eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity

Midshaft Humerus Fractures: Treatment

Author: Matthew W Lawless, MD, Assistant Professor of Orthopedic Surgery, Wright State University School of Medicine; Consulting Surgeon, Department of Orthopedic Surgery, Miami Valley Hospital and Dayton Veterans Affairs Medical Center
Contributor Information and Disclosures

Updated: Jan 8, 2008

Treatment

Medical Therapy

Most closed fractures of the humeral shaft can be treated successfully with closed methods; union rates of more than 90% are often reported.^4,13,14 Multiple closed techniques are available, including the employment of traction, as well as the use of the hanging arm cast, co-aptation splint, Velpeau dressing, abduction humeral/shoulder spica cast, or functional brace.^4,13 All of these techniques have been used successfully, but closed humeral shaft fractures are usually treated with a hanging arm cast or a co-aptation splint for 1-3 weeks, after which they are placed in a functional brace.^4,5,6,14

No recommendations have been reported regarding the use of the hanging arm cast versus the co-aptation splint, although Rockwood recommends using hanging arm casts initially for oblique or spiral fractures with shortening, when the cast is able to extend at least 2 cm proximal to the fracture site.⁴ When a hanging arm cast is employed, it should be replaced, once reduction is adequate, with another treatment method or should be monitored very closely to look for fracture distraction and nonunion.¹⁴ In some cases, a functional arm brace also can be applied as the initial treatment.

Sarmiento and colleagues first used the functional brace in 1977.¹⁵ This device consists of anterior and posterior plastic shells that are held together with Velcro straps. The fracture is kept in position through soft-tissue compression, and the brace is tightened as the swelling decreases. Over-the-shoulder extensions are available but are rarely necessary. A functional brace should not be used when massive soft-tissue injury or bone loss has occurred, when an acceptable fracture alignment cannot be maintained, or if the patient is unreliable or uncooperative.¹⁶

For many of the nonoperative treatments (eg, functional bracing, hanging arm casts, co-aptation splinting) to work most effectively, the patient should remain upright, either standing or sitting, and should avoid leaning on the elbow for support. This allows gravitational force to assist in fracture reduction. The patient should begin ROM exercises of the fingers, wrist, elbow, and shoulder as soon as these can be tolerated.

A Velpeau dressing or a sling and swathe (which is similar to the Velpeau dressing but is less restrictive) is typically used in nondisplaced or minimally displaced fractures in children younger than 8 years, as well as in elderly patients who are unable to tolerate other treatment methods. Pads can be placed in the axilla to control fracture angulation.¹⁴

Acceptable alignment of humeral shaft fractures is considered to be 3 cm of shortening, 30° of varus/valgus angulation, and 20° of anterior/posterior angulation.^5,17 Varus/valgus angulation is tolerated better proximally, and more angulation may be tolerated better in patients with obesity. Patients with large, pendulous breasts who are treated nonsurgically are at increased risk of varus angulation. No set values for acceptable malrotation exist, but compensatory shoulder motion allows for considerable tolerance of rotational deformity.⁵

Low-velocity gunshot wounds act as closed injuries after initial treatment (debridement of skin at the entry and exit sites and a single dose prophylactic antibiotics).⁵

Surgical Therapy

Surgical fixation using plates and screws

Open reduction and internal fixation (ORIF) with direct fracture exposure often yields near anatomic alignment. The rates of nonunion and hardware failure requiring revision range from 0-7%.^9,18 The ROM of the elbow and shoulder predictably returns after plate fixation; when complete motion is not obtained, it is often the case that other associated skeletal or neurologic injuries exist.¹⁰ Evidence also suggests that immediate weight bearing on an upper extremity that has been treated with ORIF has little or no deleterious effect.¹⁹ The most common complications associated with plating procedures are iatrogenic nerve palsy (0-5%, with most cases being a transient problem that requires no further intervention) and infection (0-6%).^9,18,20

The 2 approaches that are used for fracture exposure and plate application are the posterior approach and the anterolateral approach. Either approach is adequate for fractures in the midthird and distal third, but fractures in the proximal third often require the anterolateral approach.^4,5,10,14

The posterior approach exploits the interval between the lateral and long heads of the triceps (best found proximally). The medial head of the triceps is then incised down the midline to expose the posterior aspect of the humeral shaft.²¹

If additional proximal exposure is required, the extensile posterior approach can be used. This approach involves identifying the lower lateral brachial cutaneous nerve and radial nerve distally and then resecting the distal 3 cm of the lateral septum. This allows medial retraction of the radial nerve. The medial and lateral heads of the triceps then can be elevated off the lateral intermuscular septum and bone. This extensile posterior approach allows exposure of the shaft proximally to the axillary nerve.²² The radial nerve crosses the posterior aspect of the humerus, where it is, on average, 20.7 cm (±1.2 cm) proximal to the medial epicondyle and 14.2 cm (±0.6 cm) proximal to the lateral condyle.²²

In the anterolateral approach, 2 different internervous planes are used. Proximally, the plane is between the deltoid and pectoralis major. Distally, the plane lies between brachialis' medial fibers (ie, the musculocutaneous nerve) and its lateral fibers (ie, the radial nerve).²¹

Care should be taken to avoid excessive soft-tissue stripping and the devitalization of butterfly fragments. A 4.5-mm–broad dynamic compression plate (or a narrow plate in smaller individuals) is typically selected. Lag screws should be inserted when possible, and 5-10 cortices of fixation (proximal and distal to the fracture site) should be obtained. Fracture stability should then be assessed.^4,5,6,13,14

The need for additional bone grafting is determined at the time of surgery. A low threshold for the addition of cancellous bone grafting should be maintained.⁴

Some surgeons prefer not to plate humeral shaft fractures because of the difficulties of dealing with fracture exposure, the technical aspects of plating, and complex fracture patterns, as well as because of concerns about radial nerve injury.^10,23

Surgical fixation with intramedullary implants

Intramedullary (IM) fixation has gained popularity over the last several years. Initial reports revealed that there was a higher nonunion rate following such fixation than there was with conservative treatment or with ORIF with plates and screws. However, several reports have demonstrated that with newer implants and improved techniques, locked IM nailing can achieve a success rate as high as that of the other methods.^{1,20,24,25,26,27,28,29,30,31,32,33} In these studies, the incidence of nonunion is approximately 6%, the incidence of infection is 2%, and the incidence of radial nerve palsies is 3%. IM nailing can be used to stabilize fractures that are 2 cm below the surgical neck to 3 cm proximal to the olecranon fossa.⁵ Results comparing ORIF with locked IM nailing have failed to demonstrate any difference in blood loss or operating room time.^10,20

IM nails have certain potential advantages over plates and screws. The IM nail is closer to the normal mechanical axis and can act as a load-sharing device if there is cortical contact. The nails are subjected to lower bending forces, making failure by fatigue less likely to occur.⁵ IM nails can be placed without direct fracture exposure and with much less soft-tissue dissection. Additionally, cortical osteopenia caused by stress shielding (as seen with plates and screws) is less likely.

Standard locked intramedullary humeral nails can also be inserted either antegrade or retrograde. The antegrade approach typically involves a starting point at the proximal humerus; this point can be through the rotator cuff, where the tissue is less vascular, or just lateral to the articular surface, where the blood flow is higher.

The procedure can be started with a small incision made with the aid of fluoroscopy or with a larger incision, where the cuff is identified and purposefully incised. No evidence has indicated that either method is superior.^34,35,36 The nail can be placed with or without reaming (no evidence suggests that either method is superior with regard to healing time and complication rate) and then be locked proximally and distally.¹⁰ Care must be exercised when placing the proximal locking screws because the axillary nerve lies 5-6 cm distal to the edge of the acromion.²³ The distal locking screw can often be placed lateromedial or anteroposterior. The lateromedial technique puts the radial nerve at risk, and the anteroposterior method places the musculocutaneous nerve at risk. An alternative and possibly safer method involves placing the screw posteroanteriorly.⁶

Retrograde insertion requires a distal triceps splitting approach and a hole placed 2.5 cm proximal to the olecranon fossa, measuring 1 cm in width and 2 cm in length.¹⁰ The starting hole must be beveled along the path of the nail insertion.⁶ The nail can be locked proximally, either lateromedially (placing the axillary nerve at risk) or anteroposteriorly (placing the biceps tendon at risk). If any resistance is met while attempting to pass the nail, either antegrade or retrograde, consideration should be given to making a small incision to ensure that the radial nerve is not entrapped in the fracture site.

The use of flexible nails (often Ender nails with a 3.5-mm diameter) has become limited to isolated cases of transverse or short oblique fractures with a canal larger than 7 mm. These nails can be inserted either retrograde (more common, triceps splitting with an entry portal just above the olecranon fossa) or antegrade. These nails can be locked at the end with wire or 3.5-mm cortical screws to prevent migration, but no method of statically locking these nails exists. Therefore, bending and angulation can still occur in spiral or comminuted fractures. Furthermore, a canal of less than 7 mm only allows insertion of 1 nail.¹⁰

The outcome of humeral fractures treated with flexible IM nailing (Ender nails) reveals that antegrade insertion is associated with shoulder dysfunction (pain and decreased ROM) in 5-10% of patients and that hardware removal is not entirely effective in relieving symptoms.^37,38,39 A starting point outside the rotator cuff may help to decrease these numbers. Reports on the use of Rush rod fixation have demonstrated unacceptably high rates of nonunion, delayed union, and shoulder pain.⁴⁰ With retrograde nailing, union rates vary from 91-98%, and infection (which is mostly associated with open fractures) varies from 0-2%. With the use of multiple nails, hardware failure is reported to be rare, and the rate of iatrogenic radial nerve injury, which is usually temporary, is placed at 3%.¹⁰

Locked IM nailing in an antegrade fashion has resulted in loss of shoulder motion in 6-37% of cases.^34,36 It has also been reported that retrograde nailing is not associated with shoulder pain and that the return of elbow motion is not a problem unless other associated injuries are located in the fractured extremity.¹⁰ A concern also exists that, once the retrograde nail has been placed, the starting hole just distal to this may act as a stress riser.²³ Biomechanical studies have shown that, for midshaft fractures, retrograde and antegrade nailing showed similar initial stability, bending, and torsional stiffness. In proximal fractures (10 cm distal to the greater tuberosity tip), the antegrade nails have demonstrated significantly more initial stability and higher bending and torsional stiffness, as has been true for distal fractures with retrograde nailing.⁴¹

Nonunions in humeral fractures after treatment with plate and screws typically respond well to replating with the addition of bone graft. This is not the case when nonunions follow treatment with humeral nails. If a humeral nonunion treated with an IM nail is treated with exchange nailing, the success rate can be as low as 40-60%.^36,42 However, if the nail is removed and ORIF with bone grafting is performed, the union rate is again very high. However, this is a more technically difficult scenario.²³

Surgical fixation with external fixators

Traditionally, the external fixation of humeral shaft fractures has been limited to open fractures. The open wound should be treated in an appropriate manner and, for Gustilo grade I or II wounds, be followed by ORIF or unreamed IM nailing. For grade III wounds, external fixation is the treatment of choice. Debridements are performed every 48 hours until the wound is clean. Then, at the final debridement, bone grafting may be used if needed.¹⁴ A high complication rate has been associated with the treatment of humeral shaft fractures with an external fixator.⁴³

Preoperative Details

The patient's position for surgery is determined by the method chosen for fixation. Antegrade nailing of the humerus is performed with the arm draped free and the patient in either a beach chair or a supine position. For the placement of distal locking screws, the c-arm can be rotated 180° so that the top can be used as a table to support the arm. Retrograde nailing is performed with the patient in the prone position and the arm supported on a radiolucent arm board.

Positioning for placement of plates and screws is again determined by the approach chosen. During a posterior approach, the patient is positioned prone, with the arm over an arm board. The patient is positioned supine for an anterior approach, with the extremity placed in about 60° of abduction on an arm board.

External fixation is performed with the patient supine and the arm on an arm board.

Complications

Radial nerve injury occurs in up to 18% of humeral shaft fractures.⁴⁴ Although the oblique distal third humeral fracture (Holstein-Lewis) is better known than are other humeral shaft fractures for an association with radial nerve palsy, such palsy most commonly occurs with middle third humeral fractures.⁴⁵ Most of these nerve injuries are neurapraxic or axonotmetic types, 90% of which resolve to at least grade IV strength in 3-4 months.^9,45

Indications for early nerve exploration include a palsy associated with an open wound or penetrating injury.⁵ Whether or not it is best to explore a radial nerve after function decreases following closed manipulation has sparked controversy. Some authors recommend waiting to perform exploration if no return of function is observed after 3-4 months.⁴⁶ The proponents of this argument state that the results of secondary repair of radial nerve injuries are as good as those of primary repair and that the situation has been made easier because the fracture has had time to heal.⁴

Brachial artery injuries that are associated with humeral shaft fractures are uncommon. At risk fractures are those in the proximal and distal thirds of the arm.⁴ Surgical stabilization of fractures associated with arterial injury is mandatory at the time of vascular repair.

Four months has been noted to be an adequate period for humeral shaft fractures to heal. The nonunion rate reportedly varies from 1-15%. A higher nonunion rate for humeral shaft fractures has been associated with transverse fractures, as well as with such factors as fracture distraction, soft-tissue interposition, inadequate shoulder immobilization, and decreased shoulder motion.^47,48,49

Medical factors that decrease the union rate include diabetes mellitus, corticosteroid use, older age, poor nutritional status, obesity, fractures underlying a burn, and previous radiation.^50,51 Functional bracing has little role in nonunion. Electrical stimulation may be beneficial but should not be used when infection, a gap of more than 1 cm, or a synovial pseudarthrosis is present. ORIF with compression plates and screws, with or without the aid of bone grafting, is considered to be the treatment of choice for most established nonunions.⁵ Some reports describe nonunions being treated with retrograde IM nails and antegrade nails, with a union rate similar to that associated with ORIF.^20,52

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