Fractures of the Femoral Shaft

History and Physical Examination

The history is important, as treatment varies depending on the mechanism of injury and its associated level of energy. The treatment of a fracture resulting from a high-energy motor vehicle accident is approached differently than a pathologic or stress fracture. High-energy fractures are more likely to have associated soft tissue injury. The presence of significant soft tissue injury or periosteal stripping should influence the treatment options because these injuries are less amenable to closed treatment.

A suspicious history may lead one to investigate nonaccidental trauma as a cause of the fracture. Differentiating between nonaccidental and accidental trauma is anxiety provoking for both the physician and the caregiver. The well-being of the child is paramount, yet preserving a working relationship with the caregivers can be done with care and time. Understanding the demographics and different disease processes responsible for nonaccidental trauma can assist in narrowing the differential diagnosis. That said, the current AAOS clinical practice guideline recommends that children younger than 36 months of age with a diaphyseal femur fracture be evaluated for child abuse. The injury plausibility method helps tabulate historical data into the likelihood of injury from falling from stairs, a common occurrence, yet also a common false reason given to explain child abuse.

History can assist with the identification of accompanying injuries. For instance, identifying the occurrence of a pedestrian versus motor vehicle accident alerts one to the possibility of the Waddell triad, which describes the associated head injury, intrathoracic or abdominal injury, and femoral fracture that can occur from such trauma. The Waddell triad is actually less common than originally thought, and the more common ipsilateral upper extremity and pelvic injuries should be closely evaluated.

The physical examination of an injured, conscious child always begins by gaining the patient’s trust and reassuring the family. A reliable examination of the injured extremity can begin only after a nonthreatening relationship is established. Careful inspection for obvious deformities or swelling is performed, and any soft tissue defects are measured and recorded. Careful palpation of the nontraumatized areas is done to identify secondary injuries. A motor and sensory examination is performed, and peripheral pulses are documented. The examination of the injured extremity is compared with the status of the uninvolved extremity. Any difference warrants further evaluation.

In patients with ipsilateral fractures proximal and distal to the knee (floating knee), it is imperative to evaluate the vascular status of the extremity more carefully. Hard signs of vascular injury are obvious and include pulsatile hemorrhaging, an expanding hematoma, a palpable thrill or audible bruit, or a pulseless limb. More subtle physical clues include unequal pulses, decreased two-point discrimination distal to the fracture, or a nonpulsatile hematoma. However, physical examination alone is not reliable enough to preclude further workup in high-risk injuries. An arterial pressure index (API) or an ankle-brachial index (ABI) can be used in the emergency department as a screening test. The API is calculated by placing one blood pressure cuff distal to the lower extremity injury, and another is placed on an uninjured upper extremity. A Doppler probe is used to determine the systolic pressure of both extremities. The systolic arterial pressure in the injured extremity is divided by the systolic pressure in the unaffected upper extremity to calculate the API. A value less than 0.9 warrants additional radiographic imaging.

Assessment of the injured portion of the thigh is reserved for last and should be performed gently. Traction, reduction, or wound probing should be minimized in patients likely to undergo surgery. These maneuvers should be conducted in the operating room when possible. The exception is in patients whose deformity and pain can be relieved by manipulation and splinting. If manipulation is performed, serial neurovascular checks should be conducted.

It is imperative during the initial assessment of femoral fractures to search for accompanying injuries. In patients with isolated femoral shaft fractures, hemodynamic insufficiency is rare, and volume support is not customarily required. If a patient is seen with hypotension, hypovolemia, or anemia, further investigation must be performed to identify another cause for the bleeding, other than the femoral fracture. Typically, only patients with additional trauma have significant decreases in both hemoglobin concentrations and hematocrit levels compared with patients with isolated femoral fractures. An obvious decrease in hematocrit or hemoglobin concentration in a child with a femoral fracture nearly always indicates additional injury.

In high-energy trauma, examination is dictated by the Advanced Trauma Life Support protocol. The initial assessment is directed to the airway, breathing, and circulation, and attention to any limb injury is focused on circulatory (hemorrhage) control from open injuries. All limbs are stripped of clothing during the initial examination. Once the patient is stabilized, a secondary survey can be conducted. The limbs are evaluated for further injury by examination for bruising or deformity and palpation for tenderness, crepitus, diminished pulses, and limited joint range of motion. If the patient is stable, further radiographic imaging can then be performed if additional fractures are a concern.

Ipsilateral intraarticular knee injuries are a very common (16%–70%) associated injury with diaphyseal femoral fractures in the adult population. The pediatric incidence is unknown, but one should have increased suspicion for these injuries in older children and adolescents. Cruciate and collateral ligament tears and meniscal and osteochondral injuries can occur. Examination for intraarticular injuries is difficult in the acute care setting. A complete ligamentous examination is most easily obtained intraoperatively after stabilization of the femoral fracture and postoperatively by serial evaluation. Magnetic resonance imaging (MRI) or arthroscopy may be warranted.

Imaging

High-quality anteroposterior (AP) and lateral plain films that include both the hip and knee joints are generally the only radiographic studies required to diagnose and treat pediatric femoral shaft fractures. The advent of the Picture Archiving and Communication System has greatly facilitated measurement of intramedullary canal size and femoral length.

Many practitioners advocate traction films for evaluating stability and predicting treatment outcomes after femoral fractures. The “telescope test” described by Thompson and colleagues predicts that unacceptable final shortening of 25 mm is 20 times more likely if 30 mm of initial shortening or more was identified during the test. The telescope test is a gentle compressive force applied manually across the fracture site. Radiographs are made on standard cassettes with the x-ray beam perpendicular to the fracture site so that maximum overriding of the fracture fragments can be documented. Interestingly, a resting radiographic overlap was not predictive of the final outcome in this study.

Excessive shortening is the result of associated soft tissue injury. Often, history and physical examination can predict the likelihood of excessive shortening. Documentation of excessive shortening may indicate the use of more invasive treatment methods.

Computed tomography is helpful in the evaluation of physeal or periarticular fractures but is not required in isolated femoral shaft fractures. A bone scan may be useful for the detection of suspected stress or pathologic fractures but is unlikely to yield helpful information in a traumatic fracture. Bone scans have been described as an adjuvant modality for diagnosis of orthopedic injuries missed in the initial screening of multiply injured patients with head injuries.

MRI is valuable for assessment of intraarticular pathology, stress fractures, and pathologic lesions. Ipsilateral epiphyseal, ligamentous, meniscal, and osteochondral pathology are relatively common. In particular, one should be concerned about osteochondral injury or bone bruises in patients with persistent knee pain after a healed diaphyseal femoral fracture.

Vascular compromise should be evaluated in an expeditious manner. Arteriograms are the historical gold standard for investigating vascular insufficiency. Assessment with duplex ultrasound, ABI, or both may be useful for determining the need for an arteriogram in equivocal cases. Identification of an arterial injury is more likely to occur when the physician suspects and evaluates for a vascular injury. Physical examination alone has proved inadequate for diagnosing vascular compromise.

Classification

Classification systems provide descriptive information and serve as a basis for selecting optimal treatment, predicting the outcome, and comparing results of various treatment modalities. Maurice E. Müller believed this general theorem and stated that “a classification is useful only if it considers the severity of the bone lesion, and serves as a basis for treatment and for evaluation of the results.” He subsequently developed the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification, which is commonly used in describing adult fractures as combined in the Orthopaedic Trauma Association-AO classification system. In 2007, the AO Pediatric Comprehensive Classification of Long Bone Fractures was developed and the lower extremity component validated in 2017. The femoral shaft fractures are classified as category 32-D, with subcategories 4.1, 4.2, 5.1, and 5.2 ( Fig. 12.2 ).

Though validated, the AO classification system is not commonly used to describe pediatric femoral shaft fractures clinically. Rather, fractures are more commonly classified according to (1) cause, (2) soft tissue integrity, (3) anatomy, and (4) fracture pattern.

The mechanism, chronicity, and other contributing causal factors responsible for fracture contribute to nomenclature. Most fractures can be relegated to high- or low-energy mechanism. Pathologic fractures are considered low energy and are the result of tumors, metabolic disorders, or other processes resulting in abnormal bone biomechanics. Stress fractures occur secondary to repetitive and chronic overuse syndromes. Nonaccidental fractures are caused by intentional harm. Accidental trauma is typically associated with a high-energy mechanism, such as from a motor vehicle accident.

The status of the soft tissue envelope plays an important role in the treatment of femoral fractures and likewise contributes to classifying these fractures. Fractures are considered open if the bone communicates with a wound in the skin and closed if the skin is intact. Ballistic open wounds warrant close attention. In particular, “wadding,” which is the barrier between the pellets and gunpowder in shotgun shells, must be accounted for. It is important to note that injuries with intact skin can also have compromised soft tissues. The soft tissue envelope and thick periosteum play a significant role in pediatric fracture stability, and this is inversely proportional to the age of the child. Excessive soft tissue injury and periosteal stripping result in increasing instability and typically require more invasive fixation methods. Bicycle spoke injuries, wringer injuries, and other high-energy mangled extremities are examples where there is extensive soft tissue envelope injury.

Classification by anatomic location of the femoral fracture has important implications for treatment. Femoral shaft fractures are considered to be subtrochanteric, diaphyseal, or supracondylar. Subtrochanteric femoral fractures present unique problems in fracture management. Fractures in this region have limited capacity to compensate for malalignment, and the strong deforming muscle forces place the proximal fragment in a flexed, abducted, and externally rotated position. This malalignment makes maintenance of fracture reduction difficult. The definition of a pediatric subtrochanteric femoral fracture is controversial. Pombo and Shilt advocated that a fracture that occurs within 10% of the total length of the femur below the lesser trochanter should be classified as subtrochanteric. There are other published definitions that do not accommodate the great variability in pediatric femoral length. However, a definition that takes into account the wide range of femoral lengths in the pediatric population may be the most accurate and has been found to be useful. Supracondylar femoral fractures historically presented similar problems with definition and management. Butcher and Hoffman defined a supracondylar femoral fracture as one in which the distance from the fracture to the knee joint center was equal to or less than the width of the femoral condyles. Hyperextension of the distal fragment is common secondary to forces from the gastrocnemius muscle. Although less common, a residual flexion deformity at the fracture site can result in interference with patellar tracking. Recognition of these difficult fractures from the more easily treated diaphyseal fractures is critical.

Finally, nomenclature detailing the fracture pattern provides further understanding of its inherent stability. Commonly described fracture patterns include simple transverse, short oblique, long oblique, long spiral, or comminuted. Simple and short oblique fracture patterns are considered “length-stable.” Long oblique, long spiral, and comminuted fracture patterns are considered “length-unstable.” Specifically, long oblique and comminuted fractures are defined as follows:

• Long oblique: The length of the obliquity is twice the diameter of the femur at the level of the fracture.

• Comminuted or multifragmentary: More than one continuous fracture is present, of which there are two types:

  • Butterfly or wedge: The two main fragments maintain some contact.

  • Complex: No contact is present between the two main fracture fragments.

This differentiation is critical because the method of treatment may need to be modified so that adequate stability is ensured for the specific fracture pattern.

Emergent Treatment

Early surgical stabilization of femoral shaft fractures in children has been shown to decrease hospital stay and intensive care unit stay without increased risk of pulmonary complications. Patients who are medically stable should undergo definitive treatment on their initial presentation. Polytrauma patients who are not medically stable enough to undergo definitive fixation can be treated with temporary external fixation or traction with conversion to intramedullary nailing within 2 weeks if their medical condition improves. Although the exact timing of operative management of open fractures is controversial, open fractures should be treated with early antibiotics, urgent irrigation and débridement, and temporary or definitive fracture fixation.

Indications for Definitive Care

The treatment of femoral shaft fractures has traditionally been based on chronological age ( Table 12.1 ). Although age may serve as one reasonable guideline, the large variance in patient morphometry and skeletal age precludes this demographic as the sole guide to treatment. Using age alone fails to address problems in children who are extremely large or small for their chronologic age. Hence, many treatment failures occur as a result of mismatching between the biomechanical demands of the fracture and the stability provided by a chosen treatment ( Fig. 12.3 ). For consistency purposes, the authors use an age-based approach, realizing that there is acceptable variability at each end of the age limits proposed to accommodate the aforementioned variance in patient morphometry.

Infants 6 months or younger with femoral shaft fractures can be treated in a Pavlik harness or spica cast. Neonatal fractures heal quickly in 2 to 3 weeks and remodel significantly. Pavlik harness treatment may be preferable secondary to the many reported disadvantages of spica casting.

Children 6 months to 5 years of age with fractures demonstrating less than 2 cm of shortening can be treated with early spica casting or traction with delayed spica casting. However, fractures with greater than 2 cm of shortening are unstable and may require an alternative treatment method, such as flexible intramedullary nailing, plating, or external fixation. Fractures are generally considered unstable because of the significant shortening or angulation at initial presentation. Either parameter can occur secondary to excessive soft tissue stripping or the nature of the bony injury, as both are indicative of high-energy injury. Typically, overriding of the fracture segments by 2 cm is an indirect measure of disruption of the periosteal sleeve. The telescope test (described in the “Imaging” section) can be used to determine fracture stability. Long oblique, long spiral, and comminuted fracture patterns are generally length-unstable. In unstable fractures, the authors prefer to use a submuscular plating technique because of the well-reported complications of external fixation.

Length-stable fractures of the femur in children 5 to 11 years of age can be treated with flexible intramedullary nailing. Children with femoral shaft fractures treated with flexible intramedullary nailing have been found to have less residual angular deformity, less leg length discrepancy, shorter hospitalization, earlier ambulation, earlier return to school, lower overall cost, better scar acceptance, and higher overall parent satisfaction than children treated with traction and spica casting. Earlier advancement to full weight-bearing, shorter time to regain full range of motion, earlier return to school, lower complication rate, and less residual malalignment have also been reported with flexible intramedullary nailing compared with external fixation. This technically simple, economic, safe modality of treatment can be used when the intramedullary canal size allows and should be used until it is no longer biomechanically sound to do so. Children who weigh more than 49 kg who are treated with titanium elastic nails are at increased risk of a poor outcome. Therefore, an alternative treatment option, such as plating or rigid trochanteric entry intramedullary nailing, should be used. Unstable fractures in this age group can be treated with stainless steel flexible intramedullary nails, plating, or external fixation.

Finally, children age 11 years to skeletal maturity can be treated with rigid trochanteric entry intramedullary nailing if the femoral canal is large enough to accommodate the nail. Rigid nailing has been used safely in the treatment of adult femoral shaft fractures for decades. This modality has also been shown to be successful in the pediatric population. One notable difference between rigid nailing in adult and pediatric patients is the risk of avascular necrosis of the femoral head. This complication results from injury to the posteriorly based blood supply to the femoral head in patients with open proximal femoral physes. A 2% risk of avascular necrosis of the femoral head has been associated with a rigid nail inserted at the piriformis fossa. The risk of avascular necrosis can be decreased with the use of a lateral trochanteric entry point. Modern pediatric rigid nails are inserted at the lateral aspect of the greater trochanter. Thorough knowledge of the technique is required before use of a rigid trochanteric entry nail in a skeletally immature patient is advised.

These guidelines based on chronological age are general recommendations. The specific characteristics of the fracture and patient’s body habitus must be considered. Individual circumstances always dictate fracture management.

Nonoperative Treatment