The femur is flat on the anterior and lateral surfaces. On the posterior femur surface, there is a taper that is confluent with the linea aspera.

The linea aspera is a very thick fascial structure and frequently remains in continuity but separates from the femur.

Entrapment of the linea aspera between the fracture ends may impede closed fracture reduction, especially with simple fracture patterns. The bone ends may need to be “unwound” to effect a reduction.

The linea aspera protects many perforating periosteal vessels and may help explain the high healing rate of femoral shaft fractures (about 95%).

Thigh compartment syndrome may occur and generally involves the anterior compartment. Frequently, release of the anterior compartment will relieve pressure.

The proximity of the gluteal compartment places it at risk as well. It should also be considered with compartment syndromes.

Both anterior and lateral bowing is important to recognize, especially if abnormal (eg, metabolic bone disease).

The anterior bow has an average radius of curvature of about 120 cm.

If there is excessive bowing, good preoperative planning is needed.

Surgical options for such abnormal bowing include plate fixation or a controlled osteotomy to allow nail placement.²²

Normal aging and osteoporosis results in a biomechanical adaptation of enlarged inner diameter. Thus, elderly individuals may have a larger diameter femoral shaft with a thinner cortex. As in other cylindrical tubes, the bending rigidity of the femur is roughly proportional to the radius to the fourth power.

Normally, periosteal arterial branches supply the outer one-quarter to one-third of the cortex; the direction of blood flow is directed centrifugally from the high-pressure medullary arterial system to the low-pressure periosteal system.²⁷

Once fracture occurs, a reversal of blood flow occurs with blood flowing centripetally from periosteal vessels directed radially inward (because the higher pressure intramedullary system is disrupted).²⁶

For example, a simple transverse fracture with a butterfly fragment is due to a bending force (eg, T-bone vehicle crash).

Spiral fracture patterns are usually due to torsional forces.

The active and passive recoil of the muscle soft tissue envelope will decrease the initial displacement. Thus, the extent of soft tissue injury can be difficult to appreciate.

Open fractures in this setting are usually “inside-out” injuries.

With these injuries, there may be less initial displacement of the fracture and soft tissues, but the amount of soft tissue injury can still be extensive.

In ballistic injuries, the shock and cavitation can result in extensive tissue necrosis.

The mortality of wartime femur fracture before and during World War I (WWI) was approximately 80%. Serendipitous use of a wheeled splint for transport off the battlefield resulted in a precipitous drop in the mortality rate (the Thomas splint was thus developed). During WWI, Hey Groves used metallic rods for the treatment of gunshot wounds but there was a very high infection rate and it was not universally accepted.

Because surgical techniques were primitive in those times, fears about infection and surgical complications resulted in most fractures being treated in traction.

The outcome was frequently a shortened, rotated, varus malunion of the femur. Additional problems such as decubiti, venous thromboembolism, and pulmonary infections with prolonged bed rest resulted in high morbidity and mortality.

Gerhardt Küntscher is considered the father of intramedullary nailing and much of his interest in intramedullary devices originated from his use of the Smith-Petersen nail for femoral neck fractures.

Küntscher’s first nail used (1940) was a V-shaped stainless steel antegrade nail; this V-shaped design had evolved to a cloverleaf design by the late 1940s. Küntscher’s original technique was on open nailing (ie, exposing the fracture site). In Western nations, poor surgical technique resulted in high rates of infection and nonunion.

In the late 1980s, Brumback and colleagues reported the high success rate (98%) of reamed, statically locked intramedullary nails.^{10, 11}

The success rate of femoral nailing using closed technique resulted in low morbidity and began a change in practice to what we perform today.

Early studies outlined the benefits of early reamed femoral nailing.

Later studies identified patients at risk (eg, pulmonary injury, incomplete resuscitation, and brain injury) who benefited from stabilization of life-threatening injuries before fixation.

Although some have advocated plating in such cases, there have been no studies demonstrating the superiority of one method over the other in terms of patient survival.⁶

Metabolic conditions and any musculoskeletal conditions should be elucidated if possible.

These initial splints should be removed and replaced with skeletal or limb traction because of the risk of skin problems in the perineal or ischial and ankle areas. Traction improves patient comfort, restores length, and tightens the surrounding muscles. The taut surrounding musculature decreases potential space for blood loss, provides a tamponade effect to hemorrhage, and serves as a soft tissue stabilizer to the fracture fragments.

The extent of the open wound does not always correlate with the degree of soft tissue or fascial stripping due to the fracture.

It is important to understand that a pulse is a pressure wave and can still be present in the absence of flow; alternatively, the absence of a pulse does not always mean absence of flow. A Doppler ultrasound device should be used in cases where a pulse cannot be palpated.

Hypotension with peripheral vasoconstriction may accompany such injuries.

The limb should be aligned before vascular examination.

Asymmetric or absent pulses warrant a measurement of the ankle-brachial index (ABI). An ABI less than 0.9 is abnormal.

Arteriography should be considered to rule out vascular injury.

The femoral nerve may be difficult to examine secondary to pain associated with the fracture.

Sciatic nerve function can be evaluated for both peroneal and tibial branches.

The peroneal branch is tested with ankle and toe dorsiflexion and sensation on the top of the foot.

Tibial branch function is tested with ankle and toe plantarflexion as well as sensation to the sole of the foot.

Such films can be obtained in the operating room but are essential in planning because the presence of a femoral neck fracture or a fracture about the knee will greatly change the operative tactic.

Attempts should be made to get an internal rotation AP view of the femoral neck. However, with current trauma algorithms, the commonality of the pelvic computed tomography (CT) scan allows imaging of the femoral neck. The scan should be viewed before deciding on the surgical tactic.

CT scanning in these situations may not be sensitive enough to find such fractures.

Use of CT scans of the abdomen that go to the level of the femoral neck have been found to be sensitive enough to identify such occult femoral neck fractures and should be done for most cases.³⁵

The studies by Brumback et al^{7, 8, 9, 10, 11} determined that statically locked nails do not affect healing and avoid the problems of malrotation and shortening. Unreamed nails were proposed to limit effects of canal fill and the theoretical concern of infection. Neither concern was proven, and, in fact, small unreamed nails had the same problems as in the tibia: higher rates of nonunion. Currently, the “ream-to-fit” technique is used.³⁸

Absorbable antibiotic beads (calcium sulfate, not calcium phosphate, mixed with vancomycin or tobramycin) can be used at the time of definitive closure to provide local antibiotic delivery.²⁸

If there is no pin tract infection, conversion from external fixation to intramedullary nailing is best performed within 10 to 14 days after external fixation to minimize infection risk.¹³

In such cases, the risk of infection is increased but acceptable in lieu of prolonged bed rest.

Care should be taken to ensure that the posterior cortex of the proximal fragment is not inadvertently reamed away.

It can result in shortening that may be difficult to overcome without either “unwinding” the fracture or opening the fracture site.

Attention should be paid to adolescents with very valgus neck angles, as some have hypothesized that this can increase the risk of avascular necrosis of the femoral head. However, with newer implants such as trochanteric entry or lateral entry nails, many of these concerns can be alleviated.

Skeletally immature children may still be considered for some form of intramedullary treatment after considering remaining growth, type of fracture, and benefits over other methods of treatment.^{1, 14}