Chapter 273: Hip and Femur Injuries

Injuries to the hip and femur are common, occurring most often in the elderly population secondary to falls. Hip fractures are a significant and costly public health concern. Age, race, and gender are important risk factors for hip injuries; the incidence is more than two times greater in women than in men.¹

Morbidity and mortality from hip and femur fractures are due to complications from prolonged immobilization, with venous thromboembolism being the most common complication. Patients with hip fracture have a five- to almost eightfold increased risk of all-cause mortality in the first 3 months after the injury, and increased mortality persists for years afterward. Another significant portion of patients will have markedly decreased functional capacity. Advanced age, male gender, and comorbidities all increase mortality risk following hip fracture.²

This chapter discusses the diagnosis and ED management of fractures of the hip and proximal femur, fractures of the femoral shaft, and anterior and posterior hip dislocations. Fractures involving the femoral condyles are discussed in chapter 274, Knee Injuries.

For purposes of this chapter, we define the hip as the anatomic region including the head and neck of the femur to 5 cm distal to the lesser trochanter. The femoral shaft is the portion of the femur distal to the lesser trochanter, down to but not including the femoral condyles.

The hip is a ball-and-socket joint formed by the femoral head and the acetabulum. The fibrous capsule that surrounds the joint on all sides is quite strong, attaching proximally at the acetabulum and distally on the intertrochanteric line on the anterior surface. The joint capsule is weakest posteriorly where it attaches to the femoral neck. The femoral head and shaft are connected at the obliquely angled femoral neck. Blood is supplied to the femoral head mainly from the medial and lateral femoral circumflex arteries that form an extracapsular ring with branching retinacular arteries in the joint capsule. Therefore, intracapsular fractures can compromise blood supply to the femoral head. Less important blood supply includes branches of the obturator and gluteal arteries, with a small contribution from the foveal artery at the ligamentum teres.

Hip fractures are classified as intracapsular (femoral head and neck) or extracapsular (trochanteric, intertrochanteric, and subtrochanteric). See Figures 273-1 and 273-2 and Table 273-1. The prognosis for successful union and restoration of normal function varies considerably with the fracture type. Most fractures occur in older patients with osteoporosis or other bony pathology secondary to systemic disease. Younger patients are more likely to have femoral shaft fractures or hip dislocation secondary to high-energy trauma.

In intracapsular fractures with displacement, blood supply to the femoral head may be compromised due to direct injury to the blood vessels, tension from the fracture, or compression secondary to a hemarthrosis. Urgent reduction of the fracture may restore blood flow, although avascular necrosis occurs in 15% to 35% of patients unless some of the capsular vessels remain intact.³ Extracapsular fractures less commonly cause vascular compromise.

HISTORY

History of a recent fall or motor vehicle crash suggests the possibility of hip fracture and other injuries. Falls should also prompt questioning about possible syncope, especially in the ill or elderly. Understanding the mechanism of injury can identify associated fractures, such as fractures of the pelvis or about the knee. Important historical factors, such as cancer, chronic kidney disease, or prolonged steroid use, increase the risk of osteoporosis, avascular necrosis, and pathologic fractures.

Patients with hip fracture or dislocation will typically have pain at the site of the injury, but may also report knee pain, groin pain, or pain at sites of other injuries. Determine the duration of immobilization to assess for dehydration, venous thrombosis, or rhabdomyolysis.

PHYSICAL EXAMINATION

After the primary survey and stabilization, carefully examine the patient for deformities, shortening, rotation, lacerations, bruising, or instability of the limbs or tenderness of the pelvis or sacrum. Note any focal tenderness or crepitance. If no significant abnormalities are found, evaluate range of motion of the hips. If rotation of the hip with the leg in extension is painful, avoid other hip maneuvers. Identification of a hip or pelvic injury in a trauma victim should raise suspicion for concomitant intra-abdominal, retroperitoneal, femoral shaft, knee, or urologic injuries. Perform a rectal exam if concern exists for concurrent spinal or pelvic injuries, including evaluation of the prostate in males.

Injuries to the hip and femur should also raise concern for damage to adjacent nerves and vasculature, especially the femoral and sciatic nerves and femoral blood vessels. Assess motor and sensory function of these nerves and their major branches (Table 273-2). Evaluate pulses distal to the site of injury, including popliteal, dorsalis pedis, and posterior tibialis pulses. If concern exists for vascular injury, further testing should be performed and may include ankle-brachial indices, angiography, or duplex US.

IMAGING

Consider radiographic evaluation of the pelvis and hips in all unconscious patients who have sustained multiple injuries or have a concerning mechanism for pelvic, hip, or lower extremity injury.

Include anteroposterior and lateral views of the hip in the initial radiographic evaluation. An anteroposterior pelvis view is also useful as it allows comparison of both sides. Conventional radiographs are estimated to be 90% to 98% sensitive for hip fractures.⁴ Other views may be requested by consulting orthopedists; in certain instances, additional views (e.g., Judet view) may allow better identification and detail of the acetabulum or femoral head and neck. Imaging of the femoral shaft or knee may also be necessary, following the adage to assess the joint above and the joint below the injury.

Pain with weight bearing in the face of normal radiographs should raise suspicion for occult fracture, especially at the femoral neck or acetabulum.⁵ MRI is highly sensitive (nearly 100%) for occult fractures and is also useful in identifying other injuries that may explain the patient's symptoms. CT may be useful in identifying nondisplaced fractures not easily seen on conventional radiographs but is not as sensitive or accurate as MRI for occult fracture. Although bone scanning is sensitive for detecting occult fracture, neoplasm, and avascular necrosis, MRI has largely replaced it.^4,5,6,7

FEMORAL HEAD FRACTURES

Isolated femoral head fractures are uncommon and are typically associated with dislocations of the hip (Table 273-1). The signs and symptoms are often from the dislocation rather than from the fracture itself. They are usually best seen on radiographs obtained after reduction of a hip dislocation.

The standard anteroposterior and lateral views usually demonstrate the fragment adequately. Judet views or thin-cut CT scans are often recommended for further evaluation of the acetabulum and fracture fragmentation.

Treatment is to reduce the associated dislocation and then attain anatomic reduction of the fracture fragment (Table 273-3). See subsequent section on dislocations for further discussion. Management of concomitant life-threatening injuries due to high-energy trauma must take priority.

Prognosis is related to the severity of the initial trauma resulting in the dislocation and associated injuries, delay to reduction, and repetitive unsuccessful reduction attempts.⁸

FEMORAL NECK FRACTURES

Femoral neck fractures are most commonly seen among older adults with osteoporosis and occur more frequently in women than in men. Falls are the most common cause (90%), but stress or traumatic femoral neck fractures may be seen in younger patients (Table 273-1).⁹ There are multiple classification systems for femoral neck fractures, but it is most useful to describe them as displaced or nondisplaced. Femoral neck fractures are intracapsular, and blood supply to the femoral head may be disrupted.

The symptoms seen with femoral neck fractures range from complaints of mild pain in the groin or inner thigh in patients with an incomplete fracture, to moderate to severe pain in patients with displaced fractures. Patients with nondisplaced fractures may be somewhat ambulatory, whereas those with displaced fractures are typically unable to bear weight at all. Examination findings can be subtle in nondisplaced fractures, while displaced fractures are quite evident with the leg held in external rotation, abduction, and shortened (Figure 273-3).

Radiographic evaluation is essential in any patient suspected of having a femoral neck fracture. Ideally, the standard anteroposterior view should have the patient internally rotated as much as patient condition allows to best demonstrate the femoral neck. Nondisplaced fractures may be subtle. The anteroposterior view should be inspected for a fracture line starting on the superior surface of the neck (Figure 273-4). Disruption of Shenton's line, a smooth curvilinear line along the superior border of the obturator foramen and the medial aspect of the femoral metaphysis, may be appreciated on the anteroposterior view in some instances (Figure 273-5). Evaluate the neck-shaft angle in suspected fractures; normal is 120 to 130 degrees (Figure 273-6). The neck-shaft angle is measured at the intersection of lines drawn down the axis of the femoral shaft and the femoral neck.¹⁰ Displaced fractures are obvious on the anteroposterior view, but a lateral view should also be obtained to ascertain the exact fracture position. Approximately 6% to 9% of patients with a femoral neck fracture will have an ipsilateral femoral shaft fracture.¹¹

Treat pain, immobilize the extremity in a position of comfort, and obtain orthopedic consultation in the ED. Skeletal traction is contraindicated for femoral neck fractures because it may further compromise femoral head blood flow.

For both displaced and nondisplaced fractures, outcomes are generally best with surgical fixation because this leads to earlier mobilization and less morbidity and mortality than with conservative management.^12,13 Decisions regarding the timing and type of operative intervention depend on the patient's physiologic age, activity level, and fracture severity.¹⁴ Conservative treatment may be considered in those whose operative risk outweighs potential benefit or in patients who are not ambulatory.

The complications of femoral neck fractures are significant (Table 273-3). Prognosis is related to the number and severity of complications. A higher grade of fracture displacement also implies a worse prognosis for healing and repair.

ISOLATED TROCHANTERIC FRACTURES

Greater trochanteric fractures are usually caused by avulsions at the insertion of the gluteus medius. In the younger population (7 to 17 years of age), this is a true epiphyseal separation, in contrast to the adult population, in whom the cause is direct trauma (Table 273-1).

Lesser trochanteric fractures caused by an avulsion secondary to forceful contraction of the iliopsoas are commonly seen in children and young athletic adults, particularly gymnasts and dancers. Lesser trochanter fractures in older patients with minimal trauma should be considered pathologic until proven otherwise.¹⁵

Standard anteroposterior and lateral views reveal the displacement. CT of the pelvis may be helpful if a fracture is strongly suspected but difficult to visualize.

In most instances, the treatment is crutches with weight bearing as tolerated until orthopedic follow-up is obtained within 3 to 5 days, and then gradually increasing to full activity. Full recovery generally occurs in patients with healthy bone. Operative fixation may be indicated in cases where there is significant displacement of the fracture fragment (Table 273-3).

INTERTROCHANTERIC FRACTURES

Intertrochanteric fractures are defined as extracapsular fractures occurring in a line between the greater and lesser trochanters. They generally occur in the elderly and are more common in women, again due to the high incidence of osteoporosis. The mechanism of injury is usually a fall (Table 273-1).

Patients typically have marked pain and deformity on examination, and fractures are usually easily visualized on standard anteroposterior and lateral views. Intertrochanteric fractures should be classified as sTable or unsTable based on the number of fracture lines and the amount of displacement.¹⁶

After life-threatening injuries have been excluded, the consulting orthopedic physician can then admit the patient to the hospital and perform surgical fixation as soon as possible (Table 273-3). Skin traction is not recommended for either stabilization or pain control.^17,18

The complications and prognosis are related to associated injuries and prior disease. Blood loss into the leg can be significant, and some patients will require crystalloid or blood transfusion.¹⁹ Infection and pulmonary embolism are the main complications. Avascular necrosis and nonunion are uncommon complications.

SUBTROCHANTERIC FRACTURES

Subtrochanteric fractures may be seen in three different populations: older patients with osteoporosis who fall (Table 273-1), younger patients as a result of major trauma, or patients with bony metastases.

The symptoms and signs are similar to those of intertrochanteric or femoral shaft fractures: localized pain, deformity, swelling, and crepitance. Significant blood loss may develop. Evaluate for concomitant life-threatening injuries.

Standard anteroposterior and lateral views of the hip are typically sufficient to evaluate these fractures. Consider radiographic studies of the pelvis, femur, and knee to exclude associated fractures.

ED treatment consists of pain control, immobilization, and orthopedic consultation. Hare^® (Dynamed, Westbury, Tasmania) or Sager^® (Minto Research and Development, Inc., Redding, CA) splints (Figures 2-7 and 2-8, respectively) are commonly employed in the prehospital setting and infrequently in the ED (also see chapter 2, Prehospital Equipment and Adjuncts). Traction splinting may ease pain and provide some fracture reduction.¹⁸ Do not apply a traction splint if there is open fracture, suspected pelvic fracture, hip dislocation, suspicion for neurovascular injury to the extremity, or injury about the knee, as a traction splint may exacerbate neurovascular or knee injury. Operative reduction/internal fixation is generally indicated for complicated fracture management.

OCCULT HIP FRACTURES

Symptoms suggestive of fracture, but with negative plain radiographs, are called occult hip fractures.⁴ Anywhere from 3% to 38% of hip fractures are initially "occult."⁶ Stress, incomplete, or nondisplaced fractures may not become evident on plain radiographs for days or weeks after injury. Pain with axial loading, restricted mobility prior to the injury, and risks for osteoporosis should all raise suspicion for occult fracture.²⁰ MRI is the imaging of choice because it is both sensitive and specific.⁴ If clinical suspicion is high, obtain an MRI in the ED, or if that is not possible, obtain an MRI within the next 24 to 48 hours—with the patient non–weight bearing until diagnosis is confirmed and orthopedic follow-up is obtained.

Fractures of the shaft of the femur most often occur in younger patients secondary to high-energy trauma; associated traumatic injuries are common. Severe, direct trauma may result in transverse fractures (most common) with displacement, oblique or spiral oblique fractures, or comminuted segments. Pathologic fractures are uncommon but can occur secondary to metastases or to primary bone tumors. Femoral shaft fractures are generally evident in the prehospital setting because of the shortening, deformity, and associated swelling. Initial stabilization of the patient should take place in the field along with spinal immobilization. It is generally advised to splint the affected extremity with a traction splint at the time of injury, to minimize pain, prevent further fracture comminution, and minimize blood loss. Hare^® or Sager^® traction splints can be placed over the trousers, applying traction to a sling around the ankle and forefoot. Traction splints are contraindicated in cases of open fracture or in suspected sciatic nerve, knee, or vascular injury. For the latter, splint placement without application of traction is indicated.

Neurovascular examination of the affected extremity is important since sciatic nerve injury, though uncommon, can occur (Table 273-2). The fracture is typically evident on standard anteroposterior and lateral views of the femur. Evaluation, including a thorough exam and imaging, of the joints above and below (pelvis, hips, knees) is generally needed to assess for other orthopedic injuries. Open femur fractures require broad-spectrum antibiotics and copious irrigation. Further irrigation and debridement are accomplished in the operating room. Obtain early orthopedic consultation; most patients require surgical intervention. Blood loss can be significant from the fracture itself or from other injuries.

Intermedullary nailing is the preferred treatment for most femoral shaft fractures. In severely contaminated open fractures, external fixation may be the preferred method of treatment. Patients with severe concomitant injuries may benefit from early external fixation and delayed operative reduction and internal fixation.²¹

Dislocations of native hips typically result from high-energy trauma, and up to 95% of patients have other associated injuries.²² Motor vehicle crash is the most common cause. Posterior dislocations of native hips account for >90% of dislocations; the remaining 10% are anterior and can be classified as superior or inferior.²³ Dislocations of prosthetic hips can occur with minimal trauma. This section discusses the diagnosis and management of posterior and anterior native hip dislocation and the ED management of prosthetic hip dislocation.

Hip dislocations (dislocations of native hips) are orthopedic emergencies and should be reduced as quickly as possible, preferably within 6 hours of the event, in order to reduce the risk of avascular necrosis to the femoral head. Dislocations with neurovascular compromise need reduction as soon as possible. Treatment options include closed reduction of posterior hip dislocations or prosthetic hip dislocations in the ED under procedural sedation, or in the operating room with general anesthesia. Anterior hip dislocations require reduction in the operating room. Open reduction by an orthopedic surgeon is indicated for irreducible fractures, unsatisfactory reductions, and complex fracture dislocations.²³

POSTERIOR HIP DISLOCATION AND REDUCTION MANEUVERS

Posterior hip dislocations (Figure 273-7) are caused by posterior force applied to a flexed knee, most commonly a dashboard injury from high-speed motor vehicle crashes. Acetabular fractures often result; femoral neck, femoral shaft, and knee injuries are often seen as well. On examination, the extremity is shortened, internally rotated, and adducted. Perform a careful neurovascular examination to identify associated sciatic nerve injury or vascular injury (Table 273-2).

Anteroposterior and lateral radiographs of the pelvis and hip identify the posterior dislocation (Figure 273-8), but further assessment of the acetabulum and femur must be performed, either with Judet views or CT, to evaluate for associated fractures. Hip dislocations are difficult to recognize if there is an associated femoral shaft fracture, so routinely obtain radiographs of the pelvis and hips in such cases. Complications of posterior dislocation include sciatic nerve injury in approximately 10% of patients and avascular necrosis of the femoral head that increases in direct proportion to the delay in anatomic reduction.

Multiple techniques exist for closed reduction of posterior hip dislocations (Figures 273-9,273-10,273-11,273-12); it is advisable for the ED physician to be proficient with more than one technique. Nearly all of the techniques involve providing in-line traction while flexing the hip to 90 degrees, and then performing gentle internal-to-external hip rotation.

The Allis maneuver is the most commonly performed technique. In-line traction is performed with simultaneous hip flexion and internal rotation (Figure 273-9). Flex the patient's knee and hip to 90 degrees. An assistant should apply downward pressure to the anterior superior iliac spines. Grasp the knee with both hands. Pull and simultaneously rotate the femur laterally and medially.

With the Bigelow maneuver, the patient should lie supine with the affected hip and knee flexed 90 degrees (Figure 273-10). Secure the patient's knee with your flexed elbow, and grasp the patient's foot with the opposite hand. Have an assistant apply downward pressure to the anterior superior iliac spines. Now, using your flexed elbow, lift upward at the patient's knee to apply traction to the femur. Externally rotate and extend the hip while applying traction to the femur at the patient's knee. Another variation is represented in Figure 273-11.

Another method is the Captain Morgan technique, in which the physician's knee is used as a fulcrum (Figure 273-12).²⁴

After reduction, gently take the hip through range of motion to ensure stability, repeat the neurovascular examination, and obtain postreduction imaging to ensure reduction is satisfactory. The patient may then be placed in an abduction pillow or brace, a hip binder, or a knee immobilizer based on the consulting orthopedist's preference. Most patients will require admission, because this injury is most often due to significant trauma.

If several attempts at reduction are unsuccessful, emergency orthopedic consultation is needed to provide reduction either in the ED or the operating room. Difficulties with reduction may be due to occult fracture or incarcerated tendon or capsule. A postreduction CT is generally recommended to specifically identify associated acetabular or femoral head fractures that were not evident on plain radiographs.²³

ANTERIOR HIP DISLOCATION

In anterior hip dislocations (Figure 273-13 A,B), the femoral head rests anteriorly to the coronal plane of the acetabulum. Anterior dislocations can be superior (pelvic) or inferior (obturator) depending on the degree of hip flexion present at the time of injury. The mechanism of injury is forced abduction that causes the femoral head to be levered out through an anterior capsular tear. The affected extremity is in abduction and external rotation. The clinical appearance of superior versus inferior dislocations is dramatically different (Figure 273-13 C,D). Neurovascular compromise is an unusual complication. However, a thorough exam is warranted to detect injury to the femoral artery or nerve (Table 273-2).

An anteroposterior view of the pelvis can easily demonstrate the femoral head to be anterior to the acetabulum. A lateral view illustrates the anterior dislocation more clearly, although it may be difficult to obtain secondary to patient discomfort. Anterior hip dislocations usually require reduction in the operating room.

DISLOCATIONS OF PROSTHETIC HIPS

Prosthetic hips may dislocate relatively easily from minor trauma or movements that place the hip past 90 degrees of flexion while adducted. Approximately 1% to 10% of prosthetic hips dislocate, the majority in the first few months after surgery.²⁵ Avascular necrosis of the femoral head is not a complication since there is no blood flow to the prosthetic joint capsule. However, sciatic nerve injury or damage to the prosthesis may occur.

Most dislocations of prosthetic hips are posterior and can be reduced using procedural sedation in the ED with the techniques described previously. A review of 410 prosthetic hip dislocations reported that emergency physicians were successful at 79% of reductions in the ED, and orthopedists were successful at 71% of reductions in the ED—with no difference between emergency physicians and orthopedists in the proportion of successfully relocated hips in the ED and no difference in complications. The ED length of stay for ED-reduced prosthetic hip dislocations was about one third shorter than that for orthopedist-reduced dislocations. This study did not describe the types of prostheses reduced.²⁶ There are multiple types of implants, such as modular or constrained implants, which may not be amenable to closed reduction. It is advisable to discuss the treatment plan with the consulting orthopedist prior to attempting any reduction maneuvers.

ATHLETES

Stress fractures of the femoral neck are a recognized cause of hip pain in athletes, especially runners and football players. The onset of pain is often insidious and may mimic other common conditions such as bursitis or muscle strain. Patients often report pain in the groin, medial thigh, or knee. Consider MRI if clinical suspicion is present for stress fracture in a high-risk patient.²⁷ If imaging is not readily available, then the patient should be made non–weight bearing and told to avoid all athletic activities until orthopedic evaluation can be obtained (optimally in the next 48 hours).²⁸

ELDERLY PATIENTS

The majority of hip and femur injuries occur in the elderly. Most will have underlying comorbidities that also require evaluation. For this reason, it is often useful to employ a multidisciplinary approach, which may involve social services to follow up for home safety evaluation as well as early involvement of the patient's primary care physician or a hospitalist.¹² Admit patients with suspected fractures who have poor follow-up, no social support, or suboptimal living conditions. Consider the possibility of elder abuse in elderly patients with falls and fractures. See chapter 295, Abuse of the Elderly and Impaired, for a detailed discussion of elder abuse.

PAIN CONTROL

Nearly all patients with hip or femur injuries will require analgesia. Patients with orthopedic injuries sometimes receive inadequate analgesia in the ED.²⁹ Use parenteral narcotics for pain control unless there is a contraindication. Femoral nerve block should be considered (see chapter 36, Local and Regional Anesthesia, for technique).

INJURY PREVENTION

The use of hip protection pads for the prevention of hip fractures in the elderly have yielded conflicting results, with no definitive reduction in fracture rates demonstrated.³⁰ The increasing use of bisphosphonates for osteoporosis prevention has coincided with the modest reduction in hip fracture incidence in the U.S.; however, there is no evidence for a directly causal relationship as of now. Calcium and vitamin D supplementation may also play a role.¹ The best current recommendations are finding strategies to reduce falls and preventing osteoporosis.