Chapter 31: Injuries of the Pelvis and Lower Extremities

• Reduction of a hip dislocation should take place within 12 hours after the injury.

• Slipped capital femoral epiphysis (SCFE) is a disruption of the capital femoral physis that can occur over time.

• Legg–Calvé–Perthes disease is an idiopathic avascular necrosis (AVN) of the femoral head.

• A spiral femur fracture in a nonambulatory infant or child suggests child abuse.

• Distal femoral epiphyseal fractures in children can cause growth disturbances in the lower extremity.

• Spiral tibial shaft fractures are termed toddler's fracture in those just learning to walk.

• The most common fracture of the talus is in the neck, which occurs from forced dorsiflexion. This injury is often complicated by AVN.

• Lisfranc fracture occurs at the base of the second metatarsal, where the stability of the midfoot is maintained.

• The Jones' fracture is a metatarsal neck fracture distal to the apophysis of the base of the fifth metatarsal.

The young pelvis has a tremendous amount of cartilage and pliability and can absorb tremendous amounts of energy without resulting in a fracture. Pelvic fractures in children usually require high-energy trauma such as automobiles versus pedestrians, motor vehicle crashes, or significant falls. The violent forces required to cause pelvic fractures often result in multisystem trauma accompanied by visceral organ damage, limb fractures, urogenital injuries. Morbidity and mortality rates following pelvic fractures in children are much better than those seen in adults. The effect of obesity in children has also shown that obese youth are more likely to suffer pelvic injuries if BMI ≥95%.¹

The recognition and stabilization of any accompanying injuries is the most pressing issue surrounding pelvic injuries in the emergency department (ED). Pelvic fractures resulting from high energy are classified depending upon their involvement of either the pelvic ring or the acetabulum. Pelvic ring fractures can be classified as either stable or unstable. Stable injuries include single breaks in the pelvic ring, diastasis of the pubic symphysis, and fractures of the iliac wings. Unstable injuries include those with two breaks of the pelvic ring (Fig. 31-1) or those having a sacroiliac dislocation/fracture along with an associated rami or pubic symphysis fracture. Stable fractures may be successfully managed nonoperatively. Unstable fracture patterns may require external fixation or open reduction/internal fixation to stabilize the bony injury while allowing for better management of associated injuries.

Fractures of the acetabulum are very rare in children and result from forces transmitted through the femoral head. The acetabulum will usually fracture where the triradiate cartilage meets the pelvis (Fig. 31-2). Like pelvic ring fractures, these injuries are usually associated with high-energy trauma. Any acetabular fracture also associated with a pelvic ring fracture must be considered unstable. Many acetabular fractures are associated with hip dislocations. Dislocations of the hip may still be evident in the ED, or they may spontaneously reduce before presentation. Occasionally, acetabular fractures can occur following lower-energy trauma, such as a sports-related hip dislocation.

Evaluating any pelvic injury begins with a history followed by a close inspection for any asymmetry, ecchymosis, or abrasions to the pelvis. Pain or crepitus elicited by compressing the iliac crests or by putting direct pressure on the pubic symphysis suggests a possible pelvic ring or acetabular fracture. Because of the association with multisystem trauma, a thorough physical examination of the head, abdomen, urogenitals, and rectum should be performed. AP radiographs of the pelvis use to be part of many trauma protocols, but may be unnecessary unless there is a high-risk mechanism of injury, hematuria, or findings such as pain, ecchymosis, or abrasions on pelvic/genital/abdominal examination.² If a lateral view is also desired, the cross-table lateral view is preferred over the frog-leg view in acute trauma because further displacement is a risk. CT scans are more sensitive than radiographs for detecting pelvic fractures, so radiographs may be omitted whenever abdominopelvic scans are indicated.

Pelvic fractures in children may have good outcomes with conservative, nonsurgical management. Morbidity is closely related to the number and severity of associated multisystem injuries. Management in the ED focuses on stabilization of the associated injuries and controlling any signs of hemorrhage. Consult orthopedics emergently if the fracture is open, unstable, or the hemorrhaging is difficult to control. Orthopedics may elect to place an external fixator for temporary stabilization. Younger children with unstable fractures may be admitted for bed rest, but adolescents often require open reduction and internal fixation. Stable fractures of the pelvis can be treated with bed rest and nonweight bearing for 4 to 6 weeks.

Avulsion fractures of the pelvis are very common in adolescents and occur at the site of pelvic apophyses where muscle attaches to immature bone. Avulsions frequently occur with adolescents playing sports (Fig. 31-3), and the history usually involves a sudden, explosive activity. Frequent avulsions and their associated attachments are the iliac crest (tensor fascia), anterior inferior iliac spine (rectus femoris), anterior superior iliac spine (sartorius), and the ischium (hamstrings). Avulsion injuries are suspected with appropriate history and point tenderness over specific landmarks such as the iliac crest, iliac spine, or ischium. Avulsion fractures typically heal very well and require only protected weight bearing for 2 to 4 weeks with a gradual progression back to ambulation and activities. It is extremely rare for avulsions to require surgical fixation.³

Dislocations of the hip are rare events in pediatrics and account for less than 5% of dislocations. Unlike in adults, the forces required for dislocation in young children are less violent because of the increased joint laxity and shallow nonossified acetabulum. The mechanism in younger children may even be trivial falls or sporting injuries, so a high index of suspicion is warranted.⁴ Once the acetabulum deepens and ossifies during adolescence, much stronger forces are then required to dislocate the hip. Hip dislocations are described based on where the femoral head lies in relation to the pelvis, and more than 90% of the time hip dislocations are posterior in nature. Fracture-dislocations of the hip involving the proximal femur or acetabulum occur less commonly than in adults.⁵

Most hip dislocations present to the ED in severe discomfort with a shortened leg, flexed hip, and internal rotation. Dislocations that reduce spontaneously before ED presentation are diagnostically challenging, but should always be considered with an acute hip injury. After thoroughly palpating the pulses and assessing neurologic function, imaging begins with an AP radiograph of the pelvis. Radiographs should be reviewed closely for asymmetric joint spacing or possible acetabular and femoral neck fractures. Any suspicious findings warrant further radiographs or a CT scan to determine the extent of injury. Closed reduction may be performed in the ED or operating suite using procedural sedation and muscle relaxants. One technique for reducing a posterior dislocation involves flexing the hip and knee to 90 degrees before applying axial traction to the thigh. A postreduction CT scan of the hip is recommended to look for any intra-articular fractures or fragments along with judging the adequacy of the reduction. If the dislocation cannot be easily reduced, or is accompanied by a proximal femur or acetabular fracture, then open reduction and fixation is clearly preferred. All reductions should occur within 6 hours of the injury to decrease the risk of avascular necrosis (AVN) and osteoarthritis. Delays in reduction also make the procedure much more difficult. Bed rest, immobilization, and close follow-up are recommended for at least 6 weeks once the dislocation is reduced.⁶

Proximal femur fractures are very rare in pediatrics and account for less than 1% of fractures around the hip. Proximal femur fractures can occur at the physis, neck, or trochanteric region depending upon the forces involved. These fractures are complicated by the high risk of premature physeal closure or AVN of the femoral head. The risk is greatest with displaced transphyseal fractures, which must be differentiated from slipped capital femoral epiphysis (SCFE) as they are similar in appearance on x-ray. Despite their radiographic similarity, their presentations are distinctly different. Transphyseal fractures present in younger children following a significant trauma, and SCFEs traditionally present subacutely in obese teenagers without a major traumatic event. Any proximal femur fracture demands orthopedic consultation in the ED due to the high risk of complications and likely need for surgical fixation.⁶

Similar to the pelvis, the proximal femur may also have avulsion fractures of the apophyses where large muscle groups attach to the greater or lesser trochanter. Adolescents doing sporting activities may violently contract the iliopsoas avulsing the lesser trochanter or contract the hip abductors which can avulse the greater trochanter. Like pelvic avulsions, these injuries usually do well with conservative management and progressive weight bearing over 4 weeks. In rare instances, the avulsed fragment may be significantly displaced requiring open reduction and fixation.

Most pediatric femur fractures involve the femoral shaft. Femoral shaft fractures are classified and managed based upon the patient's age. The most common site of fracture along the shaft is the middle third, but the proximal and distal third also occur regularly. Unlike adult femur fractures, the pediatric patient rarely experiences hypotension or shock due to an isolated femur fracture. If shock-like symptoms are present, look closely for an accompanying injury. In adolescents, where high-energy trauma is usually the mechanism, always evaluate closely for injuries to the visceral organs.

If a femur fracture is suspected, splint the leg immediately following any necessary resuscitation, assessment of the distal pulses, and testing of the distal nerves. Splinting and pain control are often very helpful before radiographs are taken. Obtain radiographs of the entire femur, along with hip and knee radiographs, looking for accompanying dislocations or injuries. Because of the intense amount of pain with femur fractures, patients may not localize pain as well as with other extremity fractures. Closely monitor distal pulses and distal nerve function during observation, and consult orthopedics. Hospital admission for pain control, observation, and definitive management is typical.

The nonambulatory infant with a femur fracture should raise concerns of nonaccidental trauma though no particular fracture pattern is pathognomonic whether the fracture is spiral or transverse in nature. Most experts also recommend a skeletal survey as part of the evaluation in infants with a femur fracture. Thankfully, the young patient with a femur fracture has a tremendous ability to remodel and heal well without surgical intervention, so most do well in either a hip spica cast or Pavlik harness.

Older toddlers and preschool children increasingly suffer femur fractures from automobile versus pedestrian accidents, but they may also sustain femur fractures from falls during normal childhood activity.⁷ If high-energy forces are involved, look carefully for any concomitant, life-threatening injuries. Once stabilized in the ED, management is usually closed reduction with spica casting, while surgical fixation is rarely necessary in this age group. Recent studies also suggest a single-leg hip spica cast may offer numerous benefits over double-leg spica casts without any differences in outcomes.⁸

School-aged children and adolescents typically present with femur fractures following high-energy trauma such as automobile accidents. The larger, stronger muscle groups in these patients increase the risk for limb shortening and malunion after reduction, so these injuries are now managed with surgical placement of either an intramedullary rod or flexible “Nancy” nail. This older age group used to be managed with weeks of prolonged traction, but most are now managed surgically soon after the time of injury.⁹

Injuries of the knee and patella are frequently seen following sports injuries, falls, and auto versus pedestrian accidents. Fractures about the knee are worrisome because two-thirds of the lower extremity length comes from the physes of the distal femur and proximal tibia. This results in a high risk of growth arrest or progressive deformity with such fractures. The stage of skeletal maturity plays a large role in injury patterns. The knee is a hinge joint consisting of strong ligaments attached to growing bone near the physis. When the knee is injured, either the surrounding ligaments or the physis may be injured depending upon the stage of skeletal maturation. This makes diagnosis and evaluation challenging. Remember, fractures are more common in the younger patient, but ligamentous injuries are increasingly prevalent in adolescents.

Fractures of the distal femoral physis are rare but complications are not. Injuries to the distal femur physis is caused by motor vehicle accidents or sports. Salter–Harris (SH) II fractures are the most common fracture pattern with the metaphyseal fragment sometimes difficult to recognize. These injuries, along with SH III and SH IV fractures, often require reduction and occasional pinning to ensure anatomic alignment and decrease the risk for subsequent arthritis or growth delay. Nondisplaced SH I fractures may be managed with immobilization in a nonweight-bearing long-leg posterior splint, but even with proper management, a large number of distal femoral physeal fractures still go on to experience growth disturbances.¹⁰

The proximal tibial physis is injured less frequently because it has increased anatomic stability from the collateral ligaments which insert distal to the physis and offer some “protection” by transmitting forces away from the physis. But as adolescents mature, the tibia also develops some rather unique injury patterns due to the increasing muscle mass and attachments to immature bone. The first unique injury involves avulsion of the tibial spine (tibial eminence or plateau) from similar forces (hyperextension, sports, etc.) that would rupture the anterior cruciate ligament (ACL) in adults. In some children and adolescents, the stronger ligamentous attachment actually avulses off part of the tibia plateau at the site of attachment (Fig. 31-4). The second unique injury pattern involves the tibial tubercle when a forceful contraction of the adolescent quadriceps can actually pull on the tibial tubercle enough to cause an avulsion during explosive, sporting maneuvers. This avulsion of the tibial tubercle may extend up into the tibial physis or all the way into the articular surface of the knee depending upon the forces involved and the stage of skeletal maturity (Fig. 31-5).

Fractures of the patella are much less common in children than in adults. The growing patella is covered by a large amount of cartilaginous tissue that acts as padding against direct trauma. The most common patella fracture pattern is transverse (Fig. 31-6) from a direct blow. Patella fractures should not be confused with the 5% of the population that have a nonpathologic bipartite patella in the superolateral corner of the patella (Fig. 31-7). The history easily differentiates these two radiographic similarities since a patella fracture results from an acute injury versus a bipartite patella which is usually asymptomatic or chronic in nature. Adolescents develop unique injuries called “sleeve” fractures when the patella tendon avulses off a small “sleeve” of the inferior patella after a strong contraction of the quadriceps. These avulsed fragments may initially appear small, but they often contain a larger piece of radiolucent cartilage requiring surgical repair.

Evaluation of any knee injury begins with a good history focused on identifying the mechanism. Examination proceeds with the awareness that displaced physeal injuries, fractures, and knee dislocations can sever the popliteal artery, so assessment of the distal pulses is essential. The femur, tibia, patella, physes, and collateral ligaments should all be palpated separately to determine any point tenderness. When indicated, radiographs should include an AP, lateral, and patella view. Even if x-rays are negative, any patient with significant tenderness over the physis or a traumatic effusion needs to be immobilized, nonweight bearing, and closely followed up by an orthopedist in 3 to 5 days. Acute traumatic effusions are always hemarthroses and significant intra-articular pathology ranging from missed fractures to tears of the ligaments or menisci are frequently diagnosed at follow-up.¹¹

Femur-on-tibia knee dislocations are extremely rare in children and usually result from motor vehicle accidents. One has to be suspicious with any acute, traumatic knee effusion because of the high risk of popliteal artery damage (40%) and peroneal nerve injury (33%) which can be limb-threatening. All femur-on-tibia knee dislocations need prompt orthopedic consultation, reduction with sedation and analgesia, and admission for frequent neurovascular checks.

Unlike the rare femur-on-tibia dislocation, patellar dislocations occur regularly in adolescents and are frequently associated with sporting activities. Over 90% of patella dislocations result in lateral displacement of the patella, and spontaneous reduction frequently occurs before ED presentation with extension of the knee voluntarily or during transport. If the patella remains displaced, then prompt reduction should take place with analgesia and sedation, if necessary. Spontaneously reduced patellar dislocations must be suspected if history suggests a noncontact, twisting motion and patellar apprehension is evident on examination. Once a patella is reduced, postreduction radiographs and immobilization in extension are appropriate. Follow-up within 1 week is recommended if a large, traumatic effusion is present because many of these patients will go on to have osteochondral fragments from shearing of the patella or femoral condyle which may not be evident on initial examination and x-rays.¹¹

Nonphyseal fractures of the tibia and fibula are common long-bone fractures in the lower extremity of children. The only long bones more commonly fractured than the tibia are the forearm and humeral supracondyle. Both bone fractures of the tibia and fibula are not uncommon but require high-energy forces. Isolated tibia fractures usually result from lesser rotational or indirect forces. Fibula fractures are rare in isolation unless the mechanism is a direct blow. The fibula may be involved with some unique fracture patterns such as plastic deformation accompanying tibial fractures. Also beware of the “isolated” proximal fibula fracture on x-ray because it often occurs in conjunction with a distal tibial physeal fracture. Most fractures of the tibia and fibula require involvement of an orthopedist but may be managed in the ED with closed reduction unless an open wound, comminution, or significant displacement is present. Be cautious about potential compartment syndrome in tibia fractures and warn families about worsening pain.¹²

Fractures of the proximal tibial metaphysis and diaphysis (Fig. 31-8) demand special attention because of the high risk for compartment syndrome and limb ischemia. If the proximal tibial metaphysis or diaphysis is displaced, the tibial arteries can be damaged or severed as they run along the bone surface. There is a high risk for compartment syndrome or ischemia of the lower leg. Proximal tibia metaphyseal and diaphyseal fractures require orthopedic consultation and frequent neurovascular checks.

A greenstick fracture of the tibial metaphysis requires careful attention because of its propensity to heal with a valgus deformity. Initial x-rays may be unimpressive and the child may even be immobilized without reduction. Trouble arises because many of these fractures are actually in a slight valgus position which worsens during healing. As a precaution, greenstick fractures of the tibial metaphysis are best managed by completing the fracture and performing a reduction under anesthesia.

The toddler's fracture is an occult tibia fracture often presenting to the ED as a young child limping or refusing to walk with a rather unimpressive examination. The history may be trivial or often unwitnessed in younger children. The examination should include the entire extremity from the hip to the foot, but findings are frequently absent or very subtle. X-rays should include an oblique view. If an occult toddler's fracture is suspected, discharge with long-leg immobilization and orthopedic follow-up. The occult toddler's fracture often becomes more apparent on radiographs as new bone callous formation is seen. The presence of other symptoms in a child refusing to ambulate such as fever, erythema, or accompanying illness should prompt additional evaluation.¹³

Ankle injuries are very common in the ED, and the forces generated in young patients are quite similar to those seen in adults. The greatest difference is the immature physis, which is the “weak link” of the bony and ligamentous junction. Frequently, the mechanism of injury is inversion, which leads to ankle sprains in adults and older adolescents, but results in fibular physeal fractures of younger patients. The distal tibia and fibula physes rank third behind the phalanges and distal radius in numbers of physeal fractures. The foot also has to be examined closely with any ankle injury because concomitant fractures do occur.

Inversion and supination of the ankle often results in SH I or SH II fractures of the distal fibular physis. The SH I is the most common fracture of the ankle, and may often be overlooked because x-rays may appear normal with the only findings being tenderness over the physis and mild lateral swelling. If there is greater than 1 cm of swelling over the distal tibial or fibular physis, it is an SH I fracture.

Avulsions of the distal fibula are also seen following a similar mechanism. Isolated distal fibular fractures can be managed with crutches and an ankle stirrup (sugar-tong) splint, walking boot, or air stirrup depending upon the degree of injury.¹⁴ Displaced fibula fractures are rare but do accompany SH III and SH IV fractures of the tibia. The displaced fibula fracture typically reduces spontaneously whenever the tibia fracture is reduced, so consider surgical fixation if reduction attempts are unsuccessful.

The most common distal tibia physeal fracture pattern is an SH II. The mechanism for this injury is typically eversion along with plantar flexion, and it is often accompanied by a greenstick fracture of the fibula. The SH II fracture can typically be reduced in the ED using procedural sedation followed by a long-leg splint. Nondisplaced fractures of the distal tibia are rare but can be treated in the ED with immobilization in a stirrup splint along with the added support of a posterior splint. The distal tibia physis in adolescents presents some challenges because it starts closing centrally and progresses medially, but only later does the lateral portion close. This partial closure process in adolescents leads to two distinctive fracture patterns known as the SH III “Tillaux” and the SH IV triplane fracture following a similar mechanism of supination/inversion. The SH III “Tillaux” fracture accounts for about 20% of distal tibia fractures and occurs when the anterior tibiofibular ligament actually pulls off a portion of the lateral tibial physis (Fig. 31-9). The SH IV triplane fracture extends in three planes across the epiphysis, physis, and metaphysis (Fig. 31-10) but only accounts for about 1% of distal tibia fractures. Both the Tillaux and triplane fractures are intra-articular, and surgical fixation should be strongly considered to maintain the articular surface. CT scans often can be helpful in determining the exact amount of displacement and guiding the need for surgical intervention.¹⁵

Clinical decision rules for obtaining radiographs in the ED after ankle injuries have been studied in both adults and children. The popular Ottawa ankle rules (Fig. 31-11) have proven to be very sensitive in detecting clinically significant pediatric ankle fractures and may be applied to school-aged children and adolescents. Exercise caution in patients younger than school age because physeal fractures are much more likely.¹⁶ Radiographs of the ankle should include at least three views utilizing the AP, lateral, and mortise views to get a good view of the talus and its relationship with the tibia and fibula. Intra-articular fractures, displaced fractures, and open fractures need orthopedic consultation in the ED for likely surgical fixation. Precise reduction is extremely important because of the weight-bearing responsibilities and the risk of subsequent osteoarthritis.

Fractures of the foot can result from numerous mechanisms including direct blows, inversions of the ankle, twisting forces, falls, and axial loading. The vast majority of foot fractures involve the forefoot, which consists of the metatarsals and phalanges. Management is typically immobilization and most do well. However, there are some injuries that require surgical fixation and rare injuries such as the Lisfranc or hind foot fractures can have complications if unrecognized.

Metatarsal fractures account for 61% of fractures in the foot, and they may be associated with an impressive amount of soft-tissue swelling. Younger children are more likely to fracture the first metatarsal in falls from a height, whereas children older than 5 years of age are more likely to fracture the fifth metatarsal during sporting activities. Many of these fractures are suspected after examination. Standard radiographs should include an oblique view. The first and fifth metatarsals are frequently solitary fractures, but beware of what appears to be solitary fractures of the second, third, or fourth metatarsal because many of these will have adjoining fractures.¹⁷ The famous “Jones fracture,” occurring in the proximal diaphyseal region of the fifth metatarsal, is uncommon in children. The transverse fractures and avulsions off the fifth metatarsal base (Fig. 31-12) are routine. It is important to recognize the differences between these common fractures and the rare Jones injury because outcomes are much better and surgical intervention is rare. If complications do arise with metatarsal fractures, it is often because of compartment syndrome after severe swelling. The majority of metatarsal fractures can be effectively treated with a short-leg splint, closed reduction if displaced, and an emphasis on supportive care to prevent swelling.

Phalangeal fractures are also common but are straightforward to manage. They can be recognized by point tenderness and radiographic findings. Immobilization is achieved with either a hard-sole shoe or a short-leg splint depending upon the family's preference. SH II fractures may require reduction following a digital block. Indications for surgical fixation are intra-articular fractures of the great toe with displacement at the proximal phalanx, open fractures, or any significant displacement.

Midfoot fractures involving the tarsal bones of the navicular, cuneiforms, and cuboid are rare. These fractures usually result from direct trauma to the midfoot and may be difficult to detect. They are best managed with a nonweight-bearing posterior splint and follow-up unless significantly displaced. The tarsometatarsal fracture/dislocation (Lisfranc) involves the midfoot and is very rare in children (Fig. 31-13). The “Lisfranc joint” is the entire tarsometatarsal junction where the second metatarsal acts as a keystone with very strong ligamentous support. The Lisfranc fracture presents with swelling in the midfoot, marked tenderness, and radiographic suspicion of a fracture at the base of the second metatarsal with tarsometatarsal dislocation. Diagnosing the Lisfranc injury on standard two-view x-ray is difficult, and oblique views are mandatory if suspected. The mechanism is usually a force of strong plantar flexion or abduction of the foot. Recognizing this injury is important because surgical fixation is usually required.

Hindfoot injuries involving the talus and calcaneus are rare in children. Calcaneal fractures in adults are seen with significant falls from height and are often associated with vertebral fractures, contralateral calcaneal fractures, and renal pedicle injuries. These accompanying injuries may occur in children but are much less common. Radiographs of the calcaneus are difficult to interpret and require AP, lateral, and axial views when a fracture is suspected. Some injuries may even require oblique views or a CT scan to make the diagnosis. Subtle compression fractures in adolescents may be detected using Bohler's angle on lateral radiographs, but this measurement is much less reliable in younger children (Fig. 31-14). Any patient with a calcaneal fracture may need AP and lateral views of the thoracolumbar spine to look for an accompanying vertebral fracture. Pain and swelling is often impressive with calcaneal injuries, and ED management consists of nonweight-bearing immobilization with a bulky posterior splint. Nonoperative management of pediatric calcaneal fractures is usually very successful.

Hindfoot fractures of the talus are also rare, and typically involve the talar neck after a mechanism of forced dorsiflexion. Patients present with anterior ankle pain, swelling, and inability to ambulate. Routine radiographs usually reveal the diagnosis, but occasionally a CT scan may be indicated. A talar fracture of recent note is the “snowboarder's fracture.” This fracture of the lateral talar process occurs with dorsiflexion of the ankle and inversion of the hind-foot which is common during snowboarding. Be suspicious of any snowboarder presenting with anterolateral ankle pain. Unless displaced, fractures of the talus can be managed in the ED with nonweight-bearing immobilization in a posterior splint and close orthopedic follow-up. Displacement usually warrants surgical repair, and all talar fractures must be followed closely by an orthopedist because of the risk for osteonecrosis.¹⁸