Shaft Femur Fracture

Shaft femur fracture is the fracture of the diaphysis of the femur, an area from the subtrochanteric region to supracondylar region.

The management of these fractures differ greatly from fractures of the other regions and hence are

The femoral shaft Fracture of shaft of the femur or simply called as femur fracture may be categorized into three major groups

• High-energy traumatic fractures
• Low energy traumatic fractures through the pathologic bone (pathological fractures)
• Stress fractures due to repetitive overload.

Traumatic femur fractures in the young individual are generally caused by high-energy injuries. These injuries are often associated with multisystem trauma.

In the elderly, femur fractures may be caused by low energy mechanism such as a fall from standing height.

A preexisting bone disease may cause a  pathological fracture like in the presence of metabolic bone diseases, metastatic disease or primary bone tumors.

The femur is very vascular, and fractures can result in significant blood loss.

Most femur fractures are treated surgically which aims to provide stable, anatomic fixation, and allows mobilization of both hip and knee motion and strengthening.

The incidence of femoral shaft fractures ranges from 9.5 to 18.9 per 100,000 annually.

High-energy injuries are most common in younger males.

Stress fractures are seen in athletes.

Relevant Anatomy

The femur is the strongest, longest, and heaviest bone in the body. The shaft of the femur is a tubular structure with a slight anterior bow and extends from the lesser trochanter to the flare of the femoral condyles. During ambulation, the femur is subjected to many forces like including axial loading, bending, and torsional forces.

Linea aspera is a rough crest of bone running down the middle third of posterior femur. It serves as an attachment site for various muscles and fascia and adds to strength by forming a compressive strut to accommodate anterior bow of the femur.

Muscles in three  compartments of the thigh

• Anterior
  • Sartorius
  • Quadriceps
• Posterior
  • Biceps femoris
  • Semitendinosus
  • Semimembranosus
• Adductor
  • Gracilis
  • Adductor longus
  • Adductor brevis
  • Adductor magnus

[Read more on muscles of hip]

Typically, during weight bearing, the medial cortex is subjected to compressive forces while lateral cortex is subjected to tensile forces.

The blood supply enters the femur through metaphyseal arteries and branches of the profunda femoris artery, penetrating the diaphysis and forming medullary arteries extending proximally and distally.

The femoral artery courses down the medial aspect of the thigh to the adductor hiatus, at which time it becomes the popliteal artery. Injuries to the artery occur at the level of the adductor hiatus, where soft-tissue attachments may cause tethering.

[More anatomical details of femur]

Causes of Femur Fracture

Trauma

• • Motor vehicle trauma
  • Sports injury especially high speed
  • Falls from height
  • Gunshot wounds

Pathologic causes

• • Metabolic bone disease
  • Tumors – Primary or metastatic tumor
  • Infection
  • Prolonged bisphosphonate use

Stress fracture

• • Repetitive impact activities such as running (jogging) and jumping
  • Metabolic bone disease
  • Amenorrheic or oligomenorrheic female runners
  • Abnormal bone mineral density
  • Improper training
  • Improper footwear

Pathophysiology of Shaft Femur Fracture

Femur fracture patterns vary according to the direction of the force applied and the quantity of force absorbed. A perpendicular force results in a transverse fracture pattern, rotational forces may cause spiral or oblique fracture patterns. The amount of comminution present increases with increasing amounts of force.

Pathologic fractures may occur with relatively little force.  These may be the result of bone weakness from osteoporosis or lytic lesions.

Stress fractures of femoral shaft occur from cyclic overloading of the bone. With prolonged repetitive activity, muscles fatigue and an increased force act on bone.

The area most susceptible to stress fractures of the femoral shaft is the medial junction of the proximal and middle third of the femur.

Large muscles attach to the femur can affect the displacement of femur fracture patterns.

[For example, the gluteus medius and minimus attached to the greater cause an abduction deformity to the proximal fragment of the proximal femoral shaft.

The iliopsoas attached to the lesser trochanter results in a flexion deformity.]

Large adductor muscle mass attaches medially, resulting in an apex lateral deformity, especially in distal fractures. The medial and lateral heads of the gastrocnemius cause an extension of distal fragments.

A number of studies have shown an association between atypical femoral shaft fractures and the extended use of bisphosphonates for osteoporosis.

Classification of Femoral Shaft Fractures

Winquist and Hansen

Type 0

• No comminution

Type I

• An insignificant amount of comminution

Type II

• Greater than 50% cortical contact

Type III

• Less than 50% cortical contact

Type IV

• Segmental fracture with no contact between the proximal and distal fragment

Clinical Presentation of Femoral Shaft Fractures

In trauma, history usually is obvious. Significant pain and deformity are reported in the thigh. Stress fractures or fractures occurring with minimal trauma require history in greater detail.

Prodromal pain prior to a traumatic event is suggestive of a pathological or overuse origin.

Patients should be questioned as to aggravating and alleviating factors.

For femoral stress fractures in sportspersons, a detailed training and competition history should be obtained. A sudden increase in mileage, intensity, or frequency of training, a change in terrain or running surface should be enquired.

Symptoms of stress fractures are aggravated by activity and relieved by rest.

Pain from femoral shaft stress fracture is most frequently located in the anterior thigh.

Female runners may have an abnormal menstrual history and a history of disordered eating.

On examination, the thigh is often swollen secondary to hematoma formation.

In the case of trauma, associated injuries must be addressed. A head-to-toe examination including the pelvis, spine, other bones, nerves and vessels of the affected extremity should be examined.

Tenderness on examination and visible deformity typically are noted.

The extremity may appear shortened, and crepitus may be noted with movement.

Look for vascular and neural deficits. If the present should be investigated further.

Significant blood may result in tachycardia and hypotension. Fractures are commonly associated with other bony injuries, including tibial shaft fractures, ipsilateral femoral neck fractures, and extension of the fracture into the distal femur.

In the delayed presentation, look for compartment syndrome. Pain out of proportion to the injury could suggest an acute compartment syndrome and/or muscle ischemia due to arterial injury.

In case of stress fracture which is not complete yet, the examination may show

• Subtle tenderness and/or swelling.
• Muscle bulk and tone is typically normal.
• Pain with forced rotation or axial loading or bending stress
• Antalgic gait with limp
• Hop Test
  •  Single leg hop will reproduce symptoms on the affected side.
• Fulcrum Test
  • Patient seated
  • Examiner applies gentle downward pressure on the knee
  • Another arm of the examiner is used as a fulcrum to produce an anterior force vector on the posterior thigh.
  • May reproduce the patient’s symptoms.

Lab Studies

No specific laboratory studies are indicated for the femur fracture. Studies for anemia may be done in acute blood loss.

The patient may be investigated for stress fractures and pathological fractures. The common tests include

• • Complete blood cell (CBC) count
  • BioChemistry panel
  • Prothrombin time (PT) / activated partial prothrombin time (aPTT)
  • Urinalysis
  • ESR/CRP
  • Oncological markers in metastatic disease
  • Metabolic bone work-up including vitamin D and calcium levels

For patients who require surgery, preoperative tests, including chest radiography and ECG are done.

Imaging Studies

X-rays

In case of trauma following x-rays should be done

• Anteroposterior radiograph of the pelvis
• AP and lateral radiograph of the entire femur, hip, and knee

• Chest and spine x-rays of the chest to rule out injury

In pathological and stress fractures, radiographs of the contralateral limb may be done for comparison.

Following images show various configurations of fracture of shaft of the femur

CT/ MRI

In polytrauma, CT of the head, neck, and abdomen if indicated is done. CT of the pelvis is considered in high energy injury femur fractures to rule out femoral neck fracture.

CT/MRI is also done in cases of tumors or infections.  In the case of malignancy, CT chest is done to look for metastases from a primary bone tumor

MRI can reveal bone marrow signal earlier in the stress-reaction process than standard radiographs and radionuclide scanning.

Positron emission tomography-computed tomography (PET-CT) can be used to assess for other areas of involvement in the tumor.

Radionucleotide scanning

• A bone scan is a standard for the diagnosis of stress fractures
• More sensitive than and plain radiographs.

Bone mineral density evaluation

To rule out osteoporosis or osteopenia.

If a vascular injury is suspected, perform arteriography

Diagnostic Considerations

Associated extremity fractures should be considered. Common associated injuries are

• Ipsilateral femoral neck fracture
• Ipsilateral knee injury
• Spine fractures
• Pelvic fractures

Pathological and stress fractures should be evaluated to find out the cause

Differential Diagnoses

• Chronic Exertional Compartment Syndrome
• Hematoma
• Hip Dislocation
• Muscle contusion
• Muscle strain

Approach to Treatment of Femur Fracture

Acute Care

More severe and life-threatening injuries are addressed first. For femur fracture, splint the extremity in. Hare or Thomas traction splints are most commonly used for immobilization. The first priority in treatment is to rule out other life-threatening injuries and stabilize the patient.

If the fracture is open, it needs to be dressed/irrigated.

Drugs for pain control are administered. Opioids or NSAIDs may be given.

With open fractures, administer tetanus toxoid if needed and use antibiotics.

Before definitive operative management of a femur fracture, the patient should be hemodynamically stable and fully resuscitated.

Elderly patients require evaluation by for management of any acute or chronic medical conditions

Definitive Treatment

Traumatic Fractures

Nonoperative treatment consists of a long leg cast and is indicated in nondisplaced femoral shaft fractures in patients with multiple medical conditions.

Intramedullary nailing is the treatment of choice for the majority of femoral shaft fractures occurring in adults. Nailing can be performed in an antegrade or retrograde fashion. Other treatment options include plate and screw fixation as well as external fixation

In cases of pathologic fracture, treatment is dictated by not only location but also lesion type. In primary bone tumors, the goal of surgical treatment is curative whereas in metastatic tumors the goal is palliative.

Physical therapy is started following stable fixation of the fracture to improve hip and knee range of motion. Muscle strengthening and gait training are recommended. Weight-bearing status is dependent upon fracture pattern and surgical intervention.

Stress Fractures

• For non-displaced femoral shaft stress fractures, protected crutch-assisted weight bearing is implemented for a minimum of 1-4 weeks
• Progression to full weight bearing can gradually commence once pain has resolved.
• Patients must avoid running for 8-16 weeks while the low-impact training program/phase is completed.
• Patients must maintain upper extremity and cardiovascular fitness and avoid lower extremity exercise early in the healing process.
• Surgery for cases recalcitrant conservative treatment. Intramedullary nailing, whether antegrade or retrograde, is the treatment of choice for these cases.

Surgical Treatment of Femur Fractures

Most of the discussion applies to traumatic displaced fractures of the shaft of the femur.

Timing of Surgery

The decision as to when to operate must be based on a number of factors.  Early stabilization is warranted.

If surgery is to be delayed, the fracture must be properly splinted and the extremity placed in skeletal traction with the fragments in the best possible alignment.

Multiple System Injuries

The early stabilization of the femoral shaft prevents or reverses progressive respiratory failure, multiple organ failure, infection,  and fat embolism.

It also reduces the incidence of fracture-related complications and improves functional outcomes.

The femur may be operated once their condition stabilizes.

Head Injury

An unconscious patient whose cerebral status is stable and who does not have an enlarging intracranial mass with rising intracranial pressure should be operated early.

Open Fractures

The debridement of an open wound should be carried out on an emergency basis. An open fracture must be stabilized at the time of surgical debridement, by internal fixation or external fixator.

Vascular Injury

Vascular injury demands immediate intervention to safeguard the survival of the extremity. The fracture can be fixed with external fixator at the time of arterial exploration/surgery.

Ipsilateral Neck Fracture or Dislocation  of the Hip

Both injuries, but particularly the latter, create an emergency situation requiring urgent fixation of both the injuries.

Ipsilateral  Ligamentous Disruption of the Knee

Internal fixation of the fracture should be done at the earliest and then reconstruction of the disrupted ligaments should be done as the condition permits, preferably immediately.

Floating Knee Syndrome

Patients who sustain fractures of the ipsilateral femur and tibia have the so-called floating knee syndrome. They are treated as soon as the general condition of the patient allows.

Types of Surgery

Antegrade Intramedullary Nailing

Antegrade intramedullary nailing is the gold standard for treatment of shaft femur fractures. As noted before, stabilization within 24 hours is associated with, decreased pulmonary complications,  decreased thromboembolic events and better functional outcomes.

It may sometime be preceded by a provisional fixation by external fixator for few days in selected cases [i.e. open fractures]

The nail is inserted through piriformis fossa proximally. In patients where entry point localization is difficult, a trochanteric entry point could be made.

Most commonly, the reamed nailing is used and studies have shown it to be better than unreamed nailing as reaming results in better contact with bone and thus better union.

Unreamed nailing can be considered for a patient with bilateral pulmonary injuries.

The nail should be locked on both proximal and distal aspects by using interlocking screws. Interlocking offers stability and rotational control.

Post-operatively, the patient is allowed weight bearing as tolerated and physical therapy is initiated.

Retrograde intramedullary nailing

It is indicated in

• An ipsilateral femoral neck fracture
• Floating knee (ipsilateral tibial shaft fracture)
• Ipsilateral acetabular fracture
• Bilateral femur fractures
• Morbid obesity
• Blocked medullary canal by a proximal implant from previous surgery
• Pregnant woman – The lower abdomen can be fully shielded, and the fetus will not be exposed to any radiation.

The nail is inserted from the lower end of the femur. It can be done in the supine position and avoids repositioning. With ipsilateral fracture tibia, the same incision can be used for tibial fixation. With an acetabular fracture, it does not compromise acetabular exposure.

An example of retrograde nailing is given below

The results are comparable to antegrade femoral nails.

The incision is given, starting at distal pole of the patella and moving proximally, 2- cm in length. The bone is approached by a medial parapatellar or transtendinous approach. Postoperative care is similar to antegrade nailing.

Though the results are similar to antegrade nailing, knee pain, screw irritation are more frequently encountered. Ligament or cartilage injury can occur.

External fixation

It is often a temporary measure and conversion to intramedullary nail is done within 2-3 weeks. Therefore, pins are placed so that they do not compromise the nail path. Two pins should be used on each side of the fracture line.

It is indicated in unstable polytrauma victim, open fractures, arterial repairs. Pin tract infection and knee stiffness are common problems.

Open Reduction and Plate Fixation

This is indicated in

• Ipsilateral neck fracture requiring screw fixation
• Fracture at the distal metaphyseal-diaphyseal junction
• Inability to access medullary canal

Plating is inferior when compared to IM nailing and is done when nailing cannot be done. It is associated with increased rates of    infection, nonunion and hardware failure

Ipsilateral Femoral Neck fracture and Fracture Shaft of Femur

In this situation, femoral neck fracture takes priority because the anatomic reduction is necessary to avoid complications of AVN and nonunion.

Methods which can be used are

• Screws for the neck with a retrograde nail for shaft
• Screws for neck and plate for shaft
• Compression hip screw for the neck with a retrograde nail for shaft

Complications of Femur Fracture and Treatment

Heterotopic ossification

It could be as high as 25% but often is not significant clinically.

Pudendal nerve injury

It is often caused by traction on a fracture table. Could be 10% in such cases.

Femoral artery or nerve injury

It is a rare injury which might occur when inserting proximal interlocking screws during a retrograde nail

Malunion

With modern surgical treatment, the most common malunion is rotational malalignment because angulation and shortening are taken care of.  It is more common in proximal fractures than distal.

Use of a fracture table increases the risk of internal rotation deformities when compared to manual traction. Malalignment is more common with fracture comminution.

Mild malrotation can be compensated by hip rotation. Severe ones need osteotomy.

Delayed Union and Nonunion

The delayed union can be tackled by dynamization of nail with or without bone grafting.

Nonunion is seen in about 10% of cases. Smoking and postoperative use of NSAIDs are known risk factors.

Nonunions are addressed by reamed antegrade exchange nailing which involves removal of the nail, reaming and putting a nail of bigger size along with bone grafting.

Infection

It is not common and seen in < 1% of cases. Superficial infections are dealt with by antibiotics, repeat dressings, wound irrigation and debridement.

Severe infections require removal of the hardware and if the fracture has not united, application of external fixator.