FEMORAL SHAFT

EPIDEMIOLOGY

The highest age- and gender-specific incidences of femoral shaft fracture are seen in males from 15 to 24 years of age and in females 75 years of age or older.

Femoral shaft fractures occur most frequently in young men after high-energy trauma and elderly women after a low-energy fall.

The bimodal distribution peaks at 25 and 65 years of age with an overall incidence of approximately 10 per 100,000 population per year.

ANATOMY

The femur is the largest tubular bone in the body and is surrounded by the largest mass of muscle.

An important feature of the femoral shaft is its anterior bow.

The medial cortex is under compression, whereas the lateral cortex is under tension.

The isthmus of the femur is the region with the smallest intramedullary (IM) diameter. The diameter of the isthmus affects the size of the IM nail that can be inserted into the femoral shaft.

The femoral shaft is subjected to major muscular deforming forces (Fig. 32.1).

• Abductors (gluteus medius and minimus): They insert on the greater trochanter and abduct the proximal femur following subtrochanteric and proximal shaft fractures.

• Iliopsoas: It flexes and externally rotates the proximal fragment by its attachment to the lesser

  trochanter.

• Adductors: They span most shaft fractures and exert a strong axial and varus load to the bone by traction on the distal fragment.

• Gastrocnemius: It acts on distal shaft fractures and supracondylar fractures by flexing the distal

  fragment.

• Fascia lata: It acts as a tension band by resisting the medial angulating forces of the adductors.

   

   

   

The thigh musculature is divided into three distinct fascial compartments (Fig. 32.2):

1. Anterior compartment: This is composed of the quadriceps femoris, iliopsoas, sartorius, and pectineus, as well as the femoral artery, vein, and nerve, and the lateral femoral cutaneous nerve.

2. Medial compartment: This contains the gracilis, adductor longus, brevis, magnus, and obturator externus muscles along with the obturator artery, vein, and nerve, and the profunda femoris artery.

3. Posterior compartment: This includes the biceps femoris, semitendinosus, and semimembranosus, a portion of the adductor magnus muscle, branches of the profunda femoris artery, the sciatic nerve, and the posterior femoral cutaneous nerve.

Because of the large volume of the three fascial compartments of the thigh, compartment syndromes

are much less common than in the lower leg.

• The vascular supply to the femoral shaft is derived mainly from the profunda femoral artery. The one to two nutrient vessels usually enter the bone proximally and posteriorly along the linea aspera. This artery then arborizes proximally and distally to provide the endosteal circulation to the shaft. The periosteal vessels also enter the bone along the linea aspera and supply blood to the outer one-third of the cortex. The endosteal vessels supply the inner two-thirds of the cortex.

• Following most femoral shaft fractures, the endosteal blood supply is disrupted, and the periosteal vessels proliferate to act as the primary source of blood for healing. The medullary supply is eventually restored late in the healing process.

• Reaming may further obliterate the endosteal circulation, but it returns fairly rapidly, in 3 to 4 weeks.

Femoral shaft fractures heal readily if the blood supply is not excessively compromised.

Therefore, it is important to avoid excessive periosteal stripping, especially posteriorly, where the arteries enter the bone at the linea aspera.

MECHANISM OF INJURY

Femoral shaft fractures in adults are almost always the result of high-energy trauma. These fractures result from motor vehicle accidents, gunshot injuries, or falls from a height.

Pathologic fractures, especially in the elderly, commonly occur at the relatively weak metaphyseal–diaphyseal junction. Any fracture that is inconsistent with the degree of trauma should arouse suspicion for pathologic fracture.

Stress fractures occur mainly in military recruits or runners. Most patients report a recent increase in training intensity just before the onset of thigh pain.

Recently, insufficiency fractures of the femur have been reported with extended use of bisphosphonates. These fractures have an “atypical” appearance on radiographs including lateral cortical thickening, a medial spike, and a transverse to short oblique fracture line.

CLINICAL EVALUATION

Because these fractures tend to be the result of high-energy trauma, a full trauma survey is indicated.

The diagnosis of femoral shaft fracture is usually obvious, with the patient presenting nonambulatory with pain, variable gross deformity, swelling, and shortening of the affected extremity.

A careful neurovascular examination is essential, although neurovascular injury is uncommonly associated with femoral shaft fractures.

Thorough examination of the ipsilateral hip and knee should be performed, including systematic inspection and palpation. Range-of-motion or ligamentous testing is often not feasible in the setting of a femoral shaft fracture and may result in displacement. Knee ligament injuries are common, however, and need to be assessed after fracture fixation.

More than 1 L of blood may be lost into the thigh. Therefore, a careful preoperative assessment of

hemodynamic stability is essential, regardless of the presence or absence of associated injuries.

No- or low-energy mechanisms should alert the examiner to pathologic causes.

ASSOCIATED INJURIES

Associated injuries are common and may be present in up to 5% to 15% of cases, with patients presenting with multisystem trauma, spine, pelvis, and ipsilateral lower extremity injuries.

Ligamentous and meniscal injuries of the ipsilateral knee may be present in 50% of patients with closed femoral shaft fractures.

RADIOGRAPHIC EVALUATION

Anteroposterior (AP) and lateral views of the femur, hip, and knee as well as an AP view of the pelvis should be obtained.

The radiographs should be critically evaluated to determine the fracture pattern, the bone quality, the presence of bone loss, associated comminution, the presence of air in the soft tissues, and the amount of fracture shortening.

One must evaluate the region of the proximal femur for evidence of an associated femoral neck or intertrochanteric fracture.

If a computed tomography scan of the abdomen and/or pelvis is obtained for other reasons, it should be reviewed because it may provide evidence of injury to the ipsilateral acetabulum or femoral neck.

CLASSIFICATION

Descriptive

Open versus closed injury

Location: proximal, middle, or distal one-third

Location: isthmal, infraisthmal, or supracondylar

Pattern: spiral, oblique, or transverse

Comminuted, segmental, or butterfly fragment

Angulation or rotational deformity

Displacement: shortening or translation

Winquist and Hansen (Fig. 32.3)

This is based on fracture comminution.

It was used before routine placement of statically locked IM nails.

Type I: Minimal or no comminution

Type II: Cortices of both fragments at least 50% intact

Type III: 50% to 100% cortical comminution

Type IV: Circumferential comminution with no cortical contact

Orthopaedic Trauma Association Classification of Femoral Shaft Fractures See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

TREATMENT

Nonoperative

Skeletal Traction

Currently, closed management as definitive treatment for femoral shaft fractures is largely limited to adult patients with such significant medical comorbidities that operative management is contraindicated.

The goal of skeletal traction is to restore femoral length, limit rotational and angular deformities, reduce painful spasms, and minimize blood loss into the thigh.

Skeletal traction is usually used as a temporizing measure before surgery to stabilize the fracture and prevent fracture shortening.

A general rule of thumb is to apply 1/9 or 15% of the patient’s body weight (usually 20 to 40 lb) of traction to the extremity. Fracture length should be assessed via a lateral radiograph.

Distal femoral pins should be placed in an extracapsular location to avoid the possibility of septic arthritis. Proximal tibia pins are typically positioned at the level of the tibial tubercle and are placed in a bicortical location.

Safe pin placement is usually from medial to lateral at the distal femur (directed away from the femoral artery) and from lateral to medial at the proximal tibia (directed away from the peroneal nerve).

Problems with use of skeletal traction for definitive fracture treatment include knee stiffness, limb shortening, heterotopic ossification of the quadriceps, prolonged hospitalization, respiratory and skin ailments, and malunion.

Operative

Operative stabilization is the standard of care for most femoral shaft fractures.

Surgical stabilization should occur within 24 hours, if possible.

Early stabilization of long bone injuries appears to be particularly important in the multiply injured patient.

Stabilization should follow resuscitation efforts.

Intramedu lary Nailing

This is the standard of care for femoral shaft fractures.

Benefits of IM nailing over plate fixation include less extensive exposure and dissection, lower infection rate, and less quadriceps scarring. Additionally, the IM location of the IM nailing results in lower tensile and shear stresses on the implant than with plate fixation.

Closed IM nailing in closed fractures has the advantage of maintaining both the fracture hematoma and the attached periosteum. If reaming is performed, these elements may provide a combination of osteoinductive and osteoconductive materials to the site of the fracture.

Other advantages include early functional use of the extremity, restoration of length and alignment with comminuted fractures, rapid and high union (>95%), and low refracture rates.

Antegrade Inserted Intramedullary Nailing

Surgery can be performed on a fracture table or on a radiolucent table with or without skeletal traction.

The patient can be positioned supine or lateral. Supine positioning allows unencumbered access to the entire patient. Lateral positioning facilitates identification of the piriformis starting point but may be contraindicated in the presence of pulmonary compromise.

One can use either a piriformis fossa or greater trochanteric starting point. The advantage of a piriformis starting point is that it is in line with the medullary canal of the femur. However, it is easier to locate the greater trochanteric starting point. Use of a greater trochanteric starting point requires use of a nail with a valgus proximal bow to negotiate the off starting point axis.

With the currently available nails, the placement of large diameter is no longer necessary. At this point in time, most studies support reaming prior to nail placement.

The role of unreamed IM nailing for the treatment of femoral shaft fractures remains unclear. The potentially negative effects of reaming for insertion of IM nails include elevated IM pressures, elevated pulmonary artery pressures, increased fat embolism, and increased pulmonary dysfunction. The potential advantages of reaming rate include increased periosteal blood flow, the ability to place a larger diameter implant with increased union rates, and decreased hardware failure. At this point in time, most studies support reaming prior to nail placement.

All IM nails should be statically locked to maintain femoral length and control rotation. The number of distal interlocking screws necessary to maintain the proper length, alignment, and rotation of the implant bone construct depends on numerous factors including fracture comminution, fracture location, implant size, patient size, bone quality, and patient activity.

Retrograde Inserted Intramedullary Nailing

The major advantage with a retrograde entry portal is the ease in properly identifying the starting point.

Relative indications include:

• Ipsilateral injuries such as femoral neck, pertrochanteric, acetabular, patellar, or tibial shaft fractures

• Bilateral femoral shaft fractures

• Morbidly obese patient

• Pregnant woman

• Periprosthetic fracture above a total knee arthroplasty

• Ipsilateral through knee amputation in a patient with an associated femoral shaft fracture

Contraindications include:

• Restricted knee motion <60 degrees

• Patella baja

  External Fixation

Its use as definitive treatment for femoral shaft fractures has limited indications.

Its use is most often provisional (damage control) (Fig. 32.4).

Advantages include the following:

• The procedure is fast. A temporary external fixator can be applied in less than 30 minutes.

• The vascular supply to the femur is minimally damaged during application.

• No additional foreign material is introduced in the region of the fracture.

• It allows access to the medullary canal and the surrounding tissues in open fractures with significant contamination.

• Allows for transfer of patients to and from the intensive care unit for testing while maintaining

  skeletal stabilization.

• It takes up to 2 weeks to convert to IM fixation.

Disadvantages: Most are related to the use of this technique as a definitive treatment and include:

• Pin tract infection

• Loss of knee motion

• Angular malunion and femoral shortening

• Limited ability to adequately stabilize the femoral shaft

• Potential infection risk associated with conversion to an IM nail

Indications for use of external fixation include:

• Use as a temporary bridge to IM nailing in the severely injured patient

• Ipsilateral arterial injury that requires repair

• Patients with severe soft tissue contamination in whom a second debridement would be limited by other devices

  Plate Fixation

  Plate fixation for femoral shaft stabilization has decreased with the use of IM nails.

Advantages to plating include:

• It has the ability to obtain an anatomic reduction in appropriate fracture patterns.

• There is a lack of additional trauma to remote locations such as the femoral neck, the acetabulum, and the distal femur.

• Newer implants allow for minimally invasive insertion techniques.

Disadvantages compared with IM nailing include:

• There is a need for an extensive surgical approach with its associated blood loss, risk of infection, and soft tissue insult. This can result in quadriceps scarring and its effects on knee motion and quadriceps strength.

• There is decreased vascularization beneath the plate and the stress shielding of the bone spanned by the plate.

• The plate is a load-bearing implant; therefore, a higher rate of implant failure potentially exists.

Indications include:

• Extremely narrow medullary canal where IM nailing is impossible or difficult

• Fractures that occur adjacent to or through a previous malunion

• Obliteration of the medullary canal due to infection or previously closed management

• Fractures that have associated proximal or distal extension into the pertrochanteric or condylar regions

• In patients with an associated vascular injury, the exposure for the vascular repair frequently

  involves a wide exposure of the medial femur. If rapid femoral stabilization is desired, a plate can be applied quickly through the medial open exposure.

An open or a submuscular technique may be applicable.

As the fracture comminution increases, so should the plate length such that at least four to five

screw holes of plate length are present on each side of the fracture.

The routine use of cancellous bone grafting in plated femoral shaft fractures is questionable if indirect reduction techniques are used.

Femur Fracture in a Multiply Injured Patient

The impact of femoral nailing and reaming is controversial in the polytrauma patient.

In a specific subpopulation of patients with multiple injuries, early IM nailing is associated with elevation of certain proinflammatory markers.

It has been recommended that early external fixation of long bone fractures followed by delayed IM nailing may minimize the additional surgical impact in patients at high risk for developing complications (i.e., patients in extremis or underresuscitated) (Fig. 32.5).

Ipsilateral Fractures of the Proximal or Distal Femur

Concomitant femoral neck fractures occur in 3% to 5% of patients with femoral shaft fractures. Options for operative fixation include antegrade IM nailing with multiple screw fixation of the femoral neck, retrograde femoral nailing with multiple screw fixation of the femoral neck, and compression plating with screw fixation of the femoral neck. The sequence of surgical stabilization is controversial.

Ipsilateral fractures of the distal femur may exist as a distal extension of the shaft fracture or as a distinct fracture. Options for fixation include fixation of both fractures with a single plate, fixation of the shaft and distal femoral fractures with separate plates, IM nailing of the shaft fracture with plate fixation of the distal femoral fracture, or interlocked IM nailing spanning both fractures (high supracondylar fractures).

Open Femoral Shaft Fractures

These are typically the result of high-energy trauma. They are automatically type III injuries due to soft tissue stripping.

Patients frequently have multiple other orthopaedic injuries and involvement of several organ systems.

Treatment is urgent debridement with skeletal stabilization as patient condition allows.

Stabilization can usually involve placement of a reamed IM nail.

REHABILITATION

Early patient mobilization out of bed is recommended.

Early range of knee motion is indicated.

Weight bearing on the extremity is guided by a number of factors including the patient’s associated injuries, soft tissue status, type of implant, and the location of the fracture.

COMPLICATIONS

Nerve injury: This is uncommon because the femoral and sciatic nerves are encased in muscle throughout the length of the thigh. Most injuries occur as a result of traction or compression during surgery.

Vascular injury: This may result from tethering of the femoral artery at the adductor hiatus.

Compartment syndrome: This occurs only with significant bleeding. It presents as pain out of proportion, tense thigh swelling, numbness or paresthesias to medial thigh (saphenous nerve distribution), or painful passive quadriceps stretch.

Infection (<1% incidence in closed fractures): The risk is greater with open versus closed IM nailing. Types I, II, and IIIA open fractures carry a low risk of infection with IM nailing, whereas fractures with gross contamination, exposed bone, and extensive soft tissue injury (types IIIB and IIIC) have a higher risk of infection regardless of treatment method.

Refracture: Patients are vulnerable during early callus formation and after hardware removal. It is usually associated with plate or external fixation.

Nonunion and delayed union: This is unusual. Delayed union is defined as healing taking longer than 6 months, usually related to insufficient blood supply (i.e., excessive periosteal stripping), uncontrolled repetitive stresses, infection, and heavy smoking. Nonunion is diagnosed once the fracture has no further potential to unite.

Malunion: This is usually varus, internal rotation, and/or shortening owing to muscular deforming forces or surgical technique leading to malalignment.

Fixation device failure: This results from nonunion or “cycling” of device, especially with plate fixation.

Heterotopic ossification may occur proximally at the site of nail insertion or within the quadriceps.