Mechanism of Injury

Most proximal humerus fractures result from a fall onto an outstretched hand. This mechanism is especially common in older adults. Direct blows, such as falling onto the shoulder, are another common cause. Violent muscle contractions, such as those produced by seizures, may also fracture the humerus.

Clinical Presentation

Patients with proximal humerus fractures generally complain of diffuse shoulder pain, which may be considerable. They tend to hold the injured arm against the side and resist movement. In most cases, swelling develops early, and by the second or third day, a large ecchymosis may be apparent. The fracture site is usually point tender, but overlying structures and diffuse swelling make the fracture difficult to pinpoint during examination. Gross deformity of the shoulder and drooping of the arm are rarely caused by an isolated fracture; they suggest the presence of a dislocation.

A check of neurovascular status should be performed, including peripheral pulses and nerve function. Although it is difficult to distinguish muscle weakness caused by nerve injury from that caused by pain in the acute stages, the clinician should be on the lookout for injury to the axillary nerve (i.e., deltoid muscle weakness, decreased sensation over the mid-deltoid region). Injury to the suprascapular nerve results in weakness of the subscapularis muscle (internal rotation weakness).

Differential Diagnosis

Although the signs and symptoms of a shoulder dislocation may be similar to those of a proximal fracture, shoulder deformity or drooping is often evident in dislocations. Two views of the shoulder (anteroposterior [AP] and either a transscapular or axillary view) will confirm a dislocation by revealing that the humeral head has lost its normal relationship to the glenoid fossa ( Figure 8-3 ). A more detailed discussion of shoulder dislocations, including additional radiographic examples, is presented at the end of this chapter.

Anteroposterior ( A ) and transscapular or “Y ( B ) views showing an anterior dislocation of the humerus. On the transcapular view, note that the scapula resembles a “Y” ( dashed lines ). The humeral head should overlie the branch point of the “Y.” Note that it instead lies anterior and inferior to this point. See Figure 8-4, B , for an example of the normal positioning of the humerus.

Rotator cuff tears may also be difficult to differentiate clinically from fractures. However, radiographs of patients with rotator cuff tears are normal unless a fragment of bone was avulsed along with the tendon. Acromioclavicular (AC) separations also produce pain and decreased mobility of the shoulder, but tenderness is localized to the AC joint in these injuries.

Imaging

Shoulder Radiography

Most shoulder series include two AP views with the upper arm in internal and external rotation. These views alone are often insufficient to identify or adequately characterize proximal humerus fractures. Furthermore, patients with fractures generally resist rotation of the humerus, making it impossible to obtain two views at 90 degrees in this way. A trauma series is the preferred way to assess this region ( Figure 8-4 ). Alternatively, a standard shoulder series augmented with either a transscapular or an axillary view is often adequate to rule out significant displacement and dislocation. A computed tomography (CT) scan is recommended if the plain radiographs are difficult to interpret or to delineate the extent of displacement to aid in preoperative planning.

Trauma series of the proximal humerus. A, Anteroposterior view in the scapular plane. B, Transscapular or “Y” view. C, Axillary view.

Fracture Patterns

The majority of proximal humerus fractures are impacted and have little or no displacement or angulation. Frequently, multiple fragments are present. The most common fracture sites are the surgical neck and greater tuberosity. Lesser tuberosity fractures are uncommon, and anatomic neck fractures are rare.

Because proximal fractures may have a combination of elements, a wide variety of fracture patterns can occur. Several classification systems have been used to describe these often complicated patterns. These systems stratify fractures by risk and can be used to guide therapy.

The Neer system can be valuable in selecting fractures appropriate for primary care management. Although the parameters were selected somewhat arbitrarily, the Neer classification has withstood the test of time and is still the most widely used. It is based on accurate identification of the four major fragments of the proximal humerus and how many of these fragments are displaced. The four fragments described in the Neer classification are the greater tuberosity, lesser tuberosity, head, and shaft ( Figure 8-5 ). Most primary care providers are likely to manage only Neer one-part fractures, which include all nondisplaced proximal fractures. Regardless of the number of cleavage lines, fractures are classified as nondisplaced if no segment is displaced more than 1 cm or angulated more than 45 degrees. If all of the fracture fragments are nondisplaced, the injury is considered to be a one-part fracture because the fragments are in continuity and are held together by soft tissue. Examples of Neer one-part fractures are shown in Figures 8-6 to 8-8 .

The four parts of the proximal humerus referred to in the Neer classification: 1, greater tuberosity; 2, lesser tuberosity; 3, head; and 4, shaft.

A, Slightly impacted fracture of the surgical neck is seen ( arrow ). B, A minimally distracted greater tuberosity fragment is also apparent ( arrow ). Although three fragments are involved, this is a Neer one-part fracture because no fragment is angulated more than 45 degrees or displaced more than 1 cm.

One-part surgical neck fracture ( arrows ). A, Anteroposterior view. B, Axillary view.

(From Browner BD, Jupiter JB, Levine AM, Trafton PG [eds]. Skeletal Trauma , vol 2. Philadelphia, WB Saunders, 1992.)

Nondisplaced avulsion fracture of the greater tuberosity (Neer one-part fracture) (arrow). If the avulsed fragment had been displaced more than 1 cm, this would have been classified as a two-part fracture.

Approximately 50% of proximal humerus fractures are one-part or minimally displaced fractures. The remaining proximal humerus fractures are significantly displaced and are classified as two-part, three-part, or four-part fractures. If one fragment is displaced or angulated from the remaining intact proximal humerus according to the criteria previously stated, the injury is classified as a two-part fracture. If two fragments are individually displaced from the proximal humerus but the humeral head remains in contact with the glenoid, it is considered a three-part fracture. Four-part fractures have three or more displaced fragments combined with the humeral head dislocated from the glenoid. Familiarity with the Neer system can help the primary care provider correctly identify proximal humerus fractures and improve communication with orthopedists at the time of referral.

Indications for Orthopedic Referral

Emergency referral is indicated for open fractures and those with neurovascular compromise. Patients with fractures that involve the anatomic neck should also be referred to an orthopedic surgeon because of the high risk of AVN.

Although systematic reviews comparing nonoperative and operative treatment of displaced fractures have found insufficient evidence to determine the optimal intervention for these fractures, treatment decisions for displaced fractures (two, three, and four part) should be left to the orthopedic surgeon. If the fracture is determined to be stable by the surgeon (i.e., acceptable cortical contact between the shaft and head fragments and minimal tuberosity displacement), nonoperative treatment can lead to good outcomes.

Somewhat surprisingly, patients often tolerate proximal humerus angulation of 25 to 45 degrees with minimal adverse effect on shoulder and arm function. This is largely the result of the extreme mobility of the shoulder joint, which is able to compensate well for angulation. Patients who are athletic or very active are less likely to tolerate the angulation. For such patients, consultation may be advisable whenever angulation approaches or exceeds 20 degrees. Consultation should also be considered when fractures involve the bicipital groove, because fractures in this area may interfere with proper functioning of the tendon of the long head of the biceps.

Initial Treatment

Table 8-1 summarizes management guidelines for proximal humerus fractures.

Immobilization can be achieved with either a standard shoulder sling or a collar and cuff sling ( Figure 8-9 ). Casting is not required for these fractures. The collar and cuff sling is superior for angulated fractures because the unsupported weight of the elbow may improve the degree of angulation via downward traction. A sling is preferred when disimpaction of the fragments would be undesirable such as in fractures with minimal angulation and minimal displacement. Ice and narcotic analgesics are usually required for pain relief. Patients may be more comfortable sleeping in a semirecumbent position with adequate support under the arm.

Collar and cuff sling. Note that the elbow is unsupported, producing some downward traction on the proximal humerus.

For a patient being referred to an orthopedist, a sling and swath or shoulder immobilizer can be used to stabilize the shoulder until the patient can receive definitive care.

Follow-up Care

Impacted proximal humerus fractures with minimal angulation and displacement are generally very stable, and conservative treatment yields good outcomes. Healing is usually rapid owing to the large areas of impacted cancellous bone. The goal of treatment is to restore as much function as possible; thus, mobilization is begun as early as pain allows. In most patients, this can be done as early as 5 to 7 days after the injury. Early mobilization is associated with improved pain and mobility in the early phases and achieves results in the long term similar to those with treatment that includes longer periods of immobilization.

The patient should return for follow-up within the first week after injury. After assessment of symptoms, the importance and safety of early mobilization should be discussed. During the follow-up visit, pendulum exercises performed with the sling in place ( Figure 8-10 ) should be demonstrated and the patient encouraged to gently attempt them. Capable patients should be encouraged to begin home exercises, which can produce results similar to physical therapy in selected patients who are carefully instructed. Pendulum exercises should be repeated two or three times a day with progressively larger arm circles made. Patients who are unable to perform pendulum exercises at the first follow-up visit should be encouraged to initiate them at home during the upcoming week and then be evaluated again in 4 to 7 days. An inability to perform the exercises at that time should prompt reassessment of the injury and consideration of repeat radiography. If an associated injury or significant displacement or angulation is suspected, orthopedic consultation is desirable. Otherwise, referral to a physical therapist is probably necessary to assist the patient in regaining adequate function of the shoulder and arm.

Pendulum exercises. The patient should bend forward at the waist and draw circles with the elbow, starting with small circles and progressing to larger circles. Circles should be drawn in both clockwise and counterclockwise directions.

Patients able to initiate home exercises can be reevaluated approximately 2 weeks after injury. At that point, the patient should be encouraged to go without the sling for most of the day and to begin elbow range of motion (ROM) exercises. Shoulder rehabilitation to restore mobility and strength should be done two or three times per day. Whenever possible, the patient should use the injured arm for activities of daily living. The sling should be discontinued completely 2 to 4 weeks after the injury. The rehabilitation progresses from pendulum exercises in the first 2 weeks to light functional exercises without resistance in weeks 2 to 6 (e.g., placing the hand on the wall in a seated position, lying on the side and externally rotating the arm) and then active strengthening with resistance bands and weights thereafter. Go to Expert Consult for the electronic version of a patient instruction handout for shoulder rehabilitation after a fracture.

A 2-week interval between subsequent follow-up visits allows the physician to monitor the patient’s progress closely. Radiographs generally demonstrate abundant callus by 4 to 6 weeks. Functional measures of the patient’s progress include an ability to touch the lumbar spine, touch the back of the neck, and fully abduct the arm over the head. After 6 to 8 weeks, follow-up visits can be scheduled at 3- to 4-week intervals, provided ROM and function are progressing well. In the event that little progress is made or an unacceptable plateau is reached, referral to a physical therapist is strongly advised. Rehabilitation and follow-up visits should ideally be continued until both the clinician and the patient are satisfied with the functional results.

Complications

The most significant complications of proximal humerus fractures are neurovascular injury, AVN of the humerus head, and adhesive capsulitis (frozen shoulder). Fortunately, neurovascular injury and AVN are rare unless the fracture involves the anatomic neck or is severely displaced or angulated. A frozen shoulder can occur after any proximal humerus fracture. This complication can be prevented in most cases by paying careful attention to ROM and promptly referring the patient to a physical therapist whenever recovery of arm function lags behind what is expected.

Proximal humerus fractures with associated rotator cuff tars or avulsed fragment can cause loss of motion or instability. Nonunion is rare unless significant displacement has occurred and soft tissue interposition is present.

Return to Work or Sports

Patients with proximal humerus fractures can often return to work within 1 week of the injury. The sling (or collar and cuff) allows use of the hand for many tasks. These tasks may actually help the patient maintain ROM of the wrist, hand, and fingers. However, jobs or duties that demand full use of both arms will not be possible until callus is present and adequate ROM and strength are achieved to permit safe performance of the activity. This generally takes 6 to 10 weeks but may take longer. Similar criteria should be met before return to most if not all sports. Athletes and other patients who wish to maintain aerobic fitness during the healing period may find this difficult. Walking or use of a stationary bike is likely to be the safest and most comfortable approach.