Matthew J. Garberina and Charles L. Getz
DEFINITION
Humeral shaft fractures, which account for about 3% of adult fractures, usually result from a direct blow or indirect twisting injury to the brachium.
These injuries are most commonly treated nonoperatively with a prefabricated fracture brace. The humerus is the most freely movable long bone, and anatomic reduction is not required.
Patients often can tolerate up to 20 degrees of anterior angulation, 30 degrees of varus angulation, and 3 cm of shortening without significant functional loss.
There are, however, several indications for surgical treatment of humeral shaft fractures:
Open fracture
Bilateral humeral shaft fractures or polytrauma; floating elbow
Segmental fracture
Inability to maintain acceptable alignment with closed treatment (ie, angulation greater than 15 degrees)—seen more commonly with transverse fractures
Humeral shaft nonunion
Pathologic fractures
Arterial or brachial plexus injury
Open reduction with internal plate fixation requires extensive dissection and operative skill. However, it offers advantages over intramedullary fixation because the rotator cuff is not violated, which leads to improved postoperative shoulder function.3
ANATOMY
The humeral shaft is defined using Key’s landmarks: the area between the upper margin of the pectoralis major tendon and the supracondylar ridge.7
The blood supply of the humeral shaft comes from the posterior humeral circumflex vessels and branches of the brachial and profunda brachial arteries.
The radial nerve and profunda brachial artery pass through the triangular interval (bordered superiorly by the teres major, medially by the medial head of the triceps, and laterally by the humeral shaft). The nerve then transverses from medial to lateral behind the humeral shaft and travels distally to a location between the brachialis and brachioradialis muscles.
The musculocutaneous nerve lies on the undersurface of the biceps muscle and terminates distally as the lateral antebrachial cutaneous nerve.
The humeral shaft has anteromedial, anterolateral, and posterior surfaces. Proximal and midshaft fractures are more amenable to plating on the anterolateral surface, whereas distal fractures often require posterior plate fixation.
PATHOGENESIS
Humeral shaft fractures occur after both direct and indirect injuries. Direct blows to the brachium can fracture the humeral shaft in a transverse pattern, often with a butterfly fragment. Injuries with high degrees of energy often result in a greater degree of fracture comminution.
Indirect injuries, such as those that can occur with activities such as arm wrestling, often involve a twisting mechanism and result in a spiral fracture pattern. Higher-energy injuries may result in muscle interposition between the fracture fragments, which can inhibit reduction and healing.
A study of 240 humeral shaft fractures revealed radial nerve palsies in 42 patients, for an overall rate of 18% (17% in closed injuries). Fractures in the midshaft were more likely to have concomitant radial nerve palsy. Twenty-five of these patients had complete recovery in a range of 1 day to 10 months. Ten patients did not have radial nerve recovery. Median and ulnar nerve palsies were seen very rarely in patients with open fractures.7
Concomitant vascular injuries are present in about 3% of patients with humeral shaft fractures.
NATURAL HISTORY
Almost all humeral shaft fractures heal with nonoperative management. The most common treatment method is initial splinting from shoulder to wrist, followed by application of a prefabricated fracture brace when the patient is comfortable, usually within 2 weeks of the injury.
Studies by Sarmiento and coauthors10,11 have shown the effectiveness of functional bracing in the treatment of humeral shaft fractures. Nonunion rates with this method of treatment are in the 4% range, lower than seen when treating with external fixators, plates, or intramedullary nails.
Closed fractures with initial radial nerve palsy can be observed, with expected recovery over a period of 3 to 6 months. Late-developing radial nerve palsies require surgical exploration.
Angulation of the humeral shaft after fracture healing is expected and is well tolerated when it is less than 20 degrees. Varus deformity is most common.10
Adjacent joint stiffness of the shoulder and elbow also is common. If the situation dictates treatment, physical therapy reliably restores joint motion in these patients.
Relative contraindications to closed treatment include bilateral humeral shaft fractures or patients with polytrauma who require an intact brachium to ambulate. Transverse fractures and those with significant muscle imposition also are more amenable to operative fixation.11
PATIENT HISTORY AND PHYSICAL FINDINGS
The examining physician must perform a complete examination of the affected limb to rule out concomitant injuries.
The skin should be thoroughly evaluated for evidence of an open fracture. This includes examination of the axilla. Entry and exit wounds are sought in gunshot victims. Swelling is common, and the patient may have an obvious deformity.
The patient often braces the affected limb to his or her side, making evaluation of shoulder and elbow range of motion difficult. Bony prominences should be gently palpated to evaluate for other injuries, such as an olecranon fracture.
Evaluate the appearance and skeletal stability of the forearm to rule out the presence of a co-existing both-bone forearm fracture (“floating elbow”). This finding necessitates operative fixation of humeral, radial, and ulnar fractures.
Determine the vascular status of the upper extremity by palpating the radial and ulnar pulses at the wrist. Compare these findings with the unaffected limb. Selected cases may require Doppler arterial examination.2
A complete neurologic assessment is necessary, with particular attention focused on the status of the radial nerve. This structure is at risk proximally as it passes posterior to the humeral shaft after emerging from the triangular interval, as well as distally, as it lies adjacent to the supracondylar ridge (near the location of the Holstein-Lewis distal one-third spiral humeral shaft fracture).
Examine sensory function in the first dorsal web space, wrist extension, and thumb interphalangeal joint extension to determine the functional status of the radial nerve.
IMAGING AND OTHER DIAGNOSTIC STUDIES
At least two plain radiographs at 90-degree angles to each other are necessary to evaluate the displacement, shortening, and comminution of the humeral shaft fracture.
Radiographic views of the shoulder and elbow are necessary to rule out proximal extension of the shaft fracture or concomitant elbow injury (ie, olecranon fracture). This is especially important in high-energy injuries
If swelling or evidence of skeletal instability about the forearm is present, dedicated forearm radiographs can determine the presence of a floating elbow (ie, ipsilateral humeral shaft fracture plus both-bone forearm fractures).
DIFFERENTIAL DIAGNOSIS
Distal humerus fracture
Proximal humerus fracture
Elbow dislocation
Shoulder dislocation
NONOPERATIVE MANAGEMENT
Most isolated humeral shaft fractures can be treated nonoperatively. Initial treatment can vary with fracture location and involves splinting in either a posterior elbow or coaptation splint. The elbow is positioned in 90 degrees of flexion. An isolated humeral shaft fracture rarely necessitates an overnight hospital stay.
In the past, definitive nonoperative treatment involved coaptation splinting or the use of hanging arm casts. Currently, functional fracture bracing provides adequate bony alignment, while local muscle compression and fracture motion promote osteogenesis. These braces provide soft tissue compression and allow functional use of the extremity.11
Timing of brace application depends on the degree of swelling and patient discomfort. On average, the brace is applied about 2 weeks after the injury. A collar and cuff help with initial patient comfort and should be worn during recumbency until the fracture heals.
The brace often requires frequent retightening over the first 2 weeks as swelling subsides. Elbow and wrist range-of-motion exercises out of the sling are encouraged.
Functional bracing requires that the patient be able to sit erect, and weight bearing on the humerus is not allowed. The level of humeral shaft fracture does not preclude the use of functional bracing, even if the fracture line extends above or below the brace.
Anatomic alignment of the humerus rarely is achieved, with varus deformity most common. However, patients often are able to tolerate the bony angulation and still perform activities of daily living after injury. A cosmetic deformity rarely exists.
Pendulum exercises are encouraged as soon as possible post-injury. Active elevation and abduction are avoided until bony healing has occurred, to prevent fracture angulation. The surgeon obtains radiographs after brace application and again 1 week later. If alignment is acceptable, repeat radiographs are obtained at 3to 4week intervals until fracture healing occurs.10,11
SURGICAL MANAGEMENT
Certain humeral shaft fractures are not amenable to conservative treatment. Open fractures or high-energy injuries with significant axial distraction are treated with open reduction and internal fixation. Patients with polytrauma, bilateral humeral shaft fractures, vascular injury, or an inability to sit erect are best treated with operative fixation. Unacceptable fracture alignment requires abandonment of nonoperative treatment. Finally, humeral shaft nonunion is a clear indication for open reduction and internal fixation with bone grafting.4,9
Preoperative Planning
The surgeon must review all radiographic images and must rule out ipsilateral elbow or shoulder injury.
Preoperative radiographs help the surgeon estimate the required plate length. Higher-energy injuries with comminution may benefit from plating and supplemental bone grafting. The surgeon must plan for various scenarios based on these studies: moderate comminution or bone loss can be addressed with cancellous allograft or autograft bone, whereas more extensive bone defects may require strut grafting.
Proximal and middle-third humeral shaft fractures are addressed using an anterolateral approach. Distal-third humeral shaft fractures often are treated via a posterior approach, because the distal humeral shaft is flat posteriorly, making it an ideal location for plate placement.
Fracture patterns with extension into the proximal humerus can be exposed with a deltopectoral extension to the anterolateral humeral dissection.
The surgeon notes any pre-existing scars that may affect the desired surgical approach, and neurovascular status is documented, with particular attention to radial nerve function.
Positioning
Positioning depends on the intended surgical approach. For an anterolateral or medial approach, the patient is brought to the edge of the bed in the supine position. A hand table is attached to the bed and the patient’s injured arm is placed on the hand table in slight abduction (FIG 1A).
FIG 1 • A. Positioning for the anterolateral approach to the humeral shaft with the shoulder abducted and the arm on a hand table. B. Positioning for the posterior approach to the humeral shaft with the patient in the lateral decubitus position.
For a posterior approach, the patient can be placed prone or in the lateral decubitus position. A stack of pillows can support the brachium during the procedure (FIG 1B).
Approach
The approach depends on fracture location and the presence of any previous surgical incisions. The anterolateral and posterior approaches to the humerus are used most commonly, for proximal two-third and distal third fractures, respectively.
In patients who have already undergone multiple procedures to the affected extremity, Jupiter6 recommends consideration of a medial approach to take advantage of virgin tissue planes.
TECHNIQUES
ANTEROLATERAL APPROACH TO THE HUMERUS
The incision courses over the lateral aspect of the biceps, beginning proximally at the deltoid tubercle and terminating just proximal to the antecubital crease (TECH FIG 1).
A tourniquet rarely is used, because it often limits proximal exposure.
The lateral antebrachial cutaneous nerve lies in the distal aspect of the incision and must be protected during exposure.
Bluntly enter the interval between the biceps and brachialis by sweeping a finger from proximal to distal.
TECH FIG 1 • A. Anterolateral incision. B. Skin and subcutaneous tissue incised. C. Retractor on brachialis muscle, forceps on brachioradialis. D. Musculocutaneous nerve on undersurface of biceps muscle. E. Radial nerve in interval between brachialis and brachioradialis. F. Biceps lifted to reveal brachialis muscle. G. Brachialis muscle split in its lateral third.
At the level of the midhumerus, identify the musculocutaneous nerve on the undersurface of the biceps muscle. Trace this nerve out distally to protect its terminal branch, which forms the lateral antebrachial cutaneous nerve.
Distally, the interval between the brachialis and brachioradialis is dissected to expose the radial nerve. Protect the radial nerve with a vessel loop so that it can be identified at all times.
The brachialis is split in line with its fibers between the medial two thirds and lateral one third. This is an internervous plane between the radial nerve medially and the musculocutaneous nerve laterally.
Identify the fracture site and proceed with reduction and fixation.
POSTERIOR APPROACH TO THE HUMERUS
Make a generous incision over the midline of the posterior arm extending to the olecranon fossa (TECH FIG 2).
Identify the interval between the long and lateral heads of the triceps proximally. Bluntly dissect this interval, taking the long head medially and the lateral head laterally.
Distally, several blood vessels cross this plane; they require coagulation before transection.
Identify the radial nerve proximal to the medial head of the triceps in the spiral groove. Protect the radial nerve throughout the case.
Split the medial head of the triceps in its midline from proximal to distal to expose the fracture site.
TECH FIG 2 • A. Incision for posterior approach. B. Superficial triceps split. C. Deep triceps split. D. The probe points to the radial nerve as it exits the spiral groove from medial to lateral; the fracture site is seen distally.
FRACTURE REDUCTION
Sharp periosteal dissection exposes the fracture site. Evaluate the degree, if any, of comminution.
Limit periosteal stripping to adequately expose the fracture. Make every attempt to leave some soft tissue attached to each fragment so as not to devascularize the fragments.
Gentle traction and rotation often can bring the fracture fragments into better alignment.
Anatomically reduce the fracture with one or more reduction clamps. It is advisable to reduce the fracture completely before definitive fixation, and this often requires the use of multiple reduction clamps (TECH FIG 3).
After the fracture is reduced, the fragments can be provisionally fixed with Kirschner wires. Place the wires so as not to interfere with plate fixation.
Alternatively, 3.5 or 4.5-mm interfragmentary screws can be used to hold the fracture aligned until plate fixation.
Transverse fractures with minimal comminution often can be directly reduced with the plate and Faberge clamps.
TECH FIG 3 • A. Fracture reduction maintained temporarily. B. Hold the plate over the reduced fracture with a plateholding clamp.
EXPOSURE OF FRACTURE NONUNION
Exposure of the radial nerve is more challenging, but it is very important in this situation. In many cases it is best to dissect out the nerve distally in the interval between the brachialis and brachioradialis and proximally medial to the spiral groove. The nerve is then carefully dissected free from the nonunion site.
Pinpoint the exact location of the nonunion with a no. 15 scalpel.
The ends of the nonunion can be brought out through the wound, and all fibrous material is extracted.
After thorough fracture débridement, the amount of bone loss becomes clear. The surgeon can now determine whether standard cancellous bone grafting or strut grafting is necessary.
PLATE APPLICATION
After fracture reduction, the plate length is determined.
Humeral shaft fractures require at least six cortices of fixation above and below the fracture site.
In larger bones, a broad 4.5-mm dynamic compression plate can provide optimal fixation. In smaller bones, a 4.5-mm limited contour dynamic compression plate often provides a better fit.
Provisionally place the plate on a flat surface of the humerus and hold it in place with a plate-holding clamp.
4.5-mm cortical screws are placed through the plate holes proximal and distal to the fracture. Compression techniques can be used, where appropriate.
Ensure that no soft tissue, especially nerve, is trapped between the plate and the bone.
Make sure to obtain screw purchase in at least six cortices above and below the fracture (TECH FIG 4).
Cerclage wiring over the plate can add supplemental fixation, especially in weak bone.
Rotate the arm and flex and extend the elbow to evaluate fracture stability.
Apply cancellous bone graft into defects as needed.
TECH FIG 4 • A. Plate spanning the fracture site with at least six cortices of fixation proximally and distally. B. Anterior plate with a probe pointing to the radial nerve as it exits the spiral groove posteriorly (proximal is to the right, distal to the left). C. Supplemental cerclage wire fixation can augment stability in weak bone.
MEDIAL APPROACH
Positioning is similar to the anterolateral approach.
Make an incision over the medial intermuscular septum from the axilla to 5 cm proximal to the medial epicondyle (TECH FIG 5).
Mobilize the ulnar nerve.
Resect the medial intermuscular septum; identify and coagulate the adjacent venous plexus with bipolar electrocautery.
Mobilize the triceps posteriorly and the biceps/brachialis anteriorly.
Expose the fracture site.
The axillary incision raises concern for infection; there is also concern that the ulnar nerve can scar to the plate.
TECH FIG 5 • A. Incision for the medial approach. B,C. The brachialis and biceps are raised anteriorly, and the triceps is raised posteriorly for fracture exposure.
PEARLS AND PITFALLS
POSTOPERATIVE CARE
Postoperative radiographs ensure proper fracture alignment and plate placement (FIG 2).
Initially, the patient can be placed in a sling or posterior elbow splint. This is removed and range-of-motion exercises are started when patient comfort allows (usually 1 to 2 days postoperative).
Weight bearing on the affected upper extremity is allowed based on patient comfort.12
Initial therapy consists of elbow range-of-motion and shoulder pendulum and passive self-assist exercises.
The patient can come out of the sling after 2 weeks and start waist-level activities with the operative arm.
At 6 weeks, elbow motion should be near normal range, and shoulder strengthening is added to the patient’s physical therapy.
At 3 months, radiographs should reveal some callus formation. If no callus is evident, radiographs are repeated every 6 weeks until evidence of healing appears.
FIG 2 • Postoperative radiograph.
OUTCOMES
Plate fixation leads to union in 90% to 98% of cases.
Plating offers decreased complication rates compared to intramedullary nailing, especially in terms of shoulder dysfunction.8
Iatrogenic radial nerve palsy occurs in about 2% to 5% of cases and usually resolves in 3 to 6 months. Electromyography helps monitor return of nerve function in patients with prolonged palsy. Radial nerve exploration is indicated when no nerve function returns by 6 months.
Elbow and shoulder range of motion usually return to normal postoperatively.
COMPLICATIONS
Infection
Nonunion
Malunion
Hardware failure
Radial nerve palsy
Shoulder impingement
Elbow stiffness
REFERENCES
· Garberina MJ, Getz CL, Beredjiklian P, et al. Open reduction and internal fixation of humeral shaft nonunions. Tech Shoulder Elbow Surg 2006;7:131–138.
· Gregory PR. Fractures of the shaft of the humerus. In Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults, ed 5, vol 1. Philadelphia: Lippincott Williams & Wilkins, 2001:973–996.
· Gregory PR, Sanders RW. Compression plating versus intramedullary fixation of humeral shaft fractures. J Am Acad Orthop Surg 1997;5:215–223.
· Healy WL, White GM, Mick CA, et al. Nonunion of the humeral shaft. Clin Orthop Relat Res 1987;219:206–213.
· Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. Philadelphia: Lippincott Williams & Wilkins, 1994:51–82.
· Jupiter JB. Complex non-union of the humeral diaphysis: Treatment with a medial approach, an anterior plate, and a vascularized fibular graft. J Bone Joint Surg Am 1990;72A:701–707.
· Mast JW, Spiegel PG, Harvey JP Jr, et al. Fractures of the humeral shaft: A retrospective study of 240 adult fractures. Clin Orthop Relat Res 1975;112:254–262.
· McCormack RG, Brien D, Buckley RE, et al. Fixation of fractures of the shaft of the humerus by dynamic compression plate or intramedullary nail: a prospective randomized trial. J Bone Joint Surg Br 2000;82B:336–339.
· Ring D, Perey BH, Jupiter JB. The functional outcome of operative treatment of ununited fractures of the humeral diaphysis in older patients. J Bone Joint Surg Am 1999;81A:177–190.
· Sarmiento A, Latta LL. Functional fracture bracing. J Am Acad Orthop Surg 1999;7:66–75.
· Sarmiento A, Waddell JP, Latta LL. Diaphyseal humeral fractures: Treatment options. J Bone Joint Surg Am 2001;83A:1566–1579.
· Tingstad EM, Wolinsky PR, Shyr Y, et al. Effect of immediate weightbearing on plated fractures of the humeral shaft. J Trauma 2000;49:278–280.