Chapter 15: Upper Arm

Humeral Shaft Fractures

Humeral shaft fractures are relatively uncommon; representing only 3% of all fractures.¹ Humerus fractures are responsible for 370,000 emergency visits yearly, of which humeral shaft fractures represent about 15%. The incidence of humeral shaft fractures is relatively constant regardless of age.²

The humeral shaft extends from the insertion of the pectoralis major to the supracondylar ridges. There are four basic patterns commonly seen with humeral shaft fractures.

1. Transverse

2. Oblique

3. Spiral

4. Comminuted

The type of fracture is dependent on the mechanism of injury, the force of injury, the location of the fracture, and the muscular tone at the time of injury. Each of the above fracture patterns may be further classified on the basis of the presence of displacement or angulation (Figs. 15–1 and 15–2).

Essential Anatomy

The extensive musculature surrounding the humeral shaft may result in distraction and displacement of the bony fragments after a fracture. The deltoid inserts along the anterolateral humeral shaft, whereas the pectoralis major inserts on the medial intertubercular groove (Fig. 15–3). The supraspinatus inserts into the greater tuberosity of the humeral head, resulting in abduction and external rotation. The biceps and the triceps insert distally and tend to displace the distal fragment superiorly.

A fracture proximal to the pectoralis major insertion may be accompanied by abduction and external rotation of the humeral head because of the action of the supraspinatus (Fig. 15–3A). A fracture between the insertion of the pectoralis major and the deltoid will usually result in adduction of the proximal fragment secondary to the pull of the pectoralis major (Fig. 15–3B). Fractures distal to the deltoid insertion usually result in abduction of the proximal fragment secondary to the pull of the deltoid muscle (Fig. 15–3C).

The neurovascular bundle of the upper extremity extends along the medial border of the humeral shaft. Although any of these structures may be injured with a fracture, the most commonly injured structure is the radial nerve. The radial nerve lies in close proximity to the humeral shaft at the junction of its middle and distal thirds and fractures in this area are most often associated with radial nerve involvement (Fig. 15–4).³

Mechanism of Injury

Several mechanisms cause humeral shaft fractures. The most common mechanism of injury is direct or indirect trauma to the arm from a fall.² Direct force to the humerus typically results in a transverse fracture and an indirect mechanism results in a spiral fracture. In addition, a violent contraction in an area of pathologically weakened bone may result in a fracture.

Examination

The patient will present with pain and swelling over the area of the humeral shaft. On examination, shortening, obvious deformity, or abnormal mobility with crepitation may be detected (Fig. 15–5). It is imperative that a thorough neurovascular examination accompanies the initial assessment of all humeral shaft fractures.

The examiner should give particular emphasis to the radial nerve function and document the time at which radial nerve injury is first detected. This information is important because of the following reasons:

1. Damage at the time of injury is most often a neurapraxia.

2. Damage detected after manipulation or immobilization may lead to axonotmesis if the pressure is not relieved.

3. Damage detected during healing is typically due to a slowly progressive axonotmesis.

Radial nerve examination should include assessment of sensation over the lateral upper arm and deltoid, triceps strength, and active wrist extension. The examiner should not rely on extension of the digits as evidence of radial nerve function as the intrinsic muscles of the hand can accomplish this movement.

Imaging

Anteroposterior and lateral views of the entire humerus are essential (Fig. 15–6).

Associated Injuries

Humeral shaft fractures may be associated with several significant injuries including brachial artery injury, nerve injury, or additional fractures to the shoulder or distal humerus. Radial nerve injury is more common than ulnar or median injury. Radial nerve injury is present in approximately 8% to 11% of humeral shaft fractures.^1,3 Fractures in the middle third and middle–distal portions of the bone and transverse or spiral fracture patterns are more often associated with radial nerve injury.³ The injury may be partial or complete and may involve motor or sensory fibers. Complete motor dysfunction is present in over one-half of cases.^4,5 The majority of cases of radial nerve dysfunction occur at the time of injury, but up to 20% will develop during treatment.^6,7

Treatment

Humeral shaft fractures generally take 10 to 12 weeks to heal. Spiral fractures generally heal faster than transverse fractures because of their larger surface area. Fractures close to the elbow or the shoulder are associated with longer healing periods and higher rates of nonunion.

The emergency management of these fractures includes ice, analgesics, and application of a coaptation splint (Fig. 15–7 and Appendix A–12). A collar and cuff or sling and swathe support is then applied (Appendix A–13). The preference for collar and cuff over a sling depends on the practice pattern in your area.

The urgency of orthopedic follow-up is contingent on the underlying alignment of the fracture. Displaced or angulated fractures require urgent follow-up, as these fractures are more likely to require surgical intervention. Nondisplaced fractures with near anatomic alignment (less than 15 degrees of angulation in any plane) require less urgent follow-up.

The definitive therapy is nonoperative in most cases, and includes the continued use of the coaptation splint or functional bracing with a fitted plastic orthesis.⁸ These methods provide dependency traction as well as stabilization of the fracture through the compressive forces of the surrounding soft tissues. Functional bracing has the advantage of allowing motion at the elbow and shoulder during healing that improves functional outcome.⁹ Functional bracing is associated with acceptable clinical outcomes greater than 90% of the time.^9–11 The patient should begin hand exercises immediately; with shoulder circumduction exercises started as soon as pain permits.

Radial nerve palsies after humeral shaft fractures were historically an indication for operative exploration, but this treatment has fallen out of favor because (1) transection is present in only 12% of cases, (2) spontaneous nerve regeneration is common, and (3) delayed operative intervention does not adversely affect outcome.^3,12

Operative intervention may be accomplished with plate fixation or intramedullary nail placement.^13,14 Indications for the operative management of humeral shaft fractures are listed in Table 15–1.

Complications

Humeral shaft fractures can be associated with several significant complications.

1. The delayed development of radial nerve palsies

2. Nonunion or delayed union

3. Shoulder adhesive capsulitis (may be prevented by early circumduction exercises)

4. Myositis ossificans of the elbow (may be avoided by using active routine exercises)

5. Upper-extremity compartment syndrome

Biceps Tendon Rupture

The biceps brachii muscle is a flexor and supinator of the forearm. The muscle has two proximal attachments with the short head originating on the coracoid process and the long head just above the glenoid. The distal attachment is on the tuberosity of the radius (Fig. 15–8). Disruption of this muscle unit is not uncommon because, like the gastrocnemius and hamstring muscles, it has exposure to greater potential forces because it crosses two joints. Disruption can occur at the long head of the biceps tendon, the musculotendinous portion, muscle belly, or the distal attachment. Rupture of the long head of the biceps tendon is most common, whereas muscle disruption is least common.¹⁴ The presentation, whether proximal or distal disruption is present, is that of a “Popeye”-shaped upper arm (Fig. 15–9).

Long Head of the Biceps Tendon Rupture

Rupture of the long head of the biceps can occur anywhere along its route. The condition often occurs in men during their sixth or seventh decade of life following a chronic bicipital tenosynovitis that has left the tendon weakened. In younger patients, it may occur more suddenly, following forceful contraction of the biceps during lifting an object (e.g., weight lifting).^15–17

The patient usually notices an immediate sharp pain in the region of the bicipital groove and the biceps is noted to bulge within the arm. There is tenderness to palpation within the bicipital groove. The diagnosis can be confirmed by asking the patient to contract the biceps with the arm abducted and externally rotated to 90 degrees, at which point flexion at the elbow will cause the biceps to move away from the shoulder.¹⁸

For definitive treatment, surgical reattachment to the bicipital groove is recommended in most active patients. In elderly patients with the condition, repair may not be indicated. If the decision is made not to repair the tendon, negatives include the cosmetic appearance of the arm and a loss of elbow flexion strength of approximately 10% to 20%, which is usually well tolerated.^18,19

Patient with an acute rupture of the biceps muscle belly are treated conservatively in a Velpeau bandage with the elbow flexed to 90 degrees (Appendix A–13).

Distal Biceps Tendon Rupture

Distal biceps tendon rupture is most common in the dominant arm in men between 40 and 60 years and occurs as a result of a sudden eccentric load with the elbow flexed.^20,21 This injury is less common than proximal disruption, accounting for 3% of biceps tendon injuries, although it seems to becoming more common possibly due to an increase in the activity level of patients in their fifth and sixth decades.^22,23

Usually, there is a history of a tearing sensation accompanied by pain in the region of the antecubital fossa. Similarly to the long head of the biceps rupture, patients will present with a visible deformity of the muscle belly and weakness to flexion and supination. Partial tears may not present with the same muscle retraction and deformity, and are therefore more difficult to diagnose. Distal biceps tendon integrity can be assessed with the “hook test” where the examiner hooks their index finger under the lateral aspect of the distal biceps tendon (Video 15–1).²⁴ The squeeze test is analogous to the Thompson test for Achilles tendon rupture. With the forearm slightly pronated and resting on the patient’s leg, the examiner squeezes the biceps and should note the slight supination of the forearm if the distal biceps tendon is intact (Video 15–2). The biceps crease interval, the distance between the antecubital crease and the distal biceps muscle, can also be measured. More than 6 cm or a 20% increase in the affected arm is abnormal (Fig. 15–10). If the diagnosis is unclear, ultrasonography or MRI may be useful.

Acute complete rupture of the distal tendon of the biceps is treated with early surgical reattachment to maintain strength.^22,23 Partial tears are initially treated conservatively with immobilization. Surgical repair is reserved for refractory dysfunction.²⁵

Triceps Tendon Rupture

The triceps brachii muscle consists of three muscle groups that collectively insert on the olecranon process to extend the elbow and, to a lesser extent, adduct the arm. The long head of the triceps originates on the infraglenoid tubercle of the scapula. The medial head originates from the posterior humerus and radial groove. The lateral head originates on the posterior humerus lateral to the radial groove (Fig. 15–11).

Triceps tendon rupture is very rare, representing less than 1% of tendon injuries. The mechanism is usually a fall against an outstretched arm while the triceps is contracted with or without a blow to the posterior elbow. Hyperparathyroidism secondary to renal failure, olecranon bursitis, anabolic steroid use, or weight lifting may be contributing factors.²⁶

The tendon is usually disrupted at the insertion into the olecranon and the injury can be associated with an avulsion fracture of the olecranon. The patient presents with posterior elbow swelling and tenderness with an inability to extend the elbow against gravity. These injuries may be missed as pain in the posterior elbow limits motion at the time of injury and swelling prevents palpation of the gap caused by withdrawal of the tendon.

Treatment involves splinting at 30 degrees of elbow flexion and urgent orthopedic consultation. Most patients require surgical repair.^26–29

Arm Compartment Syndrome

There are three compartments of the upper arm. The anterior flexor compartment contains the biceps and brachialis muscles, whereas the posterior extensor compartment contains the triceps. The deltoid muscle is surrounded by its own fascia and is the third compartment.

Compartment syndrome of the upper arm is unusual and much less common than in the forearm and leg. There are several explanations for the infrequent incidence of this condition. The fascia of the upper arm musculature is thinner and more distensible. In addition, the muscles of the arm communicate with the shoulder.³⁰

Nonetheless, upper arm compartment syndrome has been reported after muscle contusion, humerus fracture, subcutaneous injection, shoulder dislocation, tendon rupture, steroid use, exercise, blood pressure monitoring after thrombolytic therapy, as a complication of dialysis access, secondary to anticoagulant use, and tourniquet use.^31–38

The clinical presentation is similar to other locations, except that upper arm compartment syndrome may not be as obvious or appear as quickly, making this condition potentially easily missed. Diagnostic measures and treatment are similar to compartment syndrome in other locations and the reader is referred to the discussion in Chapter 4 for further information.

Arm Contusions

Contusions of the muscles of the upper arm are common but not disabling injuries with no major complications. The treatment of these injuries is a sling for protection. Ice in the first 24 hours is recommended followed by heat.

The physician should rule out an underlying fracture and test for injury to the radial nerve from a contusion to the lateral aspect of the distal arm. Contusion of the radial nerve as it courses in close approximation to the humerus along the spiral groove is an infrequent injury. As the nerve courses further, it goes laterally above the lateral epicondylar ridge and is subject to contusions by a direct blow. The patient complains of a tingling sensation extending down the forearm and into the hand over the distribution of the nerve. The treatment is symptomatic.

Patients with repeated contusions to the arm may develop ectopic bone deposition. Anterior lateral humeral exostosis, also called blocker’s exostosis because of its association with American football lineman, is an abnormal deposition of bone at the attachment of the deltoid muscle onto the humerus. The injury is initiated by a direct blow in this region that produces a contusion and periostitis at the insertion of the deltoid tendon. Later, a potentially painful and irritative exostosis develops at the site of injury. When significant discomfort occurs, the patient should be referred for consideration of excision.