Fractures of the proximal femur are common in elderly individuals, who have decreased bone mass and a higher frequency of falls. Women are more likely than men to sustain femoral neck or intertrochanteric fractures because of their higher incidence of osteoporosis. The vast majority of patients with hip fractures require operative treatment, and the primary care provider’s knowledge of the patient’s medical condition and preinjury functional level is essential in making decisions regarding surgery.
Fractures of the femoral shaft and distal femur are relatively uncommon and are usually the result of significant trauma from automobile accidents in younger patients and falls in elderly people. Pelvic fractures are a leading cause of traumatic morbidity and mortality. The primary care provider involved in trauma care plays an important role in the recognition and stabilization of patients with pelvic fractures.
Femoral Neck Fractures
As the population ages, the number of hip fractures will increase substantially. Current estimates are 500,000 hip fractures at a cost of over $10 billion per year in the United States. Risk factors in the elderly population include falls and altered bone density.
The femoral neck lies within the hip joint capsule, and fractures of the femoral neck are considered intracapsular. The hip capsule, composed of supporting ligaments, arises from the acetabular ring and attaches to the intertrochanteric crest anteriorly and the midportion of the neck posteriorly.
The most significant anatomic feature of the femoral neck is its precarious vascular supply. Circumflex branches of the profunda femoris artery form an extracapsular ring at the base of the neck ( Figure 11-1 ). Ascending branches, also known as the retinacular arteries, traverse the superficial surface of the neck. The close proximity of these vessels to the bone makes them vulnerable to injury in any fracture of the femoral neck. The greater the displacement, the more likely that a fracture will result in compromise of the blood supply to the femoral head. The incidence of avascular necrosis (AVN) of the femoral head and nonunion is increased because of the potentially tenuous blood supply after a femoral neck fracture.
Several proposed classification schemes are based either on fracture location or on the amount of displacement of the fracture fragments. The Garden classification based on radiographic appearance is most commonly used. Stage I involves an incomplete or impacted fracture; stage II involves a complete fracture without displacement; stage III involves a complete fracture with varus displacement; and stage IV involves a complete fracture with total displacement.
Mechanism of Injury
The majority of femoral neck fractures occur in elderly patients, especially those with osteoporosis. In these patients, the usual cause of injury is minor or indirect trauma. A stress fracture that may develop in the osteoporotic femoral neck combines with a torsion injury to cause a more significant fracture. This event may actually precipitate the fall that patients associate with the fracture. The fall then often causes further displacement or comminution of the fracture. In younger patients, femoral neck fractures result from major trauma caused by incidents such as motor vehicle accidents (MVAs).
Patients with nondisplaced or minimally impacted femoral neck fractures may be ambulatory with only diffuse groin or thigh pain. Typically, a patient with a displaced fracture complains of significant hip pain, and the leg may appear slightly shortened and externally rotated. Pain is increased with any movement of the hip. Because neck fractures are intracapsular, ecchymosis is not usually present. The neurovascular status of the distal extremity is nearly always intact, so any evidence of nerve or arterial damage warrants a search for other injuries. The clinician should look for any conditions that may have precipitated a fall in the elderly patient with a hip fracture (e.g. syncope, orthostasis). In those with a stress fracture or impacted fracture, the clinical signs may be less pronounced. These patients may be ambulatory; have groin, medial thigh, or knee pain; and have no clear history of trauma. The leg is not shortened or rotated.
A true anteroposterior (AP) view with the hip in as much internal rotation as possible and a lateral view are usually adequate to diagnose a femoral neck fracture ( Figure 11-2 ). The radiographs should be examined for disruption of the trabecular pattern, cortical defects, and shortening of the femoral neck. Comparison views of the other hip may aid in the diagnosis of more subtle fractures.
The normal neck shaft angle is 45 degrees on the AP view. The normal angle of the trabecular lines from the medial femur to the head on the AP view is 160 to 170 degrees ( Figure 11-3 ). Any increase or decrease in these angles may indicate a fracture.
The proximal femur is at risk for occult fracture because of the high percentage of trabecular bone, in which disruption is more difficult to detect than in cortical bone. Occult fractures about the hip can lead to significant morbidity and mortality if left undetected; therefore, determining which patients are at risk and performing additional imaging studies in the event of negative plain radiograph findings is imperative in high-risk patients. High-risk characteristics include (1) new inability to bear weight; (2) pain with hip range of motion (ROM); (3) low-energy trauma, such as a fall from standing height; and (4) conditions leading to osteoporosis. A limited magnetic resonance imaging (MRI) scan of the hip can be used in the first 24 hours to confirm the diagnosis and is the preferred form of examination ( Figure 11-4 ). It is quick, noninvasive, and just as accurate as bone scanning. If MRI is not available, a bone scan is a useful diagnostic tool. The disadvantage of using bone scanning is that it may take up to 72 hours after the injury to get optimal results, especially in an elderly patient with osteopenia, and it has lower specificity. This delay in the diagnosis of a hip fracture may result in a longer hospital stay for the patient.
Indications for Orthopedic Referral
Although impacted or nondisplaced fractures may appear benign, they are at risk of displacement, especially with conservative treatment ( Figure 11-5 ). Nondisplaced fractures are rarely treated nonoperatively because the risk of disability, complications, and mortality is increased with conservative management. Therefore, all patients with femoral neck fractures should be referred to an orthopedic surgeon.
Especially in elderly patients, the primary care provider should coordinate the timing of surgery with the orthopedist based on the patient’s medical condition and the need for stabilization of other medical problems. In general, surgery should proceed when the patient’s condition is optimized, but the decision needs to be individualized. Patients with medical comorbidities have a significantly higher overall mortality regardless of the timing of surgery, and priority should be given to improving their medical status preoperatively at the expense of surgical delay. In young healthy patients, current best evidence shows no association between the time to surgery and the risk of AVN or nonunion, although surgery is usually performed in the first 24 hours.
The acute management of femoral neck fractures includes analgesia, assessment and stabilization of the patient’s medical condition, and prompt orthopedic consultation. Patients should receive prophylaxis against deep venous thrombosis and wound infection. The use of traction before surgery has not been shown to provide any benefit in reducing pain or improving fracture reduction.
Debate continues among orthopedic surgeons as to whether open reduction with internal fixation (ORIF) or arthroplasty is the best treatment for appropriate surgical candidates. Treatment with a total or partial hip arthroplasty allows for earlier recovery and may reduce the risk of avascular necrosis and nonunion. Nonoperative management is usually reserved for the most debilitated patients. In younger patients, achieving anatomic reduction and a stable fixation is the goal, and which technique is used and surgical timing are determined by the orthopedic surgeon. Patients with osteoporosis should receive therapy to increase bone mass and thus prevent future osteoporotic fractures.
The long-term complications of nonunion and AVN are related to the risk of injury to the blood supply of the femoral head and neck after a fracture. These complications occur more frequently in displaced fractures and in fractures in younger patients, which involve greater injury violence than does the usual fracture in an older patient. Initially, AVN may be painless but over time pain and motion limitation occurs. Radiographs should be obtained periodically for up to 3 years after injury to screen for AVN. Complications after surgical repair include failure of the fixation device, chronic pain, infection, dislocation, and posttraumatic arthritis.
By definition, an intertrochanteric fracture is extracapsular and occurs along a line between the greater and lesser trochanters ( Figure 11-6 ). Muscle attachments on the femur may cause displacement after an intertrochanteric fracture because the internal rotators remain attached to the distal fragment, and the external rotators stay attached to the proximal head and neck fragment. The vascular supply to the intertrochanteric area is usually adequate for healing because of the surrounding muscles and periosteum.
Mechanism of Injury
Intertrochanteric fractures account for almost half of all fractures of the proximal femur and occur primarily in elderly individuals. This fracture usually results from a fall involving both direct and indirect forces. Direct forces act along the axis of the femur or over the greater trochanter. Indirect forces from the pull of the iliopsoas muscle on the lesser trochanter or the pull of the abductor muscles on the greater trochanter may also cause a fracture.
Patients report hip pain, swelling, and ecchymosis. The injured leg may be noticeably shortened and externally rotated if the fracture is displaced. Any movement of the hip is painful. Distal pulses and nerve function are usually intact.
Elderly patients who have fallen and fractured a hip are at risk of dehydration if help has been delayed and they have been unable to drink fluids. Intertrochanteric fractures can cause a loss of up to 3 units of blood, which leads to intravascular volume depletion, especially when combined with dehydration. Skin breakdown is possible in the acute setting if the patient has been unable to get up from the fall for a prolonged period. After a fall, patients with osteoporosis may also have associated fractures of the distal radius, proximal humerus, ribs, or spine.
A true AP view in internal rotation and a lateral view should be obtained for a patient with a suspected hip fracture. The AP view should be examined for bone quality (trabecular architecture) and fracture displacement. The lateral radiograph is useful in determining the size, location, and comminution of the fracture fragments.
Patients with negative radiographic results and a clinical examination that suggests an intertrochanteric fracture should undergo additional diagnostic studies to confirm the diagnosis. MRI can be used if a diagnosis is imperative in the first 24 hours. A bone scan can be used to detect an occult fracture 24 to 72 hours after injury.
A number of classification systems exist for intertrochanteric fractures, but these can be simplified by distinguishing a stable from an unstable fracture. This distinction determines the possibility of obtaining an anatomic fracture reduction, as well as the risk of loss of fracture reduction after internal fixation. Stable fractures have no displacement of the lesser trochanter and no comminution, and the medial cortices of the proximal and distal fragments are aligned (i.e., no displacement between the femoral shaft and neck) ( Figure 11-7 ). Unstable fractures are comminuted, have multiple fracture lines, or are displaced, with medial displacement of the shaft occurring most frequently ( Figure 11-8 ).
Indications for Orthopedic Referral
All patients with intertrochanteric fractures should be referred to an orthopedic surgeon because the vast majority of them need operative treatment. Nonoperative management can be considered for nonambulatory or patients with dementia. The primary care provider plays an important role by informing the orthopedic surgeon of the patient’s functional status before the fracture so that an appropriate decision regarding surgery can be made.
As is the case for patients with femoral neck fractures, in the acute period, the patient’s medical condition—particularly the fluid status—must be assessed and stabilized. Analgesia and prompt orthopedic consultation are next. Although surgery can be performed within 24 to 48 hours after hospital admission, the decision regarding operative versus nonoperative treatment should be made in the acute setting.
The goal of treatment for intertrochanteric fractures is restoring the patient to his or her preinjury level of function and activity as soon as possible. A systematic review found insufficient evidence to recommend arthroplasty over internal fixation. Nonoperative treatment may be a safer and less expensive option for patients who have little or no chance to walk based on their preinjury functional level. In nonambulatory patients, the fracture itself is ignored, and the resultant deformity of shortening and external rotation is accepted. The patient is given pain medication as needed and mobilized to a sitting position within 2 to 3 days. When the pain has subsided, the patient can resume a preinjury level of care and activity. Medical therapy to increase bone mass and thus prevent future fractures should be considered for any patient with osteoporosis.
Patients with intertrochanteric fractures have an increased mortality rate in the first year after fracture. Survival is most closely related to the patient’s age and medical condition at the time of the fracture, not the method of treatment used. Complications from intertrochanteric fractures are similar to those occurring after femoral neck fractures and include infection, fixation failure, AVN, and nonunion. The incidence of nonunion and AVN is significantly lower than the incidence of these complications in femoral neck fractures because of the better blood supply in these extracapsular fractures.
Proximal femur fractures in children are rare compared with fractures in adults. They represent fewer than 1% of pediatric fractures and fewer than 1% of all hip fractures. Most orthopedic surgeons may treat only four or five of these injuries in a lifetime. When they do occur, they are usually the result of severe trauma. A hip fracture that occurs with minor trauma should arouse suspicion of a pathologic fracture or child abuse ( Figure 11-9 ). Because of the weak proximal femoral epiphysis, a transepiphyseal separation may occur after significant trauma. Nearly all hip fractures in children require surgical intervention. Complications include AVN, malunion, nonunion, and premature physeal closure.
Trochanteric fractures are usually avulsion injuries in adolescents. Fractures of the lesser trochanter are caused by avulsion of the attachment of the iliopsoas muscle when the muscle contracts forcefully in an extended leg. Greater trochanter fractures may result from avulsion of the abductor muscles (gluteus medius and minimus) or direct trauma from a fall onto the hip. An isolated fracture of the lesser trochanter in the older adult should raise suspicion of underlying metastatic disease.
Examination of the patient with a lesser trochanter fracture reveals tenderness in the femoral triangle and pain that is increased with hip flexion and rotation. Patients with a greater trochanter fracture have localized tenderness that is exacerbated by hip abduction. AP and lateral views of the hip are usually adequate to diagnose these fractures ( Figure 11-10 ). Standard radiographs should be examined to determine the amount of displacement, but internal and external rotation views may be necessary to assess this accurately. Patients with decreased bone density are at risk of extension of a trochanteric fracture into the intertrochanteric zone or femoral neck and should undergo additional imaging with an MRI to rule out this possibility.
Patients with displaced fractures (>1 cm) should be referred to an orthopedic surgeon for consideration of open reduction and internal fixation (ORIF). Nondisplaced fractures of the trochanters heal well with conservative treatment that includes bed rest until pain subsides followed by gradual ambulation with crutches. Partial weight bearing should be continued for 3 to 4 weeks or until the patient has pain-free ROM. Physical therapy should be considered to help guide the patient through a progressive exercise program. Most patients resume normal physical activity within 2 to 3 months. Repeat radiographs should be taken at 4 weeks to document evidence of callus formation. Complications from isolated trochanteric fractures are rare.
Femoral Shaft Fractures
The overall annual incidence of fractures of the femoral shaft is approximately 10 per 100,000 person-years. There is a bimodal distribution of femoral shaft fractures in both genders, with the first peak in children younger than 10 years of age and the second peak in those older than 75 years of age. Up to approximately 50 years of age, femoral shaft fractures are more common in males than females but this difference reverses in those older than 60 years of age. Mid-shaft fractures are discussed below.
The femoral shaft can be divided into three main parts: the proximal portion (femoral head and neck, intertrochanteric and subtrochanteric area); the middle portion involving the femoral shaft; and the distal portion, including the supracondylar area. The pull of the numerous muscles surrounding the femoral shaft results in displacement and angulation of the fracture fragments. The excellent blood supply to the femoral shaft, mostly from the profunda femoral artery, leads to good fracture healing, but it also accounts for significant volume loss after an acute fracture, 1000 to 1500 mL on average. The popliteal artery and vein and the tibial and common peroneal nerves are in close proximity to the distal femur and may be injured when a fracture occurs in this location.
Mechanism of Injury
A majority of midshaft femoral fractures are the result of MVA or falls from a significant height, particularly in the younger population. Low energy mechanisms include ground level falls, falls from a height of less than one meter, and sports-related injuries with direct or indirect force or muscular action. Transverse fractures result from bending forces or direct trauma. Spiral fractures result from torsional force—the greater the force, the greater the degree of comminution and displacement. Pathologic fractures of the femur after minor trauma are associated with metastatic disease or, in rare cases, primary tumors such as osteogenic sarcoma ( Figure 11-11 ).