Humeral Shaft Fractures
Humeral shaft fractures account for about 1% of acute fractures in trauma registries, with an incidence of 14.5 per 100,000 people per year. Most humeral shaft fractures occur in the elderly as a result of a simple fall.1 Despite the nearly universal acceptance of intramedullary nailing for fractures of the long bones of the lower extremity, nonoperative management remains the treatment of choice for many humeral shaft factures. For those fractures that require stabilization, both plating and nailing have similar results, although with slightly different complications. Each method has advantages and disadvantages, which are discussed at length in this chapter.
Associated injuries to the radial nerve occur in 6 to 17% of humeral shaft fractures, and are most commonly seen in displaced transverse fractures in the mid-diaphysis. Thus, it is mandatory for the clinician to perform and document a motor examination specifically testing wrist extension for every humeral fracture at the time of initial presentation. It should be noted that a common mistake, often made after splinting the arm and wrist, is to observe extension of the fingers, which is a test of the intrinsic muscles of the hand and their innervation by the ulnar nerve, rather than the radial nerve. Evaluation of the radial nerve is performed by testing wrist extension with grading of the motor function.
Nonoperative Treatment
General Concepts
Nonsurgical management is currently considered the treatment of choice for most isolated humeral shaft fractures. The predictably good results achieved with functional bracing in particular have been noted by Sarmiento et al,2–4 who reported union rates near 99% when treating closed and low-energy open fractures. Other methods of nonoperative management include coaptation splints, hanging arm casts, and a variety of slings and swaths. These methods are discussed in subsections that follow below.
Nonoperative management is not ideal for certain fractures and in certain situations. For example, problems with the nonoperative management of isolated humeral shaft fractures are more common when treating displaced transverse fractures, which are prone to nonunion, and in fractures with persistent angulation greater than 20 degrees. This amount of angulation may contribute to a decreased range of motion of the shoulder; in particular, varus angulation is associated with loss of functional shoulder abduction. In contrast, shortening of the humerus does not appear to cause a functional problem. Castellá et al5 reported on a series of 30 humeral nonunions occurring after nonoperative management; nine were in elderly women with the same fracture pattern—a long lateral butterfly fragment at the junction of the middle and distal thirds of the humerus. Other authors have reported that fractures that occur in the proximal one third of the humerus and are also associated with significant shoulder dysfunction at 12 weeks after injury have higher rates of nonunion and may be best treated with surgical fixation.6
Coaptation Splinting
Coaptation splints are often the first choice for the initial stabilization of humeral shaft fractures in the emergency department. The splint is U-shaped and should be advanced as far up into the axilla as possible on the medial side of the arm and extend around the elbow to end above the deltoid on the lateral side (Fig. 15.1). For more proximal fractures, extending the lateral segment of the splint above the shoulder to the side of the neck will increase the amount of shoulder immobilization, which may result in improved pain control during the first week after injury. A tubular stockinette can be placed around the splint and tied loosely around the neck to prevent the splint from slipping when above-the-shoulder immobilization is desired. Fractures treated in coaptation splints may develop varus angulation due to the positioning of the arm against the body, especially if the axillary segment of the cast ends at or distal to the fracture (Fig. 15.2). To prevent varus deformity, the splint must often be molded into valgus (banana shaped). The axillary end of the splint should be well padded, and desiccating powder can be applied to avoid skin complications in this area. Weekly radiographs should be monitored to ensure appropriate fracture positioning with this technique. Like the hanging arm cast, coaptation splinting may be used for the initial postinjury period before conversion to functional bracing for definitive treatment.
Functional Bracing
Functional bracing is an effective method of obtaining union in humeral shaft fractures that allows shoulder and elbow motion while promoting fracture union. Functional bracing works by providing circumferential compression to the soft tissue, resulting in an increase in the hydrostatic pressure around the fracture. Functional bracing allows motion of the adjacent joints while immobilizing the fracture. Active muscle use assists in reducing fracture angulation and rotation.4
Humeral fracture braces consist of two shells, one fitting inside the other (Fig. 15.3). One shell is formed to fit the bicep muscle belly, and the other fits the triceps. The shells should not impinge on the elbow area or impede elbow motion. Two or three Velcro straps allow tightening of the brace to a snug fit. The adjustability of the braces allow them to be placed as early as 5 to 7 days after injury, regardless of the amount of swelling, and subsequent tightening of the brace is done as swelling subsides. Functional braces are poorly tolerated immediately following injury. Therefore, initial immobilization for 1 to 2 weeks with a coaptation splint, hanging arm cast, or Velpeau sling is recommended. Patients are allowed to perform activities as tolerated with the extremity; however, shoulder abduction should be limited until the fracture unites to decrease the tendency for varus angulation to occur. Brace treatment will be necessary for approximately 8 weeks or until the patient has pain-free motion with radiographic evidence of union. There are several large series documenting that nonunions are uncommon with the use of functional orthosis.2–4
Hanging Arm Casts
The use of hanging arm casts for the management of displaced humeral shaft fractures was based on the rationale that gravity, acting upon the weight of the cast, would align the arm. Humeral fractures amenable to treatment with hanging arm casts include fractures with shortening and those having a long oblique or spiral pattern. These fractures can withstand the potential lengthening that occurs with this method of treatment. In contrast transverse fracture patterns are not ideally treated with this method, due to the potential for overdistraction and resultant nonunion that may occur. A hanging cast may be applied in the first week following injury to obtain reduction. After this time, transition to functional bracing is preferred due to the risk of shoulder and elbow stiffness following the prolonged immobilization that is required with a hanging arm cast. This technique is gravity dependent and requires the patient to stay in an upright position at all times to keep the fracture reduced. Otherwise, the weight of the cast could actually contribute to fracture displacement. Patients may dislike this technique due to the need to sleep upright in a chair or recliner. Patients should be counseled to avoid resting their arm on tables or arm rests to prevent displacement of the fracture. The hanging cast should be lightweight to minimize the potential for overdistraction and should extend from a point proximal to the fracture, holding the elbow at 90 degrees of flexion with the forearm in neutral rotation. The cast should leave the hand free to allow wrist and finger motion. The cast is suspended from a loop around the patient′s neck and connected to the cast near the wrist. Adjustments in the position of the loop can be made depending on the type of deformity that is present. Varus deformities require moving the loop more laterally (away from the body), and fractures in valgus can be corrected by connecting the loop more medially (toward the abdomen). Apex anterior angulation can be corrected by moving the attachment more distally, whereas apex posterior angulation requires moving the loop to a more proximal attachment. Frequent radiographs should be obtained in the first weeks following injury when using a hanging arm cast so that malalignment and overdistraction of the fracture can be identified and adjustments made to correct these deformities.
Other Nonoperative Treatment Methods
There are several other nonoperative methods that have been described to treat humeral shaft fractures. Velpeau dressings completely immobilize the upper extremity and should be used only as a temporizing method until other methods are appropriate. Shoulder spica casting has been used for fractures requiring significant abduction to reduce. These casts are difficult to apply and awkward to wear. Surgical treatment is preferred for fractures that would otherwise require shoulder spica casting. Skeletal traction utilizing a transolecranon pin has been previously used for treatment. External fixation is much simpler to use and has replaced any indication for skeletal traction in the treatment of humeral shaft fractures.
Injury Classification
Classification of humeral shaft fractures is done on a descriptive basis, with multiple features of the fracture taken into account. Diaphyseal fractures can be classified by location: proximal third, middle third, and distal third. However, a more useful description is the location of the fracture with respect to the muscular insertions on the humerus. In the proximal aspect of the diaphysis, the deforming forces on fractures include the pectoralis major and deltoid. Thus, fractures occurring above the pectoralis major insertion will be deformed, with the distal segment being displaced medially by the pull of the pectoralis major muscle. In this case, the proximal fragment will be abducted and externally rotated by the forces applied by the rotator cuff. In a humeral shaft fracture occurring between the insertions of the pectoralis major and the deltoid, the proximal shaft will displace medially due to the pull of the pectoralis major, whereas the distal shaft will be displaced proximally and laterally by the pull of the deltoid (Fig. 15.4). In fractures occurring below the insertion of the deltoid, the stronger deltoid will cause the proximal fragment to displace into abduction, overpowering the pectoralis major.
In addition to localization of the fracture, the classification should include a description of the fracture pattern, using terms such as transverse, spiral, oblique, comminuted, and segmental. Finally, the classification should include a description of the soft tissue status of the limb, utilizing the classifications of Tscherne and Gotzen7 for closed fractures and Gustilo and Anderson8 for open fractures.
Indications for Surgical Treatment
Failure to Maintain Appropriate Alignment
Closed treatment can be expected to result in union in over 90% of cases. However, surgical treatment of these fractures is indicated in specific instances. Nonoperative treatment that fails to maintain reduction within accepted parameters should result in a change to surgical treatment. Klenerman9 showed that humeral angulation of up to 20 degrees in the anteroposterior (AP) plane and 30 degree in varus or valgus and up to 3 cm of shortening are well tolerated.
Open Fractures
Fractures with communication to the environment through a traumatic skin lesion should be managed operatively, with thorough debridement of all devitalized soft tissue and bone, and stabilization of the fracture. The importance of skeletal stability in the setting of open fractures should be appreciated for the role the stability plays in protecting the soft tissue from further injury and allowing better, faster recovery of the injured extremity.
Associated Articular Injuries
Diaphyseal humerus fractures associated with intraarticular fractures of the shoulder or elbow that require internal fixation should be stabilized at the same time (Fig. 15.5). These fractures could either be a diaphyseal fracture that extends into the adjacent joint, or a segmental humerus fracture that includes a diaphyseal fracture and a separate intra-articular shoulder or elbow fracture. Following fixation of the articular component of the fracture, postoperative care should include early mobilization of the joint, for which a stable humeral diaphysis is necessary. Failure to stabilize the humeral shaft prevents this mobilization and results in increased incidence of joint stiffness.
Neurovascular Injuries
Radial nerve injuries are the most common nerve injury associated with humeral shaft fractures, with a reported incidence ranging from 1.8 to 34%.10–13 Most primary and secondary radial nerve palsies associated with a humeral shaft fracture are due to neurapraxia and resolve spontaneously. Therefore, there is no consensus about which lesions might demand open exploration. Radial nerve lesions associated with fractures of the distal third of the diaphysis with a longitudinal or spiral component (the HolsteinLewis fracture) are an example of an instance where operative intervention might be considered. In this fracture pattern, the nerve may be lacerated or impaled by a sharp spike of bone, or trapped between the fracture fragments.10 In contrast, most fractures of the middle third of the humerus are more likely to result in a bruised or contused nerve when there is nerve dysfunction.14 In general, excellent results following conservative treatment of radial nerve lesions associated with humeral shaft fractures have been reported.12,13
One of the most controversial indications for operative intervention is the iatrogenic radial nerve palsy following closed manipulation, especially in the fractures of the distal third of the shaft with a long, spike-type configuration. Although these lesions are commonly said to require operative intervention, it has been shown that the vast majority of secondary radial nerve palsies also recover spontaneously.15 Finally, it has been shown that radial nerve deficits in open humeral shaft fractures are often due to nerve laceration.16 A final, but very subjective, finding is the presence of a gap in an otherwise benign fracture pattern with a nerve lesion; in such a case the gap may be evidence of nerve interposition (Fig. 15.6).
Vascular injuries in the setting of humeral shaft fractures are more commonly associated with penetrating trauma.17 Surgical stabilization of the extremity is necessary to provide a stable setting for the vascular repair to function without kinking or being stretched because of lack of skeletal stability. Whenever possible, skeletal stabilization should be completed prior to vascular repair or grafting for this reason. Cooperative multidisciplinary management of these cases is necessary.
Surviving the Night
Diaphyseal humeral fractures rarely require acute or urgent treatment. Emergent treatment is necessary in situations with open fractures, particularly with bone loss and radial nerve injuries. Initial stabilization may be accomplished with the use of a temporary external fixator, followed by definitive fixation and bony reconstruction.
Safe zones in the proximal and distal segments allow placement of external fixator pin placement while minimizing risk of injury to neurovascular structures. At the level of the humeral head, the safe zone is located lateral to the intertubercular groove, with the pin passing through the deltoid. The proximal-most pin should be directed from an anterolateral to posteromedial direction, starting lateral to the intertubercular groove, or transversely from direct lateral to medial. A second, more distal pin may be placed in the proximal segment just above the level of the deltoid tuberosity. This pin also traverses the deltoid. The anterior limit of this pin is the cephalic vein in the deltopectoral groove, and the posterior limit is the transverse plane of the humerus.
Fixation of the distal fragment including the elbow may be achieved with half pins directed from posterolateral to anteromedial. At the level of the distal one third of the humerus, the radial nerve is located lateral to the humerus, so a pin directed from a posterior or posterolateral direction through the triceps may be placed safely. A second, more distal pin in the distal fragment may be placed just posterior to the lateral epicondyle, directed anteromedially (Fig. 15.7).
With two pins in the distal fragment and two pins in the proximal fragment, the external fixator is constructed to allow maintenance of the soft tissues at the appropriate length, facilitating later bony and soft tissue reconstruction.
In instances in which the radial nerve is transected or when there is segmental loss of the nerve, the nerve ends should be identified at the time of initial wound management and tagged to allow easier identification at the time of repair, grafting, or reconstruction.
Initial wound management should focus on debridement of devitalized and contaminated tissues while preserving any viable bony segments. Application of antibiotic-impregnated beads and formation of a bead pouch can be utilized in situations where there are large amounts of soft tissue loss or gross contamination. Alternatively, negative-pressure wound vacuum treatment may facilitate wound cleansing and eventual wound closure. Thorough irrigation with saline and early administration of intravenous antibiotics minimizes the risk of development of infection.
Floating Elbow Injuries
Forearm fractures associated with humeral shaft fractures are optimally treated with surgical stabilization of all fractures to allow early mobilization of the extremity (Fig. 15.5).18,19 Failure to stabilize one or both fractures would require prolonged immobilization and potentially result in elbow and shoulder stiffness.
Impending Pathological Fractures
Pathological fractures of the humerus are a significant source of pain and disability for patients with metastatic disease or metabolic bone disease, and account for 8% of all humerus fractures.1 Impending fractures of the humerus can be stabilized by multiple operative techniques. Stabilization should be considered when 50 to 75% of the bone is destroyed by the lesion as evaluated on biplanar radiographs.20 Multiple factors should be considered when choosing to perform prophylactic fixation of humeral lesions, including the size of the lesion, the nature of the lesion (lytic vs blastic vs mixed), and the patient′s symptoms.21 Combined internal fixation and external beam radiation is effective in providing pain relief, as well as a stable limb, which will enable function. Internal fixation can be combined with cement augmentation to provide improved stability and subsequent pain relief.
Polytrauma Patients
Patients with multiple extremity fractures, including diaphyseal humerus fractures, are candidates for surgical stabilization of the humerus. In patients with head injuries and expected prolonged intensive care unit stays, rigid fixation aids in nursing care, transport, and limited mobilization. Patients with multiply injured extremities should be considered for fixation of their humerus when they will require the fractured arm for assistance with weight bearing on crutches or a walker, or for transfers. Internal fixation of humeral shaft fractures with a plate has enabled full weight bearing on the extremity with no increased risk of complication.22 In patients with bilateral upper extremity fractures, operative stabilization should be considered to hasten the ability to perform self-care and activities of daily living.
Surgical Treatment
General Concepts
The above section discussed several indications for surgical stabilization, such as open humeral fractures, bilateral humeral fractures, pathological fractures, ipsilateral humerus and forearm fractures (the floating elbow), and multiply injured patients where fixation assists patient care and mobilization. In contrast, an important element of nonoperative care is the ability of the patient to sit, and often sleep, in a semi-upright position that enables gravity to help reduce the fracture through the weight of the arm.
For patients with a fracture of the humerus and an associated lower extremity that requires restricted weight bearing, fixation of the humerus can provide such a patient with the ability to use crutches or other assistive devices. Tingstad et al22 note that others have estimated that the use of bilateral axillary crutches places up to 80% of body weight on the upper extremity, and documented that plate fixation is secure enough to provide these patients with the ability to use crutches when the principles of internal fixation are achieved. In addition, many orthopaedic trauma surgeons believe that it is possible to allow weight bearing after intramedullary nailing of the humerus when the fracture patterns are stable. An example would be intramedullary fixation of a transverse midshaft humerus fracture. Currently, evidence is lacking to recommend weight bearing after intramedullary fixation of comminuted fractures or other unstable fracture patterns, although published clinical series have suggested that patients treated with intramedullary nailing were able to use crutches or walkers within 2 weeks of surgery.23
Plate fixation and intramedullary nailing are the most common methods for the stabilization of humeral shaft fractures. External fixation is rarely used because of the risk of damaging neurovascular structures with pin placement and the subsequent problems of pin-track infections with motion of the shoulder and elbow.
The choice of plate fixation or use of an intramedullary nail is controversial and dependent on many factors, including the fracture pattern and location, associated soft tissue injuries and neurovascular injury, the presence of osteoporosis, associated ipsilateral injuries, and the method preferred by the operating surgeon.
Intramedullary nailing of humeral shaft fractures was not widely practiced until the advent of interlocking nails, which expanded the indications for nailing humeral shaft fractures and made the procedure more predictably successful. Currently, union rates seem to be comparable for plates and nails; the controversy exists because of the apparently increased risk of shoulder pain after antegrade nailing versus the benefits of using a closed technique. Proponents of plating also point out the risk of radial nerve injury from blind nail placement, whereas nailing advocates claim that the risk to the nerve is greater during open procedures. There have been several attempts to compare the relative advantages and problems experienced with the use of plate fixation as opposed to intramedullary nailing.24–27 Small, prospective, randomized trials and metaanalyses conclude that both plate fixation and intramedullary nailing achieve high and comparable rates of union. The major difference between the two methods has been in the complications that are specific to the two techniques, as well as a lower risk of complications when using a plate compared to an intramedullary nail.28
Surgical Techniques: Open Reduction and Internal Fixation with Plates
Patient Positioning
The choice of patient position depends on the approach chosen to expose the humeral fracture. Generally, the anterolateral approach necessitates supine positioning with a radiolucent arm board attached to the table. In the setting of polytrauma, the supine position is preferred, especially when there is a spinal injury or if spine clearance is not complete. The patient can be positioned with the head turned away from the operative side slightly to facilitate draping as well as protection from misplaced instruments on the facial area during the procedure. The endotracheal tube is preferably placed so that it exits on the far side of the mouth from the operative side. The patient should be positioned with the torso as close to the arm board as possible. A small bump placed under the scapula will slightly elevate the shoulder and facilitate access for draping the arm to the shoulder. Shoulder abduction of approximately 60 degrees enables exposure of the humeral shaft. Use of a nonsterile tourniquet makes it difficult to adequately approach humeral fractures in the middle or proximal third, so if a tourniquet is desired, a sterile one is preferable in these circumstances.
Lateral decubitus positioning is useful when a lateral or posterior approach is used. The patient can be supported with a beanbag, and a large bump of linen can be taped to the patient′s chest to act as an operative surface. Alternatively, a popliteal roll leg holder may be positioned in the antecubital area and fastened to the table to provide a similar working surface. When positioning the patient in the lateral position, the torso should be brought toward the edge of the table as far as safely possible. The shoulder is abducted 90 degrees for maximal exposure.
The posterior approach is easily accomplished with the patient in the prone position. The shoulder is abducted 90 degrees and in neutral extension. Chest rolls appropriately positioned enable a small amount of forward flexion of the shoulder to prevent excessive stretch of the brachial plexus. A radiolucent arm board attached to the operative table provides an adequate working surface and still enables intraoperative fluoroscopy use.
Radiographic Imaging
Preoperative radiographic evaluation should include two views of the entire humerus in orthogonal planes. This is typically accomplished by an AP and lateral X-ray of the humerus. Many special views can be used for proximal and distal humeral imaging, but the humeral diaphysis is best viewed with these two simple views.
Whereas much of the humerus can be reduced and secured under direct visualization, intraoperative fluoroscopy is a useful tool for almost every humerus fracture. Imaging can aid in judging reduction as well as hardware position and screw placement and length. In the lateral decubitus position, the C-arm is brought in from the front side of the patient in the vertical direction. This arrangement will produce an AP view of the humerus, and a lateral view can be obtained by externally rotating the shoulder 90 degrees. Imaging in the supine or prone position is performed by keeping the C-arm in a vertical position and rotating the shoulder to obtain AP and lateral images through the radiolucent arm table.
Surgical Approaches
Anterior Approach
The anterolateral approach (Fig. 15.8) is commonly used for open reduction and internal fixation (ORIF) of the humeral shaft. This approach provides access to the entire diaphysis of the humerus and can be extended both proximally and distally. The approach is made lateral to the palpable mass of the biceps and brachialis muscles. The brachialis is dissected to the bone at a point just anterior to the lateral intermuscular septum. Dissection and mobilization of the radial nerve are not mandatory with this approach, although some care should be taken to avoid injury to the lateral antebrachial cutaneous nerve in the distal portion of the incision.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
