Hip fractures in children

INTRODUCTION — This topic will review issues related to hip fractures (proximal femur and femoral neck fractures) in children. Slipped capital femoral epiphysis (SCFE), femoral shaft fractures, and pelvic avulsion fractures in children are discussed separately:

●(See "Evaluation and management of slipped capital femoral epiphysis (SCFE)" and "Femoral shaft fractures in children".)

●(See "Femoral shaft fractures in children".)

●(See "Pelvic trauma: Initial evaluation and management", section on 'Avulsion fractures'.)

CLASSIFICATION — Pediatric hip fractures can be divided into four types as first described by Delbet (figure 1) [1-4] as follows:

●Type I: Transepiphyseal – These are fractures through the proximal femoral physis, and represent Salter-Harris type I fractures of the proximal femur [3]. Subtypes are IA (without dislocation) and IB (with dislocation) (figure 1). These are the least common types of hip fracture in children, accounting for <10 percent of these fractures [1,3,5-7]. Transepiphyseal fractures occur more commonly in young children and infants. In neonates they are equivalent to "proximal femoral epiphysiolysis," resulting from difficult delivery [1,3]. These fractures are also associated with femoral head dislocations [8]. In children under two years of age, the presence of a transepiphyseal fracture should prompt an evaluation for nonaccidental trauma when a history of trauma is lacking or of insufficient force to explain the degree of injury.

●Type II: Often identified as the most common type of pediatric hip fracture extends through the mid-portion of the femoral neck and is found in 40 to 50 percent of children [1,3,5-11].

●Type III: Cervicotrochanteric – This fracture occurs through the base of the femoral neck and is seen in 25 to 35 percent of children with hip fractures [1,3,5-10].

●Type IV: Intertrochanteric – This fracture between the greater and lesser trochanters accounts for up to half of all pediatric hip fractures and has the best outcome [1,3,5,8,12].

This classification, along with other factors, helps determine operative versus nonoperative therapy. It also predicts the risk of avascular necrosis of the femoral head which is greater for patients with type I or type II fractures [10]. (See 'Definitive care' below and 'Complications' below.)

Type II and type III fractures are both subtypes of pediatric hip fractures known as "femoral neck fractures."

Stress fractures of the proximal femur are uncommon but do exist and do not fall into the Delbet classification scheme. They will be discussed separately. (See 'Stress fractures of the hip' below.)

CLINICAL ANATOMY — The femur is the largest bone in the body. The femur joins with the acetabulum of the pelvis proximally to form the hip joint and with the patella, tibia, and fibula distally to form the knee joint.

The pediatric femur can be divided anatomically into the following regions (figure 2):

●Hip or proximal femur (made up of the femoral head, femoral neck, and greater and lesser trochanter),

●The femoral shaft

●The distal femur (made up of the medial and lateral epicondyles, the medial and lateral condyles, and the trochlea).

Pertinent for pediatric patients, the femur can also be divided into its developmental components. At birth, a single proximal physis is present, which then separates into two discrete physes (capital femoral and greater trochanteric), occurring between four and six months and four years of age, respectively. These physes fuse around the age of 14 in girls and around the age of 16 in boys (figure 3) [1,3]. The persistence of these physes into late adolescence coupled with a weak blood supply make the immature hip vulnerable to growth abnormalities following fractures.

The high rate of complications associated with hip fractures is directly related to its tenuous blood supply. The two branches off the profunda femoris artery, the medial and lateral circumflex arteries, provide the primary blood supply to the head of the femur until about age four (figure 4). The medial circumflex artery runs anterior to the femoral neck; the lateral circumflex artery runs posterior to the femoral neck. This initial blood supply is replaced by lateral epiphyseal vessels which consist of two branches, the posterosuperior and posteroinferior branches, off the medial circumflex artery. These two branches provide the sole blood supply to the head of the femur into adulthood. Direct damage to either or both of these vessels can lead to avascular necrosis of the femoral head and permanent disability [1,3,13]. These vessels are also extremely susceptible to tamponade from hemarthrosis secondary to intracapsular fracture.

MECHANISM OF INJURY — Hip fractures, also known as proximal femoral fractures, are uncommon in children, accounting for <1 percent of all pediatric fractures [1-3,9,12].

The pediatric hip is strong and, with the exception of the physis, requires high-energy forces to fracture. Thus, the majority (85 to 90 percent) of pediatric hip fractures occur as a result of high-energy trauma. Examples include motor vehicle collisions, falls from a height or a bicycle, pedestrians struck by automobiles, or sports injuries [1,3,5,7,10,11,14,15]. Similar fractures in an adult or older adult population may result from minor trauma. Hip fractures in children under two years of age without a history of major trauma should raise concern for child abuse given the large force needed to cause this injury [1,3,16].

Minor trauma can result in hip fracture if there is a pre-existing pathologic lesion. Some of the more common pathologic conditions include unicameral (simple) bone cyst, osteogenesis imperfecta, fibrous dysplasia, and secondary osteopenia (eg, patients with myelomeningocele or cerebral palsy) [1,3,8,14].

CLINICAL PRESENTATION AND EXAMINATION — In most cases, the diagnosis of a hip fracture is easily made based on the mechanism of injury and presence of significant pain in the hip. If the fracture is displaced, the affected leg will often be externally rotated and shortened [1,3]. In addition, palpation of the hip typically causes significant pain and the range of motion is markedly limited [3].

For younger children with nondisplaced fractures (eg, stress fractures or incomplete hip fracture), physical findings are often subtle and include limp and knee pain or hip pain on extremes of range of motion, particularly internal rotation [1]. Careful physical examination is necessary to avoid missing these important findings.

A complete neurovascular exam distal to the site of the fracture is necessary to ensure that the displaced fracture has not damaged nerves or arteries.

Hip fractures are a marker of high-energy trauma and are often associated with other musculoskeletal injuries such as hip dislocations, pelvic fractures, and femoral shaft fractures, as well as major trauma to the abdomen, pelvis, and head [1,3,9,11,17,18]. Thus, a child with a hip fracture warrants a trauma evaluation according to the principles of Advanced Trauma Life Support. (See "Trauma management: Approach to the unstable child", section on 'Primary survey' and "Trauma management: Approach to the unstable child", section on 'Secondary survey'.)

RADIOGRAPHIC FINDINGS — Initial evaluation for a hip fracture consists of standard anterior-posterior (AP) and lateral radiographs of the affected hip (image 1). These radiographs may be adequate to demonstrate the fracture, especially if it is displaced. The radiograph will identify the type of fracture, the direction of the fracture line, the amount of displacement, the degree of angulation, and the location of the femoral epiphyses [1,3]. This information will be needed by the orthopedic surgeon to guide management. (See 'Classification' above and "General principles of fracture management: Fracture patterns and description in children", section on 'Fracture description in children'.)

Nondisplaced or stress fractures are often more difficult to see on plain AP and lateral radiographs. Depending on the level of clinical suspicion, more advanced imaging such as a bone scan, computed tomography (CT), or magnetic resonance imaging (MRI) may be needed to identify these fractures [1,3]. MRI has the advantage of no radiation exposure but requires sedation or general anesthesia for successful completion in infants and young children. An orthopedist with pediatric expertise or a pediatric radiologist should assist in choosing the optimal imaging study in a given patient.

INITIAL TREATMENT — All proximal femur fractures require urgent and at times emergency, surgical treatment [1].

Stabilization — Children with high-energy trauma (eg, high-speed motor vehicle collision) associated with hip fractures should be rigorously evaluated by standard trauma guidelines, including establishment of an airway, evaluation for pulmonary compromise, and rapid treatment of hemorrhagic shock. (See "Trauma management: Approach to the unstable child".)

For children with an isolated hip fracture and no other serious injury, initial therapy consists of pain management and immobilization.

Analgesia — Parenteral analgesia (eg, intravenous morphine or fentanyl) is most appropriate for initial pain control in children with hip fractures and should be given as soon as possible in the hemodynamically stabile child.

Immobilization — Once distal neurovascular function has been tested and evaluation for open wounds of the skin is complete, all hip fractures should be immobilized for comfort. Plaster, fiberglass, and various prefabricated splints are commonly used to provisionally stabilize the fracture.

Splints work best when immobilizing both the hip and the knee. Consequently, placing splints laterally from the iliac crest to the ankle is quite effective. Splints can be further bolstered, or even substituted, by pillows, blankets, or other types of bulky padding. Distal femoral traction is also a viable option, and may be more appropriate in older children, or when care may be delayed or mandates access to the affected extremity.

Paramedical staff will frequently use traction splints to stabilize suspected femoral fractures in the field. These traction splints should be removed as soon as possible after arrival in the emergency department to prevent pressure ulcers from developing where the splints compress the skin. The traction splint should be replaced by a padded provisional splint or traction as described above.

Provisional reduction — With the exception of extremely rare cases of open fracture or ensuing neurovascular compromise, provisional manipulation or reduction of hip fractures is not warranted.

Emergency decompression — In order to prevent compromise to the precarious blood supply of the femoral head [19-23], we suggest that children with Delbet types I, II, or III displaced hip fractures undergo emergency decompression of intracapsular hematoma by an orthopedic surgeon with pediatric or trauma expertise. If appropriate orthopedic care is not locally available, this treatment may require emergency transfer.

In a small observational series in which all patients with displaced hip fractures received hip capsule decompression by large bore needle aspiration or open reduction within 24 hours, none of the 10 children developed avascular necrosis (AVN) of the femoral head [19]. By contrast, AVN occurred in 17 to 43 percent of children who did not undergo emergency decompression in prior case series [8,24,25]. In a separate retrospective study of 44 children with hip fractures, however, there was no difference in rates of osteonecrosis for patients who underwent capsular decompression compared with those who did not [26]. Furthermore, time to reduction (greater than or less than 12 hours) did not affect the risk of osteonecrosis either, but age greater than 11 years was associated with an increased risk of osteonecrosis.

Child protection — Diagnosis of a hip fracture in a child, especially a nonambulatory infant, with a questionable mechanism of injury should prompt involvement of an experienced child protection team (eg, social worker, nurse, physician with more extensive experience in the management of child abuse), if available. When abuse is suspected, mandatory reporting to appropriate governmental authorities is also required in many parts of the world (including the United States, United Kingdom, and Australia). (See "Child abuse: Social and medicolegal issues", section on 'Reporting suspected abuse'.)

In addition, the medical care team should ensure that children under two years of age with suspected intentional trauma undergo fundoscopic examination by an ophthalmologist to assess for retinal hemorrhages and skeletal survey to identify other injuries once the patient's clinical status is stabilized. The safety of other children in the home must be ensured by local Child Protective Services. (See "Physical child abuse: Diagnostic evaluation and management" and "Child abuse: Eye findings in children with abusive head trauma (AHT)".)

INDICATIONS FOR ORTHOPEDIC CONSULT OR REFERRAL — All pediatric hip fractures warrant orthopedic consultation. Displaced pediatric hip fractures are true surgical emergencies that require rapid management by an orthopedist with pediatric or trauma expertise.

DEFINITIVE CARE — Definitive care for hip fractures in children and adolescents is almost always operative. Typically, rigid internal fixation is applied, often augmented by a cast [22,27,28]. The timing of operative repair depends on the type of hip fracture and the patient's clinical status but should occur as soon as possible and ideally within 24 hours, especially in children with displaced fractures [2,19,27-30]. Operative treatment may consist of closed reduction and percutaneous screw fixation (image 2), or a sliding hip screw or locking plate construct. For Delbet type IV fractures, fixation options may also include a trochanteric entry rigid intramedullary nail or even retrograde flexible nails with fixation into the femoral neck and greater trochanter [31,32]. Because the risk of serious complications, including avascular necrosis of the femoral head, increases if the reduction is inadequate, pediatric orthopedic surgeons have a low threshold for open reduction using an anterolateral approach to the hip joint [33].

Infants and toddlers under two years of age often have good outcomes with nonoperative treatment [1,2,33]. Treatment options include spica cast immobilization (picture 1), splinting, traction, and Pavlik harness [34,35].

FOLLOW-UP CARE — Children with proximal femur fractures need to be followed by an orthopedist with pediatric expertise for at least one year after injury. Most cases of osteonecrosis will present within the first 9 to 12 months but may be seen as early as six weeks post injury [36]. Patients can expect to be strictly non-weight bearing for at least six weeks of recovery and may be restricted for as long as 12 weeks or more.

Physical therapy is helpful in all patients to assess ambulatory safety and provide appropriate equipment such as crutches, a walker, or a wheelchair, as indicated. Regular postoperative radiographs to assess healing and the development of osteonecrosis, malunion, or physeal arrest are mandatory. Typically, patients undergo imaging at six weeks and at three, six, nine, and 12 months after injury.

COMPLICATIONS — Complications of proximal femur fractures occur frequently and often result in very significant long-term disability [11].

●Avascular necrosis of the femoral head – Avascular necrosis (AVN or osteonecrosis) of the femoral head is the most debilitating complication of pediatric hip fractures (image 3). The risk for avascular necrosis of the femoral head depends on several variables: the type of fracture, the age of the patient, the amount of displacement, quality of fracture reduction and possibly, the time to surgery or whether hemarthrosis decompression is performed at the time of fracture reduction and fixation [19-22,28,33,37]. Risk is increased in patients with Delbet type I and II fractures [7], those over 12 years of age, those who do not receive emergency decompression, and those whose definitive treatment occurs more than 36 hours after injury [20,22,27,28,30].

AVN of the femoral head may become radiographically evident as early as six weeks post injury or as late as one to two years [36]. The vast majority of cases are evident by 9 to 12 months. Restricted weight bearing and, ultimately, subtrochanteric osteotomy may be required for treatment of AVN [33]. Intravenous bisphosphonate therapy for post-traumatic AVN is currently under investigation [38].

●Inadequate healing – Malunion or nonunion occurs in 10 to 30 percent or 6 to 12 percent of pediatric hip fractures, respectively. They are thought in some cases to result from inadequate reduction or loss of fixation [30,33,36]. A more vertical orientation of the fracture line and the use of a cast without internal fixation may also contribute to the risk of malunion or nonunion [8]. Malunion is generally manifested as a varus deformity of the femoral neck (coxa vara) [36]. Nonunion may lead to further complications such as osteonecrosis or coxa vara, as well as prolonged disability due to pain. Coxa vara results in poor hip mechanics with associated pain and weakness during ambulation. Valgus subtrochanteric osteotomy is often required for treatment of these complications [8,33].

●Physeal arrest – Physeal arrest occurs most commonly in type I (transepiphyseal) hip fractures, and almost always occurs in the presence of AVN of the femoral head. Limb-length inequality may result from complete closure of the physis, and can be quite profound in the presence of AVN [24,39]. Secondary deformity from physeal arrest is uncommon. Long-term management of limb-length discrepancy is dependent upon the magnitude of the resultant difference and is beyond the scope of this discussion.

●Osteomyelitis or joint infection – Infection is uncommon after hip fracture and is generally manifested as persistent hip pain and fevers. Infection is associated with an even higher risk of AVN [10].

RETURN TO SPORT OR WORK — Typically, full weight bearing, without the need for assistive devices, does not occur until about 12 weeks after injury. This time course extends significantly with the development of complications. Minimum criteria for return to play are a radiographically healed fracture that is pain free. Return to sport should not be allowed until near complete muscular control and absence of limp occurs. As such, the earliest return to play is typically about four to six months post-injury, and return to sport, in an uncomplicated course, is generally at least six months.

Physical therapy is often helpful early in the postoperative course for gait training with assistive devices but is otherwise not usually required.

STRESS FRACTURES OF THE HIP — Stress fractures of the hip are unusual in children and do not fall into the Delbet classification described above (image 4) [40,41].

These injuries are more common in adolescents and generally occur after a history of minor injury or repetitive activities such as long-distance running [25,40]. As in adults, stress fractures can be difficult to diagnose given the vagueness of the symptoms associated with the injury. The patient may have limited pain and be generally functional despite the fracture [3,42]. With stress fractures of the femoral neck, the patient may have anterior groin (inguinal) pain [25]. The stress fracture may not be evident on plain anterior-posterior (AP) and lateral radiographs of the hip and may require bone scan [40] or magnetic resonance imaging (MRI) to diagnose [1,3,25,41]. In general, the treatment involves rest and supportive care. Early recognition and adherence to activity restriction is necessary to prevent stress fractures from progressing to complete fractures or causing avascular necrosis of the hip [3,40]. (See "Femoral stress fractures in adults".)

Stress fractures of the hip are rare in young children. Limited evidence from case series and case reports suggest that younger children may have a different presentation for femoral stress fracture than adolescents that is characterized by chronic limp and pain-free full range of motion or pain only present on terminal hip flexion on physical examination [42,43]. A high index of suspicion and imaging as described above is necessary to identify these fractures.

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of acute fracture management".)

●(See "General principles of definitive fracture management".)

●(See "General principles of fracture management: Early and late complications".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General management of pediatric fractures" and "Society guideline links: Lower extremity fractures in children" and "Society guideline links: Acute pain management".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Hip fracture (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Mechanism of injury – Hip fractures, also known as proximal femoral fractures, are uncommon in children , accounting for <1 percent of all pediatric fractures. (See 'Mechanism of injury' above.)

The pediatric hip is strong and, with the exception of the physis or preexisting pathologic lesion (eg, unicameral bone cyst, secondary osteopenia due to cerebral palsy), requires significant forces to fracture. Thus, the majority of pediatric hip fractures occur as a result of high-energy trauma. (See 'Mechanism of injury' above.)

Displaced hip fractures in children under two years of age without a history of major trauma should raise concern for child abuse given the large force needed to cause this injury. (See 'Mechanism of injury' above.)

●Clinical presentation – Hip fractures in children, with the exception of stress fractures, typically have the following clinical features (see 'Clinical presentation and examination' above):

•High-energy mechanism of injury

•Hip pain

•External rotation and shortening of the affected leg

●Imaging and classification – Initial evaluation for a hip fracture consists of standard anterior-posterior (AP) and lateral radiographs of the affected hip (image 1). (See 'Radiographic findings' above.)

Pediatric hip fractures can be divided into four types as first described by Delbet (figure 1). This classification predicts the risk of avascular necrosis of the femoral head. (See 'Classification' above and 'Complications' above.)

●Stabilization and initial treatment – Children with hip fractures require a trauma evaluation and management according to the principles of Advanced Trauma Life Support. (See "Trauma management: Approach to the unstable child", section on 'Primary survey' and "Trauma management: Approach to the unstable child", section on 'Secondary survey' and 'Stabilization' above.)

For children with an isolated hip fracture and no other serious injury, initial therapy consists of pain management and immobilization. (See 'Initial treatment' above.)

●Child protection – Diagnosis of hip fracture in children less than two years of age with a questionable mechanism of injury should prompt involvement of an experienced child protection team (eg, social worker, nurse, physician with more extensive experience in the management of child abuse), if available. In many parts of the world (including the United States, United Kingdom, and Australia), a mandatory report to appropriate governmental authorities is also required for cases of suspected abuse. (See "Child abuse: Social and medicolegal issues", section on 'Reporting suspected abuse'.)

●Specialty consultation – Pediatric hip fractures are considered true surgical emergencies. All such injuries should be managed emergently by an orthopedist with pediatric expertise. (See 'Indications for orthopedic consult or referral' above.)

●Emergency decompression and definitive care – We suggest that children with Delbet types I, II, or III displaced hip fractures undergo emergency decompression of intracapsular hematoma by an orthopedic surgeon with pediatric expertise (Grade 2C). If appropriate orthopedic care is not locally available, this treatment may require emergent transfer. (See 'Emergency decompression' above.)

Definitive operative care for hip fractures in children depends upon the age of the child and the type of injury. (See 'Definitive care' above.)