helping to prevent pin migration and pullout (Figure 8).

Figure 8.

Preoperative anteroposterior (A) and scapular Y (B) radiograph of a displaced surgical neck proximal humeral fracture (PHF). Intraoperative anteroposterior (C) and scapular Y (D) fluoroscopic images after closed reduction percutaneous fixation with terminally threaded 3-mm pins connected to a medium external fixator (E).

IMN fixation is another minimally invasive option that can be utilized for some fracture patterns by a surgeon who is experienced with its use (Figure 9). It is most useful in surgical neck fractures in osteoporotic bone but can also be used in conjunction with supplemental ORIF or percutaneous fixation for tuberosity fractures. Care should be taken to preserve and repair the rotator cuff insertion when performing IMN treatment. In experienced hands and with modern implant improvements allowing for more tuberosity fixation options, excellent results can be achieved even in 4-part fractures.[56]

Figure 9.

Preoperative anteroposterior (A) and lateral (B) radiograph of a two-part proximal humeral fracture (PHF). Intraoperative anteroposterior (C), lateral (D), and oblique (E) fluoroscopic views following intramedullary fixation.

Hemiarthroplasty is an option for severely comminuted fractures that are not amenable to fixation, particularly those involving head splits and humeral head depression fractures in younger (nongeriatric) adult patients. Proper humeral head height is determined based off the distance between the top of the humeral head and the superior aspect of the pectoralis major tendon insertion, which averages 5.6±0.5 cm.[57] Anatomic tuberosity fixation is critical for maintaining rotator cuff function. The tuberosities are tagged with suture prior to humeral head resection, and then tied into place such that the superior aspect of the greater tuberosity lies along the anterior fin of the implant and 5 mm distal to the superior aspect of the humeral head. The lesser tuberosity tagging sutures are then used to reduce the lesser to the greater tuberosity.[58] Rotator cuff function must be intact to ensure proper joint mechanics postoperatively; therefore, tuberosity healing is an important aspect of this treatment strategy. Although implant survival is high, strength and functional results are significantly diminished when fractures to the dominant upper extremity are treated with hemiarthroplasty.[59,60]

Reverse total shoulder arthroplasty (RTSA) is an effective option when there is preinjury glenohumeral arthritis with a rotator cuff deficiency (Figure 10). In elderly patients who have severe three- and four-part fractures or dislocation, RTSA may be an excellent option especially given difficulties with tuberosity healing when performing hemiarthroplasty. Every effort should be made to preserve and repair tuberosities and rotator cuff attachment in RTSA when possible. RTSA is also a revision option when other methods of fixation fail. The original implant designed by Grammont medializes the center of rotation of the glenohumeral joint, which provides a biomechanical advantage for the deltoid muscle that allows it to compensate for deficient rotator cuff musculature.[61] However, this implant led to high rates of scapular notching and diminished external rotation. In order to compensate for this deficiency, newer implants lateralize the center of rotation compared with the Grammont prosthesis either through lateralization of the glenoid or the humeral component. Glenoid lateralization decreases scapular notching but carries a higher rate of glenoid component loosening.[62] Humeral component lateralization theoretically avoids this complication and improves mechanical function of the deltoid and remaining rotator cuff; however, sufficient clinical evidence supporting one method over the other is currently lacking.[62] Possible complications to consider include scapular notching, dislocation, periimplant fracture, and adjacent neurovascular injury. Some argue that RTSA allows for earlier mobilization and results in lower rates of reoperation in elderly populations with poor bone quality.[45] Anatomic reconstruction and healing of the tuberosities are critical for optimal outcomes.[63] Recent studies suggest that RTSA results in improved range of motion and functional results over hemiarthroplasty, and improved range of motion and functional results favor its use overall.[44]

Figure 10.

Preoperative anteroposterior (A) and scapular Y (B) radiograph of a 4-part proximal humeral fracture. Coronal (C) and sagittal (D) CT cuts demonstrating a thin head fragment and comminuted tuberosities. Anteroposterior (E) and lateral (F) radiographs 6 months after revision total shoulder arthroplasty (RTSA).

Limitations and Future Perspectives

One of the limitations implicit in a topic review such as the current review on PHF is that bias present in individual studies can lead to bias in the conclusion of the review paper. Also, a disproportionate amount of literature focusing on operative treatment is present in the literature. Additional research on nonoperative treatment of PHF could increase understanding of the injury and assist in the decision-making process.

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