Humeral Shaft Fracture Stabilization with Elastic Nails
Chapter 16
Humeral Shaft Fracture Stabilization with Elastic Nails
Nathan W. Skelley
J. Eric Gordon
DEFINITION
Humeral shaft fractures comprise approximately 2.5% of all traumatic fractures in children.11
Nearly all humeral diaphyseal fractures in children can commonly be treated nonoperatively with bracing and sling support.9, 10
Titanium elastic nails can be used to stabilize selected humeral shaft fractures in children and adolescents from the distal metaphysis to the proximal humeral physis.
ANATOMY
Proximally, the neurovascular bundles are located near the axilla, however, distally, the ulnar nerve and radial nerve pass in proximity to the medial epicondyle and lateral condyle, respectively (FIG 1).
If antegrade nails are to be used, the course of the axillary nerve is important as it passes lateral to the proximal humerus from posterior to anterior approximately 3.5 cm distal to the greater tuberosity in adults.5
PATHOGENESIS
The humerus is initially made of woven bone that is gradually replaced by stronger lamellar bone during childhood.
This developmental transition makes the bone prone to fracture with direct impact and falls on outstretched arms.
An increasingly active pediatric population and the increased prevalence of motorized sports has led to an increase in humeral shaft fractures.1, 3, 6, 11
Clinical examination and radiographs can assist in characterizing the injury mechanism.
NATURAL HISTORY
Most humeral shaft fractures are amenable to nonoperative treatment.
In young children, moderate shortening (<3 cm) is well tolerated as is angulation up to 30 degrees for fractures in the proximal third, 25 degrees in the middle third, and 20 degrees in the distal third.3, 6
Fractures in the distal one-fourth humeral metaphysis are more sensitive to angulation and should be maintained within 10 degrees of anatomic alignment.
PATIENT HISTORY AND PHYSICAL FINDINGS
Most humeral shaft fractures are identified by the common complaints of pain, discomfort, or disuse. In pediatrics, the patients may not clearly verbalize the pain. Therefore, discomfort or disuse of the extremity should encourage further evaluation.
High-energy trauma is commonly associated with shortening and angulation of the upper extremity. Soft tissue injuries are also common findings (FIG 2).
Humeral shaft fractures are commonly the result of mild trauma in the presence of pathologic lesions such as unicameral bone cysts.8
A complete distal neurologic and vascular examinations should be performed and documented to verify the patient is neurovascularly intact. In younger children, a careful motor examination is essential, as the sensory examination can be unreliable.
Examination with careful palpation of the remainder of the extremity should be performed because ipsilateral forearm, wrist, or shoulder injuries are not unusual (see FIG 2).
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FIG 1 • Anatomy of the humerus with important neurovascular structures shown.
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FIG 2 • Anteroposterior and lateral radiographs of the humerus in a 6-year-old girl demonstrating a displaced diaphyseal fracture sustained in a rollover motor vehicle accident. The patient also sustained an ipsilateral radius fracture, multiple head injuries, and ipsilateral tibia fracture.
Plain radiography is usually adequate to make a definitive diagnosis, although magnetic resonance imaging (MRI) can be occasionally helpful in distinguishing pathologic fractures through benign and malignant lesions.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Two views (internally and externally rotated) of the humerus are usually sufficient to diagnose a humeral shaft fracture.
The joint above and below should be clearly visualized.
Concern on physical examination for injuries to the shoulder, forearm, or wrist should be evaluated by appropriate radiographs.
DIFFERENTIAL DIAGNOSIS
Pathologic fracture Benign or malignant tumor
NONOPERATIVE MANAGEMENT
Humeral shaft fractures commonly do well functionally and cosmetically from nonoperative treatment. Functional bracing, coaptation splints, hanging arm casts, or sling immobilization are common treatments. Younger children have profound remodeling potential and can successfully remodel fractures with significant
angulation up to 45 degrees.
Authors have recommended that older children should be reduced to less than 30 degrees for proximal third, less than 20 degrees for middle third, and less than 15 degrees for distal third shaft fractures before proceeding with nonoperative treatment.3, 6
SURGICAL MANAGEMENT
Surgical stabilization of humeral shaft fractures is indicated in certain scenarios including the following: Open fracture
Inability to maintain adequate alignment by closed mean
Ipsilateral forearm fractures (floating elbow) Closed head injuries to simplify nursing care
Polytraumatized patients, particularly with lower extremity fractures to facilitate mobilization out of bed by allowing upper extremity weight bearing6
The main goal of elastic nailing in humeral shaft fractures is to create a biomechanical stable reduction with axial, angular, translational, and rotational stability.
This is typically accomplished with two nails inserted through the metaphysis using a three-point application about the diaphyseal fracture site.
The nails are contoured by hand or with a plate-bending press to place the apex of the nail at the fracture site.
Elastic nailing is ideal for transverse and minimally comminuted fractures. Oblique diaphyseal fractures and unstable comminuted fractures can also be treated with flexible nailing because mild to moderate shortening rarely causes clinical problems.
Plate fixation requires a large incision, extensive dissection, and often requires exposure of neurovascular structures.
Preoperative Planning
A decision should be made between antegrade and retrograde nailing techniques.
Most fractures are treated with retrograde nailing. This technique allows stabilization of distal, midshaft, and proximal fractures with excellent stability.
The primary indication for antegrade nailing is soft tissue injury about the elbow requiring secondary procedures to obtain coverage.
Fractures in the distal and middle thirds of the humerus are best stabilized using retrograde nails placed from the medial and lateral sides of the elbow. Fractures in the proximal third of the humerus can be stabilized using two nails placed from the lateral side of the elbow, obviating the risk of ulnar nerve injury. FIG 3 shows incision sites and nail starting points.
A fluoroscopic image intensifier with a radiolucent hand table is necessary to follow nail progression in the humerus and to confirm reduction with both antegrade and retrograde techniques.
The nail selected for fixation is commonly about 40% of the narrowest diameter (isthmus) of the humerus. Most fractures can be stabilized with either 3.0- or 3.5-mm nails. If increased rigidity is needed, stainless steel nails can be used.
As in other applications of flexible nails, if two nails are being placed, the same size should be used for both nails to prevent asymmetric forces.
Positioning
The patient is placed supine on a radiolucent table with an arm table on the affected side (FIG 4). The affected upper extremity is abducted approximately 90 degrees.
The upper extremity is draped free. The shoulder area should be squared off using towels leaving as much of the shoulder surgically accessible as possible to facilitate changes in operative approach from retrograde to antegrade approaches in the event of intraoperative problems.
A tourniquet is not typically needed for elastic nailing. If an open reduction of the fracture is necessary, a sterile tourniquet can be used.
Approach
Placement of retrograde nails can be nearly percutaneous.
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FIG 3 • A,B. Incision locations are shown for antegrade (A) and retrograde (B) approaches for humeral nailing.
C. The crosshairs mark the general starting points for either antegrade (1) or retrograde (2) humeral nails.
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FIG 4 • Patient prepped and draped in the supine position and with the arm on a radiolucent hand table.
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TECHNIQUES
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Antegrade Flexible Intramedullary Nailing
Exposure and Drilling
Fluoroscopy is used to localize the starting point and incision.
A 1- to 2-cm longitudinal incision is made laterally over the shoulder just distal to the lateral edge of the acromion.
Dissection is performed with tenotomy scissors or electrocautery down to the level of the humeral metaphysis, incising the deltoid and the rotator cuff longitudinally in line with their fibers.
The metaphysis is entered with a 3.2- or 4.5-mm drill approximately 2 cm lateral to the glenohumeral joint articular surface. Alternatively, an awl can be used to create a cortical opening for the nail.
Once the cortex is breached, the drill or awl should be angled obliquely to the fracture site to facilitate nail entry into the canal.
Nail Placement
The implants are selected and the first nail is prebent and passed down the intramedullary canal to the fracture site. Use the image intensifier periodically to verify correct nail placement in the canal.
The nail is passed by attaching the nail inserter 5 to 10 cm from the skin to provide for better control during impaction with a hammer. When the inserter is close to the skin, the device should be released, moved back on the nail, tightened again, and impacted. This process is repeated until the nail is in an appropriate position.
The nail should pass easily in the intramedullary canal when hammering. If the nail does not pass easily, consider these common issues: nail orientation in the canal, insufficient contour of the nail tip, poor choice of nail diameter, and cancellous or cortical blockage.
The fracture is most often reduced closed, and the nail is driven across the fracture site and into the distal portion of the humerus. The nail is impacted into the supracondylar region either medially or laterally.
A second nail of the same size is then selected and prebent.
To avoid producing angulation at the fracture site, it is important to choose nails of the same diameter.
Again, a drill is used to enter the proximal humeral metaphysis adjacent to the initial starting point. The nail is passed down the medullary canal, across the fracture site, and impacted into the distal humerus opposite the first nail.
An alternative acceptable technique preferred by some surgeons is to pass both nails to the fracture site, then reduce the fracture and pass both nails across the fracture site and advance them distally together into final position.
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Retrograde Flexible Intramedullary Nailing
Exposure
A 1- to 2-cm longitudinal incision is made over the lateral epicondyle of the distal humerus. Dissection is carried out down to the epicondyle bluntly (TECH FIG 1).
Drilling
The bone is entered with a 3.2- or 4.5-mm drill at the level of the epicondyle.
Under image intensification, the drill is passed up through the lateral column of the humerus and into the medullary canal.
It is important to pass the drill fully through the lateral column and into the medullary canal, as the bone in the lateral column is very dense, and if the drill is not passed completely into the medullary canal, passing the nail can be extremely difficult (TECH FIG 2).
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TECH FIG 1 • A,B. Fluoroscopy is used to localize the starting point and incision. C. The subcutaneous tissues are gently spread until contact is made with the humerus.
It is essential that frequent anteroposterior and lateral images of the elbow be obtained while drilling, as perforation of the cortex with the drill leading to inability to pass the nail can happen easily.
First Nail Placement
A nail is then selected, prebent, and passed up the lateral distal humerus to the fracture site (TECH FIG 3). The fracture site is reduced manually and maintained with traction.
The nail is passed across the fracture with a hammer impacting the nail inserter device. The nail may need to be advanced and retracted several times to successfully pass the fracture site and remain in the intramedullary canal. Use the image intensifier to confirm placement.
The nail is impacted into the proximal humeral metaphysis either laterally or medially.
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TECH FIG 2 • Fluoroscopy is used to find the starting point and confirm drill placement within the medullary canal.
Second Nail Placement
The second nail can be placed either laterally or medially depending on the location of the fracture. Usually, a lateral placement is selected if the fracture is in the proximal third of the humerus.
If a second lateral nail is to be placed, a second entry into the distal humerus is made 3 to 5 mm proximal to the initial starting point, and again, the drill is passed up the lateral humeral column into the medullary canal.
A medial placement is selected if the fracture is in the middle or distal third of the humerus to enhance construct stability.
If a medial nail is required, placement is through the medial epicondyle.
Ulnar nerve subluxation with the elbow in flexion should be assumed because of the high rate of
subluxation in children and adolescents.2 Therefore, the elbow should be kept extended throughout the process of entering the medial epicondyle.
With the elbow extended, a 1- to 2-cm incision is made over the medial epicondyle and the ulnar nerve is visualized. It is not necessary to dissect the nerve free as long as it can be visualized and protected during drilling and nail placement (TECH FIG 4).
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TECH FIG 3 • A. The nail is prebent to assist with placement. B,C. The nail is secured with nail inserter device and placed in the drilled site. The nail inserter device is hammered through the humerus while the fracture site is reduced with manual traction. D. The passage of the nail should be monitored and corrected on fluoroscopy to properly reduce the fracture. The nail should be partially removed and redirected if proper reduction is not obtained.
A 3.2- or 4.5-mm drill is passed up the medial column of the humerus into the medullary canal. Again, frequent imaging checks of the elbow are necessary to assure appropriate drilling of the medial column.
A nail the same size as the initial nail is then selected and passed through the entry site, either laterally or medially. The nail is driven across the fracture site and impacted into the proximal humeral metaphysis opposite the initial nail.
As with the antegrade technique, an alternative acceptable technique preferred by some surgeons is to pass both nails to the fracture site, then reduce the fracture and pass both nails across the fracture site and advance them together proximally into final position.
Completion
The nails are then cut off, capped, and impacted into the bone. End caps are particularly helpful in this area to minimize
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discomfort with elbow motion and if used should be placed prior to impacting the nails into the bone (TECH FIG 5).
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TECH FIG 4 • A. The ulnar nerve is identified through a medial incision. B. Retractors are used to protect the ulnar nerve during drilling and nail placement. C,D. Fluoroscopy is used to confirm correct nail placement and fracture reduction.
Once the nails have been placed into position, final images should be taken with the image intensifier. The fracture site is also checked to ensure that the fracture site is not distracted.
If distraction is present, the elbow can be gently impacted with the palm of the hand to compress the fracture site. If this is done, it is important to check the nails for prominence prior to closure.
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TECH FIG 5 • A. The excess nail is cut near the skin. B. The end cap has been placed after bending the delivery device to break off the end cap. End caps are placed to prevent soft tissue injury from the cut nail. C. The end cap and nail are tapped under the soft tissues.
The incisions are irrigated with normal saline, and a standard layered closure is performed.
We use 2-0 absorbable sutures for the deep dermal layer and 3-0 absorbable sutures for the subcutaneous closure.
A dermal adhesive or Steri-Strips can be used to support the skin closure.
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Indications ▪ Most humeral shaft fractures can be treated nonoperatively.
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adequate space to place the prebent nail. Attempts to drive the nails through the columns without completely drilling are difficult because of the dense bone and incompletely developed medullary canal in the distal portions of the humerus.
Fracture ▪ Remember, if the nail ceases to advance, rotation of the nail often will facilitate fixation passage and prevent a cortical breach during impaction.
Difficulty ▪ The humerus commonly reduces easily with manual traction. in ▪ If the fracture cannot be reduced closed, a small open approach to the fracture site reduction allows removal of tissue preventing reduction.
Skin ▪ Skin irritation is decreased with nails that are flush with the metaphysis. This is irritation facilitated by using a larger drill than might otherwise be anticipated. Except in very small patients, a 4.5-mm drill is used to open the medullary canal during both antegrade and retrograde applications.
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POSTOPERATIVE CARE
A long-arm posterior splint or cast is often applied for comfort in the immediate postoperative setting. This is removed in the first 1 to 2 weeks postoperatively.
Weight bearing can be started immediately if necessary in length-stable fractures. A platform type walker or crutch is often helpful for the patient.
If appropriate for ipsilateral injuries, motion may be started 10 days postoperatively. A sling may be used for comfort during the first 10 to 14 days.
If additional protection is desired, a fracture brace can be used to add additional stability.
Patients should be followed for at least 6 months postoperatively until solid bony union and then as needed.
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FIG 5 • A,B. Radiographs at 6 weeks postoperatively demonstrate final nail fixation, improved alignment, and fracture healing in the patient in all the technique figures. C,D. Postoperative radiographs of the patient in FIG 2 show humeral nailing with elastic nails.
OUTCOMES
Patients with humeral fractures requiring stabilization at our institution have ranged from 4 to 16 years of age at the time of surgery. All of these fractures have gone on to union in acceptable alignment (FIG 5).6
Retrograde nailing has been used in most patients (84%) and antegrade nailing was used in patients with significant soft tissue trauma about the elbow. Some of these patients had severe trauma with a number (23%) having open Gustilo class III fractures.6, 7
Nearly all patients have regained normal motion at the shoulder and elbow.
The technique of nail placement is familiar to most surgeons who frequently treat pediatric fractures and requires little
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special equipment, but there are treatment details that are unique to the humerus. Collapse at the fracture site can cause nail migration and nail prominence under the skin.
Stainless steel nails have demonstrated satisfactory results with humeral fixation and provide increased rigidity. They may result in a lower incidence of migration.4
COMPLICATIONS
Nail migration caused by fracture shortening in the first 6 weeks postoperatively has been the most frequent complication.6
There have been no postoperative wound infections, delayed unions, refractures, or malunions reported to our knowledge.
Motion deficits postoperatively are rare and have not caused functional deficit in any patients.
REFERENCES
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Beaty JH. Fractures of the proximal humerus and shaft in children. Instr Course Lect 1992;41:369-372.
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Calfee RP, Manske PR, Gelberman RH, et al. Clinical Assessment of the ulnar nerve at the elbow: reliability of instability testing and the association of hypermobility with clinical symptoms. J Bone Joint Surg Am 2010;92(17):2801-2808. doi:10.2106/JBJS.J.00097.
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Caviglia H, Garrido CP, Palazzi FF, et al. Pediatric fractures of the humerus. Clin Orthop Relat Res 2005; (432):49-56.
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Chitgopkar SD. Flexible nailing of fractures in children using stainless steel Kirschner wires. J Pediatr Orthop B 2008;17(5):251-255. doi:10.1097/BPB.0b013e328306898d.
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Gardner MJ, Griffith MH, Dines JS, et al. The extended anterolateral acromial approach allows minimally invasive access to the proximal humerus. Clin Orthop Relat Res 2005;(434):123-129.
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Gordon JE, Garg S. Pediatric humerus fractures: indications and technique for flexible titanium intramedullary nailing. J Pediatr Orthop 2010;30:S73-S76. doi:10.1097/BPO.0b013e3181bbf19a.
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Gustilo RB. Interobserver agreement in the classification of open fractures of the tibia. The results of a survey of two hundred and forty-five orthopaedic surgeons. J Bone Joint Surg Am 1995;77(8):1291-1292.
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Knorr P, Schmittenbecher PP, Dietz HG. Elastic stable intramedullary nailing for the treatment of complicated juvenile bone cysts of the humerus. Eur J Pediatr Surg 2003;13(1):44-49. doi:10.1055 /s-2003-38288.
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Sarmiento A, Kinman PB, Galvin EG, et al. Functional bracing of fractures of the shaft of the humerus. J Bone Joint Surg Am 1977; 59(5):596-601.
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Sarmiento A, Latta L. The evolution of functional bracing of fractures. J Bone Joint Surg Br 2006;88(2):141-148. doi:10.1302/0301-620X.88B2.16381.
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Shrader MW. Proximal humerus and humeral shaft fractures in children. Hand Clin 2007;23(4):431-435,
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